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

Rebound Inverts the Staphylococcus aureus Bacteremia Prevention Effect of Antibiotic Based Decontamination Interventions in ICU Cohorts with Prolonged Length of Stay

Could rebound explain the paradoxical lack of prevention effect against Staphylococcus aureus blood stream infections (BSIs) with antibiotic-based decontamination intervention (BDI) methods among studies of ICU patients within the literature? Two meta-regression models were applied, each versus the group mean length of stay (LOS). Firstly, the prevention effects against S. aureus BSI [and S. aureus VAP] among 136 studies of antibiotic-BDI versus other interventions were analyzed. Secondly, the S. aureus BSI [and S. aureus VAP] incidence in 268 control and intervention cohorts from studies of antibiotic-BDI versus that among 165 observational cohorts as a benchmark was modelled. In model one, the meta-regression line versus group mean LOS crossed the null, with the antibiotic-BDI prevention effect against S. aureus BSI at mean LOS day 7 (OR 0.45; 0.30 to 0.68) inverted at mean LOS day 20 (OR 1.7; 1.1 to 2.6). In model two, the meta-regression line versus group mean LOS crossed the benchmark line, and the predicted S. aureus BSI incidence for antibiotic-BDI groups was 0.47; 0.09-0.84 percentage points below versus 3.0; 0.12-5.9 above the benchmark in studies with 7 versus 20 days mean LOS, respectively. Rebound within the intervention groups attenuated and inverted the prevention effect of antibiotic-BDI against S. aureus VAP and BSI, respectively. This explains the paradoxical findings.

Pressure changes in the endotracheal tube cuff in otorhinolaryngologic surgery: a prospective observational study

Objective

Inflation of the endotracheal tube cuff is needed for providing ventilation. Cuff pressure should be maintained inside the appropriate range to prevent critical airway complications. The purpose of this study is to evaluate the pressure changes in the endotracheal tube cuff during otorhinolaryngologic surgery.

Design and method

This single-center observational study was conducted at Severance Hospital in Korea between April 2020 and November 2020. Patients aged >20 years scheduled to undergo otorhinolaryngological surgical procedures were enrolled. Patients undergoing planned tracheostomy and those who were slated for uncuffed endotracheal tube use were excluded. Intubation was performed after the induction of general anesthesia. A pressure transducer was connected to the pilot balloon of the endotracheal tube, and cuff pressure was continuously monitored until extubation. If the cuff pressure was not appropriate for more than 5 min, it was adjusted to the appropriate range by injecting or removing air. The percentage of time for which the cuff pressure remained within the appropriate range was calculated and defined as the time in the therapeutic range (TTR). The presumed cause for the rise or fall in cuff pressure was identified.

Results

In total 199 patients, alterations in cuff pressure outside the appropriate range occurred in 191 patients (96.0%). The mean TTR was 79.7% (SD 25.0%), and head and neck surgery had the lowest mean TTR of 69.0% compared to ear and nose surgeries (94.2 and 82.1%, respectively). Sixty-eight patients (34.2%) demonstrated inadequate endotracheal tube cuff pressure for more than 20% of the total anesthesia time. Twenty-six patients (13.1%) demonstrated optimal endotracheal tube cuff pressure for less than 50% of the total anesthesia time. The causative factors inducing inappropriate cuff pressure were found to vary, including positional changes, surgical procedure, anatomical manipulation, and anesthetic procedure.

Conclusion

In otorhinolaryngologic surgery, cuff pressure increased or decreased outside the appropriate range due to various factors. Therefore, we suggest close continuous monitoring of cuff pressure during anesthesia for otorhinolaryngologic surgery.

Clinical trial registration

clinicaltrials.gov, identifier NCT03938493.

Intermittent versus continuous control of tracheal cuff pressure in patients undergoing mechanical ventilation: A systematic review and meta-analysis

AIMS AND OBJECTIVES

To evaluate the effects and safety of intermittent versus continuous control of cuff pressure in patients with mechanical ventilation.

BACKGROUND

Tracheal cuff pressure management is vital to the prognosis of patients with mechanical ventilation.

DESIGN

A meta-analysis.

METHODS

This meta-analysis was conducted and reported according to the PRISMA checklist. We searched Pubmed, Embase, The Cochrane Library, BMJ Best Practice, Web of Science, ProQuest Dissertations, as well as the Chinese Biomedical Literature Database, Wanfang, and China national knowledge infrastructure databases up to 5 August 2022 for randomised controlled trials (RCTs) on the intermittent versus continuous control of cuff pressure. Review Manager 5.3 software was used for relevant data analysis.

RESULTS

A total of 18 RCTs involving 1998 patients with mechanical ventilation were included. The synthesised outcomes indicated that continuous control of cuff pressure is beneficial to reduce the incidence of ventilator-associated pneumonia (VAP) [RR = 0.41, 95%CI (0.35, 0.49)], aspiration [RR = 0.36, 95%CI (0.21, 0.63)], duration of mechanical ventilation [MD = -3.23, 95%CI (-4.66, -1.79)], length of ICU stay [MD = -4.12, 95%CI (-5.40, -2.83)], and increase the volume of subglottic drainage [MD = 18.54, 95%CI (16.50, 20.58)]. There was no significant difference in the mortality between two groups [RR = 1.01, 95%CI (0.84, 1.21)]. Egger regression analyses showed that there were no obvious publication biases in the synthesised results (all p > .05).

CONCLUSIONS

Existing evidence shows that compared with intermittent monitoring of cuff pressure, continuous monitoring of cuff pressure can reduce the occurrence of aspiration and VAP, shorten the patient's duration of mechanical ventilation and length of ICU stay.

RELEVANCE TO CLINICAL PRACTICE

Continuous monitoring of cuff pressure is more beneficial and should be promoted in clinical nursing care of patients undergoing mechanical ventilation.

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.

Effect of modified care bundle for prevention of ventilator-associated pneumonia in critically-ill neurosurgical patients

Background:

Care bundles for ventilator-associated pneumonia (VAP) have been shown to minimize the rate of VAP in critically ill patients. Standard care bundles may need to be modified in resource-constrained situations. The goal of this study was to see if our modified VAP-care bundles lowered the risk of VAP in neurosurgical patients.

Methods:

A prospective cohort study was conducted in mechanically ventilated neurosurgical patients. The VAP bundle was adjusted in the cohort group by increasing the frequency of intermittent endotracheal tube cuff pressure monitoring to six times a day while reducing oral care with 0.12% chlorhexidine to three times a day. The rate of VAP was compared to the historical control group.

Results:

A total of 146 and 145 patients were enrolled in control and cohort groups, respectively. The mean age of patients was 52±16 years in both groups (P=0.803). The admission Glasgow coma scores were 7.79±2.67 and 7.80±2.77 in control and cohort group, respectively (P=0.969). VAP was found in nine patients in control group but only one patient in cohort group. The occurrence rate of VAP was significantly reduced in cohort group compared to control group (0.88/1,000 vs. 6.84/1,000 ventilator days, P=0.036).

Conclusions:

The modified VAP bundle is effective in lowering the VAP rate in critically ill neurosurgical patients. It requires low budget and manpower and can be employed in resource-constrained settings.

Intra-tracheal multiplexed sensing of contact pressure and perfusion

Incorrect endotracheal tube (ETT) cuff inflation pressure causes significant problems for intubated patients. The technical development and first in vivo use of a smart ETT for measurements at the cuff-trachea interface during mechanical ventilation are described. The intra-tracheal multiplexed sensing (iTraXS) ETT contains integrated optical fibre sensors to measure contact pressure and blood perfusion. The device is tested during mechanical ventilation in a porcine model (N=6). For contact pressure, signals were obtained in all 30 measurements. For perfusion, data could be obtained in all 33 measurements. In the 3 cases where the cuff was inflated to an artificially high-level, blood occlusion is observed.

Automatic Continuous Control of Cuff Pressure and Subglottic Secretion Suction Used Together to Prevent Pneumonia in Ventilated Patients-A Retrospective and Prospective Cohort Study

The ventilator bundle consists of multiple methods to reduce ventilator-associated pneumonia (VAP) rates in Intensive Care Units (ICU). The aim of the study was to evaluate how the continuous automatic pressure control in tapered cuffs of endotracheal/tracheostomy tubes applied along with continuous automatic subglottic secretion suction affect the incidence of VAP. In the prospective cohort (n = 198), the standard VAP bundle was modified by continuous automatic pressure control in taper-shaped cuff of endotracheal/tracheostomy tubes and subglottic secretion suction. VAP incidence, time to VAP onset, invasive mechanical ventilation days/free days, length of ICU stay, ICU mortality, and multidrug-resistant bacteria were assessed and compared to the retrospective cohort (n = 173) with the standard bundle (intermittent cuff pressure of standard cuff, lack of subglottic secretion suction). A smaller incidence of VAP (9.6% vs. 19.1%) and early onset VAP (1.5% vs. 8.1%) was found in the prospective compared to the retrospective cohort (p < 0.01). Patients in the prospective cohort were less likely to develop VAP (RR = 0.50; 95% CI: 0.29 to 0.85) and early-onset VAP (RR = 0.19; 95% CI: 0.05 to 0.64) and had longer time to onset VAP (median 9 vs. 5 days; p = 0.03). There was no significant difference (p > 0.05) between both cohorts in terms of invasive mechanical ventilation days/free days, length of ICU stay, ICU mortality and multidrug-resistant bacteria. Modification of the bundle for prevention of VAP can reduce early-onset VAP and total incidence of VAP and delay the time of VAP occurrence.

Effectiveness of continuous endotracheal cuff pressure control for the prevention of ventilator associated respiratory infections: an open-label randomised, controlled trial

Background

An endotracheal tube cuff pressure between 20 and 30 cmH₂O is recommended to prevent ventilator-associated respiratory infection (VARI). We aimed to evaluate whether continuous cuff pressure control (CPC) was associated with reduced VARI incidence compared with intermittent CPC.

Methods

We conducted a multicenter open-label randomized controlled trial in intensive care unit (ICU) patients within 24 hours of intubation in Vietnam. Patients were randomly assigned 1:1 to receive either continuous CPC using an automated electronic device or intermittent CPC using a manually hand-held manometer. The primary endpoint was the occurrence of VARI, evaluated by an independent reviewer blinded to the CPC allocation.

Results

We randomized 600 patients; 597 received the intervention or control and were included in the intention to treat analysis. Compared with intermittent CPC, continuous CPC did not reduce the proportion of patients with at least one episode of VARI (74/296 [25%] vs 69/301 [23%]; odds ratio [OR] 1.13; 95% confidence interval [CI] .77–1.67]. There were no significant differences between continuous and intermittent CPC concerning the proportion of microbiologically confirmed VARI (OR 1.40; 95% CI .94–2.10), the proportion of intubated days without antimicrobials (relative proportion [RP] 0.99; 95% CI .87–1.12), rate of ICU discharge (cause-specific hazard ratio [HR] 0.95; 95% CI .78–1.16), cost of ICU stay (difference in transformed mean [DTM] 0.02; 95% CI −.05 to .08], cost of ICU antimicrobials (DTM 0.02; 95% CI −.25 to .28), cost of hospital stay (DTM 0.02; 95% CI −.04 to .08), and ICU mortality risk (OR 0.96; 95% CI .67–1.38).

Conclusions

Maintaining CPC through an automated electronic device did not reduce VARI incidence.

Clinical Trial Registration

NCT02966392.

Rapid-flow expulsion maneuver in subglottic secretion clearance to prevent ventilator-associated pneumonia: a randomized controlled study

Background

Following endotracheal intubation, clearing secretions above the endotracheal tube cuff decreases the incidence of ventilator-associated pneumonia (VAP); therefore, subglottic secretion drainage (SSD) is widely advocated. Our group developed a novel technique to remove the subglottic secretions, the rapid-flow expulsion maneuver (RFEM). The objective of this study was to explore the effectiveness and safety of RFEM compared with SSD.

Methods

This study was a single-center, prospective, randomized and controlled trial, conducted at Respiratory Intensive Care Unit (ICU) of Beijing Chao-Yang Hospital, a university-affiliated tertiary hospital. The primary outcome was the incidence of VAP, assessed for non-inferiority.

Results

Patients with an endotracheal tube allowing drainage of subglottic secretions (n = 241) were randomly assigned to either the RFEM group (n = 120) or SSD group (n = 121). Eleven patients (9.17%) in the RFEM group and 13 (10.74%) in the SSD group developed VAP (difference, − 1.59; 95% confidence interval [CI] [− 9.20 6.03]), as the upper limit of 95% CI was not greater than the pre-defined non-inferiority limit (10%), RFEM was declared non-inferior to SSD. There were no statistically significant differences in the duration of mechanical ventilation, ICU mortality, or ICU length of stay and costs between groups. In terms of safety, no accidental extubation or maneuver-related barotrauma occurred in the RFEM group. The incidence of post-extubation laryngeal edema and reintubation was similar in both groups.

Conclusions

RFEM is effective and safe, with non-inferiority compared to SSD in terms of the incidence of VAP. RFEM could be an alternative method in first-line treatment of respiratory ICU patients.

Trial registration This study has been registered on ClinicalTrials.gov (Registration Number: NCT02032849, https://clinicaltrials.gov/ct2/show/NCT02032849); registered on January 2014

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00887-5.

Establishing changes in endotracheal cuff pressure with continuous monitoring in patients undergoing laparoscopic surgery in Trende- lenburg position

Background : After endotracheal intubation, the endotracheal cuff gets inflated to a sufficiently high pressure to prevent air leaking. Placing a patient in Trendelenburg position and establishing a pneumoperitoneum affects the endotracheal cuff pressure. Objectives : Determine the impact of these factors on the endotracheal cuff pressure. Design and setting : This prospective, observational study was conducted in the Catharina Hospital (Eindhoven, the Netherlands). Methods : This study included adult patients undergoing laparoscopic surgery. A routine endotracheal tube was inserted, in which the cuff pressure was continuously monitored. Main outcome measures : The outcome of interest was a change in endotracheal cuff pressure after establishment of a pneumoperitoneum and/ or placing a patient in a Trendelenburg position. Results : 39 patients were included. Cuff pressures in- creased significantly from the moment of pneumo-peritoneum, placing a patient into a Trendelenburg position increased endotracheal cuff pressure and peak pressures even more. The highest endotracheal cuff pressure was 67 cm H2O, the highest registered peak pressure was 35 cm H2O. Conclusion : Both endotracheal cuff pressure and peak pressure increased during laparoscopic surgical procedures with a pneumoperitoneum and the patient placed in Trendelenburg position. Measuring the endo-tracheal cuff pressure only after endotracheal intubation is insufficient and should be repeated during surgery on fixed moments.

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.

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.

Endotracheal cuff pressures in the PICU: Incidence of underinflation and overinflation

BACKGROUND

While uncuffed endotracheal tubes have been traditionally used in the pediatric intensive care unit (PICU) population, evidence suggests cuffed endotracheal tubes (ETTs) are also safe to use within this population. Nevertheless, risks related to the use of cuffed ETTs increase when guidelines for safe and appropriate use are not followed. The primary goal of this study was to measure the cuff pressure (CP) using a cuff pressure manometer in a group of intubated pediatric subjects and determine the rate of cuff underinflation (<20 cm H₂0) or overinflation (>30 cm H₂0). The secondary aim was to determine whether CP was associated to gender, age, ETT size, and PICU length of stay prior to CP measurement.

METHODS

This was a prospective observational study conducted in an urban PICU. Pediatric subjects intubated with cuffed ETTs from 1 April 2017 to 1 May 2017 were included in the study. ETT CPs were measured daily to determine degree of inflation and compared according to gender, age, ETT size, and number of days intubated prior to CP measurement. Descriptive data are expressed as means and standard deviations. A two-sample t test was used to compare groups according to age, gender, and number of days present. And significance was considered with a P < 0.05. Pearson chi test was used to evaluate correlation between CPs and size of the ETT, number of days intubated prior to CP measurement, gender, and age.

RESULTS

Twenty pediatric subjects admitted during the study period were included for analysis. Eleven cuff measurements were found to be within normal limits, while 9 cuff measurements were found to be underinflated. No cases of overinflation were found. There were no significant associations between CP and size of the ETT (r = -0.08), number of days intubated prior to CP measurement (r = 0.19), gender (r = 0.09), and age (r = 0.12).

CONCLUSIONS

Our study suggests that endotracheal cuff underinflation occurs often in the PICU population. Strategies to ensure appropriate ETT CPs are maintained are essential in the intubated pediatric population. Additional studies are necessary to develop interventions and training focused on the use of a cuff pressure manometer to measure CPs in the PICU by respiratory therapists and ensure consistent measurement using inter rater evaluation processes are needed.

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.

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.

Endotracheal tube cuff pressure changes during manual cuff pressure control manoeuvres: An in-vitro assessment

BACKGROUND

Endotracheal tube (ETT) cuffs are designed to seal the lower airway for precise ventilation and to protect against ingress of pathogens from the pharyngeal space. Therefore, a minimal continuous cuff pressure must be maintained. Aim of this study was to analyse the course of cuff pressure in an in-vitro model during manual cuff pressure control manoeuvres.

METHODS

An artificial trachea was intubated with an appropriately sized ETT and cuff pressure set to 20 cm H₂ O. Thirty-two experienced ICU nurses each performed six cuff pressure control manoeuvres (three times in two different ETTs) using a manual cuff pressure manometer. Course of cuff pressure from connecting the manometer to disconnecting it from the cuff pilot balloon was recorded using a pressure transducer.

RESULTS

There were 190 cuff pressure control manoeuvres suitable for analysis. In all control manoeuvres a cuff pressure below 20 cm H₂ O was noted. In 20.0% of the control manoeuvres the cuff pressure dropped below 10 cm H₂ O. Cuff pressure drops were mainly caused by initially connecting the manometer to the pilot balloon, less frequently by manipulating the pressure gauge of the manometer. Disconnecting the manometer after the control manoeuvre caused a cuff pressure drop in 78.1% of cases, contributing to a final cuff pressure below 20 cm H₂ O in 31.3% of control manoeuvres.

CONCLUSION

Routine manual cuff pressure control manoeuvres in ETT cuffs result in considerable cuff pressure drops. This may have an impact on silent aspiration of pharyngeal contents passing along the cuff into the lower airway.

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.

Continuous versus intermittent endotracheal cuff pressure control for the prevention of ventilator-associated respiratory infections in Vietnam: study protocol for a randomised controlled trial

BACKGROUND

Ventilator-associated respiratory infection (VARI) comprises ventilator-associated pneumonia (VAP) and ventilator-associated tracheobronchitis (VAT). Although their diagnostic criteria vary, together these are the most common hospital-acquired infections in intensive care units (ICUs) worldwide, responsible for a large proportion of antibiotic use within ICUs. Evidence-based strategies for the prevention of VARI in resource-limited settings are lacking. Preventing the leakage of oropharyngeal secretions into the lung using continuous endotracheal cuff pressure control is a promising strategy. The aim of this study is to investigate the efficacy of automated, continuous endotracheal cuff pressure control in preventing the development of VARI and reducing antibiotic use in ICUs in Vietnam.

METHODS/DESIGN

This is an open-label randomised controlled multicentre trial. We will enrol 600 adult patients intubated for ≤ 24 h at the time of enrolment. Eligible patients will be stratified according to admission diagnosis (180 tetanus, 420 non-tetanus) and site and will be randomised in a 1:1 ratio to receive either (1) automated, continuous control of endotracheal cuff pressure or (2) intermittent measurement and control of endotracheal cuff pressure using a manual cuff pressure meter. The primary outcome is the occurrence of VARI, defined as either VAP or VAT during the ICU admission up to a maximum of 90 days after randomisation. Patients in both groups who are at risk for VARI will receive a standardised battery of investigations if their treating physician feels a new infection has occurred, the results of which will be used by an endpoint review committee, blinded to the allocated arm and independent of patient care, to determine the primary outcome. All enrolled patients will be followed for mortality and endotracheal tube cuff-related complications at 28 days and 90 days after randomisation. Other secondary outcomes include antibiotic use; days ventilated, in ICU and in hospital; inpatient mortality; costs of antibiotics in ICU; duration of ICU stay; and duration of hospital stay.

DISCUSSION

This study will provide high-quality evidence concerning the use of continuous endotracheal cuff pressure control as a method to reduce VARI, antibiotic use and hospitalisation costs and to shorten stay.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02966392 . Registered on November 9, 2016. Protocol version: 2.0; issue date March 3, 2017.

Orotracheal tube as a risk factor for lower respiratory tract infection: preliminary data from a randomised trial

PURPOSE

The aim of the study was to investigate whether polyurethane (PU) endotracheal tubes, continuous measurements of cuff pressure and aspiration of the subglottic space as a bundle of parameters could reduce patients' risk for developing ventilator associated pneumonia (VAP).

METHODS

Two groups of patients that differed only in terms of endotracheal tubes and intubation intervention were compared. Group A was ventilated using PU tubes a with conical cuff; they also had continuous cuff pressure measurement and continuous subglottic aspiration. Group B was ventilated using PVC tubes with a cylindrical cuff; the patients underwent intermittent cuff pressure measurement and intermittent subglottic aspiration.

RESULTS

Seven patients in group A (13.2%) and 18 in group B (36.0%) out of 103 were diagnosed with VAP. VAP patients were in general older, stayed longer in the ICU and were ventilated significantly longer compared with the patients with no VAP. Eight more patients in group B died compared with group A. Moreover, subjects in group A survived longer. Patient age, hours on mechanical ventilation, and days on an ICU were all positively associated with the occurrence of VAP.

CONCLUSIONS

Prevention parameters in ventilation (PU cuff, conical cuff, continuous subglottic drainage and continuous cuff pressure measurement) could prevent the incidence of VAP in ICU patients.

Unusually High Incidences of Staphylococcus aureus Infection within Studies of Ventilator Associated Pneumonia Prevention Using Topical Antibiotics: Benchmarking the Evidence Base

Selective digestive decontamination (SDD, topical antibiotic regimens applied to the respiratory tract) appears effective for preventing ventilator associated pneumonia (VAP) in intensive care unit (ICU) patients. However, potential contextual effects of SDD on Staphylococcus aureus infections in the ICU remain unclear. The S. aureus ventilator associated pneumonia (S. aureus VAP), VAP overall and S. aureus bacteremia incidences within component (control and intervention) groups within 27 SDD studies were benchmarked against 115 observational groups. Component groups from 66 studies of various interventions other than SDD provided additional points of reference. In 27 SDD study control groups, the mean S. aureus VAP incidence is 9.6% (95% CI; 6.9–13.2) versus a benchmark derived from 115 observational groups being 4.8% (95% CI; 4.2–5.6). In nine SDD study control groups the mean S. aureus bacteremia incidence is 3.8% (95% CI; 2.1–5.7) versus a benchmark derived from 10 observational groups being 2.1% (95% CI; 1.1–4.1). The incidences of S. aureus VAP and S. aureus bacteremia within the control groups of SDD studies are each higher than literature derived benchmarks. Paradoxically, within the SDD intervention groups, the incidences of both S. aureus VAP and VAP overall are more similar to the benchmarks.

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.

Optimization of Endotracheal Tube Cuff Pressure by Monitoring CO2 Levels in the Subglottic Space in Mechanically Ventilated Patients: A Randomized Controlled Trial

BACKGROUND

Many of the complications of mechanical ventilation are related to inappropriate endotracheal tube (ETT) cuff pressure. The aim of the current study was to evaluate the effectiveness of automatic cuff pressure closed-loop control in patients under prolonged intubation, where presence of carbon dioxide (CO2) in the subglottic space is used as an indicator for leaks. The primary outcome of the study is leakage around the cuff quantified using the area under the curve (AUC) of CO2 leakage over time.

METHODS

This was a multicenter, prospective, randomized controlled, noninferiority trial including intensive care unit patients. All patients were intubated with the AnapnoGuard ETT, which has an extra lumen used to monitor CO2 levels in the subglottic space.The study group was connected to the AnapnoGuard system operating with cuff control adjusted automatically based on subglottic CO2 (automatic group). The control group was connected to the AnapnoGuard system, while cuff pressure was managed manually using a manometer 3 times/d (manual group). The system recorded around cuff CO2 leakage in both groups.

RESULTS

Seventy-two patients were recruited and 64 included in the final analysis. The mean hourly around cuff CO2 leak (mm Hg AUC/h) was 0.22 ± 0.32 in the manual group and 0.09 ± 0.04 in the automatic group (P = .01) where the lower bound of the 1-sided 95% confidence interval was 0.05, demonstrating noninferiority (>-0.033). Additionally, the 2-sided 95% confidence interval was 0.010 to 0.196, showing superiority (>0.0) as well. Significant CO2 leakage (CO2 >2 mm Hg) was 0.027 ± 0.057 (mm Hg AUC/h) in the automatic group versus 0.296 ± 0.784 (mm Hg AUC/h) in the manual group (P = .025). In addition, cuff pressures were in the predefined safety range 97.6% of the time in the automatic group compared to 48.2% in the automatic group (P < .001).

CONCLUSIONS

This study shows that the automatic cuff pressure group is not only noninferior but also superior compared to the manual cuff pressure group. Thus, the use of automatic cuff pressure control based on subglottic measurements of CO2 levels is an effective method for ETT cuff pressure optimization. The method is safe and can be easily utilized with any intubated patient.

Multicentre randomised controlled trial to investigate the usefulness of continuous pneumatic regulation of tracheal cuff pressure for reducing ventilator-associated pneumonia in mechanically ventilated severe trauma patients: the AGATE study protocol

INTRODUCTION

Severe trauma represents the leading cause of mortality worldwide. While 80% of deaths occur within the first 24 hours after trauma, 20% occur later and are mainly due to healthcare-associated infections, including ventilator-associated pneumonia (VAP). Preventing underinflation of the tracheal cuff is recommended to reduce microaspiration, which plays a major role in the pathogenesis of VAP. Automatic devices facilitate the regulation of tracheal cuff pressure, and their implementation has the potential to reduce VAP. The objective of this work is to determine whether continuous regulation of tracheal cuff pressure using a pneumatic device reduces the incidence of VAP compared with intermittent control in severe trauma patients.

METHODS AND ANALYSIS

This multicentre randomised controlled and open-label trial will include patients suffering from severe trauma who are admitted within the first 24 hours, who require invasive mechanical ventilation to longer than 48 hours. Their tracheal cuff pressure will be monitored either once every 8 hours (control group) or continuously using a pneumatic device (intervention group). The primary end point is the proportion of patients that develop VAP in the intensive care unit (ICU) at day 28. The secondary end points include the proportion of patients that develop VAP in the ICU, early (≤7 days) or late (>7 days) VAP, time until the first VAP diagnosis, the number of ventilator-free days and antibiotic-free days, the length of stay in the ICU, the proportion of patients with ventilator-associated events and that die during their ICU stay.

ETHICS AND DISSEMINATION

This protocol has been approved by the ethics committee of Poitiers University Hospital, and will be carried out according to the principles of the Declaration of Helsinki and the Good Clinical Practice guidelines. The results of this study will be disseminated through presentation at scientific conferences and publication in peer-reviewed journals.

TRIAL REGISTRATION

Clinical Trials NCT02534974.

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.

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.

[Ventilator-associated pneumonia (VAP) : A risk already at the time of anesthetic induction]

BACKGROUND

Ventilator-associated pneumonia (VAP) is one of the most common and preventable infections in mechanically ventilated patients. It is associated with a high mortality rate. To prevent VAP, various strategies address this issue using "VAP-bundles", which are implemented in many intensive care units. The risk of acquiring VAP starts with the induction of anesthesia, strictly speaking at the time of intubation. This article considers measures to prevent VAP during general anesthesia in adult patients (>18 years). Procedures beyond standard hygienic precautions for VAP prevention are reviewed.

METHODS

A literature search in different databases (PubMed, Cochrane, Ovid und CINAHL) over the last five years.

RESULTS

Beyond standard hygienic precautions, microaspiration should be avoided to prevent VAP. During mechanical ventilation at least 5 cm H₂O PEEP is advised. Continuous monitoring and adjustment of cuff pressure is necessary. All patients mechanically ventilated after general anesthesia for more than 24 h should be intubated with an ETT with a port for subglottic suctioning.

Microbiome, biofilms, and pneumonia in the ICU

PURPOSE OF REVIEW

Lower respiratory tract infections remain one of the leading causes of death in the world. Recently, the introduction of molecular methods based on DNA sequencing and microarrays for the identification of nonculturable microorganisms and subspecies variations has challenged the previous 'one bug - one disease' paradigm, providing us with a broader view on human microbial communities and their role in the development of infectious diseases. The purpose of this review is to describe recent understanding of the role of microbiome and bacterial biofilm in the development of lung infections, and, at the same time, to present new areas of research opportunities.

RECENT FINDINGS

The review describes recent literature in cystic fibrosis patients, chronic obstructive pulmonary disease patients, and literature in mechanically ventilated patients that helped to elucidate the role of microbiome and biofilm formation in the development of pneumonia.

SUMMARY

The characterization of the human microbiome and biofilms has changed our understanding of lower respiratory tract infections. More comprehensive, sensitive, and fast methods for bacterial, fungal, and viral detection are warranted to establish the colonization of the lower respiratory tract in healthy individuals and sick patients. Future research might explore the global bacterial, fungal, and viral pulmonary ecosystems and their interdependence to target novel preventive approaches and therapeutic strategies in chronic and acute lung infections.

Subglottic secretion suction for preventing ventilator-associated pneumonia: an updated meta-analysis and trial sequential analysis

Background

Potential benefits of subglottic secretion suction for preventing ventilator-associated pneumonia (VAP) are not fully understood.

Methods

We searched Cochrane Central, PubMed, and EMBASE up to March 2016 to identify randomized controlled trials (RCTs) that compared subglottic secretion suction versus non-subglottic secretion suction in adults with mechanical ventilation. Meta-analysis was conducted using Revman 5.3, trial sequential analysis (TSA) 0.9 and STATA 12.0. The primary outcome was incidence of VAP. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was used to evaluate the level of evidence.

Results

Twenty RCTs (N = 3544) were identified. Subglottic secretion suction was associated with reduction of VAP incidence in four high quality trials (relative risk (RR) 0.54, 95 % confidence interval (CI) 0.40–0.74; p < 0.00001) and in all trials (RR = 0.55, 95 % CI 0.48– 0.63; p < 0.00001). Sensitivity analyses did not show differences in the pooled results. Additionally, the results of the above-mentioned analyses were confirmed in TSA. GRADE level was high. Subglottic secretion suction significantly reduced incidence of early onset VAP, gram-positive or gram-negative bacteria causing VAP, and duration of mechanical ventilation. It delayed the time-to-onset of VAP. However, no significant differences in late onset VAP, intensive care unit (ICU) mortality, hospital mortality, or ICU length of stay were found.

Conclusions

Subglottic secretion suction decreased VAP incidence and duration of mechanical ventilation and delayed VAP onset. However, subglottic secretion suction did not reduce mortality and length of ICU stay. Subglottic secretion suction is recommended for preventing VAP and for reducing ventilation length, especially in the population at high risk of early onset VAP.

Trial registration

A protocol of this meta-analysis has been registered on PROSPERO (registration number: CRD42015015715); registered on 5 January 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1527-7) contains supplementary material, which is available to authorized users.

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.

The value of polyurethane-cuffed endotracheal tubes to reduce microaspiration and intubation-related pneumonia: a systematic review of laboratory and clinical studies

Background

When conventional high-volume, low-pressure cuffs of endotracheal tubes (ETTs) are inflated, channel formation due to folds in the cuff wall can occur. These channels facilitate microaspiration of subglottic secretions, which is the main pathogenic mechanism leading to intubation-related pneumonia. Ultrathin polyurethane (PU)-cuffed ETTs are developed to minimize channel formation in the cuff wall and therefore the risk of microaspiration and respiratory infections.

Methods

We systematically reviewed the available literature for laboratory and clinical studies comparing fluid leakage or microaspiration and/or rates of respiratory infections between ETTs with polyvinyl chloride (PVC) cuffs and ETTs with PU cuffs.

Results

The literature search revealed nine in vitro experiments, one in vivo (animal) experiment, and five clinical studies. Among the 9 in vitro studies, 10 types of PU-cuffed ETTs were compared with 17 types of PVC-cuffed tubes, accounting for 67 vs. 108 experiments with 36 PU-cuffed tubes and 42 PVC-cuffed tubes, respectively. Among the clinical studies, three randomized controlled trials (RCTs) were identified that involved 708 patients. In this review, we provide evidence that PU cuffs protect more efficiently than PVC cuffs against fluid leakage or microaspiration. All studies with leakage and/or microaspiration as the primary outcome demonstrated significantly less leakage (eight in vitro and two clinical studies) or at least a tendency toward more efficient sealing (one in vivo animal experiment). In particular, high-risk patients intubated for shorter periods may benefit from the more effective sealing capacity afforded by PU cuffs. For example, cardiac surgery patients experienced a lower risk of early postoperative pneumonia in one RCT. The evidence that PU-cuffed tubes prevent ventilator-associated pneumonia (VAP) is less robust, probably because microaspiration is postponed rather than eliminated. One RCT demonstrated no difference in VAP risk between patients intubated with either PU-cuffed or PVC-cuffed tubes, and one before-after trial demonstrated a favorable reduction in VAP rates following the introduction of PU-cuffed tubes.

Conclusions

Current evidence can support the use of PU-cuffed ETTs in high-risk surgical patients, while there is only very limited evidence that PU cuffs prevent pneumonia in patients ventilated for prolonged periods.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1380-8) contains supplementary material, which is available to authorized users.

Tapered-cuff Endotracheal Tube Does Not Prevent Early Postoperative Pneumonia Compared with Spherical-cuff Endotracheal Tube after Major Vascular Surgery

Background

Patients undergoing major vascular surgery often develop postoperative pneumonia that impacts their outcomes. Conflicting data exist concerning the potential benefit of tapered-shaped cuffs on tracheal sealing. The primary objective of this study was to assess the efficiency of a polyvinyl chloride tapered-cuff endotracheal tube at reducing the postoperative pneumonia rate after major vascular surgery. Secondary objectives were to determine its impact on microaspiration, ventilator-associated pneumonia rate, and inner cuff pressure.

Methods

This prospective randomized controlled study included 109 patients who were randomly assigned to receive either spherical- (standard cuff) or taper-shaped (tapered cuff) endotracheal tubes inserted after anesthesia induction and then admitted to the intensive care unit after major vascular surgery. Cuff pressure was continuously recorded over 5 h. Pepsin and α-amylase concentrations in tracheal aspirates were quantified on postoperative days 1 and 2. The primary outcome was the early postoperative pneumonia frequency.

Results

Comparing the tapered-cuff with standard-cuff group, respectively, postoperative pneumonia rates were comparable (42 vs. 44%, P = 0.87) and the percentage (interquartile range) of cuff-pressure time with overinflation was significantly higher (16.1% [1.5 to 50] vs. 0.6% [0 to 8.3], P = 0.01), with a 2.5-fold higher coefficient of variation (20.2 [10.6 to 29.4] vs. 7.6 [6.2 to 10.2], P &lt; 0.001). Although microaspiration frequencies were high, they did not differ between groups.

Conclusion

For major vascular surgery patients, polyvinyl chloride tapered-cuff endotracheal tubes with intermittent cuff-pressure control did not lower the early postoperative pneumonia frequency and did not prevent microaspiration.

Performance comparison of a new automated cuff pressure controller with currently available devices in both basic research and clinical settings

Background

The management of tracheal tube cuff pressure in patients receiving mechanical ventilation is important for the prevention of ventilator-associated pneumonia. Currently, cuff pressure is intermittently monitored with a pressure gauge and adjusted when necessary in a routine practice. However, this method results in wide variations in pressure, and adequate management is difficult due to the spontaneous release of air from the cuff, which reduces cuff pressure. In order to continuously maintain a uniform cuff pressure, we developed a new automated cuff pressure controller and compared its properties with existing devices.

Methods

The effectiveness of the new device was assessed with a model trachea/lung and tracheal tube by measuring cuff pressure while on mechanical ventilation. An electrically powered automatic cuff controller or manual cuff pressure control was used for comparison purposes. The effectiveness of the new device was also examined in patients receiving mechanical ventilation by continuously measuring cuff pressure for a 24-h period.

Results

Cuff pressure was uniformly maintained with the new device. Moreover, in the clinical setting, variation in pressure from the set pressure was minimal with both the new device and existing device, relative to the intermittent monitoring method. This suggests that, as with the existing device, uniform cuff pressure management is possible with the new device.

Conclusions

Our results demonstrate the ability of the new cuff pressure controller to manage cuff pressure without the need of a power source, highlighting its potential utility in clinical settings.

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.

The Vexing Problem of Ventilator-Associated Pneumonia: Observations on Pathophysiology, Public Policy, and Clinical Science

Ventilator-associated pneumonia (VAP) is an acquired infection related primarily to the consequences of prolonged endotracheal intubation. It is considered the most important infectious challenge in the critical care setting. Preventable complications of hospital care are considered an important source of wasted health-care costs believed to consume up to 47% of annual expenditures in the United States. Whether VAP is preventable has become a highly contentious debate since public reporting commenced a decade ago. This selective review focuses on specific aspects of this debate, including the inherent vagaries in the diagnosis of VAP and the marked disparities between VAP rates based on clinical diagnosis versus surveillance data. Also discussed is how this debate has impacted public policy, leading to the new paradigm of ventilator-associated events. The limited ability of artificial airways to prevent microaspiration and biofilm build-up, as well as non-modifiable conditions increasing the risk of VAP, is described in detail. In addition, the origins of the mistaken but widely embraced notion that zero VAP is a realistic achievement are examined.

Postextubation laryngeal edema and stridor resulting in respiratory failure in critically ill adult patients: updated review

Endotracheal intubation is frequently complicated by laryngeal edema, which may present as postextubation stridor or respiratory difficulty or both. Ultimately, postextubation laryngeal edema may result in respiratory failure with subsequent reintubation. Risk factors for postextubation laryngeal edema include female gender, large tube size, and prolonged intubation. Although patients at low risk for postextubation respiratory insufficiency due to laryngeal edema can be identified by the cuff leak test or laryngeal ultrasound, no reliable test for the identification of high-risk patients is currently available. If applied in a timely manner, intravenous or nebulized corticosteroids can prevent postextubation laryngeal edema; however, the inability to identify high-risk patients prevents the targeted pretreatment of these patients. Therefore, the decision to start corticosteroids should be made on an individual basis and on the basis of the outcome of the cuff leak test and additional risk factors. The preferential treatment of postextubation laryngeal edema consists of intravenous or nebulized corticosteroids combined with nebulized epinephrine, although no data on the optimal treatment algorithm are available. In the presence of respiratory failure, reintubation should be performed without delay. Application of noninvasive ventilation or inhalation of a helium/oxygen mixture is not indicated since it does not improve outcome and increases the delay to intubation.

A 2015 Update on Ventilator-Associated Pneumonia: New Insights on Its Prevention, Diagnosis, and Treatment

Ventilator-associated pneumonia (VAP), an infection of the lower respiratory tract which occurs in association with mechanical ventilation, is one of the most common causes of nosocomial infection in the intensive care unit (ICU). VAP causes significant morbidity and mortality in critically ill patients including increased duration of mechanical ventilation, ICU stay and hospitalization. Current knowledge for its prevention, diagnosis and management is therefore important clinically and is the basis for this review. We discuss recent changes in VAP surveillance nomenclature incorporating ventilator-associated conditions and ventilator-associated events, terms recently proposed by the Centers for Disease Control. To the extent possible, we rely predominantly on data from randomized control trials (RCTs) and meta-analyses.