Fulminant hepatic failure following halothane anaesthesia

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.

A mouse model of severe halothane hepatitis based on human risk factors

Halothane (2-bromo-2-chloro-1,1,1-trifluoro-ethane) is an inhaled anesthetic that induces severe, idiosyncratic liver injury, i.e., "halothane hepatitis," in approximately 1 in 20,000 human patients. We used known human risk factors (female sex, adult age, and genetics) as well as probable risk factors (fasting and inflammatory stress) to develop a murine model with characteristics of human halothane hepatitis. Female and male BALB/cJ mice treated with halothane developed dose-dependent liver injury within 24 h; however, the liver injury was severe only in females. Livers had extensive centrilobular necrosis, inflammatory cell infiltrate, and steatosis. Fasting rendered mice more sensitive to halothane hepatotoxicity, and 8-week-old female mice were more sensitive than males of the same age or than younger (4-week-old) females. C57BL/6 mice were insensitive to halothane, suggesting a strong genetic predisposition. In halothane-treated females, plasma concentration of tumor necrosis factor-alpha was greater than in males, and neutrophils were recruited to liver more rapidly and to a greater extent. Anti-CD18 serum attenuated halothane-induced liver injury in female mice, suggesting that neutrophil migration, activation, or both are required for injury. Coexposure of halothane-treated male mice to lipopolysaccharide to induce modest inflammatory stress converted their mild hepatotoxic response to a pronounced, female-like response. This is the first animal model of an idiosyncratic adverse drug reaction that is based on human risk factors and produces reproducible, severe hepatitis from halothane exposure with lesions characteristic of human halothane hepatitis. Moreover, these results suggest that a more robust innate immune response underlies the predisposition of female mice to halothane hepatitis.

The age- and gender-dependent effects of desflurane and sevoflurane on rat liver

OBJECTIVE

This study aimed to investigate the age- and gender-dependent effects of desflurane and sevoflurane on the liver.

MATERIAL AND METHOD

Upon the approval of ethics committee, 84 rats were divided into four groups as 21 young male, 21 young female, 21 old male, and 21 old female rats. Then, each group was further divided into three groups as desflurane, sevoflurane, and control groups. Maintaining the minimum alveolar concentration of 1, desflurane at 6vol% and sevoflurane at 2vol% in 6Lmin(-1) 100% O2 were administered for 2h in a transparent plastic container of 40cmx40cmx70cm. Each liver preparation was evaluated for hydropic degeneration, nuclear polymorphism, portal neutrophile infiltration, portal lymphocyte infiltration, and focal necrosis, and each preparation was assigned injury points of 0-3; thus, the number of histopathologically injured cases, total injury scores of each preparation, and the mean injury scores of each group were determined.

RESULTS

Desflurane and sevoflurane did not significantly increase hepatic injury in the young male rats, while both agents caused significantly more hepatic injury in the young female rats. In the old rats, both desflurane and sevoflurane inflicted more hepatic injury on both genders. In addition, desflurane caused more hepatic injury in the old female rats than in the young female or the old male rats.

CONCLUSION

Hepatic injury associated with desflurane and sevoflurane was mild to moderate, suggesting that both agents can be safely used in routine anaesthesia procedures.

Halothane hepatitis in Iran: A review of 59 cases

AIM: To study halothane hepatitis (HH) in Iran and its associated risk factors.

METHODS: We retrospectively studied files of all cases diagnosed with HH referred to three referral hospitals and four private centers in Iran from April 1994 to September 2006. Information on age at surgery, gender, medications history, obesity, history of previous exposure, previous reaction to halothane, familial history, type of surgery, perioperative hypoxia or sepsis, morbidity and mortality were recorded and analyzed.

RESULTS: A total of 59 cases were identified. Forty-eight (81%) were women. The median age at the time of surgery was 44 years (range, 18 to 80 years). Sixty percent of patients were above 40-year-old. Obesity was observed in 22.2%. Previous history of exposures to halothane was noted in 61% of which 50% had history of post-exposure reaction. Coronary artery bypass graft (CABG), cholecystectomy, and cosmetic surgeries (mainly weight reduction) were the most frequent surgeries. The mortality rate was 12.2%. In patients developing encephalopathy, it was as high as 50%.

CONCLUSION: HH remains an important cause of morbidity and mortality in centers still using this anesthetic. However, a large percentage of these cases could have been avoided. To lessen occurrence of further cases of HH, the authors suggest that in female patients having a history of surgery (or delivery) with general anesthesia, the use of halothane should be absolutely avoided. Utilization of proper substitutes in adults’ anesthesia is advocated.

Maternal hepatotoxicity with nevirapine as part of combination antiretroviral therapy in pregnancy

OBJECTIVES

To describe the maternal tolerability of nevirapine as part of combination antiretroviral therapy in pregnancy at three HIV centres in Dublin, Ireland and to determine risk factors for development of significant hepatotoxicity.

METHODS

A retrospective study was carried out of all women prescribed nevirapine as part of combination antiretroviral therapy in pregnancy at three HIV centres in Dublin, Ireland (October 2000 to February 2003). Toxicities experienced were graded according to the Division of AIDS toxicity guidelines for adults. Statistical analysis was performed to determine whether there were differences between those that did and those that did not experience significant hepatotoxicity.

RESULTS

A total of 123 women initiated nevirapine as part of combination antiretroviral therapy in the study period. Eight women developed significant hepatotoxicity, including two women who died from fulminant hepatitis. Women who experienced more severe hepatotoxicity had higher pretreatment CD4 counts (P=0.01).

CONCLUSIONS

In this cohort, women who experienced more severe hepatotoxicity had higher pretreatment CD4 counts, lending additional weight to the need for caution in using nevirapine as part of combination antiretroviral therapy in women not requiring antiretroviral therapy for their own health.