Internal system failure of Drager Primus anaesthesia workstation because of inefficient humidification inside the operating room

Sir, The anaesthesia machine has most often been involved in equipment-related morbidity,[1] and this has led to the extensive use of preoperative checklists. Technical problems with the anaesthesia workstation are often reported.[2] The American Society of Anesthesiologists (ASA) has developed pre-anaesthesia checkout guidelines and these are widely accepted to be important components of safe anaesthesia practice. Incorporation of safety features in anaesthesia machines and ensuring a proper check-up of the machine is done before its use on a patient.[3] We report a critical incident related to the Drager Primus anaesthesia workstation (Dräger Medical GmbH, Lubeck, Germany) that took place despite a complete machine check as recommended by the Association of Anaesthetists of Great Britain and Ireland.[4] We describe this critical incident in a 28 years old ASA-1 female patient undergoing laparoscopic right nephrectomy under general anaesthesia. As a part of the routine protocol, the anaesthesia machine passed the daily checks through the electronic system self-test, and the breathing circuits were checked for any leaks. Following uneventful pre-oxygenation, general anaesthesia was induced as per standard protocol. After the start of surgery, the air conditioning system of the operating room (OR) became non-functional because of some technical issues and the humidity started to increase. Approximately 1 h after the incision, a sudden failure of the ventilator occurred. The anaesthesia workstation displayed ‘internal/system fault, the device cannot be used, ventilator failure, and manual ventilation available only’ [Figure 1]. No prior warning/safety alarm was activated. We immediately connected the co-axial Bain circuit to the auxiliary flow meter of the anaesthetic machine and initiated manual ventilation. We then checked all other possible causes of anaesthesia machine failure along with medical gas pipeline system misconnections. We replaced this non-functional workstation with another one and the surgery was completed uneventfully and the patient was shifted to recovery.Figure 1: Draeger Primus anaesthesia workstation display shows internal system faultOn literature search, about 15% of anaesthetic equipment failure is reported even after successfully passing the self-checks.[1] However, in our case, the reason for this internal system error was very uncommon. The Drager Company personnel on enquiry stated that the presence of moisture inside the display printed circuit board (PCB) called printed board assembly Mobi 4 [PBA Mobi-4] might have been a possible reason for this machine failure leading to an internal system error. Machine failure because of humidity is an uncommon occurrence. On literature search, only one case is reported in which abnormally high humidity in the OR caused moisture condensation in the alarm panel that resulted in an electronic short circuit.[5] The Drager Primus anaesthesia workstation is designed to work at a temperature of 15–40°C and humidity of 25–85%.[6] In India, the temperature and humidity increase during summers. At the time of failure of the workstation, the temperature and humidity of the OR were 32°C and 85%, respectively. The anaesthesia workstation manufacturer, Drager, should incorporate a warning system to indicate increasing humidity in the PCB and they should educate/warn the users of possible failure in case of increasing humidity more than 85%. The OR humidification should be routinely checked. However, routine validation of systems such as temperature, humidity check, air particulate count, air change rate calculation, pressure differential levels of the OR with respect to adjoining areas, and validation of high-efficiency particulate arrestance filters should be repeated after 6 months. Nevertheless, the National Accreditation Board for Hospitals and Healthcare Providers has recommended that periodic preventive maintenance of the system must be carried out in terms of cleaning of pre-filters, micro vee-filters, and pocket filters at an interval of 15–30 days.[7] To summarise, failure of the anaesthesia workstations is possible and a good knowledge of the workstation can help during these troublesome times. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.