Propofol

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This phenomenon usually occurs in the setting of propofol being administered by infusion in at least a moderately high dose. However, it is a benign phenomenon and is not thought to be associated with an increased risk of propofol infusion syndrome or other badness.

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Propofol infusion syndrome (PRIS) is a potentially lethal condition that can occur in patients receiving a propofol infusion at high dose (e.g. >4mg/kg/h) for a prolonged duration (e.g. >29h). It was first described in children but can also occur in critically ill adults and may occur at lower doses.

The criteria for clinically diagnosing PRIS include:

• Cardiac dysfunction -  especially arrhythmia (such as sudden onset of marked bradycardia resistant to treatment, leading to asystole) and hypotension

and one of:

• Rhabdomyolysis
• Acute renal failure
• Hypertriglyceridemia

Although other features may also be present:

• Unexplained metabolic acidosis
• Lactic acidosis
• Hepatomegaly

The mechanism for PRIS remains obscure as does its true incidence.

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Routine monitoring for biochemical markers such as serum lactate, creatine kinase, myoglobin, and triglycerides has been advocated for early detection of PRIS. However, even twice-daily evaluations of these laboratory studies – with immediate discontinuation of propofol if derangements are detected – may not be protective. Nevertheless, early discontinuation of propofol may lead to recovery.

The development of a Brugada-like ECG pattern (right bundle branch block with convex-curved ST segment elevation in the right precordial leads) has been noted in some cases of PRIS but the utility of this finding is unclear.

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