Anaesthesia machine: Checklist, hazards, scavenging

Abstract

From a simple pneumatic device of the early 20th century, the anaesthesia machine has evolved to incorporate various mechanical, electrical and electronic components to be more appropriately called anaesthesia workstation. Modern machines have overcome many drawbacks associated with the older machines. However, addition of several mechanical, electronic and electric components has contributed to recurrence of some of the older problems such as leak or obstruction attributable to newer gadgets and development of newer problems. No single checklist can satisfactorily test the integrity and safety of all existing anaesthesia machines due to their complex nature as well as variations in design among manufacturers. Human factors have contributed to greater complications than machine faults. Therefore, better understanding of the basics of anaesthesia machine and checking each component of the machine for proper functioning prior to use is essential to minimise these hazards. Clear documentation of regular and appropriate servicing of the anaesthesia machine, its components and their satisfactory functioning following servicing and repair is also equally important. Trace anaesthetic gases polluting the theatre atmosphere can have several adverse effects on the health of theatre personnel. Therefore, safe disposal of these gases away from the workplace with efficiently functioning scavenging system is necessary. Other ways of minimising atmospheric pollution such as gas delivery equipment with negligible leaks, low flow anaesthesia, minimal leak around the airway equipment (facemask, tracheal tube, laryngeal mask airway, etc.) more than 15 air changes/hour and total intravenous anaesthesia should also be considered.

Unexpected anesthetic leakage from a damaged O-ring on the Selectatec back bar -A case report-

“…In addition, the anesthesiologist should be well acquainted with the concepts that underlie the subsystems of modern anesthetics and should not disregard any defects in these systems. Although advances in patientmonitoring skills and the automated check functions of the latest anesthesia machines help to prevent many problems, it is still necessary to be well-informed on the appropriate pre-use inspections of anesthesia equipment [13,14]. Therefore, prior to initiating anesthesia, it is required to perform pre-use leak tests using the checklists for anesthesia equipment issued in 1993…”

Critical incident is a possibility with water in flowmeter

“…Water condensation can pose problems in the mechanical, electrical and electronic components of the newer anaesthesia workstation. [ 6 ] Influx of water in a flowmeter when the anaesthesia workstation is in use can jeopardise patient safety, leading to critical incidents. The accumulated water can cause erratic or no movement of the bobbin in the flowmeter, resulting in inaccurate flow of anaesthetic gases.…”

Failure of Anaesthetic Machine Automated Self-Check to detect massive leak in Ventilator Bellows

“…We would recommend that clinicians should not rely completely on the electronic self-checks. At the very least, leak tests as described [9] should be performed before each case, even if the self-checks are performed. Furthermore, we have sought out to inform the manufacturer of the problem, in order to possibly update the electronic self-test.…”