Complications of assisted ventilation. A prospective study of 354 consecutive episodes

Predictors for postoperative dysphagia in liver transplant recipients

Introduction

Liver transplant recipients are at a heightened risk for oropharyngeal dysphagia; identification of those who are at high risk for postoperative dysphagia could reduce hospital costs and length of stay. We sought to identify predictors of dysphagia, in a large cohort of patients who underwent liver transplantation.

Methods

Electronic medical records were queried for patients undergoing liver transplantation, who underwent instrumental swallowing evaluations. Demographics, functional outcomes, and interventions were collected. Logistic regression analyses were performed to identify predictors of dysphagia.

Results

Seven hundred and ninety-five patients met inclusionary criteria. Multivariate analyses found ethnic group (p = .0191), MELD Score (p < 0001), cold ischemia time (p = .0123), and length of intubation (p < .0001) to be predictors of post-operative development of dysphagia. Pre-transplant dialysis (p < .0001), dysphagia related to end stage liver disease (p < .0001), Karnofsky Performance Status Scale (p < .0001), wait time to transplant (p = 0.0173), surgery time (p = 0.0095), tracheostomy (p < 0.0001), and transfusion of intraoperative RBC (p < .0001), intraoperative platelets (p = 0.0018), intraoperative FFP (p = 0.0495), perioperative FFP (p = 0.0002), perioperative platelets (p = 0.0151) and perioperative RBC (p = 0.0002) were variables of significance associated with the development of postoperative dysphagia from univariate analysis.

Conclusions

Our results propose a set of predictors that should be considered when identifying post-operative critically ill patients at risk for dysphagia.

Pulmonary Physiology and Medicine of Diving

Pulmonary physiology is significantly altered during underwater exposure, as immersion of the body and increased ambient pressure elicit profound effects on both the cardiovascular and respiratory systems. Thoracic blood pooling, increased breathing gas pressures, and variations in gas volumes alongside ambient pressure changes put the heart and lungs under stress. Normal physiologic function and fitness of the cardiovascular and respiratory systems are prerequisites to safely cope with the challenges of the underwater environment when freediving, or diving with underwater breathing apparatus. Few physicians are trained to understand the physiology and medicine of diving and how to recognize or manage diving injuries. This article provides an overview of the physiologic challenges to the respiratory system during diving, with or without breathing apparatus, and outlines possible health risks and hazards unique to the underwater environment. The underlying pathologic mechanisms of dive-related injuries are reviewed, with an emphasis on pulmonary physiology and pathophysiology.

Position Classification of the Endotracheal Tube with Automatic Segmentation of the Trachea and the Tube on Plain Chest Radiography Using Deep Convolutional Neural Network

Background: This study aimed to develop an algorithm for multilabel classification according to the distance from carina to endotracheal tube (ETT) tip (absence, shallow > 70 mm, 30 mm ≤ proper ≤ 70 mm, and deep position < 30 mm) with the application of automatic segmentation of the trachea and the ETT on chest radiographs using deep convolutional neural network (CNN). Methods: This study was a retrospective study using plain chest radiographs. We segmented the trachea and the ETT on images and labeled the classification of the ETT position. We proposed models for the classification of the ETT position using EfficientNet B0 with the application of automatic segmentation using Mask R-CNN and ResNet50. Primary outcomes were favorable performance for automatic segmentation and four-label classification through five-fold validation with segmented images and a test with non-segmented images. Results: Of 1985 images, 596 images were manually segmented and consisted of 298 absence, 97 shallow, 100 proper, and 101 deep images according to the ETT position. In five-fold validations with segmented images, Dice coefficients [mean (SD)] between segmented and predicted masks were 0.841 (0.063) for the trachea and 0.893 (0.078) for the ETT, and the accuracy for four-label classification was 0.945 (0.017). In the test for classification with 1389 non-segmented images, overall values were 0.922 for accuracy, 0.843 for precision, 0.843 for sensitivity, 0.922 for specificity, and 0.843 for F1-score. Conclusions: Automatic segmentation of the ETT and trachea images and classification of the ETT position using deep CNN with plain chest radiographs could achieve good performance and improve the physician’s performance in deciding the appropriateness of ETT depth.

Clinical impact of pneumothorax in patients with Pneumocystis jirovecii pneumonia and respiratory failure in an HIV-negative cohort

Background

Pneumocystis jirovecii pneumonia (PCP) with acute respiratory failure can result in development of pneumothorax during treatment. This study aimed to identify the incidence and related factors of pneumothorax in patients with PCP and acute respiratory failure and to analyze their prognosis.

Methods

We retrospectively reviewed the occurrence of pneumothorax, including clinical characteristics and results of other examinations, in 119 non-human immunodeficiency virus patients with PCP and respiratory failure requiring mechanical ventilator treatment in a medical intensive care unit (ICU) at a tertiary-care center between July 2016 and April 2019.

Results

During follow up duration, twenty-two patients (18.5%) developed pneumothorax during ventilator treatment, with 45 (37.8%) eventually requiring a tracheostomy due to weaning failure. Cytomegalovirus co-infection (odds ratio 13.9; p = 0.013) was related with occurrence of pneumothorax in multivariate analysis. And development of pneumothorax was not associated with need for tracheostomy and mortality. Furthermore, analysis of survivor after 28 days in ICU, patients without pneumothorax were significantly more successful in weaning from mechanical ventilator than the patients with pneumothorax (44% vs. 13.3%, p = 0.037). PCP patients without pneumothorax showed successful home discharges compared to those who without pneumothorax (p = 0.010).

Conclusions

The development of pneumothorax increased in PCP patient with cytomegalovirus co-infection, pneumothorax might have difficulty in and prolonged weaning from mechanical ventilators, which clinicians should be aware of when planning treatment for such patients.

Repeated endotracheal tube cuff tears during nasotracheal intubation due to nasal cavity orthodontic micro-implant - A case report

Background

Nasotracheal intubation is generally performed for intraoral surgery.

Case

A 34-year-old female patient who underwent orthognathic surgery exhibited repeated endotracheal tube cuff tears during nasotracheal intubation. After intubation, leaks developed, and torn endotracheal cuff was observed in the removed endotracheal tube. Subsequently, re-intubation through the same nasal cavity was performed immediately, but leakage from the torn endotracheal tube cuff was re-observed. A leakage test of the extubated tube revealed air bubbles and leaks near the tube cuff due to the tear. Nasotracheal intubation was performed through the other nasal cavity, and there were no leakage findings or abnormalities. During the course of the surgery, the surgeon noticed that the orthodontic micro-implant deposited in the mid-tube cavity was exposed to the nasal cavity.

Conclusions

We aimed to emphasize caution and discuss the possibility that orthodontic micro-implants that are not confirmed during preoperative evaluation may cause repeated endotracheal tube cuff tears.

Endotracheal Tube Position Assessment on Chest Radiographs Using Deep Learning

PURPOSE

To determine the efficacy of deep learning in assessing endotracheal tube (ETT) position on radiographs.

MATERIALS AND METHODS

In this retrospective study, 22 960 de-identified frontal chest radiographs from 11 153 patients (average age, 60.2 years ± 19.9 [standard deviation], 55.6% men) between 2010 and 2018 containing an ETT were placed into 12 categories, including bronchial insertion and distance from the carina at 1.0-cm intervals (0.0-0.9 cm, 1.0-1.9 cm, etc), and greater than 10 cm. Images were split into training (80%, 18 368 images), validation (10%, 2296 images), and internal test (10%, 2296 images), derived from the same institution as the training data. One hundred external test radiographs were also obtained from a different hospital. The Inception V3 deep neural network was used to predict ETT-carina distance. ETT-carina distances and intraclass correlation coefficients (ICCs) for the radiologists and artificial intelligence (AI) system were calculated on a subset of 100 random internal and 100 external test images. Sensitivity and specificity were calculated for low and high ETT position thresholds.

RESULTS

On the internal and external test images, respectively, the ICCs of AI and radiologists were 0.84 (95% CI: 0.78, 0.92) and 0.89 (95% CI: 0.77, 0.94); the ICCs of the radiologists were 0.93 (95% CI: 0.90, 0.95) and 0.84 (95% CI: 0.71, 0.90). The AI model was 93.9% sensitive (95% CI: 90.0, 96.7) and 97.7% specific (95% CI: 96.9, 98.3) for detecting ETT-carina distance less than 1 cm.

CONCLUSION

Deep learning predicted ETT-carina distance within 1 cm in most cases and showed excellent interrater agreement compared with radiologists. The model was sensitive and specific in detecting low ETT positions.© RSNA, 2020.

An observational study to determine whether alignment of endotracheal tube indicator line with the vocal cords results in appropriate depth of intubation

Background: Inappropriate endotracheal tube placement depth may be associated with complications. Objective: To determine whether the accurate alignment of the indicator ring on the endotracheal tube at the level of the vocal cords, results in its appropriate placement. Design: Prospective observational study. Patients: 98 adult patients scheduled for general anesthesia with orotracheal intubation. Interventions: The indicator band mark on the endotracheal tube was accurately placed at the vocal cords level under video-laryngoscope view. The tube length at the right upper incisor and the distance between its tip and the carina was measured using fibreoptic bronchoscope. Data to validate methods to predict insertion depth was collected and evaluated. Main Outcome: To determine the distance between the tip of the endotracheal tube and the carina. Results: The endotracheal tube tip depth was inap- propriate in 46.94% cases and was <3 cm above the carina in 41.64% cases. This difference in this distance was similar (p = 0.246) in the two genders. A correlation was noted between topographic length and insertion depth in females only (r2 = 0.201 and p = 0.001). The mean tracheal length was 12.66 + 1.35 cm in males and 12.04 + 1.26 cm in females. Conclusion: We found a high incidence of endo- tracheal tube tip malposition despite the accurate placement of the indicator band at the vocal cords level. We suggest that international endotracheal tube design standards be defined and endotracheal tube manufacturers modify the standard intratracheal length.

Descriptive Analysis of Extubations Performed in an Emergency Department-based Intensive Care Unit

Introduction

Extubation of appropriate patients in the emergency department (ED) may be a strategy to avoid preventable or short-stay intensive care unit (ICU) admissions, and could allow for increased ventilator and ICU bed availability when demand outweighs supply. Extubation is infrequently performed in the ED, and a paucity of outcome data exists. Our objective was to descriptively analyze characteristics and outcomes of patients extubated in an ED-ICU setting.

Methods

We conducted a retrospective observational study at an academic medical center in the United States. Adult ED patients extubated in the ED-ICU from 2015–2019 were retrospectively included and analyzed.

Results

We identified 202 patients extubated in the ED-ICU; 42% were female and median age was 60.86 years. Locations of endotracheal intubation included the ED (68.3%), outside hospital ED (23.8%), and emergency medical services/prehospital (7.9%). Intubations were performed for airway protection (30.2%), esophagogastroduodenoscopy (27.7%), intoxication/ingestion (17.3%), respiratory failure (13.9%), seizure (7.4%), and other (3.5%). The median interval from ED arrival to extubation was 9.0 hours (interquartile range 6.2–13.6). One patient (0.5%) required unplanned re-intubation within 24 hours of extubation. The attending emergency physician (EP) at the time of extubation was not critical care fellowship trained in the majority (55.9%) of cases. Sixty patients (29.7%) were extubated compassionately; 80% of these died in the ED-ICU, 18.3% were admitted to medical-surgical units, and 1.7% were admitted to intensive care. Of the remaining patients extubated in the ED-ICU (n = 142, 70.3%), zero died in the ED-ICU, 61.3% were admitted to medical-surgical units, 9.9% were admitted to intensive care, and 28.2% were discharged home from the ED-ICU.

Conclusion

Select ED patients were safely extubated in an ED-ICU by EPs. Only 7.4% required ICU admission, whereas if ED extubation had not been pursued most or all patients would have required ICU admission. Extubation by EPs of appropriately screened patients may help decrease ICU utilization, including when demand for ventilators or ICU beds is greater than supply. Future research is needed to prospectively study patients appropriate for ED extubation.

Dual Carbon Dioxide Capture to Achieve Highly Efficient Ultra-Low Blood Flow Extracorporeal Carbon Dioxide Removal

Extracorporeal CO₂ removal is a highly promising support therapy for patients with hypercapnic respiratory failure but whose clinical implementation and patient benefit is hampered by high cost and highly specialized expertise required for safe use. Current approaches target removal of the gaseous CO₂ dissolved in blood which limits their ease of clinical use as high blood flow rates are required to achieve physiologically significant CO₂ clearance. Here, a novel hybrid approach in which a zero-bicarbonate dialysis is used to target removal of bicarbonate ion coupled to a gas exchange device to clear dissolved CO₂, achieves highly efficiently total CO₂ capture while maintaining systemic acid-base balance. In a porcine model of acute hypercapnic respiratory failure, a CO₂-reduction of 61.4 ± 14.4 mL/min was achieved at a blood flow rate of 248 mL/min using pediatric-scale priming volumes. The dialyzer accounted for 81% of total CO₂ capture with an efficiency of 33% with a minimal pH change across the entire circuit. This study demonstrates the feasibility of a novel hybrid CO₂ capture approach capable of achieving physiologically significant CO₂ removal at ultralow blood flow rates with low priming volumes while leveraging widely available dialysis platforms to enable clinical adoption.

Emergent airway management outside of the operating room - a retrospective review of patient characteristics, complications and ICU stay

Background

Emergent airway management outside of the operating room is a high-risk procedure. Limited data exists about the indication and physiologic state of the patient at the time of intubation, the location in which it occurs, or patient outcomes afterward.

Methods

We retrospectively collected data on all emergent airway management interventions performed outside of the operating room over a 6-month period. Documentation included intubation performance, and intubation related complications and mortality. Additional information including demographics, ASA-classification, comorbidities, hospital-stay, ICU-stay, and 30-day in-hospital mortality was obtained.

Results

336 intubations were performed in 275 patients during the six-month period. The majority of intubations (n = 196, 58%) occurred in an ICU setting, and the rest 140 (42%) occurred on a normal floor or in a remote location. The mean admission ASA status was 3.6 ± 0.5, age 60 ± 16 years, and BMI 30 ± 9 kg/m². Chest X-rays performed immediately after intubation showed main stem intubation in 3.3% (n = 9). Two immediate (within 20 min after intubation) intubation related cardiac arrest/mortality events were identified. The 30-day in-hospital mortality was 31.6% (n = 87), the overall in-hospital mortality was 37.1% (n = 102), the mean hospital stay was 22 ± 20 days, and the mean ICU-stay was 14 days (13.9 ± 0.9, CI 12.1–15.8) with a 7.3% ICU-readmission rate.

Conclusion

Patients requiring emergent airway management are a high-risk patient population with multiple comorbidities and high ASA scores on admission. Only a small number of intubation-related complications were reported but ICU length of stay was high.

“A-OK”: Chest Radiograph during Primary Survey Facilitates Faster, More Accurate Endotracheal Tube Position in Injured Children

The Advanced Trauma Life Support algorithm recommends bedside confirmatory techniques to confirm correct endotracheal tube (ETT) depth, a critical component in the care of pediatric trauma patients. We hypothesized that bedside confirmatory techniques are inaccurate and that early chest X-ray (CXR) would overcome such inaccuracies, allowing for faster intervention of malpositioned ETTs. An “A-OK” algorithm of immediate CXR following intubation in injured children aged <16 years was implemented. Eligible patients the years before and after implementation were identified. The accuracy of bedside confirmatory techniques (use of length-based depths and auscultation of breath sounds) was assessed. Post-“A-OK” patients were compared with pre-“A-OK” controls regarding the speed of malpositioned ETTrepositioning. Twenty-eight post-“A-OK” cases and 23 pre-“A-OK” controls were identified. The groups did not differ in baseline characteristics. Bedside confirmatory techniques were accurate in only 61 per cent (length-based depth) and 58 per cent (auscultation of breath sounds) of patients. Time to ETT repositioning was significantly longer in pre-“A-OK” controls than in post-“A-OK” cases (35.2 ± 15.9 minutes vs 21.1 ± 11.8 minutes, P = 0.03). Bedside confirmatory techniques to determine ETT positioning are inaccurate in children. Inclusion of CXR in the primary survey is safe and allows for more rapid repositioning of malpositioned ETTs.

Insertion depth of nasotracheal tubes sized to fit the nostril: an observational study

Objective

Nasotracheal (NT) intubation is commonly applied during head and neck surgery. However, improper tube size and depth may cause complications. In the current study, we investigated whether NT tubes are being appropriately used in terms of size and depth in adult patients.

Methods

Nares were sized in 40 patients using standard nasopharyngeal airways (6.0–8.0) before elective surgery under general anesthesia. The largest sized airway that passed easily into the nasopharynx without resistance was considered as a proper size. Using a fiberoptic scope, the distances from the nares to the vocal cords and the nares to the carina were measured. Rates of proper NT tube positioning were calculated with regard to the cuff and distal tip.

Results

The most frequent sizes of properly fitted NT tubes were 6.5 and 6.0 in male and female patients, respectively. Positioning of the cuff and distal tip was only appropriate when using a properly sized tube in 26% and 47% of male and female patients, respectively.

Conclusion

Care should be taken to determine the insertion depth after placing an NT tube that has been sized to fit the nostril. Moreover, NT tubes of the same diameter may be required in various lengths.

Trial registration: Registered at ClinicalTrial.gov; https://clinicaltrials.gov/ct2/show/NCT02876913; Registration number NCT02876913

Outcome of invasive mechanical ventilation in cancer patients: Intubate or not to intubate a patient with cancer

PURPOSE

The outcome of cancer patients who undergo mechanical ventilation has been grim. However, it has lately become more promising, creating hesitation when approaching the decision to intubate a cancer patient. Therefore, the main goal was to find some factors that could predict mortality.

MATERIAL AND METHODS

Studies were selected on the basis of their information wholeness, the year done, patients' number, participating country, underlying hematological or nonhematological malignancies, ventilation duration, ICU survival, hospital survival, long term survival, disease activity, and other contributing factors.

RESULTS

Twenty-two studies were included which accrued 3115 patients. The average ICU survival was 32.4%, and long-term survival was 10.2%. Over the years, the outcome of cancer patients undergoing mechanical ventilation has improved. The most important predicting factors are: The respiratory failure etiology, the performance status, the disease activity, and the SOFA score.

CONCLUSIONS

The aforementioned predicting factors could be used when approaching the decision to intubate. When in doubt, we should give the benefit to the patient, proceed to intubate and reevaluate progress daily and in doing so, we would suggest to use the trends in SOFA score and weaning index to assess success or failure of invasive mechanical ventilation.

A multi-center evaluation of a disposable catheter to aid in correct positioning of the endotracheal tube after intubation in critically ill patients

PURPOSE

To demonstrate that use of a minimally invasive catheter reduces endotracheal tube (ETT) malposition rate after intubation.

MATERIALS AND METHODS

This study is a multi-center, prospective observational cohort of intubated patients in the medical intensive care unit. The catheter was inserted into the ETT immediately after intubation. The ETT was adjusted accordingly based on qualitative color markers on the catheter. A confirmatory chest radiograph was obtained to determine the ETT position. Malposition of the ETT was defined by the distal ETT not being within 2-5 cm above the carina.

RESULTS

Sixty-nine patients were enrolled, age 56.2 ± 19.5 years, body mass index 31.0 ± 13.8 kg/m². The catheter prompted repositioning of the ETT in 39 (56.5%) patients. Using the catheter, the rate of malposition decreased to 7.2%, with the distal ETT position at 3.7 ± 1.2 cm above the carina. Without the catheter, the ETT malposition rate would have been 39.1%. The time for catheter use and chest radiograph completion at our institutions was 1.7 ± 1.5 and 44.4 ± 36.4 min, respectively.

CONCLUSIONS

With use of an ETT positioning catheter after intubation, the ETT malposition rate was reduced by 82%. This catheter-based system was safe, and its use may perhaps decrease the need for the post-intubation chest radiograph.

Non-invasive ventilation in cardiogenic pulmonary edema

Cardiogenic pulmonary edema (CPE) is among the most common causes of acute respiratory failure (ARF) in the acute care setting and often requires ventilatory assistance. In patients with ARF due to CPE, use of non-invasive positive airway pressure can decrease the systemic venous return and the left ventricular (LV) afterload, thus reducing LV filling pressure and limiting pulmonary edema. In these patients, either non-invasive ventilation (NIV) or continuous positive airway pressure (CPAP) can improve vital signs and physiological parameters, decreasing the need for endotracheal intubation (ETI) and hospital mortality when compared to conventional oxygen therapy. Results on the use of NIV or CPAP in patients with CPE prior to hospitalization are not homogeneous among studies, hampering any conclusive recommendation regarding their role in the pre-hospital setting.

Team-based model for non-operating room airway management: validation using a simulation-based study

BACKGROUND

Non-operating room (non-OR) airway management has previously been identified as an area of concern because it carries a significant risk for complications. One reason for this could be attributed to the independent practice of residents in these situations. The aim of the present study was to ascertain whether differences in performance exist between residents working alone vs with a resident partner when encountering simulated non-OR airway management scenarios.

METHODS

Thirty-six anaesthesia residents were randomized into two groups. Each group experienced three separate scenarios (two scenarios initially and then a third 6 weeks later). The scenarios consisted of one control scenario and two critical event scenarios [i.e. asystole during laryngoscopy and pulseless electrical activity (PEA) upon post-intubation institution of positive pressure ventilation]. One group experienced the simulated non-OR scenarios alone (Solo group). The other group consisted of resident pairs, participating in the same three scenarios (Team group).

RESULTS

Although the time to intubation did not differ between the Solo and Team groups, there were several differences in performance. The Team group received better overall performance ratings for the asystole (8.5 vs 5.5 out of 10; P<0.001) and PEA (8.5 vs 5.8 out of 10; P<0.001) scenarios. The Team group was also able to recognize asystole and PEA conditions faster than the Solo group [10.1 vs 23.5 s (P<0.001) and 13.3 vs 36.0 s (P<0.001), respectively].

CONCLUSIONS

Residents who performed a simulated intubation with a second trained provider had better overall performance than those who practised independently. The residents who practised in a group were also faster to diagnose serious complications, including peri-intubation asystole and PEA. Given these data, it is reasonable that training programmes consider performing all non-OR airway management with a team-based method.

Deep Convolutional Neural Networks for Endotracheal Tube Position and X-ray Image Classification: Challenges and Opportunities

The goal of this study is to evaluate the efficacy of deep convolutional neural networks (DCNNs) in differentiating subtle, intermediate, and more obvious image differences in radiography. Three different datasets were created, which included presence/absence of the endotracheal (ET) tube (n = 300), low/normal position of the ET tube (n = 300), and chest/abdominal radiographs (n = 120). The datasets were split into training, validation, and test. Both untrained and pre-trained deep neural networks were employed, including AlexNet and GoogLeNet classifiers, using the Caffe framework. Data augmentation was performed for the presence/absence and low/normal ET tube datasets. Receiver operating characteristic (ROC), area under the curves (AUC), and 95% confidence intervals were calculated. Statistical differences of the AUCs were determined using a non-parametric approach. The pre-trained AlexNet and GoogLeNet classifiers had perfect accuracy (AUC 1.00) in differentiating chest vs. abdominal radiographs, using only 45 training cases. For more difficult datasets, including the presence/absence and low/normal position endotracheal tubes, more training cases, pre-trained networks, and data-augmentation approaches were helpful to increase accuracy. The best-performing network for classifying presence vs. absence of an ET tube was still very accurate with an AUC of 0.99. However, for the most difficult dataset, such as low vs. normal position of the endotracheal tube, DCNNs did not perform as well, but achieved a reasonable AUC of 0.81.

New decision formulas for predicting endotracheal tube depth in children: analysis of neck CT images

INTRODUCTION

The purpose of this study was to construct a prediction model for endotracheal tube depth using neck CT images.

METHODS

A retrospective image review was conducted that included patients who had undergone neck CT. Using sagittal neck CT images, we calculated the length between upper incisor and mid-trachea and then derived the model via regression analysis. The model was validated externally using chest radiographs of patients who had undergone endotracheal intubation. We compared performance of our model with that of other methods (Broselow tape and APLS formula) via Bland-Altman analysis and the percentage of estimations within 10% of the measured values.

RESULTS

A total of 1111 children were included in this study. The tube depth obtained from CT images was linearly related to body weight (tube depth (cm)=5.5+0.5×body wt (kg)) in children younger than 1 year and to height (tube depth (cm)=3+0.1×height (cm)) in children older than 1 year. External validation demonstrated that our new model showed better agreement with the desired tube depth than Broselow tape and APLS formula. The mean differences in children younger than 1 year were 0.61 cm and -1.24 cm for our formula and Broselow tape, respectively. The mean differences in children older than 1 year were -0.43 cm, -1.98 and -1.64 cm for our formula, Broselow tape and APLS formula, respectively. The percentages of estimates within 10% of the measured values were 52.7% and 35.8% for our formula and Broselow tape in children younger than 1 year, respectively, and 54.3%, 33.8% and 37.2% for our formula, Broselow tape and APLS formula in children older than 1 year, respectively (P<0.01).

CONCLUSION

Our new formula is useful and more accurate than the currently available methods.

Estimation of optimal nasotracheal tube depth in adult patients

Background

The aim of this study was to estimate the optimal depth of nasotracheal tube placement.

Methods

We enrolled 110 patients scheduled to undergo oral and maxillofacial surgery, requiring nasotracheal intubation. After intubation, the depth of tube insertion was measured. The neck circumference and distances from nares to tragus, tragus to angle of the mandible, and angle of the mandible to sternal notch were measured. To estimate optimal tube depth, correlation and regression analyses were performed using clinical and anthropometric parameters.

Results

The mean tube depth was 28.9 ± 1.3 cm in men (n = 62), and 26.6 ± 1.5 cm in women (n = 48). Tube depth significantly correlated with height (r = 0.735, P < 0.001). Distances from nares to tragus, tragus to angle of the mandible, and angle of the mandible to sternal notch correlated with depth of the endotracheal tube (r = 0.363, r = 0.362, and r = 0.546, P < 0.05). The tube depth also correlated with the sum of these distances (r = 0.646, P < 0.001). We devised the following formula for estimating tube depth: 19.856 + 0.267 × sum of the three distances (R² = 0.432, P < 0.001).

Conclusion

The optimal tube depth for nasotracheally intubated adult patients correlated with height and sum of the distances from nares to tragus, tragus to angle of the mandible, and angle of the mandible to sternal notch. The proposed equation would be a useful guide to determine optimal nasotracheal tube placement.

Loxapine to control agitation during weaning from mechanical ventilation

Background

Weaning from mechanical ventilation (MV) may be impeded by the occurrence of agitation. Loxapine has the ability to control agitation without affecting spontaneous ventilation. The aim of this study was to establish whether loxapine would reduce MV weaning duration in agitated patients.

Methods

We performed a multicentre, double-blind, placebo-controlled, parallel group, randomised trial. Patients who were potential candidates for weaning but exhibited agitation (Richmond Agitation-Sedation Scale score ≥ 2) after sedation withdrawal were randomly assigned to receive either loxapine or placebo. In case of severe agitation, conventional sedation was immediately resumed. The primary endpoint was the time between first administration of loxapine or placebo and successful extubation.

Results

The trial was discontinued after 102 patients were enrolled because of an insufficient inclusion rate. Median times to successful extubation were 3.2 days in the loxapine group and 5 days in the placebo group (relative risk 1.2, 95% CI 0.75–1.88, p = 0.45). During the first 24 h, sedation was more frequently resumed in the placebo group (44% vs 17%, p = 0.01).

Conclusions

In this prematurely stopped trial, loxapine did not significantly shorten weaning from MV. However, loxapine reduced the need for resuming sedation.

Trial registration

Clinicaltrials.gov, NCT01193816. Registered on 26 August 2010.

Adherence to Evidence-Base Endotracheal Intubation Practice Patterns by Intensivists and Emergency Department Physicians

BACKGROUND

Endotracheal intubation outside the operating room (OR) is mainly performed by intensive care (IC) physicians and emergency department (ED) physicians. We hypothesized that difference in practice patterns exists between these two groups of physicians.

METHODS

A retrospective chart review was performed on all endotracheal intubations that were performed out of OR over a fi ve year period at our health care facility. Practice patterns of IC and ED physicians were compared regarding use of (a) video laryngoscopy, (b) paralytic agents, (c) waveform capnography, and (d) use of larger size of endotracheal tube (internal diameter ≥ 8 mm).

RESULTS

A total of 201 patients underwent out of OR intubations over a 5 year period. IC physicians used more often than ED physicians video laryngoscopy (67% vs. 49%; p = 0.008), waveform capnography (99% vs. 86%; p = 0.001) and larger size endotracheal tubes (95% vs. 60%; p < 0.001). Conversely, paralytic agents were used less frequently by IC than ED physicians (12% vs. 51%; p < 0.001). The success of fi rst intubation attempt was higher by IC than ED physicians (82% vs. 67%; p = 0.018).

CONCLUSIONS

IC physicians more often adhered to currently considered preferable practices for endotracheal intubation than ED physicians in this single center retrospective study. Although larger scale studies are needed to unveil the effects of different practice patterns on short and long term outcomes, the present study identifi es opportunity to bridge practice gaps that could lead to improved outcomes.

Pneumothorax Related to Mechanical Ventilation: Silent Enemy

Pneumothorax is well known and described complication in intensive care unit patients (ICU). Incidence of this complication is higher in patients with underlying pathology. As it can be occult, it is of the most importance to think of it in patients on mechanical ventilation. In this case report we well present ventilator-related pneumothorax in infant: clinical presentation, diagnosis and management

Analytic Reviews : Initiating Mechanical Ventilation

Mechanical ventilation is a central facet of intensive care medicine. Technological progress has led to major advances in this field. Initiation of mechanical ventila tion remains standard; however, many options are now available to continue mechanical ventilation. These mechanical options include assist-control ventilation, intermittent mandatory ventilation, pressure support ventilation, positive end-expiratory pressure, and high- frequency ventilation. The sophistication of ventilators has also allowed more procedures to be performed dur ing mechanical ventilation, including bronchoscopy and transbronchial biopsy. Complications do occur during mechanical ventilation, but can be minimized by vigi lance and use of proper procedures. The recent increase in home care will lead to increased use of alternatives to conventional ventilatory modes. Finally, more well- designed studies are needed as newer techniques are promoted.

Radiology in the Intensive Care Unit (Part 2)

This review of intensive care unit (ICU) radiology has been divided into two sections. In Part 1, previously published, the discussion focused on the role of the portable radiograph in the evaluation of the critically ill patient and the impact of the introduction of digital radiography and picture-archiving communications systems on patient care. Part 2 of this review will emphasize the role of computed tomography and the increasing contribution of image-guided interventional procedures in patient management. The deleterious effects of mechanical ventilation due to barotrauma will also be discussed.

Pulmonary Barotrauma in the Intensive Care Unit

Disruption of lung parenchyma by airway gas (baro trauma) frequently occurs in the intensive care unit. Gas may move from the airspace into several abnormal loca tions as a result of dissection along anatomical fascial planes to potentially produce interstitial emphysema, subpleural cysts, pneumomediastinum, subcutaneous emphysema, pneumopericardium, pneumothorax, pneu moperitoneum, pneumoretroperitoneum, bronchopleu ral fistulas, and air-entry into blood vessels. Although usually of limited clinical consequence, this extra-alve olar air may produce clinically significant morbidity and mortality. Recognition of these potential complications of pulmonary disease and its therapy may assist the clini cian in correctly diagnosing, avoiding, and treating the manifestations of pulmonary barotrauma.

Iatrogenic pneumothorax related to mechanical ventilation

Pneumothorax is a potentially lethal complication associated with mechanical ventilation. Most of the patients with pneumothorax from mechanical ventilation have underlying lung diseases; pneumothorax is rare in intubated patients with normal lungs. Tension pneumothorax is more common in ventilated patients with prompt recognition and treatment of pneumothorax being important to minimize morbidity and mortality. Underlying lung diseases are associated with ventilator-related pneumothorax with pneumothoraces occurring most commonly during the early phase of mechanical ventilation. The diagnosis of pneumothorax in critical illness is established from the patients’ history, physical examination and radiological investigation, although the appearances of a pneumothorax on a supine radiograph may be different from the classic appearance on an erect radiograph. For this reason, ultrasonography is beneficial for excluding the diagnosis of pneumothorax. Respiration-dependent movement of the visceral pleura and lung surface with respect to the parietal pleura and chest wall can be easily visualized with transthoracic sonography given that the presence of air in the pleural space prevents sonographic visualization of visceral pleura movements. Mechanically ventilated patients with a pneumothorax require tube thoracostomy placement because of the high risk of tension pneumothorax. Small-bore catheters are now preferred in the majority of ventilated patients. Furthermore, if there are clinical signs of a tension pneumothorax, emergency needle decompression followed by tube thoracostomy is widely advocated. Patients with pneumothorax related to mechanical ventilation who have tension pneumothorax, a higher acute physiology and chronic health evaluation II score or PaO₂/FiO₂ < 200 mmHg were found to have higher mortality.

Endotracheal tube cuff leaks: causes, consequences, and management

The consequences of endotracheal tube (ETT) cuff leak may range from a bubbling noise to a life-threatening ventilatory failure. Although the definitive solution is ETT replacement, this is often neither needed nor safe to perform. Frequently, the leak is not caused by a structural defect in the ETT. Cuff underinflation, cephalad migration of the ETT (partial tracheal extubation), misplaced orogastric or nasogastric tubes, wide discrepancy between ETT and tracheal diameters, or increased peak airway pressure can cause leaks around intact cuffs. Correction of these problems will stop the leak without ETT replacement. Alternatively, ETT cuff, pilot balloon, and inflation system damage due to inadvertent trauma or manufacturing defects may be responsible. Conservative management ideas (management without ETT replacement) were previously published to solve the problem. However, when a large structural defect is identified or conservative measures fail, ETT replacement becomes necessary. This can be performed with direct laryngoscopy if laryngeal visualization is adequate. A difficult exchange with possible airway loss should be anticipated, and prepared for, when there are signs and/or history of difficult intubation. A risk/benefit analysis of each individual situation is warranted before decisions are made on how best to proceed. Alternative back-up ventilation plans should be preformulated and the necessary equipment ready before the exchange. In this review, various management concerns and plans are discussed, and a simple algorithm to manage leaky ETT cuff situations is presented.

Polyclonal endemicity of Acinetobacter baumannii in ventilated patients in an intensive care unit in Uruguay

OBJECTIVES

To identify the mechanisms responsible for respiratory infections by Acinetobacter baumannii in intubated patients and risk factors for digestive colonization and infection by A. baumannii.

METHODS

We conducted a prospective study in an intensive care unit (ICU) between May 2005 and November 2006, including 175 consecutive patients at the beginning of invasive ventilation (day 1). We performed pharyngeal and rectal swabs on days 1, 4, 7, 10, 13, and 16. Respiratory samples were taken on days 1 and 7, or on suspicion of ventilator-associated pneumonia (VAP).

RESULTS

We detected 62 patients with A. baumannii digestive colonization and 20 cases of A. baumannii lower respiratory infection (14 VAP and six purulent tracheobronchitis (PTB)). Digestive colonization by A. baumannii was an independent risk factor for lower respiratory tract infections with that microorganism (p<0.0001; relative risk 8.71, 95% confidence interval 2.73-27.77). Respiratory and rectal A. baumannii isolates from the same patients were compared by enterobacterial repetitive intergenic consensus (ERIC)-PCR; in 9/11 cases (eight VAP and one PTB) results suggested events of exogenous pneumonia with previous colonization, whereas the remaining two cases (two PTB) were suggestive of exogenous infection without previous colonization.

CONCLUSIONS

In our unit the pathogenesis of VAP by A. baumannii is mixed, most cases corresponding to exogenous pneumonia with previous colonization.

Comparison of two topographical airway length measurements in adults

Background

A correct estimate of the tracheal tube insertion depth can prevent complications, including endobronchial intubation and vocal cord trauma. We evaluated a new topographical method for endotracheal tube positioning relative to the carina, using a well-known prior topographical method for comparison.

Methods

One hundred adult (male 50, female 50) patients were studied. The comparison topographic length (in cm) was measured by adding the distance between the right mouth corner and the right mandibular angle to the distance between the right mandibular angle and the center of the sternal manubrium. The new endotracheal tube insertion depth (in cm) was determined by adding the distance between the right mouth corner and the vocal cords, measured with the endotracheal tube itself, to the distance between the thyroid prominence and the manubriosternal joint, and then subtracting 4 cm. After intubation, the endotracheal tube was positioned properly at the right mouth corner and the endotracheal tube tip was evaluated using a fiberoptic bronchoscope at the carina.

Results

The distances from the tip of the endotracheal tube to the carina were not significantly different between the methods in the same gender. However, our method allowed endotracheal tube tip placement between 3 cm and 5 cm, above the carina more frequently than the prior method in males.

Conclusions

The new topographical method can be used as a guide to positioning the endotracheal tubes.

Where's the Tube? Evaluation of Hand-held Ultrasound in Confirming Endotracheal Tube Placement

Introduction:

The diagnosis of endotracheal tube (ETT) mal-position may be delayed in extreme environments. Several methods are utilized to confirm proper ETT placement, but these methods can be unreliable or unavailable in certain settings. Thoracic sonography, previously utilized to detect pneumothoraces, has not been tested to assess ETT placement.

Hypothesis:

Thoracic sonography could correlate with pulmonary ventilation, and thereby, help to confirm proper ETT placement.

Methods:

Thirteen patients requiring elective intubation under general anesthesia, and data from two trauma patients were evaluated. Using a portable, hand-held, ultrasound (PHHU) machine, sonographic recordings of the chest wall visceral-parietal pleural interface (VPPI) were recorded bilaterally in each patient during all phases of airway management: (1) preoxygenation; (2) induction; (3) paralysis; (4) intubation; and (5) ventilation. Results: The VPPI could be well-imaged for all of the patients. In the two trauma patients, right mainstem intubations were noted in which specific pleural signals were not seen in the left chest wall VPPI after tube placement. These signs returned after correct repositioning of the ETT tube. In all of the elective surgery patients, signs correlating with bilateral ventilation in each patient were imaged and correlated with confirmation of ETT placement by anesthesiology.

Conclusions:

This report raises the possibility that thoracic sonography may be another tool that could be used to confirm proper ETT placement. This technique may have merit in extreme environments, such as in remote, prehospital settings or during aerospace medical transports, in which auscultation is impossible due to noise, or capnography is not available, and thus, requires further scientific evaluation.

Non-invasive ventilation for acute exacerbation of COPD with very high PaCO(2): A randomized controlled trial

Objective:

To assess the role of non-invasive positive pressure ventilation (NIPPV) for management of Indian patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Materials and Methods:

Forty patients (mean age 57.6 ± 10.8 years; M:F 31:9) with AECOPD with pH <7.35, admitted to the intensive care unit were included. Patients were randomized to receive NIPPV (N, n = 20) with conventional therapy or conventional therapy (C, n = 20) alone at admission. NIPPV was given through the nasal mask. Incidence of need of endotracheal intubation (ETI) was the primary efficacy variable. Hospital mortality, duration of hospital stay and change in clinical and blood gas parameters were the secondary outcome variables.

Results:

Mean pH at baseline for N and C groups were similar (7.23 ± 0.07) whereas PaCO₂ was 85.4 ± 14.8 and 81.1 ± 11.6 mm of Hg, respectively. At one hour, patients in N group had greater improvement in pH (P = 0.017) as well as PaCO₂ (P = 0.04) which corroborated with clinical improvement. Whereas need of ETI was reduced in patients who received NIPPV (3/20 vs 12/20, P = 0.003), in-hospital mortality was similar (3/20 and 2/20, P = NS). The mean duration of hospital stay was significantly shorter in N group (9.4 ± 4.3 days) as compared to C group (17.8 ± 2.6 days); P = 0.001.

Conclusions:

In patients with AECOPD, NIPPV leads to rapid improvement in blood gas parameters and reduces the need for ETI

Noninvasive positive pressure ventilation in unplanned extubation

BACKGROUND:

Unplanned extubation is quite common in intensive care unit (ICU) patients receiving mechanical ventilatory support. The present study aimed to investigate the effectiveness of noninvasive positive pressure ventilation (NPPV) in patients with unplanned extubation.

MATERIALS AND METHODS:

A total of 15 patients (12 male, age: 57 ± 24 years, APACHE II score: 19 ± 7) monitored at the medical ICU during the year 2004 who developed unplanned extubation were included in the study. NPPV was tried in all of them following unplanned extubation. Indications for admission to the ICU were as follows: nine patients with pneumonia, three with status epilepticus, one with gastrointestinal bleeding, one with cardiogenic pulmonary edema and one with diffuse alveolar bleeding.

RESULTS:

Eleven of the patients (74%) were at the weaning period at the time of unplanned extubation. Among these 11 patients, NPPV was successful in 10 (91%) and only one (9%) was reintubated due to the failure of NPPV. The remaining four patients (26%) had pneumonia and none of them were at the weaning period at the time of extubation, but their requirement for mechanical ventilation was gradually decreasing. Unfortunately, an NPPV attempt for 6–8 h failed and these patients were reintubated.

CONCLUSIONS:

Patients with unplanned extubation before the weaning criteria are met should be intubated immediately. On the other hand, when extubation develops during the weaning period, NPPV may be an alternative. The present study was conducted with a small number of patients, and larger studies on the effectiveness of NPPV in unplanned extubation are warranted for firm conclusions.

Complications of mechanical ventilation in the pediatric population

BACKGROUND

Mechanical ventilation (MV) strategies are continuously evolving in an effort to minimize adverse events. The objective of this study was to determine the complications associated with MV in children.

STUDY DESIGN

Prospective observational study. Over a period of 10 consecutive months, 150 patients (median age 0.8 years, IQR 4.4, 59% male) were enrolled in this study.

RESULTS

The median duration of MV was 3.1 days (IQR 3.9). A total of 85 complications were observed in 60 (40%) patients (114 complications per 1,000 ventilation days). 16.7% of patients developed atelectasis, 13.3% post-extubation stridor, 9.3% failed extubation, 2.0% pneumothorax, 3.3% accidental extubation, 2.7% nasal or perioral tissue damage and 1.9% ventilator associated pneumonia. Atelectasis occurred most often in the left lower lobe (36%) or in the right upper lobe (26%). The incidence of atelectasis in children <1 year of age was 12% (31 episodes per 1,000 days of ventilation) compared to 18% (57 episodes per 1,000 days of ventilation) in children ≥ 1 year of age (P < 0.05). Patients that failed extubation were ventilated for a median of 8.5 (IQR 8.8) days compared to 2.9 days (IQR, 3.8) in patients that were successfully extubated (P < 0.01). The absence of an air leak prior to extubation did not correlate with failed extubation. Accidental extubation was limited to orally intubated patients.

CONCLUSION

MV complications occurred in 40% of patients and most often consisted of atelectasis and post-extubation stridor. Further studies are needed to examine associated risk factors and strategies to reduce their occurrence.

An endotracheal intubation confirmation system based on carina image detection: a proof of concept

In this paper, a novel system for automatic confirmation of endotracheal intubation is proposed. The system comprises a miniature CMOS sensor and electric wires attached to a rigid stylet. Video signals are continuously acquired and processed by the algorithm implemented on a PC/DSP. The system is based on detection of the carina image as an anatomical landmark of correct tube positioning and it thus utilizes direct visual cues. Detection of the carina is performed based on unsupervised clustering, using a greedy-Gaussian mixture framework. The performance of the proposed system was initially evaluated using a mannequin model. A scientific prototype was assembled and used to perform repeated intubations on the model and collect a database of video signals which were processed off-line. The videos were categoried by a medical professional into carina, upper-trachea, and esophagus. An accuracy of 100% was achieved in discriminating between the carina and other anatomical structures including esophagus and upper-trachea. As an additional validation, the system was tested using a dataset of 231 video images recorded from five human subjects during intubation. The system correctly classified 120 out of 125 non-carina images (i.e. a sensitivity of 96.0%), and 100 out of 106 carina images (i.e. a specificity 94.3%). Using a 10th-order median filter, applied on the frame-based classification results, a 100% accuracy rate was obtained.

Endotracheal intubation confirmation based on video image classification using a parallel GMMs framework: a preliminary evaluation

In this paper, the problem of endotracheal intubation confirmation is addressed. Endotracheal intubation is a complex procedure which requires high skills and the use of secondary confirmation devices to ensure correct positioning of the tube. A novel confirmation approach, based on video images classification, is introduced. The approach is based on identification of specific anatomical landmarks, including esophagus, upper trachea and main bifurcation of the trachea into the two primary bronchi ("carina"), as indicators of correct or incorrect tube insertion and positioning. Classification of the images is performed using a parallel Gaussian mixture models (GMMs) framework, which is composed of several GMMs, schematically connected in parallel, where each GMM represents a different imaging angle. The performance of the proposed approach was evaluated using a dataset of cow-intubation videos and a dataset of human-intubation videos. Each one of the video images was manually (visually) classified by a medical expert into one of three categories: upper-tracheal intubation, correct (carina) intubation, and esophageal intubation. The image classification algorithm was applied off-line using a leave-one-case-out method. The results show that the system correctly classified 1517 out of 1600 (94.8%) of the cow-intubation images, and 340 out of the 358 human images (95.0%). The classification results compared favorably with a "standard" GMM approach utilizing textural based features, as well as with a state-of-the-art classification method, tested on the cow-intubation dataset.

Noninvasive ventilation: a survey of practice patterns of its use in India

Background and Aims:

To understand the practice patterns of noninvasive ventilation (NIV) use by Indian physicians.

Subjects and Methods:

Around three thousand physicians from all over India were mailed a questionnaire that could capture the practice patterns of NIV use.

Results:

Completed responses were received from 648 physicians (21.6%). Majority (n = 469, 72.4%, age 40 ± 9 years, M:F 409:60) use NIV in their clinical practice. NIV was most exclusively being used in the ICU setting (68.4%) and the commonest indication for its use was chronic obstructive pulmonary disease (COPD) (71.4%). A significant number did not report use of a conventional ventilator for NIV support (62%). Oronasal mask was the overwhelming favorite among the sampled physicians (68.2%). In most of the cases, the treating physician initiated NIV (60.8%) and a baseline blood gas analysis was performed in only 71.1% of the cases (315/443). Nasal bridge pressure sores was the commonest complication (64.2%).

Conclusions:

NIV is being widely used in clinical practice in India for various indications. COPD is the most common indication for its deployment. There seems to be a marked variability in the patterns relating to actual deployment of NIV, including the site of initiation, protocols for initiation followed, and monitoring of patients.

Beneficial effects of loxapine on agitation and breathing patterns during weaning from mechanical ventilation

INTRODUCTION

Interruption of sedation during weaning from mechanical ventilation often leads to patient agitation because of withdrawal syndrome. We tested the short-term efficacy and tolerance of loxapine in this situation.

METHODS

Nineteen mechanically ventilated patients with marked agitation after sedation withdrawal were included. Three agitation scales, the Richmond Agitation Sedation Scale (RASS), the Motor Activity Assessment Scale (MAAS), and the Ramsay and physiological variables (respiratory rate, airway occlusion pressure during the first 0.1 second of inspiration (P0.1), heart rate and systolic arterial blood pressure) were recorded before and after loxapine administration.

RESULTS

Loxapine dramatically improved all agitation scores (RASS and MASS decreased from 2 +/- 0 to -1.1 +/- 2.3, and 5.4 +/- 0.5 to 2.7 +/- 1.6, respectively; Ramsay increased from 1.0 +/- 0 to 3.5 +/- 1.5, 60 minutes after loxapine administration, P < 0.05 for all scores) as well as P0.1 (6 +/- 4.2 to 1.8 +/- 1.8 cm H2O; P < 0.05) and respiratory rate (from 31.2 +/- 7.2 to 23.4 +/- 7.8; P < 0.05) without hemodynamic adverse events. No side effects occurred. Sixteen (84%) patients were successfully managed with loxapine, sedation was resumed in two others, and one patient self-extubated without having to be reintubated.

CONCLUSIONS

Loxapine was safe and effective in treating agitation in a small group of mechanically ventilated patients and improved respiratory physiologic parameters, enabling the weaning process to be pursued. A multicenter trial is under way to confirm these promising results.

Diagnostic accuracy of the rapid shallow breathing index to predict a successful spontaneous breathing trial outcome in mechanically ventilated patients with chronic obstructive pulmonary disease

OBJECTIVE

To evaluate the diagnostic accuracy of 2 threshold values (105 breaths per minute [bpm]/L and 130 bpm/L) of the rapid shallow breathing index (RSBI) to predict a successful weaning trial outcome in a homogenous group of patients with chronic obstructive pulmonary disease (COPD).

METHODS

A consecutive population of patients with COPD who were intubated for hypercapnic respiratory failure during a 2-year period were studied prospectively. RSBI was measured by 2 investigators at minute 5 of the T-piece trial, whereas 2 other physicians evaluated the 30 minute T-piece trial as successful or unsuccessful, according to clinical criteria.

RESULTS

Of 64 patients with COPD (53 male, 11 female) who constituted the study population, 42 patients (35 male, 7 female; aged 70 ± 9.2 years) completed the spontaneous breathing trial (SBT) and remained clinically stable (group 1). The remaining 22 patients (18 male, 4 female; aged 71.9 ± 4.7 years) had to return to ventilatory support by the end of the SBT because of clinical deterioration (group 2). The 2 threshold values that were evaluated had low specificity (38.1% for < 105 bpm/L and 66.7% for < 130 bpm/L), low sensitivity (63.6% for < 105 bpm/L and 54.5% for < 130 bpm/L), and low diagnostic accuracy (46.8% for < 105 bpm/L and 65.6% for < 130 bpm/L) in predicting a successful T-piece trial outcome.

CONCLUSION

RSBI measured early during an SBT cannot accurately predict the successful outcome of a T-piece trial in a homogenous population of patients with COPD.

Pigtail catheter for the management of pneumothorax in mechanically ventilated patients

PURPOSE

There has been a paucity of data regarding the efficacy and safety of small-bore chest tubes (pigtail catheter) for the management of pneumothorax in mechanically ventilated patients.

METHODS

We conducted a retrospective review of mechanically ventilated patients who underwent pigtail catheter drainage as their initial therapy for pneumothorax in the emergency department and intensive care unit from January 2004 through January 2007 in a university hospital.

RESULTS

Among the 62 enrolled patients, there were 41 men (66%) and 21 women (34%), with a mean age of 63.8 +/- 20.3 years. A total of 70 episodes of pneumothoraces occurred in the intensive care unit, and 48 episodes of pneumothoraces (68.6%) were successfully treated with pigtail catheters. The average duration of pigtail drainage was 5.9 days (1-27 days). No major complications occurred through use of this procedure, except for pleural infections (n = 3, 4.2%) and clogged tube (n = 1, 1.4%). Comparing the variables between the success and failure of pigtail treatment, the failure group had a significantly higher proportion of Fio(2) >60% requirement (45.5% vs. 14.6%, P = .005) and higher positive end-expiratory pressure levels (8.7 +/- 3.0 vs. 6.2+/- 2.3 mm Hg, P = .001) at the time of pneumothorax onset than the success group. Further comparing the efficacy of pigtail drainage between barotraumas and iatrogenic pneumothorax, pigtail catheters for management of iatrogenic pneumothorax had a significantly higher success rate than barotraumas (87.5% vs. 43.3%, P < .0001).

CONCLUSION

Pigtail catheter drainage is relatively effective in treating iatrogenic but less promising for barotraumatic pneumothoraces.

Noninvasive Ventilation in Immunosuppressed Patients

In immunosuppressed patients (ISP) with acute respiratory failure (ARF), invasive mechanical ventilation (IMV) is associated with high mortality rate. Noninvasive ventilation (NIV) is a type of mechanical ventilation that does not require an artificial airway. It has seen increasing use in critically ill patients to avoid endotracheal intubation. Acute respiratory failure due to pulmonary infections is an important cause of illness in ISP and their treatment. Immunosuppressive treatments have showed an increase not only in the survival but also in the susceptibility to infection. Several authors have underlined the worst prognosis for neutropenic patients with ARF requiring endotracheal intubation and IMV. The NIV seems to be an interesting alternative in ISP because of the lower risk of complications; it prevents endotracheal intubation and its associated complications with survival benefits in this population.

Is there a best way to set tidal volume for mechanical ventilatory support?

Tidal breaths are an important component of mechanical ventilation. However, an inappropriate tidal volume setting can overstretch and injure the lung. Maximal stretch, tidal stretch, frequency of stretch, and rate of stretch are all implicated in such injury. Clinical trials have shown that limiting maximal and tidal stretch improves outcomes, even if gas exchange is partially compromised. Thus, current strategies should focus on limiting tidal and maximal stretch as much as possible.

Intramural haematoma of the oesophagus presenting as an unusual complication of endotracheal intubation

Intramural haematoma of the oesophagus is an uncommon and under-recognized condition. It may mimic other causes of chest pain, haematemesis, or dysphagia, and hence pose a diagnostic challenge. We report a case of an unusual presentation of intramural haematoma of the oesophagus occurring as a presumed complication of endotracheal intubation. It was disguised as acute onset post-operative chest pain, and resolved with conservative management. Awareness of this uncommon complication is important to allow rapid and timely diagnosis and management. We review the literature, causes and imaging features of this condition.

Impact of kinetic beds on the incidence of atelectasis in mechanically ventilated patients

We investigated the impact of kinetic beds on the incidence of atelectasis in mechanically ventilated patients in an intensive care unit (ICU). All bronchoscopies performed for atelectasis on mechanically ventilated patients between July 2000 and June 2001 and between July 2002 and June 2003 were reviewed. On July 26, 2001, 50 kinetic beds, 20 continuous lateral rotation therapy modules, and 20 percussion and vibration modules were introduced to our institution. Of the 3399 ICU admissions between July 2000 and June 2001, 71 patients developed atelectasis while being mechanically ventilated. Of the 3065 ICU admissions between July 2002 and June 2003, 83 patients developed atelectasis while being mechanically ventilated. Of these, 48 (58%) patients had left-sided atelectasis, 30 (36%) had right-sided atelectasis, and 5 (6%) had bilateral atelectasis. There was no decrease in the incidence of atelectasis in mechanically ventilated patients at our institution after the introduction of kinetic beds and vibration, percussion, and rotation modules despite their widespread availability.

Association of nursing workload and unplanned extubations in a pediatric intensive care unit

OBJECTIVE

To estimate nursing workload from the patient acuity level (PAL) assigned to patients in a pediatric intensive care unit (PICU) and to determine its influence on unplanned extubations.

DESIGN

Prospective cohort study.

SETTING

The 19-bed PICU of an urban, university-affiliated, tertiary children's hospital.

PATIENTS

All patients admitted to the PICU.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The study encompassed 2,193 nursing shifts and 1,919 admissions to the PICU over 24 months. The shift census averaged 12.0 patients (range 5-18) and was staffed by 9.4 nurses (range 4-16) for an average patient/nurse ratio of 1.3 +/- 0.2. Patients were assigned a PAL of 1-7 based on a classification system derived from time studies of 12 general nursing tasks. The total PALs per shift divided by the number of nursing staff yielded an average assignment of 5.8 +/- 0.7 PALs. Forty unplanned extubations (0.76 unplanned extubations/100 ventilator days) were observed during the study period. Logistic regression revealed positive associations between unplanned extubations and patient/nurse ratio (p = .03) and the shift PAL/nurse ratio (p = .01). The likelihood of an unplanned extubation when nurses covered >6.3 PALs was 3.8 times higher than during those shifts when they covered <5.3 PALs.

CONCLUSIONS

The likelihood of an unplanned extubation increased with higher patient/nurse and patient acuity/nurse ratios. Successful interventions to reduce the frequency of this medical error may need to address both nurse demand methodology and workload.