Renal toxicity with sevoflurane: a storm in a teacup?

Renal safety of critical care sedation with sevoflurane: a systematic review and meta-analysis

Volatile anesthetic agents are increasingly widely used for critical care sedation. There are concerns that sevoflurane presents a risk of renal injury when used in this role. RCTs comparing the use of critical care sevoflurane sedation with any control in humans were systematically identified using MEDLINE, Cochrane CENTRAL, web of Science, and CINAHL (until May 2022), if they presented comparative data on renal function or serum inorganic fluoride levels. Pooled SMDs (95% CI) were calculated where possible after assessment of quality with GRADE and risk of bias with ROB-2. Eight studies analyzing 793 patients were included. The median duration of use of critical care sevoflurane sedation was 4.8 [IQR 3.5-9.2] hours; however, most trials also included a period of prior intraoperative use. No significant difference was found in serum creatinine at 1 day (SMD 0.05, 95% CI - 0.12 to 0.21), 48 h (SMD = - 0.04; 95% Cl - 0.25 to 0.17), 72 h (SMD = - 0.15; 95% CI - 0.45 to 0.15), and at discharge (SMD = - 0.1; 95% CI - 0.3 to 0.13) between the sevoflurane group and the control groups. Creatinine clearance was measured in two studies at 48 h with no significant difference (SMD = - 0.13; 95% Cl - 0.38 to 0.11). Levels of serum inorganic fluoride were significantly elevated in patients where sevoflurane was used. Sevoflurane was not associated with renal failure when used for critical care sedation of fewer than 72-h duration, despite the elevation of serum fluoride. Longer-term studies are currently inadequate, including in patients with compromised renal function, to further evaluate the role of sevoflurane in this setting.Trial registration PROSPERO (CRD42022333099).

Brain DNA damaging effects of volatile anesthetics and 1 and 2 Gy gamma irradiation in vivo: Preliminary results

Although both can cause DNA damage, the combined impact of volatile anesthetics halothane/sevoflurane/isoflurane and radiotherapeutic exposure on sensitive brain cells in vivo has not been previously analyzed. Healthy Swiss albino male mice (240 in total, 48 groups) were exposed to either halothane/sevoflurane/isoflurane therapeutic doses alone (2 h); 1 or 2 gray of gamma radiation alone; or combined exposure. Frontal lobe brain samples from five animals were taken immediately and 2, 6, and 24 h after exposure. DNA damage and cellular repair index were analyzed using the alkaline comet assay and the tail intensity parameter. Elevated tail intensity levels for sevoflurane/halothane were the highest at 6 h and returned to baseline within 24 h for sevoflurane, but not for halothane, while isoflurane treatment caused lower tail intensity than control values. Combined exposure demonstrated a slightly halothane/sevoflurane protective and isoflurane protective effect, which was stronger for 2 than for 1 gray. Cellular repair indices and tail intensity histograms indicated different modes of action in DNA damage creation. Isoflurane/sevoflurane/halothane preconditioning demonstrated protective effects in sensitive brain cells in vivo. Owing to the constant increases in the combined use of radiotherapy and volatile anesthetics, further studies should explore the mechanisms behind these effects, including longer and multiple exposure treatments and in vivo brain tumor models.

Renal injury from sevoflurane in noncardiac surgery: a retrospective cohort study

BACKGROUND

Sevoflurane is metabolised into Compound A and fluoride that carry a hypothetical risk of nephrotoxicity. However, a clinically significant association between sevoflurane use and acute kidney injury (AKI) in humans has not been established.

METHODS

We retrospectively reviewed 15 552 patients who underwent noncardiac surgery under general anaesthesia using a volatile agent lasting >3 h between July 2016 and May 2019 at a single centre. Patients were divided into a sevoflurane group or no sevoflurane group (desflurane or isoflurane). The primary outcome was incidence of postoperative AKI, which was defined based on the Kidney Disease: Improving Global Outcomes criteria using creatinine concentration within 48 h postoperatively. Propensity score analysis using inverse probability of treatment weighting and propensity score matching was designed to compare outcomes between groups.

RESULTS

Amongst 13 701 included patients, 11 070 (80.8%) received sevoflurane during anaesthesia. The incidence of AKI was 2.3% (257/11 070) and 2.5% (66/2631) in the sevoflurane and no sevoflurane groups, respectvely (P=0.57). After inverse probability of treatment weighting adjustment, sevoflurane anaesthesia was not significantly associated with postoperative AKI (odds ratio [OR] 1.32; 95% confidence interval [CI]: 0.99-1.76; P=0.059). In the matched cohort, the incidence of AKI was 3.1% (81/2626) and 2.4% (62/2626) in the sevoflurane and no sevoflurane groups, respectively, and sevoflurane anaesthesia was not associated with postoperative AKI (OR 1.32; 95% CI: 0.94-1.86; P=0.11).

CONCLUSIONS

Sevoflurane anaesthesia for >3 h was not associated with postoperative renal injury compared with anaesthesia using other volatile agents.

Anesthesia and the renal sympathetic nervous system in perioperative AKI

Approximately 7% of patients undergoing non-cardiac surgery with general anesthesia develop postoperative acute kidney injury (AKI). It is well-known that general anesthesia may have an impact on renal function and water balance regulation, but the mechanisms and potential differences between anesthetics are not yet completely clear. Recently published large animal studies have demonstrated that volatile (gas) anesthesia stimulates the renal sympathetic nervous system more than intravenous propofol anesthesia, resulting in decreased water and sodium excretion and reduced renal perfusion and oxygenation. Whether this is the case also in humans remains to be clarified. Increased renal sympathetic nerve activity may impair renal excretory function and oxygenation and induce structural injury in ischemic AKI models and could therefore be a contributing factor to AKI in the perioperative setting. This review summarizes anesthetic agents' effects on the renal sympathetic nervous system that may be important in the pathogenesis of perioperative AKI.

Nephrogenic Diabetes Insipidus following an Off-Label Administration of Sevoflurane for Prolonged Sedation in a COVID-19 Patient and Possible Influence on Aquaporin-2 Renal Expression

During the recent COVID-19 pandemic, the rapidly progressive shortage of intravenous sedative drugs led numerous intensive care units to look for potential alternatives in patients requiring mechanical ventilation for severe acute respiratory distress syndrome (ARDS). Inhalational sedation using the AnaConDa® device for sevoflurane administration is a possible option. In a 54-year-old COVID-19 patient with severe ARDS requiring extracorporeal membranous oxygenation (ECMO), sevoflurane on AnaConDa® device was administered for 8 days but was complicated by the development of nephrogenic diabetes insipidus (NDI). Other causes of NDI or central diabetes insipidus were reasonably excluded, as in other previously published cases of NDI in ICU patients receiving prolonged sevoflurane-based sedation. In addition, the postmortem examination suggested a lower expression of aquaporin-2 in renal tubules. This observation should prompt further investigations to elucidate the role of aquaporin-2 in sevoflurane-related NDI. Inhaled isoflurane sedation is a possible alternative.

The Triple Bottom Line and Stabilization Wedges: A Framework for Perioperative Sustainability

We present a narrative review of environmental sustainability aimed at perioperative clinicians. The review will familiarize readers with the triple bottom line framework, which aims to align the goals of delivering high-quality patient care, promoting environmental sustainability, and improving the financial position of health care organizations. We introduce the stabilization wedges model for climate change action adopted for the perioperative setting and discuss areas in which perioperative leaders can make sustainable choices. The goal of this review is to increase awareness among perioperative physicians of the environmental impacts of surgical and anesthetic care, promote engagement with sustainability efforts as a topic of professional concern for our specialty, and inspire new research in perioperative environmental sustainability.

Pogostone inhibits the activity of CYP3A4, 2C9, and 2E1 in vitro

CONTEXT

Pogostone possesses various pharmacological activities, which makes it widely used in the clinic. Its effect on the activity of cytochrome P450 enzymes (CYP450s) could guide its clinical combination.

OBJECTIVE

To investigate the effect of pogostone on the activity of human CYP450s.

MATERIALS AND METHODS

The effect of pogostone on the activity of CYP450s was evaluated in human liver microsomes (HLMs) compared with blank HLMs (negative control) and specific inhibitors (positive control). The corresponding parameters were obtained with 0-100 μM pogostone and various concentrations of substrates.

RESULTS

Pogostone was found to inhibit the activity of CYP3A4, 2C9, and 2E1 with the IC₅₀ values of 11.41, 12.11, and 14.90 μM, respectively. The inhibition of CYP3A4 by pogostone was revealed to be performed in a non-competitive and time-dependent manner with the K_i value of 5.69 μM and the KI/K_inact value of 5.86/0.056/(μM/min). For the inhibition of CYP2C9 and 2E1, pogostone acted as a competitive inhibitor with the K_i value of 6.46 and 7.67 μM and was not affected by the incubation time.

DISCUSSION AND CONCLUSIONS

The inhibitory effect of pogostone on the activity of CYP3A4, 2C9, and 2E1 has been disclosed in this study, implying the potential risk during the co-administration of pogostone and drugs metabolized by these CYP450s. The study design provides a reference for further in vivo investigations to validate the potential interaction.

DNA damage assessment in peripheral blood of Swiss albino mice after combined exposure to volatile anesthetics and 1 or 2 Gy radiotherapy in vivo

PURPOSE

Patient immobilization by general volatile anesthesia (VA) may be necessary during medical radiology treatment, and its use has increased in recent years. Although ionizing radiation (IR) is a well-known genotoxic and cytotoxic agent, and VA exposure has caused a range of side effects among patients and occupationally exposed personnel, there are no studies to date comparing DNA damage effects from combined VA and single fractional IR dose exposure.

MATERIAL AND METHODS

We investigate whether there is a difference in white blood cells DNA damage response (by the alkaline comet assay) in vivo in 185 healthy Swiss albino mice divided into 37 groups, anesthetized with isoflurane/sevoflurane/halothane and exposed to 1 or 2 Gy of IR. Blood samples were taken after 0, 2, 6 and 24 h after exposure, and comet parameters were measured: tail length, tail intensity and tail moment. The cellular DNA repair index was calculated to quantify the efficiency of cells in repairing and re-joining DNA strand breaks following different treatments.

RESULTS

In combined exposures, halothane caused higher DNA damage levels that were dose-dependent; sevoflurane damage increase did not differ significantly from the initial 1 Gy dose, and isoflurane even demonstrated a protective effect, particularly in the 2 Gy dose combined exposure. Nevertheless, none of the exposures reached control levels even after 24 h.

CONCLUSION

Halothane appears to increase the level of radiation-induced DNA damage, while sevoflurane and isoflurane exhibited a protective effect. DNA damage may have been even greater in target organs such as liver, kidney or even the brain, and this is proposed for future study.

Newer Volatile Anesthetic Agents in Cardiac Anesthesia: Review of Literature

Myocardial protection with volatile anesthetic agents have been suggested by multiple studies. These studies, however, are scattered and are often limited to a particular aspect of cardiac anesthesia. Older inhalational agents like halothane is known to cause significant hepatic damage in patients undergoing long duration surgeries while isoflurane is known to have marked vasodilating properties that also affects the coronary arteries leading to coronary “steal” phenomenon. Additionally, newer agents, like sevoflurane and desflurane, have shown more prominent cardioprotective effects than older agents. We searched ScholarOne, Medline, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library. The medical subject headings (MeSH) terms “anaesthesia, inhalational,” “anaesthesia, intravenous, or TIVA,” and “Cardiac anaesthesia or Cardiac Surgery” were used. Additional studies were identified by review of the reference sections of all eligible studies. The aim of this review article is to bring together the evidences with newer inhalational agents and provide a holistic view of their benefits and shortcomings in cardiac anesthesia.

Long-Term Inhalative Sedation in Children With Pulmonary Diseases

OBJECTIVES

To describe safety and feasibility of long-term inhalative sedation (LTIS) in children with severe respiratory diseases compared to patients with normal lung function with respect to recent studies that showed beneficial effects in adult patients with acute respiratory distress syndrome (ARDS).

DESIGN

Single-center retrospective study.

SETTING

12-bed pediatric intensive care unit (PICU) in a tertiary-care academic medical center in Germany.

PATIENTS

All patients treated in our PICU with LTIS using the AnaConDa® device between July 2011 and July 2019.

MEASUREMENTS AND MAIN RESULTS

Thirty-seven courses of LTIS in 29 patients were analyzed. LTIS was feasible in both groups, but concomitant intravenous sedatives could be reduced more rapidly in children with lung diseases. Cardiocirculatory depression requiring vasopressors was observed in all patients. However, severe side effects only rarely occured.

CONCLUSIONS

In this largest cohort of children treated with LTIS reported so far, LTIS was feasible even in children with severely impaired lung function. From our data, a prospective trial on the use of LTIS in children with ARDS seems justified. However, a thorough monitoring of cardiocirculatory side effects is mandatory.

1-1-8 one-step sevoflurane wash-in scheme for low-flow anesthesia: simple, rapid, and predictable induction

Background

Sevoflurane is suitable for low-flow anesthesia (LFA). LFA needs a wash-in phase. The reported sevoflurane wash-in schemes lack simplicity, target coverage, and applicability. We proposed a one-step 1-1-8 wash-in scheme for sevoflurane LFA to be used with both N₂O and Air. The objective of our study was to identify time for achieving each level of alveolar concentration of sevoflurane (F_AS) from 1 to 3.5% in both contexts.

Methods

We recruited 199 adults requiring general anesthesia with endotracheal intubation and controlled ventilation—102 in group N₂O and 97 in group Air. After induction and intubation, a wash-in was started using a fresh gas flow of O₂:N₂O or O₂:Air at 1:1 L·min^− 1 plus sevoflurane 8%. The ventilation was controlled to maintain end-tidal CO₂ of 30–35 mmHg.

Results

The rising patterns of F_AS and inspired concentration of sevoflurane (F_IS) are similar, running parallel between the groups. The F_AS/F_IS ratio increased from 0.46 to 0.72 within 260 s in group N₂O and from 0.42 to 0.69 within 286 s in group Air. The respective time to achieve an F_AS of 1, 1.5, 2, 2.5, 3, and 3.5% was 1, 1.5, 2, 3, 3.5, and 4.5 min in group N₂O and 1, 1.5, 2, 3, 4, and 5 min in group Air. The heart rate and blood pressure of both groups significantly increased initially then gradually decreased as F_AS increased.

Conclusions

The 1-1-8 wash-in scheme for sevoflurane LFA has many advantages, including simplicity, coverage, swiftness, safety, economy, and that it can be used with both N₂O and Air. A respective F_AS of 1, 1.5, 2, 2.5, 3, and 3.5% when used with N₂O and Air can be expected at 1, 1.5, 2, 3, 3.5, and 4.5 min and 1, 1.5, 2, 3, 4, and 5 min.

Trial registration

This study was retrospectively registered with ClinicalTrials.gov (NCT03510013) on June 8, 2018.

Perioperative considerations for kidney and pancreas-kidney transplantation

Kidney transplantation is the treatment of choice in patients with end-stage renal disease, as it improves survival and quality of life. Living donor kidney transplant prior to pancreas transplantation, or simultaneous pancreas and kidney transplantation are discussed. Patients usually present comorbidities and extensive preoperative workups are recommended, especially cardiac assessment, though type and frequency of surveillance is not established. Nephroprotective strategies include adequate fluid status and goal-directed therapy. The conventional use of diuretics has not demonstrated a real nephroprotective effect at follow-up. Thromboprophylaxis regimes, especially for the pancreatic graft outcome, are of importance. Notably, transplantation in the obese population has increased in recent decades. Strict preoperative evaluation and pulmonary considerations must be kept in mind. Finally, robotic kidney transplant is a recent approach that presents anesthetic challenges, mainly related to steep Trendelenburg position and fluid restriction.

Comparison of the Effects of Propofol and Sevoflurane Induced Burst Suppression on Cerebral Blood Flow and Oxygenation: A Prospective, Randomised, Double-Blinded Study

OBJECTIVE

Pharmacologically induced electroencephalogram (EEG) silence increases tolerance of ischemic period by reducing cerebral metabolism. We hypothesized that sevoflurane, a cerebral vasodilator, will maintain cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO₂) better than propofol, a cerebral vasoconstrictor, during EEG silence. To validate this, we compared the effect of sevoflurane and propofol on CBF and CMRO₂ during surgical plane of anasthesia (SP) and burst suppression on EEG (BS).

METHODS

We conducted a prospective, double-blinded trial where patients undergoing neurosurgery were randomized to receive propofol or sevoflurane. Mean velocity (MV) and pulsatility index (PI) of bilateral middle cerebral arteries (MCA) were measured as surrogate of CBF. Jugular venous oxygen saturation (SjvO₂) and arteriovenous oxygen difference (AjvDO₂) were obtained to assess CMRO₂. The values were compared between groups using Student t test and within the group with analysis of variance at SP and BS.

RESULTS

BS decreased MV and increased PI in propofol group (P < 0.001 and P < 0.02 on normal side, P < 0.004 and P < 0.001 on tumor side). There was no significant change in sevoflurane group. BS with sevoflurane increased SjvO₂ (P < 0.001) and decreased AjvDO₂ (P < 0.001). Change in SjvO₂ and AjvDO₂ with propofol at SP and BS was variable.

CONCLUSIONS

In our study, sevoflurane had a safer profile on cerebral oxygenation during BS while not altering the CBF, suggesting increased availability of oxygen. Propofol, on the other hand, produced cerebral vasoconstriction with BS. The effect of propofol on oxygenation was unpredictable, with low SjvO₂ and high AjvDO₂ even at surgical plane of anesthesia.

General Anesthetic Agents and Renal Function after Nephrectomy

The association between the choice of general anesthetic agents and the risk of acute kidney injury (AKI) and long-term renal dysfunction after nephrectomy has not yet been evaluated. We reviewed 1087 cases of partial or radical nephrectomy. The incidence of postoperative AKI, new-onset chronic kidney disease (CKD) and CKD upstaging were compared between general anesthetic agent groups (propofol, sevoflurane, and desflurane). Four different propensity score analyses were performed to minimize confounding for each pair of comparison (propofol vs. sevoflurane; propofol vs. desflurane; sevoflurane vs. desflurane; propofol vs. volatile agents). Study outcomes were compared before and after matching. Kaplan-Meier survival curve analysis was performed to compare renal survival determined by the development of new-onset CKD between groups up to 36 months after nephrectomy. Propofol was associated with a lower incidence of AKI (propofol 23.2% vs. sevoflurane 39.5%, p = 0.004; vs. propofol 21.0% vs. desflurane 34.3%, p = 0.031), a lower incidence of CKD upstaging (propofol 27.2% vs. sevoflurane 58.4%, p < 0.001; propofol 32.4% vs. desflurane 48.6%, p = 0.017) and better three-year renal survival after nephrectomy compared to sevoflurane or desflurane group (Log-rank test propofol vs. sevoflurane p < 0.001; vs. desflurane p = 0.015) after matching. Propofol was also associated with a lower incidence of new-onset CKD after nephrectomy compared to sevoflurane after matching (p < 0.001). There were no significant differences between sevoflurane and desflurane. However, subgroup analysis of partial nephrectomy showed a significant difference only in CKD upstaging. In conclusion, propofol, compared to volatile agents, could be a better general anesthetic agent for nephrectomy to attenuate postoperative renal dysfunction. However, limitations of the retrospective study design and inconsistent results of the subgroup analysis preclude firm conclusions.

A systematic review and narrative synthesis on the histological and neurobehavioral long-term effects of dexmedetomidine

BACKGROUND

Recent experimental studies suggest that currently used anesthetics have neurotoxic effects on young animals. Clinical studies are increasingly publishing about the effects of anesthesia on the long-term outcome, providing contradictory results. The selective alpha-2 adrenergic receptor agonist dexmedetomidine has been suggested as an alternative nontoxic sedative agent.

AIMS

The aim of this systematic review was to assess the potential neuroprotective and neurobehavioral effects of dexmedetomidine in young animals and children.

METHODS

Systematic searches separately for preclinical and clinical studies were performed in Medline Ovid and Embase on February 14, 2018.

RESULTS

The initial search found preclinical (n = 661) and clinical (n = 240) studies. A total of 20 preclinical studies were included. None of the clinical studies met the predefined eligibility criteria. Histologic injury by dexmedetomidine was evaluated in 11 studies, and was confirmed in three of these studies (caspase-3 activation or apoptosis). Decrease of injury caused by another anesthetic was evaluated in 16 studies and confirmed in 13 of these. Neurobehavioral tests were performed in seven out of the 20 studies. Of these seven rodent studies, three studies tested the effects of dexmedetomidine alone on neurobehavioral outcome in animals (younger than P21). All three studies found no negative effect of dexmedetomidine on the outcome. In six studies, outcome was evaluated when dexmedetomidine was administered following another anesthetic. Dexmedetomidine was found to lessen the negative effects of the anesthetic.

CONCLUSION

In animals, dexmedetomidine was found not to induce histologic injury and to show a beneficial effect when administered with another anesthetic. No clinical results on the long-term effects in children have been identified yet.

A Review of Anesthetic Effects on Renal Function: Potential Organ Protection

BACKGROUND

Renal protection is a critical concept for anesthesiologists, nephrologists, and urologists, since anesthesia and renal function are highly interconnected and can potentially interfere with one another. Therefore, a comprehensive understanding of anesthetic drugs and their effects on renal function remains fundamental to the success of renal surgeries, especially transplant procedures. Some experimental studies have shown that some anesthetics provide protection against renal ischemia/reperfusion (IR) injury, but there is limited clinical evidence.

SUMMARY

The effects of anesthetic drugs on renal failure are particularly important in the context of kidney transplantation, since the conditions of preservation following removal profoundly influence the recovery of organ function. Currently, preservation procedures are typically based on the usage of a cold-storage solution. Some anesthetic drugs induce anti-inflammatory, anti-necrotic, and anti-apoptotic effects. A more thorough understanding of anesthetic effects on renal function can present a novel approach for developing organ-protective strategies. The aim of this review is to discuss the effects of different anesthetic drugs on renal function, with particular focus on IR injury. Many studies have demonstrated the organ-protective effects of some anesthetic drugs, specifically propofol, which indicate the potential of some anesthetics to introduce novel organ protective targets. This is not surprising, since lipid emulsions are major components of propofol, which accumulating data show provide organ protective effects against IR injury. Key Messages: Thorough understanding of the interaction between anesthetic drugs and renal function remains fundamental to the delivery of safe perioperative care and to optimizing outcomes after renal surgeries, particularly transplant procedures. Anesthetics can be repurposed for organ protection with more information about their effects, especially during transplant procedures. Here, we review the effects of different anesthetic drugs - specifically those that contain lipids in their structure, with special reference to IR injury.

Comparison of Two Different Inhalation Anesthetics on Grafted Kidney Function in Patients Undergoing Renal Transplantation Surgery: Desflurane or Sevoflurane?

BACKGROUND

Anesthetic management of patients during renal transplantation is vitally important for ensuring proper functioning of kidneys that have undergone ischemia-reperfusion damage. The goal of this prospective study was to compare the effects of 2 different inhalation agents (sevoflurane and desflurane) on grafted kidney function in renal transplantation surgery.

METHODS

Sixty-five patients who were scheduled for living donor renal transplantation were enrolled in the study. General anesthesia was performed on all patients. Thirty-five pairs of recipients and donors were anesthetized with sevoflurane (group S) and 30 pairs of recipients and donors were anesthetized with desflurane (group D). Each patient's demographic characteristics, immunologic and clinical data, and hemodynamic parameters were recorded. The estimated glomerular filtration rate was calculated in the preoperative period and on postoperative days 1 and 7. The blood samples were collected before the operation and on postoperative days 1 and 7 for measurement of serum creatinine, neutrophil gelatinase-associated lipocalin, and interleukin 18.

RESULTS

There were no significant differences in demographic characteristics or immunologic data between group D and group S. Intraoperative heart rate and mean arterial blood pressure were the same between groups. Creatinine, estimated glomerular filtration rate, neutrophil gelatinase-associated lipocalin, and interleukin 18 values did not differ between groups (P > .05) in the preoperative period and postoperative days 1 and 7.

CONCLUSIONS

Sevoflurane and desflurane had no adverse effects on grafted kidney functions according to short-term graft outcomes in patients undergoing living donor renal transplantation.

Anesthesia maintenance with 'induction dose only' sevoflurane during pediatric ophthalmic examination: comparison with standard low-flow technique through a randomized controlled trial

BACKGROUND

Sevoflurane is preferred for pediatric day care procedures. However, financial and environmental costs remain major limitations. Induction dose of sevoflurane could itself be sufficient for maintaining anesthesia with low fresh gas flow during short noninvasive procedures.

METHODS

Fifty children, aged 1-5 years, scheduled for ophthalmic examination under anesthesia, were randomized into two groups. All children were induced with 8% sevoflurane in O₂ : N₂ O (40 : 60). In the Group S, anesthesia was maintained with 2% sevoflurane at 1 l·min^-1 fresh gas flow [O₂ : N₂ O = 50 : 50]. In Group L, the sevoflurane vaporizer was turned off and fresh gas flow was reduced to 0.5 l·min^-1 [O₂ : N₂ O = 50 : 50]. HR, BP, MAC, BIS, total sevoflurane consumption, ocular deviation, body movement, time to laryngeal mask airway removal (T_WO ), and airway complications were compared between the groups. Rescue propofol bolus was used, if needed.

RESULTS

Median duration of examination was 14 min (IQR = 9-17) in Group S and 15 min (IQR = 10-17) in Group L. Sevoflurane consumption was lower in the Group L (7 ml) compared to Group S (9 ml) [median difference = 2 ml, P < 0.001, 95% CI = 0.96-3.04]. T_WO was lower in Group L (86 s) compared to Group S (131 s) [median difference = 45 s, P = 0.002, 95% CI = 19.85-70.15]. There was no difference in hemodynamic parameters, incidence of ocular deviation, movement or airway complications, and need for rescue propofol.

CONCLUSION

Induction dose of sevoflurane is, in itself, adequate for maintaining anesthesia for short noninvasive ophthalmic examinations lasting approximately 15 min. This method significantly reduces sevoflurane consumption and cost.

Sevoflurane Induced Diffuse Alveolar Hemorrhage in a young patient

We report a very rare case of Sevoflurane Induced Diffuse Alveolar Hemorrhage in a previously healthy young adult in the post-operative period following general anesthesia. Diffuse alveolar hemorrhage (DAH) associated with inhalation injury from halogenated gases is a unique entity in the literature that practicing clinicians should be cognizant of and considered in post-operative cases of acute respiratory distress whereby other etiologies have been excluded.

Anesthesia specific differences in a cardio-pulmonary resuscitation rat model; halothane versus sevoflurane

OBJECTIVE

Our asphyxia cardiac arrest (ACA) rat model is well established. The original model was designed in the 1990th using halothane and nitrous oxide for pre-insult anesthesia. Because of its hepato-toxicity and its potential to induce severe liver failures, halothane is no longer used in clinical anesthesia for several years. In order to minimize the health risk for our laboratory staff as well as to keep the experimental settings of our model on a clinically oriented basis we decided to replace halothane by sevoflurane. In this study we intended to determine if the change of the narcotic gas regiment causes changes in the neurological damage and how far our model had to be adjusted.

METHODS

Adult rats were subjected to 5min of ACA followed by resuscitation. There were four treatment groups: ACA - halothane, ACA - sevoflurane and with halothane or sevoflurane sham operated animals. Vital and blood parameters were monitored during the 45min post-resuscitation intensive care phase. After a survival time of 7 days histological evaluation of the hippocampus was performed.

RESULTS

We observed that resuscitated rats anesthetized prior by sevoflurane (i) have had a lower heart rate and a higher MAP compared to halothane anesthetized animals; (ii) The neurological damaged were significantly reduced in the hippocampal CA1 region in sevoflurane treated rats.

CONCLUSION

Using sevoflurane instead of halothane for anesthesia requires some physiological and experimental changes. However the model keeps its validity. Sevoflurane caused less pronounced neurodegeneration in the CA1 region of the hippocampus. This had to be considered in further resuscitation-studies containing sevoflurane as anesthetic. Institutional protocol number for animal studies: 42502-2-2-947 Uni MD.

Sevoflurane

Sevoflurane has been available for clinical practice for about 20 years. Nowadays, its pharmacodynamic and pharmacokinetic properties together with its absence of major adverse side effects on the different organ systems have made this drug accepted worldwide as a safe and reliable anesthetic agent for clinical practice in various settings.

Propofol as a panacea for acute kidney injury?

Yoo and colleagues report a small but provocative randomized clinical trial to prevent acute kidney injury in the setting of cardiopulmonary bypass surgery. Their article describes a trial of 112 patients undergoing valvular surgery with cardiopulmonary bypass who were randomized to receive sevoflurane (an inhaled anesthetic) or propofol for general anesthesia. The use of propofol was associated with a significant decrease in the rate of postoperative acute kidney injury.

The impact of genetic factors on response to anaesthetics

In recent years, exceptional progress has been observed in pharmacogenetics, i.e. investigations of inherited conditioning of the organism's response to drugs or xenobiotics. On the other hand, modern molecular biology techniques have been implemented, making it possible to perform studies determining the involvement of genetic factors in differing responses to agents employed in general anaesthesia. Unexpected and incorrect response of the organism to the administration of specific anaesthetics is most commonly associated with a genetic defect of the metabolic pathway of a given agent or its receptor. The majority of agents used in anaesthesia are metabolised in the liver by the cytochrome P450 superfamily enzymes (CYPs) and phase II drug-metabolising enzymes: glutathione S-transferases (GSTs), sulphotransferases (SULTs), UDP-glucuronosyltransferases (UGTs) and NAD(P)H:quinone oxidoreductase (NQO1). Propofol is presently widely used for gastrointestinal (GI) and several other procedures. Among genes associated with metabolism of the most commonly applied anaesthetics such as propofol and sevoflurane, the following ones can be mentioned: CYP2E1, CYP2B6, CYP2C9, GSTP1, UGT1A9, SULT1A1 and NQO1. Moreover, the basic mechanism of propofol action involves its interaction with an ionotropic receptor GABAA inhibiting transfer of nerve impulses. Molecular studies have shown that polymorphic changes in GABRG2 receptor gene turn out to be important in the propofol anaesthesia. Planning of optimal anaesthesia can be considerably assisted by the determination of genetic factors of prognostic value taking advantage of genotyping and making it possible to select anaesthetics and reduce risk of side effects as well as undesirable actions.

Complications of general anesthesia

A summary of complications associated with general anesthesia including their incidence, mechanism, risk factors, prevention strategies, and management is presented.

Effect of sevoflurane on grafted kidney function in renal transplantation

BACKGROUND

The objective of this retrospective study was to determine if there are any differences in grafted kidney function in recipients of kidney transplantation (KT) when donors and recipients were anesthetized with sevoflurane compared to desflurane.

METHODS

Seventy-three pairs of donors-recipients were anesthetized with sevoflurane (Sevo group) and 71 pairs were anesthetized with desflurane (Des group). We retrospectively investigated the blood urea nitrogen (BUN) levels, creatinine (Cr) levels, and estimated glomerular filtration rates (eGFR) of the recipients in both groups for 1 year postoperatively. We tested non-inferiority for serum creatinine at discharge and 1 year after KT. Short-term (1 year) outcomes of KT were assessed by the incidence of delayed graft function (DGF), acute rejection episodes (ARE), and graft failure.

RESULTS

There were no differences in BUN, Cr, eGFR, or outcomes of KT at 1 year postoperatively. Specifically, the 95% confidence interval for the difference in creatinine levels between the Sevo and Des groups was less than the margin of equivalence at the time of discharge and 1 year after surgery. The occurrences of DGF, ARE, and graft failure were comparable between the groups.

CONCLUSIONS

Compared to desflurane, sevoflurane had no adverse effects on grafted renal function or on the short-term outcome of renal transplantation.

[Retrospective comparative study between sevoflurane and propofol in maintaining anaesthesia during liver transplant: Effects on kidney and liver function]

OBJECTIVE

To compare the post-operative effects of sevoflurane versus propofol on liver and kidney function while maintaining anaesthesia in the orthotopic liver transplant (OLT), as well as to analyse the short-term survival as regards these functions.

PATIENTS AND METHODS

A retrospective analysis was conducted on patients subjected to an OLT between January 2002 and December 2009. Patients on pre-transplant haemodialysis, re-transplants, and hepatorenal transplants were excluded. The incidence of acute renal failure, initial dysfunction of the graft, reperfusion syndrome, rejection, and the transaminase peak depending value depending on the hypnotic used, were recorded.

RESULTS

About one-third (31.2%) of the patients developed acute renal failure and 11.9% an initial dysfunction, with no differences between the groups. There was a tendency for a lower incidence of initial dysfunction of the graft in the sevoflurane group (8.6% compared to 12.8%), a lower transaminase peak (greater than 2000 U/L, 12.1% versus 15.9%), and a lower incidence of reperfusion syndrome (10.3% compared to 21.6%).

CONCLUSIONS

Despite the fact that the renal metabolism sevoflurane is elevated, we did not find any higher incidence of acute renal failure. Sevoflurane in the liver transplant anaesthesia is as least equally as safe propofol as regards renal function and liver function. New prospective studies are needed to clarify the possible effects of the hypnotic in liver transplant.

Mechanism of Anesthetic Toxicity: Metabolism, Reactive Oxygen Species, Oxidative Stress, and Electron Transfer

There is much literature on the toxic effects of anesthetics. This paper deals with both the volatiles and locals. Adverse effects appear to be multifaceted, with the focus on radicals, oxidative stress (OS), and electron transfer (ET). ET functionalities involved are quinone, iminoquinone, conjugated iminium, and nitrone. The non-ET routes involving radicals and OS apparently pertain to haloalkanes and ethers. Beneficial effects of antioxidants, evidently countering OS, are reported. Knowledge at the molecular level should aid in devising strategies to combat the adverse effects.

Anesthetic concerns in patients presenting with renal failure

Anesthesiologists often care for patients with renal insufficiency or renal failure. These patients may present to the operating room for a minor procedure such as an inguinal hernia repair or an arteriovenous fistula/graft. Alternatively, they may present for major abdominal operations or coronary artery bypass grafting. Critically ill patients presenting to the operating room may have acute kidney injury. It is imperative that the anesthesiologist understands the ramifications of renal failure and adjusts the anesthetic plan accordingly. Hemodynamic monitoring and fluid management can be challenging in this patient population. Various metabolic abnormalities can ensue that the anesthesiologist must be able to manage in the acute setting of the operating room.

Patterns of sevoflurane use in a children's hospital: the effects of a simple educational intervention

We conducted a prospective observational study of sevoflurane use over a four-week period at our tertiary referral children's hospital. Sevoflurane vaporisers were weighed before and after all general anaesthesia sessions and anaesthesia time intervals recorded. Midway through the audit, the initial findings were presented to the department with a brief reminder of ways to reduce sevoflurane use. These included recommendations for fresh gas flows and use of alternative agents during maintenance. Sevoflurane use then continued to be audited over a further two-week period. Anaesthesia in induction rooms accounted for 60% of total sevoflurane use but involved only 15% of total general anaesthetic time. Thus sevoflurane was used eight times faster in the induction rooms when compared to operating theatres. There was a 53% reduction in the rate of use of sevoflurane after the educational intervention, with an 87% reduction in in-theatre use and a 31% reduction in induction room use. This represents a potential saving of $108,120 per annum in our institution. Workloads before and after the educational intervention were comparable. A more complete cost benefit analysis of this initiative would include the costs of alternative agents and any clinical disadvantages incurred and would be seen in the context of the overall health budget. This was beyond the scope of this project. Clinicians can be relatively complacent about financial accountability. In this study, a simple educational reminder halved sevoflurane use in the short term. This study suggests that specific reminders or recommendations about anaesthetic technique in the induction rooms may be indicated.

Inhaled anesthetic agents

PURPOSE

The pharmacology, bioavailability and pharmacokinetics, indications, clinical efficacy, adverse effects and toxicities, and dosage and administration of the inhaled anesthetics are reviewed.

SUMMARY

The inhaled anesthetics include desflurane, enflurane, halothane, isoflurane, and sevoflurane and are thought to enhance inhibitory postsynaptic channel activity and inhibit excitatory synaptic activity. The mechanism of action of inhaled anesthetics has not been completely defined. A number of factors can influence the pharmacokinetics of inhaled anesthetics, including solubility in blood, cardiac output, tissue equilibration, extent of tissue perfusion, metabolism, and age. All of the available inhaled anesthetics are effective for inducing or maintaining anesthesia or both. Most clinical trials of inhaled anesthetics have evaluated differences in induction and emergence from anesthesia by comparing (1) times to loss of reflex, extubation, and response to verbal commands; orientation to time and place; and ability to sit up without assistance, (2) need for post-surgical analgesia, and (3) time to discharge as measures of efficacy. Adverse effects and toxicities of the inhaled anesthetics include nephrotoxicity, hepatotoxicity, cardiac arrhythmias, neurotoxicity, postoperative nausea and vomiting, respiratory depression and irritation, malignant hyperthermia, and postanesthesia agitation. Safety issues surrounding these gases include occupational exposure and intraoperative fires within the delivery systems used with inhaled anesthetics. Drugs used for anesthesia during surgery can account for 5-13% of a hospital's drug budget.

CONCLUSION

The inhaled anesthetics have been shown to be both safe and effective in inducing and maintaining anesthesia. These agents differ in potency, adverse-effect profile, and cost. Newer anesthetic gases, such as sevoflurane and desflurane, appear to have more favorable physico-chemical properties. These factors, as well as patient characteristics and duration and type of procedure, must be considered when selecting an inhaled anesthetic.

Perioperative care of the patient with nephropathic cystinosis

Cystinosis is an autosomal recessive disease that results in a defective integral membrane protein responsible for the transport of cystine out of lysosomes. This results in the accumulation of cystine in the lysosomes of almost every tissue, with subsequent formation of damaging crystals. The cystinotic process may affect every system of the body, but is particularly damaging to the kidneys and eyes. We discuss the perioperative care of a cystinotic patient with renal insufficiency, Fanconi's syndrome, and photophobia. Other organ systems affected by the cystinotic process are also discussed, with suggestions for the perioperative management of each. Issues of primary concern during perioperative care include preservation of renal function and maintenance of fluid and electrolyte homeostasis.

Biological indices of kidney involvement in personnel exposed to sevoflurane in surgical areas

BACKGROUND

Fluoride, a main metabolite, and one degradation product of sevoflurane (SEV), called Compound A, are known to cause kidney effects in experimental animals. Other than in volunteers and patients, no research is available on exposed workers. The possible effects on the kidney in workers exposed in surgical areas were studied.

METHODS

Subjects exposed to SEV and nitrous oxide (N(2)O) in surgical areas (N = 61) using open (N = 25) or semi-closed (N = 36) circuits were submitted to biological monitoring. The same biological indices were determined in 43 controls also. Sevoflurane (SEVU), nitrous oxide (N(2)OU), total urinary proteins (TUP), N-acetyl-beta-D-glucosaminidase (NAGU), and glutamine synthetase (GSU) were measured in urine.

RESULTS

The mean values of environmental exposure were 31.3 ppm (range 0.9-111.6 ppm) for N(2)O and 0.28 ppm (range 0-1.88 ppm) for SEV. Exposed subjects had significantly higher excretion of TUP; a higher, not significant, excretion of GSU was also observed in subjects using open circuits. A significant correlation was found in all exposed subjects between NAGU and SEVU (r = 0.303, P < 0.05), GSU and N(2)OU (r = 0.382, P < 0.01) and, especially, GSU and SEVU (r = 0.650, P < 0.001). These correlations appeared to be influenced by the use of open circuits; infact, NAGU was well correlated to N(2)OU (r = 0.770, P < 0.001) and SEVU (r = 0.863, P < 0.001); GSU to N(2)OU (r = 0.468, P < 0.05) and SEVU (r = 0.735, P < 0.001).

CONCLUSIONS

Results show that no relevant effect on the kidney is present for the levels of exposure studied. Nevertheless, correlation between dose and response urinary indices supports that SEV, other than N(2)O, may influence kidney function, especially when open circuits are used.

Toxic, halogenated cysteine S-conjugates and targeting of mitochondrial enzymes of energy metabolism

Several haloalkenes are metabolized in part to nephrotoxic cysteine S-conjugates; for example, trichloroethylene and tetrafluoroethylene are converted to S-(1,2-dichlorovinyl)-L-cysteine (DCVC) and S-(1,1,2,2-tetrafluoroethyl)-L-cysteine (TFEC), respectively. Although DCVC-induced toxicity has been investigated since the 1950s, the toxicity of TFEC and other haloalkene-derived cysteine S-conjugates has been studied more recently. Some segments of the US population are exposed to haloalkenes either through drinking water or in the workplace. Therefore, it is important to define the toxicological consequences of such exposures. Most halogenated cysteine S-conjugates are metabolized by cysteine S-conjugate beta-lyases to pyruvate, ammonia, and an alpha-chloroenethiolate (with DCVC) or an alpha-difluoroalkylthiolate (with TFEC) that may eliminate halide to give a thioacyl halide, which reacts with epsilon-amino groups of lysine residues in proteins. Nine mammalian pyridoxal 5'-phosphate (PLP)-containing enzymes catalyze cysteine S-conjugate beta-lyase reactions, including mitochondrial aspartate aminotransferase (mitAspAT), and mitochondrial branched-chain amino acid aminotransferase (BCAT(m)). Most of the cysteine S-conjugate beta-lyases are syncatalytically inactivated. TFEC-induced toxicity is associated with covalent modification of several mitochondrial enzymes of energy metabolism. Interestingly, the alpha-ketoglutarate- and branched-chain alpha-keto acid dehydrogenase complexes (KGDHC and BCDHC), but not the pyruvate dehydrogenase complex (PDHC), are susceptible to inactivation. mitAspAT and BCAT(m) may form metabolons with KGDHC and BCDHC, respectively, but no PLP enzyme is known to associate with PDHC. Consequently, we hypothesize that not only do these metabolons facilitate substrate channeling, but they also facilitate toxicant channeling, thereby promoting the inactivation of proximate mitochondrial enzymes and the induction of mitochondrial dysfunction.