Variations in endotracheal cuff pressure in intubated critically ill patients: prevalence and risk factors

Improving the Endotracheal Tube Cuff Pressure Control Management Knowledge of Medical and Surgical Intensive Care Nurses: A Quasi-Experimental Study Pre-Post Test

The knowledge level of nurses' endotracheal tube (ETT) cuff pressure control management is important for patient safety. The aim of this study is to assess how the knowledge level of intensive care (ICU) nurses is affected by ETT cuff pressure control training delivered using 2 alternative teaching techniques. The research was conducted with 88 medical and surgical nurses working in ICUs. The nurses in the groups were given education with presentation techniques in line with evidence-based guidelines on ETT cuff pressure control management. In addition to the nurses in the experimental group, 4 one-on-one follow-up visits were made using the demonstration technique. A statistically significant difference was found between the total scores of the knowledge level of ETT cuff pressure control after training in the experimental group and control group (P < .001). It was determined that presentation and demonstration teaching techniques increased the knowledge level of nurses on ETT cuff pressure control management, and the use of demonstration and one-to-one follow-up strategies were most effective.

Relationship between difference in endotracheal tube cuff area and airway area with minimum cuff pressure for adequate airway sealing: a prospective observational study

It is essential for clinicians to select the appropriate endotracheal tube to ensure effective airway management. However, an unmatched endotracheal tube cuff area to the airway area can lead to air or secretion leakage, even at the recommended cuff pressure of 20-30 cmH2O. The present multicenter prospective observational study aimed to determine the relationship between the difference in cuff area and airway area with the minimum cuff pressure to avoid airway leakage. Adult patients who underwent mechanical ventilation were assigned into three groups, with a minimum cuff pressure of < 20, 20-30, and > 30 cmH2O, respectively, in order to have adequate airway sealing. The primary outcome was the difference between the endotracheal tube cuff area and airway area (cuff-airway area difference) that was calculated for the three groups. A total of 284 patients were included, with the mean age of 65.19 (± 14.03) years old. There were 166, 63 and 55 patients who required a minimum cuff pressure of < 20, 20-30 and > 30 cmH2O, respectively. The mean cuff-airway area difference was 236.00 ± 85.26, 149.70 ± 48.34 and - 12.29 ± 113.0 mm2 in the < 20, 20-30, and > 30 cmH2O groups, respectively. In addition, the simple linear regression analysis revealed a negative linear relationship between the cuff-airway area difference and minimum cuff pressure (Y = -0.1266 × X + 46.50, F = 571.40, p < 0.001). It can be concluded that a significant number of patients require a cuff pressure out of the recommended range (< 20 or > 30 mmH2O) to have adequate airway sealing. Patients with a lower cuff-airway area difference require a higher minimum cuff pressure to seal the airway.

Reevaluating 30 cmH2O endotracheal tube cuff pressure: risks of airway mucosal damage during prolonged mechanical ventilation

Background

The optimal endotracheal tube (ETT) cuff pressure remains contentious. In the traditional consideration that the level 30 cmH2O is considered safe, balancing the prevention of reflux aspiration against airway mucosal damage. Whether this pressure level can cause potential damage to the airway mucosa remains to be discussed.

Methods

Airway mucosa damage and structural changes at 30 cmH2O were examined in patients under general anesthesia and in rabbit mechanical ventilation models. Prior to this, we also interviewed some anesthesiologists about the level of concern about ETT cuff pressure.

Results

A total of 634 valid questionnaires suggested that anesthesiologists generally do not pay enough attention to ETT cuff pressure and the average established cuff pressure significantly exceeded 30 cmH2O. Airway mucosa images of 100 general anesthesia patients with different ventilation duration indicated that maintaining the pressure at 30 cmH2O did not cause significant damage to airway mucosa in a short period of time, while it still caused damage to airway mucosa in patients with long-term ventilation, with damage severity increasing with longer ventilation periods. This correlated strongly with postoperative sore throat (R 2 = 0.3884, p < 0.001). In rabbits, 4 h of ventilation at this pressure resulted in significant loss of ciliated epithelium and inflammation. Calculations suggested an effective dose (ED50) to prevent mucosal injury at a cuff pressure of 25.64 cmH2O (95% CI: 19.268-29.367 cmH2O).

Conclusion

The currently established cuff pressure of 30 cmH2O is associated with airway mucosal damage in both clinical and animal models. Lowering the safety threshold of cuff pressure may be necessary to mitigate mucosal injury.

Problems Related to Endotracheal Intubation as an Input for the Design of a New Endotracheal Tube

Objective

The purpose of the current review is to identify the main problems of endotracheal intubation, which will serve as a basis for the design requirements for a novel endotracheal tube.

Methodology

A PICO systematic search was conducted in PubMed up to December 2021 to identify issues related both to the endotracheal intubation procedure and device-specific factors.

Results

Two primary categories of problems were identified during endotracheal intubation: a) Issues related to laryngotracheal symptoms such as cough, hoarseness, aphonia, dysphonia, dysphagia, swallowing difficulties and the risk of stenosis with long-term intubation. The underlying pressure, abrasion and/or decubitus phenomena should be considered in a new design approach. b) Issues related to the cuff sealing and microaspirations, where the risk of ventilator-associated pneumonia (VAP) highlights the need to improve the design.

Discussion & Conclusion

This review has yielded valuable input for rethinking the design of endotracheal tubes to ensure an efficient and safe airway. This new design should focus on the protection of anatomical structures, avoid or reduce the phenomena of laryngotracheal symptoms, and even reduce the risk of ventilator-associated-pneumonia (VAP) and/or prevent the need for certain tracheostomies.

Effect of different patient positions on endotracheal tube cuff pressure in patients undergoing urological procedures: a prospective study

BACKGROUND

The endotracheal tube (ETT) contains a cuff that is placed in the trachea to prevent gas leakage and aspiration of secretions and gastric contents. However, patient positioning after intubation may cause ETT displacement and changes in cuff pressure.

OBJECTIVES

Evaluate the effect of different patient positions on ETT cuff pressure in patients undergoing urological procedures in supine, prone, lateral flank, and lithotomy positions.

DESIGN

Prospective and observational study.

SETTING

A university hospital in Turkey.

PATIENTS AND METHODS

Patients who underwent surgeries under general anesthesia in different patient positions were involved. After intubation (T0), the cuff pressure was checked with a manometer and adjusted to 25 cmH2O and continuously monitored. The cuff pressure was checked before (T1) and after achieving the final position (T2) and then at 5, (T3), 10, (T4), 15 minutes (T5) of the position, at the end of the procedure (T6) and before extubation (T7). At postoperative 2nd and 12th hours, the patients were interviewed for sore throat, hoarseness, and cough.

MAIN OUTCOME MEASURES

The effect of different patient positions on the ETT cuff pressure.

SAMPLE SİZE

200 patients.

RESULTS

The cuff pressure increased significantly at T2 in the lithotomy, lateral flank, and prone groups (P<.001 each). The highest increase in cuff pressure occurred in the prone group (34.3 [7.5] cmH2O). Over time, the cuff pressure decreased in all groups during surgery. Postoperative complications at the 2nd postoperative hour were similar in all groups; however, the mean cuff pressure was significantly higher in the patients with postoperative sore throat or cough (sore throat: P=.003; cough: P=.047).

CONCLUSION

ETT cuff pressures are affected by different patient positioning; therefore, regular recording and adjustment of cuff pressure are necessary for patient safety.

LIMITATION

We used ETT of a single manufacturer. Therefore, our findings may not be applicable to other types of ETT.

Effect of varying cuff sizes with identical inner diameter on endotracheal intubation in critically ill adults: A sealed tracheal controlled trial

BACKGROUND

The present study aims to determine the impact of different cuff diameters on the cuff pressure of endotracheal tubes (ETTs) when the trachea is adequately sealed.

METHODS

In the present single-center clinical trial, adult patients who underwent cardiothoracic surgery were assigned to use ETTs from 2 brands (GME and GZW). The primary endpoint comprised of the following: cuff diameter, inner diameter of the ETT, manufacturer, and the number of subjects with tracheal leakage when the cuff pressure was 30 cm H2O.

RESULTS

A total of 298 patients were assigned into 2 groups, based on the 2 distinct brands of ETTs: experimental group (n = 122, GME brand) and control group (n = 176, GZW brand). There were no significant differences in baseline characteristics. However, the cuff diameter was significantly smaller in the control group, when compared to the experimental group (P = .001), and the incidence of tracheal leakage was significantly higher in the control group (P = .001). Furthermore, the GME brand ETT had a significantly larger cuff diameter, when compared to the GZW brand ETT.

CONCLUSION

The cuff size would mismatch the tracheal area in clinical practice. Therefore, chest computed tomography is recommended to routinely evaluate the tracheal cross-sectional area during anesthesia, in order to ensure the appropriate cuff size selection.

Risk factor evaluation of cuff pressure of >30 cmH2O to stop air leakage during mechanical ventilation: A prospective observational study

AIM

The commonly recommended endotracheal tube cuff pressure is 20-30 cmH2O. However, some patients require a cuff pressure of >30 cmH2O to prevent air leakage. The study aims to determine the risk factors that contribute to the endotracheal tube cuff pressure of >30 cmH2O to prevent air leakage.

DESIGN

A multi-centre prospective observational study.

METHODS

Eligible patients undergoing mechanical ventilation in the intensive care unit of three hospitals between March 2020 and July 2022 were included. The endotracheal tube cuff pressure to prevent air leakage was determined using the minimal occlusive volume technique. The patient demographics and clinical information were collected.

RESULTS

A total of 284 patients were included. Among these patients, 55 (19.37%) patients required a cuff pressure of >30 cmH2O to prevent air leakage. The multivariate logistic regression results revealed that the surgical operation (odds ratio [OR]: 8.485, 95% confidence interval [CI]: 1.066-67.525, p = 0.043) was inversely associated with the endotracheal tube cuff pressure of >30 cmH2O, while the oral intubation route (OR: 0.127, 95% CI: 0.022-0.750, p = 0.023) and cuff inner diameter minus tracheal area (OR: 0.949, 95% CI: 0.933-0.966, p < 0.001) were negatively associated with the endotracheal tube cuff pressure of >30 cmH2O. Therefore, a significant number of patients require an endotracheal tube cuff pressure of ＞30 cmH2O to prevent air leakage. Several factors, including the surgical operation, intubation route, and difference between the cuff inner diameter and tracheal area at the T3 vertebra, should be considered when determining the appropriate cuff pressure during mechanical ventilation.

Comparison of the effect of pressure control and volume control ventilation on endotracheal tube cuff pressure in patients undergoing general anesthesia and mechanical ventilation: a parallel randomized clinical trial

BACKGROUND

Endotracheal intubation and mechanical ventilation are prevalent interventions in the operating room and intensive care unit. Recently, the complications of endotracheal tube cuff pressure have been a topic of interest. Therefore, this study compared the effect of pressure control and volume control ventilation modes on the endotracheal cuff pressure rate in patients undergoing general anesthesia and mechanical ventilation.

METHODS

In this triple-blinded randomized clinical trial, 50 patients undergoing open limb surgery and inguinal hernia were allocated to two groups of 25 based on inclusion criteria. After intubation, one group underwent ventilation on the pressure control ventilation mode, and the other underwent ventilation on the volume control ventilation mode. In both groups, using a manometer, the cuff's pressure was first adjusted in the range of 25-30 cm of water. Then, the cuff pressure was measured at 10, 20, and 30 min intervals. The data were statistically analyzed using independent t-test, and two-way repeated measures ANOVA.

RESULTS

The present study's findings showed that cuff pressure has significantly decreased over time in both study groups (F = 117.7, P < 0.001). However, a repeated measures ANOVA with a Greenhouse-Geisser correction showed no interaction between time and groups (F = 0.019, P = 0.98). The two groups had no significant difference in cuff pressure (F = 0.56, P = 0.458).

CONCLUSION

Since the cuff pressure has been significantly reduced in both groups over time, continuous monitoring of endotracheal tube cuff pressure in patients undergoing mechanical ventilation is essential. Therefore, it is suggested to keep the cuff pressure within the recommended range to prevent complications resulting from cuff pressure reduction, such as aspiration and ventilation decrease.

TRIAL REGISTRATION

The study was registered in the Iranian Registry of Clinical Trial on 23/02/2019 (trial registration number: IRCT20181018041376N1).

Accuracy of pilot balloon palpation for cuff pressure assessment in small versus large sized tubes: a prospective non-randomized observational study

Pilot balloon palpation is still a commonly used method to evaluate cuff pressure of the endotracheal tube after intubation. This study determined whether the size of the tracheal tube influenced the accuracy of pilot balloon palpation. A prospective observational analysis of 208 patients intubated with an endotracheal tube of internal diameter (ID) 6.0 or 8.0 was conducted. An anesthesiologist judged the cuff pressure by manual pilot balloon palpation, and then measured the cuff pressure with a pressure gauge. Cuff pressure exceeding 20-30 cmH₂O was defined as false recognition. The intracuff pressure was significantly higher in ID 6.0 tube than in the ID 8.0 tube (41.9 ± 18.8 cmH₂O vs. 30.3 ± 11.9 cmH₂O, p < 0.001). The number of patients that were mistakenly perceived to have appropriate cuff pressure by pilot balloon palpation was significantly higher in the ID 6.0 group compared to the ID 8.0 group (85 (81.7%) vs. 64 (61.5%), p = 0.001). Therefore, a smaller tube size may further increase risk of inaccurate measurement by pilot balloon palpation and although pressure gauge is recommended for all sizes to maximize accuracy, groups with increased risk factors should be targeted for standardized use of the pressure gauge.

Disposable Airway Pressure Manometers for Endotracheal Tube Cuff Inflation

This study aimed to assess the performance, accuracy, precision and repeatability of two single-use airway pressure manometers as a cost-effective alternative for inflation of endotracheal tubes with high-volume, low-pressure cuffs. The manometers were tested in a bench top model against a U-tube manometer. Eighteen units of each device were tested. Three consecutive measurements were performed at pressures of 20, 25 and 30 cmH₂O each. The mean ± SD of the recorded pressures and maximum deviation from the target pressures were calculated for each device and each target pressure. For device A, the mean ± SD pressures were 19.6 ± 0.7, 23.6 ± 0.8 and 28.3 ± 0.8 cmH₂O; for device B, the mean ± SD pressures were 19.3 ± 0.6, 24.3 ± 0.9 and 29.2 ± 0.67 cmH₂O for target pressures of 20, 25 and 30 cmH₂O, respectively. The bias for device A was -0.4, -1.4, and -1.7 cmH₂O and for device B, -0.7, -0.7, and -0.8 cmH₂O for target pressures of 20, 25, and 30 cmH₂O, respectively. Both devices showed results comparable to those reported for commercial cuff manometers. They represent inexpensive tools that provide clinically sufficient accuracy, precision and repeatability for ETT cuff inflation between pressures of 20 and 30 cmH₂O.

Effectiveness of Continuous Cuff Pressure Control in Preventing Ventilator-Associated Pneumonia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

Microaspiration of subglottic secretions is the main pathogenic mechanism for ventilator-associated pneumonia (VAP). Adequate inflation of the endotracheal cuff is pivotal to providing an optimal seal of the extraluminal airway. However, cuff pressure substantially fluctuates due to patient or tube movements, which can induce microaspiration. Therefore, devices for continuous cuff pressure control (CCPC) have been developed in recent years. The purpose of this systematic review and meta-analysis is to assess the effectiveness of CCPC in VAP prevention.

DATA SOURCES

A systematic search of Embase, the Cochrane Central Register of Controlled Trials, and the International Clinical Trials Registry Platform was conducted up to February 2022.

STUDY SELECTION

Eligible studies were randomized controlled trials (RCTs) and quasi-RCTs comparing the impact of CCPC versus intermittent cuff pressure control on the occurrence of VAP.

DATA EXTRACTION

Random-effects meta-analysis was used to calculate odds ratio (OR) and 95% CI for VAP incidence between groups. Secondary outcome measures included mortality and duration of mechanical ventilation (MV) and ICU stay. The certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach.

DATA SYNTHESIS

Eleven RCTs with 2,092 adult intubated patients were included. The use of CCPC was associated with a reduced risk of VAP (OR, 0.51). Meta-analyses of secondary endpoints showed no significant difference in mortality but significant differences in durations of MV (mean difference, -1.07 d) and ICU stay (mean difference, -3.41 d) in favor of CCPC. However, the risk of both reporting and individual study bias was considered important. The main issues were the lack of blinding, potential commercial conflicts of interest of study authors and high heterogeneity due to methodological differences between studies, differences in devices used for CCPC and in applied baseline preventive measures. Certainty of the evidence was considered "very low."

CONCLUSIONS

The use of CCPC was associated with a reduction in VAP incidence; however, this was based on very low certainty of evidence due to concerns related to risk of bias and inconsistency.

Efficacy of using an intravenous catheter to repair damaged expansion lines of endotracheal tubes and laryngeal masks

BACKGROUND

In perioperative care or intensive care units, the expansion lines of endotracheal tubes (ETTs) or laryngeal mask airways (LMAs) may be accidentally cut off during medical procedures. We designed a simple method for repairing damaged ETT and LMA expansion lines.

METHODS

In this in vitro study, ETT (n = 20) or LMA (n = 20) models were each categorized into experimental (n = 10) and control (n = 10) groups. In the experimental groups, the expansion lines were cut in the middle, and a 22G intravenous catheter was inserted into the broken end of each expansion line. The time taken to repair the expansion lines was recorded in both experimental groups. The repaired expansion lines in both groups were tested for visible underwater air leakage with cuffs under high pressure (120 cm H2O). After 15 h, the cuff pressure and tensile strength of the expansion lines were measured.

RESULTS

The overall time required to repair the expansion line was 27.8 ± 1.5 s in the ETT group and 20.4 ± 1.1 s in the LMA group. When the cuff pressure was increased to 120 cmH2O, no air leakage was observed in the experimental LMA and ETT groups. The mean difference in the cuff pressures of the control and experimental groups was insignificant for both, ETT (9.50 ± 1.29 vs. 9.50 ± 1.08 cmH2O, 95% CI =  - 1.11 to 1.11 cmH2O, P = 1.00) and LMA (34.1 ± 1.10 cmH2O vs. 34.5 ± 0.97 cmH2O, 95% CI =  - 0.57 to 1.37 cmH2O, P = 0.40) groups, The tensile strength and the force required to pull apart the expansion lines in the experimental groups were lower than those in the control groups for ETTs (3.32 ± 0.37 N vs. 35.03 ± 4.47 N, 95% CI =  - 34.69 to - 28.72 N, P < 0.0001) and LMAs (36.55 ± 2.20 N vs. 26.18 ± 1.67 N, 95% CI =  - 12.21 to - 8.53 N, P < 0.0001).

CONCLUSION

An intravenous catheter can be directly inserted into the damaged ETT or LMA expansion lines; it is a simple, rapid, and effective repair method.

The Relationship between Cuff Pressure and Air Injection Volume of Endotracheal Tube: A Study with Sheep Trachea Ex Vivo

Background

Endotracheal intubation is a widely used treatment. Excessive pressure of the endotracheal tube cuff leads to a series of complications. Here, we used tracheae of sheep to analyze the relationship between the air injection volume and endotracheal tube cuff pressure so as to guide the doctors and nurses in controlling the pressure of the endotracheal tube cuff during clinical work and minimise the risk of complications.

Materials and Methods

Forty sheep tracheae were utilised and were divided into five groups according to their diameters. Different sizes of endotracheal tubes were inserted into each trachea, and the cuff pressure with the increase of air injection volume was recorded. The formulas that reflect the relationship between air injection volume and cuff pressure were obtained. Then, sheep tracheae were randomly selected; different types of tubes were inserted, and the stipulated volume of air was injected. The actual pressure was measured and compared with the pressure predicted from the formulas. Statistical analysis was conducted to verify whether the formulas obtained from the first part of the experiment were in accordance with the expert evaluation table, which consists of opinions of several experts.

Results

After obtaining 15 formulas, we collected the differences between the theoretical cuff pressure and the actual cuff pressure that satisfied the expert evaluation. Relying on the formulas, the medical turntable was obtained, which is a tool that consists of two round cards with data on them. The top card has a notch. The two cards are stacked together, and as the top card rotates, the data on the bottom card can be easily seen in a one-to-one relationship.

Conclusion

The formulas are capable of showing the relationship between the cuff air injection volume and pressure of endotracheal tube cuff. The medical turntable can estimate the air injection volume to ensure that the pressure stays in an acceptable range.

Under- or overpressure: an audit of endotracheal cuff pressure monitoring at the tertiary care center

Background

Mechanical ventilation is a lifesaving intervention for critically ill patients but can produce the major complication of ventilator-associated pneumonia (VAP). Inappropriately inflated endotracheal tubes cause potential harm due to high or low pressure; this can be prevented through monitoring protocols.

Methods

A cross-sectional study of 348 cuff pressure readings was performed with intubated and mechanically ventilated patients to evaluate the exact proportion of patients in intensive care units (ICUs) where the cuff pressure is optimal and to identify the ICUs where device-based monitoring is available to produce a lower proportion of sub-optimal cuff pressure cases. Every three days, cuff pressure was assessed with a handheld cuff pressure manometer. The corresponding VAP rates of those ICUs were obtained from the hospital infection control department.

Results

Cuff pressure of 40.2% was the lower cutoff for the high category, that of optimal was 35.3%, and the highest cutoff of sub-optimal was 24.4%. This study also showed ICUs that had cuff pressure monitoring devices and protocols. Active measurement protocols had a higher proportion of optimal cuff pressure (58.5%) and a lower proportion of sub-optimal and high cuff pressure (19.5% and 22.0%) compared to ICUs with no device-based monitoring protocols. Furthermore, the VAP rate of ICUs exhibited a weak positive correlation with sub-optimal cuff pressure.

Conclusions

Device-based cuff pressure monitoring is essential in maintaining adequate cuff pressure but often is inadequate, resulting in high readings. Therefore, this study suggests that device-based cuff pressure monitoring be practiced.

Could clinical nursing procedures lead to tracheal cuff pressure drop? A prospective observational study

AIM

To evaluate the dynamic changes in tracheal cuff pressure before and after four clinical nursing procedures including sputum suction, oral care, atomisation inhalation, and turning over, and thus provide references for the adjustment time of cuff pressure in clinical practice.

BACKGROUND

Cuff pressure must be kept within the range of 25-30 cmH₂ O to ensure effective ventilation and prevent aspiration, while maintaining tracheal blood flow perfusion.

DESIGN

A prospective observational study.

METHODS

The cuff pressure of 56 intubated patients was adjusted to 28-30 cmH₂ O. A cuff pressure monitor was used to continuously monitor cuff pressure changes before and after four clinical nursing procedures (sputum suction, oral care, atomisation inhalation, and turning over) and the cuff pressures at various time points were compared. The semi-quantitative cough strength score (SCSS) was used to evaluate cough strength during sputum suction and the effect of cough strength on cuff pressure during sputum suction. This study followed the STROBE checklist for cross-sectional studies.

RESULTS

The cuff pressures during the four clinical nursing procedures of sputum suction, atomisation inhalation, turning over, and oral care, all temporarily increased (p < 0.001) and decreased to varying degrees 20 min later (p < 0.001). Among them, the cuff pressure rose the highest under a state of moderate or strong coughing during sputum suction (78.38 ± 12.13 cmH₂ O) and dropped the most at 20 min after the procedure (21.71 ± 4.80 cmH₂ O).

CONCLUSIONS

The four clinical nursing procedures of sputum suction, atomisation inhalation, turning over, and oral care can all cause different degrees of cuff pressure drop. The decision on whether the cuff pressure needs to be corrected depends on the specific situation.

RELEVANCE TO CLINICAL PRACTICE

During clinical practice, the cuff pressure can be individually corrected according to different clinical nursing procedures, which can increase the qualified rate of cuff pressure and reduce the workload of nurses.

The Association Between Endotracheal Tube Size and Aspiration (During Flexible Endoscopic Evaluation of Swallowing) in Acute Respiratory Failure Survivors

OBJECTIVES

To determine whether a modifiable risk factor, endotracheal tube size, is associated with the diagnosis of postextubation aspiration in survivors of acute respiratory failure.

DESIGN

Prospective cohort study.

SETTING

ICUs at four academic tertiary care medical centers.

PATIENTS

Two hundred ten patients who were at least 18 years old, admitted to an ICU, and mechanically ventilated with an endotracheal tube for longer than 48 hours were enrolled.

INTERVENTIONS

Within 72 hours of extubation, all patients received a flexible endoscopic evaluation of swallowing examination that entailed administration of ice, thin liquid, thick liquid, puree, and cracker boluses. Patient demographics, treatment variables, and hospital outcomes were abstracted from the patient's medical records. Endotracheal tube size was independently selected by the patient's treating physicians.

MEASUREMENTS AND MAIN RESULTS

For each flexible endoscopic evaluation of swallowing examination, laryngeal pathology was evaluated, and for each bolus, a Penetration Aspiration Scale score was assigned. Aspiration (Penetration Aspiration Scale score ≥ 6) was further categorized into nonsilent aspiration (Penetration Aspiration Scale score = 6 or 7) and silent aspiration (Penetration Aspiration Scale score = 8). One third of patients (n = 68) aspirated (Penetration Aspiration Scale score ≥ 6) on at least one bolus, 13.6% (n = 29) exhibited silent aspiration, and 23.8% (n = 50) exhibited nonsilent aspiration. In a multivariable analysis, endotracheal tube size (≤ 7.5 vs ≥ 8.0) was significantly associated with patients exhibiting any aspiration (Penetration Aspiration Scale score ≥ 6) (p = 0.016; odds ratio = 2.17; 95% CI 1.14-4.13) and with risk of developing laryngeal granulation tissue (p = 0.02).

CONCLUSIONS

Larger endotracheal tube size was associated with increased risk of aspiration and laryngeal granulation tissue. Using smaller endotracheal tubes may reduce the risk of postextubation aspiration.

Continuous Pneumatic Regulation of Tracheal Cuff Pressure to Decrease Ventilator-associated Pneumonia in Trauma Patients Who Were Mechanically Ventilated: The AGATE Multicenter Randomized Controlled Study

BACKGROUND

Ventilator-associated pneumonia (VAP) is the most frequent health care-associated infection in severely ill patients, and aspiration of contaminated oropharyngeal content around the cuff of the tracheal tube is the main route of contamination.

RESEARCH QUESTION

Is continuous regulation of tracheal cuff pressure using a pneumatic device superior to manual assessment three times daily using a portable manometer (routine care) in preventing VAP in patients with severe trauma?

STUDY DESIGN AND METHODS

In this open-label, randomized controlled superiority trial conducted in 13 French ICUs, adults (age ≥ 18 years) with severe trauma (Injury Severity Score > 15) and requiring invasive mechanical ventilation for ≥ 48 h were enrolled. Patients were randomly assigned (1:1) via a secure Web-based random number generator in permuted blocks of variable sizes to one of two groups according to the method of tracheal cuff pressure control. The primary outcome was the proportion of patients developing VAP within 28 days following the tracheal intubation, as determined by two assessors masked to group assignment, in the modified intention-to-treat population. This study is closed to new participants.

RESULTS

A total of 434 patients were recruited between July 31, 2015, and February 15, 2018, of whom 216 were assigned to the intervention group and 218 to the control group. Seventy-three patients (33.8%) developed at least one episode of VAP within 28 days following the tracheal intubation in the intervention group compared with 64 patients (29.4%) in the control group (adjusted subdistribution hazard ratio, 0.96; 95% CI, 0.76-1.20; P = .71). No serious adverse events related to the use of the pneumatic device were noted.

INTERPRETATION

Continuous regulation of cuff pressure of the tracheal tube using a pneumatic device was not superior to routine care in preventing VAP in patients with severe trauma.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT02534974; URL: www.clinicaltrials.gov.

Continuous Endotracheal Tube Cuff Pressure Control Decreases Incidence of Ventilator-Associated Pneumonia in Patients with Traumatic Brain Injury

BACKGROUND

Ventilator-associated pneumonia (VAP) is a common cause of morbidity and mortality in intensive care unit (ICU), and among the several preventative strategies described to reduce the incidence of VAP, the most important is the endotracheal tube cuff (ETC) pressure. The present study was conducted on 60 patients who required mechanical ventilation (MV) in the ICU with traumatic brain injury (TBI).

METHODS

The patients were randomized into two groups of 30, in which ETC pressure was regulated using a smart cuff manager (SCM) (Group II), or manual measurement approach (MMA) (Group I). Demographic data, MV duration, length of ICU stay and mortality rates were recorded. The clinical pulmonary infection scores (CPISs), C-reactive protein (CRP) values, and the fraction of inspired oxygen (FiO2) and positive end-expiratory pressure (PEEP) values of the groups were compared at baseline, and at hours 48, 72 and 96.

RESULTS

In Group I, CPIS values significantly higher than Group II in 48th, 72nd and 96th hours (p < 0.05). In Group I, PEEP values and deep tracheal aspirate (DTA) culture growth rates significantly higher than Group II in 72nd and 96th hours (p < 0.05).

CONCLUSION

The continuous maintenance of ETC pressure using SCM reduced the incidence of VAP.

Knowledge acquisition and retention among nurses after an educational intervention on endotracheal cuff pressure

BACKGROUND

Nurses play a key role in the proper management of endotracheal tube (ETT) cuff pressure, which is important for patients' safety, so it is vital to improve nurses' knowledge on safe cuff management practices.

AIMS AND OBJECTIVES

This study aimed to evaluate the effectiveness of an educational intervention related to ETT cuff pressure management on improving and retaining critical care nurses' knowledge.

DESIGN

A single group pre-post interventional study was conducted involving 112 registered nurses (RNs) from a 24-bed adult general intensive care unit at a teaching hospital in Malaysia.

METHODS

The educational intervention included a theoretical session on endotracheal cuff pressure management and demonstration plus hands-on practice with the conventional cuff pressure monitoring method. Nurses' knowledge was measured using a self-administered questionnaire pre- and post-intervention. Data were analysed using repeated measure analysis of variance and bivariate analysis.

RESULTS

In this study, 92% of the total number of RNs in the unit participated. A significant difference in mean knowledge score was noted between the pre- (mean = 8.13; SD = 1.53) and post-intervention phases (3 months [mean = 8.97; SD = 1.57) and 9 months post-intervention [mean = 10.34; SD = 1.08), P < .001), indicating significant knowledge acquisition and retention between the phases. Knowledge gained between the pre- and 9 months post-intervention phases significantly differed according to nurses' educational level.

CONCLUSIONS

This study supports existing evidence that ongoing educational interventions are essential to improve nurses' knowledge. However, further exploration is suggested to assess how well this knowledge is translated into clinical practice.

RELEVANCE TO CLINICAL PRACTICE

Regular educational programmes with current updates would enhance nurses' knowledge through proper practice and clinical decision-making skills; this, in turn, would help to standardize cuff management practices.

Clinical assessment of the efficacy of supraglottic airway devices compared with endotracheal tubes in cats during volume-controlled ventilation

The efficacies of a supraglottic airway device (SGAD) and an endotracheal tube (ETT) in cats under general anesthesia with volume-controlled ventilation (VCV) were compared. Thirty healthy cats were randomly allocated for airway control using either an SGAD or an ETT. Five tidal volumes (6, 8, 10, 12, and 14 mL/kg) were randomly tested, and respiratory rates were adjusted to achieve a minute ventilation of 100 mL/kg/min. The dose of propofol necessary to insert the SGAD or ETT, the static respiratory pressure, leakage during VCV, and end tidal CO₂ (ETCO₂) were recorded. Dosages of propofol and static respiratory measurements for the SGAD and ETT groups were compared using a t-test. The distribution of leakages and hypercapnia (ETCO₂ > 45 mmHg) were compared using Fisher's exact test. A significance level of p < 0.05 was established. No significant difference in dose of propofol was observed between the SGAD and ETT groups (7.1 ± 1.0, 7.3 ± 1.7 mg/kg; p = 0.55). Static resistance pressure of the SGAD (22.0 ± 8.1 cmH₂O/L/sec) was significantly lower than that of the ETT (36.6 ± 12.9 cmH₂O/L/sec; p < 0.01). Of the 75 trials, leakage was more frequent when using an SGAD (8 events) than when using an ETT (1 event; p = 0.03). Hypercapnia occurred more frequently with SGAD (18 events) than with ETT (3 events; p < 0.01). Although intubation with an ETT is the gold standard in small animal anesthesia, the use of an SGAD can reduce airway resistance and the work of breathing. Nonetheless, SGAD had more dead space and the tidal volume for VCV needs adjustment.

Automatic regulation of the endotracheal tube cuff pressure with a portable elastomeric device. A randomised controlled study

BACKGROUND

Intermittent manual correction of the endotracheal tube cuff pressure (P_cuff) may delay the detection of underinflation (source of contaminated oropharyngeal content microaspiration) or overinflation (exposing to airway damage). Devices for automated continuous correction of P_cuff are appealing but some are inconvenient, expensive or even harmful. This prospective randomised controlled study tested whether the tracoe Smart Cuff Manager™ reduced the rate of patients undergoing≥1 episode of underinflation (P_cuff<20 cmH₂O), as compared with routine manual P_cuff correction. The rate of patients with≥1 overinflation episode (P_cuff>30 cmH₂O) and the incidence of under/overinflation were also compared.

METHODS

Patients with acute brain injury and likely to receive invasive mechanical ventilation for>48h were randomly allocated to receive, during 48h, automated P_cuff correction (combined with manual correction) or manual correction alone. P_cuff was measured with a dedicated manual manometer, at least every 8h.

RESULTS

Sixty patients were included and randomised (32 patients with manual and 28 with automated P_cuff correction) for 506 measurements of P_cuff (269 and 237, respectively). Automated correction of P_cuff was associated with a lower rate of patients with≥1 episode of underinflation (63% and 18%, respectively, P<0.001), a lower incidence of underinflation episodes (15% vs. 2%; P<0.001), a lower rate of manual corrections (77% vs. 58%; P<0.001). For overinflation, there were no significant between-groups differences (2% vs. 2%). The incidence of early respiratory infections was similar in both groups (29% vs. 25%, P=0.78).

CONCLUSIONS

The adjunction of continuous P_cuff control with the Tracoe Smart Cuff Manager™ to routine manual intermittent correction reduced the incidence of P_cuff underinflation episodes without provoking overinflation.

TRIAL REGISTRATION

ClinicalTrials NCT03330379. Registered 6 November 2017, https://clinicaltrials.gov/ct2/show/NCT03330379.

A mobile terminal application program was used for endotracheal tube cuff pressure measurement

We studied the application of a mobile terminal application program in endotracheal tube (ETT) cuff pressure measurement to improve the implementation rate of scientific ETT cuff pressure measurement and to ensure that the pressure falls within the recommended range. A pre-post controlled study lasting for 18 months was undertaken in a 40-bed general intensive care unit (GICU). This included a 6-month baseline period (baseline group) and a 6-month intervention period (intervention group). The mobile terminal application program was applied to monitor the cuff pressure of endotracheal intubation as an intervention measure during the intervention period. ETT pressure was the main outcome measure, while gender, age, causes for ICU admission, sedation score, duration of prior intubation, size of ETT, and number of VAP patients were secondary outcomes. ETT cuff pressure was monitored 742 times in both the baseline group and the intervention group. A total of 56.9% of the cuff pressure measurements in the baseline group were within the recommended range, while 78.4% of measurements in the intervention group were within the recommended range, reflecting a statistically significant difference (P < 0.05). The application of the mobile terminal application program used for ETT cuff pressure measurement could improve the percentage of ETT cuff pressure measurements falling within the recommended range.

The Changes of Endotracheal Tube Cuff Pressure during Manual and Intermittent Controlling in Intensive Care Units

BACKGROUND

Usually, the endotracheal tube cuff pressure is controlled by cuff pressure monitoring. However, the intermittent pilot-manometer connection and disconnection may cause a change in the adjusted pressure. This study aimed to investigate changes in the endotracheal tube cuff pressure using both manual and intermittent controls.

MATERIALS AND METHODS

A semi-experimental within-subject design was conducted. Fifty-nine intubated patients in the Mazandaran Intensive Care Units (ICUs) participated through convenience sampling in 2018. In the control condition, first, the cuff pressure was adjusted in 25 cm H2O then it was measured without manometer-pilot disconnection at 1 and 5 min intervals. In the intervention condition, cuff pressure was immediately adjusted in 25 cm H2O then it was measured with manometer-pilot disconnection in the 1st and 5th minutes. Data analysis was performed using Independent t-test, Chi-square test, and Phi coefficient.

RESULTS

The mean and Standard Deviation (SD) change of cuff pressure after 1 minute, from 25 cm H2O, in the intervention condition was 20.22 (3.53) cm H2O. The mean (SD) of this change in the control condition was 25.22 (3.39) cm H2O. This difference was significant (t 116 = 7.83, p < 0.001, d = 1.44). The mean (SD) change of cuff pressure after 5 minutes, from 25 cm H2O, in the intervention condition was 19.11 (2.98) cm H2O. The mean (SD) of this change in the control condition was 25.47 (4.53) cm H2O. This difference was significant (t 116 = 9.24, p < 0.001, d = 1.70).

CONCLUSIONS

The tracheal tube cuff pressure has been significantly reduced during manual intermittent measuring. Therefore, it is suggested that continuous cuff pressure monitoring and regulation should be used.

[Subjective method for tracheal tube cuff inflation: performance of anesthesiology residents and staff anesthesiologists. Prospective observational study]

BACKGROUND AND OBJECTIVES

Poor monitoring of tracheal tube cuff pressure may result in patient complications. The objective method of using a manometer is recommended to keep safe cuff pressure values (20-30 cm H₂O). However, as manometers are not readily available, anesthesiologists use subjective methods. We aimed to assess appropriateness of a subjective method for attaining cuff pressure and the expertise level of manometer handling among anesthesiology staff and residents in a university teaching hospital.

METHODS

Prospective observational study, recruiting participants that performed tracheal intubation and the subjective method for tube cuff inflation. Patients with difficult airway, larynx and trachea anatomic abnormality and emergency procedures were not included. Up to 60 minutes after tracheal intubation, an investigator registered the cuff pressure using an aneroid manometer (AMBU®) connected to the tube pilot balloon.

RESULTS

Forty-seven anesthesiologists were included in the study - 24 residents and 23 staff. Mean (SD) and medians (IQR) measured in cm H₂O were, respectively, 52.5 (27.1) and 50 (30-70). We registered 83% of measurements outside the recommended pressure range, with no difference between specialists and residents. The level of expertise with the objective method was also similar in both groups. Pressure adjustments were performed in 76.6% of cases.

CONCLUSION

The subjective method for inflating the tracheal tube cuff resulted in a high rate of inadequate cuff pressures, with no difference in performance between anesthesiology specialists and residents.

Subjective method for tracheal tube cuff inflation: performance of anesthesiology residents and staff anesthesiologists. Prospective observational study

Background and objectives

Poor monitoring of tracheal tube cuff pressure may result in patient complications. The objective method of using a manometer is recommended to keep safe cuff pressure values (20‒30 cm H₂O). However, as manometers are not readily available, anesthesiologists use subjective methods. We aimed to assess appropriateness of a subjective method for attaining cuff pressure and the expertise level of manometer handling among anesthesiology staff and residents in a university teaching hospital.

Methods

Prospective observational study, recruiting participants that performed tracheal intubation and the subjective method for tube cuff inflation. Patients with difficult airway, larynx and trachea anatomic abnormality and emergency procedures were not included. Up to 60 minutes after tracheal intubation, an investigator registered the cuff pressure using an aneroid manometer (AMBU®) connected to the tube pilot balloon.

Results

Forty-seven anesthesiologists were included in the study – 24 residents and 23 staff. Mean (SD) and medians (IQR) measured in cmH₂O were, respectively, 52.5 (27.1) and 50 (30‒70). We registered 83% of measurements outside the recommended pressure range, with no difference between specialists and residents. The level of expertise with the objective method was also similar in both groups. Pressure adjustments were performed in 76.6% of cases.

Conclusion

The subjective method for inflating the tracheal tube cuff resulted in a high rate of inadequate cuff pressures, with no difference in performance between anesthesiology specialists and residents.

Association between core body temperature and mean airway pressure with endotracheal cuff pressure in intubated patients of emergency department

Background & Objective:

Endotracheal intubation is routinely performed in the critical situations. In order to prevent microaspiration and tracheal injury endotracheal cuff pressure is important to remain constant between 20 and 30 cmH₂O. Positive pressure ventilation, duration of intubation, body temperature, and body movements can alter endotracheal cuff pressure. This survey was conducted to evaluate core body temperature and cuff pressure relation with airway pressure simultaneously.

Methods:

This was a descriptive analytic study conducted from March 2018 to July 2018 on 150 intubated patients in the emergency department. All were ventilated with SIMV mode and had Ramsi sedation level of 2-3. Mean airway pressure was measured simultaneouly with core body temperature measurement from ventilator monitor. All these parameters were measured 10 times each hour and documented.

Results:

There was a statistically meaningful relation between airway pressure and cuff pressure in the primary evaluation (P=0.02, r=0.19), while none of the subsequent evaluations showed meaningful relation (P>0.05). No significant relation was found between cuff pressure and core body temperature in any of the measurements (P>0.05).

Conclusion:

The pressure of cuff should be checked repeatedly after intubation because of substantial variation over time. Factors other than core body temperature and airway pressure can influence cuff pressure.

Airway Devices in Ventilator-Associated Pneumonia Pathogenesis and Prevention

Airway devices play a major role in the pathogenesis of microaspiration of contaminated oropharyngeal and gastric secretions, tracheobronchial colonization, and ventilator-associated pneumonia (VAP) occurrence. Subglottic secretion drainage is an effective measure for VAP prevention, and no routine change of ventilator circuit. Continuous control of cuff pressure, silver-coated tracheal tubes, low-volume low-pressure tracheal tubes, and the mucus shaver are promising devices that should be further evaluated by large randomized controlled trials. Polyurethane-cuffed, conical-shaped cuff, and closed tracheal suctioning system are not effective and should not be used for VAP prevention.

An in-vitro study to evaluate high-volume low-pressure endotracheal tube cuff deflation dynamics

BACKGROUND

High-volume low-pressure (HVLP) endotracheal tube (ETT) cuffs for critically ill patients often deflate during the course of mechanical ventilation. We performed an in-vitro study to comprehensively assess HVLP cuff deflation dynamics and potential preventive measures.

METHODS

We evaluated 24-hour deflation of seven HVLP cuffs of cylindrical or tapered shape, and made of polyvinylchloride or polyurethane. Experiments were performed within a thermostated chamber set at 37 °C. In the first stage of experiments, the cuff pilot balloon valve was not manipulated. The cuff internal pressure was assessed hourly for 24 hours, via a linear position sensor which monitored cuff deflation displacements. Then, we re-evaluated cuff deflation of the worst-performing ETT cuffs with the cuff pilot balloon valve sealed. Finally, we inflated ETT cuffs within an artificial trachea to evaluate deflation dynamics during mechanical ventilation.

RESULTS

Initial tests showed an exponential decrease in cuff internal pressure in five out of seven cuffs. Cuffs of cylindrical shape and made of polyurethane demonstrated the fastest deflation rates (P<0.050 vs. cuffs of conical shape and made of polyvinylchloride). When the cuff pilot balloon valve was not sealed, the internal cuff pressure deflation rate differed significantly among ETTs (P=0.005). Yet, upon sealing the cuff pilot balloon valve and during mechanical ventilation, cuff deflation rates decreased (P<0.050).

CONCLUSIONS

In controlled in-vitro settings, ETT cuffs consistently deflate over time, and the cuff pilot balloon valve plays a central role in this occurrence. Deflation rate decreases when cuffs are inflated within a plastic artificial tracheal model and mechanical ventilation is activated.

Is continuous better than intermittent control of tracheal cuff pressure? A meta-analysis

AIM

To compare and evaluate the efficacy and safety of continuous and intermittent control of cuff pressure.

METHODS

We performed a comprehensive and systematic meta-analysis of randomized controlled trials (RCTs) assessing the continuous and intermittent control of P_cuff by searching PUBMED, EMBASE and other such databases (from inception to 31 March 2018). Summary odds ratios or mean differences with 95% confidence intervals were calculated using a fixed- or random-effects model.

MEASUREMENTS AND MAIN RESULTS

Seven randomised controlled trials with 970 mechanically ventilated patients were included in this study. The continuous control of cuff pressure significantly reduced the incidence of cuff pressure < 20 cm H₂ O (0.03 (OR) (95% CI: 0.01-0.07)), P_cuff > 30 cm H₂ O (0.06 (95% CI: 0.03-0.15)) and VAP (0.39 (95% CI: 0.28-0.55)) when compared with intermittent control of cuff pressure. No significant differences in duration of MV (-1.94 (95% CI: -4.06 to -0.17)), length of ICU stay (-3.88 (95% CI: -9.00 to -1.23)) and mortality (0.99 (95% CI: 0.73-1.35)) were found between the two groups.

CONCLUSIONS

Continuous control of cuff pressure offers more benefits in stabilizing the cuff pressure and reducing the incidence of VAP, and more studies are warranted to further evaluate the role of continuous control of cuff pressure.

RELEVANCE TO PRACTICE

The continuous control of cuff pressure should be conducted whenever possible as it is the most ideal for the prognosis of MV patients.

A retrospective observational study of acquired subglottic stenosis using low-pressure, high-volume cuffed endotracheal tubes

INTRODUCTION

The safety of cuffed endotracheal tubes in the neonatal and critically ill pediatric population continues to be questioned due to the theoretical risk of acquired subglottic stenosis. The incidence of acquired subglottic stenosis in the high-risk mixed surgical and medical critically ill pediatric cohort using high-volume, low-pressure cuffed endotracheal tube policy has not yet been described. The aim of our study was to describe and evaluate the use and complication rate of cuffed ETT's in our unit over a 5-year period.

METHODS

We defined clinically significant subglottic stenosis as a positive stenotic finding of endotracheal tube-related pathology on a microlaryngoscopy within 6 months of invasive ventilation. All patients admitted through our pediatric critical care unit from January 10, 2012 to January 25, 2017 were matched against our theater management system database for the same period. We reviewed all matching patients' baseline demographics, comorbidities, intubation/endotracheal tube history, and subsequent surgical management.

RESULTS

Of 5309 pediatric critical care unit admissions (61% ventilated) and 1251 microlaryngoscopies, 23 children had endoscopic findings of clinically significant endotracheal tube-related pathology, reflecting 0.68% of all intubated patients. Eight patients developed acquired subglottic stenosis. All those requiring major surgical correction were ex-premature neonates initially intubated with uncuffed tubes in an external neonatal intensive care. No patient initially intubated with a cuffed endotracheal tube developed subglottic stenosis requiring surgical correction.

CONCLUSION

We report no single case of acquired subglottic stenosis in our cohort that required major surgical correction from a cuffed endotracheal tube during a 5-year period. The introduction of a policy of appropriate placement and maintenance of low-pressure, high-volume cuffed endotracheal tubes in the pediatric critical care unit was not associated with an increased rate of endotracheal tube-related subglottic trauma.

Changes in endotracheal tube intracuff pressure and air leak pressure over time in anesthetized Beagle dogs

OBJECTIVE

To evaluate endotracheal tube intracuff pressure (P_cuff) changes over time and the effect of these changes on air leak pressure (P_leak).

STUDY DESIGN

Prospective experimental study.

ANIMALS

A group of nine healthy adult Beagle dogs.

METHODS

In part I, in vitro measurements of P_cuff were recorded for 1 hour in eight endotracheal tubes subjected to four treatments: room temperature without lubricant (RT0L), room temperature with lubricant (RTWL), body temperature without lubricant (BT0L), and body temperature with lubricant (BTWL). In part II, nine dogs were endotracheally intubated and P_leak was evaluated at P_cuff of 25 mmHg. Subsequently, P_cuff was reset to 25 mmHg (baseline) and P_cuff measurements were recorded every 5 minutes for 1 hour. Subsequently, a second P_leak measurement was recorded at the current P_cuff. The data were analyzed using Wilcoxon signed-rank test, repeated measures anova and Mann-Whitney U test.

RESULTS

In part I, P_cuff differed significantly between the RT0L and RTWL treatments at 5-60 minutes, and between the BT0L and BTWL treatments at 5-35, 55 and 60 minutes (p < 0.05). In part II, compared with baseline pressures, mean P_cuff decreased to <18 mmHg at 10 minutes and significant decreases were recorded at 15-60 minutes (P_cuff range: 10.0 ± 4.9 to 13.4 ± 6.3 mmHg, mean ± standard deviation). Significant differences were observed between the first and second P_leak measurements (p = 0.034). P_leak decreased in six of nine dogs, was not changed in two dogs and increased in one dog.

CONCLUSIONS AND CLINICAL RELEVANCE

Significant decreases in P_cuff over time were measured. P_leak may decrease during anesthesia and increase the risk for silent pulmonary aspiration. The results indicate the need for testing P_cuff more than once, especially at 10 minutes after the onset of anesthesia.

Modification of Tracheal Cuff Shape and Continuous Cuff Pressure Control to Prevent Microaspiration in an Ex Vivo Pig Tracheal Two-Lung Model

OBJECTIVES

Microaspiration of subglottic secretions plays a pivotal role in ventilator-associated pneumonia. Impact of endotracheal tube cuff material and shape on tracheal sealing performance remains debated. The primary objective was to compare the tracheal sealing performance of polyvinyl chloride tapered, cylindrical and spherical cuffs. Secondary objectives were to determine the impact of continuous cuff pressure control on sealing performance and pressure variability.

DESIGN

Prospective randomized ex vivo animal study.

SETTING

French research laboratory.

SUBJECTS

Seventy-two ex vivo pig tracheal two-lung blocks.

INTERVENTIONS

Blocks were randomly intubated with cylindrical (n = 26), tapered (n = 24), or spherical (n = 22) polyvinyl chloride endotracheal tube cuffs. Two milliliter of methylene blue were instilled above the cuff to quantify microaspirations, and lungs were ventilated for 2 hours. Continuous cuff pressure control was implemented in 33 blocks.

MEASUREMENTS AND MAIN RESULTS

Cuff pressures were continuously recorded, and after 2 hours, a microaspiration score was calculated. Tapered cuffs improved cuff sealing performance compared with spherical cuffs with or without continuous cuff pressure control. Compared with spherical cuffs, tapered cuffs reduced the microaspiration score without and with continuous pressure control by 65% and 72%, respectively. Continuous cuff pressure control did not impact sealing performance. Tapered cuffs generated higher cuff pressures and increased the time spent with overinflation compared with spherical cuffs (median [interquartile range], 77.9% [0-99.8] vs. 0% [0-0.5]; p = 0.03). Continuous cuff pressure control reduced the variability of tapered and spherical cuffs likewise the time spent with overinflation of tapered and cylindrical cuffs.

CONCLUSIONS

Polyvinyl chloride tapered cuffs sealing enhanced performance at the cost of an increase in cuff pressure and in time spent with overinflation. Continuous cuff pressure control reduced the variability and normalized cuff pressures without impacting sealing performance.

Multitargeted Feeding Strategies Improve Nutrition Outcome and Are Associated With Reduced Pneumonia in a Level 1 Trauma Intensive Care Unit

BACKGROUND

Factors impeding delivery of adequate enteral nutrition (EN) to trauma patients include delayed EN initiation, frequent surgeries and procedures, and postoperative ileus. We employed 3 feeding strategies to optimize EN delivery: (1) early EN initiation, (2) preoperative no nil per os feeding protocol, and (3) a catch-up feeding protocol. This study compared nutrition adequacy and clinical outcomes before and after implementation of these feeding strategies.

METHODS

All trauma patients aged ≥18 years requiring mechanical ventilation for ≥7 days and receiving EN were included. Patients who sustained nonsurvivable injuries, received parenteral nutrition, or were readmitted to the intensive care unit (ICU) were excluded. EN data were collected until patients received an oral diet or were discharged from the ICU. The improvement was quantified by comparing nutrition adequacy and outcomes between April 2014-May 2015 (intervention) and May 2012-June 2013 (baseline).

RESULTS

The intervention group (n = 118) received significantly more calories (94% vs 75%, P < .001) and protein (104% vs 74%, P < .001) than the baseline group (n = 121). The percentage of patients receiving EN within 24 and 48 hours of ICU admission increased from 41% to 70% and from 79% to 96% respectively after intervention (P < .001). Although there were fewer 28-ay ventilator-free days in the intervention group than in the baseline group (12 vs 16 days, P = .03), receipt of the intervention was associated with a significant reduction in pneumonia (odds ratio, 0.53; 95% confidence interval, 0.31-0.89; P = .017) after adjusting sex and Injury Severity Score.

CONCLUSIONS

Implementation of multitargeted feeding strategies resulted in a significant increase in nutrition adequacy and a significant reduction in pneumonia.

Structural Integrity of a Simple Method to Repair Disrupted Tracheal Tube Pilot Balloon Assemblies

BACKGROUND

An intact pilot balloon assembly is crucial to the proper function of a cuffed tracheal tube. Disruption of the pilot balloon, transection of the inflation line, or valve incompetence results in cuff deflation, which may lead to inadequate ventilation and aspiration of secretions. Such failures typically result in tracheal tube replacement, but this may be a safety risk if a difficult reintubation is anticipated. We recently encountered such a patient who remained intubated postoperatively and in whom the inflation line was transected, causing a large leak. We describe a method to reconstitute the inflation line and report on the structural integrity of the repair. We hypothesized that the repaired assembly would maintain cuff pressure not statistically different from an intact device, but that the inflation line would be weaker.

METHODS

The distal (tapered) portion of a 22-gauge intravenous (IV) catheter was partially inserted into the severed end of the inflation line. A new pilot balloon was cut from an intact tracheal tube with the tubing attached, the end of which had been dilated using a 22-gauge IV catheter. The new tubing was then guided over the protruding portion of the catheter, creating an internal stent. We measured the drop in cuff pressure after 8 hours in an artificial trachea for repaired and intact tracheal tubes. We tested the integrity of the repaired segments, underwater, to high-pressure inflation. We measured the static tensile strength of the inflation line from intact and repaired tracheal tubes. Data are presented as the mean ± standard error. Differences were assessed using the unpaired, 2-sided Student t test, with P < .05 required to claim statistical significance.

RESULTS

Eight-hour interval measurements in 10 intact versus 10 repaired tracheal tubes demonstrated no significant difference in pressure drop (mean difference = 0.5 cm H2O; 95% confidence interval, -2.2 to 1.2 cm H2O; P = .54). There was no visible air leak from 10 repaired inflation line segments when the cuff was inflated to 120 mm Hg. The force needed to break the repaired inflation line was lower than for the intact tubing (n = 7 of each; mean difference = -21.9 N; 95% confidence interval, -25.7 to -18.1 N; P < 10). Repairs to tracheal tubes from various manufacturers with inner diameters ranging from 3.0 to 8.0 mm were successful.

CONCLUSIONS

Repairing a disrupted pilot balloon assembly using an IV catheter as a stent inside the inflation line is an effective temporizing measure in situations where ventilation is impaired and where tracheal tube replacement may present an excessive patient risk.

Does objective measurement of tracheal tube cuff pressures minimise adverse effects and maintain accurate cuff pressures? A systematic review and meta-analysis

Correct inflation pressures of the tracheal cuff are recommended to ensure adequate ventilation and prevent aspiration and adverse events. However there are conflicting views on which measurement to employ. The aim of this review was to examine whether adjustment of cuff pressure guided by objective measurement, compared with subjective measurement or observation of the pressure value alone, was able to prevent patient-related adverse effects and maintain accurate cuff pressures. A search of PubMed, Web of Science, Embase, CINAHL and ScienceDirect was conducted using keywords 'cuff pressure' and 'measure*' and related synonyms. Included studies were randomised or pseudo-randomised controlled trials investigating mechanically ventilated patients both in the intensive care unit and during surgery. Outcomes included adverse effects and the comparison of pressure measurements. Pooled analyses were performed to calculate risk ratios, effect sizes and 95% confidence intervals. Meta-analysis found preliminary evidence that adjustment of cuff pressure guided by objective measurement as compared with subjective measurement or observation of the pressure value alone, has benefit in preventing adverse effects. These included cough at two hours (odds ratio [OR] 0.42, confidence interval [CI] 0.23 to 0.79, P=0.007), hoarseness at 24 hours (OR 0.49, CI 0.31 to 0.76, P <0.002), sore throat (OR 0.73, CI 0.54 to 0.97, P <0.03), lesions of the trachea and incidences of silent aspiration (P=0.001), as well as maintaining accurate cuff pressures (Hedges' g 1.61, CI 2.69 to 0.53, P=0.003). Subjective measurement to guide adjustment or observation of the pressure value alone may lead to patient-related adverse effects and inaccuracies. It is recommended that an objective form of measurement be used.

Automated control of endotracheal tube cuff pressure during simulated flight

BACKGROUND

Successful mechanical ventilation requires that the airway be controlled by an endotracheal tube (ETT) with an inflatable cuff to seal the airway. Aeromedical evacuation represents a unique challenge in which to manage ETT cuffs. We evaluated three methods of automatic ETT cuff pressure adjustment during changes in altitude in an altitude chamber.

METHODS

Size 7.5 and 8.0 mm ETTs that are currently included in the Critical Care Air Transport Team allowance standard were used for the evaluation. Three automatic cuff pressure controllers-Intellicuff, Hamilton Medical; Pyton, ARM Medical; and Cuff Sentry, Outcome Solutions-were used to manage cuff pressures. The fourth group had cuff pressure set at sea level without further adjustment. Each ETT was inserted into a tracheal model and taken to 8,000 feet and then to 16,000 feet at 2,500 ft/min. Baseline cuff pressure at sea level was approximately 25 cm H2O.

RESULTS

Mean cuff pressure at both altitudes with both size ETTs was as follows: Control arm, 141 ± 64 cm H2O; Pyton, 25 ± 0.8 cm H2O; Cuff Sentry, 22 ± 0.3 cm H2O; and Intellicuff, 29 ± 6.6 cm H2O. The mean time that cuff pressure was >30 cm H2O using Intellicuff at both altitudes was 2.8 ± 0.8 minutes. Pressure differences from baseline in the control arm and with Intellicuff were statistically significant. Cuff pressure with the Cuff Sentry tended to be lower than indicated on the device.

CONCLUSIONS

Mean cuff pressures were within the recommended range with all three devices. Intellicuff had difficulty regulating the cuff pressure initially with increases in altitude but was able to reduce the pressure to a safe level during the stabilization period at each altitude. The Pyton and Cuff Sentry allowed the least variation in pressure throughout the evaluation, although the Cuff Sentry set pressure was less than the actual pressure.

LEVEL OF EVIDENCE

Therapeutic study, level V.

CO2 driven endotracheal tube cuff control in critically ill patients: A randomized controlled study

Background

To determine the safety and clinical efficacy of an innovative integrated airway system (AnapnoGuard^™ 100 system) that continuously monitors and controls the cuff pressure (P_cuff), while facilitating the aspiration of subglottic secretions (SS).

Methods

This was a prospective, single centre, open-label, randomized, controlled feasibility and safety trial. The primary endpoint of the study was the rate of device related adverse events (AE) and serious AE (SAE) as a result of using AnapnoGuard (AG) 100 during mechanical ventilation. Secondary endpoints were: (1) mechanical complications rate (2) ICU staff satisfaction; (3) VAP occurrence; (4) length of mechanical ventilation; (5) length of Intensive Care Unit stay and mortality; (6) volume of evacuated subglottic secretions.

Sixty patients were randomized to be intubated with the AG endotracheal-tube (ETT) and connected to the AG 100 system allowing P_cuff adjustment and SS aspiration; or with an ETT combined with SS drainage and P_cuff controlled manually.

Results

No difference in adverse events rate was identified between the groups. The use of AG system was associated with a significantly higher incidence of P_cuff determinations in the safety range (97.3% vs. 71%; p<0.01) and a trend to a greater volume of aspirated SS secretions: (192.0[64–413] ml vs. 150[50–200], p = 0.19 (total)); (57.8[20–88.7] ml vs. 50[18.7–62] ml, p = 0.11 (daily)). No inter-group difference was detected using AG system vs. controls in terms of post-extubation throat pain level (0 [0–2] vs. 0 [0–3]; p = 0.7), hoarseness (42.9% vs. 75%; p = 0.55) and tracheal mucosa oedema (16.7% vs. 10%; p = 0.65).

Patients enrolled in the AG group had a trend to reduced VAP risk of ventilator-associated pneumonia(VAP) (14.8% vs. 40%; p = 0.06), which were more frequently monomicrobial (25% vs. 70%; p = 0.03).

No statistically significant difference was observed in duration of mechanical ventilation, ICU stay, and mortality.

Conclusions

The use AG 100 system and AG tube in critically ill intubated patients is safe and effective in P_cuff control and SS drainage. Its protective role against VAP needs to be confirmed in a larger randomized trial.

Trial registration

ClinicalTrials.gov NCT01550978. Date of registration: February 21, 2012.

A canine model of tracheal stenosis induced by cuffed endotracheal intubation

Postintubation tracheal stenosis is a complication of endotracheal intubation. The pathological mechanism and risk factors for endotracheal intubation-induced tracheal stenosis remain not fully understood. We aimed to establish an animal model and to investigate risk factors for postintubation tracheal stenosis. Beagles were intubated with 4 sized tubes (internal diameter 6.5 to 8.0 mm) and cuff pressures of 100 to 200 mmHg for 24 hr. The status of tracheal wall was evaluated by bronchoscopic and histological examinations. The model was successfully established by cuffed endotracheal intubation using an 8.0 mm tube and an intra-cuff pressure of 200 mmHg for 24 hr. When the intra-cuff pressures were kept constant, a larger sized tube would induce a larger tracheal wall pressure and more severe injury to the tracheal wall. The degree of tracheal stenosis ranged from 78% to 91% at 2 weeks postextubation. Histological examination demonstrated submucosal infiltration of inflammatory cells, hyperplasia of granulation tissue and collapse of tracheal cartilage. In summary, a novel animal model of tracheal stenosis was established by cuffed endotracheal intubation, whose histopathological feathers are similar to those of clinical cases of postintubation tracheal stenosis. Excessive cuff pressure and over-sized tube are the risk factors for postintubation tracheal stenosis.

The effect of mouth prop on endotracheal tube intracuff pressure in children during dental rehabilitation under general anaesthesia

Although the endotracheal tube (ETT) cuff may be associated with tracheal morbidity, cuffed tubes may reduce the aspiration risk in oral procedures. Dentists must use a mouth prop to facilitate oral visualization and to protect the oral soft tissues during dental rehabilitation under general anaesthesia (DRGA). The aim of this study was to evaluate the effect of mouth prop on endotracheal tube intracuff pressure in children during DRGA. Two-hundred and three ASA I-II patients, <18 years of age (mean: 5.3 ± 2.4 years) were included in the prospective observational study whose comprehensive dental treatment was performed under general anaesthesia. Following the induction of general anaesthesia, placement of a cuffed endotracheal tube which was an appropriate size for children was fixed. The intracuff pressure was measured intermittently after the intubation (baseline) (T0), immediately after the mouth prop (T1), 30 min after the mouth prop (T2), after taking out the mouth prop (T3) and just before extubation (T4). The mean intracuff pressure was 28.3 ± 2.01 cm H₂O at T0. The mean intracuff pressure significantly increased at T1 (30.8 ± 2.7) and T2 (29.6 ± 3.7) compared to T0 (P < 0.001). No significant differences were observed between the duration of the procedure and intracuff pressure or postoperative complications (P > 0.05). Cough, sore throat and nausea were observed in 4, 1 and 5 patients, respectively. Because a mouth prop may increase the intracuff pressure of ETT, strict measurement and readjustment of cuff pressures should be employed when used in children during DRGA.

Efficiency of an electronic device in controlling tracheal cuff pressure in critically ill patients: a randomized controlled crossover study

BACKGROUND

Despite intermittent control of tracheal cuff pressure (P _cuff) using a manual manometer, cuff underinflation (<20 cmH₂O) and overinflation (>30 cmH₂O) frequently occur in intubated critically ill patients, resulting in increased risk of microaspiration and tracheal ischemic lesions. The primary objective of our study was to determine the efficiency of an electronic device in continuously controlling P _cuff. The secondary objective was to determine the impact of this device on the occurrence of microaspiration of gastric or oropharyngeal secretions.

METHODS

Eighteen patients requiring mechanical ventilation were included in this prospective randomized controlled crossover study. They randomly received either continuous control of P _cuff with Mallinckrodt^® device for 24 h, followed by discontinuous control with a manual manometer for 24 h, or the reverse sequence. During the 48 h after randomization, P _cuff was continuously recorded, and pepsin and alpha amylase were quantitatively measured in tracheal aspirates. P _cuff target was 25 cmH₂O.

RESULTS

Clinical characteristics were similar during the two study periods, as well as mean airway pressure. Percentage of time spent with cuff overinflation or underinflation was significantly lower during continuous control compared with routine care period [median (IQR) 0.8 (0.1, 2) vs 20.9 (3.1, 40.1), p = 0.0009]. No significant difference was found in pepsin [median (IQR) 230 (151, 300) vs 259 (134, 368), p = 0.95] or in alpha amylase level [median (IQR) 1475 (528, 10,333) vs 2400 (1342, 15,391), p = 0.19] between continuous control and routine care periods, respectively.

CONCLUSIONS

The electronic device is efficient in controlling P _cuff, compared with routine care using a manometer. Further studies are needed to evaluate the impact of this device on intubation-related complications. Trial registration ClinicalTrials.gov Identifier: NCT01965821.

Measurement of endotracheal tube cuff pressure: Instrumental versus conventional method

Objective:

To evaluate the conventional practice of endotracheal tube (ETT) cuff inflation and pressure measurement as compared to the instrumental method.

Study Design:

Prospective observational study.

Place and Duration of Study:

Department of Anaesthesia, King Saud University Hospital, Riyadh, Saudi Arabia (June 2014–July 2014).

Methods:

A total of 100 adult patients were observed according to the syringe size used Group-1 (10 ml) and Group-2 (20 ml) for ETT cuff inflation in general anesthesia. Patients with anticipated difficult intubation, risk for aspiration, known anatomical laryngotracheal abnormalities, and emergency cases were excluded. Trachea was intubated with size 8 or 8.5 mm and 7.0 or 7.5 mm ETT in male and female patients respectively. The ETT cuff was inflated with air by one of the anesthesia technician. Cuff pressures were measured using aneroid manometer. ETT cuff pressure of 20–30 cm of water was considered as standard.

Results:

In 69% of the patients, the cuff pressure measurements were above the standard. Age (P = 0.806), weight (P = 0.527), height (P = 0.850), and gender (P = 1.00) were comparable in both groups. The mean cuff pressure in Group-1 and Group-2 was 32.52 ± 6.39 and 38.90 ± 6.60 cm of water (P = 0.001). The cuff inflation with 20 ml syringe resulted in higher cuff pressure as compared to 10cc syringe 37.73 ± 4.23 versus 40.74 ± 5.01 (86% vs. 52%, P = 0.013).

Conclusion:

The conventional method for ETT cuff inflation and pressure measuring is unreliable. As a routine instrumental cuff pressure, monitoring is suggested.

Continuous control of tracheal cuff pressure for VAP prevention: a collaborative meta-analysis of individual participant data

Background

Underinflation of tracheal cuff is a risk factor for microaspiration of contaminated secretions and subsequent ventilator-associated pneumonia (VAP). The aim of this collaborative meta-analysis of individual participant data is to determine the impact of continuous control of P_cuff on the incidence of VAP.

Methods

Studies were identified by searching PubMed and references of relevant articles. Data from 3 prospective controlled trials (two randomized and one quasi-randomized), which evaluated the impact of continuous control of P_cuff on the incidence of VAP, were obtained and pooled together. Three different devices were used to continuously control P_cuff. VAP was diagnosed using clinical, radiologic, and quantitative microbiological criteria. The impact of continuous control of P_cuff on VAP was assessed by Cox regression analysis, stratified on trial.

Results

263 (48.4 %) patients received continuous control of P_cuff, and 280 (51.5 %) patients received routine control of P_cuff using a manometer. 36 (13.6 %) VAP were diagnosed in continuous control group, and 72 (25.7 %) in routine care group (HR 0.47, 95 % CI 0.31–0.71, p < 0.001). However, heterogeneity was apparent in continuous control effect size across trials (I² = 58 %, p = 0.085). The number of patients needed to treat to prevent one VAP episode was 8. No significant impact of continuous control of P_cuff was found on duration of mechanical ventilation, ICU length of stay, or mortality.

Conclusion

Continuous control of P_cuff might be beneficial in reducing the risk for VAP. However, no significant impact of continuous control of P_cuff was found on duration of mechanical ventilation, ICU length of stay, or mortality.

Analysis of the incidence of postintubation injuries in patients intubated in the prehospital or early hospital conditions of the hospital emergency department and the intensive care unit

BACKGROUND

Intubation is still one of the best methods to secure the airway. In the case of prehospital or early hospital conditions when factors such as urgency, stress, or inaccuracy of the undertaken activities are involved, the risk of causing complications, for instance, edema or postintubation injuries, increases, especially while dealing with a difficult intubation. The risk of improper inflation of the endotracheal tube cuff also increases, which is considered in this study.

OBJECTIVE

The aim of this study was to evaluate the prevalence of postintubation complications, such as postintubation injuries or edema, in a research sample, and to examine whether such complications occur more often, for example, while using a guidewire. In this study, we also evaluated the injuries associated with the inflation of the endotracheal tube cuff.

MATERIALS AND METHODS

This study was performed on a group of 153 patients intubated in prehospital conditions. The tests were carried out in three clinical sites that received patients from prehospital care. Postintubation injuries were revealed and photographed using videolar-yngoscope, such as the C-MAC and the McGrath series 5. The endotracheal tube cuff pressure was measured using a pressure gage manual (VBM Medizintechnik GmbH). The quantitative analyses of differences between incidence of variables were assessed using χ (2) test for P<0.05. Analyses have been carried out using the Statistica software.

RESULTS

In the group of 153 patients, postintubation injuries occurred in 17% of cases. The dependency between using the guidewire and the occurrence of the hematomas and loss of mucosa was statistically significant (P<0.01). In nearly half (42%) of the patients the endotracheal tube cuff pressure was excessively inflated over 30 cm H2O, and in two cases, endotracheal tube displacement was observed on account of poor cuff inflation (<20 cm H2O).

CONCLUSION

The highest percentage of overfilled cuffs were observed in the admission room. In the other wards, it was observed in 25% of cases. Even though only six cases of poor cuff inflation were noticed, the relationship between the leakage and the clinical conditions of patients is worth examining. The results would help in taking additional measures to reduce the risk of complications.