Safety first

European Journal of Anaesthesiology, vol. 37, pp. 837–838

Abstract

On a normal day in the operating room of a major European hospital, the anaesthesia machine was checked properly, as on every morning, and no technical defects were detected. The first patient of the day was carrying a multiresistant pathogen and only single use equipment including anaesthesia machine tubes was used. After the operation, new tubing was connected to the ventilator and the usual self-test was run. Again, no defects were detected. The next patient was eventually intubated, and the capnography initially was unremarkable. Saturation then started dropping. The patient was extubated again and manual ventilation with the anaesthesia machine was performed but remained unsuccessful. At that point, the anaesthesiologist understood that the root of the problem was the ventilator and he looked for the accessory ventilation bag and oxygen supply. However, no new ventilation bag had been put back into place after the first operation. Meanwhile, the patient had become hypoxic. An additional ventilation bag was quickly brought in while reintubation was performed and ventilation was finally possible. As the underlying cause, the team identified a misconnection of respirator tubes at the level of the water traps. Fortunately, in this instance, which was reported anonymously to the European Patient Safety Foundation (EuPSF; https://www.eupsf.org), no major consequences for the patient were entailed. However, this case falls in line with accumulating reports about incidents caused by wrong tube connections to the respirator. All of them emphasise the importance of checking the anaesthesia machine and assuring that an accessory ventilation bag is in place. Theissen et al.1 published four closed claims about serious adverse events and deaths because of incorrect ventilator use. Errors included the accidental connection of a patient to the exhalation valve of the transport ventilator, not turning on the ventilator, misconnection of the patient's breathing circuit to the anaesthesia machine, and ventilating a patient with a ventilator set to self-test mode. Three patients subsequently died whereas one survived in a permanent vegetative state. An analysis of the German Critical Incident Reporting system with regards to technical equipment and ventilation2 showed that 25% of reported incidents occurred because of an insufficient functional machine check. Another 25% were related to ventilation tubes or filters. In the United Kingdom, cases with blocked tubes have been described.3,4 In the United States, an evaluation of the ASA Closed Claims database showed that 85% of patient injuries related to anaesthesia gas delivery equipment involved a provider error with (n=7) or without (n=27) equipment failure.5 It was found that 35% of claims were judged as preventable if proper pre-anaesthesia machine check had been performed.5 In addition to the published data, the EuPSF has received three unpublished reports on the topic of wrong tube connections sent in as personal communications or upon inquiries from two countries. In Germany, recent case reports have also reached the Federal Institute for Drugs and Medical Devices and the German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie & Intensivmedizin, DGAI) resulting in a specified recommendation to perform a QUICKcheck of the anaesthesia workstation prior to every anaesthesia case.2,6,7 In seven cases published by the German Federal Institute for Drugs and Medical Devices, severe complications were entailed.7 Incidents of wrong tube connections constitute all ranges of adverse outcomes due to hypoxemia, including vegetative state and death. Considering the fact that databases to document critical incidents like these probably do not exist in every European country and that not every event is reported in countries where platforms are available, the number of unreported cases is estimated to be much higher. Consequently, a safety-alert on wrong tube connections to the respirator has been published by the EuPSF in collaboration with the European Society of Anaesthesiology (ESA), the German Society of Anaesthesiology and Intensive Care Medicine as well as the Swiss Anaesthesia Patient Safety Foundation (Stiftung für Patientensicherheit in der Anästhesie = SPSA) in May last year.8 Three main errors were highlighted: (1) An accidental shortcut of respirator tubes on the level of water traps. (2) The wrong connection of the manual ventilation bag on the expiratory connector of the ventilator. (3) Blocking of tubings (angle-piece, etc.) because of, for example, intravenous caps.8 Every anaesthesiologist is responsible for ensuring that the anaesthesia work station he/she is using is functioning and that an accessory ventilation bag is in place. It is crucial to note that the automatic ‘self-check’ of ventilators does not necessarily detect malfunctions of accessory aspects of the anaesthesia machine, such as wrong tube connections, leakages or defective soda lime cartridges.2,8 Discussions with manufacturers about improvements in this field are ongoing. In order to avoid wrong tube connections to the ventilator, it would be desirable to produce specific tubes with different diameters so that they can only be put together correctly in one way. However, no official technical requirements for the manufacture of the ventilators exist. For now, this responsibility lies solely with the anaesthesiologist in charge. It only takes 1 s to confirm that an additional ventilation bag is in place. And it takes less than 10 s to assess the gasflow function by a short pressure and flow test before induction of anaesthesia, to verify the presence of oxygen by measuring FiO2 and to ensure ventilation of the lungs by checking the capnography.2,9 These seconds could be decisive to save lives. For the pressure and flow test, the ventilator is disconnected from the patient, set in the ‘spontaneous/manual’ mode with the adjustable pressure-limiting valve (APL-valve) set at 30 mbar. While closing the patient connection port, the system is filled via the oxygen flush button. The machine's reservoir bag is then manually compressed and should not deflate. When the patient connection port is opened again, a detectable gas flow must occur. After connecting the patient to the ventilator and before changing to the mechanical ventilation mode, a few manual inflations should be made.2 In case of any irregularities, every anaesthesiologist should promptly recall switching to the manual ventilation bag and accessory oxygen supply, and if necessary, remove the airway device according to the saying: ‘If in doubt, take it out’.9,10 The EuPSF together with the ESA, DGAI and SPSA have outlined a ventilator checklist and a systematic trouble-shooting algorithm (available at https://www.eupsf.org/safety-alert-wrong-tube-connections).8,10,11 It is pivotal that we teach junior anaesthesiologists these essentials – ideally in simulation trainings.1,9,12 In stressful situations, analytical troubleshooting becomes challenging and it is helpful to rely on trained algorithms, such as in cardiopulmonary resuscitation (CPR) situations.9 Confirming that an accessory ventilation bag is in place and quickly checking gas flow function, presence of oxygen and carbon dioxide in addition to the standard ventilator testing should become as obvious as monitoring blood pressure or peripheral oxygen saturation. Due to a lack of appropriate databases, the extent of ventilator misuse and consecutive patient harm cannot be measured adequately up to date. Anaesthesia has never been as safe as today. Nevertheless, the reoccurring reports of severe patient harm associated with mechanical ventilator misuse should draw our attention to the simple yet effective measure of checking the anaesthesia machine first.

Authors 3

1. Linda Grüßer corresponding Aachen Department of Anaesthesiology, Medical Faculty to Linda Grüßer

   RWTH Aachen University · Paracelsus Medical University

   Affiliation as printed

   From the Department of Anaesthesiology, Medical Faculty RWTH Aachen University, Aachen, Germany (LG, RR), Department of Anaesthesiology and Intensive Care, Regional Hospital Männedorf/Zürich, Switzerland (SS) and Department of Anaesthesiology, Perioperative Medicine and Intensive Care, Paracelsus Medical University Salzburg, Austria (SS)

   Published online 22 April 2020

   e-mail: [email protected]

   fax: +49 241 80 82406

   the Department of Anaesthesiology, Medical Faculty RWTH Aachen University, Aachen, Germany (LG, RR), Department of Anaesthesiology and Intensive Care, Regional Hospital Männedorf/Zürich, Switzerland (SS) and Department of Anaesthesiology, Perioperative Medicine and Intensive Care, Paracelsus Medical University Salzburg, Austria (SS)

   to Linda Grüßer, Department of Anaesthesiology, Medical Faculty RWTH Aachen University, Aachen, Germany Tel: +49 241 80 88179

2. Sven E.A. Staender Aachen Department of Anaesthesiology, Medical Faculty

   RWTH Aachen University · Paracelsus Medical University

   Affiliation as printed

   Published online 22 April 2020

   the Department of Anaesthesiology, Medical Faculty RWTH Aachen University, Aachen, Germany (LG, RR), Department of Anaesthesiology and Intensive Care, Regional Hospital Männedorf/Zürich, Switzerland (SS) and Department of Anaesthesiology, Perioperative Medicine and Intensive Care, Paracelsus Medical University Salzburg, Austria (SS)

3. Rolf Rossaint Aachen Department of Anaesthesiology, Medical Faculty

   RWTH Aachen University · Paracelsus Medical University

   Affiliation as printed

   Published online 22 April 2020

   the Department of Anaesthesiology, Medical Faculty RWTH Aachen University, Aachen, Germany (LG, RR), Department of Anaesthesiology and Intensive Care, Regional Hospital Männedorf/Zürich, Switzerland (SS) and Department of Anaesthesiology, Perioperative Medicine and Intensive Care, Paracelsus Medical University Salzburg, Austria (SS)