Death related to propofol use in an adult patient

The syndrome of irreversible acidosis after prolonged propofol infusion

INTRODUCTION

Propofol infusion syndrome is described in the pediatric literature as metabolic acidosis, rhabdomyolysis, and bradycardia that results in death. The pathogenesis of this syndrome is thought to be activation of the systemic inflammatory response, which culminates in acidosis and muscle necrosis.

MATERIALS AND METHODS

Retrospective chart review of three patients in the Neurological Critical Care Units at Hahnemann and Massachusetts General Hospitals between October 2001 and September 2004.

RESULTS

Patient 1: A 27-year-old woman had seizures secondary to hemorrhage from an arteriovenous malformation. Propofol coma was induced for sedation. After initiation of propofol, she developed a metabolic acidosis, hypotension, and bradycardia and expired. Patient 2: A 64-year-old man presented in status epilepticus. After prolonged propofol administration, he developed metabolic acidosis, hypotension, and rhabdomyolysis and expired. Patient 3: A 24-year-old woman presented in status epilepticus secondary to encephalitis. Propofol was added for seizure control. She developed hypotension, metabolic acidosis, and bradyarrhythmias. Despite transvenous pacing, she expired.

CONCLUSION

These data show an association between extended propofol use and metabolic acidosis, rhabdomyolysis, and death in adults, as well as children. Risk factors for propofol infusion syndrome in adults include lean body mass index, high dose, and administration of more than 24-hour duration. Creatine phosphokinase, lactic acid levels, electrolytes, and arterial blood gases should be monitored frequently. Both bacterial and fungal cultures should be obtained. If this syndrome is suspected, hemodialysis should be considered. In fatal cases, autopsy should include electron microscopy of cardiac and skeletal muscle to look for mitochondrial dysfunction. Further study is warranted.

A lethal complication of propofol

High-dose propofol infusion for sedation of patients in the intensive care unit can result in rhabdomyolysis, acute renal failure, metabolic acidosis, hyperkalemia, ventricular arrhythmia, hyperthermia, and death. The death of a patient with such complications after lung biopsy is reported. Until a safer dosage range has been determined, propofol infusion at rates higher than 5 mg x kg(-1) x h(-1) should be discouraged for long-term sedation (> 48 h).

Propofol Infusion Syndrome Associated with Short-Term Large-Dose Infusion During Surgical Anesthesia in an Adult

In this case report we describe a case of propofol infusion syndrome in an adult after a short-term infusion of large-dose propofol during a neurosurgical procedure. Large-dose propofol (9 mg.kg(-1).h(-1)) was given for only 3 h during surgery and was followed by a small-dose infusion (2.3 mg.kg(-1).h(-1)) for 20 h postoperatively. The patient had also received large doses of methylprednisolone. He developed a marked lactic acidosis with mild biological signs of renal impairment and rhabdomyolysis but no cardiocirculatory failure. There were no other evident causes of lactic acidosis as documented by laboratory data. We believe this is the first report of reversible lactic acidosis associated with a short duration of large-dose propofol anesthesia.

Propofol infusion syndrome: an unusual cause of renal failure

Propofol infusion syndrome has been increasingly recognized as a syndrome of unexplained myocardial failure, metabolic acidosis, and rhabdomyolysis with renal failure. It has been described only with acute neurologic injury or acute inflammatory diseases complicated by severe infections or sepsis. It appears to develop in the context of high-dose, prolonged propofol (100 microg/kg/min) treatment in combination with catecholamines and/or steroids. This was first noted in children but is increasingly recognized in adults. This is a case report of 2 patients (a 42-year-old man and a 17-year-old girl) who had acute renal failure associated with use of propofol in the appropriate clinical setting. It examines the pathophysiology and the possible mechanisms of this condition and illustrates the need to consider it as the cause of rhabdomyolysis and acute renal failure in critically ill patients.

Analgesie und Sedierung in der Intensivmedizin

Sedation and analgesia are relevant aspects for the adequate treatment of patients in an intensive care unit. Recent drug developments and new strategies for ventilation provide improved sedation management allowing better adaptation to the clinical background and individual needs of the patient. This article provides an overview on the application of different substance groups. Focus is placed on newly developed pharmaceuticals such as dexmedetomidine. Another aspect is scoring system-related and EEG-based monitoring of depth of sedation. Modern concepts of analgesia and sedation for ICU patients have been developed based on the interaction of different parameters such as adaptive sedation and analgesia management (ASAM).

Propofol-Infusionssyndrom

Propofol infusion syndrome has not only been observed in patients undergoing long-term sedation with propofol, but also during propofol anesthesia lasting 5 h. It has been assumed that the pathophysiologic cause is propofol's impairment of oxidation of fatty acid chains and inhibition of oxidative phosphorylation in the mitochondria, leading to lactate acidosis and muscular necrosis. It has been postulated that propofol might act as a trigger substrate in the presence of priming factors. Severe diseases in which the patient has been exposed to high catecholamine and cortisol levels have been identified as trigger substrates. Once the development of propofol infusion syndrome is suspected, propofol infusion has to be stopped immediately and specific therapeutic measures initiated, including cardiocirculatory stabilization and correction of metabolic acidosis. To increase elimination of propofol and its potential toxic metabolites, hemodialysis or hemofiltration are recommended. Due to its possible fatal side effects, the use of propofol for long-term sedation in critically ill patients should be reconsidered. In cases of unexplained lactate acidosis occurring during continuous propofol infusion, propofol infusion syndrome must be taken into consideration.

Propofol treatment of refractory status epilepticus: a study of 31 episodes

PURPOSE

Refractory status epilepticus (RSE) is a critical medical condition with high mortality. Although propofol (PRO) is considered an alternative treatment to barbiturates for the management of RSE, only limited data are available. The aim of this study was to assess PRO effectiveness in patients with RSE.

METHODS

We retrospectively considered all consecutive patients with RSE admitted to the medical intensive care unit (ICU) between 1997 and 2002 treated with PRO for induction of EEG-monitored burst suppression. Subjects with anoxic encephalopathy showing pathological N20 on somatosensory evoked potentials were excluded.

RESULTS

We studied 31 RSE episodes in 27 adults (16 men, 11 women; median age, 41.5 years). All patients received PRO, and six also subsequently thiopental (THP). Clonazepam (CZP) was administered with PRO, and other antiepileptic drugs (AEDs) concomitant with PRO and THP. RSE was successfully treated with PRO in 21 (67%) episodes and with THP after PRO in three (10%). Median PRO injection rate was 4.8 mg/kg/h (range, 2.1-13), median duration of PRO treatment was 3 days (range, 1-9), and median duration of ICU stay was 7 days (range, 2-42). In 24 episodes in which the patient survived, shivering after general anesthesia was seen in 10 episodes, transient dystonia and hyperlipemia in one each, and mild neuropsychological impairment in five. The seven deaths were not directly related to PRO use.

CONCLUSIONS

PRO administered with CZP was effective in controlling most of RSE episodes, without major adverse effects. In this setting, PRO may therefore represent a valuable alternative to barbiturates. A randomized trial with these drug classes could definitively assess their respective role in RSE treatment.

A case of propofol toxicity: further evidence for a causal mechanism

A 5-month-old boy required sedation after a cleft lip repair. He was sedated with propofol and intermittent fentanyl, requiring escalating doses over the subsequent 48 h. On the second post-operative day he developed a metabolic acidosis followed by multiple cardiac dysrhythmias, hepatic and renal failure. Propofol was stopped. His multisystem organ failure gradually resolved after initiation of charcoal haemoperfusion. Further investigation demonstrated an abnormality in acylcarnitine metabolism, similar to that found in one previous case report.

Short-term propofol infusion as an adjunct to extubation in burned children

Children who require intubation as a component of their burn management generally need heavy sedation, usually with a combination of opiate and benzodiazepine infusions with a target sensorium of light sleep. When extubation approaches, the need for sedation to prevent uncontrolled extubation can conflict with the desire to lighten sedation enough to ensure that airway protective reflexes are strong. The several hours' half-life of these medications can make this period of weaning challenging. Therefore, the hours preceding extubation are among the most difficult in which to ensure safe adequate sedation. The pharmacokinetics of propofol allow for the rapid emergence of a patient from deep sedation. We have had success with an extubation strategy using short-term propofol infusions in critically ill children. In this work, children were maintained on morphine and midazolam infusions per our unit protocol, escalating doses as required to maintain comfort. Approximately 8 hours before planned extubation, these infusions were decreased by approximately half and propofol infusion added to maintain a state of light sleep. Extubation was planned approximately 8 hours later to allow ample time for the chronically infused opiates and benzodiazepines to be metabolized down to the new steady-state level. Thirty minutes before planned extubation, propofol was stopped while morphine and midazolam infusions were maintained at the reduced level. When the children awakened from the propofol-induced state of light sleep, they were extubated while the reduced infusions of morphine and midazolam were maintained. These were subsequently weaned slowly, depending on the child's need for ongoing pain and anxiety medication, per our unit protocol to minimize the incidence of withdrawal symptoms. Data are shown in the text as mean +/- standard deviation. These 11 children (eight boys and three girls) had an average age of 6.6 +/- 5.6 years (range, 1.2-13 years), average weight of 36.9 +/- 28.7 kg (range, 9.3-95 kg), and burn size of 43 +/- 21.4% (range, 10-85%). Three children had sustained scald burns and eight had flame injuries with associated inhalation injury. They had been intubated for an average of 12.7 +/- 10.9 (range, 2-33 days). Morphine infusions immediately before the initiation of propofol averaged 0.26 +/- 0.31 mg/kg/hour (range, 0.04-1.29 mg/kg/hr) and midazolam averaged 0.15 +/- 0.16 mg/kg/hr (range, 0.06-0.65 mg/kg/hr). Morphine infusions after beginning propofol and at extubation averaged 0.16 +/- 0.16 (range, 0.04-0.65 mg/kg/hr) and midazolam averaged 0.09 +/- 0.08 mg/kg/hr (range, 0.02-0.32 mg/kg/hr). Propofol doses after initial titration during the first hour of infusion averaged 3.6 +/- 2.9 mg/kg/hr (range, 0.4-8.1 mg/kg/hr). Nine of the 11 children (82%) were successfully extubated on the first attempt. Two required reintubation for postextubation stridor 2 to 6 hours after extubation but were successfully extubated the next day after a short course of steroids, again using the same propofol technique. All were awake at extubation and went on to survive. Morphine and midazolam infusions were gradually weaned, and there were no withdrawal symptoms noted. Although prolonged (days) infusions of propofol have been associated with adverse cardiovascular complications in critically ill young children and should probably be avoided, short-term (in hours) use of the drug can facilitate smooth extubation.

Medication errors involving continuously infused medications in a surgical intensive care unit

OBJECTIVE

To document the incidence of medication errors related to medications administered by continuous infusion.

DESIGN

Observational study.

SETTING

Sixteen-bed surgical intensive care unit.

MEASUREMENTS AND MAIN RESULTS

All continuous infusions in the surgical intensive care unit were evaluated at least once daily for correct flow-sheet charting, concentration, infusion rate, and dose administered, as well as patients' heights and weights (actual, ideal, and "dry"). Collected information was examined to determine the error rate, types of errors occurring, and weight used for dose calculation. Variations inpatient weight measures were compared. Seventy-one patients with 202 total infusions were observed. Errors involving continuously infused medications in our surgical intensive care unit occurred at a rate of 105.9 per 1,000 patient days. For nonweight-based infusions, 94% of doses were delivered correctly. Slightly >10% of the doses administered for weight-based infusions (dose based on dry body weight) were incorrect. Significant differences were found between the weight measurements recorded, but this did not translate into statistically significant differences in the apparent calculated doses delivered.

CONCLUSIONS

Medications delivered by continuous infusion, particularly those that are weight based, can contribute to medication errors in the intensive care unit. A large proportion (87.6%) of doses for weight-based infusions was calculated based on estimated or unreliable admission weights. There were no severe consequences resulting from the errors observed in this 1 month investigation; however, depending on the pharmacokinetic characteristics of the drug being administered, there is a potential to deliver artificially low or high doses resulting in subtherapeutic or adverse effects.

The safe and effective use of propofol sedation in children undergoing diagnostic and therapeutic procedures: experience in a pediatric ICU and a review of the literature

OBJECTIVES

To describe our experience using propofol sedation to facilitate elective diagnostic and therapeutic procedures, and to document the safety profile of propofol in this setting.

DESIGN

Retrospective consecutive case series and review of the literature.

SETTING

Pediatric intensive care unit of a United States Navy tertiary care medical center.

PATIENTS

Children receiving propofol for procedural sedation over an 18-month period.

OUTCOME MEASURES

Descriptive features of sedation including adverse events.

RESULTS

During the study period, 91 children received propofol to facilitate the performance of 110 medical procedures. The mean induction dose was 2.41 mg/kg, the mean infusion rate was 179.3 microg/kg/min, and the mean total dose of propofol administered was 4.23 mg/kg. In all cases, sedation was successfully achieved. The average length of stay in the PICU was 108.4 minutes. Three children (3.3%) had transient episodes of oxygen desaturation that improved with repositioning of the airway. No child required placement of an endotracheal tube. Three (3.3%) children experienced hypotension requiring a decrease in the infusion rate of propofol and a 10-mL/kg bolus infusion of normal saline. No cardiac arrhythmias or adverse neurologic effects secondary to propofol infusion were identified.

CONCLUSIONS

Pediatric intensivists can safely and effectively administer propofol to facilitate the performance of diagnostic and therapeutic procedures outside the operating room setting.

The pathophysiology of propofol infusion syndrome: a simple name for a complex syndrome

Propofol infusion syndrome (PRIS) is a rare and often fatal syndrome described in critically ill children undergoing long-term propofol infusion at high doses. Recently several cases have been reported in adults, too. The main features of the syndrome consist of cardiac failure, rhabdomyolysis, severe metabolic acidosis and renal failure. To date 21 paediatric cases and 14 adult cases have been described. These latter were mostly patients with acute neurological illnesses or acute inflammatory diseases complicated by severe infections or even sepsis, and receiving catecholamines and/or steroids in addition to propofol. Central nervous system activation with production of catecholamines and glucocorticoids, and systemic inflammation with cytokine production are priming factors for cardiac and peripheral muscle dysfunction. High-dose propofol, but also supportive treatments with catecholamines and corticosteroids, act as triggering factors. At the subcellular level, propofol impairs free fatty acid utilisation and mitochondrial activity. Imbalance between energy demand and utilisation is a key pathogenetic mechanism, which may lead to cardiac and peripheral muscle necrosis. Propofol infusion syndrome is multifactorial, and propofol, particularly when combined with catecholamines and/or steroids, acts as a triggering factor. The syndrome can be lethal and we suggest caution when using prolonged (>48 h) propofol sedation at doses higher than 5 mg/kg per h, particularly in patients with acute neurological or inflammatory illnesses. In these cases, alternative sedative agents should be considered. If unsuitable, strict monitoring of signs of myocytolysis is advisable.

Newer pharmacologic agents for procedural sedation of children in the emergency department-etomidate and propofol

Procedural sedation for pediatric patients having painful or anxiety-producing procedures is a necessary but often a daunting task for emergency medicine providers. This article focuses on the two agents that have most recently been described for use in this population-etomidate and propofol. Etomidate is a nonbarbiturate sedative hypnotic agent with no analgesic properties. Its rapid onset of action, short duration of action, and minimal hemodynamic effects make it an attractive agent for use in procedural sedation. Similar to previous adult studies, recent studies have shown that etomidate is both safe and effective in this pediatric population. Propofol is also a sedative hypnotic agent with rapid onset and short duration of action. Typically, it is administered as a bolus injection followed by an infusion. It has long been used for surgical procedures as well as in the intensive care unit setting, but little literature has supported its use in the pediatric emergency department. Recent studies appear to support propofol's use in this setting; however, a significant rate of side effects, including hypoxia, apnea, and decreased blood pressure, may limit its use.

Toxicity of intravenous anaesthetics

Intravenous anaesthetic agents are generally remarkably safe. However, it is clear that propofol infusion syndrome is a real, albeit rare, entity. This often lethal syndrome of metabolic acidosis, acute cardiomyopathy and skeletal myopathy is strongly associated with infusions of propofol at rates of 5 mg/kg/hour and greater for more than 48 hours. There is evidence to support the hypothesis that the syndrome is caused by the failure of free fatty acid metabolism due to inhibition of free fatty acid entry into the mitochondria and also specific sites in the mitochondrial respiratory chain. The syndrome therefore mimics the mitochondrial myopathies. Midazolam causes seizure-like activity in very-low-birthweight premature infants requiring the drug prior to tracheal intubation or during prolonged positive pressure ventilation. This can be successfully reversed with the specific benzodiazepine antagonist flumazenil. Midazolam can also cause paradoxical reactions, including increased agitation, poor co-operation and aggressive or violent behaviour, which has been successfully managed with flumazenil.

Use of propofol infusion in Australian and New Zealand paediatric intensive care units

Despite the risk of propofol infusion syndrome, a rare but often fatal complication of propofol infusion in ventilated children and possibly adults, propofol infusion remains in use in paediatric intensive care units (PICU). This questionnaire study surveys the current pattern of use of this sedative infusion in Australian and New Zealand PICUs. Thirty-three of the 45 paediatric intensive care physicians surveyed (73%), from 12 of the 13 intensive care units, returned completed questionnaires. The majority of practitioners (82%) use propofol infusion in children in PICU, the main indication being for short-term sedation in children requiring procedures. 39% of respondents consider propofol infusion useful in ventilated children requiring longer-term sedation. 67% of paediatric intensivists use maximum infusion doses that may be considered dangerously high (> or = 10 mg/kg/h). Nineteen per cent use propofol infusion for prolonged periods (> 72 hours). A smaller proportion (15%) of respondents indicate that they may use both higher doses and prolonged periods of infusion, a practice likely to lead to a greater chance of serious adverse events. Knowledge of local protocols for the use of propofol infusion is associated with a significantly greater level of monitoring for possible adverse events. We suggest that national guidelines for the use of propofol infusion in children should be developed. These should include clear indications and contraindications to its use, a maximum dose rate and maximum period of infusion, with a ceiling placed on the cumulative dose given and clearly stated minimum monitoring requirements.

Cardiac arrest associated with intravenous propofol during transesophageal echocardiography before DC cardioversion

Transesophageal echocardiography (TEE)-guided cardioversion has been utilized as a feasible alternative to conventional anticoagulation strategies in the management of patients with atrial fibrillation. As such, the use of intravenous sedation protocols using relatively short-acting anesthetics, such as propofol, have gained popularity in the outpatient and inpatient settings for such procedures. The authors report a case of cardiac arrest and electromechanical dissociation associated with the use of intravenous propofol during TEE before direct current cardioversion for atrial fibrillation.

Propofol infusion syndrome in critically ill patients

OBJECTIVE

To describe the clinical presentation of propofol infusion syndrome in critically ill adults.

DATA SOURCES

Clinical literature was accessed through MEDLINE (1966 - March 2001). Key search terms included Diprivan, propofol, and propofol infusion syndrome. Case reports and small case series evaluating the use and toxicity of propofol in sedating critically ill adults were reviewed.

DATA SYNTHESIS

The association between propofol infusion syndrome and death in children secondary to myocardial failure is well documented. However, few data are available regarding the syndrome in critically ill adults. Based on a review of those data, it appears that propofol infusion syndrome can occur in both children and adults. Common clinical features of propofol infusion syndrome may include hyperkalemia, hepatomegaly, lipemia, metabolic acidosis, myocardial failure, and rhabdomyolysis. Although the premise has not been proven, recent published cases appear to demonstrate an association between propofol infusion and death secondary to myocardial failure.

CONCLUSIONS

Until further safety data become available, caution should be exercised when using high-dose (>5 mg/kg/h) and long-term (>48 h) propofol infusion in sedating critically ill adults.

The propofol infusion syndrome in infants and children: can we predict the risk?

Propofol has been an immensely successful anaesthetic induction agent but there is an increasing number of reports of serious complications when it has been used as an infusion to provide sedation for prolonged periods. The first reports involved children who died from intractable myocardial failure preceded by a metabolic acidosis, lipaemic plasma, fatty infiltration of the liver and evidence of muscle damage. As more cases have been reported the association between propofol and the syndrome has become more certain. Recently adult cases have appeared and a metabolic explanation has been suggested. The syndrome has a high mortality and the only effective treatment appears to be dialysis.

Metabolic acidosis, rhabdomyolysis, and cardiovascular collapse after prolonged propofol infusion

The authors present the hospital course of a 13-year-old girl with a closed head injury who received a prolonged infusion of propofol for sedation and, subsequently, died as a result of severe metabolic acidosis, rhabdomyolysis, and cardiovascular collapse. The patient had been treated for 4 days at a referring hospital for a severe closed head injury sustained in a fall from a bicycle. During treatment for elevations of intracranial pressure, she received a continuous propofol infusion (100 microg/kg/min). The patient began to exhibit severe high anion gap/low lactate metabolic acidosis, and was transferred to the pediatric intensive care unit at the authors' institution. On arrival there, the patient's Glasgow Coma Scale score was 3 and this remained unchanged during her brief stay. The severe metabolic acidosis was unresponsive to maximum therapy. Acute renal failure ensued as a result of rhabdomyolysis, and myocardial dysfunction with bizarre, wide QRS complexes developed without hyperkalemia. The patient died of myocardial collapse with severe metabolic acidosis and multisystem organ failure (involving renal, hepatic, and cardiac systems) approximately 15 hours after admission to the authors' institution. This patient represents another case of severe metabolic acidosis, rhabdomyolysis, and cardiovascular collapse observed after a prolonged propofol infusion in a pediatric patient. The authors suggest selection of other pharmacological agents for long-term sedation in pediatric patients.

Anaesthesia for procedures in the intensive care unit

Taking in charge severely ill patients in the intensive care environment to manage complex procedures is a performance requiring highly specific knowledge. Close collaboration between anaesthetists and intensive care specialists is likely to improve the safety and quality of medical care. Three forms of anaesthetic care should be considered in clinical practice: sedation and analgesia; monitored anaesthetic care; and general anaesthesia or conduction block anaesthesia. Even in the field of sedation and analgesia, the anaesthesiologist can offer expertise on new anaesthetic techniques like: the most recent concepts of balanced anaesthesia in terms of pharmacokinetics and dynamics, favouring the use of short-acting agents and of sedative-opioid combinations. New modes of administration and monitoring intravenous anaesthesia have been developed, with potential application in the intensive care unit. These include the use of target-controlled administration of intravenous drugs, and of electroencephalographic signals to monitor the level of sedation.

Long-term propofol infusion and cardiac failure in adult head-injured patients

Five adult patients with head injuries inexplicably had fatal cardiac arrests In our neurosurgical intensive-care unit after the introduction of a sedation formulation containing an increased concentration of propofol. To examine the possible relation further, we did a retrospective cohort analysis of head-injured adults admitted to our unit between 1996 and 1999 who were sedated and mechanically ventilated. 67 patients met the inclusion criteria, of whom seven were judged to have died from propofol-infusion syndrome. The odds ratio for the occurrence of the syndrome was 1.93 (95% CI 1.12-3.32, p=0.018) for every mg/kg per h increase in mean propofol dose above 5 mg/kg per h. We suggest that propofol infusion at rates higher than 5 mg/kg per h should be discouraged for long-term sedation in the intensive-care unit.