Emergency critical care AI Flashcards
1
Q
What is the significance of inspiratory dyspnoea?
A
Inspiratory dyspnoea suggests upper airway obstruction.
2
Q
What does expiratory dyspnoea indicate?
A
Expiratory dyspnoea suggests lower airway obstruction, such as feline asthma.
3
Q
What pattern of dyspnoea suggests parenchymal disease?
A
A slow, laboured pattern of dyspnoea suggests parenchymal disease.
4
Q
What pattern of dyspnoea suggests pleural space disease?
A
A rapid, shallow pattern of dyspnoea suggests pleural space disease.
5
Q
How should normal lung sounds be?
A
Normal lungs sounds should be barely audible, but slightly louder cranioventrally.
6
Q
What does the presence of crackles during auscultation suggest?
A
Crackles indicate fluid in the airways, e.g. bronchitis, pneumonia, or pulmonary edema.
7
Q
What do wheezes during auscultation indicate?
A
Wheezes indicate airway narrowing, with expiratory wheezes suggesting intrathoracic airway disease like feline asthma.
8
Q
What does the absence of lung sounds suggest?
A
The absence of lung sounds suggests pleural space disease.
9
Q
What does stertor or stridor suggest during auscultation?
A
Stertor (rostral to larynx) or stridor (larynx or caudal) suggest upper airway obstruction.
10
Q
What does percussion provide valuable information about?
A
when suspicious of pleural space disease.
11
Q
What causes mucous membrane cyanosis?
A
Mucous membrane cyanosis is caused by the presence of deoxygenated haemoglobin in the blood (>11g/dl) and indicates severe hypoxaemia.
12
Q
What is pulse oximetry used for?
A
Pulse oximetry is used to measure the saturation of arterial haemoglobin with oxygen.
13
Q
What is the significance of SaO2 measurement in pulse oximetry?
A
The percentage of haemoglobin saturated with oxygen is determined from SaO2 readings in pulse oximetry.
14
Q
Where can the probe for pulse oximetry be placed?
A
The probe can be placed on the lip, unpigmented digital pads, or unpigmented areas of skin.
15
Q
What is the value of SaO2 at arterial oxygen concentrations as low as 60mmHg?
A
Even at arterial oxygen concentrations of 60mmHg, the SaO2 will be high (>90%) due to the sigmoid shape of the oxygen dissociation curve.
16
Q
What technique can provide extremely helpful information about arterial oxygenation?
A
Arterial blood gas analysis can provide extremely helpful information about arterial oxygenation.
17
Q
Which artery is generally the most accessible for arterial blood gas analysis?
A
The dorsal metatarsal artery is generally the most accessible for arterial blood gas analysis.
18
Q
What is the normal PaO2 when the animal is breathing room air?
A
The normal PaO2 is 80-100mmHg when the animal is breathing room air.
19
Q
How is the alveolar oxygen concentration calculated?
A
The alveolar oxygen concentration (PAO2) is calculated using the equation: PAO2 = FiO2(Patms-PH2O) - 1.2 (PaCO2).
20
Q
What is the simplified equation for calculating PAO2 at sea level with an animal breathing room air?
A
The simplified equation is PAO2 = 150 - 1.2 (PaCO2).
21
Q
What does the alveolar-arterial gradient (PAO2 - PaO2) measure?
A
The alveolar-arterial gradient measures the difference between the alveolar oxygen concentration and the arterial oxygen concentration.
22
Q
What is considered normal for the alveolar-arterial gradient?
A
A normal alveolar-arterial gradient is less than 25mmHg.
23
Q
When is the PaO2:FiO2 ratio more appropriate to use?
A
The PaO2:FiO2 ratio is more appropriate to use when an animal is receiving supplemental oxygen.
24
Q
How should the animal be restrained during the Trans-Tracheal Wash procedure?
A
The animal should be restrained in sternal recumbency or whilst sitting.
25
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26
How should the neck be clipped for the Trans-Tracheal Wash procedure?
The neck should be clipped in the ventral midline (cranial third of the neck).
27
What type of local anesthesia is used during the Trans-Tracheal Wash procedure?
2% lignocaine is used as a local anesthetic.
28
What is the purpose of stabilizing the trachea during the Trans-Tracheal Wash procedure?
The trachea is stabilized to allow for the advancement of a through-the-needle catheter.
29
What should be done after advancing the needle of the catheter into the tracheal lumen during the Trans-Tracheal Wash procedure?
The needle should be removed and sterile saline (0.9%) is instilled in aliquots.
30
What is the purpose of induction of coughing during the Trans-Tracheal Wash procedure?
Induction of coughing helps with the retrieval of fluid.
31
What type of samples are collected during the Trans-Tracheal Wash procedure?
Samples are collected in EDTA for cytology and plain tubes for culture.
32
What should be done after removing the catheter during the Trans-Tracheal Wash procedure?
Digital pressure should be applied over the area for 1-2 minutes.
33
How is the trans-laryngeal approach modified for small dogs during the Trans-Tracheal Wash procedure?
The trans-laryngeal approach is used in small dogs, advancing between the cricoid and thyroid cartilages.
34
When should diagnostic thoracocentesis be performed?
Diagnostic thoracocentesis should be performed in any patient with suspected pleural space disease.
35
What size of needle is adequate for most patients during thoracocentesis?
A 19g butterfly needle with 3-way tap and syringe attached is adequate for most patients.
36
How should the needle be inserted during thoracocentesis if air is suspected?
The needle should be inserted over the dorsal 1/3 of the chest.
37
What is the benefit of using ultrasonography during thoracocentesis?
Ultrasonography is very useful for rapid detection and localization of fluid.
38
What should be done if fluid is obtained during thoracocentesis?
Samples should be submitted for cytology (EDTA and smear), biochemistry (plain tube), and culture (plain tube).
39
How can therapeutic thoracocentesis be performed in large dogs?
In large dogs, an intravenous catheter with additional fenestrations can be used for removal of large volumes of fluid.
40
What can be used as an alternative catheter for therapeutic thoracocentesis in the absence of a pericardiocentesis kit?
A 6Fr dog urinary catheter can be fed through a 3-inch 12g or 14g intravenous catheter.
41
What can help to reduce the 'stinging' associated with injection of lignocaine during thoracocentesis?
Buffering the lignocaine with 1 part 8.4% sodium bicarbonate to 9 parts lignocaine can help to reduce the 'stinging'.
42
What is the purpose of using a centesis valve during thoracocentesis?
A centesis valve allows fluid to be drawn through one way in a syringe.
43
What is the target range for the PaO2:FiO2 ratio?
The target range for the PaO2:FiO2 ratio is 400-500.
44
What is the example range of PaO2 for a dog on nasal oxygen with an FiO2 of 0.40?
The example range of PaO2 for a dog on nasal oxygen with an FiO2 of 0.40 is 160-200mmHg.
45
What are some techniques for administering oxygen therapy?
Some techniques for administering oxygen therapy include flow-by mask, oxygen cage, nasal prongs, and nasal catheter.
46
What can you increase the Fio2 to when using nasal catheters?
One nasal catheter increases FiO2 to about 40%, and 2 can increase it to 80%.
47
When are tracheotomy tubes rarely required?
Tracheotomy tubes are rarely required for bypassing laryngeal obstructions like paralysis, abscesses, and tumors.
48
What is recommended for intubation if laryngeal obstructions cannot be bypassed with a small diameter tube?
In such cases, it is recommended to have a range of intravenous catheters for placing directly into the trachea and attaching to oxygen supplies/anaesthetic circuits.
49
What is the method for placing a tracheotomy tube?
The method for placing a tracheotomy tube involves making a longitudinal skin incision caudal to the larynx, extending it through the sternohyoid muscles, and making an incision between the 3rd and 4th or 4th and 5th tracheal ring.
50
What should be preserved while making the incision for a tracheotomy tube?
While making the incision for a tracheotomy tube, the recurrent laryngeal nerves should be preserved on both sides.
51
How is the tracheotomy tube placed in position?
The tracheotomy tube is placed by pulling up and apart of the nylon loops on either side of the tracheal incision.
52
What is the recommended care for a tracheotomy tube?
The tube needs constant observation to avoid occlusion, needs to be nebulized or have sterile water passed into it every 4 hours, and the tube and wound should be cleaned frequently every 2 hours.
53
How can excessive mucus be suctioned if a tracheotomy tube is in place?
A soft urethral catheter can be used to allow suctioning of the trachea and large airways if excessive mucus is present.
54
How can a nasal catheter be placed?
To place a nasal catheter, local anesthesia is instilled into one or both nostrils, the tube is marked at the level of the medial canthus, and it is inserted into the ventral meatus after lubrication.
55
What is the recommended position for a nasal catheter in dogs?
In dogs, the nasal catheter is aimed at the opposite canine tooth by pushing the nasal planum dorsally and placing the catheter in the ventral meatus.
56
How is the nasal catheter fixed in place?
Once the nasal catheter is in place, it is fixed with butterfly tapes, nylon suture, or tissue glue.
57
What are thoracic drains used for?
Thoracic drains are used to remove large volumes of fluid rapidly or allow for repeated drainage of fluid.
58
What is the advantage of using a 3 way tap with thoracic drains?
Using a 3 way tap with thoracic drains allows for fluid to be emptied in a different direction without adjusting anything.
59
What technique is used to place thoracic drains inserted using a stylet or guidewire?
Thoracic drains inserted using a stylet or guidewire are placed using the Seldinger technique.
60
Where should the drain tip ideally be positioned within the chest?
The drain tip should ideally be positioned at the 2nd intercostal space within the chest.
61
What dressing should be used to secure the tube against the chest?
A flexible net dressing such as Surgifix should be used to secure the tube against the chest.
62
What must all animals with a chest drain in place wear?
All animals with a chest drain in place must wear a Buster collar.
63
What should be done before placing a Stylet Chest Drain?
The animal should be anesthetized if possible before placing a Stylet Chest Drain.
64
What should be done prior to general anesthesia for a Stylet Chest Drain procedure?
Needle thoracocentesis can be performed first either as a diagnostic technique or to improve ventilatory capacity.
65
How should the animal be positioned for chest drain placement?
The animal should be placed in lateral recumbency with the side for chest drain placement uppermost.
66
What area of the chest wall should be prepared for a Stylet Chest Drain procedure?
The prepared area is from just caudal to the shoulder blade to the end of the last rib and from the horizontal vertebral processes dorsally to the sternum in the midline.
67
How can the position of the 8th - 12th ribs be marked for a Stylet Chest Drain procedure?
The position of the 8th - 12th ribs can be marked outside the sterile field.
68
Where should the chest drain be inserted for a Stylet Chest Drain procedure?
The chest drain should be inserted through the skin at around the 10th intercostal space, but enter the thorax around the 8th intercostal space.
69
Why is the chest drain placed ventrally and dorsally?
The chest drain is placed ventrally to collect fluid and dorsally to collect air.
70
How should the chest drain be measured for placement?
The chest drain should be measured so that the cranial end will lie level with the 2nd or 3rd rib and all holes are within the chest.
71
What should be done while inserting the chest drain into the thoracic cavity?
The chest drain should be tapped into the thoracic cavity using the heel of the dominant hand and supported firmly 1-2 cm above the chest wall.
72
What are the learning objectives of this module?
Understand how to perform a major body system assessment, recall the importance of perfusion and ventilation in emergency medicine, consider options for vascular access in critical patients, reflect on options for analgesia in emergencies, identify different respiratory patterns, understand the clinical findings and causes of dyspnea, consider options for oxygenation, understand the basics of thoracic point of care ultrasound, understand the effect pleural air or effusion has on ventilation, recall potential ways to drain pleural effusions, understand how to place both Stylet and Seldinger chest drains, and reflect on hands-off management of dyspneic cats.
73
Why is staying calm essential in emergency situations?
Staying calm is essential as it allows for a logical approach to triaging and stabilizing emergency patients effectively.
74
What are the key principles in emergency medicine for an emergency patient?
Ventilation (getting oxygen into the patient and removing carbon dioxide) and perfusion (moving oxygen to the tissues and removing carbon dioxide).
75
What does anaerobic metabolism result in?
Anaerobic metabolism is less efficient and produces metabolites such as lactate, which leads to metabolic acidosis.
76
What is the meaning of the term 'triage'?
Triage comes from the French word meaning 'to sort.'
77
What are the two ways in which 'triage' is applicable in veterinary emergencies?
Triage allows clinicians to prioritize which animal requires the most urgent attention and which of an individual animal's problems needs the most urgent treatment.
78
What should the initial triage assessment include?
A capsule history (age, sex, nature and duration of presenting problem, any ongoing medical problems) and a limited physical examination.
79
What are the key components to assess during the initial triage assessment?
Airway, breathing, circulation, mucous membrane color/CRT, brief urinary and neurological assessment.
80
What is the purpose of obtaining vascular access in emergency presentations?
Vascular access allows for fluid and drug therapy.
81
When should vascular access be obtained in emergency presentations?
Vascular access should be obtained early and if possible as part of the triage procedure.
82
What should be considered when placing peripheral catheters?
The position of the catheter is important, for example, with fascial or forelimb trauma, saphenous catheters may be helpful.
83
How is the needle held during insertion in a 'pistol grip'?
With the handle in the palm of the hand.
84
What motion is used while inserting the needle into the bone?
A slight twisting motion.
85
What should the needle feel like once it is in position?
Firmly seated.
86
What is recommended maximum flow rate for the needle?
11ml/min
87
How often should a new needle be placed at a different site?
After 72 hours.
88
What are some complications of needle insertion?
Infection, damage to growth plates, fat embolization.
89
What type of opioids are initially used for emergency analgesia?
Potent short acting opioids, like pethidine.
90
How long does 5mg/kg i/m pethidine provide good analgesia?
Approximately 2 hours.
91
Which full agonist opioid can be continued after pethidine?
Methadone or morphine.
92
Is methadone or morphine preferred for inducing less vomiting?
Methadone.
93
How long should methadone not be used for?
Longer than 24 hours.
94
In which animals can buprenorphine provide good analgesia?
Cats.
95
What is the recommended dose of buprenorphine for cats?
0.01-0.02mg/kg q6-8hours.
96
Which route can buprenorphine be given in difficult animals?
Sublingually.
97
What can be helpful after chest drain placement to improve patient comfort?
Combinations of lidocaine and bupivacaine.
98
What is the term for combining different analgesic agents to improve pain relief?
Multimodal analgesia.
99
What is the drug loading dose for morphine?
0.5mg/kg i/m.
100
What is the CRI dosage range for lidocaine?
0.5-1mg/kg/hour.
101
What is the CRI dosage range for ketamine?
0.1-0.25mg/kg/hour.
102
What should be assessed, stabilized, and monitored in respiratory emergencies?
The respiratory system.
103
Why is relief of respiratory distress a true emergency?
Because it can be life-threatening.
104
What body position do dyspnoeic animals often adopt to maximize tidal volume?
Neck extended and elbows abducted.
105
What is the correct position for the chest drain tip?
At 2nd or 3rd rib
106
How can correct positioning of the chest drain be verified?
Radiographically
107
What should be done to prevent air entry and allow connection to rubber tubing?
Place a gate clamp
108
What is the purpose of a Heimlich valve?
Allow drainage of air
109
What is the consequence if the Heimlich valve chamber becomes flooded with fluid?
It no longer works
110
How is the chest drain secured?
Using a box suture and a Chinese finger trap suture
111
How is the chest drain removed?
By placing firm pressure over the subcutaneous tunnel and pulling it out briskly
112
What should be done after the chest drain is removed?
Maintain pressure for 2-3 minutes and allow the skin incision to heal by secondary intention
113
What can be done to improve comfort levels if there is pleural irritation caused by a drain?
Instillation of dilute long acting local anaesthetic
114
How much pleural fluid is typically produced as a result of a chest drain?
0.5-1 ml/kg/day
115
Where is the skin incision made for placement of a guidewire chest drain?
At the junction of the middle and dorsal two thirds of the thorax over the 8th intercostal space
116
What is the purpose of holding the guide wire in place during a guidewire chest drain procedure?
To prevent accidentally losing it completely into the pleural space
117
How is the catheter introduced during a guidewire chest drain procedure?
Along the cranial border of the rib to avoid the intercostal vessels and nerves
118
How is the catheter secured to the skin in a guidewire chest drain procedure?
Using suture material passed through the holes in the wings
119
What is the key step in classifying effusions?
Determining the type of effusion present
120
Why are saphenous catheters not recommended in animals with a GDV?
Venous return may be impeded in animals with a GDV.
121
In extremely hypovolemic animals, how many peripheral catheters may be needed?
2 or more peripheral catheters may be needed in extremely hypovolemic animals.
122
What is the advantage of using central jugular lines with multiple lumens?
Different ports can be used for different functions.
123
When are central lines used?
Central lines are used when perfusion is very poor.
124
What can be administered through a central line?
Hyperosmolar solutions such as parenteral nutrition and glucose solutions >5%.
125
What can blood collected from the hub of a catheter be used for?
Obtaining an emergency database including PCV/TS, blood glucose, and electrolyte analysis.
126
Why is anaesthesia not usually needed for placement of a Central Line?
Placement usually only requires sedation or brief anaesthesia.
127
What is the Seldinger technique?
A technique where a wire is passed through a small gauge catheter before exchanging it for a larger bore central catheter over the wire.
128
What should be done to make the jugular vein more prominent during placement of a central line?
A small fluid bag can be placed under the neck.
129
What are the preferred sites for placement of intraosseous catheters in pediatric patients?
Trochanteric fossa of femur, medial aspect of proximal tibia, or greater tubercle of humerus.
130
What can be substituted for commercially available intraosseous catheters in young animals?
A suitably sized injection needle can be used.
131
What is the first step in placing an intraosseous infusion needle?
Inject a small amount of 2% lignocaine at the insertion site.
132
What samples are collected for cytology, biochemistry, and culture?
Cytology, biochemistry, and culture samples are collected.
133
How can protein content in fluid be measured?
Protein content in fluid can be measured using a refractometer.
134
What does a high protein content in effusion suggest?
A high protein content in effusion suggests an exudate.
135
What does a low protein content in effusion suggest?
A low protein content in effusion suggests a transudate.
136
What are the characteristics of a transudate fluid?
Transudate fluid has a specific gravity <1.017, protein <25 g/L, and <1000 nucleated cells/mm3.
137
What are the characteristics of a modified transudate fluid?
Modified transudate fluid has a specific gravity of 1.017-1.025, protein content of 25-60 g/L, and 7000 nucleated cells/mm3.
138
What are the characteristics of an exudate fluid?
Exudate fluid has a specific gravity >1.025, protein >25 g/L, and >7000 nucleated cells/mm3.
139
What is the importance of oxygen in the medical management of respiratory distress?
Oxygen is the most important drug in most patients with respiratory distress.
140
What medication should be administered if congestive heart failure is suspected?
Frusemide (2mg/kg) should be administered if congestive heart failure is suspected.
141
What medication is effective for cats with dyspnoea secondary to feline asthma?
Intramuscular terbutaline or inhaled salbutamol can be effective for cats with dyspnoea secondary to feline asthma.
142
What is the shock dose for dogs?
The shock dose in dogs is 90ml/kg.
143
What is the shock dose for cats?
The shock dose in cats is 40-60ml/kg.
144
What is the bolus dose given to dogs prior to assessing response?
Boluses of 30ml/kg are given to dogs.
145
What is the bolus dose given to cats prior to assessing response?
Boluses of 15ml/kg are given to cats.
146
When are colloids considered appropriate in fluid resuscitation?
Colloids are appropriate in cases with severe hypovolaemia/hypoproteinaemia.
147
What is the total dose of colloid given for severe hypovolaemia/hypoproteinaemia?
Boluses of approx. 5ml/kg are given, repeated as required, up to 20ml/kg total dose.
148
How should the dose of crystalloid be reduced when colloids are administered?
The dose of crystalloid should be reduced by 50%.
149
What is the purpose of hypertonic saline in fluid resuscitation?
Hypertonic saline can be considered in simple hypovolaemic shock if dehydration is not present.
150
What is the dose of hypertonic saline used in fluid resuscitation?
A dose of 4-5ml/kg is used, followed by appropriate isotonic fluid therapy.
151
What situations require additional care in fluid resuscitation?
Ongoing bleeding, head trauma, concurrent heart disease.
152
How can abdominal bleeding be helped in fluid resuscitation?
Placement of an abdominal bandage to maintain pressure within the abdomen.
153
Why should a more cautious approach be taken in fluid resuscitation for patients with pulmonary contusions?
Aggressive fluid therapy can lead to increased pulmonary haemorrhage and/or fluid into the lungs.
154
What is the recommended initial bolus dose for fluid resuscitation in patients with pulmonary contusions?
Boluses of 3-5ml/kg of crystalloid should be used initially.
155
How should fluid resuscitation be managed in patients with head trauma?
A balancing act between maintaining arterial blood pressure and minimizing increases in intracranial pressure.
156
What combination of fluids may benefit head trauma patients in fluid resuscitation?
Hypertonic saline (3-5ml/kg of 7.5% NaCl) and colloid (2-3ml/kg of 6% Hetastarch).
157
What measures can be taken to reduce intracranial pressure in head trauma patients?
Elevation of the head, avoidance of jugular compression, use of mannitol, and ventilation.
158
What should be done when a dehydrated patient shows signs of hypovolaemia?
Initial shock boluses of crystalloid +/- colloid can be given until the patient is stable.
159
How should isotonic crystalloids be administered to replace fluid deficits in a dehydrated patient?
At a rate designed to replace the deficit and provide for maintenance requirements over 12-24 hours.
160
What is the replacement volume for a 10kg dog with signs of hypovolaemia and dehydration?
700ml (estimated dehydration of 7% = 350ml, replace over 6 hrs, then 350ml over next 18hrs).
161
What fluids are given to normalize heart rate and improve pulse quality in a dehydrated dog?
A 20ml/kg bolus of Hartmann's solution is given over 10 minutes.
162
What is septic shock characterized by?
Septic shock often has components of absolute hypovolaemia, relative hypovolaemia, distributive shock, and sometimes cardiogenic shock.
163
What is central to the management of septic shock?
Fluid therapy, often requiring aggressive use of crystalloids and colloids.
164
What are some organs that can be affected by oedema?
Lungs and peripheral organs can be affected by oedema.
165
Which type of colloids can be useful for oedema?
Hetastarch can be useful for oedema.
166
How can plasma be beneficial for septic patients?
Plasma can provide colloidal support, clotting factors, and proteases for septic patients.
167
What should be carefully monitored to guide therapy for septic patients?
Physical parameters, urine output, arterial blood pressure, and CVP should be monitored.
168
What treatment can be considered if systolic arterial blood pressure remains <90mmHg despite aggressive fluid therapy?
Treatment with vasotropes and/or inotropes may need to be considered.
169
What is the recommended dose of dopamine for its vasopressor effects?
Dopamine can be used at doses of 3-10ug/kg/min for its vasopressor effects.
170
When is dobutamine typically used?
Dobutamine is typically used when a positive inotrope is required or systolic function is dramatically reduced in septic shock.
171
What should be monitored when administering dopamine or dobutamine?
Side-effects such as tachydysrhythmias should be closely monitored.
172
What type of antibiotics are indicated in patients with septic shock?
Intravenous antibiotics are indicated in patients with septic shock.
173
Why should broad-spectrum antibiotics be given until culture results are available?
Broad-spectrum antibiotics help protect against the effects of translocation of bacteria from the GI tract.
174
What are some recommended combinations of antibiotics for septic patients?
Cephalosporin or amoxicillin-clavulanic acid with a fluoroquinolone is recommended.
175
What can provide supplemental oxygen to maximize oxygen delivery in septic patients?
Supplemental oxygen can provide increased oxygen delivery to the tissues in septic patients.
176
What is DIC and how can it be treated in septic patients?
DIC is disseminated intravascular coagulopathy and it may require treatment with plasma +/- heparin.
177
What should be paid attention to in septic patients besides therapy?
Appropriate analgesia and nutrition should be considered in septic patients.
178
How can adequate nutrition reduce the risk of intestinal translocation of bacteria in septic patients?
Adequate enteral nutrition via feeding tubes can reduce the risk of intestinal translocation of bacteria.
179
What are the different types of crystalloid solutions?
Hypotonic, hypertonic, and isotonic solutions are the different types of crystalloid solutions.
180
Why should great care be taken when administering hypotonic fluids?
Hypotonic fluids can cause marked drops in serum tonicity and severe changes in electrolytes.
181
Which fluids are commonly used as replacement fluids and maintenance fluids in veterinary practice?
Hartmann’s solution and 0.9% NaCl are commonly used as replacement and maintenance fluids.
182
How much of the infused volume remains in the vasculature after 30 minutes with crystalloid solutions?
Only 25% of the infused volume remains in the vasculature after 30 minutes with crystalloid solutions.
183
What is pulsus paradoxus?
Pulsus paradoxus describes the apparent absence of a peripheral pulse during inspiration despite the presence of a heartbeat.
184
How is pulsus paradoxus defined?
Pulsus paradoxus is defined as a drop in systolic arterial blood pressure (SABP) of ≥10mmHg during inspiration.
185
Why does pulsus paradoxus occur?
During inspiration, the intra-thoracic pressure falls, leading to increased blood flow preferentially into the pulmonary vasculature and the right side of the heart.
186
What happens to right ventricular filling during inspiration?
During inspiration, the right ventricular filling is accentuated, increasing right ventricular volume at the expense of the left ventricle.
187
How can pericardial effusion be confirmed?
Pericardial effusion can be confirmed through further investigation, such as thoracic radiographs or echocardiography.
188
What are the clinical examination findings associated with pericardial effusion?
Pericardial effusion may present with a very large cardiac silhouette, increased sternal contact, elevated trachea, and a globular heart on thoracic radiographs.
189
What are the ECG findings in pericardial effusion?
ECG usually reveals a normal sinus rhythm or a compensatory sinus tachycardia, with low voltage QRS complexes (<1mV in all leads) occurring in approximately 50% of cases.
190
What is electrical alternans in pericardial effusion?
Electrical alternans is the beat-to-beat variation in the size of the QRS and ST segments seen in two-thirds of pericardial effusion cases, caused by the movement of the heart within the fluid-filled pericardium.
191
What is the most sensitive and specific way to diagnose pericardial effusion?
Echocardiography is the most sensitive and specific way to diagnose pericardial effusion, allowing for the assessment of the atrial free wall and exclusion of heart base masses.
192
What is the purpose of pericardiocentesis?
Pericardiocentesis is both a diagnostic and therapeutic technique used to relieve pericardial tamponade and improve cardiac output.
193
What is the equipment used for pericardiocentesis?
Pericardiocentesis can be performed using a commercial Seldinger pericardiocentesis kit with a stiff pericardial catheter or a wide bore catheter.
194
What can the analysis of pericardial fluid retrieved during pericardiocentesis help with?
The analysis of pericardial fluid can help exclude sepsis and look for evidence of neoplasia in pericardial effusions.
195
What are some good choices for reducing steroid dose and side effects?
Azathioprine and Cyclosporine.
196
How long does it take for Azathioprine and Cyclosporine to have full immunosuppressive action?
Between 7-10 days.
197
What should be considered to reduce the risk of steroid-associated GI hemorrhage?
Gastro-protection.
198
What are some options for gastro-protection?
Sucralfate, cimetidine, ranitidine.
199
What is the recommended dose of Sucralfate for gastro-protection?
0.5-1g/QID p.o.
200
What is the recommended dose of Cimetidine for gastro-protection?
5-10mg/kg/TID SLOW i/v.
201
What is the recommended dose of Ranitidine for gastro-protection?
2mg/kg/BID SLOW i/v.
202
Why should dogs with IMHA be treated with anticoagulant therapy?
To reduce the risk of thromboembolic disease.
203
What are some options for anticoagulant therapy?
Very low dose aspirin or low molecular weight heparin.
204
What is the recommended dose of aspirin for anticoagulant therapy?
0.5mg/kg BID.
205
What is the recommended dose of Fragmin for anticoagulant therapy?
100IU/Kg BID.
206
What is the purpose of an i/v human IgG infusion in IMHA?
To reduce red cell destruction.
207
What is a possible premedication for the administration of i/v human IgG?
Chlorphenamine (4-8mg i/m).
208
What do polyclonal human antibodies do in IMHA treatment?
Block macrophage Fc receptors, reducing platelet destruction and antibody production.
209
Why should veterinarians look for underlying triggers in IMHA?
To find and address the cause of the condition.
210
What techniques can be used for diagnosing abdominal fluid in animals?
Abdominocentesis and Peritoneal Lavage.
211
How can ultrasound be used during abdominocentesis?
To guide the operator to small pockets of fluid.
212
What should be considered to exclude septic peritonitis?
Timely collection and classification of abdominal fluid.
213
What type of fluid should be collected for cytology analysis during abdominocentesis?
EDTA.
214
What type of fluid should be collected for biochemistry and culture analysis during abdominocentesis?
Plain fluid.
215
What should be avoided during abdominocentesis to prevent injury to other organs?
Penetration of the bladder, spleen, or other viscera.
216
When is peritoneal lavage performed?
To investigate suspected abdominal inflammation with small volumes of fluid.
217
How is local anesthesia administered during peritoneal lavage?
By infiltrating it around the umbilicus.
218
What type of catheter is typically used for peritoneal lavage?
A 14g catheter.
219
What care should be taken during peritoneal lavage to prevent infection?
Performing the procedure in as aseptic a manner as possible.
220
How do gelatins and hydroxyethyl starches affect COP?
Gelatins have a rapid effect but are excreted quickly, while hydroxyethyl starches remain in circulation for longer.
221
How are large molecules like hydroxyethyl starches removed from circulation?
They are either cleared by the monocyte phagocytic system or broken down by plasma enzymes.
222
What is the action of polydisperse fluid colloids on COP?
Their action on COP exponentially declines, with small molecules being cleared more quickly and larger ones more slowly.
223
What coagulation abnormalities are associated with colloids?
Coagulation abnormalities have been documented in both humans and experimental studies in dogs.
224
What is the suggested limit for colloid usage in veterinary patients?
Most authors suggest limiting colloid usage to 20ml/kg/day.
225
What is the potential risk of using colloid types in veterinary patients?
All forms of colloids have been associated with rare anaphylactic reactions in veterinary patients.
226
How is human albumin used to improve colloid osmotic pressure in humans?
Human albumin, purified from plasma, carries hormones, drugs, and other substances to increase COP.
227
What is the limitation in using fresh frozen plasma for albumin transfusion in dogs?
Fresh frozen plasma only contains a limited amount of albumin, making it inefficient for providing COP.
228
What is the availability of higher-concentration purified human albumin?
Purified human albumin is available in higher concentrations of 20-25%.
229
Why must caution be exercised when using human albumin in canines?
Human albumin is only 79% homologous to canine albumin, increasing the risk of hypersensitivity reactions.
230
What are the new developments in canine blood transfusions in 2007?
The establishment of a national blood registry and a charity collecting blood products for dogs.
231
What are the most important blood groups in dogs?
The most important blood groups in dogs are DEA 1 and 1.7.
232
Can dogs naturally develop antibodies to the important dog blood groups?
Dogs do not have naturally occurring antibodies to these antigens.
233
What is the usefulness of typing cards for identifying DEA 1.1 positive dogs?
Typing cards can identify DEA 1.1 positive dogs, but they have a significant false positive rate.
234
Do most dogs require blood typing or cross-matching for a first transfusion?
Most dogs can safely receive a first transfusion without blood typing or cross-matching.
235
What is the normal heart rate in dogs?
80-120bpm
236
What is the normal heart rate in cats?
160-180bpm
237
What can cause tachycardia?
Hypovolaemia, pain, or stress
238
How should tachycardia in patients with simple hypovolaemia respond?
Rapidly to appropriate boluses of intravenous fluids
239
What should persistent tachycardia prompt a search for?
Ongoing fluid loss/haemorrhage or causes of pain
240
What can be gained from careful and thoughtful palpation of pulses?
Much information
241
How should a normal pulse feel?
Strong and 'full' as it passes under the clinician's fingers
242
What can a bounding pulse indicate?
Hyperdynamic states (e.g. early septic shock)
243
How does the pulse feel in decompensated shock?
Weak and peripheral pulses may not be palpable
244
What can variations in pulse quality be caused by?
Cardiac dysrhythmias or raised right atrial pressures
245
What can pale mucous membranes indicate?
Anaemia or vasoconstriction
246
What does venous distension of the jugular vein indicate?
Right-sided heart disease or volume overload
247
How can raised right atrial pressure be determined?
Performing the hepatojugular reflux test
248
What can cats with septic shock often present with?
Hypothermia, severe hypotension, bradycardia, and jaundice
249
What can lactate measurement determine?
Severity of tissue hypoperfusion and monitoring response to therapy
250
What is a normal lactate level in dogs?
<2.5mmol/l
251
What does a high anion-gap metabolic acidosis indicate in hypovolaemic patients?
Increased production of lactate
252
What can measurement of urine output indicate?
Renal perfusion and cardiac output
253
What is the minimum urine output that generally indicates adequate renal perfusion?
1ml/kg/hour
254
When should possibilities of ongoing hypovolaemia, obstruction/removal of the catheter, or renal shutdown be considered?
If urine output reduces
255
What can arterial blood pressure measurement provide information about?
Cardiac function and tissue perfusion
256
What are the learning objectives of this module?
The learning objectives include discussing the consequences of poor perfusion and recalling the causes of poor perfusion and types of shock.
257
Who is the module developer for this course?
The module developer is Simon Tappin, MA VetMB GPCert(SAP) CertSAM DipECVIM-CA MRCVS.
258
What is the main aim in assessment and stabilisation of the cardiovascular system?
The main aim is to restore and maintain tissue perfusion.
259
What causes tissue perfusion to be reduced?
Tissue perfusion can be reduced due to hypovolaemia, reduced cardiac function, or redistribution of fluid.
260
What is the definition of dehydration?
Dehydration is usually assumed to mean water and solute losses which exceed intake.
261
What are the classic clinical signs of hypovolaemia?
The classic clinical signs include tachycardia, altered pulse, tacky mucous membranes, and reduced skin turgor.
262
What is the basic physiology of total body water?
Total body water is subdivided into intracellular fluid and extracellular fluid, which includes interstitial fluid and plasma.
263
What are the compensatory mechanisms to hypovolaemia?
Decreased cardiac output results in stimulation of the renin-angiotensin-aldosterone system and the sympathetic nervous system.
264
What happens when compensation fails in severe hypovolaemia?
Tissue perfusion and oxygenation are reduced, leading to a shift to anaerobic metabolism and increased lactate production.
265
What are the physical parameters that should be assessed in the cardiovascular system?
The physical parameters that should be assessed include heart rate and rhythm, pulse rate and quality, and mucous membrane.
266
What is the 'gold standard' for measuring blood pressure?
Direct blood pressure measurement is the 'gold standard.'
267
What is required for direct blood pressure measurement?
Placement of an arterial catheter, usually into the dorsal pedal artery, is required.
268
What technique is becoming more widely available for blood pressure measurement?
Indirect measurement of blood pressure is becoming more widely available.
269
What does indirect blood pressure measurement rely on?
Indirect techniques rely on the use of a cuff to occlude arterial flow.
270
What is the recommended width of the cuff for blood pressure measurement?
The width of the cuff should be 40% of the circumference of the patient's limb.
271
Where should the cuff be placed for blood pressure measurement?
The cuff should be placed in a position on the limb/tail which is level with the heart.
272
What are the two types of techniques for blood pressure measurement?
Oscillometric techniques and Doppler techniques are used for blood pressure measurement.
273
How should blood pressure readings be taken with oscillometric and Doppler techniques?
With both techniques, the average should be taken of several readings to reduce error.
274
What is central venous pressure (CVP) monitoring used for?
CVP is useful to assess cardiac output and blood volume relative to vascular capacity.
275
How is CVP measured?
CVP can be measured electronically via a transducer or using a water manometer.
276
What is the normal range for CVP?
Normal CVP is 0-5cm water.
277
What is the aim of treatment for hypovolaemic shock?
The aim of treatment is to restore tissue perfusion and oxygenation.
278
What is the initial treatment of choice for hypovolaemic shock?
Isotonic crystalloids are generally the initial treatment of choice.
279
What is the recommended approach to fluid therapy for hypovolaemic shock?
A bolus approach to fluid therapy is recommended.
280
What should be considered in patients with persistent tachycardia and poor pulse quality?
The possibility of underlying heart disease should be considered.
281
What should lack of response to appropriate therapy prompt in hypovolaemic shock?
A search for undetected fluid losses should be prompted.
282
What is the purpose of instilling sterile saline into the abdomen during a procedure?
To facilitate analysis of fluid and identify possible underlying causes.
283
How can the presence of septic peritonitis be determined?
By comparing glucose concentrations in abdominal fluid to those in the blood.
284
What is the significance of a glucose difference >1.15mmol/l between blood and effusion?
It is 100% sensitive and specific in diagnosing septic peritonitis in dogs and cats.
285
What are the categories of possible underlying aetiologies of abdominal effusions?
Similar categories as for thoracic effusions.
286
What are the main differences between a transudate and a modified exudate?
Gross appearance, specific gravity, protein content, and nucleated cell count.
287
What are the main cytological findings in septic effusions?
Degenerate neutrophils, macrophages, and intracellular bacteria.
288
What is a common clinical sign of pericardial effusion?
Jugular distension.
289
What is the function of the pericardium?
To prevent the myocardium from over expanding and protect the heart from adhesions.
290
What are the common signs of right-sided heart failure?
Ascites, lethargy, and coughing.
291
What should be given as a first transfusion in the future?
DEA1 negative or type-matched blood
292
What are the characteristics of an ideal blood donor for dogs?
<8 years old, >25kg, friendly, healthy, vaccinated, never been pregnant or received a transfusion, and DEA 1 negative
293
What diseases should be considered in dogs that have traveled to countries where they are endemic?
Dirofilaria, Leishmania, Babesia, Erhlichia
294
Where is blood collected from in dogs?
The jugular vein
295
What are the blood groups in cats?
A, B, and AB
296
What are the characteristics of an ideal blood donor for cats?
<8 years old, >5kg, friendly, healthy, vaccinated, never been pregnant or received a transfusion, and FeLV/FIV/Mycoplasma negative
297
What sedation is used for cats prior to blood collection?
Midazolam/ketamine
298
What is the basic cross-matching procedure for blood typing in cats?
Collect blood samples, separate plasma, mix RBCs from donor with plasma from donor and recipient, observe for agglutination
299
How long can whole blood be stored in the fridge?
3-5 weeks
300
What are the components of fresh whole blood?
Packed red blood cells and plasma
301
What is cryoprecipitate rich in?
Factor VIII and von Willebrand's
302
What is the purpose of bicarbonate in Hartmann's solution?
Buffering acidotic patients and returning plasma pH to normal.
303
Why are potassium containing fluids traditionally contraindicated in acidotic patients?
Due to their high potassium content.
304
How does 0.9% NaCl differ from Hartmann's solution in terms of acidification?
0.9% NaCl is an acidifying fluid due to its high chloride content.
305
When would lactate-containing fluids be useful in animals?
In very young hypoglycaemic animals as an easily utilised energy source.
306
Why are lactate-containing fluids avoided in animals with liver disease and diabetic ketoacidosis?
Due to their decreased ability to convert lactate to bicarbonate.
307
How can potassium supplementation be given to patients receiving Hartmann's solution?
With the addition of potassium chloride to 0.9% sodium chloride.
308
What are the benefits of administering hypertonic saline?
Rapid expansion of circulating vascular volume, reduced endothelial cell swelling, immunomodulation, decreased blood viscosity, and improved cardiac contractility.
309
What are the two types of artificial colloids available in the United Kingdom?
Gelatins and hydroxyethyl starches.
310
What is the average molecular weight of gelatins?
Around 30-35kD.
311
What is the initial action of vascular expansion after colloid administration due to?
Number of moles infused rather than their size or charge.
312
How can platelet-rich plasma be prepared?
Platelet-rich plasma can be prepared by a centrifuge process.
313
What is the rule of thumb for transfusing blood to raise recipient PCV by 1%?
Volume of donor blood required = recipient wt (kg) x [85*x (desired PCV-current PCV)] PCV of donor blood.
314
What is the initial rate of administration for blood transfusion?
The initial rate of administration should be 0.25ml/kg/hour for the first 15-30 minutes.
315
What are the signs of a transfusion reaction?
The signs of a transfusion reaction include tremors, vocalization, tachypnoea, tachycardia, vomiting, and urticaria.
316
What is the aim in completing a blood transfusion?
The aim is to complete the transfusion within 4 hours to reduce risk of bacterial proliferation.
317
What are the possible causes of transfusion reactions?
The possible causes of transfusion reactions include RBC incompatibility, reactions to plasma proteins, reactions to white blood cells, and reactions to platelets.
318
What is the management of Immune Mediated Haemolytic Anaemia (IMHA)?
Management of IMHA includes large bore i/v catheter placement, diagnostic tests, increasing oxygen content, volume resuscitation, steroid administration, and considering second-line immunosuppressive drugs.
319
What is the purpose of sedation during urinary catheter placement?
To help with the procedure
320
Which opioids are commonly used for sedation during urinary catheter placement?
0.1mg/kg butorphanol i/v
321
How is the animal positioned during urinary catheter placement?
In sternal recumbency
322
What area of the chest is clipped and prepared aseptically for urinary catheter placement?
From the 3rd to the 7th rib, from approximately ½ way down the chest wall to the sternum
323
What is the purpose of monitoring the ECG during urinary catheter placement?
To monitor any epicardial irritation during the procedure
324
What should be done to avoid lung tissue during urinary catheter placement?
Pass the catheter between the right cranial and middle lung lobes through the cardiac notch
325
What is the purpose of using a Seldinger kit during urinary catheter placement?
To allow the wire to be fed through into the pericardium
326
What is usually obtained when the catheter is in the pericardial space during urinary catheter placement?
Fluid that is usually blood tinged
327
What samples are collected for analysis during urinary catheter placement?
EDTA for cytology, plain for biochemistry & culture
328
What should be attached to allow complete drainage during urinary catheter placement?
A three-way tap & extension set
329
How should platelet numbers be evaluated?
Platelet numbers should be evaluated under oil immersion (x100) to evaluate the platelet numbers specifically.
330
Where should platelets be counted during evaluation?
Platelets should be counted in the area just behind the feathered edge, where the red cells are just touching one another.
331
What is the equivalent platelet count for each platelet counted manually per high power field?
Each platelet counted manually per high power field is equivalent to roughly 15x109/l platelets.
332
What should be examined in the smear for platelet clumps?
The edges of the smear should be examined for platelet clumps.
333
What should be examined in the blood tube for potential clots?
The blood tube should be examined for potential clots.
334
What is the significance of macrothrombocytes?
Macrothrombocytes may indicate regenerative thrombopoiesis.
335
What is the primary coagulation proportional to?
Primary coagulation is more proportional to the volume of platelets, rather than the actual number of platelets present.
336
How should bleeding be prevented in the management of immune-mediated thrombocytopenia?
To prevent further bleeding, no jugular sampling should be done and bleeding can be controlled with pressure bandages as needed.
337
What should be done to control local bleeding in the management of immune-mediated thrombocytopenia?
Local bleeding should be controlled through methods such as pressure, surgery, packs, or phenylephrine.
338
What should be done regarding intravenous access in the management of immune-mediated thrombocytopenia?
A large bore i/v catheter should be placed.
339
What should be collected from the catheter, if possible?
A minimal database should be collected from the catheter if possible.
340
What should be done for volume resuscitation in the management of immune-mediated thrombocytopenia?
Volume resuscitation should be done as appropriate.
341
How can platelet numbers be increased in the management of immune-mediated thrombocytopenia?
Whole blood can be considered to increase platelet numbers. 10ml/kg of whole blood will raise the platelet count by approximately 10x109/l.
342
What should be done to replace blood loss in the management of immune-mediated thrombocytopenia?
Transfusions of packed red cells/Oxyglobin should be given as needed to replace blood loss.
343
What medication should be given to reduce platelet destruction in the management of immune-mediated thrombocytopenia?
Steroids, such as dexamethasone i/v 0.5mg/kg SID then switched to prednisolone (1mg/kg/BID p/o) as appropriate, should be given.
344
How should steroids be tapered in the management of immune-mediated thrombocytopenia?
Steroids are normally tapered once platelet numbers have returned to normal, reduced over approximately 4-6 months (25% reduction each month, moving to EOD treatment at about ½ way through treatment).
345
What should be considered if tick-borne disease is possible in the management of immune-mediated thrombocytopenia?
Antibiotics should be considered if tick-borne disease (e.g., Anaplasma) is possible, and blood should be submitted for PCR or covered with doxycycline (10mg/kg/SID p/o).
346
What are good choices for second-line immunosuppressive drugs in the management of immune-mediated thrombocytopenia?
Azathioprine (2mg/kg/SID moving to every other day treatment after 10-14 days) and cyclosporine (5mg/kg/SID) are good choices for second-line immunosuppressive drugs.
347
What is the reported time for full immunosuppressive action for azathioprine and cyclosporine?
Both azathioprine and cyclosporine are reported to take between 7-10 days for full immunosuppressive action.
348
What is the possible effect of vincristine on platelet numbers in the management of immune-mediated thrombocytopenia?
Vincristine leads to the shattering of megakaryocytes and increased platelet numbers.
349
What might be the effect of vincristine on platelet functionality in the management of immune-mediated thrombocytopenia?
It is not known if the platelets increased by vincristine are functional, but it is postulated that vincristine may accumulate in macrophages, inhibiting their action.
350
What effect did vincristine have on hospitalization stays of ITP patients, according to a recent paper?
Vincristine at admission reduced hospitalization stays of ITP patients by 24 hours, according to a recent paper.
351
What precautions should be taken regarding the patient after vincristine administration?
The patient should now be considered cytotoxic after vincristine administration.
352
Why should gastro-protection be considered in the management of immune-mediated thrombocytopenia?
Gastro-protection reduces blood loss as a result of ITP and also reduces the risk of steroid-associated GI hemorrhage.
353
What medications can be used for gastro-protection in the management of immune-mediated thrombocytopenia?
Sucralfate (0.5-1g/QID p/o) and cimetidine (5-10mg/kg/TID SLOW i/v) or ranitidine (2mg/kg/BID SLOW i/v) can be used for gastro-protection.
354
What is the purpose of an i/v human IgG infusion in the management of immune-mediated thrombocytopenia?
An i/v human IgG infusion (0,5mg/kg over 4 hours) is given to reduce platelet destruction.
355
What precautions should be taken before an i/v human IgG infusion?
Premedication with chlorphenamine (4-8mg i/m as a one off) is suggested before an i/v human IgG infusion to prevent possible transfusion reactions due to the small percentage of human albumin contained in the product.
356
What is the effect of polyclonal human antibodies in the management of immune-mediated thrombocytopenia?
Polyclonal human antibodies block macrophage Fc receptors reducing platelet destruction. They also dilute out anti-platelet antibodies and have long term feedback reducing antibody production.
357
What should be considered for chronic ongoing cases in the management of immune-mediated thrombocytopenia?
Splenectomy should be considered for chronic ongoing cases.
358
What is the purpose of glucometers in blood glucose monitoring?
Glucometers are used for cheap and easy blood glucose monitoring.
359
Why do hand held glucometers often underestimate blood glucose at low values?
Hand held glucometers often underestimate blood glucose at low values to ensure diabetic patients eat.
360
How are hand held glucometers affected by PCV changes?
Hand held glucometers are affected by PCV changes, with higher PCV's reading lower values due to less serum present.
361
What is a readily available method to measure urea concentrations for practices without biochemistry machines?
Dipstick methods or some blood gas machines can be used to measure urea concentrations.
362
What should be done if poor tissue perfusion is suspected in a patient with renal failure?
If poor tissue perfusion is suspected, a large bore i/v catheter should be placed and balanced electrolyte solution should be administered.
363
How should the patient be hydrated in cases of renal failure?
The patient should be slightly over hydrated with a CVP of 8-10cm H2O to encourage and maintain diuresis.
364
What should be monitored for pulmonary edema in cases of renal failure?
Pulmonary edema should be monitored if the patient is over hydrated.
365
How should renal failure be treated for underlying causes like ethylene glycol toxicity?
Ethylene glycol toxicity should be treated with an inhibitor of alcohol dehydrogenase or i/v ethanol or vodka.
366
What should be monitored to assess the success of treating renal failure?
Urine output should be monitored to assess the success of treating renal failure.
367
What should be considered if urinary catheter placement is not possible in a patient with renal failure?
Weighting the bedding or patient can be considered if urinary catheter placement is not possible.
368
What should be monitored to maintain adequate blood pressure in renal failure patients?
Blood pressure should be monitored to keep mean blood pressure above 60mmHg.
369
How should hyperkalemia be treated in patients with renal failure?
Hyperkalemia can be treated with i/v calcium, insulin/dextrose, or bicarbonate.
370
What is the most pressing electrolyte abnormality in cases of renal failure?
The most pressing electrolyte abnormality is hyperkalemia and hypocalcemia.
371
When should diuretics be considered in treating renal failure?
Diuretics should only be used when the patient is well hydrated and once blood pressure is stabilized.
372
What is the dosing regimen of frusemide for treating renal failure?
Frusemide can be given as a 1-4mg/kg i/v dose every 4-6 hours.
373
How can urine production be improved in renal failure patients?
Urine production can be improved with frusemide or mannitol.
374
What is an alternative diuretic to frusemide for treating renal failure in cats?
Fenoldopam has been noted to improve renal perfusion in cats with renal failure.
375
When should a second dose of frusemide be given for treating renal failure?
A second dose of frusemide can be given if no further improvement is seen after the first dose.
376
What is the precaution for using Mannitol as a diuretic in renal failure patients?
Mannitol should be used with caution in already volume overloaded anuric patients.
377
What is a secondary effect of Mannitol when used as a diuretic?
Mannitol improves vascular flow and acts as a free radical scavenger.
378
What is the dosing regimen for Mannitol as a diuretic in renal failure patients?
Mannitol can be given as a 0.5-1g bolus over 20 minutes.
379
What should be monitored closely when using Dopamine as a treatment for renal failure?
Blood pressure and an ECG should be monitored closely when using Dopamine.
380
What other drug combination is most effective when using Dopamine as a treatment for renal failure?
Dopamine is most effective when combined with a frusemide CRI.
381
What toxins can be removed by Peritoneal dialysis in cases of renal failure?
Peritoneal dialysis can remove dialyzable toxins like ethylene glycol or salicylates.
382
What are the life-threatening situations that require alteration in fluid therapy and emergency treatment?
Serious electrolyte abnormalities can be life-threatening and require alteration in fluid therapy and emergency treatment.
383
What type of samples yield useful information regarding acid-base status?
Venous samples yield useful information regarding acid-base status.
384
Where are arterial blood samples commonly taken from to investigate oxygenation status?
Arterial blood samples are commonly taken from the dorsal pedal artery in the hindlimb.
385
What does Appendix 1 in the course notes contain?
Appendix 1 contains a detailed account of acid-base analysis.
386
What can lactate measurement help in assessing?
Lactate measurement can help in assessing tissue perfusion and anaerobic metabolism.
387
What is oxygen content (CaO2) in the blood?
The total amount of oxygen carried in the blood, approximately 98-99% bound to haemoglobin and 1-2% dissolved in the plasma.
388
How is CaO2 calculated?
CaO2 = (1.34 x Hg x SaO2) + (PaO2 x 0.003)
389
What is the binding capacity of haemoglobin?
1.34
390
What is the solubility constant for O2 dissolved in plasma?
0.003
391
How does acid-base disturbances affect blood pH?
Physiological compensation occurs to return the pH towards normal.
392
What are the physiological compensatory processes in acid-base disturbances?
Respiratory and renal changes occur to compensate for acid-base changes.
393
How do respiratory and metabolic components interact in acid-base disturbances?
A change in either component will normally produce a change in the other component.
394
Which component can compensate more quickly in acid-base disturbances?
The lungs can help compensate very quickly by changing the minute volume and altering the Henderson-Hasselbalch equation in a matter of minutes.
395
Which component takes longer to compensate in acid-base disturbances?
The kidneys compensate much slower, starting after a few hours but needing up to 4-5 days for full compensation.
396
What is the purpose of calculating the anion gap?
To determine the true metabolic status and detect lactate acidosis.
397
What is an early indicator of lactate acidosis?
An elevated anion gap.
398
What is the theoretical anion gap a measure of?
The charge difference between the most common anions (Na+/K+) and the most common cations (HCO3/Cl).
399
How can the equation for anion gap be rearranged?
Unmeasured Cations - Unmeasured Anions = (Na+ + K+) - (Cl- + HCO3-)
400
What does the anion gap actually measure?
The difference in unmeasured anions and cations.
401
What are the effects of storing samples in anaerobic conditions?
There will be very little changes in PO2/PCO2 and pH up to 4-6 hours.
402
What are the changes in gas tensions due to cell metabolism?
Decrease in PO2 by leukocytes and reticulocytes, and production of CO2 by red cells through anaerobic glycolysis.
403
How does temperature affect blood gas values?
Hypothermia results in elevated pH and decreased PO2 and PCO2. Hyperthermia has the reverse effect.
404
What are the changes in blood gas values for every 1°C decrease in body temperature?
pH increases by 0.015, PaO2 decreases by 4.4%, and PCO2 decreases by 7.2%.
405
How do normal values differ between canine and feline arterial/venous blood gas and acid-base status?
Canine: pH (7.35-7.45), PO2 (90-100), PCO2 (35-45), HCO3 (20-24). Feline: pH (7.34 ± 0.1), PO2 (102.9 ± 15), PCO2 (33.6 ± 7), HCO3 (17.5 ± 3).
406
What are acidic substances and bases?
Acidic substances donate hydrogen ions, while bases accept them.
407
What are buffers and their role in preventing pH changes?
Buffers are weak acids or bases that help maintain pH stability.
408
What is pH and how is it measured?
pH is a measure of acidity or alkalinity and is derived from the Henderson-Hasselbalch equation.
409
How is pH controlled by the ratio of HCO3 to CO2?
Buffers, such as bicarbonate, control the ratio and thus determine pH.
410
What role does the respiratory system play in pH regulation?
It regulates pH by eliminating CO2.
411
How does the renal system regulate acid-base balance?
It retains or excretes H+ and HCO3 to maintain balance.
412
What is the impact of the liver in acid-base balance?
It metabolizes lactate and other organic acids.
413
When is acidosis and alkalosis present based on blood pH?
Acidosis when pH < 7.35, alkalosis when pH > 7.45.
414
What are the 4 basic types of pH disturbance?
Metabolic acidosis, metabolic alkalosis, respiratory acidosis, respiratory alkalosis.
415
What does PaCO2 measure and how does it relate to ventilation?
PaCO2 measures CO2 dissolved in arterial plasma and reflects ventilation balance.
416
What are the common causes of respiratory acidosis and alkalosis?
Acidosis: anesthesia, COPD, brain injuries, obesity. Alkalosis: fever, shock, hypoxia, left to right shunting.
417
How does PaCO2 levels change in respiratory acidosis and alkalosis?
Acidosis: PaCO2 > 45mmHg. Alkalosis: PaCO2 < 35mmHg.
418
What is the role of renal retention in controlling serum bicarbonate?
Renal retention helps control serum bicarbonate concentrations.
419
What should be given to a patient who worsens before completing the ACTH stimulation test?
0.2-0.4mg/kg dexamethasone i/v.
420
How should hypoglycaemia be treated in these patients?
Supplement fluids to 2.5-5% glucose.
421
What is the recommended dose of i/v hydrocortisone?
2-4mg/kg BID.
422
What is the purpose of the ACTH stimulation test?
For definitive diagnosis.
423
Which medication can provide glucocorticoid support without interacting with the cortisol assay?
Dexamethasone.
424
What should be given to treat hyperkalaemia if an arrhythmia is present?
Calcium gluconate 10%.
425
What is the initial dose of desoxycorticosterone pivalate (Zycortal) for mineralocorticoid supplementation?
2.2mg/kg s/c q 25 days.
426
What other medication can be used for mineralocorticoid supplementation if Zycortal is not available?
Fludrocortisone.
427
How should the dose of mineralocorticoid supplementation be adjusted?
As per manufacturer's guidelines.
428
What is the initial dose of prednisolone for glucocorticoid supplementation?
0.2mg/kg/day.
429
At what rate should sodium be corrected to avoid irreversible demyelination?
No faster than 0.5mmol/l/hour.
430
What fluid of choice should be used to restore body sodium content?
0.9% NaCl.
431
What is the formula to estimate the change in serum [Na+] with different fluid types?
Change in serum [Na+] = Infusate [Na+] - Serum [Na+] / [Body weight (kg) x 0.6] + 1.
432
What is the sodium content of 0.9% NaCl?
154 mmol/l.
433
At what serum sodium level is hyponatraemia not usually clinically significant?
Below 130mmol/l.
434
What is the normal range of serum osmolarity in dogs?
290-310mOsm/kg.
435
What is the normal range of serum osmolarity in cats?
290-330mOsm/kg.
436
What is the main determine of serum osmolarity?
Sodium.
437
What are the clinical signs of hyponatraemia?
Lethargy, depression, coma, and nausea.
438
What does hyponatraemia lead to in the brain?
Cerebral oedema.
439
What is the fluid of choice to treat hyponatraemia?
0.9% NaCl.
440
What can cause deviation between calculated and measured osmolarity?
Presence of an unmeasured osmolyte such as ethylene glycol toxicity.
441
What controls sodium balance in the body?
Thirst, ADH, and aldosterone.
442
What are the differential diagnoses for hyponatraemia?
Normal plasma osmolarity, hyperlipidaemia, hyperproteinaemia, hyperglycaemia, mannitol infusion, severe liver disease, congestive heart failure, renal failure/nephrotic syndrome, psychogenic polydipsia, syndrome of inappropriate ADH secretion, hypotonic fluid infusion, gastrointestinal loss (vomiting/diarrhea), and third space.
443
When is hyponatraemia usually clinically significant?
When sodium drops below 130mmol/l.
444
What can a rapid decrease in serum osmolarity due to hyponatraemia lead to?
Cerebral oedema.
445
How should sodium be corrected if the brain has compensated for hyponatraemia by losing osmoles?
No faster than 0.5mmol/l/hour.
446
What condition can occur if sodium is elevated too quickly in hyponatraemia treatment?
Central pontine myelinolysis.
447
What is the sodium content of Hartmann's solution?
130 mmol/l.
448
How long do the effects of calcium infusion typically last?
20-30 minutes.
449
During calcium infusion, what should be monitored to check for calcium induced arrhythmias?
ECG.
450
How can potassium excretion be enhanced in situations without renal impairment?
By intravenous fluid therapy.
451
What is a useful tool for preventing volume overload in situations with renal impairment?
Measurement of CVP.
452
Which fluid is classically the fluid of choice for intravenous therapy?
Normal saline (0.9%).
453
What are the benefits of using balanced electrolyte solutions like Hartmann's?
Reduced potassium levels and buffering effects of bicarbonate in the presence of acidosis.
454
By using insulin intravenously, how does it help reduce serum potassium levels?
It promotes cellular uptake of potassium.
455
What is the recommended dose of neutral insulin for reducing serum potassium levels?
0.25-0.5 IU.
456
What is the recommended dose of glucose per IU insulin injected?
2g.
457
How can sodium bicarbonate promote cellular uptake of potassium?
By exchanging hydrogen ions for potassium in response to alkalosis induced by bicarbonate ions.
458
What is the recommended rate of slow infusion for sodium bicarbonate?
1 mmol/kg over 10-15 minutes.
459
What are the two membrane potentials of excitable tissue affected by serum calcium and potassium?
Resting potential by potassium and threshold potential by calcium.
460
What are some differential diagnoses for hyperkalaemia?
Pseudo hyperkalaemia, thrombocytosis, haemolysis, increased intake, iatrogenic over-supplementation, translocation, acute mineral acidosis, insulin deficiency, acute tumour lysis syndrome, parental nutrition solutions, drugs, decreased renal loss.
461
What are some drugs that can cause hyperkalaemia?
Non-specific beta blockers, cardiac glycosides, ACE inhibitors, heparin, potassium sparing diuretics, NSAIDs.
462
What is the initial management for a blocked cat?
Place i/v catheter and administer a bolus of balanced electrolyte solution if poor tissue perfusion is suspected.
463
What should be considered in the management of a blocked cat?
Treating hyperkalaemia, obtaining blood for an emergency database, analyzing the ECG, placement of urinary catheter, therapeutic cystocentesis.
464
What can be used to treat hyperkalaemia in a blocked cat?
Calcium gluconate 10%, insulin, glucose saline infusion, sodium bicarbonate.
465
What is the recommended dose of calcium gluconate for treating hyperkalaemia in a blocked cat?
50-100mg/kg.
466
What is the recommended dose of insulin for treating hyperkalaemia in a blocked cat?
0.25-0.5IU/kg.
467
What should be done once the cardiovascular status of a blocked cat is more stable?
Place a urinary catheter and consider therapeutic cystocentesis.
468
What are the management steps for hypoadrenocorticism?
Place i/v catheter, collect blood for emergency database, start intravenous fluid therapy, reassess perfusion status, place a second catheter in large animals, monitor CVP.
469
What fluids are recommended for intravenous fluid therapy in hypoadrenocorticism?
Balanced electrolyte containing fluid like Hartmann's.
470
What should be considered for longer term management in hypoadrenocorticism?
Increased water intake and dietary changes.
471
What should be done if catheterization is not successful in a blocked cat?
Therapeutic cystocentesis should be considered.
472
What are possible consequences following post-obstruction diuresis in a blocked cat?
Hypokalaemia and rapid fall in BUN levels.
473
What is the normal BMBT time for a cat?
Approximately 1-2½ minutes.
474
What is the normal BMBT time for a dog?
Approximately 1½ - 4½ minutes.
475
What primary factors does primary hemostasis rely on?
Normal platelet numbers, normal platelet function, and von Willebrand's factor.
476
How can platelet numbers be checked?
By routine hematology and examining a fresh blood smear.
477
How is the blood smear checked for platelet numbers?
By looking for platelet clumps and counting the platelets per field in the mono layer behind the feathered edge.
478
What is the equivalent platelet count in a mono layer behind the feathered edge for one platelet per x100 field?
Approximately 15x109/l platelets.
479
How can platelet function and von Willebrand's factor levels be assessed?
By performing the buccal mucosal bleeding time (BMBT).
480
What should be checked first before performing the BMBT?
Platelet numbers.
481
How is the BMBT performed?
By making an incision on the oral mucosa with a standard device like the Simplate II®.
482
What is the treatment for von Willebrand's Disease?
Administering FFP (10-20ml/kg) or cryoprecipitate to replenish vWF to stop bleeding, or giving FFP/Cryoprecipitate when bleeding might be expected.
483
What is the recommended dose of desmopressin (DDAVP) for helping release vWF from endothelial stores?
1μg/kg s/c.
484
What is secondary hemostasis dependent on?
Adequate levels of coagulation factors to allow stabilization of the platelet plug by a fibrin mesh.
485
What is the purpose of the whole blood coagulation time (WBCT)?
To assess both the extrinsic and common pathways.
486
How is the WBCT performed?
By taking blood into a warm glass tube and tilting it every 30 seconds until it clots.
487
What is the purpose of the activated clotting time (ACT)?
To examine the extrinsic and common pathways using a commercial tube with a clay activator.
488
What is the normal clotting time for cats in the ACT test?
Within 50-75 seconds.
489
What is the normal clotting time for dogs in the ACT test?
Within 60-120 seconds.
490
Where can more detailed coagulation times be run?
At external laboratories or on bedside analyzers like the Idexx Coag DX®.
491
What does the prothrombin time (PT) investigate?
The extrinsic pathways of coagulation.
492
What does the activated partial thromboplastin time (aPTT) investigate?
The intrinsic pathway of coagulation.
493
What type of blood samples are used for PT and aPTT tests?
Citrated blood samples.
494
What test results are considered abnormal for PT and aPTT?
>25% greater than the control samples.
495
What is the most common acquired coagulation defect?
Anticoagulant rodenticide toxicity.
496
What causes anticoagulant rodenticide toxicity?
Toxins blocking the conversion of vitamin K-dependent epoxide reductase.
497
Which factors' activation does anticoagulant rodenticide toxicity block?
Factors II, VII, IX, and X.
498
What is the half-life of factor VII?
6 hours.
499
What will be elevated before the APTT in anticoagulant rodenticide toxicity?
PT (prothrombin time).
500
What term describes proteins induced by vitamin K antagonism in anticoagulant rodenticide toxicity?
PIVKA's (Proteins Induced by Vitamin K Antagonism).
