Halogenated inhalational anaesthetics

The role of the clinical pharmacist in the prevention of drug-induced acute kidney injury in the intensive care unit

WHAT IS KNOWN AND OBJECTIVE

Acute kidney injury (AKI) is a disorder that is commonly seen in patients in the intensive care unit (ICU) and has a detrimental impact on the patients' clinical prognosis. Although a variety of factors contribute to the development of AKI in patients, drug-induced AKI is a common occurrence in the ICU. With the widespread availability of clinical pharmacy services, the clinical pharmacist's consultation service to the healthcare team aids in the resolution of drug-related issues and the enhancement of therapeutic outcomes. The involvement of a clinical pharmacist in the ICU team is expected to minimize the incidence of drug-induced AKI and enhance therapeutic results. Therefore, the goal of our study was to demonstrate the impact of having a clinical pharmacist on the occurrence, stages, and treatment of AKI.

METHODS

The study included two patient groups: intervention (n = 75) (IG) and control (n = 75) (CG) groups. The clinical pharmacist has made recommendations to the ICU team regarding the treatment of IG patients on drug selection, drug administration routes, drug dose adjustment, drug-drug interactions, drug-food or nutritional solution interactions, drug side effect management, and drug incompatibility. No interventions were provided by the clinical pharmacist in the CG patients. The clinical pharmacist visited patients regularly and noted the laboratory findings and pharmacological treatments of patients in the study groups on the patient follow-up forms. The obtained data of IG and CG were compared and statistical methods were used to assess them.

RESULTS AND DISCUSSION

According to our findings, AKI was found to be more common in CG than in IG (p < 0.05). Stage 1 was shown to be the most common AKI stage in the patients (p > 0.05). The gap between the patients' highest Cr and basal sCr values was less in IG (p < 0.05). When the association between reasons for ICU admission and AKI was investigated, pulmonary edema and acute respiratory failure were found to have a significant and positive relationship with AKI (p < 0.05). Furthermore, it was shown that patients with diabetes and cancer comorbidities were the most vulnerable to developing AKI (p < 0.05). Antibiotics, anaesthetics, and cardiovascular system medication categories were found to have a significant and positive correlation with AKI in patients (p < 0.05). Also, it was revealed that the usage of vancomycin, colistin, ampicillin-sulbactam, clarithromycin, ceftriaxone, midazolam, and dexketoprofen caused AKI (p < 0.05).

WHAT IS NEW AND CONCLUSION

Our findings demonstrate that if a clinical pharmacist is included in the ICU team and provides consultation services to the ICU team regarding patient treatment by performing regular patient follow-up, the incidence of AKI in patients can be minimized and therapeutic outcomes can be improved.

Effects of Anesthesia on Postoperative Recurrence and Metastasis of Malignant Tumors

It is difficult to control the recurrence and metastasis of malignant tumors; furthermore, anesthesia is considered one of the main influencing factors. There has been increasing clinical attention on the effects of anesthetic drugs and methods on postoperative tumor growth and metastasis. We reviewed the effects of anesthesia on tumor recurrence and metastasis; specifically, the effects of anesthetic agents, anesthesia methods, and related factors during the perioperative period on the tumor growth and metastasis were analyzed. This study can provide reference standards for rational anesthesia formulations and cancer-related pain analgesia protocols for surgical procedures in patients with malignant tumors. Moreover, it contributes toward an experimental basis for the improvement and development of novel anesthetic agents and methods.

Comparative effect of desflurane and sevoflurane on liver function tests of patients with impaired hepatic function undergoing cholecystectomy: A randomized clinical study

Background and Aim:

Desflurane and sevoflurane are the most common volatile anesthetics used during laparoscopic and hepatic surgery. The objective of the study was to evaluate the effect of desflurane and sevoflurane in patients with elevated preoperative liver functions undergoing laparoscopic cholecystectomy.

Methods:

The study was a randomized study and included 162 patients classified randomly into two groups: Desflurane group: The patients received desflurane (end-tidal concentration 4%–6%) as an inhalational agent during the whole procedure. Sevoflurane group: The patients received sevoflurane (end-tidal concentration 2%–4%) as an inhalational agent during the whole procedure. The investigations included serum level of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT), and total bilirubin. The values were serially collected at the following timepoints; T0:at the preoperative period, T1:directly after surgery, T2:1^st postoperative day, T3:2^nd postoperative day, T4:3^rd postoperative day, T5:5^th postoperative day, T6:7^th postoperative day, and T7:10^th postoperative day. The statistics were described in terms of mean ± standard deviation, frequencies, and percentages.

Results:

The preoperative liver enzymes and total bilirubin were higher than the normal range in patients of the two groups. Postoperatively, there was a decrease in the AST and ALT with desflurane more than sevoflurane from T1 to T6(P < 0.05). The ALP, GGT, and bilirubin decreased in patients of the two groups, but the comparison was insignificant (P > 0.05).

Conclusion:

The desflurane is a safe inhalational volatile for maintenance of anesthesia in patients with impaired liver function undergoing laparoscopic cholecystectomy. It was associated with a decrease in the liver enzymes more than the sevoflurane.

Nonexperimental Xenobiotics: Unintended Consequences of Intentionally Administered Substances in Terrestrial Animal Models

Review of the use of nonexperimental xenobiotics in terrestrial animal models and the potential unintended consequences of these compounds, including drug-related side effects and adverse reactions.

Possible Pathways of Hepatotoxicity Caused by Chemical Agents

BACKGROUND

Liver injury induced by drugs has become a primary reason for acute liver disease and therefore posed a potential regulatory and clinical challenge over the past few decades and has gained much attention. It also remains the most common cause of failure of drugs during clinical trials. In 50% of all acute liver failure cases, drug-induced hepatoxicity is the primary factor and 5% of all hospital admissions.

METHODS

The various hepatotoxins used to induce hepatotoxicity in experimental animals include paracetamol, CCl4, isoniazid, thioacetamide, erythromycin, diclofenac, alcohol, etc. Among the various models used to induce hepatotoxicity in rats, every hepatotoxin causes toxicity by different mechanisms.

RESULTS

The drug-induced hepatotoxicity caused by paracetamol accounts for 39% of the cases and 13% hepatotoxicity is triggered by other hepatotoxic inducing agents.

CONCLUSION

Research carried out and the published papers revealed that hepatotoxins such as paracetamol and carbon- tetrachloride are widely used for experimental induction of hepatotoxicity in rats.

Comparison of the Postoperative Liver Function Between Total Intravenous Anesthesia and Inhalation Anesthesia in Patients with Preoperatively Elevated Liver Transaminase Levels: A Retrospective Cohort Study

Background

Anesthesia and surgery may deteriorate liver function in patients with elevated liver enzyme levels; therefore, in these patients, choosing anesthetics with less hepatotoxicity is important.

Methods

This retrospective study investigated the effect of total intravenous anesthesia (TIVA) versus inhalation anesthesia (INHA) on the postoperative liver function in patients with preoperatively elevated liver enzyme levels (aspartate transaminase [AST] or alanine transaminase [ALT] >40 U/L) who underwent non-hepatic surgery under general anesthesia. We compared the changes in enzyme levels within 24 hrs before and after surgery.

Results

In 730 patients (TIVA: n=138; INHA: n=592), the baseline characteristics were comparable, except for higher comorbidity rates in the TIVA group. The median anesthesia and operation times were significantly longer in the TIVA group because approximately 50% of the TIVA group (vs 19.7% of the INHA group) underwent neurosurgery, which had a relatively longer operation time than other surgeries. Intraoperative hypotensive events and vasopressor use were more frequent in the TIVA group. After 1:4 propensity score matching (TIVA: n=94; INHA: n=376), the baseline characteristics and surgical variables were comparable, except for longer anesthesia time. Before matching, postoperative AST and ALT changes were significantly lower in the TIVA group than in the INHA group. After matching, only the ALT change was significantly lower after TIVA than after INHA [median (interquartile range), -16.7 (-32 to -4) % vs -12.0 (-28.6-6.5) %, P=0.025].

Conclusion

TIVA may be safer for patients with preoperatively elevated liver transaminase levels.

Early, Subclinical Hematological Changes Associated with Occupational Exposure to High Levels of Nitrous Oxide

This study was undertaken to determine whether exposure of operating room personnel to inhalation anesthetics, nitrous oxide, isoflurane, and sevoflurane was associated with any hematological changes. This historical cohort study was performed in 2018 at a large public hospital in Shiraz, where 52 operating room personnel and 52 administrative staff were investigated. The blood sample was taken from all individuals for Complete Blood Count. Furthermore, demographic information was collected through questionnaires. Mean atmospheric concentrations of nitrous oxide, isoflurane, and sevoflurane, to which subjects were exposed, were 850.92, 2.40, and 0.18 ppm, respectively. The hematological parameters were within the normal range in both groups. However, the mean values of hemoglobin, hematocrit, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and red blood cell count in the exposed group were significantly lower than the control group. No significant differences were noted between the two groups as far as other hematological factors were concerned. These findings provide circumstantial evidence to further substantiate the notion that occupational exposure to inhalation anesthetics, under the exposure scenario explained in this study, is associated with subtle, subclinical, prepathologic hematological changes. Long-term consequence and ramifications of these effects require further investigation. The range of exposure levels to anesthetic gases in operating rooms.

Volatile Anesthetics and Immunity

Historically, volatile anesthetics have demonstrated interesting interactions with both the innate and adaptive immune systems. This review organizes these interactions into four phases: recognition, recruitment, response, and resolution. These phases represent a range of proinflammatory, inflammatory, and innate and adaptive immune regulatory responses. The interaction between volatile anesthetics and the immune system is discussed in the context of pathogenesis of infectious disease.

Anesthesia for Patients with Concomitant Cardiac and Renal Dysfunction

Renal disease and cardiovascular disease are commonly encountered in the same patient. The dynamic interactions between renal disease and cardiovascular disease have an impact on perioperative management. Renal failure is an independent risk factor for cardiovascular disease and the link between the two disease states remains to be fully elucidated.

Exposure to volatile anaesthetics is not followed by a massive induction of single-strand DNA breaks in operation theatre personnel

Volatile anaesthetics such as halothane, isoflurane and others were expected to produce a health challenge for operation room personnel because of prolonged occupational exposure to anaesthetic gases. To estimate a molecular background of adverse health effects, a cohort of 100 exposed individuals was studied by the single-cell gene electrophoresis (comet assay) test. DNA lesions in lymphocytes of the exposed group did not differ significantly compared with non-exposed blood donors. Then, the exposed group was further divided according to job position. A highest level of DNA lesions was established in nurses but without significant difference compared with other groups. When a time period of exposure was taken into account, a tendency to cumulate DNA lesions was found only in the group of anaesthesiologists. A very weak genotoxic effect established in this study is discussed in relation to DNA repair, adaptative response and potential self-elimination of sensitive individuals.

Retrospective cohort investigation of perioperative upper respiratory events in children undergoing general anesthesia via a supraglottic airway: A comparison of sevoflurane and desflurane

Desflurane is the most pungent of the currently used volatile anesthetics. We assessed whether the incidence of perioperative upper respiratory events in children undergoing general anesthesia via a supraglottic airway is higher with desflurane than with sevoflurane as maintenance anesthetic.We retrospectively reviewed and analyzed the electronic medical records of consecutive children 1 to 15 years of age who underwent general anesthesia via a supraglottic airway at Seoul National University Bundang Hospital between June 2013 and June 2015. The patients were assigned to the sevoflurane or desflurane group according to the anesthetic used. The characteristics of the patients were compared. The primary outcome variable was the incidence of upper respiratory events.The incidence of upper respiratory events in the 3439 evaluated patients was 0.43% (12/2777) in the sevoflurane group and 0.30% (2/662) in the desflurane group (P = 0.75; odds ratio = 0.69 [95% confidence interval = 0.16-3.13]). The difference between the 2 groups was not significant.Compared with sevoflurane, desflurane does not increase the risk of perioperative upper respiratory events in children receiving general anesthesia via a supraglottic airway.

Isoflurane Is More Deleterious to Developing Brain Than Desflurane: The Role of the Akt/GSK3β Signaling Pathway

Demand is increasing for safer inhalational anesthetics for use in pediatric anesthesia. In this regard, researchers have debated whether isoflurane is more toxic to the developing brain than desflurane. In the present study, we compared the effects of postnatal exposure to isoflurane with those of desflurane on long-term cognitive performance and investigated the role of the Akt/GSK3β signaling pathway. Postnatal day 6 (P6) mice were exposed to either isoflurane or desflurane, after which the phosphorylation levels of Akt/GSK3β and learning and memory were assessed at P8 or P31. The phosphorylation levels of Akt/GSK3β and learning and memory were examined after intervention with lithium. We found that isoflurane, but not desflurane, impaired spatial learning and memory at P31. Accompanied by behavioral change, only isoflurane decreased p-Akt (ser473) and p-GSK3β (ser9) expressions, which led to GSK3β overactivation. Lithium prevented GSK3β overactivation and alleviated isoflurane-induced cognitive deficits. These results suggest that isoflurane is more likely to induce developmental neurotoxicity than desflurane in context of multiple exposures and that the Akt/GSK3β signaling pathway partly participates in this process. GSK3β inhibition might be an effective way to protect against developmental neurotoxicity.

Intraoperative factors associated with delayed recovery of liver function after hepatectomy: analysis of 1969 living donors

BACKGROUND

The safety of healthy living donors who are undergoing hepatic resection is a primary concern. We aimed to identify intraoperative anaesthetic and surgical factors associated with delayed recovery of liver function after hepatectomy in living donors.

METHODS

We retrospectively analysed 1969 living donors who underwent hepatectomy for living donor liver transplantation. Delayed recovery of hepatic function was defined by increases in international normalised ratio of prothrombin time and concomitant hyperbilirubinaemia on or after post-operative day 5. Univariate and multivariate logistic regression analyses were performed to determine the factors associated with delayed recovery of hepatic function after living donor hepatectomy.

RESULTS

Delayed recovery of liver function after donor hepatectomy was observed in 213 (10.8%) donors. Univariate logistic regression analysis showed that sevoflurane anaesthesia, synthetic colloid, donor age, body mass index, fatty change and remnant liver volume were significant factors for prediction of delayed recovery of hepatic function. Multivariate logistic regression analysis showed that independent factors significantly associated with delayed recovery of liver function after donor hepatectomy were sevoflurane anaesthesia (odds ratio = 3.514, P < 0.001), synthetic colloid (odds ratio = 1.045, P = 0.033), donor age (odds ratio = 0.970, P = 0.003), female gender (odds ratio = 1.512, P = 0.014) and remnant liver volume (odds ratio = 0.963, P < 0.001).

CONCLUSIONS

Anaesthesia with sevoflurane was an independent factor in predicting delayed recovery of hepatic function after donor hepatectomy. Although synthetic colloid may be associated with delayed recovery of hepatic function after donor hepatectomy, further study is required. These results can provide useful information on perioperative management of living liver donors.

Effects of propofol versus isoflurane on liver function after open thoracotomy

Background

Anesthetic agents and type of surgery may contribute to postoperative hepatic injury. Inhalational anesthetics have been associated with hepatic dysfunction after surgery, however, propofol is expected to have a lower potential for postoperative liver injury. This prospective double-blind randomized clinical study was planned to determine whether postoperative liver function differs after anesthesia with isoflurane and total intravenous anesthesia with propofol in patients undergoing a posterolateral thoracotomy.

Methods

Eighty-eight patients in American Society of Anesthesiologists physical status 1 or 2, aged 16–60 years, and scheduled for an elective posterolateral thoracotomy, were randomly assigned to an anesthetic protocol: propofol ( n = 44) or isoflurane ( n = 44). Induction of anesthesia was similar in both groups. Serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, total bilirubin, and γ-glutamyltransferase were measured before induction of anesthesia and on the first and third days after either propofol or isoflurane anesthesia.

Results

Mild changes in postoperative serum levels of liver enzymes were significant within each group but the differences between groups were not significant.

Conclusions

Propofol and isoflurane anesthesia have a comparable minor effect on liver function after an elective posterolateral thoracotomy.

Hepatotoxicity of halogenated inhalational anesthetics

Context:

Halogenated inhalational anesthetics are currently the most common drugs used for the induction and maintenance of general anesthesia. Postoperative hepatic injury has been reported after exposure to these agents. Based on much evidence, mechanism of liver toxicity is more likely to be immunoallergic. The objective of this review study was to assess available studies on hepatotoxicity of these anesthetics.

Evidence Acquisition:

We searched PubMed, Google Scholar, Scopus, Index Copernicus, EBSCO and the Cochrane Database using the following keywords: “inhalational Anesthetics” and “liver injury”; “inhalational anesthetics” and “hepatotoxicity”; “volatile anesthetics” and “liver injury”; “volatile anesthetics” and hepatotoxicity for the period of 1966 to 2013. Fifty two studies were included in this work.

Results:

All halogenated inhalational anesthetics are associated with liver injury. Halothane, enflurane, isoflurane and desflurane are metabolized through the metabolic pathway involving cytochrome P-450 2E1 (CYP2E1) and produce trifluoroacetylated components; some of which may be immunogenic. The severity of hepatotoxicity is associated with the degree by which they undergo hepatic metabolism by this cytochrome. However, liver toxicity is highly unlikely from sevoflurane as is not metabolized to trifluoroacetyl compounds.

Conclusions:

Hepatotoxicity of halogenated inhalational anesthetics has been well documented in available literature. Halothane-induced liver injury was extensively acknowledged; however, the next generation halogenated anesthetics have different molecular structures and associated with less hepatotoxicity. Although anesthesia-induced hepatitis is not a common occurrence, we must consider the association between this disorder and the use of halogenated anesthetics.

Sevoflurane therapy for life-threatening acute severe asthma: a case report

INTRODUCTION

Acute severe asthma is a life-threatening form of bronchial constriction in which the progressively worsening airway obstruction is unresponsive to the usual appropriate bronchodilator therapy. Pathophysiological changes restrict airflow, which leads to premature closure of the airway on expiration, impaired gas exchange, and dynamic hyperinflation ("air-trapping"). Additionally, patients suffering from asthma for a prolonged period of time usually have serious comorbidities. These conditions constitute a challenge during the treatment of this disease. Therapeutic interventions are designed to reduce airway resistance and improve respiratory status. To achieve therapeutic goals, appropriate bronchodilator treatment is indispensable, and mechanical ventilation under adequate sedation may also be required. The volatile anesthetic agent, sevoflurane, meets both criteria; therefore, its use can be beneficial and should be considered.

CASE PRESENTATION

A 67-yr-old Caucasian male presented with acute life-threatening asthma provoked by an assumed upper airway infection and non-steroidal anti-inflammatory drug antipyretics, complicated by chronic atrial fibrillation and hemodynamic instability. Due to frequent premature ventricular contractions, conventional treatment was considered unsafe and discontinued, and sevoflurane inhalation was initiated via the AnaConDa (Anaesthetic Conserving Device). Symptoms of life-threatening bronchospasm resolved, and the patient's respiratory status improved within hours. Adequate sedation was also achieved without any hemodynamic adverse effects.

CONCLUSION

The volatile anesthetic agent, sevoflurane, is used widely in anesthesia practice. Its utility for treatment of refractory bronchospasm has been appreciated for years; however, its administration was difficult within the environment of the intensive care unit due to the need for an anesthesia machine and a scavenging system. The introduction of the AnaConDa eliminates these obstacles and makes the use of sevoflurane safe and simple. Our case report reveals the potential of sevoflurane as a "two-in-one" (bronchodilator and sedative) drug to treat a severe acute asthma attack.

Drug-induced hepatotoxicity: incidence of abnormal liver function tests consistent with volatile anaesthetic hepatitis in trauma patients

BACKGROUND & AIMS

Volatile anaesthetic drug-induced liver injury can range from asymptomatic alanine transaminase elevations to fatal hepatic necrosis. There is very limited research regarding hepatotoxicity of modern volatile anaesthetic agents. The aim of this study was to determine how common liver injury consistent with volatile anaesthetic hepatitis is, following exposure to isoflurane, desflurane and sevoflurane; and to propose risk factors for its development.

METHODS

Following ethics approval, we conducted a retrospective audit of adult trauma patients with abnormal liver biochemistry following volatile anaesthesia during January 1 to December 31, 2009. The data collected included patient demographics, volatile anaesthetic administration, concurrent medication, perioperative liver biochemistry results and comorbidities. The Council for International Organisations of Medical Sciences/Roussel Uclaf Causality Assessment Method scoring system was used to group cases according to the likelihood of volatile anaesthetic being the causative agent of drug-induced hepatotoxicity.

RESULTS

Forty-seven (3%) of 1556 patients had abnormal post-operative liver biochemistry potentially attributable to volatile anaesthetic. Of the 47, 12 patients (26%) had peak alanine transaminase levels greater than 200 U/L. No significant predictors of volatile anaesthetic drug-induced liver injury following isoflurane, desflurane or sevoflurane anaesthesia could be identified.

CONCLUSION

Volatile anaesthetic drug-induced liver injury in adult trauma patients may be significantly more common than previously noted. This study suggests that about a quarter of patients with volatile anaesthetic drug-induced liver injury develop significant liver injury. Further prospective studies are required to define risk factors and clinical outcomes.

The effects of N-acetylcysteine on hepatic function during isoflurane anaesthesia for laparoscopic surgery patients

Introduction:

Although most general anaesthesia procedures are performed without any complications, volatile agents may have adverse effects on various living systems. This study aims to compare the antioxidant effects of isoflurane and N-acetylcysteine (NAC) on liver function.

Methods:

Forty-one patients in the ASA I-II risk groups, who were scheduled to undergo gynaecologic laparoscopy, were randomly divided into two groups: The placebo (group P, n=21) and the NAC group (group N, n=20). In both groups, anaesthesia was maintained with 1–2% isoflurane in 50% Oxygen–50% N₂O at 6 l/min, also administered by inhalation. Venous blood samples were obtained before anaesthesia induction, and then in the postoperative 1^st hour and at the 24^th hour. The samples were centrifuged and serum levels of glutathione S-transferase (GST), malondialdehyde (MDA), aspartate amino transferase (AST), alanine amino transferase (ALT), lactate dehydrogenase (LDH), gamma glutamyltranspeptidase (GGT), prothrombin time (PT), activated partial thromboplastin time (aPTT) and international normalised ratio were determined.

Results:

GST levels were significantly higher in group N than in group P in the postoperative 1^st hour. Postoperative values of GST in the two groups were higher when compared to preoperative values (P<0.05). When postoperative levels were compared with preoperative levels, the postoperative MDA levels of group N were significantly higher (P<0.05). Levels of AST, ALT, GGT and LDH in both groups revealed significant decreases at the postoperative 1^st hour and postoperative 24^th hour compared to preoperative values (P<0.05, P<0.001). PT values were significantly higher in both groups in the postoperative 1^st hour and 24^th hour (P<0.05, P<0.001), although there were no differences in aPTT levels.

Conclusion:

Our results showed that liver functions were well preserved with administration of NAC during anaesthesia with isoflurane. Isoflurane with NAC has lesser effect on liver function tests compared to isoflurane alone.

Impact of obesity on drug metabolism and elimination in adults and children

The prevalence of obesity in adults and children is rapidly increasing across the world. Several general (patho)physiological alterations associated with obesity have been described, but the specific impact of these alterations on drug metabolism and elimination and its consequences for drug dosing remains largely unknown. In order to broaden our knowledge of this area, we have reviewed and summarized clinical studies that reported clearance values of drugs in both obese and non-obese patients. Studies were classified according to their most important metabolic or elimination pathway. This resulted in a structured review of the impact of obesity on metabolic and elimination processes, including phase I metabolism, phase II metabolism, liver blood flow, glomerular filtration and tubular processes. This literature study shows that the influence of obesity on drug metabolism and elimination greatly differs per specific metabolic or elimination pathway. Clearance of cytochrome P450 (CYP) 3A4 substrates is lower in obese as compared with non-obese patients. In contrast, clearance of drugs primarily metabolized by uridine diphosphate glucuronosyltransferase (UGT), glomerular filtration and/or tubular-mediated mechanisms, xanthine oxidase, N-acetyltransferase or CYP2E1 appears higher in obese versus non-obese patients. Additionally, in obese patients, trends indicating higher clearance values were seen for drugs metabolized via CYP1A2, CYP2C9, CYP2C19 and CYP2D6, while studies on high-extraction-ratio drugs showed somewhat inconclusive results. Very limited information is available in obese children, which prevents a direct comparison between data obtained in obese children and obese adults. Future clinical studies, especially in children, adolescents and morbidly obese individuals, are needed to extend our knowledge in this clinically important area of adult and paediatric clinical pharmacology.

Desflurane: a clinical update of a third-generation inhaled anaesthetic

Available volatile anaesthetics are safe and efficacious; however, their varying pharmacology provides small but potentially clinically important differences. Desflurane is one of the third-generation inhaled anaesthetics. It is the halogenated inhaled anaesthetic with the lowest blood and tissue solubilities, which promotes its rapid equilibration and its rapid elimination following cessation of administration at the end of anaesthesia. The low fat solubility of desflurane provides pharmacological benefits, especially in overweight patients and in longer procedures by reducing slow compartment accumulation. A decade of clinical use has provided evidence for desflurane's safe and efficacious use as a general anaesthetic. Its benefits include rapid and predictable emergence, and early recovery. In addition, the use of desflurane promotes early and predictable extubation, and the ability to rapidly transfer patients from the operating theatre to the recovery area, which has a positive impact on patient turnover. Desflurane also increases the likelihood of patients, including obese patients, recovering their protective airway reflexes and awakening to a degree sufficient to minimise the stay in the high dependency recovery area. The potential impact of the rapid early recovery from desflurane anaesthesia on intermediate and late recovery and resumption of activities of daily living requires further study.

Fulminant hepatic failure after repeated exposure to isoflurane

Inhalational agents are used routinely for maintenance of anaesthesia. Post anaesthesia hepatic failure has been documented following exposure to halothane. However, there are very few reports of such complications following isoflurane anaesthesia. A 6-year-old child developed fulminant hepatic failure 2 days following craniotomy under general anaesthesia. There was no evidence of viral, autoimmune, or metabolic causes of hepatitis. No other medications known to cause hepatitis, except low dose paracetamol, were administered. The clinical and histological picture of our case is similar to that of halothane hepatitis, which has a significant mortality rate. We report this as a possible fulminant hepatic failure resulting from exposure to isoflurane anaesthesia.

The effects of desflurane and sevoflurane on hepatic and renal functions after right hepatectomy in living donors*

We compared postoperative hepatic and renal functions between the two inhalational anesthetics, desflurane and sevoflurane in living donors undergoing right hepatectomy. Seventy-four adult donors were randomly allocated into Des group (n = 37) and sevo group (n = 37). Before the induction of anesthesia, morphine sulfate 400 microg was injected intrathecally. Anesthesia was maintained with one minimum alveolar concentration (MAC) of deflurane or sevoflurane plus continuous intravenous remifentanil. Liver and renal function tests were performed and analysed at preoperative period, immediately after operation, and on 1st, 2nd, 3rd, 5th, 7th, and 30th postoperative days (PODs). Aspartate aminotransferase (AST) showed significant elevations from the day of surgery to POD 3 and alanine aminotransferase (ALT) was significantly elevated on POD 1 and POD 3 in the sevo group. Albumin level was significantly lower on POD 2 in the sevo group. Creatinine was significantly higher on POD 3 and POD 30 and estimated glomerular filtration ratio was significantly lower on POD 3 and POD 30 in the sevo group. No patient developed hepatic or renal failures. The results of our study showed better postoperative hepatic and renal function test with desflurane than sevoflurane at equivalent dose of 1 MAC in living donors undergoing right hepatectomy, but further study is required to evaluate clinical importance.

Sevoflurane inside and outside the operating room

BACKGROUND

Sevoflurane is often presented as a near-perfect anaesthetic. After 10 years in the operating room, new uses are emerging outside.

OBJECTIVE

To remind readers of the principal characteristics of sevoflurane, to affirm its usefulness for day-case anaesthesia and to consider the recent new uses.

METHODS

The discussion of the physical properties, pharmacokinetics, metabolism, mechanisms of action and clinical effects is based on classic, essential papers. Recent literature concerning emerging utilizations of sevoflurane was analysed.

RESULTS

Sevoflurane presents many benefits with minimum inconvenience. It allows rapid inhalation induction, maintenance and rapid recovery. It has little toxicity and its haemodynamic and respiratory depressive effects are moderate and well tolerated. It is already widely use for sedation for magnetic resonance imaging in children. Its use in paediatric or adult intensive care could improve the management of pain and sedation.

Acute renal dysfunction in liver diseases

Renal dysfunction is common in liver diseases, either as part of multiorgan involvement in acute illness or secondary to advanced liver disease. The presence of renal impairment in both groups is a poor prognostic indicator. Renal failure is often multifactorial and can present as pre-renal or intrinsic renal dysfunction. Obstructive or post renal dysfunction only rarely complicates liver disease. Hepatorenal syndrome (HRS) is a unique form of renal failure associated with advanced liver disease or cirrhosis, and is characterized by functional renal impairment without significant changes in renal histology. Irrespective of the type of renal failure, renal hypoperfusion is the central pathogenetic mechanism, due either to reduced perfusion pressure or increased renal vascular resistance. Volume expansion, avoidance of precipitating factors and treatment of underlying liver disease constitute the mainstay of therapy to prevent and reverse renal impairment. Splanchnic vasoconstrictor agents, such as terlipressin, along with volume expansion, and early placement of transjugular intrahepatic portosystemic shunt (TIPS) may be effective in improving renal function in HRS. Continuous renal replacement therapy (CRRT) and molecular absorbent recirculating system (MARS) in selected patients may be life saving while awaiting liver transplantation.

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.

Formation and toxicity of anesthetic degradation products

Toxic degradation products are formed from a range of old and modern anesthetic agents. The common element in the formation of degradation products is the reaction of the anesthetic agent with the bases in the carbon dioxide absorbents in the anesthesia circuit. This reaction results in the conversion of trichloroethylene to dichloroacetylene, halothane to 2-bromo-2-chloro-1,1-difluoroethylene, sevoflurane to 2-(fluoromethoxy)-1,1,3,3,3-pentafluoro-1-propene (Compound A), and desflurane, isoflurane, and enflurane to carbon monoxide. Dichloroacetylene, 2-bromo-2-chloro-1,1-difluoroethylene, and Compound A form glutathione S-conjugates that undergo hydrolysis to cysteine S-conjugates and bioactivation of the cysteine S-conjugates by renal cysteine conjugate beta-lyase to give nephrotoxic metabolites. The elucidation of the mechanisms of formation and bioactivation of degradation products has allowed for the safe use of anesthetics that may undergo degradation in the anesthesia circuit.

Acute toxic renal failure

Acute renal failure (ARF) is a common problem in intensive care medicine. Even modest degrees of ARF not requiring dialysis treatment increase the risk of death approximately fivefold. Despite the widespread appreciation of the role of nephrotoxic drugs in their contribution to ARF, these drugs continue to have an ongoing aetiological role. Potentially nephrotoxic drugs include non-steroidal anti-inflammatory drugs, radiocontrast agents, antimicrobial and anaesthetic agents. Endogenous compounds such as myoglobin and haemoglobin may furthermore cause toxic nephropathy. Tubular injury initiated by toxins often results from a combination of acute renal vasoconstriction and direct cellular toxicity due to intracellular accumulation of the toxin, or, alternatively, may be mediated immunologically in case of interstitial nephritis. Patients with reduced renal functional reserve, cardiovascular co-morbidity, diabetes mellitus, and advanced age are at increased risk. Awareness of the range of toxins on the one hand and simple measures such as adequate pre-hydration of the patient and drug monitoring on the other hand may be sufficient to avoid drug-induced ARF or minimize its clinical severity in susceptible patients.