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

Do Patients With Mental Illness Undergoing Office-Based Sedation Require an Increased Propofol Dosage?

BACKGROUND

Providers report needing higher sedative doses to achieve adequate sedation in patients with mental illnesses. These claims, however, have not been thoroughly assessed.

PURPOSE

The purpose of the study was to measure the association between mental illness and the propofol dosage necessary to achieve a satisfactory level of anesthesia.

STUDY DESIGN, SETTING, SAMPLE

The study consisted of a single-center, retrospective cohort consisting of patients treated by oral and maxillofacial surgery at the University of Cincinnati Medical Center in 2020. The study was comprised of subjects 15 or older who were American Society of Anesthesiologists (ASA) classification I or II. Subjects under 15 or ASA III or higher were excluded from the study.

PREDICTOR VARIABLE

The predictor variable was the presence or absence of mental illness.

MAIN OUTCOME VARIABLE(S)

The primary outcome was the total dose of propofol, measured as the total amount of propofol administered divided by the patient's weight in kilograms divided by the length of the procedure in minutes (mg/kg/min). The secondary outcome was the Richmond Agitation-Sedation Scale (RASS) score achieved during sedation.

COVARIATES

Sex, race, ethnicity, age, weight, body mass index, ASA score, prior tobacco use, marijuana use, use of adjunct midazolam, fentanyl, and ketamine during the procedure, and type of procedure served as covariates.

ANALYSES

Test statistics were calculated using the Wilcoxon rank-sum test, Kruskal-Wallis test, Spearman rank correlation test, and χ2 test for bivariate analyses. Linear and logistic regression models were used to estimate association while controlling for confounding. P values ≤ .05 were considered statistically significant.

RESULTS

The study sample was 409 subjects (36.92% male, mean age 28.27 ± 12.20 years). In bivariate analysis, mental illness did not show any association with propofol dose (mean dose with mental illness 150.85 ± 143.97 mg/kg/min, mean dose without mental illness 116.54 ± 104.16, P = .08) or RASS score (sufficiently sedated with mental illness 63.38%, sufficiently sedated without mental illness 58.80%, P = .36). After adjusting for all previously mentioned covariates, mental illness was statistically associated with propofol dose (P < .01). Adjusting for covariates, only sex had a statistically significant association with the RASS score (P < .05).

CONCLUSION AND RELEVANCE

The findings suggest that a patient's mental illness may influence the amount of sedative required to achieve satisfactory anesthesia.

A case of pediatric Perthes' disease with unexplained hyperlactatemia at the time of initial surgery and anesthetic management with remimazolam for the subsequent surgery

BACKGROUND

The causes of perioperative hyperlactatemia vary, but they are generally associated with hypoperfusion. Here, we report the case of a pediatric patient who developed unexplained hyperlactatemia during anesthesia with propofol and sevoflurane, which recurred during a second surgery under anesthesia with remimazolam.

CASE PRESENTATION

An 8-year-old boy with Perthes disease and no remarkable past or family history was scheduled for an osteotomy. Anesthesia was induced with propofol and rocuronium and then maintained with sevoflurane and remifentanil. The patient developed lactic acidosis without hemodynamic instability during anesthesia, with a normal lactate/pyruvate ratio after surgery, suggesting a lack of hypoperfusion. We used remimazolam instead of propofol during the second surgery 6 months later, considering the possibility of drug-induced lactic acidosis, including malignant hyperthermia and propofol infusion syndrome, where the unexplained hyperlactatemia recurred.

CONCLUSIONS

Distinguishing the causes of hyperlactatemia, particularly in the absence of other symptoms, is challenging. The lactate/pyruvate ratio during episodes of hyperlactatemia can provide insights into the underlying pathology.

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.

SAFETY OF PROPOFOL ANESTHESIA DURING NEUROSURGICAL OPERATIONS

OBJECTIVE

The aim: The purpose of this study was to assess the safety of propofol use during neurosurgical operations of different durations.

PATIENTS AND METHODS

Materials and methods: 72 patients were divided into three groups depending on the type of operations; it were group 1 (ventriculostomy), group 2 (hematoma removal), and group 3 (tumor removal), the anesthesia durations in these groups were 65±5 min, 145±7 min and 225±10 min, respectively. Total propofol doses in patients of groups 1, 2, and 3 were 452±22 mg, 710±42 mg, and 966±51 mg, respectively. Before intervention and 1 h post operation, blood gas composition, serum levels of transaminase, triglycerides, creatine phosphokinase, and potassium, rate of urine output, level of mean arterial pressure, and heart rhythm rate were determined.

RESULTS

Results: No significant deviations concerning hemodynamic indicators, blood gas composition, changes of creatine kinase activity were found for any group patients during the perioperative period. The rate of urine output in all patients reached above 0.5 ml/kg/h without saluretics use. The deviated transaminase values returned to their normal ones during 24 h post intervention. The triglycerides levels were in normal range proving the absence of propofol doses used on the lipid metabolism.

CONCLUSION

Conclusions: Anesthetic protection of neurosurgical interventions using propofol in doses 2.5-3 mg/kg and 3.60.3 mg/kg/h for induction anesthesia and for anesthesia support, respectively, is safe and does not lead to dangerous undesired consequences. However, the propofol use for prolonged patient sedation and his/her adaptation for prolonged lung ventilation needs further studies.

Comparison of remimazolam-based and propofol-based total intravenous anesthesia on postoperative quality of recovery: A randomized non-inferiority trial

STUDY OBJECTIVE

The quality of recovery (QoR) of remimazolam-based and propofol-based total intravenous anesthesia was compared as measured by QoR-15 scores.

DESIGN

A prospective, double-blind, randomized controlled, non-inferiority trial.

SETTING

An operating room, a post-anesthesia care unit (PACU), and a hospital ward.

PATIENTS

Female patients (n = 140; 20-65 years) scheduled for open thyroidectomy were enrolled and randomly assigned to the remimazolam or propofol group.

INTERVENTIONS

The remimazolam group received continuous remimazolam infusions and effect-site target-controlled remifentanil infusions. The propofol group received effect-site target-controlled infusions of propofol and remifentanil.

MEASUREMENTS

The primary outcome was QoR-15 on postoperative day 1 (POD1). The mean difference between the groups was compared against a non-inferiority margin of -8. Secondary outcomes were QoR-15 on POD2, hemodynamic data, time to lose and recover consciousness, sedation score upon PACU admission, pain, and postoperative nausea and vomiting profiles at the PACU and ward. Group-time interaction effects in hemodynamic data and QoR-15 were analyzed using a linear mixed model.

MAIN RESULTS

The total QoR-15 score on POD1 in the remimazolam group was non-inferior to that in the propofol group (mean [SD] 111.2 [18.8] vs. 109.1 [18.9]; mean difference [95% CI] 2.1 [-4.2, 8.5]; p = 0.002 for non-inferiority). The QoR-15 score on POD2 was comparable between the groups, and no group-time interaction was observed. At the end of anesthesia, after extubation, and upon arrival at the PACU, mean arterial pressure was significantly higher in the remimazolam group. Remimazolam group was more sedated at the time of admission to PACU. Pain intensity and the requirement for analgesics were lower in the remimazolam group than in the propofol group.

CONCLUSIONS

Remimazolam-based total intravenous anesthesia provided a similar QoR to propofol. Remimazolam and propofol can be used interchangeably for general anesthesia in female patients undergoing thyroid surgery.

A case of suspected propofol infusion syndrome after abdominal aortic aneurysm surgery

Background

Propofol infusion syndrome (PRIS) is a rare but potentially lethal side effect during propofol administration.

Case presentation

The patient was scheduled for abdominal aortic aneurysm resection and reconstruction. Propofol used during sedation for ventilation after the surgery-induced rhabdomyolysis, heart failure, and renal failure. Discontinuation of propofol administration led to a dramatic improvement in the fatal symptoms, resulting in a diagnosis of PRIS.

Conclusions

We herein report a rare case of a PRIS during sedation in the intensive care unit after abdominal aortic aneurysm surgery. Physicians using propofol should therefore be aware of the potential risk of PRIS.

The Effects of Propofol Anesthesia on Lipid Profile and Some Biochemical Indices in Cats

The aim of the present study was to evaluate lipid profile (triglyceride, total cholesterol, HDL, LDL, and VLDL), pancreas (lipase and amylase), liver (AST, ALT, and ALP), blood urea nitrogen, creatinine, uric acid, sodium and potassium function indicators in cats undergoing two different durations of anesthesia with propofol. Ten adult female cats were randomly divided into two groups (n= 5) and anaesthetized with propofol 1% (induction: 8 mg/kg; infusion: 0.3 mg/kg/min) for either 45 or 90 minutes. Blood samples were collected at predetermined intervals up to 72 hours later. Comparison of the measured variables between treatments did not show significant differences. Triglyceride and cholesterol levels showed significant increase after induction of anesthesia (P < .05). The highest triglyceride and cholesterol values were recorded at 6 and 24 hours. HDL was lower while LDL and VLDL were higher at several time points after anesthesia (P < .05). Higher values of lipase, ALT and AST were detected after induction (P < .05). All the observed alterations were within normal ranges. In conclusion, propofol anesthesia was associated with some changes in lipid profile, as well as pancreatic and liver function indices, which should be considered in clinical situations. It seems that in the absence of pre- or co-existing disturbances, induction and maintenance of anesthesia with propofol did not carry additional risk to cats.

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.

An audit of propofol administration in the intensive care unit: Infusion pump-recorded versus electronically documented amounts

BACKGROUND

Although propofol is widely used for sedation in intensive care units around Australia, evaluation of bedside nursing practices of the administration of propofol have been limited. We investigated whether there was a discrepancy between the amount of propofol delivered by the infusion pump and that recorded electronically and consequently patient exposure to avoidable harms.

AIMS

The aim of this research was to compare the total amount of propofol administered to intensive care patients via a programmable infusion pump with that documented in the electronic medical record (EMR). Secondary objectives were to ascertain the percentage of 1) patients exposed to a propofol dose greater than recommended and 2) daily energy requirements administered as propofol infusion.

METHODS

This was a prospective, observational study of total propofol delivered to 50 patients in a 14-bed metropolitan, Australian intensive care unit. Infusion pump data and entries from the EMR were collated.

RESULTS

Propofol sedation was administered for a median 18 (interquartile range: 14-47) hours with median total propofol 3025 mg (interquartile range: 1840-7755 mg) by pump and 3250 mg (interquartile range: 1915-6960 mg) by EMR, i.e. 1.9 (interquartile range: 1.3-2.3) mg/kg/hour by pump (correlation coefficient = 0.99). The total bolus propofol documented in the EMR was a median 330 mg (interquartile range: -838 to -124) less than the pump amount. Nineteen (38%) patients had no EMR-documented propofol boluses yet had received at least one bolus via the pump. In two of 50 (4%) patients, the pump propofol infusion dose was above the recommended maximum safe dose of 4 mg/kg/h.

CONCLUSION

In this cohort of patients, the bolus administration of propofol was frequently not documented, potentially placing some patients at risk of drug-related toxicity. Further research to develop and implement strategies to improve the documentation of propofol administration is indicated.

Safety and efficacy of propofol anesthesia for pediatric target-controlled infusion in children below 3 years of age: a retrospective observational study

BACKGROUND

Although the requirement of propofol in children is increasing, propofol for induction and maintenance of anesthesia below 3 years old has not been approved in Korea. This study can provide a clinical evidence to increase the range of approval.

RESEARCH DESIGN AND METHODS

We reviewed the medical records of patients below 3 years of age who underwent surgery between September 2013 and December 2016. Safety was evaluated on the basis of vital signs, and laboratory findings and efficacy were evaluated on the basis of the bispectral index (BIS). Adverse events were examined.

RESULTS

A total of 109 patients anesthetized with propofol (propofol group) were compared with 109 patients with volatile anesthetics (volatile group) after propensity score matching. There was a difference in the proportion of patients showing decreased systolic pressure (P < 0.001) and heart rate (P = 0.03), but there was no difference in diastolic pressure (P = 0.238), mean arterial pressure (P = 0.175) during surgery. After surgery, there was no difference in all vital signs and the proportion patients who experienced adverse events of two groups.

CONCLUSIONS

Propofol anesthesia by target-controlled infusion was effective and didn't show serious propofol-related perioperative adverse events.

Sedation With a Combination of Dexmedetomidine and Midazolam for Pediatric Dental Surgery

Intravenous sedation (IVS) is commonly used to complete dental treatment for uncooperative pediatric patients. Propofol (PRO) is widely used for IVS because of its short context sensitive half-time and amnestic effect. However, administering PRO to patients who have a history of egg anaphylaxis is still somewhat controversial. The evidence that supports the potential risks for allergic reactions following PRO use in patients with egg allergies is limited with some anesthesiologists recommending against its use in these patients. Alternative drug regimens for procedural sedation in this population are therefore desirable. Dexmedetomidine (DEX), a selective α-2 agonist, has antianxiety and sedative properties and has been widely used not only for procedural sedation with mild inhibitory effects on respiration but also during minor surgeries for its analgesic effect. In this paper, we describe the successful administration of a combination of DEX and low-dose midazolam (MDZ) for sedation in an uncooperative pediatric patient. Both DEX and MDZ have been reported as safe and useful sedatives for dental treatment, and their combination may provide a helpful option for IVS of pediatric patients for whom PRO is not preferred.

A randomized crossover study of the effects of lidocaine on motor- and sensory-evoked potentials during spinal surgery

BACKGROUND CONTEXT

Lidocaine has emerged as a useful adjuvant anesthetic agent for cases requiring intraoperative monitoring of motor-evoked potentials (MEPs) and somatosensory-evoked potentials (SSEPs). A previous retrospective study suggested that lidocaine could be used as a component of propofol-based intravenous anesthesia without adversely affecting MEP or SSEP monitoring, but did not address the effect of the addition of lidocaine on the MEP and SSEP signals of individual patients.

PURPOSE

The purpose of this study was to examine the intrapatient effects of the addition of lidocaine to balanced anesthesia on MEPs and SSEPs during multilevel posterior spinal fusion.

STUDY DESIGN

This is a prospective, two-treatment, two-period crossover randomized controlled trial with a blinded primary outcome assessment.

PATIENT SAMPLE

Forty patients undergoing multilevel posterior spinal fusion were studied.

OUTCOME MEASURES

The primary outcome measures were MEP voltage thresholds and SSEP amplitudes. Secondary outcome measures included isoflurane concentrations and hemodynamic parameters.

METHODS

Each participant received two anesthetic treatments (propofol 50 mcg/kg/h and propofol 25 mcg/kg/h+lidocaine 1 mg/kg/h) along with isoflurane, ketamine, and diazepam. In this manner, each patient served as his or her own control. The order of administration of the two treatments was determined randomly.

RESULTS

There were no significant within-patient differences between MEP threshold voltages or SSEP amplitudes during the two anesthetic treatments.

CONCLUSIONS

Lidocaine may be used as a component of balanced anesthesia during multilevel spinal fusions without adversely affecting the monitoring of SSEPs or MEPs in individual patients.

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.

Severe heart failure and rhabdomyolysis associated with propofol infusion in a burn patient

The authors report a favorable outcome in an adult burn patient, who developed severe propofol-related infusion syndrome presenting with rhabdomyolysis, acute kidney injury, and right-sided heart failure after a low-dose propofol infusion. Other possible causes for late-onset rhabdomyolysis after burn trauma were ruled out by extensive differential diagnostics. The most distinctive abnormal finding was a Brugada-type ST-segment elevation, reported previously associating with imminent death. The patient survived because of cessation of propofol infusion and continuous renal replacement therapy. ECG recording is important in early detection of propofol-related infusion syndrome. ST elevations in the ECG should lead to the immediate discontinuation of propofol.

Propofol infusion associated metabolic acidosis in patients undergoing neurosurgical anesthesia: a retrospective study

Objective

Propofol and volatile anesthesia have been associated with metabolic acidosis induced by increased lactate. This study was designed to evaluate changes in pH, base excess (BE), and lactate in response to different anesthetic agents and to characterize propofol infusion-associated lactic acidosis.

Methods

The medical records of patients undergoing neurosurgical anesthesia between January 2005 and September 2012 were examined. Patients were divided into 2 groups : those who received propofol (total intravenous anesthesia, TIVA) and those who received sevoflurane (balanced inhalation anesthesia, BIA) anesthesia. Propensity analysis was performed (1 : 1 match, n=47), and the characteristics of the patients who developed severe acidosis were recorded.

Results

In the matched TIVA and BIA groups, the incidence of metabolic acidosis (11% vs. 13%, p=1) and base excess (p>0.05) were similar. All patients in the TIVA group who developed severe acidosis did so within 4 hours of the initiation of propofol infusion, and these patients improved when propofol was discontinued.

Conclusions

The incidence of metabolic acidosis was similar during neurosurgical anesthesia with propofol or sevoflurane. In addition, severe acidosis associated with propofol infusion appears to be reversible when propofol is discontinued.

Dexmedetomidine decreases the requirement of ketamine and propofol during burns debridement and dressings

Background and Aims:

Dexmedetomidine (Dex), a highly selective α₂-adrenoreceptor agonist, is used for sedation management in various clinical settings and shows anaesthetic-sparing effect. Our aim was to study the effects of Dex on requirements of propofol, ketamine, and intraoperative haemodynamic variations during burns debridement and dressing changes, and compare its effectiveness and safety with combination of ketamine and propofol.

Methods:

Sixty adult patients posted for elective debridement and dressing were included in the study. Thirty patients received Dex (intramuscular)(IM) 1 μg/kg, 1 h before shifting to the operation theatre while the other thirty did not. Anaesthesia was induced with propofol and ketamine followed by adjusted infusion to achieve a Ramsay Sedation Scale score (RSS) of six in all patients. Intraoperatively haemodynamic parameters were recorded at regular intervals of 5, 15, 30, 45, and 60 min. The mean data between the groups were compared by unpaired t test and medians by Mann-Whitney U test. Within group analysis was performed by using repeated measures ANOVA. P < 0.05 was considered significant.

Results:

The dose requirement of ketamine and propofol in Dex group was significantly lower when compared to control group (100.5 ± 17.58 mg vs. 231.5 ± 60.39 mg (P < 0.0001) and 127.7 ± 15.47 mg vs. 254 ± 59.22 mg (P < 0.0001) respectively). Additionally, recovery time was lower in the Dex group as compared to the control group, 9.57 ± 1.50 min vs. 11.53 ± 2.56 min (P = 0.0006). Haemodynamic variations were also significantly lower in the Dex group as compared to the control group.

Conclusion:

Dexmedetomidine (1 μg/kg IM) reduced the requirement of propofol and ketamine, with more stable intraoperative haemodynamics.

Propofol infusion syndrome resuscitation with extracorporeal life support: a case report and review of the literature

We report a case of propofol infusion syndrome (PRIS) in a young female treated for status epilepticus. In this case, PRIS rapidly evolved to full cardiovascular collapse despite aggressive supportive care in the intensive care unit, as well as prompt discontinuation of the offending agent. She progressed to refractory cardiac arrest requiring emergent initiation of venoarterial extracorporeal membrane oxygenation (ECMO) during cardiopulmonary resuscitation (CPR). She regained a perfusing rhythm after prolonged (>8 hours) asystole, was weaned off ECMO and eventually all life support, and was discharged to home. We also present a review of the available literature on the use of ECMO for PRIS.

Sedation for critically ill or injured adults in the intensive care unit: a shifting paradigm

As most critically ill or injured patients will require some degree of sedation, the goal of this paper was to comprehensively review the literature associated with use of sedative agents in the intensive care unit (ICU). The first and selected latter portions of this article present a narrative overview of the shifting paradigm in ICU sedation practices, indications for uninterrupted or prolonged ICU sedation, and the pharmacology of sedative agents. In the second portion, we conducted a structured, although not entirely systematic, review of the available evidence associated with use of alternative sedative agents in critically ill or injured adults. Data sources for this review were derived by searching OVID MEDLINE and PubMed from their first available date until May 2012 for relevant randomized controlled trials (RCTs), systematic reviews and/or meta-analyses and economic evaluations. Advances in the technology of mechanical ventilation have permitted clinicians to limit the use of sedation among the critically ill through daily sedative interruptions or other means. These practices have been reported to result in improved mortality, a decreased length of ICU and hospital stay and a lower risk of drug-associated delirium. However, in some cases, prolonged or uninterrupted sedation may still be indicated, such as when patients develop intracranial hypertension following traumatic brain injury. The pharmacokinetics of sedative agents have clinical importance and may be altered by critical illness or injury, co-morbid conditions and/or drug-drug interactions. Although use of validated sedation scales to monitor depth of sedation is likely to reduce adverse events, they have no utility for patients receiving neuromuscular receptor blocking agents. Depth of sedation monitoring devices such as the Bispectral Index (BIS©) also have limitations. Among existing RCTs, no sedative agent has been reported to improve the risk of mortality among the critically ill or injured. Moreover, although propofol may be associated with a shorter time to tracheal extubation and recovery from sedation than midazolam, the risk of hypertriglyceridaemia and hypotension is higher with propofol. Despite dexmedetomidine being linked with a lower risk of drug-associated delirium than alternative sedative agents, this drug increases risk of bradycardia and hypotension. Among adults with severe traumatic brain injury, there are insufficient data to suggest that any single sedative agent decreases the risk of subsequent poor neurological outcomes or mortality. The lack of examination of confounders, including the type of healthcare system in which the investigation was conducted, is a major limitation of existing pharmacoeconomic analyses, which likely limits generalizability of their results.

The effect of dexmedetomidine on the adjuvant propofol requirement and intraoperative hemodynamics during remifentanil-based anesthesia

BACKGROUND

The effects of dexmedetomidine on the propofol-sparing effect and intraoperative hemodynamics during remifentanil-based propofol-supplemented anesthesia have not been well investigated.

METHODS

Twenty patients undergoing breast surgery were randomly allocated to receive dexmedetomidine (group DEX) or placebo (group C). In the DEX group, dexmedetomidine was loaded (1 µg/kg) before anesthesia induction and was infused (0.6 µg/kg/h) during surgery. Anesthesia was induced with a target-controlled infusion (TCI) of propofol (effect site concentration, Ce; 3 µg/ml) and remifentanil (plasma concentration, Cp, 10 ng/ml). The Ce of TCI-propofol was adjusted to a bispectral index of 45-55, and Cp of TCI-remifentanil was fixed at 10 ng/ml in both groups. Mean arterial blood pressure (MAP) and heart rate (HR) were recorded at baseline (T-control), after the loading of study drugs (T-loading), 3 min after anesthesia induction (T-induction), tracheal intubation (T-trachea), incision (T-incision), 30 min after incision (T-incision30), and at tracheal extubation (T-extubation). MAP% and HR% (MAP and HR vs. T-control) were determined and the propofol infusion rate was calculated.

RESULTS

The propofol infusion rate was significantly lower in the DEX group than in group C (63.9 ± 16.2 vs. 96.4 ± 10.0 µg/kg/min, respectively; P < 0.001). The changes in MAP% at T-induction, T-trachea and T-incision in group DEX (-10.0 ± 3.9%, -9.4 ± 4.6% and -11.2 ± 6.3%, respectively) were significantly less than those in group C (-27.6 ± 13.9%, -21.7 ± 17.1%, and -25.1 ± 14.1%; P < 0.05, respectively).

CONCLUSIONS

Dexmedetomidine reduced the propofol requirement for remifentanil-based anesthesia while producing more stable intraoperative hemodynamics.

Total intravenous anesthesia (TIVA) in pediatric cardiac anesthesia

Although inhalational anesthesia with moderate- to high-dose opioid analgesia has been the mainstay of pediatric cardiac anesthesia, the availability of new short-acting drugs, new concepts in pharmacokinetic modeling and computer technology, and advances in surgery and perfusion have made total intravenous anesthesia (TIVA) an attractive option. In this article, we review some of the TIVA techniques used in pediatric cardiac anesthesia.

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.

Titrated propofol induction vs. continuous infusion in children undergoing magnetic resonance imaging

BACKGROUND

Propofol is the popular intravenous (i.v.) anaesthetic for paediatric sedation because of its rapid onset and recovery. We compared the efficacy and safety of a single dose and conventional infusion of propofol for sedation in children who underwent magnetic resonance imaging (MRI).

METHODS

This was a double-blind, randomized-controlled study. One hundred and sixty children were assigned to group I (single dose) or II (infusion). Sedation was induced with i.v. propofol 2 mg/kg, and supplemental doses of propofol 0.5 mg/kg were administered until adequate sedation was achieved. After the induction of sedation, we treated patients with a continuous infusion of normal saline at a rate of 0.3 ml/kg/h in group I and the same volume of propofol in group II. In case of inadequate sedation, additional propofol 0.5 mg/kg was administered and the infusion rate was increased by 0.05 ml/kg/h. Induction time, sedation time, recovery time, additional sedation and adverse events were recorded.

RESULTS

Recovery time was significantly shorter in group I compared with group II [0 (0-3) vs. 1 (0-3), respectively, P<0.001]. Group I (single dose) had significantly more patients with recovery time 0 compared with group II (infusion) (65/80 vs. 36/80, respectively, P<0.001). Induction and sedation times were not significantly different between groups. There was no significant difference in the frequency of additional sedation and adverse events between groups.

CONCLUSION

A single dose of propofol without a continuous infusion can provide appropriate sedation in children undergoing MRI for <30 min.

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.

Anesthesia and intraoperative neurophysiological monitoring in children

PURPOSE

Anesthesia for pediatric patients undergoing surgery where intraoperative neurophysiological monitoring (IONM) is performed is based on an understanding of the anesthetic influence on the neural pathways involved and the physiology that supplies nutrients to the neural systems. Anesthesia in pediatric patients may be different than in adults due to the specific anesthesia considerations in children, notably the propofol infusion syndrome (PRIS) and the need to monitor immature neural pathways. This review was done to determine if the anesthesia protocols used were different than those used in adults.

METHODS

After reviewing the implications of anesthetic action, a survey of pediatric anesthesia practitioners in 40 North American centers was conducted to determine the anesthesia protocols used in pediatric surgery with IONM and if these were specifically modified over concerns about PRIS.

RESULTS

Twenty-five centers responded with 35 different protocols used by practitioners. These protocols are similar to protocols used in adult patients. Although no centers specifically avoided propofol in all patients, several strategies were used to reduce the dosage, avoid its use in selected patients, or monitor for the onset of the syndrome.

CONCLUSION

Anesthesia for pediatric patients undergoing surgery where IONM is being performed is consistent with the practice and principles of anesthesia for adults. Although PRIS has not caused major alterations in most patients, concern has modified the practice of some anesthesiologists.

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.

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.

Propofol infusion syndrome in adult cardiac surgery

We report a case of rapid and progressive severe metabolic acidosis in the postoperative period after coronary artery bypass grafting. After exclusion of potential causes for this phenomenon, it was attributed to perioperative intravenous propofol infusion causing propofol infusion syndrome. We discontinued this intravenous agent resulting in a prompt and considerable improvement in the lactic acidosis and clinical condition in the subsequent 6 hours resulting in an uneventful recovery and hospital discharge.

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.

Toxicology in the critical care unit

Toxicologic conditions are encountered in critically ill patients due to intentional or unintentional misuse of or exposure to therapeutic or illicit drugs. Additionally, toxicities related to medical interventions may develop in hospitalized patients. This review focuses on recent developments in the field of critical care toxicology. Early interventions to decrease absorption or enhance elimination of toxins have limited value. Specific interventions to manage toxicities due to analgesics, sedative-hypnotics, antidepressants, antipsychotics, cardiovascular agents, alcohols, carbon monoxide, and cholinergic agents are reviewed. Hospital-acquired toxicities due to methemoglobinemia, propylene glycol, and propofol should be recognized and treated. The clinician is continually required to incorporate clinical judgment along with available scientific data and clinical evidence to determine the best therapy for toxicologic conditions.

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.

[Lactic acidosis associated with propofol during general anaesthesia for neurosurgery]

Propofol infusion syndrome (PRIS) is a new clinical entity reported in critically ill patients. Lactic acidosis, cardiac failure and rhabdomyolysis are the features. Lactic acidosis related to short-term propofol administration has been described during general anaesthesia. Lactic acidosis could be an early marker of PRIS. We report here a case of very early lactic acidosis in a 66-year-old-man receiving propofol during a neurosurgery. The outcome was good after discontinuation of propofol.

[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.