Ventilation failure as a result of internal battery leakage in an Ulco Ev500 ventilator.
Article Type: Letter to the editor
Subject: Batteries (Safety and security measures)
Positive pressure respiration (Case studies)
Positive pressure respiration (Complications and side effects)
Ventilators (Product defects and recalls)
Ventilators (Safety and security measures)
Authors: Butler, C.
Gianotti, G.J.
Pub Date: 07/01/2011
Publication: Name: Anaesthesia and Intensive Care Publisher: Australian Society of Anaesthetists Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2011 Australian Society of Anaesthetists ISSN: 0310-057X
Issue: Date: July, 2011 Source Volume: 39 Source Issue: 4
Topic: Event Code: 260 General services; 350 Product standards, safety, & recalls
Product: Name: Ulco EV500 (Medical instrument); Ulco EV500 (Medical instrument) Product Code: 3841563 Respirators NAICS Code: 339113 Surgical Appliance and Supplies Manufacturing SIC Code: 3691 Storage batteries; 3692 Primary batteries, dry and wet; 3842 Surgical appliances and supplies
Accession Number: 264921648
Full Text: The provision of adequate ventilation is crucial to the safe conduct of anaesthesia. We present a case of partial ventilator failure due to the destruction of ventilator components as a result of leakage of acid from the ventilator's internal battery.

A 53-year-old man with a recent history of myocardial infarction and cardiogenic shock was anaesthetised for the insertion of an automatic implanted cardioverter defibrillator. Following induction and paralysis, he was intubated and intermittent positive pressure was maintained on an Ulco EV500 ventilator (Ulco Medical, Marrickville NSW) with a tidal volume of 500 ml and a peak inspiratory pressure of 18 cm[H.sub.2]O. The cardiologist experienced difficulty in accessing the left subclavian vein and the patient was positioned head-down. At this point the tidal volume became inadequate and the inspiratory pressure was adjusted higher.

We then noticed that the maximum inspiratory pressure that could be delivered was only 20 cm[H.sub.2]O so the patient was hand-ventilated until his position returned to horizontal. No obvious cause for the inadequate ventilation was found. The remainder of the procedure was uneventful, but the ventilator was exchanged at the end of the case.

On opening the ventilator it was found that the internal 6 volt sealed lead acid battery (required as backup in case of mains power failure) had leaked (Figure 1). Only when the ventilator was further dismantled was the degree of damage apparent. The acid from the battery had pooled onto the venturi block to an extent that its plastic structure had fragmented (Figure 2). This resulted in a large internal leak that led to the limitation in inspiratory pressure experienced clinically. The ventilator was also unable to provide end-expiratory pressure for the same reason. Despite the leak the electrical functions of the ventilator remained unaffected, with timing and alarm functions appearing to be normal. There was also no evidence from the external inspection of the ventilator that the acid leakage had occurred, nor was there any indication from the sound of the ventilator that such a problem existed.



We are unaware of any similar published reports of similar ventilator failure due to battery leakage, although the leakage of battery contents in an intensive care unit ventilator has been the cause of failure in the case of an interrupted mains power supply (1). The acid contents of the battery are clearly destructive to the internal components of the ventilator. The manufacturer recommends that the ventilator be serviced on a 12 month basis, but does not specifically recommend inspection or replacement of the sealed lead acid battery (2). We currently change this battery every two years.

We would suggest that inspection for leakage of internal batteries be part of the regular 12 month servicing of the ventilator, and be considered as a potential cause of their failure.


(1.) Amagasa S, Igarashi A, Yokoo N, Sato M. Backup failure of an adjuvant battery in an evita 4 ventilator. Anesthesiology 2008; 108:763-764.

(2.) Ulco Medical: EV500 Anaesthetic Ventilator User Manual. EV5-UM-001, version 2.6, 2006.



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