What is the syndrome called when propofol infusion causes marked hypertriglyceridemia?

Propofol Infusion Syndrome (PRIS)

The syndrome associated with propofol causing increased triglycerides is called Propofol Infusion Syndrome (PRIS), a rare but potentially lethal condition characterized by metabolic acidosis, hypertriglyceridemia, cardiac dysfunction, and multiple organ failures. 1, 2

Clinical Definition and Presentation

PRIS is defined by the presence of metabolic acidosis plus cardiac dysfunction, along with one or more of the following: rhabdomyolysis, hypertriglyceridemia, or renal failure occurring after propofol initiation. 1, 3

Core Clinical Features

The syndrome manifests with variable but characteristic signs:

• Worsening metabolic acidosis (base deficit >10 mmol/L) 1, 4
• Cardiac manifestations: Acute refractory bradycardia leading to asystole, hypotension requiring increasing vasopressor support, and arrhythmias 1, 2
• Hypertriglyceridemia and lipemia 1, 2
• Rhabdomyolysis 1, 2
• Acute kidney injury and hyperkalemia 1, 2
• Hepatomegaly and liver dysfunction 1, 2
• ECG changes: Right bundle branch block with coved ST-segment elevation in leads V1-V3 (similar to Brugada syndrome pattern) 2, 4

Incidence and Mortality

The incidence of PRIS is approximately 1-1.1% among critically ill patients receiving propofol infusions. 1, 3 However, mortality from PRIS is high, reaching up to 33%, and death may occur even after discontinuing the infusion. 1

Risk Factors and Dosing Thresholds

Traditional High-Risk Parameters

PRIS is classically associated with prolonged administration of high propofol doses (>70 μg/kg/min or >5 mg/kg/h) for greater than 48 hours. 1, 2 However, the syndrome can also occur with low-dose infusions (<4 mg/kg/h). 1, 5, 4

Major Risk Factors

The following factors significantly increase PRIS risk:

• Decreased oxygen delivery to tissues 2
• Serious neurological injury and/or sepsis 2, 5
• High dosages of vasoconstrictors, steroids, or inotropes (particularly when initiated after propofol therapy begins) 2, 3
• Young age 4
• Inadequate carbohydrate intake 4
• Subclinical mitochondrial disease 4

Pathophysiology

The proposed mechanisms include mitochondrial dysfunction, impaired fatty acid oxidation, diversion of carbohydrate metabolism to fat substrates, and propofol metabolite accumulation. 1 These processes lead to direct mitochondrial respiratory chain inhibition or impaired mitochondrial fatty acid metabolism. 4

Clinical Recognition Challenges

The variable presentation, lack of diagnostic specificity, and infrequent occurrence make detection of PRIS difficult. 1 Recent evidence shows that:

• Typical features like hypertriglyceridemia, fever, and hepatomegaly are often missing (>95% of cases). 5
• Cardiac failure and metabolic acidosis occur early in a dose-dependent manner. 5
• Arrhythmias and ECG changes appear more frequently after prolonged infusions, irrespective of dose. 5
• Older patients are now developing PRIS at lower doses than historically reported. 5

Management Algorithm

Early Recognition

Monitor for the following warning signs:

• Increasing propofol dose requirements to maintain constant sedation levels 2
• Onset of metabolic acidosis during propofol administration 2
• Development of right bundle branch block with coved ST elevation 4
• Rising vasopressor requirements 3

Immediate Action

Early recognition and discontinuation of propofol in patients with suspected PRIS are critically important. 1 When PRIS is suspected:

1. Immediately discontinue propofol infusion 1
2. Switch to alternative sedation (e.g., dexmedetomidine or benzodiazepines) 2
3. Provide supportive management including cardiorespiratory support 1, 4
4. Consider hemodialysis or hemoperfusion with cardiorespiratory support (most successful treatment approach) 4

Hypertriglyceridemia Without Full PRIS

Hypertriglyceridemia alone (>400 mg/dL) occurs in approximately 21.7% of patients receiving propofol, typically at 4.5 days after initiation. 6 When this occurs:

• 70.4% of patients still requiring sedation receive alternative sedatives after developing hypertriglyceridemia. 6
• Acute pancreatitis occurs in only 1.2% of all propofol patients, but is more frequent in those with hypertriglyceridemia (3.2% vs 0.7%). 6
• Each 100 mg/dL increase in triglyceride levels is associated with an 11% increase in pancreatitis risk. 6

Monitoring Recommendations

Serum triglycerides should be monitored in patients at risk of hyperlipidemia when propofol is administered for extended periods. 2 Specific thresholds suggesting high risk include:

• Peak triglyceride levels >688 mg/dL 7
• Duration on propofol >4.5 days 7
• Average daily propofol dose >3007 mg/day 7
• Cumulative propofol dose >24,113 mg 7

Lipid Management

When fat is being inadequately cleared, propofol administration should be adjusted and concurrent lipid administration reduced. 2 Remember that 1 mL of propofol contains approximately 0.1 g of fat (1.1 kcal). 2

Critical Pitfalls to Avoid

• Do not assume PRIS only occurs with high doses or prolonged infusions—it can develop at lower doses and shorter durations 1, 5, 4
• Do not wait for all classic features to be present—most typical signs are frequently absent 5
• Do not abruptly discontinue propofol without transitioning to alternative sedation—this causes rapid awakening with anxiety, agitation, and resistance to mechanical ventilation 2
• Do not overlook the early ECG warning sign of right bundle branch block with coved ST elevation 4
• Do not continue propofol when metabolic acidosis develops or dose requirements increase 2