Use of diaphragm thickening fraction combined with rapid shallow breathing index for predicting success of weaning from mechanical ventilator in medical patients

Abstract Background Weaning failure is a crucial hindrance in critically ill patients. Rapid shallow breathing index (RSBI), a well-known weaning index, has some limitations in predicting weaning outcomes. A new weaning index using point-of-care ultrasound with diaphragmic thickening fraction (DTF) has potential benefits for improving weaning success. The aim of this study was to evaluate the efficacy of a combination of DTF and RSBI for predicting successful weaning compared to RSBI alone. Methods This prospective study enrolled patients from the medical intensive care unit or ward who were using mechanical ventilation and readied for weaning. Patients underwent a spontaneous breathing trial (SBT) for 1 h, and then, both hemi-diaphragms were visualized in the zone of apposition using a 10-MHz linear probe. Diaphragm thickness was recorded at the end of inspiration and expiration which supposed the lung volume equal to total lung capacity (TLC) and residual volume (RV), respectively, and the DTF was calculated as a percentage from this formula: thickness at TLC minus thickness at RV divided by thickness at RV. In addition, RSBI was calculated at 1 min after SBT. Weaning failure was defined as the inability to maintain spontaneous breathing within 48 h. Results Of the 34 patients enrolled, the mean (± SD) age was 66.5 (± 13.5) years. There were 25 patients with weaning success, 9 patients in the weaning failure group. The receiver operating characteristic curves of right and left DTF and the RSBI for the prediction of successful weaning were 0.951, 0.700, and 0.709, respectively. The most accurate cutoff value for prediction of successful weaning was right DTF ≥ 26% (sensitivity of 96%, specificity of 68%, positive predictive value of 89%, negative predictive value of 86%). The combination of right DTF ≥ 26% and RSBI ≤ 105 increased specificity to 78% but slightly decreased sensitivity to 92%. Intra-observer correlation increased sharply to almost 0.9 in the first ten patients and slightly increased after that. Conclusions Point-of-care ultrasound to assess diaphragm function has an excellent learning curve and helps physicians determine weaning readiness in critically ill patients. The combination of right DTF and RSBI greatly improved the accuracy for prediction of successful weaning compared to RSBI alone. Trial registration Thai Clinical Trials Registry, TCTR20171025001. Retrospectively registered on October 23, 2017

Incidence of chronic thromboembolic pulmonary hypertension in Thammasat University Hospital

Background: Chronic thromboembolic pulmonary hypertension (CTEPH) is usually underrecognized due to nonspecific presentations. Undiagnosed CTEPH leads to unnecessary investigations for other diseases, and more importantly, increased morbidities and mortality. Objectives: The aim of this study was to define overall CTEPH incidence and the rate of CTEPH after acute pulmonary embolism (APE) in a tertiary care university hospital and to record risk factors, clinical and imaging characteristics, diagnosis assessment, and management methods. Materials and Methods: The retrospective 5-year data, between 2012 and 2016, was extracted. Out of 1751 patients, we screened, 286 had, at least, evidence of pulmonary embolism. CTEPH was diagnosed in 20 patients, and 12 in this group had characteristics of combined APE or history of APE. Results: The overall incidence of CTEPH was 37.8 cases per million patients, and the incidence of CTEPH after APE was 5.1%. The most common presentation was progressive exertional dyspnea (50%). All patients were diagnosed by computed tomography pulmonary angiography combined with echocardiogram. Surprisingly, only two patients had investigations with ventilation/perfusion lung scan. None underwent the preferred curative surgical treatment of pulmonary endarterectomy and two had balloon pulmonary angioplasty. All patients received anticoagulants, while only 5 patients were treated with pulmonary arterial hypertension-specific drugs. Conclusion: CTEPH was uncommon in our institute, with an underuse of the standard test. Suboptimal diagnosis assessment and management remain critical problems. Developing a properly trained CTEPH care team would improve patient outcomes, but cost/resources may be prohibitive for such a relatively rare disease. Trial Registration: TCTR20180220008 registered February 19, 2018

Patient characteristics and outcomes of a home mechanical ventilation program in a developing country

Background: There are limited data on home mechanical ventilation (HMV) in developing countries. This study aimed to describe the patient characteristics, feasibility, and outcomes of an HMV program at a university hospital in Thailand. Materials and Methods: Data were collected on all patients who were discharged with HMV between October 2014 and August 2015 at Thammasat University Hospital. Results: Twelve patients (eight men and four women) underwent HMV. They were aged 71.5 ± 17.6 years; mean ± standard deviation. Indications for HMV were 6 neurologic diseases (4 amyotrophic lateral sclerosis, 1 multiple system atrophy, and 1 stroke), 2 chronic obstructive pulmonary disease (COPD), 1 tracheomalacia, and 3 combined neurologic diseases and respiratory diseases (2 stroke and COPD, 1 stroke and tracheomalacia). The duration of follow-up was 799.5 ± 780.5 days. The ratio of family income to cost of HMV usage was 77.2:1 ± 5.5:1. All patients had tracheostomies. Modes of HMV were biphasic positive airway pressure (66.7%), pressure-controlled ventilation (16.7%), pressure-support ventilation (8.3%), and volume-controlled ventilation (8.3%). Complications occurred in ten patients (83.3%), including tracheobronchitis (20 events) and ventilator-associated pneumonia (12 events). Overall mortality was 41.7% (5/12 patients), including two patients who died due to ventilator-associated pneumonia. There were no instances of ventilator malfunction. Conclusions: HMV is feasible for patients with neurological diseases and COPD in a developing country. The relatively high rate of complications indicates the need for more comprehensive clinical services for chronic ventilator-dependent patients in this setting

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

Background Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0–4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2–6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

Background: Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods: WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings: Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0-4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2-6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation: In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates. Funding: European Society of Intensive Care Medicine, European Respiratory Society