Inborn oxidative phosphorylation defect as risk factor for propofol infusion syndrome

Anesthesia management for percutaneous mitral valve repair in a patient with mitochondrial cardiomyopathy and low cardiac function: a case report

BACKGROUND

Mitochondrial cardiomyopathy occurs when impaired mitochondrial energy production leads to myocardial dysfunction. Anesthetic management in such cases is challenging due to risks of circulatory depression associated with anesthesia and mitochondrial dysfunction induced by anesthetics. Although there are reports of anesthetic management for patients with mitochondrial diseases, there are few reports specifically addressing cardiac anesthesia for patients with mitochondrial cardiomyopathy. We present a case where percutaneous mitral valve repair with MitraClip™ was successfully performed under remimazolam anesthesia in a patient with mitochondrial cardiomyopathy who developed functional mitral valve regurgitation due to low cardiac function and cardiomegaly.

CASE PRESENTATION

A 57-year-old woman was diagnosed with chronic cardiac failure, with a 10-year history of dilated cardiomyopathy. She was diagnosed with mitochondrial cardiomyopathy 8 years ago. Over the past 2 years, her cardiac failure worsened, and mitral valve regurgitation gradually developed. Surgical intervention was considered but deemed too risky due to her low cardiac function, with an ejection fraction of 26%. Therefore, percutaneous MitraClip™ implantation was selected. After securing radial artery and central venous catheterization under sedation with dexmedetomidine, anesthesia was induced with a low dose of remimazolam 4 mg/kg/h. Anesthesia was maintained with remimazolam 0.35-1.0 mg/kg/h and remifentanil 0.1 μg/kg/min. Noradrenaline and dobutamine were administered intraoperatively, and the procedure was completed successfully without circulatory collapse. The patient recovered smoothly from anesthesia and experienced no complications. She was discharged on the eighth day after surgery.

CONCLUSION

Anesthesia management with remimazolam appears to be a safe and effective for MitraClip™ implantation in patients with mitochondrial cardiomyopathy.

Safety of Extended Propofol Infusions in Critically Ill Pediatric Patients

Introduction Propofol is a phenol agent with sedative and anesthetic properties that has been in use for decades, but with controversy in critically ill pediatric patients, given the concern for developing propofol-related infusion syndrome (PRIS). Our aim was to assess the risk of propofol infusions in the pediatric intensive care unit (PICU) at doses and durations greater than the described safety data and its associated covariables. Methods Retrospective cohort analysis of 173 patients receiving propofol in the PICU. Patients were categorized as receiving greater or less than 48-hour infusions. Demographic data and daily clinical variables were recorded for up to seven days post-infusion initiation or until infusion was stopped. Results In this descriptive analysis, patients' demographics were similar, but admission diagnosis was not. Both groups received high mean doses of propofol (>67 mcg/kg/min), with no cases of PRIS observed. The illness severity scores and the need for vasoactive infusion support varied between the cohorts, with higher illness scores and a higher percentage of subjects requiring vasoactive agents in the >48-hour cohort. Finally, there were no major differences in lactate levels or biochemical characteristics between the two groups. Conclusions This study provides pilot data in relation to the feasibility of propofol infusion in critically ill pediatric patients and underscores the need for a larger multicenter study to draw clinical recommendations.

Propofol-Related Infusion Syndrome: A Bibliometric Analysis of the 100 Most-Cited Articles

Propofol-related infusion syndrome (PRIS) is a rare, yet life-threatening sequelae to prolonged administration of the anesthetic propofol in mechanically intubated patients. The condition is characterized by progressive multi-system organ failure and eventual mortality; of note, the predominant characteristics of PRIS involve but are not limited to cardiovascular impairment and collapse, metabolic and lactic acidosis, rhabdomyolysis, hyperkalemia, and acute renal failure. While potent or extended doses of propofol have been found to be the primary precipitating factor of this condition, others such as age, critical illness, steroid therapy, and hyperlipidemia have been discovered to play a role as well. This bibliometric analysis was done to reflect the current relevance and understanding of PRIS in recent literature. The SCOPUS database was utilized to conduct a search for articles with keywords "propofol infusion syndrome" and "propofol syndrome" from February 24, 2001, until April 16, 2023, with parameters for article title, citation number, citation per year, author, institution, publishing journal, and country of origin. PRIS was first defined in 1990, just a year after its approval by the Food and Drug Administration for use as a sedative-hypnotic. Since then, interest in PRIS slowly rose up to 13 publications per year in 2013. Seven papers on the topic were published in Critical Care Medicine, six in Neurocritical Care, and four in Anesthesia. The most common institutions were Mayo Clinic, Northeastern University, and Tufts Medical Center. To our knowledge, this is the first bibliometric analysis to evaluate the most influential publications about PRIS. A majority of the research is case-based, possibly owing to the rarity of the condition. Our research suggests that confounding factors outside the precipitating dosage of propofol may be implicated in the onset and progression of PRIS. This study could therefore bring renewed interest to the topic and lead to additional research focused on fully understanding the pathophysiology of PRIS in order to promote the development of novel diagnostics and treatment.

European Neuromuscular Centre consensus statement on anaesthesia in patients with neuromuscular disorders

BACKGROUND AND PURPOSE

Patients with neuromuscular conditions are at increased risk of suffering perioperative complications related to anaesthesia. There is currently little specific anaesthetic guidance concerning these patients. Here, we present the European Neuromuscular Centre (ENMC) consensus statement on anaesthesia in patients with neuromuscular disorders as formulated during the 259th ENMC Workshop on Anaesthesia in Neuromuscular Disorders.

METHODS

International experts in the field of (paediatric) anaesthesia, neurology, and genetics were invited to participate in the ENMC workshop. A literature search was conducted in PubMed and Embase, the main findings of which were disseminated to the participants and presented during the workshop. Depending on specific expertise, participants presented the existing evidence and their expert opinion concerning anaesthetic management in six specific groups of myopathies and neuromuscular junction disorders. The consensus statement was prepared according to the AGREE II (Appraisal of Guidelines for Research & Evaluation) reporting checklist. The level of evidence has been adapted according to the SIGN (Scottish Intercollegiate Guidelines Network) grading system. The final consensus statement was subjected to a modified Delphi process.

RESULTS

A set of general recommendations valid for the anaesthetic management of patients with neuromuscular disorders in general have been formulated. Specific recommendations were formulated for (i) neuromuscular junction disorders, (ii) muscle channelopathies (nondystrophic myotonia and periodic paralysis), (iii) myotonic dystrophy (types 1 and 2), (iv) muscular dystrophies, (v) congenital myopathies and congenital dystrophies, and (vi) mitochondrial and metabolic myopathies.

CONCLUSIONS

This ENMC consensus statement summarizes the most important considerations for planning and performing anaesthesia in patients with neuromuscular disorders.

Expanding the phenotypic and molecular spectrum of NFS1-related disorders that cause functional deficiencies in mitochondrial and cytosolic iron-sulfur cluster containing enzymes

Iron-sulfur cluster proteins are involved in critical functions for gene expression regulation and mitochondrial bioenergetics including the oxidative phosphorylation system. The c.215G>A p.(Arg72Gln) variant in NFS1 has been previously reported to cause infantile mitochondrial complex II and III deficiency. We describe three additional unrelated patients with the same missense variant. Two infants with the same homozygous variant presented with hypotonia, weakness and lactic acidosis, and one patient with compound heterozygous p.(Arg72Gln) and p.(Arg412His) variants presented as a young adult with gastrointestinal symptoms and fatigue. Skeletal muscle biopsy from patients 1 and 3 showed abnormal mitochondrial morphology, and functional analyses demonstrated decreased activity in respiratory chain complex II and variably in complexes I and III. We found decreased mitochondrial and cytosolic aconitase activities but only mildly affected lipoylation of pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase enzymes. Our studies expand the phenotypic spectrum and provide further evidence for the pathogenicity and functional sequelae of NFS1-related disorders with disturbances in both mitochondrial and cytosolic iron-sulfur cluster containing enzymes.

Lung but not brain cancer cell malignancy inhibited by commonly used anesthetic propofol during surgery: Implication of reducing cancer recurrence risk

Introduction

Intravenous anesthesia with propofol was reported to improve cancer surgical outcomes when compared with inhalational anesthesia. However, the underlying molecular mechanisms largely remain unknown.

Objectives

The anti-tumor effects of propofol and the possible underlying mechanism including altered metabolic and signaling pathways were studied in the current study.

Methods

The cell viability, proliferation, migration, and invasion of cancer cells were analyzed with CCK-8, Ki-67 staining, wound healing, and Transwell assay, respectively. The protein changes were analyzed with Western blot and immunofluorescent staining. The metabolomics alteration was studied with 1H-NMR spectroscopy. The gene expression regulations were analyzed with PCR gene array and qRT-PCR experiments.

Results

In this study, we found that propofol reduced cell viability and inhibited cell proliferation, migration and invasion of lung cancer cells, but not neuroglioma cells. In lung cancer cells, propofol downregulated glucose transporter 1 (GLUT1), mitochondrial pyruvate carrier 1 (MPC1), p-Akt, p-Erk1/2, and hypoxia- inducible factor 1 alpha (HIF-1 α ) expressions and upregulated pigment epithelium-derived factor (PEDF) expression. Propofol increased intracellular glutamate and glycine but decreased acetate and formate whilst increased glucose, lactate, glutamine, succinate, pyruvate, arginine, valine, isoleucine, and leucine and glycerol, and decreased acetate, ethanol, isopropanol in the culture media of lung cancer cells. Furthermore, VEGFA, CTBP1, CST7, CTSK, CXCL12, and CXCR4 gene expressions were downregulated, while NR4A3, RB1, NME1, MTSS1, NME4, SYK, APC, and FAT1 were upregulated following the propofol treatment. Consistent with the phenotypical changes, these molecular and metabolic changes were not found in the neuroglioma cells.

Conclusion

Our findings indicated anti-tumor effects of propofol on the lung cancer but not brain cancer, through the regulation of tumor metastasis-related genes, multi-cellular signaling and cellular metabolism.

Neuroimaging of Propofol Infusion Syndrome: A Case Report and Review of Literature

A school-age boy with a complex medical history underwent a minor elective surgical procedure. Propofol was used for sedation during the procedure. The patient could not be awakened post-operatively. Laboratory findings demonstrated metabolic lactic acidosis, leukocytosis with bandemia, and transaminitis. Neuroimaging demonstrated findings that were consistent with hypoxic-ischemic or toxic-metabolic brain injury involving the bilateral basal ganglia, hippocampi, and cerebellum. The patient's condition progressively worsened over the course of the following few weeks, and brain death was confirmed by scintigraphy seven weeks later. Prompt neuroimaging in unresponsive patients with suspected propofol infusion syndrome (PRIS) is of critical importance in detecting neurologic injuries, excluding alternative diagnoses, and determining prognostication.

Effects of Propofol on Cellular Bioenergetics in Human Skeletal Muscle Cells

OBJECTIVES

Propofol may adversely affect the function of mitochondria and the clinical features of propofol infusion syndrome suggest that this may be linked to propofol-related bioenergetic failure. We aimed to assess the effect of therapeutic propofol concentrations on energy metabolism in human skeletal muscle cells.

DESIGN

In vitro study on human skeletal muscle cells.

SETTINGS

University research laboratories.

SUBJECTS

Patients undergoing hip surgery and healthy volunteers.

INTERVENTIONS

Vastus lateralis biopsies were processed to obtain cultured myotubes, which were exposed to a range of 1-10 μg/mL propofol for 96 hours.

MEASUREMENTS AND MAIN RESULTS

Extracellular flux analysis was used to measure global mitochondrial functional indices, glycolysis, fatty acid oxidation, and the functional capacities of individual complexes of electron transfer chain. In addition, we used [1-C]palmitate to measure fatty acid oxidation and spectrophotometry to assess activities of individual electron transfer chain complexes II-IV. Although cell survival and basal oxygen consumption rate were only affected by 10 μg/mL of propofol, concentrations as low as 1 μg/mL reduced spare electron transfer chain capacity. Uncoupling effects of propofol were mild, and not dependent on concentration. There was no inhibition of any respiratory complexes with low dose propofol, but we found a profound inhibition of fatty acid oxidation. Addition of extra fatty acids into the media counteracted the propofol effects on electron transfer chain, suggesting inhibition of fatty acid oxidation as the causative mechanism of reduced spare electron transfer chain capacity. Whether these metabolic in vitro changes are observable in other organs and at the whole-body level remains to be investigated.

CONCLUSIONS

Concentrations of propofol seen in plasma of sedated patients in ICU cause a significant inhibition of fatty acid oxidation in human skeletal muscle cells and reduce spare capacity of electron transfer chain in mitochondria.

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.

Multidisciplinary Perioperative Care for Children with Neuromuscular Disorders

Children with neuromuscular diseases present unique challenges to providing safe and appropriate perioperative care. Given the spectrum of disease etiologies and manifestations, this is a population that often requires specialized multidisciplinary care from pediatricians, geneticists, neurologists, dieticians, and pulmonologists which must also be coordinated with surgeons and anesthesiologists when these patients present for surgery. Several of these diseases also have specific pharmacologic implications for anesthesia, most notably mitochondrial disease and muscular dystrophies, which put them at additional risk during the perioperative period particularly in patients presenting without a formal diagnosis. Techniques and strategies to fully evaluate and optimize these patients preoperatively, manage them safely intraoperatively, and return them to their baseline status postoperative are particularly important in this vulnerable group of patients. Utilizing a review of inherited neuromuscular conditions, generalized perioperative concerns, and specific complications related to anesthesia, this article provides an overview of pertinent considerations and recommends a framework for management of these patients.

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.

Anesthetic management of a pediatric patient with Electron Transfer Flavoprotein Dehydrogenase deficiency (ETFDH) and acute appendicitis: case report and review of the literature

BACKGROUND

Mitochondria are the energy producing organelles practically in every human cell except erythrocytes. Indeed mitochondria are widespread in high energy requiring organs like brain, heart and muscles. Currently there are no clinical trials supporting with clear evidence which is the most suitable surgical or anesthetic management of a patient with known mitochondrial disease presenting with surgical disorders. This condition poses possible hazardous problems to the medical attention of those patients.

CASE PRESENTATION

A case of an 8 year old child with known Electron Transfer Flavoprotein Dehydrogenase deficiency (ETFDH deficiency) requiring surgery for acute appendicitis is presented. Our approach for anesthesia revealed a combination of fentanyl, low dose propofol and nitrous oxide.

CONCLUSION

The choice of the safest pharmacological anesthetic agents for patients with ETFDH deficiency is challenging given that most of the general anesthetic medications have multiple effects on mitochondria, fatty acids metabolism and striated muscles. Anesthetists are expected to individualize anesthetic care for the patient based on current publications for similar cases, medical history and knowledge of pharmacology and physiology.

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.

Propofol-Related Infusion Syndrome in the Peripartum Period

Background Propofol is a widely known, commonly used drug. Complications can occur with the use of this drug, including propofol-related infusion syndrome (PRIS). PRIS, in the obstetric population, has not been documented; however, we report a case of a patient who developed PRIS after an emergent cesarean delivery of a preterm infant. Case Study A 35-year-old multigravida woman presented complaining of leakage of fluid and decreased fetal movement. Her pregnancy was complicated by methadone maintenance therapy due to a history of opioid abuse. Complications after admission for prolonged monitoring and a prolonged fetal heart tone deceleration was noted with no recovery despite intrauterine resuscitation. An emergent cesarean delivery was performed using general anesthesia and endotracheal intubation after which she developed aspiration pneumonia. She was admitted to the intensive care unit and reintubation and sedation were required secondary to respiratory distress. Sedation was achieved using propofol infusion. She subsequently developed changes in her electrocardiogram, an increase of her serum creatinine, creatinine protein kinase, lipase, amylase, and triglycerides, making the diagnosis of PRIS. Conclusion PRIS should be included in the differential diagnosis of intubated or postoperative patients in the obstetric population.

Perioperative considerations in adult mitochondrial disease: A case series and a review of 111 cases

Mitochondrial disease has been uncommon conditions, still results in death during childhood in many cases. The ideal anesthetic pharmacological management strategy for adult patients with mitochondrial disease is currently unclear. In this study, we presented features of the anesthesia methods employed and the perioperative complications of patients in our institution and in previously published case reports. We report the use of general anesthesia 7 times in 6 adult patients with mitochondrial disease during 2004-2014. All cases were performed with maintained intravenous anesthesia. One case was reintubated on the day after surgery, but the cause of death was not directly related to anesthesia. One hundred and eleven general anesthesia cases in 97 adult patients with mitochondrial disease were described in 83 the literature. Although several severe perioperative complications and deaths have been reported, malignant hyperthermia had not been reported in adult cases, and metabolic disorder called propofol infusion syndrome had also not been reported in adult patients undergone total intravenous anesthesia. Perioperative complications of lactic acidosis were reported more in inhalation anesthesia than intravenous anesthesia. Therefore we recommended intravenous anesthesia rather than inhalation anesthesia for adult mitochondrial disease.

The causes of drug-induced muscle toxicity

PURPOSE OF REVIEW

Clinically identified myopathies are frequently a consequence of medication toxicities. However, recognizing drug-induced myopathies is sometimes difficult. Developing a greater understanding of the underlying mechanisms of drug-induced muscle toxicity will promote enhanced awareness and recognition, and improved management of these syndromes.

RECENT FINDINGS

The adverse impact of certain drugs on muscle metabolism, muscle cell atrophy, and myocyte apoptosis is increasingly clear. Glucocorticoids impair glucose handling and directly promote protein catabolism. Statins impair mitochondrial function and alter intracellular signaling proteins, which can lead to myocyte apoptosis. Alternatively, statins can induce an autoimmune necrotizing myositis. Several medications impair autophagy, thus limiting access to the needed glycogen stores.

SUMMARY

This review provides an overview of the main underlying mechanisms of drug-induced myopathies. These myopathies will most often be related to a drug's ability to alter metabolism and protein balance, induce necrosis, or impair autophagy.

Rhabdomyolysis: a genetic perspective

Rhabdomyolysis (RM) is a clinical emergency characterized by fulminant skeletal muscle damage and release of intracellular muscle components into the blood stream leading to myoglobinuria and, in severe cases, acute renal failure. Apart from trauma, a wide range of causes have been reported including drug abuse and infections. Underlying genetic disorders are also a cause of RM and can often pose a diagnostic challenge, considering their marked heterogeneity and comparative rarity.

In this paper we review the range of rare genetic defects known to be associated with RM. Each gene has been reviewed for the following: clinical phenotype, typical triggers for RM and recommended diagnostic approach. The purpose of this review is to highlight the most important features associated with specific genetic defects in order to aid the diagnosis of patients presenting with hereditary causes of recurrent RM.

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.

Diagnosis and management of mitochondrial disease: a consensus statement from the Mitochondrial Medicine Society

PURPOSE

The purpose of this statement is to review the literature regarding mitochondrial disease and to provide recommendations for optimal diagnosis and treatment. This statement is intended for physicians who are engaged in diagnosing and treating these patients.

METHODS

The Writing Group members were appointed by the Mitochondrial Medicine Society. The panel included members with expertise in several different areas. The panel members utilized a comprehensive review of the literature, surveys, and the Delphi method to reach consensus. We anticipate that this statement will need to be updated as the field continues to evolve.

RESULTS

Consensus-based recommendations are provided for the diagnosis and treatment of mitochondrial disease.

CONCLUSION

The Delphi process enabled the formation of consensus-based recommendations. We hope that these recommendations will help standardize the evaluation, diagnosis, and care of patients with suspected or demonstrated mitochondrial disease.

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.