Assessment of safe endotracheal tube cuff pressures in emergency care - time for change?

Abstract

To the Editor: Endotracheal intubation is performed in the prehospital and emergency department (ED) environments by advanced life support (ALS) paramedics and emergency doctors. Cuffed endotracheal tubes (ETTs) are used in adults and more recently in children 1 to ensure that the airway is protected, and to prevent air leakage between the wall of the trachea and the ETT during positivepressure ventilation. Cuffs are typically high volume, low pressure in their design and have a safe working pressure of <30 cm H 2 O in adults 2 and <20 cm H 2 O in children.1 Over-inflation of ETT cuffs to pressures exceeding 30 cm H 2 O may result in serious complications including tracheal stenosis, tracheal rupture and tracheo-oesophageal fistula.3 Tracheal injury may occur after as little as 15 minutes with ETT cuff pressures exceeding 27 cm H 2 O.2 To avoid tracheal injury due to emergency intubation, it is important that ETT cuff over-inflation is avoided in the pre-hospital and ED phases of emergency care.Although ETT cuff pressure manometry is optimal in determining safe ETT cuff pressure, it is standard practice in the ED and in the pre-hospital emergency care environment to assess ETT cuff pressure using palpation of the cuff 's pilot balloon -a qualitative technique prone to subjective interpretation. AimsThe aims of the study were to describe the ability of a convenience sample of practising ALS paramedics and emergency doctors in Johannesburg to accurately estimate safe ETT cuff pressures using palpation of the cuff 's pilot balloon alone, and to determine whether there was any dependence between correctness of ETT cuff estimation and the practitioner's years of clinical experience and estimated monthly number of intubations. MethodsEach one of seven 7.5 mm internal diameter ETTs (Microcuff ETT, Kimberley-Clarke, Zaventem, Belgium) was placed in a single 20 ml syringe barrel to simulate a trachea. Each syringe barrel was covered with an opaque material to prevent the participant seeing the cuff inside the syringe. The ETT cuffs were inflated to seven different pressures (0, 10, 20, 40, 60, 80 and 100 cm H 2 O), using an electronic ETT cuff manometer (TRACOE Cuff Pressure Control, TRACOE Medical GmbH, Frankfurt, Germany).A convenience sample of ALS paramedics and emergency doctors was selected from various private and metropolitan emergency medical services in the Greater Johannesburg region, the Department of Surgery at the University of the Witwatersrand, and the Master of Science in Medicine (Emergency Medicine) student body at the University of the Witwatersrand. Each consenting participant was asked to complete a short questionnaire documenting their qualifications, years of clinical experience and estimated number of intubations per month. Participants were then presented with the seven described ETTs, in random order. After palpating each of the seven ETT pilot balloons, each participant verbally indicated one of three options: (i) pressure too low; (ii) safe pressure; or (iii) pressure too high. Results were ...

Measurement of endotracheal tube cuff pressure: Instrumental versus conventional method

“…[ 8 ] Digital balloon palpation corresponds poorly with the measured endotracheal cuff pressure, and anesthetist experience corresponds poorly with measured cuff pressures. [ 8 10 11 12 ] The instrumental measurement and adjustment of cuff pressure resulted in a significantly lower incidence of postprocedural sore throat, hoarseness, and blood-stained expectorant. [ 12 ] The pressure exerted on the tracheal wall depends on the compliance of the trachea and the pressure measured at the pilot balloon of an ETT cuff.…”

“…[ 8 10 11 12 ] The instrumental measurement and adjustment of cuff pressure resulted in a significantly lower incidence of postprocedural sore throat, hoarseness, and blood-stained expectorant. [ 12 ] The pressure exerted on the tracheal wall depends on the compliance of the trachea and the pressure measured at the pilot balloon of an ETT cuff. ETT cuff pressure can be considered as a good estimate of the pressure exerted on the tracheal mucosa.…”

Endotracheal tube cuff pressures and tube position in critically injured patients on arrival at a referral centre: Avoidable harm?

“…Numerous studies have shown that palpation of the pilot-balloon has no correlation with the actual pressure in the cuff and the sensitivity is around 50% in most studies. 10 , 15 , 23 , 26 While this is a well-known fact, few prehospital, emergency centre or anaesthesia services use cuff-manometry as the standard of care. Studies in paramedic systems have consistently demonstrated cuff over-inflation in services not using routine cuff-pressure monitoring and part of the challenge lies in the varied recommended range of pressures that are considered acceptable (between 20 and 45 cm H 2 O).…”

Intraoperative management of ETT and LMA cuff pressures: a survey of anaesthetists’ knowledge, attitude and current practice

“…A study done by Stein et al highlighted the inability of advanced life support paramedics and emergency department doctors in Johannesburg to accurately estimate safe ETT cuff pressures using the palpation technique alone. 11 Multiple studies have found serious complications following longer duration of intubation, with the incidence and severity increasing proportionally to the duration. Cuff pressure itself may also change over time.…”