Developing a standard for endotracheal tube cuff care

Potential complications from the use of cuffed endotracheal tubes are well documented and have generated a large body of research focusing on cuff design and interventions to decrease tracheal damage caused by the cuffs. The authors conducted a state-wide survey to determine the extent to which these procedures were incorporated into practice and to develop a current standard of care for patients with cuffed endotracheal tubes.     

Continuous real time endotracheal tube cuff pressure waveform

Endotracheal tube cuff pressure monitoring is one of the standard degrees of care afforded to anesthetized patients in the operative theater. Traditional pressure transducer when used to monitor cuff pressure provides real time continuous sine wave pressure waveform which has not been described in literature so far. This unique waveform needs to be further processed and evaluated to check its utility in airway pressure monitoring.     

The accurate measurement of endotracheal tube cuff pressures

The effects of endotracheal tube cuff pressure upon the tracheal wall is well documented and researched. Hyperinflation causes mucosal damage subsequent to restricted capillary blood flow (Seegobin and Hasselt, 1984), and underinflation increases aspiration risk (Bernard et al, 1979). There are critical care areas with no method of obtaining accurately cuff pressure other than adopting the minimal occlusion technique, i.e. inserting just enough air into the cuff to prevent air leakage. Although this is a useful method for obtaining an adequate seal, it does not safeguard against hyperinflation. The aim of this study was to demonstrate that without accurate measurement of intracuff pressures of endotracheal tubes, pressure will be outside the normal recommended limits, which could place patients at risk. Accurate measurements of cuff pressures post cardiac surgery were recorded using a Malincrodt pressure gauge. Theatre staff and intensive care unit nursing staff were unaware of the study until its completion. It is concluded that cuff pressures are too high using the minimal occlusion technique and the cuffs are prone to leaking.     

Synchronized intermittent mandatory insufflation of the endotracheal tube cuff

Continuous inflation of endotracheal tube cuffs causes tracheal injury in up to 11% of intubated patients. To avoid this complication and its consequences of tracheal and laryngeal stenosis and tracheosophageal fistula, we designed a simple device which enables intermittent inflation of the cuff during inspiratory periods of mechanical ventilation. This was achieved by connecting the inlet of the cuff of the pressure regulating tubing of the expiratory valve of a Bennett respirator. We have used the device in 25 patiens with prolonged intubation. There was no air leak around the tube, no aspiration of gastric content, and no late complications as shown by direct laryngoscopy at 1 week, 1 month, and 3 months after extubation, and by X-ray of the upper airway.     

气管导管套囊不同充气方法的比较

目的比较气管导管套囊的不同充气方法,获得理想的套囊充气方法。方法连续观察60例气管插管与气管切开并行机械通气的患者,按随机数字表分为3组,分别给予3种不同的方法给套囊充气:①指感法;②最小封闭压力法;③套囊测压表法。比较不同方法的操作时间、气道漏气发生率及气囊压力。结果套囊测压表组套囊压力控制最理想,为(28.85±2.3)cmH2O,与另两组比较,差异有统计学意义(P0.05)。结论套囊测压表法简便、有效、安全。     

Laboratory evaluation of 4 brands of endotracheal tube cuff inflator

INTRODUCTION: Routine measurement of endotracheal tube (ETT) cuff pressure is a standard in respiratory care, and several devices are available for measuring ETT cuff pressure. Yet an informed choice in the buying process is hindered by the present paucity of unbiased, comparative data. METHODS: Four brands of cuff inflator were tested: Posey Cufflator, DHD Cuff-Mate 2, Rüsch Endotest, and SIMS-Portex Cuff Pressure Indicator. Ten randomly selected 8.0-mm-inner-diameter ETTs were modified and tested in a trachea model. The cuffs were gradually inflated and deflated. After each sequential change in cuff volume, cuff pressure measurements were simultaneously recorded with the cuff inflator and with a calibration analyzer. These data were compared using limits-of-agreement analysis. Then, with each of the 10 ETTs, each cuff inflator was used to measure 3 known (ie, measured with the calibration analyzer) cuff pressures: 20, 40, and 60 cm H(2)O. Cuff pressure measurements were averaged, by brand, and compared to the respective baseline cuff pressure. Finally, using the 10 ETTs and trachea model, the ETT cuffs were inflated, in 0.25-mL increments, using only a syringe and the calibration analyzer. The cuff pressure and cuff volume data from that procedure were plotted and the best-fit regression line was determined. RESULTS: There were differences in bias and precision among the tested cuff inflators. The Cuff-Mate 2 had the smallest bias and best precision. None of the cuff inflator brands accurately measured cuff pressure. In each case the Cuff-Mate 2 measured cuff pressures closest to actual. The Cuff-Mate 2 contains about half the compressible volume of that in the Endotest and Cufflator and < 20% of that in the Cuff Pressure Indicator. Regarding the relationship between cuff pressure and intracuff volume, the best-fit linear regression equation was: cuff volume = 0.05 x CP - 0.39 (r(2) = 0.96). CONCLUSIONS: The 4 cuff inflators tested differ in bias and precision and none of the devices accurately measure cuff pressure. Cuff inflator manufacturers should design an accurate yet reasonably priced device to inflate ETT cuffs, and ideally that device should allow cuff-pressure checks without decreasing cuff pressure. In the meanwhile clinicians may opt to use my proposed cuff-pressure measurement technique, which minimizes the loss of cuff pressure during cuff-pressure checks and provides more accurate cuff-pressure measurements.     

Continuous endotracheal tube cuff pressure control system protects against ventilator-associated pneumonia

Introduction

The use of a system for continuous control of endotracheal tube cuff pressure reduced the incidence of ventilator-associated pneumonia (VAP) in one randomized controlled trial (RCT) with 112 patients but not in another RCT with 142 patients. In several guidelines on the prevention of VAP, the use of a system for continuous or intermittent control of endotracheal cuff pressure is not reviewed. The objective of this study was to compare the incidence of VAP in a large sample of patients (n = 284) treated with either continuous or intermittent control of endotracheal tube cuff pressure.

Methods

We performed a prospective observational study of patients undergoing mechanical ventilation during more than 48 hours in an intensive care unit (ICU) using either continuous or intermittent endotracheal tube cuff pressure control. Multivariate logistic regression analysis (MLRA) and Cox proportional hazard regression analysis were used to predict VAP. The magnitude of the effect was expressed as odds ratio (OR) or hazard ratio (HR), respectively, and 95% confidence interval (CI).

Results

We found a lower incidence of VAP with the continuous (n = 150) than with the intermittent (n = 134) pressure control system (22.0% versus 11.2%; p = 0.02). MLRA showed that the continuous pressure control system (OR = 0.45; 95% CI = 0.22-0.89; p = 0.02) and the use of an endotracheal tube incorporating a lumen for subglottic secretion drainage (SSD) (OR = 0.39; 95% CI = 0.19-0.84; p = 0.02) were protective factors against VAP. Cox regression analysis showed that the continuous pressure control system (HR = 0.45; 95% CI = 0.24-0.84; p = 0.01) and the use of an endotracheal tube incorporating a lumen for SSD (HR = 0.29; 95% CI = 0.15-0.56; p < 0.001) were protective factors against VAP. However, the interaction between type of endotracheal cuff pressure control system (continuous or intermittent) and endotracheal tube (with or without SSD) was not statistically significant in MLRA (OR = 0.41; 95% CI = 0.07-2.37; p = 0.32) or in Cox analysis (HR = 0.35; 95% CI = 0.06-1.84; p = 0.21).

Conclusions

The use of a continuous endotracheal cuff pressure control system and/or an endotracheal tube with a lumen for SSD could help to prevent VAP in patients requiring more than 48 hours of mechanical ventilation.     

气管导管套囊压力术中管理的研究进展

气管导管套囊在机械通气中,可起防止气道漏气,预防呼吸机相关性肺炎的作用。套囊压力管理是气管插管患者气道管理中的一个重要环节。深入了解气管导管套囊压力的影响因素及管理方法,能更好地为气管插管术后套囊相关并发症的防治提供参考。     

Evaluation of manual cuff palpation to confirm proper endotracheal tube depth

INTRODUCTION: In the prehospital setting, optimal endotracheal tube (ETT) depth may be approximated using the patient's sex or height, and assessed by auscultation. Even when using these methods, the ETTs still may be placed at inappropriate depths. PROBLEM: This study assessed the inter-rater reliability and accuracy of manual cuff palpation (ballottement) at excluding an improperly placed ETT depth in adult patients. METHODS: This is a prospective, observational, pilot study in a convenience sample of adults recently intubated in the prehospital, medical floor, intensive care unit, or emergency department settings of an urban, teaching hospital. Two physician participants separately performed ballottement on each intubated subject and rated the ballottement as none, weak, or strong prior to assessment of appropriate depth using a chest radiograph (CXR). Results were compared for simple agreement and compared to the CXR to estimate accuracy. RESULTS: Of 163 patients, 27 (17%) had an inappropriate ETT depth. Physician assessments of ballottement agreed in 79% of patients (95% CI = 72-85%). Chest radiograph assessment found the ETT in the "strong" ballottement group properly placed in 93%, as compared to 77% in the "weak", and 42% in the "none" groups. Combining "weak" and "strong" ballottement, the sensitivity was 96% (95% CI = 93-100%), specificity was 26% (95% CI = 9-43%), and accuracy was 85% (95% CI = 79-90%). CONCLUSIONS: Manual cuff palpation is a simple and reproducible technique that is sensitive, but nonspecific, in identifying intubations of appropriate depth.     

Comparison of endotracheal tube cuff pressure values before and after training seminar

It is recommended that endotracheal cuff (ETTc) pressure be between 20 and 30 cm H₂O. In this present study, we intend to observe average cuff pressure values in our clinic and the change in these values after the training seminar. The cuff pressure values of 200 patients intubated following general anesthesia induction in the operating theatre were measured following intubation. One hundred patients whose values were measured before the training seminar held for all physician assistants, and 100 patients whose values were measured after the training seminar were regarded as Group 1 and Group 2, respectively. Cuff pressures of both groups were recorded, and the difference between them was shown. Moreover, cuff pressure values were explored according to the working period of the physician assistants. There was no significant difference between the groups in terms of age, gender and tube diameters. Statistically significant difference was found between cuff pressure values before and after the training (p?<?0.001). Average pressure measure for Group I was 54 cm H₂O, while average pressure in Group II declined to 33 cm H₂O. It was observed that as the working period and experience of physician assistants increased, cuff pressure values decreased, however no statistically significant different was found (p?<?0.375). We believe that clinical experience does not have significant effects on cuff pressure and that training seminars held at intervals would prevent high cuff pressure values and potential complications.     

Prehospital use of a prototype esophageal detection device: a word of caution!

OBJECTIVE: To determine the effectiveness of a prototype esophageal detection device (EDD) during use in the prehospital setting. DESIGN/SETTING: Prospective convenience sample in a prehospital setting. POPULATION: Intubated adult patients. INTERVENTIONS: The study device was used to determine esophageal or endotracheal placement of endotracheal tubes in intubated patients. Clinical means were used to confirm tube location. A data sheet was completed for each patient. RESULTS: Of 105 uses of the device, 17 of 17 esophageal tubes were identified correctly (100% sensitivity). Sixty-five of 88 tracheal tubes were correctly identified (78% specificity). There was intermediate reinflation of the device on 13 of the 65 tracheal tubes. Five tests were indeterminate. There were no false negatives (negative predictive value 100%), but 18 false positives (positive predictive value 48%). CONCLUSION: This prototype EDD adequately identifies esophageally placed endotracheal tubes. Correct identification of endotracheally placed tubes was less sensitive. Much work needs to be done regarding the use of negative aspiration devices to identify placement of endotracheal tubes.     

对机械通气患者气管套管气囊压力的临床观察

目的判断机械通气患者气管套管气囊压力和注气量是否合适。方法对30例机械通气老年患者的气管套管气囊压力和注气量的实际值和理想值进行精确测量。结果53.3％的患者气囊实际压力和注气量过高，大于理想值。其中气囊实际注气量大于理想注气量3～5ml，气囊压力超过理想压力2～26cmH2O(0．2～2．6kPa)。结论临床大部分气管套管气囊压力和注气量偏高，应对机械通气患者的气管套管压力和注气量定期进行精确测量和调整，以减少气管套管对气管粘膜的损伤。