BMC Anesthesiology | Full text | Prevalence and predictors of out-of-range cuff pressure of endotracheal and tracheostomy tubes: a prospective cohort study in mechanically ventilated patients

http://www.biomedcentral.com/1471-2253/15/147 http://www.biomedcentral.com/1471-2253/15/147

Abstract

Background

Maintaining the cuff pressure of endotracheal tubes (ETTs) within 20–30 cmH 2 O is a standard practice. The aim of the study was to evaluate the effectiveness of standard practice in maintaining cuff pressure within the target range.

Methods

This was a prospective observational study conducted in a tertiary-care intensive care unit, in which respiratory therapists (RTs) measured the cuff pressure 6 hourly by a handheld manometer. In this study, a research RT checked cuff pressure 2–4 h after the clinical RT measurement. Percentages of patients with cuff pressure levels above and below the target range were calculated. We identified predictors of low-cuff pressure.

Results

We analyzed 2120 cuff-pressure measurements. The mean cuff pressure was 27 ± 2 cmH 2 O by the clinical RT and 21 ± 5 cmH 2 O by the research RT (p < 0.0001). The clinical RT documented that 98.0 % of cuff pressures were within the normal range. The research RT found the cuff pressures to be within the normal range in only 41.5 %, below the range in 53 % and above the range in 5.5 %. Low cuff pressure was found more common with lower ETT size (OR, 0.34 per 0.5 unit increase in ETT size; 95 % CI, 0.15–0.79) and with lower peak airway pressure (OR per one cm H 2 O increment, 0.93; 95 % CI, 0.87–0.99) on multivariate analysis.

Conclusions

Cuff pressure is frequently not maintained within the target range with low-cuff pressure being very common approximately 3 h after routine measurements. Low cuff pressure was associated with lower ETT size and lower peak airway pressure. There is a need to redesign the process for maintaining cuff pressure within the target range.

In intubated patients, the cuff of an endotracheal tube (ETT) ensures proper sealing between the trachea and the ETT itself thus preventing air leaks during positive pressure ventilation and aspiration of oropharyngeal or gastric secretions and contents into the trachea. An observational study found that a peak airway pressure greater than 48 cm H 2 O requires a cuff pressure greater than 34 cm H 2 O to prevent an air leak <>[1]. Another one found that conventional high-volume, low-pressure cuffs may not prevent micro-aspiration even at cuff pressures up to 60 cm H 2 O <>[2]. However, excessive pressure may lead to several complications such as post extubation pain, tissue necrosis, bleeding, tracheal stenosis and rupture and tracheoesophageal fistulae <>[3]– <>[5]. Carefully balancing the risk of an air leak versus the risk of pressure necrosis in patients with a high peak airway pressure is needed. As a general guideline, the cuff pressure should be maintained between 20 and 30 cmH 2 O <>[6], which necessitates periodic measurements and adjustments of cuff pressure, which is the current practice in most intensive care units (ICUs). In one study, such a routine care of measuring cuff pressure with a manual manometer every 8 h was associated with cuff pressure less than 20 cm H 2 O in 45.3 % of patients <>[7].

Evidence-based guidelines for ventilator-associated pneumonia prevention recommend that the cuff pressure should be maintained at 20–30 cm H 2 O <>[8], <>[9]. However, these guidelines do not address the optimal frequency of cuff pressure measurements to maintain the cuff pressure within the recommended range and debate the use of continuous monitoring of ETT cuff pressure <>[10]. Additionally, the ventilator care bundle that has been recommended to prevent ventilator-associated pneumonia does not include maintaining cuff pressure within target range as part of its recommendations. The aim of the study is to determine the effectiveness of the current practice that is used in maintaining ETT cuff pressure within the recommended target range and to identify the predictors of failure to do so.

Robert Simms / Business Manager Novus Medical Inc. mobile +1- 905-407-3005 / office +1-866-926-9977 2333 Wyecroft Rd., Unit 9, Oakville, Ontario, L6L 6L4 Canada

visit novusmedical.ca http://novusmedical.ca/ for more medical innovation.