Comparison of the effects of isoflurane and propofol on hepatic glutathione-S-transferase concentrations during and after prolonged anaesthesia

Evaluation of the effects of two anaesthetic protocols on oxidative status and DNA damage in red-eared sliders (Trachemys scripta elegans) undergoing endoscopic coeliotomy

The aim of this study was to assess how red-eared sliders (Trachemys scripta elegans) respond to anaesthesia itself and coelioscopy. For that purpose, the turtles were anaesthetised with ketamine-medetomidine or propofol, and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) and the level of malondialdehyde (MDA) were determined by spectrophotometry. The possible genotoxic effects of the anaesthetic agents were estimated by comet assay. A total of 24 turtles were included in this study. The animals were divided into four groups according to the anaesthetic protocol and according to whether endoscopy would be performed. Significantly decreased activities of CAT were found only in the propofol group and in turtles undergoing coelioscopy. Both anaesthetic protocols induced significantly increased MDA levels, while no differences were observed after the intervention. A significant increase in GST activity was detected in turtles after both anaesthetic protocols, but after coelioscopy significant changes in GST activity were found only in the propofol group. However, no differences in SOD activity and no DNA damages were detected in either group. These findings suggest that ketamine-medetomidine may be more suitable anaesthetic agents in red-eared sliders than propofol.

Intravenous versus inhalational maintenance of anaesthesia for postoperative cognitive outcomes in elderly people undergoing non-cardiac surgery

BACKGROUND

The use of anaesthetics in the elderly surgical population (more than 60 years of age) is increasing. Postoperative delirium, an acute condition characterized by reduced awareness of the environment and a disturbance in attention, typically occurs between 24 and 72 hours after surgery and can affect up to 60% of elderly surgical patients. Postoperative cognitive dysfunction (POCD) is a new-onset of cognitive impairment which may persist for weeks or months after surgery.Traditionally, surgical anaesthesia has been maintained with inhalational agents. End-tidal concentrations require adjustment to balance the risks of accidental awareness and excessive dosing in elderly people. As an alternative, propofol-based total intravenous anaesthesia (TIVA) offers a more rapid recovery and reduces postoperative nausea and vomiting. Using TIVA with a target controlled infusion (TCI) allows plasma and effect-site concentrations to be calculated using an algorithm based on age, gender, weight and height of the patient.TIVA is a viable alternative to inhalational maintenance agents for surgical anaesthesia in elderly people. However, in terms of postoperative cognitive outcomes, the optimal technique is unknown.

OBJECTIVES

To compare maintenance of general anaesthesia for elderly people undergoing non-cardiac surgery using propofol-based TIVA or inhalational anaesthesia on postoperative cognitive function, mortality, risk of hypotension, length of stay in the postanaesthesia care unit (PACU), and hospital stay.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 11), MEDLINE (1946 to November 2017), Embase (1974 to November 2017), PsycINFO (1887 to November 2017). We searched clinical trials registers for ongoing studies, and conducted backward and forward citation searching of relevant articles.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) with participants over 60 years of age scheduled for non-cardiac surgery under general anaesthesia. We planned to also include quasi-randomized trials. We compared maintenance of anaesthesia with propofol-based TIVA versus inhalational maintenance of anaesthesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data, assessed risk of bias, and synthesized findings.

MAIN RESULTS

We included 28 RCTs with 4507 randomized participants undergoing different types of surgery (predominantly cardiovascular, laparoscopic, abdominal, orthopaedic and ophthalmic procedures). We found no quasi-randomized trials. Four studies are awaiting classification because we had insufficient information to assess eligibility.All studies compared maintenance with propofol-based TIVA versus inhalational maintenance of anaesthesia. Six studies were multi-arm and included additional TIVA groups, additional inhalational maintenance or both. Inhalational maintenance agents included sevoflurane (19 studies), isoflurane (eight studies), and desflurane (three studies), and was not specified in one study (reported as an abstract). Some studies also reported use of epidural analgesia/anaesthesia, fentanyl and remifentanil.We found insufficient reporting of randomization methods in many studies and all studies were at high risk of performance bias because it was not feasible to blind anaesthetists to study groups. Thirteen studies described blinding of outcome assessors. Three studies had a high of risk of attrition bias, and we noted differences in the use of analgesics between groups in six studies, and differences in baseline characteristics in five studies. Few studies reported clinical trials registration, which prevented assessment of risk of selective reporting bias.We found no evidence of a difference in incidences of postoperative delirium according to type of anaesthetic maintenance agents (odds ratio (OR) 0.59, 95% confidence interval (CI) 0.15 to 2.26; 321 participants; five studies; very low-certainty evidence); we noted during sensitivity analysis that using different time points in one study may influence direction of this result. Thirteen studies (3215 participants) reported POCD, and of these, six studies reported data that could not be pooled; we noted no difference in scores of POCD in four of these and in one study, data were at a time point incomparable to other studies. We excluded one large study from meta-analysis because study investigators had used non-standard anaesthetic management and this study was not methodologically comparable to other studies. We combined data for seven studies and found low-certainty evidence that TIVA may reduce POCD (OR 0.52, 95% CI 0.31 to 0.87; 869 participants).We found no evidence of a difference in mortality at 30 days (OR 1.21, 95% CI 0.33 to 4.45; 271 participants; three studies; very low-certainty evidence). Twelve studies reported intraoperative hypotension. We did not perform meta-analysis for 11 studies for this outcome. We noted visual inconsistencies in these data, which may be explained by possible variation in clinical management and medication used to manage hypotension in each study (downgraded to low-certainty evidence); one study reported data in a format that could not be combined and we noted little or no difference between groups in intraoperative hypotension for this study. Eight studies reported length of stay in the PACU, and we did not perform meta-analysis for seven studies. We noted visual inconsistencies in these data, which may be explained by possible differences in definition of time points for this outcome (downgraded to very low-certainty evidence); data were unclearly reported in one study. We found no evidence of a difference in length of hospital stay according to type of anaesthetic maintenance agent (mean difference (MD) 0 days, 95% CI -1.32 to 1.32; 175 participants; four studies; very low-certainty evidence).We used the GRADE approach to downgrade the certainty of the evidence for each outcome. Reasons for downgrading included: study limitations, because some included studies insufficiently reported randomization methods, had high attrition bias, or high risk of selective reporting bias; imprecision, because we found few studies; inconsistency, because we noted heterogeneity across studies.

AUTHORS' CONCLUSIONS

We are uncertain whether maintenance with propofol-based TIVA or with inhalational agents affect incidences of postoperative delirium, mortality, or length of hospital stay because certainty of the evidence was very low. We found low-certainty evidence that maintenance with propofol-based TIVA may reduce POCD. We were unable to perform meta-analysis for intraoperative hypotension or length of stay in the PACU because of heterogeneity between studies. We identified 11 ongoing studies from clinical trials register searches; inclusion of these studies in future review updates may provide more certainty for the review outcomes.

Glutathione S-transferase as a toxicity indicator in general anesthesia: genetics and biochemical function

General anesthesia may lead in patients to unexpected and adverse reactions including toxicity. Glutathione S-transferases (GSTs) are enzymes responsible for the detoxification process of anesthetic agents. Plasma and urine GST measurements are used in multiple studies as a hepatocellular integrity or renal injury indicator. The importance of GST enzyme measurements in monitoring the hepatotoxic and nephrotoxic effect in anesthetized patients is presented. The biochemical function and specific properties of GST render it a prognostic biomarker. This review demonstrates that GST can be valuable and promising toxicity indicator in patients undergoing general anesthesia.

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.

Comparison of plasma alpha glutathione S-transferase concentrations during and after low-flow sevoflurane or isoflurane anaesthesia

BACKGROUND

We evaluated the effect of low-flow sevoflurane anaesthesia, in which compound A is generated, and isoflurane anaesthesia, in which compound A is not generated (n=13 in each group), on hepatocellular integrity using alpha glutathione S-transferase (GST). Alpha GST is a more sensitive and specific marker of hepatocellular damage than is aminotransferase activity and correlates better with hepatic histology.

METHODS

Sevoflurane or isoflurane were delivered without nitrous oxide with a fresh gas flow of 1 l/min. Concentrations of compound A in the circuit were measured hourly, and plasma alpha GST concentrations were measured perioperatively.

RESULTS

Mean duration of anaesthesia was 338+/-92 min in the sevoflurane group and 320+/-63 min in the isoflurane group. Mean compound A concentration in the sevoflurane group was 28.6+/-9.0 ppm. There was no significant difference in alpha GST concentrations between the sevoflurane and isoflurane groups during or after anaesthesia.

CONCLUSION

These results indicate that low-flow sevoflurane and isoflurane anaesthesia have the same effect on hepatic function, as assessed by plasma alpha GST concentrations.

Disturbance of hepatocellular integrity associated with propofol anaesthesia in surgical patients

Propofol anaesthesia has not been associated with any hepatic consequences. We used glutathione transferase Alpha (GSTA), a very sensitive indicator of hepatocellular integrity, to evaluate the effect of propofol on the liver. Total intravenous anaesthesia was induced and maintained with propofol without any supplements in 30 female patients undergoing breast surgery. Ten healthy female volunteers given the lipid vehicle of propofol served as controls. Serum GSTA concentration was measured with a sensitive time-resolved immunofluorometric assay. Total intravenous propofol anaesthesia was stable and postoperative nausea negligible. A significant increase in GSTA from 3.1 micrograms.l-1 (mean baseline) to 10.0 micrograms.l-1 (mean peak) was noted after propofol infusion, indicating subclinical disturbance in hepatocellular integrity. No change in aminotransferases and no clinical signs of hepatotoxicity were observed. A small increase in GSTA from 2.4 micrograms.l-1 (mean baseline) to 4.1 micrograms.l-1 (mean peak) was observed during lipid infusion. We detected a subclinical disturbance in hepatocellular integrity after propofol anaesthesia for breast surgery. The mechanisms of hepatocellular impairment are not clear but the lipid vehicle of propofol alone does not explain it.