The recently diagnosed coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in December 2019 commonly affects the respiratory system. The ...incidence of acute hypoxic respiratory failure varied among epidemiological studies with high percentage of patients requiring mechanical ventilation with a high mortality. Noninvasive ventilation is an alternative tool for ventilatory support instead of invasive mechanical ventilation, especially with scarce resources and intensive care beds. Initially, there were concerns by the national societies regarding utilization of noninvasive ventilation in acute respiratory failure. Recent publications reflect the gained experience with the safe utilization of noninvasive mechanical ventilation. Noninvasive ventilation has beneficiary role in treatment of acute hypoxic respiratory failure with proper indications, setting, monitoring, and timely escalation of therapy. Patients should be monitored frequently for signs of improvement or deterioration in the clinical status. Awareness of indications, contraindications, and parameters reflecting either success or failure of noninvasive ventilation in the management of acute respiratory failure secondary to COVID-19 is essential for improvement of outcomes.
A 44-year-old man with a history of coronary artery disease, type 2 diabetes mellitus, and OSA reported progressively worsening dyspnea on exertion over a 6-week period. Outpatient CT angiogram ...revealed a pulmonary artery filling defect. He was sent to the ED where he was started on a heparin drip for unprovoked pulmonary embolism (PE). Echocardiogram revealed normal cardiac function without evidence of right heart strain. Lower extremity ultrasound was negative for DVT. He improved symptomatically, and no risk factors for PE were identified. He was discharged on apixaban. Five weeks later, the patient returned to the ED with hemoptysis. He reported compliance with anticoagulation and improvement of his dyspnea on exertion. History remained negative for recent travel, trauma, surgery, clotting disorders, thromboembolic disease, and alcohol or drug use. He had a 60 pack-year cigarette smoking history and quit 3 months prior.
Purpose
To systematically review and compare ultrasonographic methods and their utility in predicting non-invasive ventilation (NIV) outcomes.
Methods
A systematic review was performed using the ...PubMed, Medline, Embase, and Cochrane databases from January 2015 to March 2023. The search terms included the following: ultrasound, diaphragm, lung, prediction, non-invasive, ventilation, and outcomes. The inclusion criteria were prospective cohort studies on adult patients requiring non-invasive ventilation in the emergency department or inpatient setting.
Results
Fifteen studies were analyzed, which comprised of 1,307 patients (
n
= 942 for lung ultrasound score studies;
n
= 365 patients for diaphragm dysfunction studies). Lung ultrasound scores (LUS) greater than 18 were associated with NIV failure with a sensitivity 62–90.5% and specificity 60–91.9%. Similarly, a diaphragm thickening fraction (DTF) of less than 20% was also associated with NIV failure with a sensitivity 80–84.6% and specificity 76.3–91.5%.
Conclusion
Predicting NIV failure can be difficult by routine initial clinical impression and diagnostic work up. This systematic review emphasizes the importance of using lung and diaphragm ultrasound, in particular the lung ultrasound score and diaphragm thickening fraction respectively, to accurately predict NIV failure, including the need for ICU-level of care, requiring invasive mechanical ventilation, and resulting in higher rates of mortality.
Abstract
Background
Heart rate, acidosis, consciousness, oxygenation, and respiratory rate (HACOR) have been used to predict noninvasive ventilation (NIV) failure. However, the HACOR score fails to ...consider baseline data. Here, we aimed to update the HACOR score to take into account baseline data and test its predictive power for NIV failure primarily after 1–2 h of NIV.
Methods
A multicenter prospective observational study was performed in 18 hospitals in China and Turkey. Patients who received NIV because of hypoxemic respiratory failure were enrolled. In Chongqing, China, 1451 patients were enrolled in the training cohort. Outside of Chongqing, another 728 patients were enrolled in the external validation cohort.
Results
Before NIV, the presence of pneumonia, cardiogenic pulmonary edema, pulmonary ARDS, immunosuppression, or septic shock and the SOFA score were strongly associated with NIV failure. These six variables as baseline data were added to the original HACOR score. The AUCs for predicting NIV failure were 0.85 (95% CI 0.84–0.87) and 0.78 (0.75–0.81) tested with the updated HACOR score assessed after 1–2 h of NIV in the training and validation cohorts, respectively. A higher AUC was observed when it was tested with the updated HACOR score compared to the original HACOR score in the training cohort (0.85 vs. 0.80, 0.86 vs. 0.81, and 0.85 vs. 0.82 after 1–2, 12, and 24 h of NIV, respectively; all
p
values < 0.01). Similar results were found in the validation cohort (0.78 vs. 0.71, 0.79 vs. 0.74, and 0.81 vs. 0.76, respectively; all
p
values < 0.01). When 7, 10.5, and 14 points of the updated HACOR score were used as cutoff values, the probability of NIV failure was 25%, 50%, and 75%, respectively. Among patients with updated HACOR scores of ≤ 7, 7.5–10.5, 11–14, and > 14 after 1–2 h of NIV, the rate of NIV failure was 12.4%, 38.2%, 67.1%, and 83.7%, respectively.
Conclusions
The updated HACOR score has high predictive power for NIV failure in patients with hypoxemic respiratory failure. It can be used to help in decision-making when NIV is used.
A crucial step in the transition from mechanical ventilation to extubation is the successful performance of a spontaneous breathing trial (SBT). The American College of Chest Physicians (ACCP) ...Guidelines recommend removal of the endotracheal tube upon successful completion of a SBT. However, this does not guarantee successful extubation as there remains a risk of re-intubation. Guidelines have outlined ventilator liberation protocols, selected use of non-invasive ventilation on extubation, early mobilization, and dynamic ventilator metrics to prevent and better predict extubation failure. However, a significant percentage of patients still fail mechanical ventilation discontinuation. A common reason for re-intubation is having a weak cough strength, which reflects the inability to protect the airway. Evaluation of cough strength via objective measures using peak expiratory flow rate is a non-invasive and easily reproducible assessment which can predict extubation failure. We conducted a narrative review of the literature regarding use of cough strength as a predictive index for extubation failure risk. Results of our review show that cough strength, quantified objectively with a cough peak expiratory flow measurement (CPEF), is strongly associated with extubation success. Furthermore, various cutoff thresholds have been identified and can provide reasonable diagnostic accuracy and predictive power for extubation failure. These results demonstrate that measurement of the CPEF can be a useful tool to predict extubation failure in patients on MV who have passed a SBT. In addition, the data suggest that this diagnostic modality may reduce ICU length of stay, ICU expenditures, and morbidity and mortality.
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