Lactic acidemia and bradyarrhythmia in a child sedated with propofol

Propofol Sedation Washouts in Critically Ill Infants: A Case Series

Medically complex infants are experiencing longer hospital stays, more invasive procedures, and increasingly involved therapeutic interventions that often require long-term analgesia and sedation. This is most commonly achieved with continuous intravenous infusions of opioids and benzodiazepines. There are times when patients develop a tolerance for these medications or the clinical scenario necessitates a rapid wean of them. A rapid wean of either class of medication can lead to increased signs of pain and agitation or withdrawal symptoms. As a result, when a rapid wean is needed or there has been a failure to control symptoms with conventional measures, alternative therapies are considered. Propofol, a sedative hypnotic typically used for general anesthesia and procedural sedation, is one such medication. It has effectively been used for short-term sedation in adults and children to facilitate weaning benzodiazepines and opioids. There is a paucity of data on the use of propofol in infants for this purpose. Here we describe the use of propofol to rapidly wean high-dose sedation and analgesia medications, a propofol sedation washout, in 3 infants. The washouts proved to be safe and efficacious. Based on institutional experience and a literature review, considerations and recommendations are made for propofol sedation washouts in infants.

Effects of coenzyme Q10 in a propofol infusion syndrome model of rabbits

Background

Coenzyme Q (CoQ) might be the main site of interaction with propofol on the mitochondrial respiratory chain in the propofol infusion syndrome (PRIS) because of the structural similarity between coenzyme Q10 (CoQ10) and propofol.

Aim

To investigate the effects of CoQ10 on survival and organ injury in a PRIS model in rabbits.

Methods

Sixteen male New Zealand white rabbits were divided into 4 groups: (1) propofol infusion group, (2) propofol infusion and CoQ10, 100 mg/kg was administered intravenously, (3) sevoflurane inhalation was administered, and (4) sevoflurane inhalation and CoQ10, 100 mg/kg intravenously, was administered. Arterial blood gas and biochemical analyses were repeated every 2 h and every 12 h, respectively. Animals that were alive on the 24th hour after anesthesia induction were euthanized. The organ damages were investigated under light and transmission electron microscopy (TEM).

Results

The propofol infusion group had the highest troponin T levels when compared with the other three groups at the 12th hour. The propofol + CoQ10 group had lower troponin T levels when compared with the propofol and sevoflurane groups (P < 0.05). Administration of CoQ10 decreased total liver injury scores and total organ injury scores both in the propofol and sevoflurane groups. The propofol and sevoflurane organ toxicities were attenuated with CoQ10 in liver, gallbladder, urinary bladder, and spleen.

Conclusion

The addition of CoQ10 to propofol and sevoflurane anesthesia prevented the propofol-associated increase in troponin T levels at the 12th hour of infusion and decreased anesthetic-induced total liver and organ injury scores.

Propofol toxicity in the developing mouse heart mitochondria

BACKGROUND

Propofol infusion syndrome (PRIS) is a potentially lethal consequence of long-term propofol administration. Children are vulnerable and cardiac involvement is often prominent and associated with mortality. We aimed to determine the mechanism of propofol toxicity in newborn mice, hypothesizing that propofol would induce discrete defects within immature cardiac mitochondria.

METHODS

Newborn murine cardiac mitochondria were exposed to propofol or intralipid in vitro. Non-exposed mitochondria served as controls. Mitochondrial respiration and membrane potential (ΔΨ) were measured and respiratory chain complex kinetics were determined.

RESULTS

Propofol and intralipid exerted biological activity in isolated mitochondria. Although intralipid effects were a potential confounder, we found that propofol induced a dose-dependent increase in proton leak and caused a defect in substrate oxidation at coenzyme Q (CoQ). These impairments prevented propofol-exposed cardiomyocyte mitochondria from generating an adequate ΔΨ. The addition of the quinone analog, CoQ₀, blocked propofol-induced leak and increased Complex II+III activity.

CONCLUSIONS

Propofol uncoupled immature cardiomyocyte mitochondria by inducing excessive CoQ-sensitive leak and interfered with electron transport at CoQ. The findings provide new insight into the mechanisms of propofol toxicity in the developing heart and may help explain why children are vulnerable to developing PRIS.

IMPACT

Propofol uncouples immature cardiomyocyte mitochondria by inducing excessive coenzyme Q (CoQ)-sensitive proton leak. Propofol also interferes with electron transport at the level of CoQ. These defects provide new insight into propofol toxicity in the developing heart.

Hypertriglyceridemia may contribute to stroke and pancreatitis: A case report and review of the literature

Hypertriglyceridemia (HTG) is one of the most common clinical dyslipidemia. Nevertheless, stroke and acute pancreatitis co-occurrence due to hypertriglyceridemia are extremely rare. We present a case of hypertriglyceridemia-associated stroke and pancreatitis in a 39-year-old woman. The patient's laboratory tests reported high triglyceride concentrations beyond the instrument's detection range, and radiological examination showed typical signs of cerebral infarction and acute pancreatitis. The patient received combined blood purification therapy, intravenous thrombolysis with urokinase, and conservative treatment of pancreatitis. We discuss the clinical features, pathogenesis, diagnosis, and treatment of hypertriglyceridemic stroke and pancreatitis combined with the relevant literature. We reviewed the mechanisms by which triglycerides contribute to atherosclerosis and acute pancreatitis. We point out the superiority of combined blood purification therapy and caution physicians about the effects of prescribed drugs on blood lipids.

The effect of adenosine triphosphate on propofol-induced myopathy in rats: a biochemical and histopathological evaluation

Propofol infusion syndrome characterized by rhabdomyolysis, metabolic acidosis, kidney, and heart failure has been reported in long-term propofol use for sedation. It has been reported that intracellular adenosine triphosphate (ATP) is reduced in rhabdomyolysis. The study aims to investigate the protective effect of ATP against possible skeletal muscle damage of propofol in albino Wistar male rats biochemically and histopathologically. PA-50 (n = 6) and PA-100 (n = 6) groups of animals was injected intraperitoneally to 4 mg/kg ATP. An equal volume (0.5 ml) of distilled water was administered intraperitoneally to the P-50, P-100, and HG groups. One hour after the administration of ATP and distilled water, 50 mg/kg propofol was injected intraperitoneally to the P-50 and PA-50 groups. This procedure was repeated once a day for 30 days. The dose of 100 mg/kg propofol was injected intraperitoneally to the P-100 and PA-100 groups. This procedure was performed three times with an interval of 1 days. Our experimental results showed that propofol increased serum CK, CK-MB, creatinine, BUN, TP I, ALT, AST levels, and muscle tissue MDA levels at 100 mg/kg compared to 50 mg/kg and decreased tGSH levels. At a dose of 100 mg/kg, propofol caused more severe histopathological damage compared to 50 mg/kg. It was found that ATP prevented propofol-induced muscle damage and organ dysfunction at a dose of 50 mg/kg at a higher level compared to 100 mg/kg. ATP may be useful in the treatment of propofol-induced rhabdomyolysis and multiple organ damage.

Basic Biology of Hypoxic Responses Mediated by the Transcription Factor HIFs and its Implication for Medicine

Oxygen (O₂) is essential for human life. Molecular oxygen is vital for the production of adenosine triphosphate (ATP) in human cells. O₂ deficiency leads to a reduction in the energy levels that are required to maintain biological functions. O₂ acts as the final acceptor of electrons during oxidative phosphorylation, a series of ATP synthesis reactions that occur in conjunction with the electron transport system in mitochondria. Persistent O₂ deficiency may cause death due to malfunctioning biological processes. The above account summarizes the classic view of oxygen. However, this classic view has been reviewed over the last two decades. Although O₂ is essential for life, higher organisms such as mammals are unable to biosynthesize molecular O₂ in the body. Because the multiple organs of higher organisms are constantly exposed to the risk of “O₂ deficiency,” living organisms have evolved elaborate strategies to respond to hypoxia. In this review, I will describe the system that governs oxygen homeostasis in the living body from the point-of-view of the transcription factor hypoxia-inducible factor (HIF).

Propofol infusion syndrome: a structured literature review and analysis of published case reports

Propofol infusion syndrome is a rare, potentially fatal condition first described in children in the 1990s and later reported in adults. We provide a narrative review of what is currently known about propofol infusion syndrome, including a structured analysis of all published case reports; child and adult cases were analysed separately as propofol is no longer used for long-term sedation in children. The review contains an update on current knowledge of the pathophysiology of this condition along with recommendations for its diagnosis, prevention, and management. We reviewed 108 publications documenting 168 cases of propofol infusion syndrome. We evaluated clinical features and analysed factors influencing mortality in child and adult cases using separate multivariate analysis models. We used separate multiple linear regression models to analyse relationships between cumulative dose of propofol and the number of features seen and organ systems involved. Lipidaemia, fever, and hepatomegaly occurred more frequently in children than in adults, whilst rhabdomyolysis and hyperkalaemia were more frequent in adults. Mortality from propofol infusion syndrome is independently associated with fever and hepatomegaly in children, and electrocardiogram changes, hypotension, hyperkalaemia, traumatic brain injury, and a mean propofol infusion rate >5 mg kg^-1 h^-1 in adults. The cumulative dose of propofol was associated with an increased number of clinical features and the number of organ systems involved in adult cases only. Clinicians should consider propofol infusion syndrome in cases of unexplained metabolic acidosis, ECG changes, and rhabdomyolysis. We recommend early consideration of continuous haemofiltration in the management of propofol infusion syndrome.

Short-Term Low-Dose Propofol Anaesthesia Associated with Severe Metabolic Acidosis

Propofol-induced metabolic acidosis is well recognised in the paediatric literature, but the existence of such a syndrome in adults remains contentious. In most reported cases, metabolic acidosis complicated prolonged administration of propofol in critically ill patients. We present a case of severe non-fatal reversible metabolic acidosis, without ventilatory depression or hypoxia, related to short-term propofol infusion in an adult during and after coronary artery bypass grafting. We suggest that lactic acidosis occurred in a genetically susceptible patient with an abnormality of mitochondrial function. This report discusses an unusual adverse effect of propofol anaesthesia and sedation and highlights the need for further investigation to define propofol toxicity.

Propofol Infusion Syndrome— Report of an Adult Fatality

This report describes a fatal case of the propofol infusion syndrome in an adult patient being sedated for a closed head injury using high doses of propofol. The features of circulatory collapse, metabolic acidosis, mild rhabdomyolysis and renal impairment are consistent with the syndrome and not readily attributable to alternative aetiologies. Potential mechanisms for the syndrome may relate to antagonism of beta-receptors, impaired myocardial oxygen utilization and a specific disruption to fatty-acid oxidation.

This is the first published Australian case of the propofol infusion syndrome in an adult and should serve as an additional case report to the existing literature highlighting this potentially fatal syndrome in adults.

Propofol Infusion Syndrome: Efficacy of a Prospective Screening Protocol

Propofol infusion syndrome (PIS) is a potentially lethal complication of propofol marked by rhabdomyolysis, metabolic acidosis, and cardiac arrhythmias or collapse. The objective of this study was to determine the effectiveness of a prospective screening protocol to prevent PIS. All trauma patients admitted who received propofol as a continuous infusion were prospectively screened from November 1, 2013 to December 31, 2015. Variables studied included demographics, injury severity, laboratory values, infusion rates, and mortality. Serum creatine phosphokinase (CPK) and lactate were drawn daily. Propofol was stopped for a positive screen defined as an increase in CPK to greater than 5000 IU/L or lactate greater than 4 mmol/L. Positive and negative cohorts were compared. Two hundred and twenty-five patients met the inclusion criteria and 12 patients (5.3%) had propofol stopped because of elevated CPK. No differences were identified in demographics, transfusions, injury severity, hospital length of stay, or propofol dose. The positive screened group had longer intensive care unit length of stay (20 vs 13 days; P = 0.002) and increased vent days (14.5 vs 10 days; P = 0.008). Max serum osmolality (334 vs 305 mosm/kg; P = 0.049) and max serum CPK (6782 vs 1058 IU/L; P < 0.0001) were higher in the positive cohort. No cases of PIS occurred, and mortality (16.7 vs 15.5%; P = 0.999) was not different between the cohorts. The screening protocol was effective in eliminating PIS. Serial CPK evaluations provided an effective screening tool and serum lactate can be dropped from screening.

Suppression of mitochondrial oxygen metabolism mediated by the transcription factor HIF-1 alleviates propofol-induced cell toxicity

A line of studies strongly suggest that the intravenous anesthetic, propofol, suppresses mitochondrial oxygen metabolism. It is also indicated that propofol induces the cell death in a reactive oxygen species (ROS)-dependent manner. Because hypoxia-inducible factor 1 (HIF-1) is a transcription factor which is involved in cellular metabolic reprogramming by modulating gene expressions of enzymes including glycolysis pathway and oxygen utilization of mitochondria, we examined the functional role of HIF-1 activity in propofol-induced cell death. The role of HIF-1 activity on oxygen and energy metabolisms and propofol-induced cell death and caspase activity was examined in renal cell-derived RCC4 cells: RCC4-EV cells which lack von Hippel-Lindau protein (VHL) protein expression and RCC4-VHL cells, which express exogenous VHL, and in neuronal SH-SY5Y cells. It was demonstrated that HIF-1 is involved in suppressing oxygen consumption and facilitating glycolysis in cells and that the resistance to propofol-induced cell death was established in a HIF-1 activation-dependent manner. It was also demonstrated that HIF-1 activation by treatment with HIFα-hydroxylase inhibitors such as n-propyl gallate and dimethyloxaloylglycine, alleviated the toxic effects of propofol. Thus, the resistance to propofol toxicity was conferred by HIF-1 activation by not only genetic deletion of VHL but also exposure to HIFα-hydroxylase inhibitors.

Propofol induces a metabolic switch to glycolysis and cell death in a mitochondrial electron transport chain-dependent manner

The intravenous anesthetic propofol (2,6-diisopropylphenol) has been used for the induction and maintenance of anesthesia and sedation in critical patient care. However, the rare but severe complication propofol infusion syndrome (PRIS) can occur, especially in patients receiving high doses of propofol for prolonged periods. In vivo and in vitro evidence suggests that the propofol toxicity is related to the impaired mitochondrial function. However, underlying molecular mechanisms remain unknown. Therefore, we investigated effects of propofol on cell metabolism and death using a series of established cell lines of various origins, including neurons, myocytes, and trans-mitochondrial cybrids, with defined mitochondrial DNA deficits. We demonstrated that supraclinical concentrations of propofol in not less than 50 μM disturbed the mitochondrial function and induced a metabolic switch, from oxidative phosphorylation to glycolysis, by targeting mitochondrial complexes I, II and III. This disturbance in mitochondrial electron transport caused the generation of reactive oxygen species, resulting in apoptosis. We also found that a predisposition to mitochondrial dysfunction, caused by a genetic mutation or pharmacological suppression of the electron transport chain by biguanides such as metformin and phenformin, promoted propofol-induced caspase activation and cell death induced by clinical relevant concentrations of propofol in not more than 25 μM. With further experiments with appropriate in vivo model, it is possible that the processes to constitute the molecular basis of PRIS are identified.

Cytotoxicity of propofol in human induced pluripotent stem cell-derived cardiomyocytes

Purpose

Propofol infusion syndrome (PRIS) is a lethal condition caused by propofol overdose. Previous studies suggest that pathophysiological mechanisms underlying PRIS involve mitochondrial dysfunction; however, these mechanisms have not been fully elucidated. This study aimed to establish an experimental model of propofol-induced cytotoxicity using cultured human induced pluripotent stem cell (iPSC)-derived cardiomyocytes to determine the mechanisms behind propofol-induced mitochondrial dysfunction, and to evaluate the protective effects of coenzyme Q10 (CoQ10).

Methods

Human iPSC-derived cardiomyocytes were exposed to propofol (0, 2, 10, or 50 µg/ml) with or without 5 µM CoQ10. Mitochondrial function was assessed by measuring intracellular ATP, lactate concentrations in culture media, NAD⁺/NADH ratio, and the mitochondrial membrane potential. Propofol-induced cytotoxicity was evaluated by analysis of cell viability. Expression levels of genes associated with mitochondrial energy metabolism were determined by PCR. Intracellular morphological changes were analyzed by confocal microscopy.

Results

Treatment with 50 µg/ml propofol for 48 h reduced cell viability. High concentrations of propofol (≥ 10 µg/ml) induced mitochondrial dysfunction accompanied by downregulation of gene expression of PGC-1alpha and its downstream targets (NDUFS8 and SDHB, which are involved in the respiratory chain reaction; and CPT1B, which regulates beta-oxidation). Cardiomyocytes co-treated with 5 µM CoQ10 exhibited resistance to propofol-induced toxicity through recovery of gene expression.

Conclusions

Propofol-induced cytotoxicity in human iPSC-derived cardiomyocytes may be associated with mitochondrial dysfunction via downregulation of PGC-1alpha-regulated genes associated with mitochondrial energy metabolism. Co-treatment with CoQ10 protected cardiomyocytes from propofol-induced cytotoxicity.

Anesthesia and bariatric surgery gut preparation alter plasma acylcarnitines reflective of mitochondrial fat and branched-chain amino acid oxidation

The period around bariatric surgery offers a unique opportunity to characterize metabolism responses to dynamic shifts in energy, gut function, and anesthesia. We analyzed plasma acylcarnitines in obese women (n = 17) sampled in the overnight fasted/postabsorptive state approximately 1-2 wk before surgery (condition A), the morning of surgery (prior restriction to a 48-h clear liquid diet coupled in some cases a standard polyethylene glycol gut evacuation: condition B), and following induction of anesthesia (condition C). Comparisons tested if 1) plasma acylcarnitine derivatives reflective of fatty acid oxidation (FAO) and xenometabolism would be significantly increased and decreased, respectively, by preoperative gut preparation/negative energy balance (condition A vs. B), and 2) anesthesia would acutely depress markers of FAO. Acylcarnitines associated with fat mobilization and FAO were significantly increased in condition B: long-chain acylcarnitines (i.e., C18:1, ~70%), metabolites from active but incomplete FAO [i.e., C14:1 (161%) and C14:2 (102%)] and medium- to short-chain acylcarnitines [i.e., C2 (91%), R-3-hydroxybutyryl-(245%), C6 (45%), and cis-3,4-methylene-heptanoyl-(17%), etc.]. Branched-chain amino acid markers displayed disparate patterns [i.e., isobutyryl-(40% decreased) vs. isovaleryl carnitine (51% increased)]. Anesthesia reduced virtually every acylcarnitine. These results are consistent with a fasting-type metabolic phenotype coincident with the presurgical "gut preparation" phase of bariatric surgery, and a major and rapid alteration of both fat and amino acid metabolism with onset of anesthesia. Whether presurgical or anesthesia-associated metabolic shifts in carnitine and fuel metabolism impact patient outcomes or surgical risks remains to be evaluated experimentally.

Sedation Analgesia and Neuromuscular Blockade in Pediatric Critical Care: Overview and Current Landscape

Sedation is a mainstay of therapy for critically ill children. Although necessary in the care of the critically ill child, sedative drugs are associated with adverse effects, such as disruption of circadian rhythm, altered sleep, delirium, potential neurotoxicity, and immunosuppression. Optimal approaches to the sedation of the critically ill child should include identification of sedation targets and sedation interruptions, allowing for a more individualized approach to sedation. Further research is needed to better understand the relationship between critical illness and sedation pharmacokinetics and pharmacodynamics, the impact of sedation on immune function, and the genetic implications on drug disposition and response.

Propofol Is Mitochondrion-Toxic and May Unmask a Mitochondrial Disorder

There are indications that preexisting mitochondrial disorders or beta-oxidation defects predispose for propofol infusion syndrome. This review aimed at investigating if propofol infusion syndrome occurs exclusively in patients with mitochondrial disorder and if propofol can unmask a mitochondrial disorder. Propofol infusion syndrome has been reported in genetically confirmed mitochondrial disorder patients. In addition, muscle biopsy of patients with propofol infusion syndrome revealed complex IV or complex II deficiency. In animal studies propofol disrupted the electron flow along the respiratory chain and decreased complex I, complex II, and complex III of the respiratory chain. In addition, propofol disrupted the permeability transition pore and reduced the mitochondrial membrane potential. In conclusion, propofol is mitochondrion-toxic and mitochondrial disorder patients should not receive propofol in high dosages over a prolonged period of time. Short-term application of propofol should be safe even in mitochondrial disorder patients. Not only does propofol infusion syndrome occur in mitochondrial disorder patients, but mitochondrial disorder patients are likely at higher risk to develop propofol infusion syndrome. Patients who develop propofol infusion syndrome should be screened for mitochondrial disorder. Propofol infusion syndrome is preventable if risk factors are thoroughly assessed, and if long-term propofol is avoided in patients at risk for propofol infusion syndrome.

Drug induced mitochondrial dysfunction: Mechanisms and adverse clinical consequences

Several commonly used medications impair mitochondrial function resulting in adverse effects or toxicities. Drug induced mitochondrial dysfunction may be a consequence of increased production of reactive oxygen species, altered mitochondrial permeability transition, impaired mitochondrial respiration, mitochondrial DNA damage or inhibition of beta-oxidation of fatty acids. The clinical manifestation depends on the specific drug and its effect on mitochondria. Given the ubiquitous presence of mitochondria and its central role in cellular metabolism, drug-mitochondrial interactions may manifest clinically as hepatotoxicity, enteropathy, myelosuppression, lipodystrophy syndrome or neuropsychiatric adverse effects, to name a few. The current review focuses on specific drug groups which adversely affect mitochondria, the mechanisms involved and the clinical consequences based on the data available from experimental and clinical studies. Knowledge of these adverse drug-mitochondrial interactions may help the clinicians foresee potential issues in individual patients, prevent adverse drug reactions or alter drug regimens to enhance patient safety.

Propofol infusion syndrome: a structured review of experimental studies and 153 published case reports

INTRODUCTION

Propofol infusion syndrome (PRIS) is a rare, but potentially lethal adverse effect of a commonly used drug. We aimed to review and correlate experimental and clinical data about this syndrome.

METHODS

We searched for all case reports published between 1990 and 2014 and for all experimental studies on PRIS pathophysiology. We analysed the relationship between signs of PRIS and the rate and duration of propofol infusion causing PRIS. By multivariate logistic regression we looked at the risk factors for mortality.

RESULTS

Knowledge about PRIS keeps evolving. Compared to earlier case reports in the literature, recently published cases describe older patients developing PRIS at lower doses of propofol, in whom arrhythmia, hypertriglyceridaemia and fever are less frequently seen, with survival more likely. We found that propofol infusion rate and duration, the presence of traumatic brain injury and fever are factors independently associated with mortality in reported cases of PRIS (area under receiver operator curve = 0.85). Similar patterns of exposure to propofol (in terms of time and concentration) are reported in clinical cases and experimental models of PRIS. Cardiac failure and metabolic acidosis occur early in a dose-dependent manner, while arrhythmia, other electrocardiographic changes and rhabdomyolysis appear more frequently after prolonged propofol infusions, irrespective of dose.

CONCLUSION

PRIS can develop with propofol infusion <4 mg/kg per hour and its diagnosis may be challenging as some of its typical features (hypertriglyceridaemia, fever, hepatomegaly, heart failure) are often (>95 %) missing and others (arrhythmia, electrocardiographic changes) occur late.

Propofol administration in patients with methylmalonic acidemia and intracellular cobalamin metabolism disorders: a review of theoretical concerns and clinical experiences in 28 patients

BACKGROUND

Methylmalonic acidemia and intracellular cobalamin metabolism disorders represent a heterogeneous group of inborn errors of metabolism. Most patients will require diagnostic and/or therapeutic procedures frequently requiring sedation or anesthetic management due to neurological and neurocognitive impairments. It has been stated that propofol is contraindicated in this population. We report our experience with propofol administration in a large series of patients.

METHODS

Twenty eight patients (14 mut, seven cblC, three cblA, three cblB, one cblG) aged 2-35.6 years enrolled in a natural history study (ClinicalTrials.gov identifier: NCT00078078) and required anesthetics for 39 diagnostic or therapeutic procedures. Data were collected on the anesthetic technique, perianesthetic course, and adverse events related to propofol.

RESULTS

Propofol was used as the sole induction agent in most cases (36/39) and as the primary maintenance agent in all cases. Infusion rates were 100-400 mcg kg(-1) min(-1) (mean = 214). Infusion duration was 60-325 min (mean = 158) and total doses ranged between 270-3610 mg (mean = 1217). Adverse events were recorded in two cases; neither appeared to be related to propofol administration.

CONCLUSIONS

Propofol is an effective, safe induction and maintenance agent for elective short procedures requiring anesthesia in patients with MMA and cobalamin metabolism disorders. Despite multiple comorbidities and propensity toward instability, those affected can receive anesthesia with an acceptable safety profile, if metabolically and hemodynamically stabilized prior to the event.

SYNOPSIS

A review of the perianesthetic records of 28 patients with isolated MMA and intracellular cobalamin metabolism disorders suggests that propofol anesthesia can be administered safely to these patients, in the setting of metabolic stability.

Treatment of Generalized Convulsive Status Epilepticus in Pediatric Patients

Generalized convulsive status epilepticus (GCSE) is one of the most common neurologic emergencies and can be associated with significant morbidity and mortality if not treated promptly and aggressively. Management of GCSE is staged and generally involves the use of life support measures, identification and management of underlying causes, and rapid initiation of anticonvulsants. The purpose of this article is to review and evaluate published reports regarding the treatment of impending, established, refractory, and super-refractory GCSE in pediatric patients.

Propofol infusion syndrome in adults: a clinical update

Propofol infusion syndrome is a rare but extremely dangerous complication of propofol administration. Certain risk factors for the development of propofol infusion syndrome are described, such as appropriate propofol doses and durations of administration, carbohydrate depletion, severe illness, and concomitant administration of catecholamines and glucocorticosteroids. The pathophysiology of this condition includes impairment of mitochondrial beta-oxidation of fatty acids, disruption of the electron transport chain, and blockage of beta-adrenoreceptors and cardiac calcium channels. The disease commonly presents as an otherwise unexplained high anion gap metabolic acidosis, rhabdomyolysis, hyperkalemia, acute kidney injury, elevated liver enzymes, and cardiac dysfunction. Management of overt propofol infusion syndrome requires immediate discontinuation of propofol infusion and supportive management, including hemodialysis, hemodynamic support, and extracorporeal membrane oxygenation in refractory cases. However, we must emphasize that given the high mortality of propofol infusion syndrome, the best management is prevention. Clinicians should consider alternative sedative regimes to prolonged propofol infusions and remain within recommended maximal dose limits.

Possible pathogenic mechanism of propofol infusion syndrome involves coenzyme q

BACKGROUND

Propofol is a short-acting intravenous anesthetic agent. In rare conditions, a life-threatening complication known as propofol infusion syndrome can occur. The pathophysiologic mechanism is still unknown. Some studies suggested that propofol acts as uncoupling agent, others suggested that it inhibits complex I or complex IV, or causes increased oxidation of cytochrome c and cytochrome aa3, or inhibits mitochondrial fatty acid metabolism. Although the exact site of interaction is not known, most hypotheses point to the direction of the mitochondria.

METHODS

Eight rats were ventilated and sedated with propofol up to 20 h. Sequential biopsy specimens were taken from liver and skeletal muscle and used for determination of respiratory chain activities and propofol concentration. Activities were also measured in skeletal muscle from a patient who died of propofol infusion syndrome.

RESULTS

In rats, authors detected a decrease in complex II+III activity starting at low tissue concentration of propofol (20 to 25 µM), further declining at higher concentrations. Before starting anesthesia, the complex II+III/citrate synthase activity ratio in liver was 0.46 (0.25) and in skeletal muscle 0.23 (0.05) (mean [SD]). After 20 h of anesthesia, the ratios declined to 0.17 (0.03) and 0.12 (0.02), respectively. When measured individually, the activities of complexes II and III remained normal. Skeletal muscle from one patient taken in the acute phase of propofol infusion syndrome also shows a selective decrease in complex II+III activity (z-score: -2.96).

CONCLUSION

Propofol impedes the electron flow through the respiratory chain and coenzyme Q is the main site of interaction with propofol.

Update on the 2012 guidelines for the management of pediatric traumatic brain injury - information for the anesthesiologist

Traumatic brain injury (TBI) is a significant contributor to death and disability in children. Considering the prevalence of pediatric TBI, it is important for the clinician to be aware of evidence-based recommendations for the care of these patients. The first edition of the Guidelines for the Acute Medical Management of Severe Traumatic Brain Injury in Infants, Children, and Adolescents was published in 2003. The Guidelines were updated in 2012, with significant changes in the recommendations for hyperosmolar therapy, temperature control, hyperventilation, corticosteroids, glucose therapy, and seizure prophylaxis. Many of these interventions have implications in the perioperative period, and it is the responsibility of the anesthesiologist to be familiar with these guidelines.

Propofol infusion syndrome: a lethal condition in critically injured patients eliminated by a simple screening protocol

Propofol infusion syndrome (PIS) is defined by arrhythmia, rhabdomyolysis, lactic acidosis, and unrecognized leads to death. We sought to determine the incidence of PIS in trauma patients and evaluate the efficacy of a prospective screening protocol in this patient population.

MATERIALS AND METHODS

In Phase I of the before-and-after study (1st January, 2005-31st December, 2005), trauma patients who received propofol were evaluated. Records were reviewed for demographics, injury severity, propofol time, dose, and rates, laboratory values, and adverse events. Patients were identified with PIS based on two of the following criteria: (1) cardiac arrhythmia/collapse, (2) metabolic acidosis, (3) rhabdomyolysis, and (4) acute kidney injury. Phase II (1st January, 2006-31st December, 2011) consisted of a prospective screening protocol (elevated lactate or creatine phosphokinase (CPK)) to identify patients at risk for PIS.

RESULTS

207 patients were identified in Phase I. 6 (2.9%) developed PIS with a 50% mortality. No differences were seen in age, gender, or mechanism. PIS patients were more injured (median ISS 44 vs 26, p=0.04; median head AIS 5 vs 4, p=0.003) and received more propofol (median 50,350 vs 9770 mg, p=0.001) with longer infusion times (413 vs 65 h, p=0.001). Sodium, creatinine, and CPK levels were higher in those that developed PIS (160 vs 145 mmol/L, p=0.001; 4.3 vs 1.1mg/dL, p=0.005; 59,871 vs 520 U/L; p=0.002). Pre-screening PIS incidence was 2.9% (6/207), but after screening (January 2006) the incidence dropped to 0.19% (2/1038, p<0.001).

CONCLUSIONS

PIS is a morbid and lethal entity associated with sedation of critically injured patients. A simple screening procedure utilizing serum CPK (<5000 U/L) can essentially eliminate the development of PIS.

Anesthetic considerations in patients with mitochondrial defects

Mitochondrial disease, once thought to be a rare clinical entity, is now recognized as an important cause of a wide range of neurologic, cardiac, muscle, and endocrine disorders . The incidence of disorders of the respiratory chain alone is estimated to be about 1 per 4-5000 live births, similar to that of more well-known neurologic diseases . High-energy requiring tissues are uniquely dependent on the energy delivered by mitochondria and therefore have the lowest threshold for displaying symptoms of mitochondrial disease. Thus, mitochondrial dysfunction most commonly affects function of the central nervous system, the heart and the muscular system . Mutations in mitochondrial proteins cause striking clinical features in those tissues types, including encephalopathies, seizures, cerebellar ataxias, cardiomyopathies, myopathies, as well as gastrointestinal and hepatic disease. Our knowledge of the contribution of mitochondria in causing disease or influencing aging is expanding rapidly . As diagnosis and treatment improve for children with mitochondrial diseases, it has become increasingly common for them to undergo surgeries for their long-term care. In addition, often a muscle biopsy or other tests needing anesthesia are required for diagnosis. Mitochondrial disease represents probably hundreds of different defects, both genetic and environmental in origin, and is thus difficult to characterize. The specter of possible delayed complications in patients caused by inhibition of metabolism by anesthetics, by remaining in a biochemically stressed state such as fasting/catabolism, or by prolonged exposure to pain is a constant worry to physicians caring for these patients. Here, we review the considerations when caring for a patient with mitochondrial disease.

Potential for Infra-Nodal Heart Block and Cardiogenic Shock With Propofol Administration

We report a case of infra-nodal complete heart block and cardiogenic shock in a previously healthy 64-year-old man after administration of 180 mg of intravenous Propofol. Although bradycardia, hypotension, and heart block are commonly seen with propofol administration, such findings are transient and respond quickly to administration of vagolytic or sympathomimetic agents suggesting an AV nodal mechanism of heart block. Sustained left ventricular systolic dysfunction and cardiogenic shock by an alternative, non-autonomic mechanism has also been described in the setting of Propofol administration. Our case is the first to note sustained complete infra-nodal heart block in this setting. Early recognition of such a complication, restoration of atrio-ventricular (A-V) synchrony with dual chamber pacing, and aggressive circulatory support is essential in bridging such patients to recovery.

Anesthesia with propofol induces insulin resistance systemically in skeletal and cardiac muscles and liver of rats

Hyperglycemia together with hepatic and muscle insulin resistance are common features in critically ill patients, and these changes are associated with enhanced inflammatory response, increased susceptibility to infection, muscle wasting, and worsened prognosis. Tight blood glucose control by intensive insulin treatment may reduce the morbidity and mortality in intensive care units. Although some anesthetics have been shown to cause insulin resistance, it remains unknown how and in which tissues insulin resistance is induced by anesthetics. Moreover, the effects of propofol, a clinically relevant intravenous anesthetic, also used in the intensive care unit for sedation, on insulin sensitivity have not yet been investigated. Euglycemic hyperinsulinemic clamp study was performed in rats anesthetized with propofol and conscious unrestrained rats. To evaluate glucose uptake in tissues and hepatic glucose output [(3)H]glucose and 2-deoxy[(14)C]glucose were infused during the clamp study. Anesthesia with propofol induced a marked whole-body insulin resistance compared with conscious rats, as reflected by significantly decreased glucose infusion rate to maintain euglycemia. Insulin-stimulated tissue glucose uptake was decreased in skeletal muscle and heart, and hepatic glucose output was increased in propofol anesthetized rats. Anesthesia with propofol induces systemic insulin resistance along with decreases in insulin-stimulated glucose uptake in skeletal and heart muscle and attenuation of the insulin-mediated suppression of hepatic glucose output in rats.

Rare, potentially fatal, poorly understood propofol infusion syndrome

We present the case of a 7-year old boy with traumatic brain injury who received propofol during 38 h. Thirty-six hours after cessation of propofol infusion asystole occurred. After immediate mechanical and medical resuscitation, unreactive dilated pupils were observed. The following computed tomography scan revealed a generalized brain edema with transtentorial herniation. Prolonged bradyarrhythmia, rhabdomyolysis, and peracute renal failure were observed. Despite immediate craniectomy, barbiturate treatment, hemofiltration, and recovery of appropriate cardiac function, the patient died four days after discontinuation of propofol. In this case, metabolic acidosis, cardiac failure, rhabdomyolysis, and renal failure are in accordance with the symptoms of propofol infusion syndrome (PRIS), while seizure, brain edema, and transtentorial herniation could be caused by traumatic brain injury. However, it may be assumed that the entire clinical picture was caused by PRIS. This view could be explained by a common loss of function of ryanodine receptors in patients presenting with PRIS.

Inborn oxidative phosphorylation defect as risk factor for propofol infusion syndrome

Propofol is an anesthetic agent widely used for induction and maintenance of anesthesia, and sedation in children. Although generally considered as reliable and safe, administration of propofol can occasionally induce a potentially fatal complication known as propofol infusion syndrome (PRIS). Mitochondrial dysfunction has been implicated in the pathogenesis of PRIS. We report on an adult patient with Leber hereditary optic neuropathy (LHON) who developed PRIS. He was a carrier of the m.3460G>A mutation, one of the major three pathogenic point mutations associated with LHON. The propositus was blind and underwent propofol sedation after severe head injury. Five days after start of propofol infusion, the patient died. The activity of complex I of the oxidative phosphorylation (OXPHOS) system was severely deficient in skeletal muscle. Our observation indicates that fulminate PRIS can occur in an adult patient with an inborn OXPHOS defect and corroborates the hypothesis that PRIS is caused by inhibition of the OXPHOS system.

Lactate-to-pyruvate ratio as a marker of propofol infusion syndrome after subarachnoid hemorrhage

BACKGROUND

Propofol infusion syndrome (PRIS) is a rare but frequently fatal condition. It is characterized by cardiovascular collapse and metabolic derangement due to propofol exposure. The pathophysiology of PRIS is poorly understood, and its study has previously been limited to animal models and clinical observations. We present the first in vivo brain biochemical data in a patient with PRIS.

METHODS

We report the case of a 37-year-old woman with PRIS following aneurysmal subarachnoid hemorrhage who was monitored by cerebral microdialysis (CMD). A CMD catheter was inserted into the brain and provided near real-time monitoring of brain energy-related metabolites, including lactate and pyruvate, during the time period surrounding the diagnosis of PRIS. We recorded propofol exposure, clinical manifestations, and relevant laboratory measurements.

RESULTS

CMD revealed a temporal association between propofol exposure and the cerebral lactate-to-pyruvate ratio (LPR). The LPR increased linearly after propofol was restarted following an off period, and the LPR decreased linearly after propofol was discontinued. Serum lactate correlated with clinical worsening after the onset of PRIS, whereas cerebral LPR correlated with propofol exposure.

CONCLUSIONS

Cerebral LPR may be a sensitive marker of PRIS. Increases in LPR following propofol exposure should alert clinicians to the possibility of PRIS and might prompt early discontinuation of propofol thereby avoiding fatal complications.

Analytic Reviews: Propofol Infusion Syndrome in the ICU

Propofol is an alkylphenol derivative named 2, 6, diisopropylphenol and is a potent intravenous short-acting hypnotic agent. It is commonly used as sedation, as well as an anesthetic agent in both pediatric and adult patient populations. There have been numerous case reports describing a constellation of findings including metabolic derangements and organ system failures known collectively as propofol infusion syndrome (PRIS). Although there is a high mortality associated with PRIS, the precise mechanism of action has yet to be determined. The best preventive measure for this syndrome is awareness and avoidance of clinical scenarios associated with development of PRIS. There is no established treatment for PRIS; care is primarily supportive in nature and may include the full array of advanced cardiopulmonary support, including extracorporeal membrane oxygenation (ECMO). This article reviews the reported cases of PRIS and describes the current understanding of the underlying pathophysiology and treatment options.

Review of propofol and auxiliary medications used for sedation

The sedative-hypnotic propofol (2,6-diisopropylphenol) is being increasingly used for sedation during painful diagnostic and therapeutic procedures in adults and children. The purpose of this article is to present a general overview of the use of propofol for endoscopic sedation. Advantages and disadvantages of using propofol for sedation, as well as its pharmacokinetics, preparation for use, dosing for endoscopic sedation, auxiliary sedative and analgesic medication options, methods of administering, adverse effects with interventions, recovery, and patient-physician satisfaction are discussed. Finally, next steps necessary to optimize future use of propofol are suggested.

Dark green discoloration of the urine after prolonged propofol infusion: a case report

WHAT IS KNOWN AND OBJECTIVE

Propofol, a commonly used sedative, has on rare occasions, been reported to discolour urine green. However, in previous reports, it is uncertain that whether this colour change is dose dependent. We report on a patient who produced dark green discoloration of urine from prolonged propofol infusion, administered for intractable epilepsy.

CASE SUMMARY

The colour intensity of the patient's urine was dependent on propofol infusion rate. Reducing propofol infusion rate lightened the colour of the urine, eventually back to normal.

WHAT IS NEW AND CONCLUSION

Green discoloration of the urine from propofol infusion is dose dependent. It is usually benign and reversible, as was the case for our patient.

[Anesthesiologic care of children with neurologic trauma]

Neurotrauma is a leading cause of childhood mortality. Physicians are in a continuous search for means to decrease mortality and morbidity caused by head injury. Treatment of these patients requires familiarity with both cerebral pathophysiology and actions of anaesthetic agents on brain. Early treatment of hypotension and hypoventilation would cut mortality rate by at least one third. Prevention of increased intracranial pressure is the best treatment for head injury. Anaesthetist, neurosurgeon and radiologist should all be members of a team which can secure timely diagnosis and treatment of an injured child. Paying attention to every detail is of huge significance. Treatment of the child in a pediatric trauma center or an accident and emergencies center for adults with both personnel and equipment capable for handling paediatric patients offers greater probability of survival.

Sedation and analgesia in children with developmental disabilities and neurologic disorders

Sedation and analgesia performed by the pediatrician and pediatric subspecialists are becoming increasingly common for diagnostic and therapeutic purposes in children with developmental disabilities and neurologic disorders (autism, epilepsy, stroke, obstructive hydrocephalus, traumatic brain injury, intracranial hemorrhage, and hypoxic-ischemic encephalopathy). The overall objectives of this paper are (1) to provide an overview on recent studies that highlight the increased risk for respiratory complications following sedation and analgesia in children with developmental disabilities and neurologic disorders, (2) to provide a better understanding of sedatives and analgesic medications which are commonly used in children with developmental disabilities and neurologic disorders on the central nervous system.

Partial-exchange blood transfusion: an effective method for preventing mortality in a child with propofol infusion syndrome

Here we describe a case of propofol-related infusion syndrome (PRIS) in a child with malignant refractory status epilepticus treated with partial-exchange blood transfusion (PEBT), an innovative method of resuscitation that has the potential to reduce the mortality rate associated with this syndrome. Our patient is a 4-year-old boy with malignant status epilepticus associated with bacterial meningitis. Propofol was used because of persistent seizure activity refractory to adequate doses of phenytoin, phenobarbital, levetiracetam, and midazolam infusion at 0.7 mg/kg per hour. Propofol was escalated from 0.6 mg/kg per hour to an electroencephalogram-burst-suppressing dose of 15.6 mg/kg per hour. Signs of PRIS were noticed after 48 hours on propofol. The severe bradycardia responded only to infusions of calcium gluconate. PEBT corrected all the cardiac abnormalities and returned enough hemodynamic stability to permit continuous veno-venous hemodialysis for renal failure and removal of toxins. PEBT is a safe and innovative option for correcting the metabolic abnormalities that result in cardiac dysfunction, which is typically the most serious and usually terminal event in PRIS. When done with small aliquots, it avoids the severe hemodynamic instability that is usually a hindrance with hemodialysis, continuous veno-venous hemodialysis, and extracorporeal membrane oxygenation, which are other methods of supporting these children during the crisis that are mentioned in the literature.

A Rare Case of Propofol-Induced Acute Liver Failure and Literature Review

The incidence of drug-induced acute liver failure is increasing. A number of drugs can inhibit mitochondrial functions, alter β-oxidation and cause accumulation of free fatty acids within the hepatocytes. This may result in hepatic steatosis, cell death and liver injury. In our case, propofol, an anesthetic drug commonly used in adults and children, is suspected to have induced disturbance of the mitochondrial respiratory chain, which in consequence led to insufficient energy supply and finally liver failure. We report the case of a 35-year-old Caucasian woman with acute liver failure after anesthesia for stripping of varicose veins. Liver histology, imaging and laboratory data indicate drug-induced acute liver failure, presumably due to propofol. Hepatocyte death and microvesicular fatty degeneration of 90% of the liver parenchyma were observed before treatment with steroids. Six months later, a second biopsy was performed, which revealed only minimal steatosis and minimal periportal hepatitis. We suggest that propofol led to impaired fatty acid oxidation possibly due to a genetic susceptibility. This caused free fatty acid accumulation within hepatocytes, which presented as hepatocellular fatty degeneration and cell death. Large scale hepatocyte death was followed by impaired liver function and, consecutively, progressed to acute liver failure.

Incidence of propofol-related infusion syndrome in critically ill adults: a prospective, multicenter study

Introduction

While propofol is associated with an infusion syndrome (PRIS) that may cause death, the incidence of PRIS is unknown. Determining the incidence of PRIS and the frequency of PRIS-related clinical manifestations are key steps prior to the completion of any controlled studies investigating PRIS. This prospective, multicenter study sought to determine the incidence of PRIS and PRIS-related clinical manifestations in a large cohort of critically ill adults prescribed propofol.

Methods

Critically ill adults from 11 academic medical centers administered an infusion of propofol for [>/=] 24 hours were monitored at baseline and then on a daily basis until propofol was discontinued for the presence of 11 different PRIS-associated clinical manifestations and risk factors derived from 83 published case reports of PRIS.

Results

Among 1017 patients [medical (35%), neurosurgical (25%)], PRIS (defined as metabolic acidosis plus cardiac dysfunction and [>/=] 1 of: rhabdomyolysis, hypertriglyceridemia or renal failure occurring after the start of propofol therapy) developed in 11 (1.1%) patients an average of 3 (1-6) [median (range)] days after the start of propofol. While most (91%) of the patients who developed PRIS were receiving a vasopressor (80% initiated after the start of propofol therapy), few received a propofol dose >83 mcg/kg/min (18%) or died (18%). Compared to the 1006 patients who did not develop PRIS, the APACHE II score (25 +/- 6 vs 20 +/- 7, P = 0.01) was greater in patients with PRIS but both the duration of propofol use (P = 0.43) and ICU length of stay (P = 0.82) were similar.

Conclusions

Despite using a conservative definition for PRIS, and only considering new-onset PRIS clinical manifestations, the incidence of PRIS slightly exceeds 1%. Future controlled studies focusing on evaluating whether propofol manifests the derangements of critical illness more frequently than other sedatives will need to be large. These studies should also investigate the mechanism(s) and risk factors for PRIS.

Update on the propofol infusion syndrome in ICU management of patients with head injury

PURPOSE OF REVIEW

The propofol infusion syndrome is a rare condition characterized by the occurrence of lactic acidosis, rhabdomyolysis and cardiovascular collapse following high-dose propofol infusion over prolonged periods of time. Patients with traumatic brain injury are particularly at risk of developing this complication because large doses of propofol are commonly used to control intracranial pressure, whereas vasopressors are administered to augment cerebral perfusion pressure. In this review, we provide an update on the literature with particular emphasis on patients with traumatic brain injury.

RECENT FINDINGS

Several new case reports and reviews, as well as a number of experiments, have contributed significantly to our increased understanding of the cause of the syndrome. At the basis of the syndrome lies an imbalance between energy utilization and demand resulting in cell dysfunction, and ultimately necrosis of cardiac and peripheral muscle cells. Uncertainty remains whether a genetic susceptibility exists. Nonetheless, the growing number of case reports has made it possible to identify several risk factors.

SUMMARY

Propofol infusion syndrome is a rare but frequently lethal complication of propofol use. In patients with risk factors, such as traumatic brain injury, it is suggested that an infusion rate of 4 mg/kg per hour should not be exceeded. Early warning signs include unexplained lactic acidosis, lipemia and Brugada-like ECG changes. When these occur, propofol infusion should be discontinued immediately.