15- Post operative Explains Flashcards
What is the definition of postoperative cognitive dysfunction (POCD)?
Deterioration in performance in a battery of neuropsychological tests that would be expected in less than 3.5% of controls, or long-term, possibly permanent disabling deterioration in cognitive function following surgery.
What factors are associated with late POCD?
Increasing age, emboli, and biochemical disturbances.
What factors are associated with early POCD?
Increasing age, general anesthesia rather than regional anesthesia, longer duration of anesthesia, reoperation, and postoperative infection.
How are patients identified as malnourished according to NICE guidelines?
Patients with a BMI < 18.5 kg/m² or unintentional weight loss of > 10% over 3-6 months, or patients with a BMI < 20 kg/m² and unintentional weight loss of > 5% over 3-6 months.
Who is considered at risk of malnutrition according to NICE guidelines?
Patients who have eaten nothing or very little for more than 5 days and are likely to continue eating little for another 5 days, or patients with poor absorptive capacity, high nutrient losses, or high metabolism.
When should parenteral nutrition be considered according to NICE guidelines?
Parenteral nutrition should be considered in patients with unsafe or inadequate oral intake, or in patients with a non-functional gastrointestinal tract, perforation, or inaccessibility.
What is the recommended approach for feeding patients for less than 14 days?
Feeding via a peripheral venous catheter is recommended for patients needing parenteral nutrition for less than 14 days.
What is the recommended approach for feeding patients for more than 30 days?
A tunneled subclavian line is recommended for patients needing parenteral nutrition for more than 30 days.
In what situations is continuous administration of parenteral nutrition recommended?
Continuous administration is recommended for severely unwell patients.
When should a change from continuous to cyclical feeding be considered?
If parenteral nutrition is needed for more than 2 weeks, a change from continuous to cyclical feeding should be considered.
What is the recommended approach for unwell patients in the first 24-48 hours of parenteral nutrition?
Do not give more than 50% of the daily regimen to unwell patients in the first 24-48 hours.
What is the recommendation for perioperative parenteral feeding in surgical patients?
In malnourished surgical patients with an unsafe swallow or a non-functional gastrointestinal tract, perforation, or inaccessibility, perioperative parenteral feeding should be considered.
What is circulatory support in the context of critically ill patients?
Circulatory support is provided to patients who have impaired tissue oxygenation, often as a result of circulatory shock.
What are some methods of haemodynamic monitoring for patients requiring circulatory support?
Methods of haemodynamic monitoring include regular urine output measurements, blood pressure monitoring, ECG monitoring for cardiac arrhythmias, and pulse oximeter measurements for estimating hemoglobin oxygen saturation.
How is invasive arterial blood pressure monitoring performed?
Invasive arterial blood pressure monitoring is done using an indwelling arterial line, most commonly placed in the radial artery. Care should be taken not to cannulate end arteries.
What is central venous pressure (CVP) and how is it measured?
Central venous pressure represents right atrial filling pressure and volume status. It is measured using a CVP line typically placed in the superior vena cava via the internal jugular route. A fluid challenge can be used to assess response, with a prolonged rise in CVP indicating adequate intravascular volume.
What is the purpose of a Swan-Ganz catheter in circulatory support?
A Swan-Ganz catheter, traditionally inserted to monitor cardiac output, provides information on left ventricular preload, pulmonary artery occlusion pressure, left atrial pressure, stroke volume, systemic vascular resistance, pulmonary artery resistance, and oxygen delivery and consumption.
When would vasoactive drugs be considered in circulatory support?
Vasoactive drugs may be considered in patients with ongoing circulatory compromise despite adequate circulating volume. These drugs are typically administered via the central venous route.
What are some commonly used inotropes in circulatory support and their effects?
Commonly used inotropes include noradrenaline (α agonist with vasopressor action), adrenaline (α and β receptor agonist that increases cardiac output and peripheral vascular resistance), dopamine (β1 agonist that increases contractility and heart rate), dobutamine (β1 and β2 agonist that increases cardiac output and decreases systemic vascular resistance), and milrinone (phosphodiesterase inhibitor that improves muscular contractility and acts as a vasodilator).
What does the pulmonary artery occlusion pressure (PAOP) measure?
The pulmonary artery occlusion pressure is an indirect measure of the left atrial pressure and the filling pressure of the left heart.
How is the most accurate trace of the pulmonary artery occlusion pressure obtained?
The most accurate trace is obtained by inflating the balloon at the tip of the catheter and occluding the vessel.
What is the significance of the pulmonary artery end diastolic pressure measurement?
If it is not possible to occlude the vessel, the measurement obtained will be the pulmonary artery end diastolic pressure.
How is the pulmonary artery occlusion pressure interpreted?
A normal pulmonary artery occlusion pressure is 8-12 mmHg. A low pressure (<5 mmHg) indicates hypovolemia, while a low pressure with pulmonary edema indicates ARDS. A high pressure (>18 mmHg) suggests overload.
What additional measurements can help accurately classify patients when combined with the pulmonary artery occlusion pressure?
When combined with measurements of systemic vascular resistance and cardiac output, it is possible to accurately classify patients.
How is systemic vascular resistance (SVR) derived?
Systemic vascular resistance is derived from the mean aortic pressure, mean right atrial pressure, and cardiac output using the formula: SVR = 80(mean aortic pressure - mean right atrial pressure) / cardiac output.
What is total parenteral nutrition (TPN) commonly used for?
TPN is commonly used in nutritionally compromised surgical patients.
What components are found in TPN bags?
TPN bags contain combinations of glucose, lipids, and essential electrolytes.
How is the exact composition of TPN determined?
The exact composition of TPN is determined based on the patient’s nutritional requirements.
What are the potential complications associated with peripheral infusion of TPN?
Peripheral infusion of TPN may result in thrombophlebitis.
Where should longer-term infusions of TPN be administered?
Longer-term infusions of TPN should be administered into a central vein, preferably via a PICC line.
What are some complications associated with TPN?
Complications related to TPN include sepsis, re-feeding syndromes, and hepatic dysfunction.
What are the indications for IV fluids in paediatric patients?
Indications for IV fluids include resuscitation and circulatory support, replacing ongoing fluid losses, maintenance fluids for children who cannot consume oral fluids, and correction of electrolyte disturbances.
Which fluids should be avoided in children outside the neonatal period?
In children outside the neonatal period, saline/glucose solutions should not be given, especially saline 0.18/glucose 4% solutions. The report suggests that 0.45% saline/5% glucose may be used, but preference should be given to isotonic solutions.
What type of fluid should neonates receive during surgery?
Neonates should receive glucose 10% during surgery.
What are the recommended daily water and electrolyte requirements for maintenance fluids based on body weight?
For the first 10kg of body weight, the water requirement is 100ml/kg/day, sodium requirement is 2-4 mmol/kg/day, and potassium requirement is 1.5-2.5 mmol/kg/day. For the second 10kg of body weight, the water requirement is 50ml/kg/day, sodium requirement is 1-2 mmol/kg/day, and potassium requirement is 0.5-1.5 mmol/kg/day. For subsequent kilograms of body weight, the water requirement is 20ml/kg/day, sodium requirement is 0.5-1.0 mmol/kg/day, and potassium requirement is 0.2-0.7 mmol/kg/day.
Which fluids are recommended for use in paediatric patients?
Recommended fluids include 0.9% saline, 5% glucose (only with saline for maintenance and not to replace losses), and Hartmann’s solution.
When should potassium be added to maintenance fluids, and how should it be monitored?
Potassium should be added to maintenance fluids based on the patient’s plasma potassium levels, which should be monitored.
What type of fluid should other children receive during surgery?
Other children should receive isotonic crystalloid during surgery.
How much glucose is typically given to neonates for maintenance?
Neonates typically receive 10% glucose at a rate of 60ml/kg/day.
What are acute transfusion reactions?
Acute transfusion reactions are adverse signs or symptoms that occur during or within 24 hours of a blood transfusion.
What are the most frequent reactions in acute transfusion reactions?
The most frequent reactions in acute transfusion reactions are fever, chills, pruritus, or urticaria. These symptoms typically resolve promptly without specific treatment or complications.
What signs may indicate a potentially fatal reaction during a blood transfusion?
Severe dyspnea, pyrexia, or loss of consciousness occurring in temporal relationship with a blood transfusion may be the first indication of a more severe potentially fatal reaction.
What are the proposed mechanisms underlying transfusion-related lung injury?
There are two proposed mechanisms for transfusion-related lung injury. One involves the sequestration of primed neutrophils within the recipient pulmonary capillary bed. The other mechanism suggests that HLA mismatches between donor neutrophils and recipient lung tissue are to blame.
What are the causes of adverse transfusion reactions?
The causes of adverse transfusion reactions are multi-factorial. Immune-mediated reactions can occur due to component mismatch, often caused by clerical error. Non-immune mediated complications may occur due to product contamination, which can be bacterial or viral.
What are some examples of immune-mediated transfusion reactions?
Immune-mediated transfusion reactions include alloimmunization, thrombocytopenia, transfusion-associated lung injury, graft vs host disease, acute or delayed hemolysis, ABO incompatibility, and Rhesus incompatibility.
What are some examples of non-immune mediated transfusion reactions?
Non-immune mediated transfusion reactions include hypocalcemia, congestive heart failure (CCF), infections, and hyperkalemia.
What are the characteristics of an oropharyngeal airway?
Oropharyngeal airways are easy to insert and use, do not require paralysis, are ideal for very short procedures, and are often used as a bridge to a more definitive airway.
What are the characteristics of a tracheostomy?
A tracheostomy reduces the work of breathing and dead space. It may be useful in slow weaning. Percutaneous tracheostomy is widely used in the intensive care unit (ITU). Tracheostomy tends to dry secretions, so humidified air is usually required.
What are the characteristics of a laryngeal mask?
Laryngeal masks are widely used, very easy to insert, sit in the pharynx and align to cover the airway, but provide poor control against reflux of gastric contents. Paralysis is not usually required. They are commonly used for a wide range of anaesthetic uses, especially in day surgery, but are not suitable for high-pressure ventilation.
What is the main advantage of an oropharyngeal airway?
The main advantage of an oropharyngeal airway is that it is easy to insert and use.
What are the characteristics of an endotracheal tube?
An endotracheal tube provides optimal control of the airway once the cuff is inflated. It can be used for long or short-term ventilation. Errors in insertion can result in esophageal intubation, so end-tidal CO measurement is usually performed. Paralysis is often required, and higher ventilation pressures can be used.
What is a disadvantage of a laryngeal mask?
A disadvantage of a laryngeal mask is that it provides poor control against reflux of gastric contents.
When is a tracheostomy commonly used?
A tracheostomy is commonly used in the intensive care unit (ITU) and may be useful in slow weaning.
What is an important consideration when using an endotracheal tube?
When using an endotracheal tube, it is important to measure end-tidal CO to detect any potential esophageal intubation.
Why is paralysis often required with an endotracheal tube?
Paralysis is often required with an endotracheal tube to provide optimal control of the airway.
What is a limitation of a laryngeal mask?
A limitation of a laryngeal mask is that it is not suitable for high-pressure ventilation, although a small amount of PEEP (positive end-expiratory pressure) may be possible.
What is the definition of sepsis?
Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection.
What is the purpose of the Sequential (Sepsis-Related) Organ Failure Assessment Score (SOFA)?
The SOFA score helps identify and categorize patients with sepsis by grading abnormality by organ system and accounting for clinical interventions.
What are the criteria used in the SOFA score?
The SOFA score includes criteria such as PaO2/FIO2 ratio, platelet count, bilirubin level, mean arterial pressure (MAP), Glasgow Coma Scale (GCS), creatinine level, and urine output.
What does a SOFA score of 2 or more indicate?
A SOFA score of 2 or more reflects an overall mortality risk of approximately 10% in a general hospital population with suspected infection.
What is the purpose of the qSOFA score?
The qSOFA score is a bedside prompt that helps identify patients with suspected infection who are at greater risk for a poor outcome outside the intensive care unit (ICU).
What are the criteria used in the qSOFA score?
The qSOFA score includes criteria such as respiratory rate (>22 breaths per minute), altered mentation (Glasgow Coma Scale <15), and systolic blood pressure (<100 mmHg).
How can septic shock be identified?
Septic shock can be identified by a clinical construct of sepsis with persisting hypotension requiring vasopressors to maintain a mean arterial pressure (MAP) of 65 mmHg and having a serum lactate level >2 mmol/L (18mg/dL) despite adequate volume resuscitation.
What are the resuscitation goals for patients with septic shock?
The resuscitation goals for patients with septic shock include a central venous pressure (CVP) of 8-12 mmHg, a MAP >65 mmHg, urine output >0.5 ml/kg per hour, and a superior vena cava oxygen saturation >70%.
What is considered a normal lactate level?
A normal lactate level is considered to be within the normal range. 0.5 to 2.2 mmol/L.
What is the parameter and corresponding scores for PaO2/FIO2 ratio?
PaO2/FIO2 ratio: >400 (score 0), <400 (score 1), <300 (score 2), <200 (score 3), <100 (score 4).
What is the parameter and corresponding scores for platelet count?
Platelets x10 microliters: >150 (score 0), <150 (score 1), <100 (score 2), <50 (score 3), <20 (score 4).
What is the parameter and corresponding scores for bilirubin level?
Bilirubin micro Mol/L: 20 (score 0), 20-32 (score 1), 33-101 (score 2), 102-204 (score 3), >204 (score 4).
What is the parameter and corresponding scores for cardiovascular (MAP)?
Cardiovascular (MAP): >70 mmHg (score 0), MAP 70 mmHg (score 1), Dopamine <5 or dobutamine (any dose) (score 2), Dopamine 5.1-15 or epinephrine 0.1 or norepinephrine 0.1 (score 3), Dopamine >15 or epinephrine >0.1 or norepinephrine >0.1 (score 4).
What is the parameter and corresponding scores for Glasgow Coma Scale (GCS)?
GCS: 15 (score 0), 13-14 (score 1), 10-12 (score 2), 6-9 (score 3), <6 (score 4).
What is the parameter and corresponding scores for creatinine level?
Creatinine micro mol/L: <110 (score 0), 110-170 (score 1), 171-299 (score 2), 300-440 (score 3), >440 (score 4).
What is the parameter and corresponding scores for urine output?
Urine output ml/day: >500 (score 0), >500 (score 1), >500 (score 2), <500 (score 3), <200 (score 4).
What is the mechanism of action of Suxamethonium?
It inhibits the action of acetylcholine at the neuromuscular junction.
How is Suxamethonium degraded in the body?
It is degraded by plasma cholinesterase and acetylcholinesterase.
How does Suxamethonium compare to other muscle relaxants in terms of onset and duration of action?
It has the fastest onset and shortest duration of action among all muscle relaxants.
What is the effect of Suxamethonium prior to paralysis?
It produces generalized muscular contraction.
What are some adverse effects of Suxamethonium?
Hyperkalemia, malignant hyperthermia, and delayed recovery.
What is von Willebrand’s disease?
It is the most common inherited bleeding disorder.
What causes von Willebrand’s disease?
Mutations in the gene for von Willebrand factor.
What is the role of von Willebrand factor?
It promotes platelet adhesion to damaged endothelium and other platelets, as well as the transport and stabilization of factor VIII.
How many subtypes of von Willebrand’s disease are there?
There are 7 subtypes.
Which subtype of von Willebrand’s disease is the most common?
Type I, which is autosomal dominant and accounts for 80% of cases.
What is the typical diagnostic test for von Willebrand’s disease?
The bleeding time test.
What are the treatment options for von Willebrand’s disease?
Tranexamic acid for minor cases and minor procedures. DDAVP is effective for more significant bleeding or procedures, but less effective in type 2 and contraindicated in type 2B. Patients with type 3 do not respond to DDAVP and usually receive factor VIII concentrates containing vWF.
What is the spectrum of severity in von Willebrand’s disease?
It ranges from spontaneous bleeding and epistaxis to troublesome excessive bleeding following minor procedures.
What is Adult Respiratory Distress Syndrome (ARDS)?
It is an acute condition characterized by bilateral pulmonary infiltrates and severe hypoxemia (PaO2/FiO2 ratio < 200) without evidence of cardiogenic pulmonary edema.
How is ARDS subdivided?
ARDS is subdivided into two stages: an exudative phase of injury with associated edema in the early stages, followed by a repair phase with fibroproliferative changes in the later stage.
What are the clinical features of ARDS?
Clinical features of ARDS include acute dyspnea and hypoxemia hours to days after the initial event, multi organ failure, and rising ventilatory pressures.
What are some causes of ARDS?
Common causes of ARDS include sepsis, direct lung injury, trauma, acute pancreatitis, long bone fracture or multiple fractures (through fat embolism), and head injury.
What is the management approach for ARDS?
The management of ARDS involves treating the underlying cause, administering antibiotics if signs of sepsis are present, maintaining a negative fluid balance with diuretics, using recruitment maneuvers such as prone ventilation and positive end-expiratory pressure, and implementing a mechanical ventilation strategy with low tidal volumes to prevent lung injury.
What is the only treatment found to improve survival rates in ARDS?
Using low tidal volumes in mechanical ventilation is the only treatment found to improve survival rates in ARDS.
What is malignant hyperthermia?
Malignant hyperthermia is a condition that occurs following the administration of certain anesthetic agents, with an incidence rate of approximately 1 in 15,000. It is characterized by hyperpyrexia (high fever) and muscle rigidity.
What is the cause of malignant hyperthermia?
Malignant hyperthermia is caused by an excessive release of calcium from the sarcoplasmic reticulum of skeletal muscle. This is associated with defects in a gene on chromosome 19 that encodes the ryanodine receptor, which controls calcium release from the sarcoplasmic reticulum.
Which agents are associated with malignant hyperthermia?
Malignant hyperthermia can be caused by the administration of halothane and suxamethonium. Other drugs, such as antipsychotics, can also cause a similar condition known as neuroleptic malignant syndrome.
What investigations can be performed for malignant hyperthermia?
Elevated levels of creatine kinase (CK) can be observed in the blood. Contracture tests with halothane and caffeine can also be performed.
What is the management approach for malignant hyperthermia?
The administration of dantrolene is the primary management approach for malignant hyperthermia. Dantrolene works by preventing the release of calcium from the sarcoplasmic reticulum.
How often should weight be monitored according to NICE guidelines for nutrition monitoring?
Weight should be monitored daily if there are concerns about fluid balance. Otherwise, it should be monitored weekly, reducing to monthly.
What can be measured if weight cannot be obtained for nutrition monitoring?
If weight cannot be obtained, mid-arm circumference or triceps skinfold thickness can be measured monthly.
When should BMI be measured according to NICE guidelines?
BMI should be measured at the start of feeding and then monthly.
How often should electrolyte levels be monitored according to NICE guidelines?
Electrolyte levels should be monitored daily until they stabilize, and then once or twice a week.
Which laboratory tests should be performed weekly if stable, according to NICE guidelines?
If stable, weekly tests should include glucose, phosphate, magnesium, liver function tests (LFTs), calcium, albumin, full blood count (FBC), and mean corpuscular volume (MCV).
Which laboratory tests should be performed 2-4 weekly if stable, according to NICE guidelines?
If stable, tests such as zinc, folate, vitamin B12, and copper levels should be performed 2-4 weekly.
How often should iron and ferritin levels be monitored for nutrition monitoring?
Iron and ferritin levels should be monitored every 3-6 months. If on a home parenteral regime, manganese levels should also be monitored.
How often should vitamin D levels be monitored according to NICE guidelines?
Vitamin D levels should be monitored every 6 months.
When should bone densitometry be performed for nutrition monitoring?
Bone densitometry should be initially performed when starting home parenteral nutrition and then repeated every 2 years.
What are extrapyramidal side effects?
Extrapyramidal side effects are adverse effects that can occur with anti-dopaminergic drugs, such as antipsychotics. They can range from mild parkinsonian symptoms like resting tremor and bradykinesia to acute dystonic reactions characterized by abnormal and involuntary facial and bodily movements, such as spasmodic torticollis, oculogyric crisis, and oromandibular dystonia.
Where are chronic cases of acute dystonic reactions commonly encountered?
Chronic cases of acute dystonic reactions are generally encountered in psychiatric units.
In what scenario can the administration of the anti-dopaminergic drug metoclopramide precipitate an attack of acute dystonic reaction?
In surgical practice, the administration of the anti-dopaminergic drug metoclopramide may be sufficient to precipitate an attack of acute dystonic reaction.
What treatment options are available for acute dystonic reactions if symptoms are troublesome?
If symptoms of acute dystonic reactions are sufficiently troublesome, treatment may be required. Two drugs that can be used for treatment are benzhexol and procyclidine.
What is abdominal wound dehiscence?
Abdominal wound dehiscence is a significant problem that can occur after abdominal surgery. It refers to the failure of all layers of an abdominal mass closure, leading to the protrusion of viscera externally. It is associated with a mortality rate of approximately 30%.
What are the ECG features of hyperkalemia?
The ECG features of hyperkalemia include peaking of T waves (which occurs first), loss of P waves, broad QRS complexes, and the possibility of ventricular fibrillation.
What is the management approach for sudden full dehiscence of abdominal wounds?
The management approach for sudden full dehiscence of abdominal wounds includes providing analgesia, administering intravenous fluids and broad-spectrum antibiotics, covering the wound with saline-impregnated gauze, and making arrangements for a return to the operating theatre.
What are the risk factors for abdominal wound dehiscence?
Factors that increase the risk of abdominal wound dehiscence include malnutrition, vitamin deficiencies, jaundice, steroid use, major wound contamination (such as faecal peritonitis), and poor surgical technique. The preferred method for closure is the mass closure technique, also known as the Jenkins Rule.
What should be done to correct the underlying cause of abdominal wound dehiscence?
To correct the underlying cause of abdominal wound dehiscence, interventions such as total parenteral nutrition (TPN) or nasogastric (NG) feeding may be implemented if malnutrition is present. The most appropriate strategy for managing the wound should also be determined.
What are the surgical strategies for managing abdominal wound dehiscence?
The surgical strategies for managing abdominal wound dehiscence depend on the underlying cause and the condition of the wound. Options include resuturing the wound if the edges are healthy, applying a wound manager (clear dressing with removable front) when granulation tissue is present or a high-output bowel fistula is present, using a ‘Bogota bag’ as a temporary measure when the wound cannot be closed, or applying a VAC (Vacuum-Assisted Closure) dressing system with the correct layer interposed between the suction device and the bowel to prevent complications.
What is the definition of massive haemorrhage?
Massive haemorrhage is defined as the loss of one blood volume in a 24-hour period, the loss of 50% of the circulating blood volume in 3 hours, or a blood loss of 150ml/minute. In adults, the normal blood volume is approximately 7% of total body weight, while in children, it ranges between 8 and 9% of their body weight.
What are the complications of massive transfusion?
Complications of massive transfusion include hypothermia, hypocalcaemia (due to citrate anticoagulant in FFP and platelets), hyperkalaemia (due to stored red cells containing 5-10 mmol K), delayed type transfusion reactions (minor incompatibility issues, especially with urgent or non cross-matched blood), transfusion-related lung injury (acute onset non-cardiogenic pulmonary oedema, most common with plasma components), coagulopathy (platelet count drop and dilution of clotting factors), and halving of fibrinogen concentration per 0.75 blood volume transfused.
What are the key points about hypothermia as a complication of massive transfusion?
Hypothermia can occur as a complication of massive transfusion. Blood is refrigerated and hypothermic blood impairs homeostasis. It also shifts the Bohr curve to the left.
What are the key points about hypocalcaemia as a complication of massive transfusion?
Hypocalcaemia can occur as a complication of massive transfusion. Both fresh frozen plasma (FFP) and platelets contain citrate anticoagulant, which can chelate calcium.
What are the key points about hyperkalaemia as a complication of massive transfusion?
Hyperkalaemia can occur as a complication of massive transfusion. The plasma of red cells stored for 4-5 weeks contains 5-10 mmol K.
What are the key points about transfusion-related lung injury as a complication of massive transfusion?
Transfusion-related lung injury is a potential complication of massive transfusion. It is characterized by acute onset non-cardiogenic pulmonary oedema and is the leading cause of transfusion-related deaths. The greatest risk is associated with plasma components. It occurs as a result of leucocyte antibodies in transfused plasma, leading to aggregation and degranulation of leucocytes in lung tissue, which accounts for lung injury.
What is coagulopathy as a complication of massive transfusion?
Coagulopathy is a complication that can occur with massive transfusion. It is anticipated once the circulating blood volume has been transfused. It typically results in a platelet count drop to 100 or less and dilutes and does not fully replace clotting factors. The fibrinogen concentration halves per 0.75 blood volume transfused.
What are the different categories of hypovolaemia?
Hypovolaemia can be divided into three categories: overt compensated hypovolaemia, covert compensated hypovolaemia, and decompensated hypovolaemia.
Which category of hypovolaemia is the most common?
The most common category of hypovolaemia is covert compensated hypovolaemia.
What is the most useful diagnostic test for detecting covert compensated hypovolaemia?
Urinanalysis is the most useful diagnostic test for detecting covert compensated hypovolaemia. It often shows increased urinary osmolality and decreased sodium concentration.
What is the characteristic of covert compensated hypovolaemia?
Covert compensated hypovolaemia often does not show overtly discernible clinical signs, especially in class I shock. This is due to a degree of splanchnic autotransfusion.
What is the characteristic of overt compensated hypovolaemia?
In overt compensated hypovolaemia, the blood pressure is maintained, although other haemodynamic parameters may be affected. This corresponds to class II shock.
How can fluid resuscitation be guided in patients with underlying cardiopulmonary disease?
In patients with underlying cardiopulmonary disease, the placement of a central venous pressure (CVP) line can guide fluid resuscitation.
What can untreated hypovolaemia lead to?
Untreated hypovolaemia can progress to become uncompensated, leading to end organ dysfunction. Microvascular hypoperfusion can result in acidosis, which has a subsequent myocardial depressive effect, creating a vicious circle.
What is the treatment for hypovolaemia?
The treatment for hypovolaemia is intravenous fluids. A fluid challenge, such as the rapid infusion of 250ml of crystalloid, is often used as both a diagnostic and resuscitative measure. If this fails to produce the desired response, the patient needs to be re-evaluated clinically, and more fluid may be needed.
What should be considered in an anuric, normotensive patient with hypovolaemia?
In an anuric, normotensive patient with hypovolaemia, mechanical ureteric obstruction should not be overlooked as a possible cause.
What is the definition of neuropathic pain?
Neuropathic pain is pain that occurs as a result of damage or disruption to the nervous system. It is often challenging to treat and does not respond well to standard pain medications.
What are some examples of conditions that can cause neuropathic pain?
Some examples of conditions that can cause neuropathic pain include diabetic neuropathy, post-herpetic neuralgia, trigeminal neuralgia, and prolapsed intervertebral disc.
What are the first-line treatment options for neuropathic pain according to NICE guidance?
According to NICE guidance, the first-line treatment options for neuropathic pain are oral amitriptyline or pregabalin.
What should be considered if a person cannot tolerate the adverse effects of amitriptyline but experiences satisfactory pain reduction with it?
If a person cannot tolerate the adverse effects of amitriptyline but experiences satisfactory pain reduction, oral imipramine or nortriptyline can be considered as an alternative.
What should be considered for second-line treatment if the first-line treatment was with amitriptyline?
If the first-line treatment was with amitriptyline, switching to or combining it with pregabalin can be considered for second-line treatment.
What should be considered for second-line treatment if the first-line treatment was with pregabalin?
If the first-line treatment was with pregabalin, switching to or combining it with amitriptyline can be considered for second-line treatment.
What are some other options for managing neuropathic pain?
Other options for managing neuropathic pain include referral to a pain management clinic, the use of tramadol (not other strong opioids), and the application of topical lidocaine for localized pain if patients are unable to take oral medication.
Are there any variations in the NICE guidance for specific conditions?
Yes, for specific conditions such as trigeminal neuralgia, carbamazepine is used as the first-line treatment, and for diabetic neuropathy, duloxetine is used first-line.
What should be checked for in patients receiving oral nutrition?
In patients receiving oral nutrition, it is important to check for dysphagia, which is difficulty in swallowing.
What should be provided to patients with a safe swallow and adequate nutritional status?
For patients with a safe swallow and adequate nutritional status, food and fluid should be provided in adequate quantity and quality. They should be given a balanced diet.
What additional supplements should be offered to patients receiving oral nutrition?
In addition to a balanced diet, multivitamins and minerals should be offered to patients receiving oral nutrition.
When should oral intake be aimed for in malnourished surgical patients after certain surgeries?
For malnourished surgical patients who have a safe swallow and have undergone post-op caesarean, gynaecological, or abdominal surgery, oral intake should be aimed for within 24 hours.
How can malnourished patients be identified?
Malnourished patients can be identified using the following criteria: BMI less than 18.5 kg/m², unintentional weight loss of more than 10% over 3-6 months, or BMI less than 20 kg/m² with unintentional weight loss of more than 5% over 3-6 months.
Who is considered at risk of malnutrition?
Patients who have eaten little or nothing for more than 5 days and are likely to continue eating little for another 5 days, those with poor absorptive capacity, high nutrient losses, or high metabolism are considered at risk of malnutrition.
What is the final pathway in acute renal failure?
The final pathway in acute renal failure is tubular cell death.
Why is the renal medulla susceptible to renal tubular hypoxia?
The renal medulla is a relatively hypoxic environment, which makes it susceptible to renal tubular hypoxia.
What maintains renal blood flow across a range of arterial pressures?
Renovascular autoregulation maintains renal blood flow across a range of arterial pressures.
What are the best indices of the level of renal function?
Estimates of glomerular filtration rate (GFR) are the best indices of the level of renal function.
What factors can be considered to obtain useful clinical estimates of renal function?
Useful clinical estimates of renal function can be obtained by considering serum creatinine, age, race, gender, and body size.
Are eGFR calculations reliable in populations with high GFRs?
No, eGFR calculations such as the Cockcroft and Gault equation are less reliable in populations with high GFRs.
What can induce apoptosis and necrosis in the kidneys?
Nephrotoxic stimuli such as aminoglycosides and radiological contrast media can induce apoptosis, while myoglobinuria and hemolysis can result in necrosis in the kidneys.
What factors increase the likelihood of post-operative renal failure?
Post-operative renal failure is more likely to occur in patients who are elderly, have peripheral vascular disease, high BMI, have COPD, receive vasopressors, are on nephrotoxic medication, or undergo emergency surgery.
How can the risk of renal tubular damage be reduced?
Avoiding hypotension will reduce the risk of renal tubular damage.
Is there evidence that ACE inhibitors or dopamine reduce the incidence of post-operative renal failure?
No, there is no evidence that administration of ACE inhibitors or dopamine reduces the incidence of post-operative renal failure.
What can pulmonary function tests determine in respiratory diseases?
Pulmonary function tests can determine whether a respiratory disease is obstructive or restrictive.
What are the main findings in obstructive lung diseases?
In obstructive lung diseases: FEV1 (forced expiratory volume in 1 second) is significantly reduced, FVC (forced vital capacity) is reduced or normal, and FEV1% (FEV1/FVC) is reduced (less than approximately 70%).
Can you provide some examples of obstructive lung diseases?
Some examples of obstructive lung diseases include asthma, COPD (chronic obstructive pulmonary disease), bronchiectasis, and bronchiolitis obliterans.
What are the main findings in restrictive lung diseases?
In restrictive lung diseases: FEV1 is reduced, FVC is significantly reduced, and FEV1% is normal or increased (over approximately 70%).
Can you provide some examples of restrictive lung diseases?
Some examples of restrictive lung diseases include pulmonary fibrosis, asbestosis, sarcoidosis, acute respiratory distress syndrome, infant respiratory distress syndrome, kyphoscoliosis, and neuromuscular disorders.
What are the criteria for brain stem death testing?
The criteria for brain stem death testing include: deep coma of known etiology, exclusion of reversible causes, no sedation, normal electrolytes.
What are the tests performed to determine brain death?
The tests performed to determine brain death include: checking for fixed pupils that do not respond to changes in light intensity, absence of the corneal reflex, absence of oculo-vestibular reflexes (caloric test), no response to supraorbital pressure, no cough reflex or gagging response, and no observed respiratory effort after disconnection from the ventilator.
How is the absence of pupillary response tested?
The absence of pupillary response is tested by observing fixed pupils that do not respond to sharp changes in the intensity of incident light.
What is the caloric test?
The caloric test involves the slow injection of at least 50ml of ice-cold water into each ear in turn to check for the absence of eye movements (oculo-vestibular reflexes).
What reflexes are tested to determine brain stem death?
The reflexes tested to determine brain stem death include the corneal reflex, oculo-vestibular reflexes (caloric test), supraorbital pressure response, cough reflex to bronchial stimulation, and gagging response to pharyngeal stimulation.
How is respiratory effort tested in brain stem death testing?
Respiratory effort is tested by disconnecting the ventilator for a sufficient amount of time (typically 5 minutes) to ensure an increase in the arterial partial pressure of carbon dioxide. During this disconnection, pre-oxygenation and diffusion oxygenation are performed to ensure adequate oxygenation.
Who should perform the brain stem death testing?
The brain stem death testing should be performed by two appropriately experienced doctors on two separate occasions. Both doctors should have at least 5 years of post-graduate experience, with one of them being a consultant. Neither doctor can be a member of the transplant team if organ donation is being contemplated.
What is the recommended initial lung-imaging modality for non-massive pulmonary embolism (PE)?
The recommended initial lung-imaging modality for non-massive PE is computed tomographic pulmonary angiography (CTPA).
What are the advantages of CTPA compared to ventilation-perfusion (V/Q) scans?
The advantages of CTPA compared to V/Q scans include speed, easier performance out-of-hours, reduced need for further imaging, and the possibility of providing an alternative diagnosis if PE is excluded.
If the CTPA is negative, do patients need further investigations or treatment for PE?
No, if the CTPA is negative, patients do not need further investigations or treatment for PE.
When may ventilation-perfusion scanning be used initially for suspected PE?
Ventilation-perfusion scanning may be used initially if appropriate facilities exist, the chest x-ray is normal, and there is no significant symptomatic concurrent cardiopulmonary disease.
What are clinical probability scores used for?
Clinical probability scores based on risk factors and history are widely used to help decide on further investigation and management of suspected PE.
What is the sensitivity and specificity of V/Q scans in diagnosing PE?
V/Q scans have a sensitivity of 98% and specificity of 40% in diagnosing PE. However, they have a high negative predictive value, meaning that if the scan is normal, it virtually excludes PE.
What is the sensitivity and specificity of D-dimers in diagnosing PE?
D-dimers have a sensitivity of 95-98% but poor specificity in diagnosing PE.
What are some other causes of mismatch in V/Q scans?
Some other causes of mismatch in V/Q scans include old pulmonary embolisms, AV malformations, vasculitis, and previous radiotherapy.
What type of defects does COPD present in V/Q scans?
COPD presents with matched defects in V/Q scans.
What is the main disadvantage of pulmonary angiography?
Pulmonary angiography, although considered the gold standard, has a significant complication rate compared to other investigations.
How is cryoprecipitate usually transfused?
Cryoprecipitate is usually transfused as a 6 unit pool.
What is cryoprecipitate?
Cryoprecipitate is a blood product made from plasma.
What are the indications for transfusing cryoprecipitate?
The indications for transfusing cryoprecipitate include massive hemorrhage and uncontrolled bleeding due to hemophilia.
What is the composition of cryoprecipitate?
The composition of cryoprecipitate includes Factor VIII (100IU), fibrinogen (250mg), and variable amounts of von Willebrand factor and Factor XIII.
What are the immediate complications that can occur following colorectal surgery?
The immediate complications that can occur following colorectal surgery include bleeding, infection, and anastomotic leak.
What are the main sites for bleeding following resections of the colon and rectum?
The main sites for bleeding following resections of the colon and rectum are the spleen, which can be injured during the mobilization of the splenic flexure of the colon, and the presacral veins in the pelvis, which can be injured in rectal resections. Other causes of bleeding include slipped ties.
What should be done if bleeding is suspected after colorectal surgery?
If bleeding is suspected after colorectal surgery, the correct course of action is to resuscitate the patient and arrange a return to the operating theatre.
What should be done to prevent wound infections in cases of bowel resection?
In all cases of bowel resection, it is important to administer broad-spectrum intravenous antibiotics before starting the case. Additional doses of antibiotics may be needed intraoperatively for long cases.
Why are wound infections more common following colonic resections, especially in the emergency setting?
due to extensive wound contamination resulting from the underlying disease process.
What is an anastomotic leak?
An anastomotic leak refers to the leakage of fluid or contents from a bowel anastomosis.
How do wound infections postoperatively manifest?
Postoperatively, wound infections may manifest as cellulitis or wound collections. These can usually be managed by draining the collections on the ward and administering antibiotics.
What should be done if an anastomotic leak is suspected?
If an anastomotic leak is suspected (e.g., new atrial fibrillation and raised inflammatory markers 5 days post-resection), the correct course of action is to arrange cross-sectional imaging with a CT scan. If a leak is confirmed and the patient is septic, they should go back to the operating theatre, the anastomosis should be taken down, and the bowel ends should be exteriorized.
What factors contribute to the risk of anastomotic leak?
Anastomotic leaks can occur due to technical failings or patient factors such as background disease. Rectal resections carry the highest risk of anastomotic leak, while left-sided colonic resections carry a higher risk compared to right-sided resections.
