Holets, Steven R

BACKGROUND: Current mechanical ventilation practice and the use of treatment adjuncts in patients requiring extracorporeal membrane oxygenation (ECMO) for refractory hypoxemia (RH) vary widely and their impact on outcomes remains unclear. In 2015, we implemented a standardized approach to protocolized ventilator settings and guide the escalation of adjunct therapies in patients with RH. This study aimed to investigate ICU mortality, its associated risk factors, and mechanical ventilation practice before and after the implementation of a standardized RH guideline in patients requiring venovenous ECMO (VV-ECMO). METHODS: This was a single-center, retrospective cohort study of patients undergoing VV-ECMO due to RH respiratory failure between January 2008 and March 2015 (before RH protocol implementation) and between April 2015 and October 2019 (after RH protocol implementation). RESULTS: A total of 103 subjects receiving VV-ECMO for RH were analyzed. After implementation of the RH protocol, more subjects received prone positioning (6.7% vs 23.3%, P = .02), and fewer received high-frequency oscillatory ventilation than before launching the RH protocol (0% vs 13.3%, P = .01). Plateau pressure was also lower before initiation of ECMO ( P = .04) and at day 1 during ECMO ( P = .045). Driving pressure was consistently lower at days 1, 2, and 3 after ECMO initiation: median 13.0 (interquartile range [IQR] 10.6–18.0) vs 16.0 (IQR 14.0–20.0) cm H 2 O at day 1 ( P = .003); 13.0 (IQR 11.0–15.9) vs 15.5 (IQR 12.0–20.0) cm H 2 O at day 2 ( P = .03); and 12.0 (IQR 10.0–14.5) vs 15.0 (IQR 12.0–19.0) cm H 2 O at day 3 ( P = .005). CONCLUSIONS: The implementation of a standardized RH guideline improved compliance with a lung-protective ventilation strategy and utilization of the prone position and was associated with lower driving pressure during the first 3 days after ECMO initiation in subjects with refractory hypoxemia.

Abstract Background: Patient-ventilator asynchrony (PVA) is commonly encountered during mechanical ventilation of critically ill patients. Estimates of PVA incidence vary widely. Type, risk factors, and consequences of PVA remain unclear. We aimed to measure the incidence and identify types of PVA, characterize risk factors for development, and explore the relationship between PVA and outcome among critically ill, mechanically ventilated adult patients admitted to medical, surgical, and medical-surgical intensive care units in a large academic institution staffed with varying provider training background.Methods: A single center, retrospective cohort study of all adult critically ill patients undergoing invasive mechanical ventilation for ≥12 hours.Results: A total of 676 patients who underwent 696 episodes of mechanical ventilation were included. Overall PVA occurred in 170 (24%) episodes. Double triggering 92(13%) was most common, followed by flow starvation 73(10%). A history of smoking, and pneumonia, sepsis, or ARDS were risk factors for overall PVA and double triggering (all P<0.05). Compared with volume targeted ventilation, pressure targeted ventilation decreased the occurrence of events (all P<0.01). During volume controlled synchronized intermittent mandatory ventilation and pressure targeted ventilation, ventilator settings were associated with the incidence of overall PVA. The number of overall PVA, as well as double triggering and flow starvation specifically, were associated with worse outcomes and fewer hospital-free days (all P<0.01).Conclusion: Double triggering and flow starvation are the most common PVA among critically ill, mechanically ventilated patients. Overall incidence as well as double triggering and flow starvation PVA specifically, portend worse outcome.

BACKGROUND: Liberal oxygenation during mechanical ventilation is harmful in critically ill patients and in certain subsets of patients, including those with stroke, acute myocardial infarction, and cardiac arrest. Surveillance through electronic medical records improves safety of mechanical ventilation in the ICU. To date, this practice has not been used for oxygen titration ( F IO 2 ) in adults. We hypothesize that a surveillance system based on the electronic medical record to alert respiratory therapists to titrate F IO 2 is feasible, safe, and efficacious. METHODS: In this pilot study, mechanically ventilated subjects were randomized to respiratory therapist-driven F IO 2 titration after an electronic alert versus standard of care (ie, titration based on physician order). An automated surveillance system utilizing a hyperoxemia-detection algorithm generated an electronic alert to a respiratory therapist’s pager. Hyperoxemia was defined as F IO 2 > 0.5 and S pO 2 > 95% for > 30 min. No other aspects of treatment were changed. We assessed feasibility, safety, and preliminary efficacy. Primary outcome was duration of hyperoxemia during mechanical ventilation. An unsafe outcome was identified as hypoxemia ( S pO 2 < 88%) within 1 h after titration per alert. Feasibility was assessed by a survey of respiratory therapists. RESULTS: Of 226 randomized subjects, 31 were excluded (eg, programming errors of the electronic alerts, no consent, physician discretion). We included 195 subjects, of whom 86 were in the intervention arm. Alert accuracy was 78%, and respiratory therapists responded to 64% of the alerts. During mechanical ventilation, exposure to hyperoxemia significantly decreased in the intervention group (median 13.5 h [interquartile range 6.2–29.4] vs 18.8 h [interquartile range 9.6–37.4]). No episodes of significant hypoxemia were registered. Most respiratory therapists agreed that the alert was helpful in reducing excessive oxygen exposure. CONCLUSIONS: Use of an electronic surveillance system to titrate F IO 2 was safe and feasible and showed preliminary efficacy in reducing hyperoxemia. Our study serves to justify larger randomized controlled trials for F IO 2 titration.

BACKGROUND: ARDS remains a source of significant morbidity and mortality in the critically ill patient. The mainstay of therapy entails invasive mechanical ventilation utilizing a lung-protective strategy designed to limit lung injury associated with excessive stress and strain while the underlying etiology of respiratory failure is identified and treated. Less is understood about what to do once conventional ventilation parameters have been optimized but the patient's respiratory status remains unchanged or worsens. In 2015, a protocolized, stepwise approach to mechanical ventilation with partially automated and clearly defined thresholds for management changes was implemented at our institution. We hypothesized that, by identifying appropriate patients earlier, time-to-escalation and rescue therapy implementation would be shortened. METHODS: Subjects with severe ARDS, treated with prone positioning based on our institution's protocolized approach from December 2013 to August 2016 were included. Their baseline characteristics, severity of illness scores, and mechanical ventilation parameters were collected and analyzed. RESULTS: Baseline characteristics, tidal volumes, P aO 2 / F IO 2 , duration of ventilation after proning, and mortality were similar in both groups. Median (interquartile range [IQR]) PEEP at the time of proning was higher after the protocol implementation (12.5 cm H 2 O [IQR 6.5–19.4] vs 18 cm H 2 O [IQR 10–22], P = .386), and mean (IQR) respiratory system driving pressure was lower (16 cm H 2 O [IQR 13–36.2] vs 12 cm H 2 O [IQR 9–19.6], P = .029). Median (IQR) time from refractory hypoxemia identification to proning was shorter after protocol implementation (42.2 h [IQR 6.83–347.2] vs 16.3 h [IQR 1–99.7], I = .02), and P aO 2 / F IO 2 at 1 h after proning was higher. ICU and hospital LOS were shorter after the protocol implementation. CONCLUSIONS: Following the implementation of an early, evidence-based, protocolized approach to optimizing mechanical ventilation, subjects with true refractory hypoxemia were identified earlier and time to proning was significantly shorter. Despite improvement in the evaluation and management of refractory hypoxemia as well as time to initiation of prone positioning, mortality was unchanged and there was variation in the duration of the position.