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.

Mechanical power normalized to lung-thorax compliance indicates weaning readiness in prolonged ventilated patients

Since critical respiratory muscle workload is a significant determinant of weaning failure, applied mechanical power (MP) during artificial ventilation may serve for readiness testing before proceeding on a spontaneous breathing trial (SBT). Secondary analysis of a prospective, observational study in 130 prolonged ventilated, tracheotomized patients. Calculated MP’s predictive SBT outcome performance was determined using the area under receiver operating characteristic curve (AUROC), measures derived from k-fold cross-validation (likelihood ratios, Matthew's correlation coefficient [MCC]), and a multivariable binary logistic regression model. Thirty (23.1%) patients failed the SBT, with absolute MP presenting poor discriminatory ability (MCC 0.26; AUROC 0.68, 95%CI [0.59‒0.75], p = 0.002), considerably improved when normalized to lung-thorax compliance (LTCdyn-MP, MCC 0.37; AUROC 0.76, 95%CI [0.68‒0.83], p < 0.001) and mechanical ventilation PaCO2 (so-called power index of the respiratory system [PIrs]: MCC 0.42; AUROC 0.81 [0.73‒0.87], p < 0.001). In the logistic regression analysis, PIrs (OR 1.48 per 1000 cmH2O2/min, 95%CI [1.24‒1.76], p < 0.001) and its components LTCdyn-MP (1.25 per 1000 cmH2O2/min, [1.06‒1.46], p < 0.001) and mechanical ventilation PaCO2 (1.17 [1.06‒1.28], p < 0.001) were independently related to SBT failure. MP normalized to respiratory system compliance may help identify prolonged mechanically ventilated patients ready for spontaneous breathing.

Clinical Factors Associated With Failed Weaning From Intraoperative Extracorporeal Membrane Oxygenation Used During Lung Transplantation

Background: Extracorporeal membrane oxygenation (ECMO) promotes adequate oxygenation and hemodynamic stability during lung transplantation (LTx). However, some recipients cannot be weaned from ECMO following surgery. Thus, we evaluated the prognosis and risk factors of failed weaning from intraoperative ECMO during LTx.Methods: We retrospectively analyzed data from 274 patients receiving intraoperative ECMO during LTx. Risk factors were evaluated using logistic regression analyses.Results: Weaning failure occurred in 118 patients (43.1%). Intensive care unit stay was longer and mortality was higher in the failed weaning group than in the successful weaning group. The failed weaning group exhibited significantly older donor age, lower donor PaO2/FiO2 ratio, greater intraoperative transfusion volume, and longer operation time than the successful weaning group. Recipient age, body mass index, donor age, lower donor PaO2/FiO2 ratio, donor/recipient total lung capacity (TLC) ratio, greater intraoperative transfusion volume, and longer operation time were associated with weaning failure after adjustment. Conclusion: The failed weaning group showed a poor prognosis. Perioperative factors including donor age, donor PaO2/FiO2 ratio, donor/recipient TLC, operation time, and blood loss can predict postoperative ECMO weaning failure.

THE IDEAL PROFILE (INCREASE IN B-LINES/DELTA B-LINES) ON LUNG ULTRASOUND FOR DIAGNOSING WEANING INDUCED PULMONARY EDEMA IN VENTILATED PATIENTS

Objective: To ascertain the ideal number of B-lines on lung ultrasound for the diagnosis of weaning induced pulmonary edema in ventilated patients. Study Design: Prospective observational study. Place and Duration of Study: Department of Medicine, Shifa International Hospital, Islamabad, from Jan to Aug 2020. Methodology: All the patients over the age of 18 years who were on mechanical ventilation in a medical intensive care unit were included in the study. The patients were given spontaneous breathing trials as a protocol for weaning from mechanical ventilation. Lung ultrasound was performed on 4 points of anterior chest wall before and after spontaneous breathing trials. Before and after spontaneous breathing trials counting of B lines was done on ultrasound of lung and comparison of increase in B lines (Delta-B-lines) was done with reference diagnosis of weaning induced pulmonary edema diagnosed by intensivist who was blinded to the results of lung ultrasound. Results: The study included 42 patients including 23 (54.8%) men and 19 (45.2%) women. 14 cases failed spontaneous breathing trials. Seven cases (16.7%) had weaning induced pulmonary edema. Delta-B-lines ≥6 diagnosed weaning induced pulmonary edema with 100% accuracy. Out of the remaining seven patients with weaning failure but without weaning induced pulmonary edema, 6 (28.6%) had Delta-B-lines ≥6. The ultrasound lung technique had a 100% sensitivity profile to detect weaning induced pulmonary edema and a specificity of 77.78%. Conclusion: The study indicates that Delta-B-lines ≥6 diagnosed the weaning induced pulmonary edema with the best accuracy.

Diaphragm Ultrasound in the Evaluation of Diaphragmatic Dysfunction in Lung Disease

The diaphragm is the most important respiratory muscle, and its function may be limited by acute and chronic diseases. A diaphragmatic ultrasound, which quantifies dysfunction through different approaches, is useful in evaluating work of breathing and diaphragm atrophy, predicting successful weaning, and diagnosing critically ill patients. This technique has been used to determine reduced diaphragmatic function in patients with chronic obstructive pulmonary disease and interstitial diseases, while in those with COVID-19, diaphragmatic ultrasound has been used to predict weaning failure from mechanical ventilation.

Weaning Failure in Critically Ill Patients Is Related to the Persistence of Sepsis Inflammation

Introduction: Septic patients undergoing mechanical ventilation (MV) often experience difficulty in weaning. Th aim of this study was to determine whether inflammatory biomarkers of sepsis could be indicative of the failure or success of spontaneous breathing trial (SBT) in these patients. Methods: Sixty-five patients on MV (42 septic and 23 intubated for other reasons) fulfilling the criteria for SBT were included in the study. Blood samples were collected right before, at the end of (30 min) and 24 h after the SBT. Serum inflammatory mediators associated with sepsis (IL-18, IL-18BP, TNF) were determined and correlated with the outcome of SBT. Results: A successful SBT was achieved in 45 patients (69.2%). Septic patients had a higher percentage of SBT failure as compared to non-septic patients (85% vs. 15%, p = 0.026), with an odds ratio for failing 4.5 times (OR = 4.5 95%CI: 1.16–17.68, p 0.022). IL-18 levels and the relative mRNA expression in serum were significantly higher in septic as compared to non-septic patients (p < 0.05). Sepsis was independently associated with higher serum IL-18 and TNF levels in two time-point GEE models (53–723, p = 0.023 and 0.3–64, p = 0.048, respectively). IL-18BP displayed independent negative association with rapid shallow breathing index (RSBI) (95% CI: −17.6 to −4, p = 0.002). Conclusion: Sustained increased levels of IL-18 and IL-18BP, acknowledged markers of sepsis, were found to be indicative of SBT failure in patients recovering from sepsis. Our results show that, although subclinical, remaining septic inflammation that sustaines for a long time complicates the weaning procedure. Biomarkers for the estimation of the septic burden and the right time for weaning are needed.

Correlation between Handgrip Strength and Rapid Shallow Breathing Index for Assessment of Weaning from Mechanical Ventilation

Background. Assessment of weaning from mechanical ventilation (MV) is an important process. Rapid shallow breathing index (RSBI) is a standard tool to evaluate a patient’s readiness before the spontaneous breathing trial (SBT). Handgrip strength (HGS) is an alternative method for assessment of respiratory muscle strength. Relationship between HGS and RSBI has not been explored. This study aimed to determine the correlation between HGS and RSBI to predict successful extubation in mechanically ventilated patients. Methods. A prospective study was conducted in screened 120 patients requiring MV with tracheal intubation >48 h. HGS was performed at 48 h after intubation, 10 min before and 30 min after SBT, and 1 h after extubation. RSBI was performed at 10 min before SBT. Results. A total of 93 patients (58% men) were included in the final analysis. Mean age was 71.6 ± 15.2 years. Patients admitted in general medical wards were 84.9%. APACHE II score was 13.5 ± 4.7. Most patients were intubated from pneumonia (39.8%). Weaning failure was 6.5%. The main result shows that HGS was negatively correlated with RSBI (regression coefficient −0.571, P < 0.001 ). The equation for predicting RSBI, derived from the linear regression model, was predicted RSBI (breaths/min/L) = 39.285 + (age ∗ 0.138)–(HGS ∗ 0.571). Conclusions. HGS had significantly negative correlation with RSBI for assessment of weaning from MV. A prospective study of the HGS cutoff value is needed to investigate the difference between patients who succeeded and those who failed extubation. This trial is registered with TCTR20180323004.

Ultrasound-Guided Preload Indices during Different Weaning Protocols of Mechanically Ventilated Patients and its Impact on Weaning Induced Cardiac Dysfunction

BACKGROUND: Elevation of the left ventricular (LV) filling pressure can occur during weaning of mechanical ventilation due to increase in LV preload and/or changes in LV compliance and LV afterload. AIM: The aim of the study was to evaluate respiratory changes in internal jugular vein and inferior vena cava during weaning from mechanical ventilation. METHODS: Prospective observational study conducted on 80 consecutive patients. Patients were divided randomly into two groups who met the readiness criteria to start spontaneous breathing trial (SBT) either on pressure support ventilation (PS/CPAP) for 30 min or T-piece for 120 min. Weaning failure was defined as a failed SBT or reintubation within 48 h. Echocardiographic evaluation was done on assisted controlled ventilation and at the end of SBT for preload assessment. RESULTS: Mitral Septal E/E’ Cutoff value ≥6.1 with sensitivity 81% and specificity 84.2%, and AUC 0.73 for predicting weaning failure. IVC distensibility index on CPAP cutoff value ≥66.5% with sensitivity 100% and specificity 68.4%, and AUC 0.85. In Group II, Mitral Septal E/E’ Cut off value ≥5.8 with sensitivity 83% and specificity 90.9%, AUC 0.83, IVC collapsibility index Cut off value ≥45.5% with sensitivity 72% and specificity 86%, AUC 0.73. CONCLUSION: Mitral Septal E/E’ could predict weaning-induced diastolic dysfunction. IVC plays an important role in predicting weaning failure.

Ultrasound Assessment in Cardiogenic Shock Weaning: A Review of the State of the Art

Cardiogenic shock (CS) is associated with a high in-hospital mortality despite the achieved advances in diagnosis and management. Invasive mechanical ventilation and circulatory support constitute the highest step in cardiogenic shock therapy. Once established, taking the decision of weaning from such support is challenging. Intensive care unit (ICU) bedside echocardiography provides noninvasive, immediate, and low-cost monitoring of hemodynamic parameters such as cardiac output, filling pressure, structural disease, congestion status, and device functioning. Supplemented by an ultrasound of the lung and diaphragm, it is able to provide valuable information about signs suggesting a weaning failure. The aim of this article was to review the state of the art taking into account current evidence and knowledge on ICU bedside ultrasound for the evaluation of weaning from mechanical ventilation and circulatory support in cardiogenic shock.

Handgrip strength cutoff value predicting successful extubation in mechanically ventilated patients

Background Handgrip strength (HGS) is an alternative tool to evaluate respiratory muscle function. HGS cutoff value indicating extubation success or failure has not been investigated. This study aimed to determine HGS cutoff value to predict successful extubation. Methods A prospective study was conducted. Patients requiring intubated mechanical ventilation with intubation ≥ 48 hours in medical wards were recruited. HGS test was performed at 10 minutes before and 30 minutes after spontaneous breathing trial (SBT). Rapid shallow breathing index (RSBI) was measured at 10 minutes before SBT. Results Ninety-three patients (58% men) were included. Mean age was 71.6 ± 15.2 years. Weaning failure rate was 6.5%. The area under the ROC curve of 0.84 for the best HGS cutoff value at 10 minutes before SBT was 12.7 kg, with 75.9% sensitivity and 83.3% specificity (P = 0.005). The best HSG cutoff value at 30 minutes after SBT was 14.9 kg, with the area under the ROC curve of 0.82, with 58.6% sensitivity and 83.3% specificity (P = 0.009). The best RSBI cutoff value was 43.5 breaths/min/L, with the area under the ROC curve of 0.46, 33.3% sensitivity and 66.6% specificity (P = 0.737). Conclusions HGS may be a predictive tool to guide extubation with better sensitivity and specificity than RSBI. A prospective study is needed to verify HGS test as adjunctive to RSBI in ventilator weaning protocol.