Esophageal Pressure Measurement: A Primer.

Over the last decade, the literature exploring clinical applications for esophageal manometry in critically ill patients has increased. New mechanical ventilators and bedside monitors allow measurement of esophageal pressures easily at the bedside. The bedside clinician can now evaluate the magnitude and timing of esophageal pressure swings to evaluate respiratory muscle activity and transpulmonary pressures. The respiratory therapist has all the tools to perform these measurements to optimize mechanical ventilation delivery. However, as with any measurement, technique, fidelity, and accuracy are paramount. This primer highlights key knowledge necessary to perform measurements and highlights areas of both uncertainty and ongoing development.

Endotracheal Tube Obstruction Among Patients Mechanically Ventilated for ARDS Due to COVID-19: A Case Series.

BACKGROUND: Patients with COVID-19 and ARDS on prolonged mechanical ventilation are at risk for developing endotracheal tube (ETT) obstruction that has not been previously described in patients with ARDS due to other causes. The purpose of this report is to describe a case series of patients with COVID-19 and ARDS in which ETT occlusion resulted in significant clinical consequences and to define the pathology of the obstructing material. METHODS: Incidents of ETT occlusion during mechanical ventilation of COVID-19 patients were reported by clinicians and retrospective chart review was conducted. Statistical analysis was performed comparing event rates between COVID-19 and non-COVID 19 patients on mechanical ventilation over the predefined period. Specimens were collected and submitted for pathological examination. FINDINGS: Eleven COVID-19 patients experienced endotracheal tube occlusion over a period of 2 months. Average age was 69 (14.3, range 33-85) years. Mean APACHE III score was 73.6 (17.3). All patients had AKI and cytokine storm. Nine exhibited biomarkers for hypercoagulability. Average days on mechanical ventilation before intervention for ETT occlusion was 14 (5.18) days (range of 9 to 23 days). Five patients were discharged from the ICU, and 4 expired. Average documented airway resistance on admission was 14.2 (3.0) cm H2O/L/sec. Airway resistance before tube exchange was 28.1 (8.0) cm H2O /L/sec. No similar events of endotracheal tube occlusion were identified in non-COVID patients on mechanical ventilation during the same time period. Microscopically, the material consisted of mucin admixed with necrotic cell debris, variable numbers of degenerated inflammatory cells, oral contaminants and red blood cells. INTERPRETATION: Patients with COVID-19 and ARDS on prolonged mechanical ventilation are at risk for developing ETT obstruction due to deposition of a thick, tenacious material within the tube that consists primarily of mucin and cellular debris. Clinicians should be aware of this dangerous but treatable complication.

Noninvasive positive pressure ventilation in stable patients with COPD.

PURPOSE OF REVIEW: Long-term noninvasive positive pressure ventilation (NIV) used to be a controversial form of therapy for patients with stable hypercapnic chronic obstructive pulmonary disease (SH-COPD). New evidence described in this review defines the optimal settings, timing and target population for NIV utilization in SH-COPD necessary to maximize its benefit. RECENT FINDINGS: NIV, when titrated appropriately, leads to improved clinical outcomes. High inspiratory positive airway pressures aimed at decreasing CO2 levels can ensure NIV success in SH-COPD. NIV initiated when patients remain hypercapnic whereas in a clinical stable state following an acute exacerbation can prolong the time to a readmission. Technological advances in NIV algorithms and remote monitoring have the potential to improve use and titration. NIV and portable NIV improve exercise tolerance and may accentuate the benefits derived from pulmonary rehabilitation alone. SUMMARY: Use of high-intensity NIV in SH-COPD is beneficial yet appropriate patient selection and implementation is paramount.

Non-invasive positive pressure ventilation in lung transplant recipients with acute respiratory failure: Beyond the perioperative period.

PURPOSE: The purpose of this study is to evaluate outcomes in MICU lung transplant recipients with acute respiratory failure treated with non-invasive positive pressure ventilation (NPPV) and identify factors associated with NPPV failure (need for intubation). METHODS: Retrospective chart review of all lung transplant recipients who were admitted with acute respiratory failure to the MICU from January 2009-August 2016 was completed. Logistic regression analysis was performed to determine which factors were independently associated with NPPV failure. RESULTS: Of 156 patients included in the study, 125 (80.1%) were tried on NPPV. Sixty-eight (54.4%) were managed successfully with NPPV with a hospital survival rate of 94.1%. Subjects who failed NPPV had higher hospital mortality, similar to those intubated from the outset (15 [48.3%]; 22 [38.6%], p = .37). In multivariate analyses, APACHE III scores >78 (9.717 [3.346, 28.22]) and PaO2/FiO2 ≤ 151 (4.54 [1.72, 11.99]) were associated with greater likelihood of NPPV failure. There was no difference in NPPV failure based on the presence of BOS. In patients with high severity of illness, there was no difference in mortality between initial IMV and NPPV failure when stratified on the basis of hypoxemia (PaO2/FiO2 > 151, p-value 0.34; PaO2/FiO2 ≤ 151, p-value 0.99). CONCLUSIONS: NPPV is a viable option for lung transplant recipients with acute respiratory failure. Extreme caution should be exercised when used in patients with high severity of illness (APACHE III >78) and/or severe hypoxemia (PaO2/FiO2 ≤ 151).

Interhospital transfers of the critically ill: Time spent at referring institutions influences survival.

OBJECTIVE: To determine if the length of stay at a referring institution intensive care unit (ICU) before transfer to a tertiary/quaternary care facility is a risk factor for mortality. DESIGN: We performed a retrospective chart review of patients transferred to our ICU from referring institution ICUs over a 3-year period. Logistical regression analysis was performed to determine which factors were independently associated with increased mortality. The primary outcomes were ICU and hospital mortality. MAIN RESULTS: A total of 1248 patients were included in our study. Length of stay at the referring institution was an independent risk factor for both ICU and hospital mortality (P<.0001), with increasing lengths of stay correlating with increased mortality. Each additional day at the referring institution was associated with a 1.04 increase in likelihood of ICU mortality (95% confidence interval, 1.02-1.06; P =0.001) and a 1.029 (95% confidence interval, 1.01-1.05; P .005) increase in likelihood of hospital mortality. CONCLUSIONS: Length of stay at the referring institution before transfer is a risk factor for worse outcomes, with longer stays associated with increased likelihood of mortality. Further studies delineating which factors most affect length of stay at referring institutions, though a difficult task, should be pursued.