Effects of sevoflurane anesthesia on plasma inorganic fluoride concentrations during and after cardiac surgery

Case report: proximal tubule impairment following volatile anesthetic exposure

The safety of contemporary volatile anesthetic agents with respect to kidney function is well established, and growing evidence suggests that volatile anesthetics even protect against ischemic nephropathy. However, studies examining effects of volatile anesthetics on kidney function frequently demonstrate transient proteinuria and glycosuria following exposure to these agents, although the cause of these findings has not been thoroughly examined. We describe the case of a patient who underwent a neurosurgical procedure, then experienced glycosuria without hyperglycemia that resolved within days. Following a second neurosurgical procedure, the patient again developed glycosuria, now associated with ketonuria. Further examination demonstrated nonalbuminuric proteinuria in conjunction with urinary wasting of phosphate and potassium, indicative of proximal tubule impairment. We suggest that transient proximal tubule impairment may play a role in the proteinuria and glycosuria described following volatile anesthetic exposure and discuss the relationship between these observations and the ability of these agents to protect against ischemic nephropathy.

Renal and hepatic integrity in long-term sevoflurane sedation using the anesthetic conserving device: a comparison with intravenous propofol sedation in an animal model

INTRODUCTION

Critically ill patients are sedated with intravenous agents because the use of inhaled agents is limited by their potential risk of toxicity. Increasing levels of inorganic fluorides after the metabolism of these agents have been considered potentially nephrotoxic. However, hepatic involvement after prolonged administration of sevoflurane has not yet been studied. The present study evaluated the potential renal and hepatic toxicity caused by prolonged administration (72h) of sevoflurane.

METHODS

For this experimental, prospective, randomized, controlled trial, 22 Landrace x Large-White female pigs were randomly assigned to two groups: intravenous propofol (P) or inhaled sevoflurane via the AnaConDa™ device (S, end-tidal 2.5 vol%). The P group remained sedated for 108h with propofol. In the S group, sevoflurane was administered for 72h and then changed to propofol for the remaining 36h in order to observe the kinetics of fluoride after discontinuation of sevoflurane. Serum creatinine was the primary outcome variable, but inorganic fluoride concentrations and other renal, hepatic, and cardiorespiratory variables were also measured.

RESULTS

Both groups of animals were comparable at baseline. No differences were found between the two groups for plasma creatinine and urea or creatinine clearance throughout the study. Fluoride levels were significantly higher in the sevoflurane group. No correlation was found between inorganic fluoride and serum creatinine values. No significant differences were observed for hepatic function. Hemodynamic, respiratory, and blood gas variables were comparable between the groups.

CONCLUSIONS

Long-term sedation with sevoflurane using AnaConDa™ or propofol does not negatively affect renal or hepatic function.

Short-term sevoflurane sedation using the Anaesthetic Conserving Device after cardiothoracic surgery

OBJECTIVE

We evaluated the procedure of postoperative inhalational sedation with sevoflurane using the Anaesthetic Conserving Device (ACD) with regard to recovery times, feasibility and consumption of anaesthetics in comparison to propofol.

DESIGN AND SETTING

Prospective, randomised, single-blinded, controlled study in a surgical intensive care unit (ICU) of a 1,000-bed academic hospital.

PATIENTS AND INTERVENTIONS

A total of 70 patients after elective coronary artery bypass graft surgery either received sevoflurane via ACD (n = 35) or propofol (n = 35) for short-term postoperative sedation in the ICU.

MEASUREMENTS AND MAIN RESULTS

The primary endpoint was extubation time from termination of sedation. Recovery times, consumption of anaesthetics, endtidal sevoflurane concentrations, length of ICU and hospital stay, and side effects were documented. Mean recovery times were significantly shorter with sevoflurane than with propofol (extubation time: 22 vs. 151 min; following commands: 7 vs. 42 min). The mean (SD) sevoflurane consumption was 3.2 +/- 1.4 mL/h to obtain mean endtidal concentrations of 0.76 vol%. No serious complications occurred during sedation with either sedative drug. The length of ICU stay was comparable in both groups, but hospital length of stay was significantly shorter in the sevoflurane group. Drug costs (in Euro) for sedation per patient were similar in both groups (sevoflurane: 15.1 +/- 9.5 <euro>; propofol: 12.5 +/- 5.8 <euro>), while sevoflurane sedation costs that included use of the ACD were significantly higher.

CONCLUSIONS

Sevoflurane administration via ACD is an effective and safe alternative to propofol to provide postoperative short-term ICU sedation. Recovery from sedation was facilitated with sevoflurane instead of propofol and resulted in shorter extubation and ventilator times.

DESCRIPTOR

Neurology/sedation, Sedation and anaesthesia.