Death related to propofol use in an adult patient

Direct visualization of general anesthetic propofol on neurons by stimulated Raman scattering microscopy

The consensus for the precise mechanism of action of general anesthetics is through allosteric interactions with GABA receptors in neurons. However, it has been speculated that these anesthetics may also interact with the plasma membrane on some level. Owing to the small size of anesthetics, direct visualization of these interactions is difficult to achieve. We demonstrate the ability to directly visualize a deuterated analog of propofol in living cells using stimulated Raman scattering (SRS) microscopy. Our findings support the theory that propofol is highly concentrated and interacts primarily through non-specific binding to the plasma membrane of neurons. Additionally, we show that SRS microscopy can be used to monitor the dynamics of propofol binding using real-time, live-cell imaging. The strategy used to visualize propofol can be applied to other small molecule drugs that have been previously invisible to traditional imaging techniques

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Multi-modal SRS developed for real-time biological imaging of small molecule substances

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Propofol primarily concentrates at the cell membrane of neurons

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Anesthesia dynamics can be monitored in real-time with SRS

L-Carnitine and Acylcarnitines: Mitochondrial Biomarkers for Precision Medicine

Biomarker discovery and implementation are at the forefront of the precision medicine movement. Modern advances in the field of metabolomics afford the opportunity to readily identify new metabolite biomarkers across a wide array of disciplines. Many of the metabolites are derived from or directly reflective of mitochondrial metabolism. L-carnitine and acylcarnitines are established mitochondrial biomarkers used to screen neonates for a series of genetic disorders affecting fatty acid oxidation, known as the inborn errors of metabolism. However, L-carnitine and acylcarnitines are not routinely measured beyond this screening, despite the growing evidence that shows their clinical utility outside of these disorders. Measurements of the carnitine pool have been used to identify the disease and prognosticate mortality among disorders such as diabetes, sepsis, cancer, and heart failure, as well as identify subjects experiencing adverse drug reactions from various medications like valproic acid, clofazimine, zidovudine, cisplatin, propofol, and cyclosporine. The aim of this review is to collect and interpret the literature evidence supporting the clinical biomarker application of L-carnitine and acylcarnitines. Further study of these metabolites could ultimately provide mechanistic insights that guide therapeutic decisions and elucidate new pharmacologic targets.

The effects of gasotransmitters inhibition on biochemical and haematological parameters and oxidative stress in propofol-anaesthetized Wistar male rats

This study aimed to investigate the effects of propofol through evaluating its interaction with nitric oxide (NO), hydrogen sulfide (H2S), and carbon monoxide (CO). Wistar male rats were divided in 4 groups: (1) bolus injection of propofol (1% 10 mg/mL, 100 mg/kg bw, i.p.); (2) Nω-nitro-l-arginine methyl ester (L-NAME; NO synthase inhibitor, 60 mg/kg bw, i.p.) + bolus injection of propofol (1% 10 mg/mL, 100 mg/kg bw, i.p.); (3) DL-propargylglycine (DL-PAG; H2S synthase inhibitor, 50 mg/kg bw, i.p.) + bolus injection of propofol (1% 10 mg/mL, 100 mg/kg bw, i.p.); (4) zinc protoporphyrin IX (ZnPPIX; CO synthase inhibitor, 50 μmol/kg bw, i.p.) + bolus injection of propofol (1% 10 mg/mL, 100 mg/kg bw, i.p.). Increased levels of albumins, low-density lipoproteins, alkaline phosphatase, amylase, high-sensitivity Troponin T, and fibrinogen were found in L-NAME + propofol group. Platelet crit, platelet count, total cholesterol, and high-density lipoproteins were elevated in ZnPPIX + propofol group. Hydrogen peroxide was increased in all groups treated with gasotransmitters inhibitors. Reduced glutathione was reduced in all groups, superoxide dismutase activity only in L-NAME + propofol. The effect of propofol on various biochemical, haematological, and oxidative stress markers may be at least in part mediated through interaction with 3 estimated gasotransmitters.

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.

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.

Effects of different doses of dexmedetomidine on heart rate and blood pressure in intensive care unit patients

The aim of the present study was to observe and compare the sedative effect of different doses of DEX on heart rate (HR) and blood pressure (BP) in critically ill patients admitted to intensive care units (ICUs). The study included patients that were retained in ICUs and required sedation between January and March 2014. Patients were excluded if they had a BP of >200 mmHg, a HR of <60 bpm or were in a state of shock. The included patients were randomized into three groups: Group A, 1.0 µg/kg/10 min DEX; group B, 0.5 µg/kg/10 min DEX; and group C, 0.4 µg/kg/h DEX. After receiving these initial designated doses of DEX via an intravenous (IV) infusion pump for 10 min, the patients were maintained continuously at an identical dose of 0.4 µg/kg/h DEX. Ramsay score, HR, systolic blood pressure (SBP), diastolic blood pressure (DBP), breathing rate (BR) and peripheral capillary oxygen saturation (SpO₂) were recorded prior to the IV pump infusion and at 2, 4, 6, 8, 10, 60, 120, 180 and 240 min following infusion. Patients in groups A and B achieved sedation more rapidly compared with those in group C (P<0.05). HR decreased more significantly at 8 and 60 min after the initial IV pump infusion with DEX in groups A and B compared with group C (P<0.05). SBP decreased significantly at 10 min after IV pump infusion in group A compared with groups B and C (P<0.05). No significant difference existed in the SBP reduction trend between the three groups during the maintenance period. Therefore, the routine dose of DEX (0.4 µg/kg/h) provides an ideal sedative effect in ICU patients. The recommended loading dose for a more rapid sedation is 0.5 µg/kg/h. High loading doses of DEX via IV pump infusion should be avoided in elderly individuals, patients with acute exacerbation of chronic obstructive pulmonary disease and anemic patients, in whom combination medication, such as midazolam or propofol, may be considered when necessary.

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.

PRIS may be diagnosed before ICU period for patients undergoing cardiopulmonary bypass

There are many published articles on the clinical manifestations of propofol-related infusion syndrome (PRIS), but they are not the same in each case.(1)Moreover, PRIS is only encountered infrequently and, therefore, it may create a diagnostic challenge. Nearly all of the published articles on PRIS are related to the use of long-term (> 48 hour) propofol infusion with a dose range of at least 4-5 mg/kg/h. In this case, not only a short duration, but also a low-dose propofol administration seems to induce PRIS. A 73-year-old male patient under cardiopulmonary bypass (CPB) suffered from some clinical symptoms of PRIS, such as hyperlactatemia and persistent low metabolic acidosis which promptly resolved on the discontinuation of propofol. Therefore, we suggest that any propofol administration (bolus or infusion) may result in such clinical symptoms, which may be the earliest indicators of PRIS. When those symptoms are observed on propofol administration during cardiopulmonary bypass (CPB), the perfusionist must alert both the anaesthesiologist and the surgeon to stop the propofol in order to prevent the patient from further adverse effects of PRIS.

Optimizing Sedation Management to Promote Early Mobilization for Critically Ill Children

Achieving successful early mobilization for the intubated, critically ill child is dependent on optimizing sedation and analgesia. Finding the fine balance between oversedation and undersedation can be challenging. The ideal is for a child to be lucid and interactive during the daytime and demonstrate normal circadian rhythm for sleep with rest at night. Being alert during the day facilitates active participation in therapy including potential ambulation, while decreasing the risk of delirium during mechanical ventilation. An active state during the day with frequent mobilization promotes restorative sleep at night, which brings with it multiple benefits for healing and recovery. Indeed, this ideal may not be physiologically feasible given a child's critical illness and trajectory, but defining it as the "gold standard" for early mobilization provides a consistent goal for the pediatric intensive care unit (PICU) hospitalization. As such, goal-directed, patient-specific sedation plans are integral to creating a culture of mobility in the PICU. We review currently available sedation strategies for mechanically ventilated children for successful implementation of early mobilization in the PICU, as well as pharmacologic considerations for specific classes of sedative-analgesics.

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.

Therapeutic plasma exchange as treatment for propofol infusion syndrome

Propofol infusion syndrome (PRIS), a rare complication of propofol sedation, is associated with high mortality. There is no specific therapy. A 16-year-old with head injury and status epilepticus is described. Three days after seizure resolution, whilst receiving propofol, he developed severe lactic acidosis, rhabdomyolysis, and hemodynamic instability. Suspected PRIS was treated with a single session of therapeutic plasma exchange (TPE). This was associated with immediate improvement in hemodynamic status, resolution of lactic acidosis within 24 h, normalization of CPK over 10 days, and a subsequent full recovery. TPE is suggested as a novel therapy for PRIS.

Propofol infusion syndrome: a retrospective analysis at a level 1 trauma center

Objectives. The propofol infusion syndrome (PRIS), a rare, often fatal, condition of unknown etiology, is defined by development of lipemic serum, metabolic acidosis, rhabdomyolysis, hepatomegaly, cardiac arrhythmias, and acute renal failure. Methods. To identify risk factors for and biomarkers of PRIS, a retrospective chart review of all possible PRIS cases during a 1-year period was conducted at a level 1 trauma hospital in ICU patients over 18 years of age receiving continuous propofol infusions for ≥3 days. Additional study inclusion criteria included vasopressor support and monitoring of serum triglycerides and creatinine. Results. Seventy-two patients, 61 males (84.7%) and 11 females (15.3%), satisfied study inclusion criteria; and of these, 3 males met the study definition for PRIS, with 1 case fatality. PRIS incidence was 4.1% with a case-fatality rate of 33%. The mean duration of propofol infusion was 6.96 days. A positive linear correlation was observed between increasing triglyceride levels and infusion duration, but no correlation was observed between increasing creatinine levels and infusion duration. Conclusions. Risk factors for PRIS were confirmed as high dose infusions over prolonged periods. Increasing triglyceride levels may serve as reliable biomarkers of impending PRIS, if confirmed in future investigations with larger sample sizes.

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.

Propofol infusion syndrome in refractory status epilepticus

BACKGROUND AND PURPOSE

Propofol is used for treating refractory status epilepticus, which has high rate of mortality. Propofol infusion syndrome is a rare but often fatal syndrome, characterized by lactic acidosis, lipidemia, and cardiac failure, associated with propofol infusion over prolonged periods of time. We investigated the clinical factors that characterize propofol infusion syndrome to know the risk of them in refractory status epilepticus.

METHODS

This retrospective observation study was conducted in Samsung medical center from Jan. 2005 to Dec. 2009. Thirty two patients (19 males, 13 females, aged between 16 and 64 years), with refractory status epilepsy were included. Their clinical findings and treatment outcomes were evaluated retrospectively. We divided our patients into established status epilepticus (ESE) and refractory status epilepticus (RSE). And then the patients with RSE was further subdivided into propofol treatment group (RSE-P) and the other anesthetics treatment group (RSE-O). We analyzed the clinical characteristics by comparison of the groups.

RESULTS

There were significant differences of hypotension and lipid change between ESE and RSE (p<0.05). However, there was no significant difference between RSE-P and RSE-O groups. The hospital days were longer in RSE than in ESE (p=0.012) and treatment outcome was also worse in RSE than in ESE (p=0.007) but there were no significant differences of hospital stays and treatment outcome between RSE-P and RSE-O.

CONCLUSIONS

RSE is very critical disease with high mortality, which may show as many clinical changes as propofol infusion syndrome. Therefore propofol infusion syndrome might be considered as one of the clinical manifestations of RSE.

Propofol Infusion syndrome during refractory status epilepticus in a young adult: successful ECMO resuscitation

BACKGROUND

Propofol infusion syndrome (PRIS) is a rare but serious complication of propofol administration consisting of metabolic disorder with acidosis, often leading to fatal cardiovascular collapse.

METHODS

A case of PRIS is described in a 17-year-old female with refractory status epilepticus (RSE) who was receiving high-dose propofol for seizure control and sedation.

RESULTS

Metabolic syndrome was observed with renal failure, severe metabolic acidosis, and rhabdomyolysis after 58 h of propofol infusion at a maximum dose of 8.8 mg/kg/h. It was not initially associated with circulatory failure. Propofol was stopped immediately, and brief bradycardia was observed. The patient was started on continuous hemofiltration resulting in correction of the metabolic disorder. However, cardiocirculatory failure occurred a few hours later. Her clinical evolution and biological assessments were typical of PRIS. Extracorporeal membrane oxygenation (ECMO) was initiated despite the presence of cardiocirculatory arrest. Cardiocirculatory function improved rapidly, and the patient was weaned off ECMO after 5 days. No severe neurologic effects were observed, and she left the intensive care unit after 36 days, returning home after 2 months.

CONCLUSIONS

Careful consideration should be given before prescribing propofol as first-line therapy for RSE, and this drug should be avoided altogether if high doses are required. Close biochemical monitoring is needed if propofol is used for more than a few hours, so that PRIS can be recognized promptly. Immediate discontinuation of propofol is essential, and early hemofiltration should be initiated. ECMO should be considered in cases of cardiocirculatory failure.

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.

Propofol infusion syndrome

A review of the history, incidence, presentation, pathophysiology, and treatment of propofol infusion syndrome.

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.

Cardiovascular manifestations of sedatives and analgesics in the critical care unit

There are numerous sedatives and analgesics used in critical care medicine today; these medications are used on critically ill patients, many of whom have heart disease, including coronary artery disease or congestive heart failure. The purpose of this review is to recognize the effects of these medications on the heart. Studies that evaluated the effects of sedatives and analgesics on normal individuals or on those with heart disease were reviewed. Current choices for sustained sedation in the critically ill include the benzodiazepines, morphine, propofol, and etomidate. Each of these medications has their particular advantages and disadvantages. Benzodiazepines provide the greatest amnesia and cardiovascular safety but they can cause significant hypotension in the hemodynamically unstable patient. Morphine provides analgesia and cardioprotective activity after ischemia, although the large observational study CRUSADE showed increased mortality rate in those patients with non-ST segment elevation myocardial infarction who received morphine. Propofol is the most easily titratable drug with cardioprotective features, but its use must be accompanied with great attention to possible development of propofol infusion syndrome, which is a deadly disease, especially in patients with head injury and those with septic shock receiving vasopressors. Etomidate has a rapid onset effect and short period of action with great hemodynamic stability even in patients with shock and hypovolemia, but the incidence of adrenal insufficiency during infusion, not bolus doses, may cause deterioration in the circulatory stability. In conclusion, the sedatives and analgesics mentioned here have characteristics that give them a cardiovascular safety profile useful in critically ill patients. However, use of these drugs on an individual basis is dependent on each agent's safety and efficacy.

Propofol infusion syndrome: case report and literature review

PURPOSE

A case of propofol infusion syndrome in a patient with respiratory failure and sepsis is reported.

SUMMARY

A 36-year-old Hispanic woman was admitted to the medical intensive care unit for treatment of respiratory failure and sepsis, likely secondary to pneumonia. Her medical history included human immunodeficiency virus infection and chronic hepatitis C virus infection. She was intubated and placed on mechanical ventilation. Empirical i.v. antimicrobial therapy was initiated with vancomycin, moxifloxacin, piperacillin-tazobactam, trimethoprim-sulfamethoxazole, and micafungin, along with corticosteroids and vasopressors. Propofol 1.5 mg/kg per hour i.v. and midazolam i.v. were initiated for sedation, but the dosages of both propofol and midazolam needed to be increased due to persistent agitation. On hospital day 7, the patient developed a morbilliform rash on her neck, shoulders, and chest and multiple abnormal laboratory test values, including elevated levels of alanine transaminase, aspartate transaminase, amylase, lipase, creatine kinase, and triglycerides. Serial electrocardiograms revealed sinus tachycardia. Computed tomography of the abdomen showed hepatomegaly with fatty infiltration of the liver, no gallstones, and a normal pancreas. I.V. phenobarbital was added for sedation, and propofol was tapered and discontinued on the same day. The patient responded adequately to phenobarbital maintenance therapy and was eventually weaned off all other sedatives. The patient's laboratory test values returned to normal within 72 hours after discontinuation of the propofol infusion, and the rash and tachycardia resolved.

CONCLUSION

Propofol infusion syndrome developed in a patient with respiratory failure and sepsis after a prolonged infusion of high-dose propofol.

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.

Vasopressors and propofol infusion syndrome in severe head trauma

INTRODUCTION

Propofol infusion syndrome (PRIS) is a rare, but lethal complication of high-dose propofol infusions. We undertook this study to evaluate the incidence of PRIS in a cohort of patients with severe head trauma and its relation to the use of vasopressors.

METHODS

We reviewed all patients with severe head trauma admitted to our Neuro-Intensive Care Unit over a 4-year period for use of propofol and vasopressors. Those patients who developed unexplained acidosis, creatine kinase elevation unrelated to trauma, and electrocardiographic changes were considered having PRIS. We investigated the concomitant use of vasopressors while propofol was used and calculated odds ratios for developing PRIS.

RESULTS

We report three adult patients who developed PRIS out of 50 (6%) admitted patients with severe head trauma on propofol infusions. Two of these patients survived and one expired after withdrawal of life support. Concomitant use of vasopressors was associated with development of PRIS in this cohort (odds ratio 29, 95% CI 1.5-581, P < 0.05).

CONCLUSIONS

Awareness and early recognition of PRIS in critically ill neurosurgical patients on vasopressors and daily screening for creatine kinase elevation, unexplained acidosis, or electrocardiographic changes may reduce the incidence and case-fatality.

Propofol infusion syndrome: an overview of a perplexing disease

Propofol (2, 6-diisopropylphenol) is a potent intravenous hypnotic agent that is widely used in adults and children for sedation and the induction and maintenance of anaesthesia. Propofol has gained popularity for its rapid onset and rapid recovery even after prolonged use, and for the neuroprotection conferred. However, a review of the literature reveals multiple instances in which prolonged propofol administration (>48 hours) at high doses (>4 mg/kg/h) may cause a rare, but frequently fatal complication known as propofol infusion syndrome (PRIS). PRIS is characterized by metabolic acidosis, rhabdomyolysis of both skeletal and cardiac muscle, arrhythmias (bradycardia, atrial fibrillation, ventricular and supraventricular tachycardia, bundle branch block and asystole), myocardial failure, renal failure, hepatomegaly and death. PRIS has been described as an 'all or none' syndrome with sudden onset and probable death. The literature does not provide evidence of degrees of symptoms, nor of mildness or severity of signs in the clinical course of the syndrome. Recently, a fatal case of PRIS at a low infusion rate (1.9-2.6 mg/kg/h) has been reported. Common laboratory and instrumental findings in PRIS are myoglobinuria, downsloping ST-segment elevation, an increase in plasma creatine kinase, troponin I, potassium, creatinine, azotaemia, malonylcarnitine and C5-acylcarnitine, whereas in the mitochondrial respiratory electron transport chain, the activity of complex IV and cytochrome oxidase ratio is reduced. Propofol should be used with caution for sedation in critically ill children and adults, as well as for long-term anesthesia in otherwise healthy patients, and doses exceeding 4-5 mg/kg/h for long periods (>48 h) should be avoided. If PRIS is suspected, propofol must be stopped immediately and cardiocirculatory stabilization and correction of metabolic acidosis initiated. So, PRIS must be kept in mind as a rare, but highly lethal, complication of propofol use, not necessarily confined to its prolonged use. Furthermore, the safe dosage of propofol may need re-evaluation, and new studies are needed.

Medication-related complications in the trauma patient

Trauma patients are twice as likely to have adverse reactions to medication as nontrauma patients. The need for medication in trauma patients is high. Surgery is often necessary, and immunosuppression and hypercoagulability may be present. Adverse drug events can be caused in part by altered pharmacokinetics, drug interactions, and polypharmacy. Medications may also have serious long-term adverse effects, which must be considered. It is not the purpose of this review article to discuss all adverse effects of all medications. This article will discuss the more common adverse effects of medications for trauma patients in the acute care setting, in the following categories: pain control, sedation, antibiotics, seizure prophylaxis in head trauma, atrial fibrillation, deep vein thrombosis and pulmonary embolism prophylaxis, hemodynamic support, adrenal insufficiency, factor VIIa.

Propofol-related infusion syndrome in intensive care patients

The Institute of Medicine has identified adverse drug events as factors that significantly contribute to increased patient morbidity and mortality. As critically ill patients receive numerous drugs to treat a multitude of complicated health problems, they are at high risk for adverse drug events. Sedation is often a key requirement for the optimal management of critical illness, and propofol, a common sedative, has many desirable characteristics that make it the ideal agent in numerous circumstances. However, over the last decade, increasing numbers of reports have described a potentially fatal adverse effect called propofol-related infusion syndrome. Whether this adverse drug event is preventable is unclear, but recommendations have been proposed to minimize the potential for development of this syndrome. Research is under way to collect data on the use of propofol in intensive care units and on its prevalence.

[Propofol infusion syndrome]

The propofol infusion syndrome is a rare but potentially lethal complication resulting from a prolonged continuous administration of propofol. It was first described in the beginning of the 1990's and in recent years there have been frequent reports of problems in association with the use of propofol sedation. The cardinal signs and symptoms of the propofol infusion syndrome are metabolic acidosis, rhabdomyolysis, renal failure, cardiac arrhythmias and a progressive, often therapy-resistant cardiac failure. The pathophysiology of this syndrome appears to involve a disturbance of mitochondrial metabolism induced by propofol. Our report involves a case of propofol infusion syndrome in a patient having undergone cardiac surgery.

Propofol infusion syndrome

The clinical features of propofol infusion syndrome (PRIS) are acute refractory bradycardia leading to asystole, in the presence of one or more of the following: metabolic acidosis (base deficit > 10 mmol.l(-1)), rhabdomyolysis, hyperlipidaemia, and enlarged or fatty liver. There is an association between PRIS and propofol infusions at doses higher than 4 mg.kg(-1).h(-1) for greater than 48 h duration. Sixty-one patients with PRIS have been recorded in the literature, with deaths in 20 paediatric and 18 adult patients. Seven of these patients (four paediatric and three adult patients) developed PRIS during anaesthesia. It is proposed that the syndrome may be caused by either a direct mitochondrial respiratory chain inhibition or impaired mitochondrial fatty acid metabolism mediated by propofol. An early sign of cardiac instability associated with the syndrome is the development of right bundle branch block with convex-curved ('coved type') ST elevation in the right praecordial leads (V1 to V3) of the electrocardiogram. Predisposing factors include young age, severe critical illness of central nervous system or respiratory origin, exogenous catecholamine or glucocorticoid administration, inadequate carbohydrate intake and subclinical mitochondrial disease. Treatment options are limited. Haemodialysis or haemoperfusion with cardiorespiratory support has been the most successful treatment.

Critical care sedation for neuroscience patients

In 2000, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) introduced the mandate for the implementation of standards for both pain assessment and need for therapy in hospitalized patients. The need for the appropriate titration of sedation and analgesia is particularly poignant in an intensive care unit (ICU) setting where iatrogenic discomfort often complicates patient management. Neurologically ill patients in ICUs present particularly complex sedation issues, owing to the need to monitor these patients with serial neurological exams. Hence, maximal comfort without diminishing neurological responsiveness is desirable. Here, we review the frequently applied methods of evaluating levels of pain and agitation in critically ill patients as well as discuss the appropriate classes of pharmaceutical agents common to this population, with particular emphasis on the potential neurophysiological impact of such therapy.

UK drug analysis prints and anaesthetic adverse drug reactions

PURPOSE

Anaesthetic drugs were selected from the Medicines and Healthcare products Regulatory Agency Drug Analysis Prints in order to determine the number and types of reported reactions and associated mortality.

METHODS

The chosen drug groups were the intravenous induction agents, the neuromuscular blocking drugs and neostigmine, the inhalational anaesthetic agents and nitrous oxide, local anaesthetic agents and a selection of analgesics agents, naloxone and midazolam and its antagonist flumazenil. From each drug file, the number and type of reactions were analysed. Mortality was calculated as a percentage of the number of deaths against patient reports.

RESULTS

A total of 11,199 reactions were analysed from 6603 patients of whom 620 (9%) died. Few drug records reported reactions from multiple constituent formulations. The majority of reactions were not allergic. The highest mortality was in the inhalational anaesthetic group. Although the greatest number of fatal events was associated with halothane, this drug is no longer used. Nevertheless the percentage remains high because cardiovascular mortality is still being reported. Local anaesthetic use was associated with the smallest percentage mortality (3%). The highest reported number of reactions was associated with the intravenous induction agents and idiosyncratic neurological and peripheral vascular reactions were linked with the use of etomidate.

CONCLUSIONS

The reporting of allergic reactions was low. The data demonstrate that induction of anaesthesia presents the highest risk of adverse drug reaction; there is also mortality from newer drugs for example, desflurane, remifentanil as well as from drugs for which there is no alternative, for example, suxamethonium.

Propofol-associated fatal myocardial failure and rhabdomyolysis in an adult with status epilepticus

Propofol is increasingly used for the treatment of status epilepticus due to the ease of use and tolerability, even if safety data from randomized clinical trials are lacking. An association of high infusion rates of propofol (>5 mg/kg/h) for more than 48 h and constellation of acidosis, rhabdomyolysis, and cardiovascular collapse has been reported in children, but has only been described in a few adult cases. We report a case and autopsy findings of an adult who developed rhabdomyolysis and cardiac failure after receiving propofol for status epilepticus. The patient became symptomatic within 55 h after initiation of propofol infusion. The maximal infusion rate did not exceed 7.2 mg/kg/h, and propofol in excess of 5mg/kg/h was infused for less than 20 h. Preexisting antiepileptic medication may have exacerbated acidosis. Propofol infusion for the treatment of status epilepticus should be carefully weighted against its real risk to develop propofol infusion syndrome, and alternative agents such as benzodiazepines or barbiturates should be considered for first line therapy. If necessary, prolonged propofol infusion at high doses for the treatment of status epilepticus should be used with caution, and in all cases careful monitoring for rhabdomyolysis and acidosis must be performed.

Lethal self administration of propofol (Diprivan). A case report and review of the literature

The death of a female anaesthesiologist is reported. Although the situation at the scene indicated propofol overdose-related death, self-administration of such high doses of propofol was unlikely, given the pharmacological properties of this drug. The analysis of the situation at the scene and the toxicological analysis in which the blood and liver propofol concentrations were 2.40microg/ml and 0.56microg/g, respectively, supported the conclusion that the death was a consequence of propofol self-administration at therapeutic doses from a person who used the drug on chronic basis seeking to its euphoric effects. However, because the toxic concentrations of propofol in non-intubated patients may be different from those intubated and fully supported in the operating room or in the intensive care unit, a mere interpretation of the blood and tissue concentrations of propofol in the toxicological analysis can confirm the drug intake but it may be of limited diagnostic significance without taking into account this difference.

Propofol infusion syndrome in a patient with sepsis

Propofol is widely used for sedation in critically ill patients. Several adult patients, all with acute neurological disorders, have been reported suffering from propofol infusion syndrome, which occurs in patients receiving high-dose propofol and catecholamines and/or steroids. We present a case of a septic patient without neurological illness who developed propofol infusion syndrome.

Propofol Infusion Syndrome: A Case of Increasing Morbidity With Traumatic Brain Injury

A previously healthy 16-year-old boy with a closed, severe traumatic brain injury was admitted to a surgical and trauma intensive care unit. He was given a continuous infusion of propofol for sedation and to control intracranial pressure. About 3 days after the propofol infusion was started, metabolic acidosis and rhabdomyolysis developed. Acute renal failure ensued as a result of the rhabdomyolysis. Tachycardia with wide QRS complexes developed without hyperkalemia. The patient died of refractory cardiac dysrhythmia and circulatory collapse approximately 36 hours after the first signs of propofol infusion syndrome appeared. Propofol infusion syndrome is a rare but frequently fatal complication in critically ill children who are given prolonged high-dose infusions of the drug. The syndrome is characterized by severe metabolic acidosis, rhabdomyolysis, acute renal failure, refractory myocardial failure, and hyperlipidemia. Despite several publications on the subject in the past decade, most cases still seem to remain undetectable.

Propofol infusion syndrome

In this article, we present the case of a previously well 31-year-old man who sustained a mild closed-head injury following a motor vehicle incident and was admitted to the intensive care unit of a major teaching hospital. The man was sedated using propofol combined with midazolam and morphine as the main sedating agent. The propofol was started and continued at high dose for 8 days, over which time the patient deteriorated with metabolic acidosis, rhabdomyolysis, renal impairment, and cardiovascular collapse and then died. A forensic autopsy was performed. The only positive autopsy finding was a cardiac perivascular and interstitial infiltrate of mononuclear cells. The clinical and pathological features in the case presented were consistent with propofol infusion syndrome. No other cause for the above features was found and the cause of death was given as death related to propofol infusion syndrome.Propofol infusion syndrome is characterized by metabolic acidosis, rhadbomyolysis, and myocardial failure, sometimes with renal failure and hyperkalemia occurring in the setting of high-dose propofol treatment. The syndrome has become increasingly recognized in recent years. The syndrome is of importance to forensic pathologists who may see cases referred to their practice because of the unexplained deterioration of a patient in the intensive care unit and the association with head-injured patients and the pediatric population. Death associated with propofol infusion has not been described in the forensic literature.

Survival of propofol infusion syndrome in a head-injured patient

OBJECTIVE

To describe the clinical progression of an adult patient with traumatic brain injury who survived propofol infusion syndrome.

DESIGN

Case report.

SETTING

Tertiary care surgical intensive care unit.

PATIENT

A 21-yr-old male with traumatic brain injury was administered high doses of propofol for sedation and intracranial pressure control combined with vasopressor therapy to maintain cerebral perfusion pressure >60 mmHg. He developed a significant metabolic acidosis with a lactic acid level of 10.9 mmol/L.

INTERVENTIONS

Exploratory laparotomy, discontinuation of propofol infusion.

MEASUREMENTS AND MAIN RESULTS

An exploratory abdominal laparotomy was negative for traumatic injury. During the procedure, the propofol infusion was considered a possible cause and was discontinued. On review, it became apparent that a combination of high-dose propofol and catecholamines were responsible for the lactic acidosis. An echocardiogram revealed severe left ventricular dysfunction and cardiomyopathy, which resolved within 19 days.

CONCLUSIONS

High-dose propofol should be avoided and alternative agents should be instituted for sedation and intracranial pressure management. The use of catecholamine infusions to maintain cerebral perfusion pressure in the setting of a high-dose propofol infusion may be pharmacologically unsound and may be a triggering factor for propofol infusion syndrome. Identification of the syndrome and discontinuation of propofol resulted in complete reversal of symptoms in the case described.