ALS Flashcards
Advanced life support
How long is the CPR cycle, from shock to reassessment of rhythm?
2 minutes
What drugs are used in CPR with shockable rhythm? When are these used?
Adreneline 1mg after the 2nd shock and then every second loop; Amiodarone 300mg after 3 shocks
What drugs are used in CPR with non-shockable rhythm? When are these used?
Adreneline 1mg immediately (as soon as access is obtained), then after every 2nd loop
Name the 4 H’s and 2 T’s to consider and correct during ALS
Hypoxia (oxygen, airway); Hypovolaemia (IVT); Hyper/hypokalaemia or metabolic disorders; hypo/hyperthermia; Tension pneumothorax; tampon add; toxins; thrombosis (pulmonary or coronary)
Name the 5 things you should do in post-resuscitation care following ALS where patient has had ROSC
Reevaluate ABCDE; 12 lead ECG; treat precipitating causes; targeted temperature management; aim for stats 94-98% and normocapnia and normoglycaemia
Name the 4 elements of the Chain of Survival in ALS
- Early recognition and call for help (to prevent cardiac arrest) 2. Early CPR (to buy time) 3. Early defibrillation and ALS (to restart the heart); 4. Post-resuscitation care (to restore quality of life)
Defibrillation should be attempted within ___ minutes of identifying cardio respiratory arrest
3
What proportion of in-hospital cardiac arrests survive and go home?
20%
List the favourable prognostic indicators of survival of in-hospital cardiac arrest
Witnessed, VF, primary MI as the cause, immediate and successful defibrillation
List the 5 links of the Chain of Prevention
Education, monitoring, recognition, call for help and response
List some of the physiological consequences of partial airway obstruction
Cerebral oedema, pulmonay oedema, exhaustion, secondary apnoea, hypoxic brain injury, cardiac arrest. Partial airway obstruction also often precedes complete obstruction
List ath least 6 causes of airway obstruction
CNS depression (loss of airway reflexes and patency), blood, vomitus, foreign body, direct trauma to the face or thorat, epiglottitis, pharyngeal swelling, laryngospasm, bronchospasm, bronchial secretions, blocked tracheostomy or laryngectomy
List some causes of CNS depression that can cause airway obstruction
Head injury, intracerebral disease, hypercapia, metabolic disorders (hypoglycaemia), depressant drugs (alcohol, opioids, GA)
When does laryngospasm occur?
With upper airway stimulation in a semi-conscious patient whose airway reflexes remain intact
What is ‘see-saw’ breathing and what is this a sign of?
Sign of airway obstruction where the accessory muscles of breathing are engaged and the chest is drawn in on inspiratory effort and the abdomen is thrust outwards
What is the treatment for airway obstruction in resuscitation?
Treat any problem that places the airway at risk (suction blood/gastric contents) turn patient on side and given oxygen as soon as possible to maintain sats 94-98%
Describe the the innervation of the main inspiratory muscles, and how a spinal cord lesion might lead to poor respiratory effort or arrest
Intercostal muscles, innervated at the level of their respective ribs, so spinal cord lesions above a particular level may paralyse. The diaphragm is via the 3rd, 4th and 5th segment of the spinal cord. Spontaneous breathing cannot occur with severe spinal cord damage above this level
Describe the effect of a tension pneumothorax on BP
Reduces venous return to the heart and reduces BP
Describe a mnemonic that can be used to assess breathing in the deteriorating patient
RATES - respiratory rate, auscultation, trachea (protrusion vs tug), effort of breathing, saturation
Describe how oxygen should be given to all acutely ill patients who are hypoxic
15L/min via a high concentration reservoir mask (he high volume is to ensure the reservoir bag doesn’t collapse during inspiration). AIm for sats 94-98%
In acutely ill patients, circulation problems are most commonly caused by ______
Hypovolaemia
What is the most common arrest arrythmia associated with ACS?
VF
List at least 5 causes of VF
ACS, hypertensive heart disease, valvular disease, drugs (antiarrthymics, TCAs, digoxin), inherited cardiac diseases like long-QT syndrome, acidosis, abnormal electrolytes, hypothermia and electrocution
List the 4 categories of ACS
STEMI, NSTEACS, NSTEMI, UA
Describe the initial treatment of ACS
Aspirin 300mg crushed or chewed, GTN spray or tablet unless hypotensive, oxygen if hypoxic (sats <94 or hypoxic), pain relief with IV fentanyl or morphine (MONA)
What element of ACS management is different when managing an Indigeous, Maori or Pacific Islander patient?
If giving fibrinolysis, avoid streptokinase due to the high prevalence of anti-streptokinase antibodies in these groups (other drugs would be more effective)
What is the most common cause of sudden cardiac death?
CAD
Why is a history of syncope important in patients with known cardiac disease?
Because syncope is an independent risk factor for increased risk of death
List at least 4 features that indicate a high probability of arrhythmic syncope
Syncope whilst lying down, during or after exercise (though after exercise is commonly vasovagal), with no or brief warning signs, in those with a family history of sudden death or inherited cardiac condition, repeated episodes of unexplained syncope
Name at last 5 signs and symptoms of cardiac disease
Chest pain, SOB, syncope, tachycardia, bradycardia, tachypnoea, hypotention, poor peripheral perfusion, altered mental state, oliguria
Give some examples of asymptomatic or ‘silent’ cardiac disease which can lead to sudden cardiac death
Hypertensive heart disease, aortic valve disease, cardiomyopathy, myocarditis and coronary disease
List at least 3 general signs of respiratory distress
Sweating, central cyanosis, use of accessory muscles, abdominal breathing
What do rattling airway noises in a deteriorating patient suggest?
Airway secretions, usually because the patient cannot cough or take a deep breath
Surgical emphysema in the chest suggests ____ until proven otherwise
Pneumothorax
How should oxygen be administered to patients at risk of T2 respiratory failure if they are hypoxic?
Aim for sats 88-92% with Venuri 28% mask or Venturi 24% mask
What should be done in an emergency situation if a patient has inadequate rate or depth of ventilation?
Use a 2 person bag/mask technique to achieve adequate ventilation whilst calling for help. In a conscious cooperative patient, consider NIV.
In all medial and surgical emergencies, consider ____ to be the likliest cause of shock unless proven otherwise.
Hypovolaemia
In a resusciation setting, what should be given to any patient with cool peripheries and tachycardia? Why?
IV fluids - because hypovolaemia is the most common cause of shock
Explain why BP can be normal in the shocked patient
Because compensatory mechanisms will increase peripheral vascular resistance in answer to reduced cardiac output
In a resusciation setting, a low diastolic BP indicates what?
Arterial vasodilatation (anaphylaxis or sepsis)
In a resusciation setting, a narrowed pulse pressure indicates what?
Arterial vasoconstriction (cardiogenic shock or Hypovolaemia)
Describe what fluid therapy you would give in resuscitation of the deteriorating patient
Rapid bolus 500mL crystalloid (Hartmann’s or NaCl) over less than 15 minutes. Uses smaller volumes (250mL) in patients with heart failure or trauma
What are the 3 D’s that are assessed in the ABCDE algorithm?
Disability - includes drugs, documentation and diabetes
Give an example of how you might treat BGL < 4 in a patient who is unconscious
Give 50mL of 10% glucose IV. Give further doses until the patient fully regains consciousness, or until 250mL of 10% glucose has been given
What is the minimal monitoring that should be attached to the unconscious/deteriorating patient?
ECG, BP and sats
Describe the management of the unconscious patient’s airway if there is a risk of C spine injury
Use jaethrust or chin lift in combination with manual in-line stabilisation of the head anc neck by an assitant. In life-threatening airway onstruction despite the above, add head tilt a small amount at a time until the airway is open
What is agonal breathing and what it this a sign of?
Occasional, irregular gasps - common in the early stages of cardiac arrest. Sometimes present during chest compressions as cerebral perfusion improves, but this is not considered to be ROSC
What is the correct hand position for CPR?
The middle of the lower half of the sternum
Survival rates in CPR are best when the rate is between ___ and ____ per minute
100-120
What is ‘the duty cycle’ of CPR?
Refers to chest compressions and the compression/recoil being of the same duration
Regardless of the method in which ventilating, use an inspiratory time of ___ during resuscitation
1 second
Ventilate the lungs at ___ breaths per minute during resuscitation where intubation has been completed
10 breaths
What equates to ‘1 loop’ on the BLS algorithm?
1 loop is each 2 minute cycle between rhythm checks (the number of 30:2 is less important - use a timer to do a rhythm check every 2 minutes - this is 1 cycle)
What does it indicate when a collapsed patient is found to have a pulse but is not breathing?
Respiratory arrest (diagnosis can only be made if the patient has other signs of life i.e., warm and well perfused, normal CRT)
What are the first steps in resuscitation of a patient who is found to have a pulse but is not breathing?
Ventilate the lungs and check for a pulse every 10 seconds - if there is any doubt about the presence of a pulse, start CPR (all patients in respiratory arrest will develop cardiac arrest)
In what rare circumstance can you deliver ‘stacked shocks’ to a patient in cardiac arrest
If witnessed, if was well oxygenated and perfused immediately prior to the attack (usually in a high dependency unit in hospital), if a manual defibrillator is available and a shock is able to be delivered within 20 seconds, if the initial rhythm is AF/pVT - give 3 successive shocks and assess for ROSC after each shock. If unsuccessful after the third, start CRP. This counts as the first defib attempt in the algorithm
What are the 2 most important interventions that improve survival after cardiac arrest?
Early and uninterrupted chest compressions, and earlu defibrillation for VF/pVT
Describe the appropriate pad placement in ALS
One below the right clavicle, the other in the V6 position in the mid-axillary line
What is the appropriate charge to set on a manual defibrillator in ALS?
200J biphasic for the first shock, which may be increased to 360J for subsequent shocks
Assume that you are doing ALS and, at rhythm check, the pateint displays organised electrical activity compatible with a cardiac output. What is the next step?
Dump the charge and check for ROSC. If present, start post-resus care. If absent, continue CPR and switch to the non-shockable algorithm
Assume that you are doing ALS and, at rhythm check, the pateint displays asystole. What is the next step?
Dumpt he charge, continue CPR and switch to the non-shockable algorithm
The time until ROSC in a successfully defibrillated patient can be as long as _____
2 minutes
Give the 4 reasons why chest compressions should be resumed immediately after delivering a shock in ALS
- Even in successful shocks, it can take up to 2 minutes for ROSC to be detectable 2. Delay in palpating a pulse will further compromise myocardium 3. If a perfuming rhythm has been restored, compressions will not increase the chance of VT recurring 4. In the presence of post-shock asystole, chest compressions may ruefully induce VF
When is amiodarone 300mg given in cardiac arrest?
After 3 shock attempts (any three in an arrest and do not need to be sequential) - can also consider a further 150mg if VT/VF persists afterwards total of 5 shocks
What drug may be used in ALS if amiodarone is not available?
Lignocaine 1mg/kg (but not if amiodarone already given)
What action should be taken in ALS if rhythm cannot be easily distinguished between asystole vs fine VF?
Do not attempt defibrillation, continue compressions and ventilation - as this may improve the amplitude and frequency of VF and therefore the chance of subsequent successful defibrillation
In what situation can precordial thump be considered in cardiac arrest
Rarely - i.e., in a monitored patient in VF/pVT arrest prior to arrival of the defibrillator
Describe the technique for precordial thump
Using the ulnar edge of a tightly clenched fist, deliver sharp impact to the lower haf of the sternum from a height of about 20cm, then retract the fist immediately to create an impulse-like stimulus
How is PEA defined?
Cardiac arrest in the presence of electrical activity (other than VT) that would normally be associated with a palpable pulse (may have some mechanical myocardial contractions but they are too weak to produce a detectable pulse or BP)
Survival following cardiac arrest with asystole or PEA is unlikely unless ?
A reversible cause can be found and treated quickly and effectively
If the diagnosis of asystole is made during cardiac arrest, what other ECG finding should be assessed?
Whether there are p waves - because in these cases, ventricular standstill may be treated with pacing
Physiologically, why is minimisation to pauses in chest compression during CPR so important?
Because even short pauses drastically reduce coronary artery perfusion
What is end-tidal CO2?
The partial pressure of CO2 at the end of an exhaled breath (reflects cardiac output and lung blood flow)
Explain why end tidal CO2 monitoring during CPR is helpful
During CPR, the end ETCO2 is expected to be low, reflecting the low cardiac output state generated by chest compressions. An increase in the monitored CO2 values to normal or near normal may indicate ROSC - waveform capo graphs enables continuous and real time monitoring
List the 5 roles of waveform capnography during CPR
Ensuring correct ETT placement, monitoring ventilation rate and avoiding hyperventilation, monitoring quality of chest compressions (high quality will increase the value), identifying ROSC, prognostication during CPR
If ROSC is suspected during CPR, which drug should be withheld?
Adrenaline
How should drugs which are given peripherally be administered during CPR?
Followed by a 20mL flush (at least) and elevation of the extremity for 10-20 seconds to facilitate drug delivery to the central circulation
What are the 3 sites for IO access in CPR when peripheral access cannot be obtained?
Proximal tibia, distal tibia and proximal humerus
Many hypovolaemic cardiac arrests present with what type of arrythmia?
PEA
Severe hyperkalaemia is K+ above which value?
6.5
What drug is indicated in CPR if the patient is found to be hyperkalaemic?
Calcium
How does calcium work in the treatment of hyperkalaemia?
Directly antagonises myocardial effects of hyperkalaemia by restoring cariomyocyte resting membrane potential, thereby stabilising the cell membrane (i.e., does not decrease serum K+)
If severe acidosis or renal failure is present in a resuscitated patient, which agents should be considered for administration?
Sodium bicarbonate 50mg mmol IV
What is the dose of calcium used in the treatment of hyperkalaemia?
calcium chloride 10% in 10mL
In addition to calcium, which other agents can be used in the management of hyperkalaemia during cardiac arrest?
Shifting agents such as 25g of glucose + units of short acting insulin
Give 2 reasons why calcium carbonate preferred to calcium gluconate in the treatment of hyperkalaemia during cardiac arrest
Firstly, it contains a higher quantity of elemental calciu,, and secondly calcium guconate needs to be hepatically metabolised before the calcium is bioavailable
List at least 3 causes of acute hypocalcaemia which may be seen in cardiac arrest
Shock, sepsis, pancreatitis and drug toxicities
Give an example of why calcium replacement may be beneficial in cardiac arrest
Increased extracellular calcium concentration creates a high calcium gradient which may cause calcium influx and lead to improvement in conduction disturbances and contractility
Hypokalaemia is defines as a serum K+ less than _____?
3.5 (severe < 2.5)
List at least 3 causes of hypokalaemia in the context of cardiac arrest
Usually related to loss or intake including from drugs, gastrointestinal and renal/dialysis or poor intake
Describe how to treat hypokalaemia during cardiac arrest
Administer potassium 5mmol IV as a bolus with consideration of magnesium sulfate 2g IV
Why should you consider giving magnesium sulfate 2g IV with potassium 5mmol for treatment of hypokalaemia in cardiac arrest?
Repletion of magnesium stores will facilitate a more rapid correction of hypokalaemia
How is hypothermia classified?
Body core temperature before 35, and arbitrarily classifed as mild (32-35), moderate (28-32) or severe ( <28)
What is the Swiss staging system?
A way of classifying hypothermia using clinical signs, using 5 stages where 1 relates to mild hypothermia and 5 = death
Describe Stage I of the Swiss staging system
Mild hypothermia (conscious, shivering, core tem 32-35)
Describe Stage II of the Swiss staging system
Moderate hypothermia (impaired consciousness without shivering, core temp 28-32)
Describe Stage III of the Swiss staging system
Severe hypothermia (unconscious, vital signs present, core temp 24-28)
Describe Stage IV of the Swiss staging system
Cardiac arrest or low flow state (no or minimal vital signs, core temp <24)
Describe Stage V of the Swiss staging system
Death due to irreversible hypothermia (core temp 13.7)
Explain how hypothermia affects cardiac function
As core temperature decreases, sinus bradycardia (which is physiological in severe hypothermia) tends to give way to AF, followed by VF and finally asystole
Explain how to manage the hypothermic patient in cardiac arrest with VF, who has not responded to 3 defibrillation attempts
Delay further attempts until core temp 28-30 degrees. CRP and rewarming may need to continue for several hours to facilitate successful defibrillation
Explain why it is reasonable to withhold drugs in CPR for the hypothermic patient, until core temp 28-30
The hypothermic heart may be unresponsive to drugs, attempted pacing and defibrillation. Drug metabolism is slowed, which may lead to toxic plasma concentrations of any drug given
True or false? In the hypothermic patient in cardiac arrest, the interval between any drug doses given should be double that given in a normothermic patient
True - due to delayed metabolism and potential for accumulation
What does ‘after drop’ refer to in regards to the hypothermic patient requiring CPR?
The continued fall in the core temperature after removal from the cold stress due to heat redistribution within the body
Explain why large volumes of IV fluids are needed in the post-resuscitation care of the hypothermic cardiac arrest patient
Warm fluids will cause vasodilatation and expansion of the intravascular space
What temperature is considered diagnostic for hyperthermia?
> 40.6
What is heat exhaustion? What are the symptoms?
A condition of fatigue caused by prolonged exposure to high temperatures, particularly when combined with high humidity and strenuous activity. Symptoms include headache, N+V, malaise. Usually recover rapidly with assistance. Do not usually present with hyperthermia, the body temp is <40
What is heat stroke?
Systemic inflammatory response with a core temp > 40, accompanies by altered mental status or collapse and a varying level of organ dysfunction. Sweating ceases, hot dry skin is present
At what body temperature is sweating maximal?
39 degrees (if fluid not replaced, the sweating will cease and body temperature will rise more quickly)
Explain how exercise in hot environments can result in heat stroke
During exercise, metabolic energy is converted to thermal energy. A large proportion of this energy is liberated as heat. Humans rely on heat loss through evaporation (sweating, breathing). As the environmental temperature rises, the gradient for heat exchange is altered and body temperature rises making it more difficult again to liberate the thermal energy. Sweating will increase, but if fluid not replaced, sweating will cease and the core temperature will rise more quickly.
In which cause of hyperthermic cardiac arrest are pharmacotherapies useful?
Only if caused by malignant hyperthermia (from anaesthetics). In these cases, the offending agent is ceased and dantrolene is given (some evidence that other drugs that cause malignant hyperthermia like MDMA and amphetamines may be treated by dantrolene)
In what arrest setting should one consider immediate administration of a fibrinolytic drug?
If massive PE is suspected as the cause (i.e., one of the 4 T’s)
What is the recommended duration of CPR for a patient who has arrested secondary to a suspected PE and who has been give fibrinolysis?
CPR for at least 30 minutes and up to 90 minutes before terminating
Name the 4 T’s of cardiac arrest
Thrombosis, tension pneumothorax, tamponade and toxins
What is tension pneumothorax? Explain how this condition can lead to cardiac arrest
Progressive build up of air in the pleural space (usually due to a laceration whereby air is allowed into the pleural space but not to return). Progressive build up of pressure pushes the mediastinum toward the opposite hemithorax, and also obstructs venous return to the heart one intra-thoracic pressure exceeds vascular/central venous pressure, thereby leading to circulatory instability and cardiac arrest
Tension pneumothorax in cardiac arrest is a clinical diagnosis. Give some examples of stations where this pathology may be suggested
Thoracic trauma (penetrating or blunt), iatrogenic (thoracic surgery or procedures including central lines, pacemakers, pleural biopsy etc.), asthma, COPD, pulmonary barotrauma
Give some examples of how a patient with a tension pneumothorax might present in the peri-arrest phase
Chest pain, respiratory distress, increasing then decreasing (per-terminal) RR, air hunger, tachycardia, low/falling sats, hypotension and altered consciousness
List at least 3 clinical signs during CPR that may be present in a patient with tension pneumothorax as the cause
Difficulty ventilating due to back pressure, abnormal rise/fall of chest on affected side, decreased breath sounds on affected side, hyper-expanded chest with increased percussion note, tracheal deviation away from the affected side
What is the treatment for tension pneumothorax?
Rapid decompression by thoracostomy or needle thoacocentesis (14G) - when stable, all will have imaging and an established chest drain should be sited, regardless of the technique used
Give at least 5 examples of why needle decompression may fail in the treatment of tension pneumothorax
Obstruction (blood, tissue, kinking cannula), missing a localised tension pneumothorax (cannula too short), inability to drain a large air leak, moving/dislodging
What is the main advantage of needle decompression in the treatment of tension pneumothorax?
Fast (though may recur if not monitored)
What is cardiac tamponade?
Slow or rapid compression of the heart due to the pericardial accumulation of fluid, pus, bloods, clots or gas. Can be the result of effusion, trauma or rupture of the heart, resulting in decreased ventricular filling and subsequent haemodynamic compromise
Explain why cardiac tamponade is difficult to diagnose as a cause of cardiac arrest
Because the typical signs (Beck’s Triad: distended neck veins and hypotension, muffled heart sounds) cannot be assessed during resuscitation/arrest - instead, focussed US should be used
Give at least 5 examples of situations in which cardiac tamponade may be the cause of cardiac arrest
Thoracic trauma, recent thoracic/cardiac surgery, insertion of central access, recent angio or PCI, recent MI, thoracic neoplasm or mediastinal RT, renal failure (uraemia), pericarditis, infectious disease such as TB
List at least 3 clinical signs during CPR that may be present in a patient with cardiac tamponade as the cause
Tachypnoea, dyspnoea, pulsus paradoxus, low voltage QRS or electrical alternans on ECG, Kussmaul’s sign
What is Beck’s triad?
Triad of signs that are diagnostic for cardiac tamponade - distended jugular veins, muffled heart sounds and hypotension
List at least 4 complications of pericardiocentesis
Cardiac dysrhythmia, cardiac puncture, pneumothorax, coronary vessel injury, diaphragmatic injury and death
What is the mainstay of treatment in tricyclic toxicity causing cardiac conduction abnormalties?
Sodium bicarbonate (consider giving during arrest if this is the suspected cause, or in the peri-arrest period if there are still abnormalities on ECGC)
Describe the ways in which amphetamines can cause cardiac arrest
Can cause AMI, necrosis, arrythmias, cardiomyopathy and acute heart failure. They precipitate vascular spasm and therefore cause ischaemic infarction - the myocardial ischaemia causes massive effluent of potassium which can cause arrythmias. The drugs themselves can also induce other reversible causes of cardiac arrest
In what ways can snakes be identified after snake bite?
Residual venom on clothing or skin, or via urine or blood
Describe the process for checking for signs of life during ALS
If signs of life (regular respiratory effort, movement) or readings from monitors are compatible with ROSC (sudden increase in end-tidal CO2 or arterial BP waveform), stop CPR briefly and check the rhythm. If an organised rhythm is present, check for a pulse. If palpable, continue post-resuscitation care. If nil, continue CPR
If CPR does not achieve ROSC and a decision is made to discontinue, for how long should the patient be observed before confirming death?
5 minutes (Andy return of cardiac or respiratory effort during this time should prompt a further 5 minutes observation.
The absence of mechanical cardiac function is normally confirmed using a combination of which signs?
Absence of a central pulse on palpation, absence of heart sounds on auscultation. These can be supplemented by one or more of: asystole on continuous ECG, absence of pulsative flow on arterial monitoring, absence of contractile activity on US
Presume efforts for CPR have been ceased and then patient has been observed for 5 minutes. Which signs must then be checked to confirm death?
Absence of pupillary reflexes, corneal reflexes, motor response to supra-orbital pressure
In an unconscious patient, what is the most common site of airway obstruction?
The pharynx, more often at the epiglottis and soft palate rather than the tongue
List some broad causes of upper airway obstruction in the unconscious patient
Vomit, blood, gastric contents, trauma to the airway, foreign bodies
List some broad causes of laryngeal obstruction
Oedema from burns, inflammation or anaphylaxis, upper airway stimulation (inhaled foreign body) causing laryngospasm
List some broad causes of lower airway obstruction, below the level of the larynx
Excessive bronchial secretions, mucosal oedema, bronchospasm, pulmonary oedema, aspiration of gastric contents
True or false? In the unconscious patient, lower airway obstruction is more common than upper airway obstruction
False.
List at least 2 examples of airway obstruction caused by extrinsic compression
Trauma, haematoma, tumour
Compare the causes of inspiratory stridor vs expiratory wheeze when assessing for airway obstruction
Inspiratory atidor is caused by obstruction at the larynx or above. Expiratory wheeze suggests obstruction of the lower airways, which tend to collapse and obstruct during expiration
What does audible gurgling suggest when assessing a patient for airway obstruction?
Liquid or semisolid material in the upper airways
What does audible snoring suggest when assessing a patient for airway obstruction?
Pharynx partially occluded by the tongue or palate
What does audible crowing or stridor suggest when assessing a patient for airway obstruction?
This is the sound of laryngeal spasm or obstruction
Describe what is meant by see-saw breathing
Represents obstruction of the airway, as the abdomen is pushed inwards during chest attempts to expand during inspiration
After resolution of airway obstruction, supplemental O2 should be titrated to achieve saturations in what range?
94-98% (unless CO2 retainer, in which case aim for 88-92%)
What are the signs of mild airway obstruction in choking?
Attack occurs whilst eating, patient may clutch neck, patient will speak an answer if asked whether choking, will be able to cough/speak/breathe
What are the signs of severe airway obstruction in choking?
Attack occurs whilst eating, patient may clutch neck, won’t be able to answer ‘yes’ when questioned whether choking but may nod instead, patient unable to breathe or sounds wheezy when breathing, attempts at coughing are silent, may become unconscious
What is the management for choking when mild airway obstruction is suspected/present?
If the patient has an effectiver cough, encourge to continue cougihng and observe - continue to monitor for signs of deterioration
What is the management for choking if the patient is conscious but shows signs of severe airway obstruction?
Send for help. Give 5 back blows. If this fails, give up to 5 chest thrusts. If the obstruction has still not resolved, continue alternating 5 back blows with 5 chest thrusts. If the patient becomes unconscious, start CPR. As soon as possible, an expert should undertake laryngoscopy to remove the foreign body
Explain how to give effective back blows when responding to the choking patient with severe airway obstruction
Stand to the side and slightly behind the patient. Support the chest with one hand and lean the patient well forward. Give sharp blows between the scapulae with the heel of the hand - check in between each to see whether the obstruction is relieved
Explain how to give effective chest thrusts when responding to the choking patient with severe airway obstruction
Perform similarly to CPR, with hands in the same position. Give the thrusts more sharply, and at a slower rate
Name the 3 manoeuvres that can be used to relieve upper airway obstruction
Head tilt, chin lift, jaw thrust
Describe how to give head tilt and chin lift to relieve upper airway obstruction
Place one hand on the patient’s forehead and tilt the head back gently - at the same time, place the finger tips of the other hand under the point of the patient’s chin and gently lift to stretch the anterior neck structures
Jaw thrust is most effective when applied with which other manoevre?
Head tilt
Describe how to give jaw thrust to relieve upper airway obstruction
Apply steady upward and forward pressure with the index and other fingers placed behind the angle of the mandible. Use the thumbs to open the mouth slightly by downward displacement of the chin
When upper airway obstruction is caused by relaxation of soft tissues, what techniques will usually clear the obstruction?
Jaw thrust, or head tilt and chin lift
True or false? In a patient with upper airway obstruction, dentures should always be removed if simple airway manoeuvres fail to clear the obstruction
False - well fitting dentures can be left in place, as they help to maintain the contours of the mouth which improves the seal for ventilation via a mask
What should be done next if simple airway manoeuvres fail to relieve an upper airway obstruction?
Look for any foreign body in the mouth and remove with forceps or suction if present. Remove loose dentures or broken teeth and reassess
Describe how upper airway obstruction should be managed in the patient with suspected C spine injury
Use an assistant for manual in-line stabilisation whilst applying chin lift and jaw thrust. If this family to clear the obstruction, gradually apply head tilt until the airway is open. Establishing A and B takes precedent over potential C spine injury (plus the risk is theoretical and relative risk is unproven)
Simply explain how oropharyngeal and nasopharyngeal airways assist in the management of airway obstruction
They overcome soft palate obstruction and backward tongue displacement (though head manoeuvres are still often necessary)
List the common sizes for guedel airways in small, medium and large sized adults
2, 3 and 4-5 respectively
True or false? When using a guedel airway, a size that is slightly too small is more beneficial than one that is slightly too large
False - if in doubt, a larger size is more beneficial
Oropharyngel airways are only intended for use on ____ patients
Unconscious- as may provoke vomiting or laryngospasm in conscious patients (if a patient is intolerant of an oral airway, this is a sign that they do not need one)
Describe how to select an appropriate size guedel airway
Choose an airway which has a length roughly the same as the distance between the patient’s upper incisors and the angle of the mandible
Explain why the oropharyngeal airway should be inserted upside down and then rotated 180 degrees when past the hard palate?
Prevents the tongue from being pushed backwards and downwards
Which size of nasopharyngeal tube is suitable for most adults?
6-7mm
What are some of the risks of nasopharyngeal airways?
Cause bleeding of nasal mucosa in 30% of cases, can cause gagging or vomiting if patient is not deeply unconscious, if tube is too long can cause laryngospasm, caution is needed in patients with suspected base of skull fracture
True or false? When inserting a nasopharyngeal airway, the right nostril should be assessed first and used if patent
.True
Descibe how to correctly handle a nasopharyngeal airway during insertion
Hold the upper third of the device - that way, if the tip meets an obstruction, the airway should hopefully bend before causing trauma. Use a slight twisting motion whilst advancing a lubricated tube along the floor of the nasal cavity. Never continue if resistance is met.
A standard oxygen mask (i.e., Hudson) can provide what percentage of inspired oxygen?
50% (providing flow is high enough)
During resuscitation, what oxygen concentration should initially be given, and how is this achieved?
Highest concentration possible - a mask with a reservoir (non re-breather) can deliver an inspired oxygen concentration of 85% at flow rates of 10-15L/min
Although wide-bore rigid suckers (Yankauer) are recommended for removing liquid from the upper airway in resuscitation, when are fine-bore flexible suckers useful?
Can be used in patients with minimal mouth opening, and can be passed through a nasopharyngeal or oropharyngeal tube
When performing mouth-to-mouth or mouth-to-mask ventilation, what is the expired oxygen concentration provided by the rescuer?
16%
The risk of gastric inflation and subsequent regurgitation with mouth-to-mask ventilation are increased by what factors?
Blowing too hard and generating tidal volumes that are too large, incompetent oesophageal sphincter of all patients in cardiac arrest
What are the recommendations for giving safe and effective rescue breaths in mouth-to-mouth or mouth-to-mask ventilation in CPR?
2 breaths:30 compressions. Each breath should be given over 1 second, at a volume which corresponds to visible chest movement (balances the risks and benefits of giving enough volume, reducing the risk of gastric inflation and allowing enough time for chest compressions)
If oxygen is available for use with mouth-to-mask ventilation, how should this be incorporated?
Via the mask port at a flow rate of 10L/min
Describe the mechanics of ventilation with a self-inflating bag attached to either a mask, LMA or ETT
The self-inflating bag is squeezed and the contents are delivered to the patient’s lungs. On release, the expired gas is diverted to the atmosphere via a one-way valve. The bag then regfills automatically via an inset at the opposite end.
Describe the inspired oxygen concentration that can be achieved when using a self-inflating bag attached to either a mask, LMA or ETT
Without supplemental oxygen, ambient air only is ventilating the lungs (21%). This is increased to about 45% by attaching high-flow oxygen directly to the bag adjacent to the air intake. An inspired oxygen concentration of 85% can be achieved if a reservoir system is attached and the oxygen flow rate is high (10-15L/min)
Name the 2 techniques recommended for holding the mask onto the face in bag-mask ventilation
C-E and thenar eminence grip methods
Describe the C-E technique for holding the mask in bag-mask ventilation
The thumb and index finger holding the mask and the inferior and superior mask borders (the C). The other 3 fingers hold the mandible while pulling the face into the mask (the E)
Describe the thenar eminence technique for holding the mask in bag-mask ventilation
Pressure is applied to the mask by placing both thenar eminences parallel to the long axis of the mask. The other 4 fingers are placed under the mandible to apply jaw lift
What is the main advantage of the LMA supreme in CPR as the supraglottic airway of choice?
It is single use, forms an improved seal for airway protection and has a gastric drainage port
LMAs should try to be inserted without breaks to CPR. However, if compressions must cease, limit the pause to less than __ seconds
5
What sizes of LMA are appropriate for most men and women?
5 for men; 4 for women
How much air is used to inflate the cuff of an LMA?
40mL for a size 5 (men) and 30mL for a size 4 (women)
Describe the next steps if an LMA has not been able to be placed in 30 seconds
Reoxygenate the patient with a pocket mask or bag mask before reattempting LMA insertion
Explain why the iGel airway is ideal for resuscitation
It has been used widely so there is lots of data; does not have a cuff that needs to be inflated; incorporates a bite block and gas tribe tube port; easy to insert without stopping CPR; forms good laryngeal seal and is very easy to use
Which size of iGel is recommended for most adults in CPR?
A size 4 will function well in most adults, though small females may require a 3 and tall men a 5
Describe the position of the leads in a 3 lead ECG
White is right - right shoulder. Black to the left shoulder. Red to the left leg.
Describe why it is important to position ECG electrodes over bone rather than muscle?
Because it reduces electrical interference - particularly from patient motion or CPR (prevents the baseline from varying and making interpretation difficult)
If ECG is not immediately available, describe how cardaic rhythm can quickly be assessed in the collapsed patient
As soon as possible, obtain a rhythm by applying defibrillator pads - this can be done to make a quick assessment whilst waiting for a formal 12 lead ECG
Explain why cardiac monitors are not appropriate for the analysis of detailed cardiac rhythm (and are for recognition of rhythm only)
Because the electrical frequency of monitors if much smaller
What does the P wave of an ECG represent?
The electrical impulse emanated from the SA node to the atrial muscle (i.e., the depiction is that of electrical depolarisation
The AV node and His-Purkinje system enable what function of the heart muscle?
Synchronised/coordinatred ventricular depolarisation
What is reflected in the QRS complex of an ECG?
Ventricular depolarisation
What is reflected by the T wave of an ECG?
Ventricular repolarisation
With normal depolarisation, the duration of the QRS complex of an ECG will be less than ___
0.12 seconds/3 small squares (i.e., narrow)
If one of the bundle branches of the heart is diseased, what effect will this have on the QRS complex of an ECG?
It will be widened (greater than 0.12 seconds/3 small squares)
List the 6 steps for analysing rhythm on an ECG in an emergency
- Is there any electrical activity? 2. What is the rate? 3. Is the rhythm regular? 4. Is the QRS complex widened? 5. Is there any atrial activity? 6. Is the atrial activity related to the ventricular activity, and how?
What is the first step in management if you see no electrical activity on ECG?
Check the patient - if no normal breathing, start CPR. Then check that the gain control is not too low and that the leads are connected to both the patient and monitor
Describe the appearance of asystole on ECG
Flat line with no deflections, it usually some undulation of the baseline or interference due to respiratory movement or CPR. A completely flat line usually means that a lead has become disconnected. Atrial activity (P waves, AF or flutter) may persist for a short time after the onset of asystole
Explain why it is important to be able to recognise ventricular stand still on an ECG, where there may still be some atrial activity
Because external pacing of this rhythm is more likely to produce some cardiac output than in other cases of complete asystole
Which rhythm strip is used to diagnose asystole?
Strip 5
Which rhythm strip is used to diagnose ventricular standstill?
Strip 6
Which rhythm strips are used to diagnose coarse vs fine VF?
Strip 2 for coarse and Strip 3 for fine
VF can be classified into coarse or fine based on which ECG appearance?
Amplitude of QRS complexes
What should be the course of action if there is any doubt on ECG about whether the rhythm is asystole vs fine VF?
Do not attempt defibrillation, instead continue CPR and ventilation - this is because high quality CPR may improve he amplitude and frequency of the VF and improve the change of subsequent successful defibrillation to a perfuming rhythm
Bold lines on ECG paper represent ___mm
5mm
What is the standard paper speed of an ECG?
25mm/s
1 second is represented by ___ large squares and ___ small squares on ECG paper
5; 25
To estimate HR on ECG, count the number of R waves what occur in __seconds/___ large squares, and multiply it by 10
6; 30
If the QRS complex of an ectopic beat on ECG is narrow, the beat is likely to have come from what part of the heart?
Above the ventricular myocardium (i.e., the atrial muscle or AV node)
Explain why some ventricular ectopic beats can be accompanied by a P wave occuring shortly after the QRS complex
Due to retrodgrade conduction from the ventricles or atria
Ectopic bets that occur early (before the next regular sinus beat was due to occur) are termed _____ beats
Premature
What is an escape beat on ECG?
A beat that arises from the AV node or ventricular myocardium after a long pause (i.e., in sinus bradycardia).
What does an escape beat on ECG imply?
The the focus in the AV node or ventricle that generates the beat is acting as a back-up pacemaker because the normal pacemaker function of the SA node is too slow or absent
What is complete AV block?
A type of escape rhythm where the cells generating the ventricular rhythm as acting as a pacemaker because no atrial impulses are transmitted to the ventricles
If more than 3 ectopic beats occur in rapid succession, this is termed _____
Tachyarrythmia
An arrhythmia that occurs intermittently, interspersed with periods of normal sinus rhythm, is described as _____
Paroxysmal
When ectopic beats occur alternately with sinus beats for a sustained period, this is called _____
Bigeminy
Describe what is indicated by a narrow QRS on ECG
Duration <0.12 seconds, indicates that the rhythm originates above the bifurcation of the bundle of His (SA node, atria, AV node - i.e., supracentricular structures)
If the QRS complex is greater than 0.12 seconds, the rhythm may be coming from which structures?
From ventricular myocardium, or could also be supraventricular rhythm that is tramsmitted with aberrant conduction (i.e., bundle branch block)
On ECG, sinus P waves are upright in which leads?
II and aVF (and will be dome-shaped)
Explain what is indicated when P waves on an ECG are inverted in leads II and aVF
This occurs when there is retrograde activation of the atria from the region of the AV node (i.e., junctional rhythm or ventricular in origin) - because atrial depolarisation travels in the opposite direction to normal
Lead V1 is often useful to clear demonstration of which P wave morphologies?
Sinus P waves and AF
Describe the ECG appearance of atrial flutter, and which leads this rhythm is best seen in
Triangular flutter waves, regular saw-tooth appearance and occurring at rates of 300/min. Best seen in inferior leads II, III and aVF
In a sustained tachycardia, it may be difficult to tell whether there is any atrial activity between the QRS complexes. Give an example of a treatment which may reveal atrial activity in these situations
If a regular tachycardia of 150bpm is caused by flutter, it may be hard to see the flutter waves. Transiently causing an AV block may help to reveal flutter waves - this can be achieved by vagal stimulation or an IV bolus of adenosine
If there is a consistent interval between each P wave and QRS complex on ECG, what does this suggest?
That conduction from the atrial to the ventricles is intact
Give 2 examples of atrioventricular dissociation (where there is no relationship between P waves and QRS complexes on ECG
- Complete 3rd degree heart block (activity in the atria is accompanied by a regular bradycardia arising below the AV node); 2. Some types of VT in which regular broad complex QRS complexes are present and regular P waves are seen out of phase with the QRS complexes
How do the QRS complexes differ in complete AV block vs second degree blocks such as Mobitz or Wenckebach
In AV block, the QRS is usually regular. In segond degree, it is often irregular (and there will be a recurring pattern)
If AF is accompanied by a completely regular ventricular rhythm with a slow rate - what is the likely explanation?
AF in the presence of AV block
Describe the appearance of VF on ECG
The ventricular myocardium depolarises randomly, so the ECG will show rapid, bizarre, irregular waves of widely varying frequency and amplitude
Describe the appearance of VT on ECG
Broad-complex tachycardia (in monomorphic VT, the rhythm is usually regular at rates of 100-300bpm)
What is the definition of PEA?
Normal (or near normal) electrical activity without effective cardiac output
Give some simple examples of what treatments might be required for a patient with bradycardia with adverse features (low BP, fainting, chest pain, heart failure)
Atropine (to prevent imminent cardiac arrest) or pacing
List some adverse features of bradycardia which may need urgent treatment to prevent cardiac arrest
Fainting, chest pain, hypotension, heart failure
What is meant by ‘agonal rhythm’ on ECG?
Characterised by slow, irregular, wide ventricular complexes of varying shape, and does not generate a pulse. It is usually seen during the late stages of unsuccessful resuscitation - the complexes will continue to become broader until all recognisable electrical activity is lost
Following onset of VF/pVT, cardiac output ceases and cerebral hypoxia injury commenced within ___ minutes
3
Without CPR, for every 1 minute between collapse and defibrillation, mortality increases by what degree?
7-10%
At what point in the algorithm do the 2 minute loops of ALS begin?
As soon as defibrillation arrives, the pads are connected, the rhythm is examined and a shock is delivered if indicated - then the 2 minutes begin
What is the definition of defibrillation?
The passage of electrical current across the myocardium to depolarise a critical mass of heart muscle simultaneously, enabling the natural pacemaker tissue to resume control
Defibrillators contain which 3 components?
- Power source capable of providing direct current, 2. Capacitor that can be charged to a pre-determined energy level, 3. Two electrodes across which the capacitor is discharged
What is the definition of successful defibrillation?
Defined as the absence of VF/pVT at 5 seconds after shock delivery (although the ultimate goal is ROSC)
List the 4 factors which affect defibrillation success
- Transthoracic impedence, 2. Electrode position, 3. Shock energy, 4. Shock sequence
What is impedence compensation in defibrillation?
A function of some defibrillators, in which they compensate automatically for transthoracic impedence if detected
Which electrode position is preferred for transcutaneous pacing?
Anterior electrode pad over the left -recording, one on the back behind the heart, just inferior to the left scapula
Aside from the normal position, list the names for the other 3 acceptable electrode/pad positions in defibrillation
Antero-posterior, bi-axillary, postero-lateral
If using a manual defibrillator, the initial shock energy should be set to _____
200J
Describe how shock energy should be adjusted during ALS
First shock 200J. If unsuccessful, second and subsequent shocks can be delivered using either fixed or increasing energies. If a shockable rhythm recurs after successful defibrillation, given the next shock at a higher energy
Every 5 second increase in the pre-shock pause (time between stopping compressions and delivering the shock), decreases the chance of successful defibrillation by_____
Half
If electrical cardioversion is used to convert atrial or ventricular tachyarrythmias, the shock must be synchronised with the ___ wave on ECG
R
Explain why electrical cardioversion must be synchornised with the R wave (not the T wave) on ECG
By avoiding the refractory period, it minimises the risk of inducing VF
What are the ultimate goals of ALS?
To achieve ROSC and return the patient to a state of normal cerebral function, and to establish and maintain a stable cardiac rhythm and haemodynamic stability
The post-cardiac arrest syndrome incorporates which 4 factors?
Post-cardiac arrest brain injury, post-cardiac arrest myocardial dysfunction, systemic ischaemia/reperfusion response, persistent precipitating pathology
What are the aims of airway and breathing post resuscitation care?
Achieve sats 94-98% and ventilate to achieve normocapnia. Advanced airway should be placed if not already
What are the elements of ‘circulation’ in the post resuscitation care algorithm?
Obtain ECG, reliable IV access, SBP >100, restore normovolaemia with fluids, arterial line for BP monitoring, consider vasopressin if needed
What is recommended for post-resuscitation care in regards to temperature?
Maintain constant temperature 32-36 for >24 hours, prevent fever for at least 72 hours
How does post-cardiac arrest brain injury manifest?
Coma, seizures, myoclonus and varying degrees of neurological dysfunction and brain death
What is the prognosis for myocardial dysfunction in post-cardiac arrest syndrome?
Common after cardiac arrest but typically recovers after 2-3 days
What is the mechanism for multiple organ failure and increased risk of infection after cardiac arrest?
the systemic ischaemia/reperfusion response in post-cardiac arrest syndrome incites immunological and coagulation pathways which causes the same
The post-cardiac arrest syndrome has many features in common with which other pathology, casing intravascular volume depletion and vasodilatation?
Sepsis
In the immediate post-resuscitation phase, treat the patient by following the ____ approach
DRABCD
If an intubated patient regains consciousness soon after ROSC, is cooperative and breathing normally, why should exhumation be considered early?
Because coughing on the tube may provoke arrythemias and/or hypertension. If immediate extubation isn’t possible, sedate the patient
What should be assessed in the ‘Breathing’ assessment of a patient post-resuscitation?
Ensure equal breath sounds, ensure tubes that have been places are in the right location, if ribs have been fractured during CPR there may be a flail segment/pneumothorax, listen for evidence of pulmonary oedema or aspiration of gastric contents (consider placing a gastric tube)
What may be suggested by grossly distended neck veins when inclined in a patient post-resuscitation?
Right heart failure or cardiac tamponade
What signs may indicate left ventricular failure in the post-resuscitated patient
Pink frothy sputum or fine inspiratory crackles on auscultation
What treatment is indicated in a patient in the post-resuscitation period who has evidence of ST elevation or new LBBB on ECG?
PCI to reopen the occluded coronary artery
In what timeframe should PCI be perused in patients with evidence of MI post-resuscitation?
120 minutes (and fibrinolysis should be given if this timeframe can’t be achieved)
List the 6 investigations that are recommended for any patient in the post-resuscitation period
FBC; biochemistry (including troponin for serial monitoring); ECG; CXR; ABG; echo
Which 4 things should accompany the post-resuscitation patient on transfer to high acuity care?
Portable suction, oxygen supply, defibrillator, monitor
How does post-resuscitation myocardial dysfunction manifest?
Haemodynamic instability, hypotension, low cardiac output and arrhythmias
In the absence of definitive data supporting a specific goal for BP following arrest, target the mean arterial BP to what?
To achieve an adequate urine output (1mg/kg/hr)
Immediately after ROSC, there is a period of cerebral ____, followed by ___ _____ ____
Hyperaemia, low blood flow
After ROSC, normal cerebral auto regulation is lost, leaving cerebral perfusion dependent on what?
Mean arterial pressure
Following ROSC, what is the target for BGL?
<10, and must not go below 4
List the 4 advantages of using targeted temperature control of 36 degrees after ROSC
Reduced need for vasopressor support, lactate values are lower, rewarming phase is shorter, reduced risk of rebound hyperthermia after rewarming
The practical application of targeted temperature control is divided into which 3 phases?
Induction, maintenane and rewarming
List at least 5 examples of cooling techniques in targeted temperature management after ROSC
Cold IV fluids, simple ice packs and wet towels, cooling blankets, water or air circulating blankets, transnasal evaporative cooling, intravascular heat exchanges (femoral or subclavian veins), extracorporeal circulation (ECMO)
What is the recommended rate of rewarming after ROSC?
0.25-0.5 degrees of warming per hour
In most cases, prognostication is not reliable until after ___ hours from cardiac arrest
72
Describe how an O2 saturation monitor works
Oximeter probe containes an LED and a photoreceptor opposite. This is placed across tissue, and some of the LED light is transmitted through the tissue and some is absorbed. The ratio of the trasmitted to absorbed light is used to general a peripheral arterial oxygen saturation
The displayes sats alters every ___ seconds, giving the average SpO2 over the preceding ___ seconds
0.5-1 seconds; 5-10 seconds
What information is NOT given by pulse oximetry
Tissue oxygenation (measures saturation only, not content); no indication of adequate ventilation as does not measure CO2
The relationship between oxygen saturation and arterial oxygen partial pressure (PaO2) is demonstrated by what?
The oxyhaemoglobin dissociation curve
Describe what is meant by the sinusoidal nature of the oxyhaemoglobin dissociation curve
An initial decrease from a normal PaO2 is not accompanies by a decrease of similar magnitude in the oxygen saturation of the blood. This means that early hypoxaemia may be masked. At the point where SpO2 reaches 90-92%, the PaO2 will have decreased from between 90-104 to 60mmHg. In other words, the arterial blood will have lost more than 25% of it’s oxygen content for a fall of only 6-8% in SpO2
Explain why saturations below 70% on pulse oximetry are highly unreliable
Because the output from oximeters relies on a comparison between current signal output and standardised reference data from healthy volunterrs
Give at least 6 reasons why pulse oximetry may be inaccurate
Presence of other harmoglobins (carboxyhaemoglobin from carbon monoxide poisoning, methaemoglobin which can be congenital or acquired, faetal haemoglobins and sickling red cells), surgical and imaging dyes like methylene blue, nail varnish, false nails, hih-ambient light levels (fluouroescent), motion artefact, reduced pulse volume (Hypothesion, low CO, vasoconstriction, hypothermia)
True or false? Anaemia (reduced Hb), jaundice (hyperbilirubinaemia) and skin colour can affect pulse oximetry?
.False
What are the 4 main uses of pulse oximetry?
- Detection of hypoxaemia 2. Targeting oxygen therapy 3. routine monitoring 4. Diagnostic (sleep apnoea)
Where possible in the resuscitation setting, give oxygen via a _____ mask, at a rate of ____
Non-rebreather; 15L/min
What O2 therapy is recommended to critially ill patients or those in per-arrest situations when they are already receiving nebulisers
Place a second O2 tubing set/nasal prongs underneath the mask at a flow rate of 15L/min
List at least 5 causes of type I respiratory failure
COPD; PE; pulmonary oedema; pulmonary fibrosis; pulmonary hypertension; lung infection/inflammation (pneumonia, arterio-venous right to left shunt as in congential heart disease)
List at least 5 causes of type II respiratory failure
COPD; acute severe asthma; CNS depression from opioids or sedatives or head injury or neuromuscular disease; chest wall abnormalities/trauma
What parameter is used to define the concentration of oxygen in arterial blood?
PaO2
What is PaCO2?
The concentration of carbon dioxide in arterial blood
Use inspired O2 concentration of ___% until ROSC
100 (after which, aim for sats 94-98, or 88-92)
Which principle allows an informed person to make a decision about their healthcare, even it tht choice is considered illogical or incorrect by others, including health professionals?
Autonomy
Which principle involves provision or benefit to an individual while balancing benefit and risk?
Beneficience
List the 4 key principles of medical ethics
Autonomy, beneficence, non-malevolence, justice
Give an example of a situation in which CPR should not be offered nor attempted
If the healthcare team is certain that a patient is dying as an inevitable result of underlying diease or a catastrophic health event, and that CPR would not re-start the heart and breathing for a sustained periods
When is it generally accepted that CPR should be continued?
When there is a shockable rhythm persisting or reversible causes are present
It is accepted that asystole for more than __ minutes, in the absence of a reversible cause is unlikely to be successful
20
Achieving ROSC does not mean that CPR has been successful - a resus attempt can only be regarded as successful in what condition?
If it restores a patient to a duration and QOL that they, themselves, regard as worth having
State the dose of adreneline/epinephrine used in cardiac arrest
1mg (10mL 1:10,000 or 1mL of 1:1000)
When should IV adrenaline be given in PEA/asystolic cardiac arrest?
As soon as IV access has been obtained
Name the symphathomimetic drug given in cardiac arrest. What is it’s mechanism of action?
Adreneline/epinephrine. Alpha-adrenergic effects causing systemic vasoconstriction, which increases coronary and cerebral perfusion pressures. The beta-adrenergic effects are ionotropic and chronotropic which may also increase coronary and cerebral blood flow.
List the adverse effects of adreneline when used in cardiac arrest, which may offset it’s benefits
Whilst it may increase coronary and cerebral perfusion, it also increases myocardial oxygen consumption and ectopic ventricular arrythmias (particularly in the presence of acidaemia), transient hypo anemia because of pulmonary arterial venous shunting, impaired microcirculation and increase post cardiac arrest myocardial dysfunction
How can amiodarone be administered in cardiac arrest?
300mg as an IV bolus (ideally diluted in 5% dextrose to a volume of 20mL), should be flushed with 0.9% normal saline or 5% dextrose
At what point in ALS is amiodarone given?
300mg after 3 defibrillation attempts, and then a further 150mg if shockable rhythm persists after 5 defibrillation attempts (NB there is no role for amiodarone in non-shockable rhythms)
What is the mechanism of action of amiodarone?
It is a membrane-stabilising anti arrhythmic drug that increases the duration of the action potential and refractory period in atrial and ventricular myocardium. AV conduction is slowed, and a similar effect is seen in accessory pathways. It has a mild negative ionotropic effect and causes peripheral vasodilatation through non-competitive alpha blocking effects.
What other medication may be considered in cardiac arrest with a shockable rhythm, if amiodarone is unavailable?
IV Lignocaine (initial dose 100mg, repeated bolus of 50mg if necessary)
Explain why 5% dextrose is inappropriate for resuscitation in cardiac arrest
Because it is rapidly redistributed away from the intravascular space and causes hyperglycaemia which may worsen neurological outcome and survival after cardiac arrest
In what situations is IV calcium indicated in cardiac arrest? What is the dose?
For PEA caused specifically by hyperkalaemia, hypocalcaemia or calcium-channel-blocker overdose. Give 10mL 10% calcium chloride
Calcium carbonate and ____ ____ should not be given simultaneously by the same route
Sodium bicarbonate
What are the adverse effects of IV calcium in cardiac arrest?
High plasma concentrations after injection may be harmful to the ischaemic myocardium and may impair cerebral recovery
In what situations is IV sodium bicarbonate indicated in cardiac arrest? What is the dose?
In shockable and non-shockable rhythms when cardiac arrest is associated with hyperkalaemia or if there was known TCA overdose. Give 50mmol (50mL of an 8.4% solution). The dose can be repeated, but acid base monitoring should guide this
What is the best treatment for acidosis in cardiac arrest?
Chest compression
Bicarbonate causes generation of ____ ____, which diffuses rapidly into cells
Carbon dioxide
What are the 4 major adverse effects of giving sodium bicarbonate in cardiac arrest?
Sodium bicarbonate causes generation of CO2, which diffuses rapidly into cells. This has the following effects: 1. Exacerbates intracellular acidosis 2. Produces a negative ionotropic effect on ischaemic myocardium 3. Presents a large, osmotically-active sodium load to an already compromised circulation and brain 4. Produces a shift to the left in the oxygen dissociation curve, further inhibiting the release of oxygen into the tissues
The use of which drugs are well accepted in cardiac arrest that is likely to have been caused by a PE? State the drug names and doses.
Tenectaplase 500-600mcg/kg as an IV bolus; Alteplase (rtPA) 10mg IV bolus - after which further doses can be given to a total of 50mg at 15 mins and 100mg by 2 hours
Suppose a fibrinolytic drug is given in cardiac arrest presumed to be caused by a PE. For how long is it appropriate to continue CPR in these cases?
For at least 60-90 minutes
State the dose of adreneline used in anaphylaxis
0.5mg (0.5mL of 1:1000) IM route
For persistent upper airway obstruction in anaphylaxis, give _____ _____, for persistent lower airway obstruction give _____ _______
Nebulised adreneline; nebulised salbutamol
What is anaphylaxis?
Severe, life-threatening generalised or systemic hypersensitivity reaction, characterised by rapidly developing life-threatening airway and/or breathing and/or circulation problems usually associated with skin and mucosal changes
What is the ASCIA definition of anaphylaxis?
Any acute onset illness with typical skin features (urticaria rash or erythema/flushing and/or angiooedema), PLUS involvement of respiratory and/or cardiovascular and/or persistent severe gastrointestinal symptoms OR any acute onset of hypotension or bronchospasm or upper airway obstruction where anaphylaxis is considered possible, even if typical skin features are not present
Anaphylaxis and risk of death is increased in those with pre-existing ____, especially if it is poorly controlled
Asthma
List at least 5 factors which are associated with increased risk of fatal anaphylaxis
Delayed/no administration of adrenaline; upright posture during reaction; pre-existing asthma; food allergic individuals eating away from home; initial misdiagnosis
In terms of risk of death from anaphylaxis - which population groups are more at risk from stings vs drug allergy vs food allergies
Teenagers and young adults from food allergies, older adults for stings and drug allergies
Most fatal insect sting anaphylactic reactions occur in which population?
Older people with heart disease
Most deaths from food induced anaphylaxis occur from which 3 food groups?
Peanuts, tree nuts and shellfish
Anaphylaxis is likely when all three of whcih factors are present?
- Sudden onset and rapid progression of symptoms 2. Life-threatening airway and/or breathing and/or circulation problems 3. Skin and/or mucosal changes (flushing, urticaria, angioedema)
Give some examples of Airway problems in evolving anaphylaxis
Throat and tongue swelling, airway oedema, patient has difficulty breathing and feels the throat is closing up, difficulty swallowing, hoarse voice, staid or (high pitched inspiratory noise caused by upper airway obstruction)
Give some examples of Breathing problems in evolving anaphylaxis
SOB, tachypnoea, wheeze, tiredness, confusion (hypoxia), cyanosis (late sign), respiratory arrest
Give some examples of Circulation problems in evolving anaphylaxis
Signs of shock (pale, clammy), tachycardia, hypotension (feeling faint, collapse), decreased consciousness, MI and ECG changes, cardiac arrest
Name the minimum monitoring required in anaphylaxis
Pulse oximetry, NIBP and 3-lead ECG
How should oxygen be given in anaphylaxis?
Initially give the highest concentration possible using a mask with an oxygen reservoir. Once sats can be obtained, target 94-98%
Explain the mechanism of action of adreneline in anaphylaxis
Alpha-receptor agonist activity reverses peripheral dilatation and reduces oedema. The beta-receptor activity dilates the bronchial airways, increases the force of myocardial contraction and suppresses histamine and leukotriene release
After the initial dose of adrenaline in anaphylaxis, further doses can be given every __ minutes
5
What is the next treatment to administer after adrenaline in anaphylaxis?
IV fluid challenge - give 500-1000mL and monitor the response, giving more as needed.
True or false? Antihistamines have no role in treating or preventing respiratory or cardiovascular symptoms in anaphylaxis
.True
True or false? IV or IM hydrocortisone 100-200mg may help to prevent or shorten protracted reactions in anaphylaxis
.True
What are the warning signs of progressive airway obstruction in anaphylaxis?
Angiooedema - swelling of the eyes, lips or tongue, hoarseness of the voice and oropharyngeal swelling
What is the clinical definition of septic shock?
Sepsis with a serum lactate >4 or hypotension unresponsive to fluid resuscitation
Urgent assistance should be sought for any septic patient with any of which 4 factors after appropriate fluid resuscitation?
Hypotension, oliguria, acute confusion, lactate > 4
What are the 3 standard physiological parameters that are sought after in the post-resuscitation care of a septic patient
MAP >65, normal CVP and urine output
List the steps in the Sepsis Six
- High flow O2 2. Blood cultures 3. Broad spectrum ABX 4. Fluid resusitation 5. Measure lactate 6. Measure urine output
What is the rationale for giving high flow oxygen in septic patients (Step 1)?
Hypotension, disordered capillary beds and microthrombi will be compromising oxygen delivery to the tissues.
What is involved in Step 2 of the Sepsis 6?
Take at least 1 set of blood cultures and samples of any other fluid which may be related to the presumed source before starting antibiotics. If the presumed source is amenable to control (i.e., a line removed or abscess drained) complete this as soon as possible (and always within 12 hours)
What is involved in Step 3 of the Sepsis 6?
Give broad spectrum antibiotics as soon as possible whilst initiating fluid resuscitation (step 4), always within the first hour. Delays in antibiotics are directly liked to poor outcomes.
What is the most common form of organ dysfunction in septic shock?
Circulatory shock, resulting from a combination vasodilatation and Hypovolaemia (due to leaky capillaries)
What is involved in Step 4 of the Sepsis 6?
Initiate fluid resuscitation. Give fluid challenges in divided blouses of 250-500mL of crystal load to a max volume of 30mL/kg in patients with hypotension, lactate >2 or other signs of circulatory dysfunction such as low urine output
What does elevated lactate signify in sepsis?
By-product of anaerobic metabolism, indicates circulatory compromise and is a predictor of outcome
