Intubation-related tracheal ischemic lesions: incidence, risk factors, and outcome

Association between septic shock and tracheal injury score in intensive care unit patients with invasive ventilation: a prospective single-centre cohort study in China

OBJECTIVES

There was no evidence regarding the relationship between septic shock and tracheal injury scores. Investigate whether septic shock was independently associated with tracheal injury scores in intensive care unit (ICU) patients with invasive ventilation.

DESIGN

Prospective observational cohort study.

SETTING

Our study was conducted in a Class III hospital in Hebei province, China.

PARTICIPANTS

Patients over 18 years of age admitted to the ICU between 31 May 2020 and 3 May 2022 with a tracheal tube and expected to be on the tube for more than 24 hours.

PRIMARY AND SECONDARY OUTCOME MEASURES

Tracheal injuries were evaluated by examining hyperaemia, ischaemia, ulcers and tracheal perforation by fiberoptic bronchoscope. Depending on the number of lesions, the lesions were further classified as moderate, severe or confluent.

RESULTS

Among the 97 selected participants, the average age was 56.6±16.5 years, with approximately 64.9% being men. The results of adjusted linear regression showed that septic shock was associated with tracheal injury scores (β: 2.99; 95% CI 0.70 to 5.29). Subgroup analysis revealed a stronger association with a duration of intubation ≥8 days (p=0.013).

CONCLUSION

Patients with septic shock exhibit significantly higher tracheal injury scores compared with those without septic shock, suggesting that septic shock may serve as an independent risk factor for tracheal injury.

TRIAL REGISTRATION NUMBER

ChiCTR2000037842, registered 03 September 2020. Retrospectively registered, https://www.chictr.org.cn/edit.aspx?pid=57011&htm=4.

Tracheal ulcer development from high volume, low-pressure cuffed endotracheal tubes

INTRODUCTION

Iatrogenic injury to the larynx, particularly the vocal cords from prolonged intubation, has been well-studied; however, tracheal injuries are rarely reported. This study investigates the effectiveness of cuffed, high-volume, low-pressure endotracheal tubes in preventing the development of tracheal ulcers in intubated subjects.

METHODS

A retrospective, IRB-approved review was performed on 1355 subjects who underwent percutaneous tracheostomy from 2002 to 2018. The presence and severity of tracheal ulcers were collected using documentation and photos during percutaneous tracheostomy placement. Primary outcome measures included: the length of time on a ventilator until tracheostomy (LOVT), length of hospitalization (LOH), and mortality in relationship to the severity of the tracheal injury. Data was reported as n (%) and median (IQR). The differences in means between groups were analyzed by ANOVA and Chi-square test with an alpha of 0.05.

RESULTS

206 subjects met the inclusion criteria; 65 subjects had an absence of tracheal injury, and 141 subjects developed tracheal ulcers. Subjects with tracheal ulcers were grouped by the following severity scale: no ulcer; mild ulcer (minimal mucosal erosion with exudate); moderate ulcer (mucosal erosion); and severe (tracheal ring exposure). There were no statistically significant differences in age (p = 0.99), gender (p = 0.83), BMI (p = 0.44), LOH (p = 0.88), LOVT (p = 0.93), and mortality (p = 0.306) between subjects with differing severity of ulcers. The average annual incidence of clinically significant ulcers (moderate and severe) was 2.2 %.

CONCLUSIONS

The lack of statistical correlation between the duration of intubation and tracheal ulcer severity, along with a low annual incidence of tracheal ulcers, supports the improved safety of high-volume, low-pressure cylindrical, cuffed endotracheal tubes. This study is among the first to specifically focus on injuries at the level of the cuff and tip of endotracheal tubes with implications in preventive measures and potential product design changes.

Is endotracheal tube displacement during head and neck extension due to ascending movement or tracheal lengthening? An observational ultrasonographic study

Complications of the endotracheal tube (ETT) displacement during head and neck positional changes are related to not only the tip position but also the cuff pressure against the larynx. Here, we evaluated movement of the ETT cuff relative to laryngeal structures as well as tip displacement from the carina.Sixty-two patients scheduled for thyroidectomy were recruited. The distance from the cricoid cartilage to the upper margin of the cuff (CC) and that from the ETT tip to the carina (TC) were measured using ultrasonography and fiberoptic bronchoscopy, respectively, during flexion and extension. The total tracheal length (TTL) was defined as the combination of CC, TC, and the distance from the upper margin of the cuff to the tip.During flexion, the CC and TC were 1.5 ± 0.6 and 2.9 ± 1.0 cm respectively. Seven patients (11.7%) exhibited excessively deep intubation. After adjusting the cuff position under ultrasonography (CC = 0), the tip position was corrected in 96.7%. While the TC increased by 2.1 ± 1.0 cm after the positional change in extension, the CC decreased by 0.6 ± 0.7 cm because the TTL lengthened (1.4 ± 1.1 cm). Four patients (6.7%) exhibited excessive cuff displacement beyond the cricoid cartilage, which could have been corrected under ultrasonography.In conclusion, the ETT cuff displaced toward the larynx in a less degree than the tip did from the carina due to the tracheal lengthening during head and neck extension. Nevertheless, we suggest that ultrasonographic assessment of cuff position may avoid ETT misplacement. Trial registration https://cris.nih.go.kr/ (approval no. KCT0005319); registered on May 14, 2019.

Multidisciplinary management of laryngeal pathology identified in patients with COVID-19 following trans-laryngeal intubation and tracheostomy

Background

COVID-19 disease often requires invasive ventilatory support. Trans-laryngeal intubation of the trachea may cause laryngeal injury, possibly compounded by coronavirus infection. Fibreoptic Endoscopic Evaluation of Swallowing (FEES) provides anatomical and functional assessment of the larynx, guiding multidisciplinary management. Our aims were to observe the nature of laryngeal abnormalities in patients with COVID-19 following prolonged trans-laryngeal intubation and tracheostomy, and to describe their impact on functional laryngeal outcomes, such as tracheostomy weaning.

Methods

A retrospective observational cohort analysis was undertaken between March and December 2020, at a UK tertiary hospital. The Speech and Language Therapy team assessed patients recovering from COVID-19 with voice/swallowing problems identified following trans-laryngeal intubation or tracheostomy using FEES. Laryngeal pathology, treatments, and outcomes relating to tracheostomy and oral feeding were noted.

Results

Twenty-five FEES performed on 16 patients identified a median of 3 (IQR 2-4) laryngeal abnormalities, with 63% considered clinically significant. Most common pathologies were: oedema (n = 12, 75%); abnormal movement (n = 12, 75%); atypical lesions (n = 11, 69%); and erythema (n = 6, 38%). FEES influenced management: identifying silent aspiration (88% of patients who aspirated (n = 8)), airway patency issues impacting tracheostomy weaning (n = 8, 50%), targeted dysphagia therapy (n = 7, 44%); ENT referral (n = 6, 38%) and reflux management (n = 5, 31%).

Conclusions

FEES is beneficial in identifying occult pathologies and guiding management for laryngeal recovery. In our cohort, the incidence of laryngeal pathology was higher than a non-COVID-19 cohort with similar characteristics. We recommend multidisciplinary investigation and management of patients recovering from COVID-19 who required prolonged trans-laryngeal intubation and/or tracheostomy to optimise laryngeal recovery.

Complications of invasive mechanical ventilation in critically Ill Covid-19 patients - A narrative review

Critically ill COVID-19 patients have to undergo positive pressure ventilation, a non-physiological and invasive intervention that can be lifesaving in severe ARDS. Similar to any other intervention, it has its pros and cons. Despite following Lung Protective Ventilation (LPV), some of the complications are frequently reported in these critically ill patients and significantly impact overall mortality. The complications related to invasive mechanical ventilation (IMV) in critically ill COVID-19 patients can be broadly divided into pulmonary and non-pulmonary. Among pulmonary complications, the most frequent is ventilator-associated pneumonia. Others are barotrauma, including subcutaneous emphysema, pneumomediastinum, pneumothorax, bullous lesions, cardiopulmonary effects of right ventricular dysfunction, and pulmonary complications mimicking cardiac failure, including pulmonary edema. Tracheal complications, including full-thickness tracheal lesions (FTTLs) and tracheoesophageal fistulas (TEFs) are serious but rare complications. Non-Pulmonary complications include neurological, nephrological, ocular, and oral complications.

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The complications related to IMV in critically ill covid 19 patients can be broadly divided into pulmonary and non-pulmonary complications.

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Among pulmonary complications the most frequent is Ventilator associated pneumonia.

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Others are Barotrauma, Cardiopulmonary effects of right ventricular dysfunction & Pulmonary complications mimicking cardiac failure including pulmonary edema, tracheal complications including full thickness tracheal lesions & tracheoesophageal fistulas.

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Non-Pulmonary complications of prolonged IMV include neurological, nephrological, ocular and oral complications.

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.

Extensive Tracheal Injuries: A Reasoned Multistep Approach to Guarantee Mechanical Ventilatory Support Developed During the COVID-19 Pandemic

The COVID-19 pandemic has notably increased the need for prolonged mechanical ventilation (MV) in patients with respiratory failure. This has increased the risk of extensive tracheal injury (ETI) associated with life-threatening complications in complex cases. Furthermore, tracheal injury treatment in patients with COVID-19 has not been described yet. Three patients with COVID-19 and ETI who required MV between April and November 2020 were included. A multistep approach was performed to restore tracheal integrity with a custom-remodeled stent and tracheostomy tube placement to allow ventilatory support. Efficient MV with no residual air leaks was obtained in all cases. One patient died 6 weeks after the procedure due to COVID-19 lung damage. Two patients have completely been weaned from MV. This multistep procedure could be used to maintain ventilatory support in the case of ETI, working as a bridge to subsequent surgery when clinical conditions improve.

Molecular Mechanisms and Physiological Changes behind Benign Tracheal and Subglottic Stenosis in Adults

Laryngotracheal stenosis (LTS) is a complex and heterogeneous disease whose pathogenesis remains unclear. LTS is considered to be the result of aberrant wound-healing process that leads to fibrotic scarring, originating from different aetiology. Although iatrogenic aetiology is the main cause of subglottic or tracheal stenosis, also autoimmune and infectious diseases may be involved in causing LTS. Furthermore, fibrotic obstruction in the anatomic region under the glottis can also be diagnosed without apparent aetiology after a comprehensive workup; in this case, the pathological process is called idiopathic subglottic stenosis (iSGS). So far, the laryngotracheal scar resulting from airway injury due to different diseases was considered as inert tissue requiring surgical removal to restore airway patency. However, this assumption has recently been revised by regarding the tracheal scarring process as a fibroinflammatory event due to immunological alteration, similar to other fibrotic diseases. Recent acquisitions suggest that different factors, such as growth factors, cytokines, altered fibroblast function and genetic susceptibility, can all interact in a complex way leading to aberrant and fibrotic wound healing after an insult that acts as a trigger. However, also physiological derangement due to LTS could play a role in promoting dysregulated response to laryngo-tracheal mucosal injury, through biomechanical stress and mechanotransduction activation. The aim of this narrative review is to present the state-of-the-art knowledge regarding molecular mechanisms, as well as mechanical and physio-pathological features behind LTS.

Experimental Assessment of Cuff Pressures on the Walls of a Trachea-Like Model Using Force Sensing Resistors: Insights for Patient Management in Intensive Care Unit Settings

The COVID-19 outbreak has increased the incidence of tracheal lesions in patients who underwent invasive mechanical ventilation. We measured the pressure exerted by the cuff on the walls of a test bench mimicking the laryngotracheal tract. The test bench was designed to acquire the pressure exerted by endotracheal tube cuffs inflated inside an artificial model of a human trachea. The experimental protocol consisted of measuring pressure values before and after applying a maneuver on two types of endotracheal tubes placed in two mock-ups resembling two different sized tracheal tracts. Increasing pressure values were used to inflate the cuff and the pressures were recorded in two different body positions. The recorded pressure increased proportionally to the input pressure. Moreover, the pressure values measured when using the non-armored (NA) tube were usually higher than those recorded when using the armored (A) tube. A periodic check of the cuff pressure upon changing the body position and/or when performing maneuvers on the tube appears to be necessary to prevent a pressure increase on the tracheal wall. In addition, in our model, the cuff of the A tube gave a more stable output pressure on the tracheal wall than that of the NA tube.

Prehospital Intubations Are Associated with Elevated Endotracheal Tube Cuff Pressures: A Cross-Sectional Study Characterizing ETT Cuff Pressures at a Tertiary Care Emergency Department

INTRODUCTION

Emergency Medical Services (EMS) providers are trained to place endotracheal tubes (ETTs) in the prehospital setting when indicated. Endotracheal tube cuffs are traditionally inflated with 10cc of air to provide adequate seal against the tracheal lumen. There is literature suggesting that many ETTs are inflated well beyond the accepted safe pressures of 20-30cmH2O, leading to potential complications including ischemia, necrosis, scarring, and stenosis of the tracheal wall. Currently, EMS providers do not routinely check ETT cuff pressures. It was hypothesized that the average ETT cuff pressure of patients arriving at the study site who were intubated by EMS exceeds the safe pressure range of 20-30cmH2O.

OBJECTIVES

While ETT cuff inflation is necessary to close the respiratory system, thus preventing air leaks and aspiration, there is evidence to suggest that over-inflated ETT cuffs can cause long-term complications. The purpose of this study is to characterize the cuff pressures of ETTs placed by EMS providers.

METHODS

This project was a single center, prospective observational study. Endotracheal tube cuff pressures were measured and recorded for adult patients intubated by EMS providers prior to arrival at a large, urban, tertiary care center over a nine-month period. All data were collected by respiratory therapists utilizing a cuff pressure measurement device which had a detectable range of 0-100cmH2O and was designed as a syringe. Results including basic patient demographics, cuff pressure, tube size, and EMS service were recorded.

RESULTS

In total, 45 measurements from six EMS services were included with ETT sizes ranging from 6.5-8.0mm. Mean patient age was 52.2 years (67.7% male). Mean cuff pressure was 81.8cmH2O with a range of 15 to 100 and a median of 100. The mode was 100cmH2O; 40 out of 45 (88.9%) cuff pressures were above 30cmH2O. Linear regression showed no correlation between age and ETT cuff pressure or between ETT size and cuff pressure. Two-tailed T tests did not show a significant difference in the mean cuff pressure between female versus male patients.

CONCLUSION

An overwhelming majority of prehospital intubations are associated with elevated cuff pressures, and cuff pressure monitoring education is indicated to address this phenomenon.

Post-intubation subglottic stenosis: aetiology at the cellular and molecular level

Subglottic stenosis (SGS) is a narrowing of the airway just below the vocal cords. This narrowing typically consists of fibrotic scar tissue, which may be due to a variety of diseases. This review focuses on post-intubation (PI) SGS. SGS can result in partial or complete narrowing of the airway. This narrowing is caused by fibrosis and can cause serious breathing difficulties. It can occur in both adults and children. The pathogenesis of post-intubation SGS is not well understood; however, it is considered to be the product of an abnormal healing process. This review discusses how intubation can change the local micro-environment, leading to dysregulated tissue repair. We discuss how mucosal inflammation, local hypoxia and biomechanical stress associated with intubation can promote excess tissue deposition that occurs during the pathological process of SGS.

COVID-19 may cause an increased incidence of subglottic stenosis (SGS). In this review, the cellular and molecular aetiology of post-intubation SGS is outlined and we discuss how better knowledge of the underlying biology can inform SGS management.https://bit.ly/2RSliRK

Evaluation of the Incidence and Potential Mechanisms of Tracheal Complications in Patients With COVID-19

Importance

Full-thickness tracheal lesions and tracheoesophageal fistulas are severe complications of invasive mechanical ventilation. The incidence of tracheal complications in ventilated patients with coronavirus disease 2019 (COVID-19) is unknown.

Objective

To evaluate whether patients with COVID-19 have a higher incidence of full-thickness tracheal lesions and tracheoesophageal fistulas than matched controls and to investigate potential mechanisms.

Design, Setting, and Participants

This is a retrospective cohort study in patients admitted to the intensive care unit in a tertiary referral hospital. Among 98 consecutive patients with COVID-19 with severe respiratory failure, 30 underwent prolonged (≥14 days) invasive mechanical ventilation and were included in the COVID-19 group. The control group included 45 patients without COVID-19. Patients with COVID-19 were selected from March 1 to May 31, 2020, while the control group was selected from March 1 to May 31, 2019.

Exposures

Patients with COVID-19 had severe acute respiratory syndrome coronavirus 2 infection diagnosed by nasopharyngeal/oropharyngeal swabs and were treated according to local therapeutic procedures.

Main Outcomes and Measures

The primary study outcome was the incidence of full-thickness tracheal lesions or tracheoesophageal fistulas in patients with prolonged invasive mechanical ventilation.

Results

The mean (SD) age was 68.8 (9.0) years in the COVID-19 group and 68.5 (14.1) years in the control group (effect size, 0.3; 95% CI, -5.0 to 5.6). Eight (27%) and 15 (33%) women were enrolled in the COVID-19 group and the control group, respectively. Fourteen patients (47%) in the COVID-19 group had full-thickness tracheal lesions (n = 10, 33%) or tracheoesophageal fistulas (n = 4, 13%), while 1 patient (2.2%) in the control group had a full-thickness tracheal lesion (odds ratio, 38.4; 95% CI, 4.7 to 316.9). Clinical and radiological presentations of tracheal lesions were pneumomediastinum (n = 10, 71%), pneumothorax (n = 6, 43%), and/or subcutaneous emphysema (n = 13, 93%).

Conclusions and Relevance

In this cohort study, almost half of patients with COVID-19 developed full-thickness tracheal lesions and/or tracheoesophageal fistulas after prolonged invasive mechanical ventilation. Attempts to prevent these lesions should be made and quickly recognized when they occur to avoid potentially life-threatening complications in ventilated patients with COVID-19.

Effect of intraoperative neuromuscular blockade on postoperative sore throat and hoarseness in patients undergoing spinal surgery: a prospective observational study

Intraoperative neuromuscular blockade affects the resting tension between the vocal cords. We assessed the effect of neuromuscular blockade on postoperative sore throat and hoarseness following tracheal intubation in patients undergoing lumbar spinal surgery in the prone position. Altogether, 99 patients were included; 50 patients did not receive neuromuscular blockade, and 49 patients received moderate neuromuscular blockade during the maintenance of anesthesia. Neuromuscular blockade was performed depending on the use of intraoperative neurophysiological monitoring. The number of intubation attempts, time to achieve tracheal intubation, and duration of intubation were recorded accordingly. The incidence and severity of postoperative sore throat and hoarseness was assessed at 1, 6, and 24 h after surgery. The overall cumulative incidence of postoperative sore throat (60% vs. 59%, respectively; P = 1.000) and postoperative hoarseness (68% vs. 61%, respectively; P = 0.532) did not differ between the no neuromuscular blockade and moderate neuromuscular blockade. The incidence and severity of postoperative sore throat and hoarseness was also not different between the moderate and no neuromuscular blockade at each time point after surgery. Nevertheless, the incidences of postoperative sore throat and hoarseness were quite high. Further studies investigating strategies to alleviate them are warranted accordingly.

Cambios fisiológicos relacionados con entrenamiento muscular respiratorio en pacientes con ventilación mecánica

Introducción. El entrenamiento muscular respiratorio es una técnica fisioterapéutica usada para incrementar la fuerza de la musculatura respiratoria, sin embargo pocos estudios han abordado los cambios fisiológicos relacionados con esta intervención en pacientes con ventilación mecánica.Objetivo. Determinar los cambios fisiológicos relacionados con el entrenamiento muscular respiratorio en pacientes con ventilación mecánica.Materiales y métodos. Se realizó un análisis de datos secundarios en el marco del estudio “Eficacia del entrenamiento muscular respiratorio en el destete de la ventilación mecánica en pacientes con ventilación mecánica por 48 horas o más: Un ensayo clínico controlado”. La población estuvo conformada por los 62 pacientes del grupo experimental del estudio principal, quienes recibieron entrenamiento muscular respiratorio. Los valores de frecuencia cardiaca, frecuencia respiratoria, presión arterial, saturación de oxígeno y volumen corriente fueron registrados. La diferencia entre el promedio de cada una de las variables fue analizada mediante la prueba de t pareada, mientras que para el análisis de los cambios fisiológicos entre sesiones de entrenamiento se empleó la prueba de Kruskal-Wallis.Resultados. Se observaron diferencias significativas entre las variables fisiológicas antes y después del entrenamiento muscular respiratorio (p<0.05), a excepción del volumen corriente y la presión arterial media (p>0.05). Por el contrario, no se observaron diferencias significativas en ninguna de las variables fisiológicas entre sesiones de entrenamiento (p>0.05)Conclusiones. El entrenamiento muscular respiratorio es una intervención terapéutica viable y tolerable en esta población.

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.

Intraoperative Endotracheal Cuff Pressure Study: How Education and Availability of Manometers Help Guide Safer Pressures

INTRODUCTION

Endotracheal intubation is a medical procedure that is often indicated in both the perioperative and critical care environments. Cuffed endotracheal tubes (ETT) allow for safer and more efficient delivery of positive pressure ventilation, as well as create a barrier to reduce the risk of micro-aspiration and anesthetic pollution in the operating room environment. Over-inflation of the endotracheal cuff can lead to serious and harmful sequelae. This study aimed to assess if departmental education paired with ready access to a manometer to assess cuff pressure would result in an improvement in the proportion of ETT cuff pressures in the goal range.

MATERIALS AND METHODS

A quality improvement study was conducted at the San Antonio Military Medical Center (SAMMC; Department of Defense hospital in San Antonio, TX). The initiative was divided into three key periods: pre-implementation, implementation, and post-implementation. During the pre-implementation period, ETT cuff pressures were obtained to assess the baseline state of ETT cuff pressures for patients in the operating room; the proportion of in-range (20-30 cmH2O) pressures was calculated. During the implementation phase, operating rooms were equipped with manometers and anesthesia departmental education was performed regarding the use of the manometers. Three months later, post-implementation cuff pressures were measured in the OR, and the proportion of in-range pressures was again calculated.

RESULTS

The pre-implementation data showed an average cuff pressure of 48.92 cmH2O and a median of 38.5 cmH2O. Of the 100 pre-implementation pressures, 20 were in the goal range. Post-implementation data had an average cuff pressure of 41.96 cmH2O and a median of 30 cmH2O. A chi-squared test of pressures in the safe range from the pre-implementation versus post-implementation values yielded a highly significant p-value of 0.0003.

CONCLUSION

The data from this study clearly demonstrated a statistically significant improvement in the proportion of in-range cuff pressures following the quality improvement initiative. This study supports the use of department-wide education and the availability of manometers in each OR to yield safer cuff pressures for intubated patients. This study did not aim to determine an optimal ETT cuff pressure, but utilized data already available to determine a safe cuff pressure. Further research needs to be performed to assess whether routine monitoring of cuff pressure results in improved patient outcomes.

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.

Unintentional endotracheal tube cuff deflation during routine checks: a simulation study

BACKGROUND

Endotracheal tube cuff pressures should be maintained between 20 and 30 cm H₂ O to prevent the aspiration of subglottic secretions past the cuff. Guidance recommends regular monitoring of the cuff pressure, performed using a handheld manometer/inflator. Poor technique can lead to transient deflation of the cuff, leading to the bolus aspiration of upper respiratory tract secretions, tracheal colonization and, ultimately, ventilator-associated pneumonia.

AIMS AND OBJECTIVES

To determine whether intensive care staff transiently deflate the endotracheal tube cuff to below 20 cm H₂ O during routine cuff pressure checks when using a handheld manometer/inflator device.

DESIGN

This was an exploratory simulation study.

METHODS

A sample of medical (n = 10) and nursing staff (n = 10), capable of caring for a tracheally intubated patient, participated in the study on a single day. A mannequin was intubated with a standard oral endotracheal tube with the cuff pressure set at 50 cm H₂ O. Participants were required to check and correct the cuff pressure to the appropriate level with a manometer. The lowest attained and the final target pressures were recorded.

RESULTS

Three doctors were unfamiliar with the manometer and did not attempt measurement. During cuff pressure readjustment, 59% (10/17) of participants transiently deflated the cuff below 20 cm H₂ O and then re-inflated to attain the final pressure. Of these participants, four deflated the cuff pressure to 0 cm H₂ O before re-adjusting it back into range. Most participants, 88% (15/17), corrected the final cuff pressure to between 20 and 30 cm H₂ O.

CONCLUSIONS

Poor technique when using the manometer led to unintentional cuff deflation during routine checks. In clinical practice, this could increase the risk of pulmonary aspiration and ventilator-associated pneumonia. Further research into alternatives for handheld manometers, such as automated continuous cuff pressure monitors, is warranted.

RELEVANCE TO CLINICAL PRACTICE

Cuff deflations can easily occur during routine cuff pressure checks. Staff should be aware of the implications of cuff deflations and seek to improve training with manometers.

Efficacy of respiratory muscle training in weaning of mechanical ventilation in patients with mechanical ventilation for 48hours or more: A Randomized Controlled Clinical Trial

OBJECTIVE

To evaluate the efficacy of respiratory muscular training in the weaning of mechanical ventilation and respiratory muscle strength in patients on mechanical ventilation of 48hours or more.

DESIGN

Randomized controlled trial of parallel groups, double-blind. Ambit: Intensive Care Unit of a IV level clinic in the city of Cali.

PATIENTS

126 patients in mechanical ventilation for 48hours or more.

INTERVENTIONS

The experimental group received daily a respiratory muscle training program with treshold, adjusted to 50% of maximal inspiratory pressure, additional to standard care, conventional received standard care of respiratory physiotherapy. MAIN INTEREST VARIABLES: weaning of mechanical ventilation. Other variables evaluated: respiratory muscle strength, requirement of non-invasive mechanical ventilation and frequency of reintubation.

ANALYSIS

intention-to-treat analysis was performed with all variables evaluated and analysis stratified by sepsis condition.

RESULTS

There were no statistically significant differences in the median weaning time of the MV between the groups or in the probability of extubation between groups (HR: 0.82 95% CI: 0.55-1.20 P=.29). The maximum inspiratory pressure was increased in the experimental group on average 9.43 (17.48) cmsH20 and in the conventional 5.92 (11.90) cmsH20 (P=.48). The difference between the means of change in maximal inspiratory pressure was 0.46 (P=.83 95%CI -3.85 to -4.78).

CONCLUSIONS

respiratory muscle training did not demonstrate efficacy in the reduction of the weaning period of mechanical ventilation nor in the increase of respiratory muscle strength in the study population. Registered study at ClinicalTrials.gov (NCT02469064).

Incidence of airway complications in patients using endotracheal tubes with continuous aspiration of subglottic secretions

BACKGROUND

Continuous aspiration of subglottic secretions is effective in preventing ventilator-associated pneumonia, but it involves a risk of mucosal damage. The main objective of our study was to determine the incidence of airway complications related to continuous aspiration of subglottic secretions.

METHODS

In consecutive adult patients with continuous aspiration of subglottic secretions, we prospectively recorded clinical airway complications during the period after extubation. A multidetector computed tomography of the neck was performed during the period of 5 days following extubation to classify subglottic and tracheal lesions as mucosal thickening, cartilage thickening or deep ulceration.

RESULTS

In the 86 patients included in the study, 6 (6.9%) had transient dyspnea, 7 (8.1%) had upper airway obstruction and 18 (20.9%) had dysphonia at extubation. Univariate analysis identified more attempts required for intubation (2.3 ± 1.1 vs. 1.2 ± 0.5; p = 0.001), difficult intubation (71.4 vs. 10.1%, p = 0.001) and Cormack score III-IV (71.4 vs. 8.8%; p < 0.001) as risk factors for having an upper airway obstruction at extubation. The incidence of failed extubation among patients after planned extubation was 18.9% and 11 patients (12.7%) required tracheostomy. A multidetector computed tomography was performed in 37 patients following extubation, and injuries were observed in 9 patients (24.3%) and classified as tracheal injuries in 2 patients (1 cartilage thickening and 1 mild stenosis with cartilage thickening) and as subglottic mucosal thickenings in 7 patients.

CONCLUSIONS

The incidence of upper airway obstruction after extubation in patients with continuous aspiration of subglottic secretions was 8.1%, and the injuries observed by computed tomography were not severe and located mostly in subglottic space.

Positive end-expiratory pressure adjusted for intra-abdominal pressure - A pilot study

PURPOSE

Intra-abdominal hypertension (IAH) is associated with impaired respiratory function. Animal data suggest that positive end-expiratory pressure (PEEP) levels adjusted to intra-abdominal pressure (IAP) levels may counteract IAH-induced respiratory dysfunction. In this pilot study, our aim was to assess whether PEEP adjusted for IAP can be applied safely in patients with IAH.

MATERIALS AND METHODS

We included patients on mechanical ventilation and with IAH. Patients were excluded with severe cardiovascular dysfunction or severe hypoxemia or if the patient was in imminent danger of dying. Following a recruitment manoeuvre, the following PEEP levels were randomly applied: PEEP of 5cmH₂O (baseline), PEEP=50% of IAP, and PEEP=100% of IAP. After a 30min equilibration period we measured arterial blood gases and cardio-respiratory parameters.

RESULTS

Fifteen patients were enrolled. Six (41%) patients did not tolerate PEEP=100% IAP due to hypoxemia, hypotension or endotracheal cuff leak. PaO₂/FiO₂ ratios were 234 (68), 271 (99), and 329 (107) respectively. The differences were significant (p=0.009) only between baseline and PEEP=100% IAP.

CONCLUSIONS

PEEP=100% of IAP was not well-tolerated and only marginally improved oxygenation in ventilated patients with IAH.

Altitude-Related Change in Endotracheal Tube Cuff Pressures in Helicopter EMS

Introduction

Over-inflation of endotracheal tube (ETT) cuffs has the potential to lead to scarring and stenosis of the trachea.1, 2,3, 4 The air inside an ETT cuff is subject to expansion as atmospheric pressure decreases, as happens with an increase in altitude. Emergency medical services helicopters are not pressurized, thereby providing a good environment for studying the effects of altitude changes ETT cuff pressures. This study aims to explore the relationship between altitude and ETT cuff pressures in a helicopter air-medical transport program.

Methods

ETT cuffs were initially inflated in a nonstandardized manner and then adjusted to a pressure of 25 cmH₂O. The pressure was again measured when the helicopter reached maximum altitude. A final pressure was recorded when the helicopter landed at the receiving facility.

Results

We enrolled 60 subjects in the study. The mean for initial tube cuff pressures was 70 cmH₂O. Maximum altitude for the program ranged from 1,000–3,000 feet above sea level, with a change in altitude from 800–2,480 feet. Mean cuff pressure at altitude was 36.52 ± 8.56 cmH₂O. Despite the significant change in cuff pressure at maximum altitude, there was no relationship found between the maximum altitude and the cuff pressures measured.

Conclusion

Our study failed to demonstrate the expected linear relationship between ETT cuff pressures and the maximum altitude achieved during typical air-medical transportation in our system. At altitudes less than 3,000 feet above sea level, the effect of altitude change on ETT pressure is minimal and does not require a change in practice to saline-filled cuffs.

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.

Cuff Leak Test for the Diagnosis of Post-Extubation Stridor: A Multicenter Evaluation Study

BACKGROUND:

Cuff leak test was developed to predict the occurrence of post-extubation stridor (PES). This study evaluated the diagnostic performance of this test in unselected critically ill patients.

METHODS:

Multicenter prospective study including unselected ventilated patients at the time of their first planned extubation. The diagnostic performance of 4 different cuff leak tests was assessed.

RESULTS:

Post-extubation stridor occurred in 34 (9.4%) of 362 included patients. Compared to patients without PES, patients with PES required more frequently reintubation (6 [17.6%] vs 26 [7.9%], P = .041), prolonged duration of ventilation (6 [3-13] vs 5 [2-9] days, P = .029), and longer intensive care unit (ICU) stay (12 [6-17.5] vs 7.5 [4-13] days, P = .018). However, ICU mortality was similar in both groups (1 [2.9%] vs 23 [7.0%], P = .61). The 4 cuff leak tests display poor diagnostic accuracy: sensitivities ranging from 27% to 46%, specificities from 70% to 88%, positive predictive values from 14% to 19%, and negative predictive values from 92% to 93%.

CONCLUSION:

Post-extubation stridor occurs in less than 10% of unselected critically ill patients. The several cuff leak tests display limited diagnostic performance for the detection of PES. Given the high rate of false positives, routine cuff leak test may expose to undue prolonged mechanical ventilation.

Practical anesthetic considerations in patients undergoing tracheobronchial surgeries: a clinical review of current literature

Tracheobronchial surgeries require close cooperation and extensive communication between the anesthesia providers and the surgeons. Anesthetic management of tracheal and bronchial pathologies differ basically from regular upper airways management, due access to the patients airway is limited, mostly even practically impossible for the anesthesia providers. As a consequence, the surgeon overtakes responsibility for the airway access from the anesthesia provider in the variety of the cases. Preoperative recognition of a difficult airway, detailed planning and being aware of plan B and plan C are the elementary keys to success. Providers have to be aware, that preoperative airway assessment does not always correlate with the ease of oxygenation and ventilation. Therefore, various methods have been described in the literature and several authors have adopted unique ways to manage the airways in a successful manner. With the advancement of surgical techniques over the years, anesthetic management has also evolved tremendously to match the needs. The commonly encountered conditions requiring surgical interventions include post-intubation stenosis and foreign body aspiration. In this review we will discuss the most common pathologies of tracheobronchial lesions and specific anesthetic management considerations related to them.

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.

Endotracheal Tube Cuff Pressures in Patients Intubated Prior to Helicopter EMS Transport

Introduction

Endotracheal intubation is a common intervention in critical care patients undergoing helicopter emergency medical services (HEMS) transportation. Measurement of endotracheal tube (ETT) cuff pressures is not common practice in patients referred to our service. Animal studies have demonstrated an association between the pressure of the ETT cuff on the tracheal mucosa and decreased blood flow leading to mucosal ischemia and scarring. Cuff pressures greater than 30 cmH₂O impede mucosal capillary blood flow. Multiple prior studies have recommended 30 cmH₂O as the maximum safe cuff inflation pressure. This study sought to evaluate the inflation pressures in ETT cuffs of patients presenting to HEMS.

Methods

We enrolled a convenience sample of patients presenting to UMass Memorial LifeFlight who were intubated by the sending facility or emergency medical services (EMS) agency. Flight crews measured the ETT cuff pressures using a commercially available device. Those patients intubated by the flight crew were excluded from this analysis as the cuff was inflated with the manometer to a standardized pressure. Crews logged the results on a research form, and we analyzed the data using Microsoft Excel and an online statistical analysis tool.

Results

We analyzed data for 55 patients. There was a mean age of 57 years (range 18–90). The mean ETT cuff pressure was 70 (95% CI= [61–80]) cmH₂O. The mean lies 40 cmH₂O above the maximum accepted value of 30 cmH₂O (p<0.0001). Eighty-four percent (84%) of patients encountered had pressures above the recommended maximum. The most frequently recorded pressure was >120 cmH₂O, the maximum pressure on the analog gauge.

Conclusion

Patients presenting to HEMS after intubation by the referral agency (EMS or hospital) have ETT cuffs inflated to pressures that are, on average, more than double the recommended maximum. These patients are at risk for tracheal mucosal injury and scarring from decreased mucosal capillary blood flow. Hospital and EMS providers should use ETT cuff manometry to ensure that they inflate ETT cuffs to safe pressures.

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.

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.

Endotracheal tubes for critically ill patients: an in vivo analysis of associated tracheal injury, mucociliary clearance, and sealing efficacy

BACKGROUND

Improvements in the design of the endotracheal tube (ETT) have been achieved in recent years. We evaluated tracheal injury associated with ETTs with novel high-volume low-pressure (HVLP) cuffs and subglottic secretions aspiration (SSA) and the effects on mucociliary clearance (MCC).

METHODS

Twenty-nine pigs were intubated with ETTs comprising cylindrical or tapered cuffs and made of polyvinylchloride (PVC) or polyurethane. In specific ETTs, SSA was performed every 2 h. Following 76 h of mechanical ventilation, pigs were weaned and extubated. Images of the tracheal wall were recorded before intubation, at extubation, and 24 and 96 h thereafter through a fluorescence bronchoscope. We calculated the red-to-green intensity ratio (R/G), an index of tracheal injury, and the green-plus-blue (G+B) intensity, an index of normalcy, of the most injured tracheal regions. MCC was assessed through fluoroscopic tracking of radiopaque markers. After 96 h from extubation, pigs were killed, and a pathologist scored injury.

RESULTS

Cylindrical cuffs presented a smaller increase in R/G vs tapered cuffs (P = .011). Additionally, cuffs made of polyurethane produced a minor increase in R/G (P = .012) and less G+B intensity decline (P = .022) vs PVC cuffs. Particularly, a cuff made of polyurethane and with a smaller outer diameter outperformed all cuffs. SSA-related histologic injury ranged from cilia loss to subepithelial inflammation. MCC was 0.9 ± 1.8 and 0.4 ± 0.9 mm/min for polyurethane and PVC cuffs, respectively (P < .001).

CONCLUSIONS

HVLP cuffs and SSA produce tracheal injury, and the recovery is incomplete up to 96 h following extubation. Small, cylindrical-shaped cuffs made of polyurethane cause less injury. MCC decline is reduced with polyurethane cuffs.

Efficiency of a mechanical device in controlling tracheal cuff pressure in intubated critically ill patients: a randomized controlled study

Background

Cuff pressure (P_cuff) control is mandatory to avoid leakage of oral secretions passing the tracheal tube and tracheal ischemia. The aim of the present trial was to determine the efficacy of a mechanical device (PressureEasy®) in the continuous control of P_cuff in patients intubated with polyvinyl chloride (PVC)-cuffed tracheal tubes, compared with routine care using a manometer.

Methods

This is a prospective, randomized, controlled, cross-over study. All patients requiring intubation with a predicted duration of mechanical ventilation ≥48 h were eligible. Eighteen patients randomly received continuous control of P_cuff with PressureEasy® device for 24 h, followed by discontinuous control (every 4 h) with a manual manometer for 24 h, or vice versa. P_cuff and airway pressure were continuously recorded. P_cuff target was 25 cmH₂O during the two periods.

Results

The percentage of time spent with P_cuff 20–30 cmH₂O (median (IQR) 34 % (17–57) versus 50 % (35–64), p = 0.184) and the percentage of time spent with P_cuff <20 cmH₂O (23 % (5–63) versus 43 % (16–60), p = 0.5) were similar during continuous control of P_cuff and routine care, respectively. However, the percentage of time spent with P_cuff >30 cmH₂O was significantly higher during continuous control compared with routine care of tracheal cuff (26 % (14–39) versus 7 % (1–18), p = 0.002). No significant difference was found in P_cuff (25 (18–28) versus 21 (18–26), p = 0.17), mean airway pressure (14 (10–17) versus 14 (11–16), p = 0.679), or coefficient of variation of P_cuff (19 % (11–26) versus 20 % (11–25), p = 0.679) during continuous control compared with routine care of tracheal cuff, respectively.

Conclusions

PressureEasy® did not demonstrate a better control of P_cuff between 20 and 30 cmH₂O, compared with routine care using a manometer. Moreover, the device use resulted in significantly higher time spent with overinflation of tracheal cuff, which might increase the risk for tracheal ischemic lesions.

Trial registration

Clinicaltrial.gov: NCT02109003

Continuous control of tracheal cuff pressure: an effective measure to prevent ventilator-associated pneumonia?

In a previous issue of Critical Care, Lorente and colleagues reported the results of a prospective observational study aiming at evaluating the effect of continuous control of cuff pressure (P_cuff ) on the incidence of ventilator-associated pneumonia (VAP). The results suggest a beneficial impact of this intervention on VAP prevention, which is in line with the results of a recent randomized controlled study. However, another randomized controlled study found no significant impact of continuous control of P_cuff on VAP incidence. Several differences regarding the device used to control P_cuff, study population, and design might explain the different reported results. Future randomized multicenter studies are needed to confirm the beneficial effect of continuous control of P_cuff on VAP incidence. Furthermore, the efficiency and cost-effectiveness of different available devices should be compared. Meanwhile, given the single-center design and the limitations of the available studies, no strong recommendation can be made regarding continuous control of P_cuff as a preventive measure of VAP.

Continuous control of tracheal cuff pressure for the prevention of ventilator-associated pneumonia in critically ill patients: where is the evidence?

PURPOSE OF REVIEW

Ventilator-associated pneumonia (VAP) is a major cause of death, morbidity and costs in ICUs. Several evidence-based clinical interventions have been increasingly described for its prevention. However, continuous control of tracheal cuff pressure (Pcuff) is rarely mentioned in the latest clinical guidelines. This review focuses on the available data about the management of Pcuff in the ICU, including discontinuous and continuous control, and its impact on the prevention of VAP.

RECENT FINDINGS

Current discontinuous monitoring and adjustment of Pcuff, even well performed, is inaccurate in maintaining Pcuff in the target range. Underinflation (Pcuff<20 cmH2O) of tracheal cuff is an independent risk factor for VAP through microaspiration of contaminated subglottic secretions into the lower respiratory tract. Two main types of devices, electronic and pneumatic, have been developed for the continuous control of Pcuff. Both have shown effectiveness in maintaining Pcuff in recommended range in ICU patients, but only the pneumatic device has provided a reduction in microaspiration and VAP incidence.

SUMMARY

Continuous controllers of Pcuff represent effective, easy to use and timesaving devices in today's busy ICU environment. However, further studies are required to determine the impact of continuous control of Pcuff on VAP incidence, patient outcomes, antimicrobial consumption and to compare pneumatic and electronic devices, before generalizing their use in routine practice.

Accuracy of alpha amylase in diagnosing microaspiration in intubated critically-ill patients

OBJECTIVES

Amylase concentration in respiratory secretions was reported to be a potentially useful marker for aspiration and pneumonia. The aim of this study was to determine accuracy of α-amylase in diagnosing microaspiration in critically ill patients.

METHODS

Retrospective analysis of prospectively collected data collected in a medical ICU. All patients requiring mechanical ventilation for at least 48 h, and included in a previous randomized controlled trial were eligible for this study, provided that at least one tracheal aspirate was available for α-amylase measurement. As part of the initial trial, pepsin was quantitatively measured in all tracheal aspirates during a 48-h period. All tracheal aspirates were frozen, allowing subsequent measurement of α-amylase for the purpose of the current study. Microaspiration was defined as the presence of at least one positive tracheal aspirate for pepsin (>200 ng.mL-1). Abundant microaspiration was defined as the presence of pepsin at significant level in >74% of tracheal aspirates.

RESULTS

Amylase was measured in 1055 tracheal aspirates, collected from 109 patients. Using mean α-amylase level per patient, accuracy of α-amylase in diagnosing microaspiration was moderate (area under the receiver operator curve 0.72±0.05 [95%CI 0.61-0.83], for an α-amylase value of 1685 UI.L-1). However, when α-amylase levels, coming from all samples, were taken into account, area under the receiver operator curve was 0.56±0.05 [0.53-0.60]. Mean α-amylase level, and percentage of tracheal aspirates positive for α-amylase were significantly higher in patients with microaspiration, and in patients with abundant microaspiration compared with those with no microaspiration; and similar in patients with microaspiration compared with those with abundant microaspiration. α-amylase and pepsin were significantly correlated (r2 = 0.305, p = 0.001).

CONCLUSION

Accuracy of mean α-amylase in diagnosing microaspiration is moderate. Further, when all α-amylase levels were taken into account, α-amylase was inaccurate in diagnosing microaspiration, compared with pepsin.

Optimal care and design of the tracheal cuff in the critically ill patient

Despite the increasing use of non-invasive ventilation and high-flow nasal-oxygen therapy, intubation is still performed in a large proportion of critically ill patients. The aim of this narrative review is to discuss recent data on long-term intubation-related complications, such as microaspiration, and tracheal ischemic lesions. These complications are common in critically ill patients, and are associated with substantial morbidity and mortality. Recent data suggest beneficial effects of tapered cuffed tracheal tubes in reducing aspiration. However, clinical data are needed in critically ill patients to confirm this hypothesis. Polyurethane-cuffed tracheal tubes and continuous control of cuff pressure could be beneficial in preventing microaspiration and ventilator-associated pneumonia (VAP). However, large multicenter studies are needed before recommending their routine use. Cuff pressure should be maintained between 20 and 30 cmH₂O to prevent intubation-related complications. Tracheal ischemia could be prevented by manual or continuous control of cuff pressure.

Open Tracheostomy after Aborted Percutaneous Approach due to Tracheoscopy Revealing Occult Tracheal Wall Ulcer

Tracheostomy is a common procedure for intensive care patients requiring prolonged mechanical ventilation. In this case report, we describe a 78-year-old female patient admitted for an aneurysm of the cerebral anterior communicating artery. Following immediate endovascular coiling, she remained ventilated and was transferred to the neurological intensive care unit. On postoperative day ten, a percutaneous tracheostomy (PCT) was requested; however, a large ulcer or possible tracheoesophageal fistula was identified on the posterior tracheal wall following bronchoscopic assessment of the trachea. Therefore, the requested PCT procedure was aborted. An open tracheostomy in the operating room was completed; however, due to the position and depth of the ulcer, a reinforced endotracheal tube (ETT) was placed via the tracheostomy. Four days later, the reinforced ETT was replaced with a Shiley distal extended tracheostomy tube to bypass the ulceration. Careful inspection and evaluation of the tracheostomy site before PCT prevented a potentially life-threatening issue in our patient.