Regarding cardiac arrest secondary to hypothermia, which ONE of the following statements is TRUE?
Answer: B: The temperature at which defibrillation should first be attempted and how often it should be tried in the severely hypothermic patient has not been established. The current recommendation is that rescuers should attempt defibrillation (up to 3 shocks) without regard for core temperature. It may be impossible to achieve conversion to normal rhythm if <30°C; however, it seems unacceptable to delay defibrillation attempts to assess core temperature. Further care, after initial shocks, is determined by core temperature. If the core temperature is <30°C, withhold defibrillation until it becomes >30°C because the fibrillating myocardium is unlikely to respond at that temperature.
There are concerns that intubation may precipitate VF. Current opinion is that endotracheal intubation is safe in severe hypothermia and early intubation provides effective ventilation with warm, humidified oxygen and isolates the airway to reduce the likelihood of aspiration. The optimum rewarming technique is still controversial but warming gas and fluids to 40°C is a simple, safe and effective method.
Drug metabolism is markedly reduced at low temperatures and medications may accumulate to toxic levels if given repeatedly. It is recommended to withhold IV medications if the core temperature is <30°C. Once 30°C has been reached, the intervals between drug doses should be doubled when compared with normothermia intervals. As normothermia is approached (>35°C), standard drug protocols should be used.
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Which ONE of the following statements is TRUE regarding post cardiac arrest care in adults?
Answer: D: Immediate emergent angiography and PCI is recommended in all patients with ST elevation or new LBBB on ECG following ROSC after an OHCA. It is also recommended in selected patients without ECG changes or prior clinical findings such as chest pain. Coma is a common finding in patients with an OHCA and is not a contraindication to angiography.
Systolic BP should be maintained >100 mmHg and oxygen titrated to achieve a saturation of 94–98%. Hyperoxaemia may lead to potential harm in patients after ROSC. Insulin infusion should be commenced if the blood sugar level is >10 mmol/L but hypoglycaemia should be avoided.
Which ONE of the following statements is TRUE regarding therapeutic hypothermia in patients with return of spontaneous circulation after a cardiac arrest?
Answer: B Several studies have demonstrated improved neurological outcome in comatose patients after out-of-hospital VF cardiac arrest. Recent studies suggest that induced hypothermia might also benefit comatose adult patients with ROSC after an OHCA from a non-shockable rhythm, or after an in-hospital cardiac arrest. The ILCOR 2010 guideline therefore recommends that comatose adults with ROSC after out-of-hospital VF cardiac arrest should be cooled to 32–34 °C for 12–24 hours and that therapeutic hypothermia should be considered in comatose survivors of an OHCA after all rhythms or after an in-hospital cardiac arrest. This can be safely initiated with a rapid infusion of 4°C normal saline at 30 mL/kg over 2 hours.
Regarding prognostication after resuscitation in adults, which ONE of the following reliably predicts poor outcome?
Answer: B Regarding prognostication after cardiac arrest: • In adult patients comatose after cardiac arrest who had not been treated with therapeutic hypothermia:
In adult patients comatose after cardiac arrest who had been treated with therapeutic hypothermia:
Regarding emergency transcutaneous pacing (TCP), which ONE of the following statements is TRUE?
Answer: A: Emergency transcutaneous pacing (TCP) is indicated in patients with haemodynamic significant bradycardia that is unresponsive to atropine or other chronotropic drugs. Previously, TCP was recommended in asystolic cardiac arrest, but the 2010 ILCOR and ARC guidelines do not support its routine use anymore.
Pacing is usually initiated at a rate of 70–80 bpm. The pacing current should be set by starting at the minimum setting and slowly increasing the output until a pacing spike appears on the monitor. Continue increasing the output until electrical pacing capture is achieved. Pacing capture is present when each pacing spike is followed by a ventricular depolarization with visible QRS complex and repolarization with a T wave. Each pacer spike that captures the ventricle will produce a wide QRS complex, a consistent ST segment and a broad, slurred T wave that is opposite in polarity (direction) from the QRS complex. Do not mistake the wide, slurred after-potential following an external pacing spike for evidence of ventricular depolarization associated with ventricular capture.
Once electrical capture is achieved, the haemodynamic response to pacing also must be confirmed by assessing the patient’s arterial pulse and blood pressure (mechanical capture) during pacing. The pulse rate obtained should match the pacing rate indicated on the generator monitor. A manual count of the pulse rate should be assessed at the right carotid or right femoral artery to avoid confusion between the jerking muscle contractions caused by the pacer and arterial pulse wave. A significantly lower pulse rate than the pacing rate demonstrated on the pacing unit monitor may indicate failure to capture. Continue pacing at an output 10% higher than the threshold of initial electrical capture (the threshold is the minimal pacemaker output associated with consistent pacing capture).
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