Ja. Williamson et al., THE CAPNOGRAPH - APPLICATIONS AND LIMITATIONS - AN ANALYSIS OF 2000 INCIDENT REPORTS, Anaesthesia and intensive care, 21(5), 1993, pp. 551-557
Citations number
22
Categorie Soggetti
Anesthesiology,"Emergency Medicine & Critical Care
The first 2000 incidents reported to the Australian Incident Monitorin
g Study were analysed with respect to the role of the capnograph. One
hundred and fifty-seven (8%) were first detected by a capnograph and t
here were a further 18 (1%) in which capnography was contributory. Of
the 1256 incidents which occurred in association with general-anaesthe
sia 48% were ''human detected'' and 52% ''monitor detected'' The capno
graph was ranked second and detected 24% of these monitor detected inc
idents; this figure would have been nearly 30% if a correctly checked,
calibrated capnograph had always been used. The capnograph is a ''fro
nt-line'' monitor for oesophageal intubation, failure of ventilation,
anaesthetic circuit faults, gas embolism, sudden circulatory collapse
and malignant hyperthermia. It is a valuable ''back-up'' monitor when
other monitors (eg. low pressure alarm, pulse oximeter) are not in use
, are being used incorrectly or fail. Such situations, in order of fre
quency of detection were: circuit-leak, overpressure of the breathing
circuit, bronchospasm, leak of ventilator-driving-gas into the patient
circuit, aspiration and/or regurgitation and hypoventilation. There w
ere 20 reports of ''failure'', over two-thirds of which would not have
occurred with appropriate checking and calibration. Seven were due to
gas sampling problems and 6 to apnoea alarm failure. Two circuit leak
s and 2 faulty unidirectional valves were not detected, on 3 occasions
problems occurred due to power failure, calibration problems, or misi
nterpretation of an alarm. In a theoretical analysis of the 1256 gener
al anaesthesia incidents it was considered that the capnograph, used o
n its own, would have detected 55% of these incidents, had they been a
llowed to evolve (43% before any potential for organ damage). It is hi
ghly recommended that a suitable, correctly checked, calibrated capnog
raph be used on all intubated and/or ventilated patients from the mome
nt of intubation until extubation, capnography is also useful in the '
'apnoea'' detection mode for patients breathing spontaneously on a mas
k.