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Indian J Anaesth. 2016 June; 60(6): 444–445.
PMCID: PMC4910494

Difficult bag mask ventilation: Catheter mount cap, a cause for concern


Use of disposable products is common in anaesthesia practice. Occasionally, aberrations can occur in this type of equipment. Failure to check equipment properly is an important factor leading to potential critical events. Proper checking of equipment before use may help prevent equipment-related morbidity and mortality, improve preventive maintenance and educate the provider about equipment.[1] Unfortunately, failure to perform a proper check before use is common.[2]

A 54-year-old female patient was posted for examination under anaesthesia and a cervical biopsy in the minor operation theatre. Prior to induction of general anaesthesia, the oxygen saturation was 99%. Following induction with fentanyl and propofol, we encountered a tight bag situation while using the face mask and could not ventilate the patient. There was no chest rise and no air entry on auscultation. We increased the depth of anaesthesia, optimised mask holding and used an oral airway. On visual inspection, the anaesthesia circuit assembly appeared appropriate. The bag continued to remain tight with no chest expansion, with no obvious reason for difficult mask ventilation. Post-induction, the oxygen saturation was 98%. The mask was disconnected from the circuit to connect to a self-inflating reservoir bag for ventilation, anticipating desaturation due to the lapsed time. The patient could be ventilated easily using the self-inflating reservoir bag. Much to our surprise, we saw a red-coloured cap occluding the mask, which was completely concealed when connected to the catheter mount [Figure 1a]. The red-coloured catheter mount cap was not removed before connecting to the mask and had resulted in the complete circuit obstruction [Figure 1b]. Once recognized, the cap was removed, the patient could be ventilated easily and the anaesthesia proceeded uneventfully.

Figure 1
(a) Catheter mount cap concealed in the mask, (b) complete obstruction of the mask with cap (viewed from above), (c) complete obstruction of the mask with cap (viewed from below), (d) catheter mount covered with cap

The red cap covering the catheter mount connected to the mask if not noticed on time could have led to potentially dangerous consequences. This was not a manufacturing defect, and interestingly, the cap fitted perfectly well into the mask [Figure 1c]. This was not detected through the mask as it was semi-opaque. These caps may often be transparent and may not be picked up even through a transparent mask. The catheter mount with the cap [Figure 1d] was connected to the mask by a new operating room technician who was unaware of the consequences. In a busy place like the minor operation theatre with a rapid turnover, due to paucity of time, things are often hurried leading to failure to perform a proper equipment check. A visual check may well have picked up the fault.[3] On doing a root cause analysis, we discovered that the circuit had been checked by the provider; however, the disposable catheter mount was attached in the circuit and fitted to the mask by the technician just prior to induction of anaesthesia and the cap thus went unnoticed. The anesthesia apparatus check-out recommendations[4] clearly states that though the technician may have a role in checking the equipment, the ultimate responsibility for ensuring that the equipment functions properly lies with the anaesthesia provider. Thus, failure to check the complete breathing system assembly may account for serious negligence on the part of the anaesthesia provider. This case reaffirms the importance of a complete cockpit drill before conducting anaesthesia.

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Conflicts of interest

There are no conflicts of interest.


1. Ravi PR, Shouche S. A curious case of blocked catheter mount. Med J Armed Forces India. 2013;69:313–4. [PMC free article] [PubMed]
2. Dorsch JA, Dorsch SE, editors. Understanding Anaesthesia Equipment. 5th ed. New Delhi: Lippincott Williams and Wilkins, Wolters Kluwer Business; 2008. Equipment checking and maintenance; pp. 931–54.
3. Adams AP, Morgan M. Checking anaesthetic machines – Checklists or visual aids? Anaesthesia. 1993;48:183–6. [PubMed]
4. Jeffrey MF, Michael AO, Donald M, Adam S. New Guidelines Available for Pre-Anesthesia Checkout. Anesthesia Patient Safety Foundation. 2008. [Last accessed on 2016 Apr 27]. p. 23. Available from: .

Articles from Indian Journal of Anaesthesia are provided here courtesy of Wolters Kluwer -- Medknow Publications