Washout of sevoflurane from the GE Avance and Amingo Carestation anesthetic machines

Consensus guidelines on perioperative management of malignant hyperthermia suspected or susceptible patients from the European Malignant Hyperthermia Group

Malignant hyperthermia is a potentially fatal condition, in which genetically predisposed individuals develop a hypermetabolic reaction to potent inhalation anaesthetics or succinylcholine. Because of the rarity of malignant hyperthermia and ethical limitations, there is no evidence from interventional trials to inform the optimal perioperative management of patients known or suspected with malignant hyperthermia who present for surgery. Furthermore, as the concentrations of residual volatile anaesthetics that might trigger a malignant hyperthermia crisis are unknown and manufacturers' instructions differ considerably, there are uncertainties about how individual anaesthetic machines or workstations need to be prepared to avoid inadvertent exposure of susceptible patients to trigger anaesthetic drugs. The present guidelines are intended to bundle the available knowledge about perioperative management of malignant hyperthermia-susceptible patients and the preparation of anaesthesia workstations. The latter aspect includes guidance on the use of activated charcoal filters. The guidelines were developed by members of the European Malignant Hyperthermia Group, and they are based on evaluation of the available literature and a formal consensus process. The most crucial recommendation is that malignant hyperthermia-susceptible patients should receive anaesthesia that is free of triggering agents. Providing that this can be achieved, other key recommendations include avoidance of prophylactic administration of dantrolene; that preoperative management, intraoperative monitoring, and care in the PACU are unaltered by malignant hyperthermia susceptibility; and that malignant hyperthermia patients may be anaesthetised in an outpatient setting.

Anesthetic management of an 8-month-old infant with osteogenesis imperfecta undergoing liver transplantation: a case report

Anesthetic management of pediatric liver transplantation in a patient with osteogenesis imperfecta (OI) requires tough decisions and comprehensive considerations of the cascade of effects that may arise and the required monitoring. Total intravenous anesthesia (TIVA) with propofol and remifentanil was chosen as the main anesthetic strategy. Malignant hyperthermia (MH), skeletal fragility, anhepatic phase during liver transplantation, uncertainties of TIVA in children, and propofol infusion syndrome were considered and monitored. There were no adverse events during the operation. Despite meticulous precautions with regard to the risk of MH, there was an episode of high fever (40℃) in the ICU a few hours after the operation, which was initially feared as MH. Fortunately, MH was ruled out as the fever subsided soon after hydration and antipyretics were given. Although the delivery of supportive care and the administration of dantrolene are the core principles in the management of MH, perioperative fever does not always mean a MH in patients at risk for MH, and other common causes of fever should also be considered.

Washout times of desflurane, sevoflurane and isoflurane from the GE Healthcare Aisys® and Avance®, Carestation®, and Aestiva® anesthesia system

BACKGROUND/AIM

Malignant hyperthermia susceptible patients may experience a fatal reaction to volatile anesthetic gases. This study sought to determine the washout characteristics of desflurane, sevoflurane, and isoflurane from the Aisys® , Avance® , and Aestiva® anesthesia machines. (GE Healthcare, Madison, WI, USA).

METHODS

All machines were inspected by a GE Healthcare engineer prior to testing. The machines were primed with desflurane 7 vol%, sevoflurane 2.5 vol%, and isoflurane 1.2 vol% on three separate occasions for 2 h each with each gas. The Aisys® and Avance® were tested with and without an Advanced Breathing System (ABS™ , GE Healthcare, Madison, WI, USA). The Aestiva® was tested without modification to its breathing system. Additionally, the Aisys was evaluated with desflurane 1.2 vol% and the Avance with a preflushed fresh gas line was tested with an autoclaved ABS. After priming, disposable components of the patient breathing system were replaced. The fresh gas flow was increased to 15 lpm. Gas measurements were recorded until the concentration was 4 parts per million (p.p.m).

RESULTS

The fastest median washout time was achieved by the Avance in 3 min or less without an ABS or with an autoclaved ABS. The longest median time was 35 min for the Aestiva® . Clearance of desflurane was the most time consuming for all machines.

CONCLUSION

This study demonstrates that saturated vapor pressure and priming concentration exert a greater effect on washout times than gas solubility. The Aisys utilizes an electronic vaporizer system that may expose the breathing system to retained saturated vapor. The breathing systems for all machines may hinder washout of gases.

[Anesthetic malignant hyperthermia: what's new in 2012?]

Malignant hyperthermia (MH) is a pharmacogenetic disorder of anesthesia. Recent advances dealing with epidemiology of MH and the safe anesthetic course of MH susceptible patients are shortly presented here with a special insight into the preparation of modern anesthesia workstations, which they will share in operating room.