Empirical Probability of Positive Response to PEEP Changes and Mechanical Ventilation Factors Associated With Improved Oxygenation During Pediatric Ventilation

• Published in: Respiratory care Vol. 64; no. 10; pp. 1193 - 1198
• Main Authors: Smallwood, Craig D, Walsh, Brian K, Arnold, John H, Gouldstone, Andrew
• Format: Journal Article
• Language: English
• Published: United States Daedalus Enterprises, Inc 01.10.2019
• Subjects: Analysis; Medical research; Pediatrics; Probability theory; United Kingdom; Massachusetts; oxygenation; mechanical ventilation; dead-space ventilation; positive end-respiratory pressure; pediatrics
• ISSN: 0020-1324; 1943-3654
• DOI: 10.4187/respcare.06707

PEEP is titrated to improve oxygenation during mechanical ventilation. It is clinically desirable to identify factors that are associated with a clinical improvement or deterioration following a PEEP change. However, these factors have not been adequately described in the literature. Therefore, we aimed to quantify the empirical probability of PEEP changes having a positive effect upon oxygenation, compliance of the respiratory system (C ), and the ratio of dead space to tidal volume (V /V ). Further, clinical factors associated with positive response during pediatric mechanical ventilation are described. Mechanically ventilated pediatric subjects in the ICU were eligible for inclusion in the study. During PEEP increases (PEEP ), a responder was defined as having an improved S /F ratio; non-responders demonstrated a worsening S /F ratio in the following hour. When PEEP was decreased (PEEP ), a responder was anyone who maintained or increased the S /F ratio; non-responders demonstrated a worsening S /F ratio. Features from continuous mechanical ventilation variables were extracted, and differences between responders and non-responders were identified. 286 PEEP change cases were eligible for analysis in 76 subjects. For PEEP cases, the empirical probability of positive response was 56%, 67%, and 54% for oxygenation, C , and V /V , respectively. The median S /F increase was 13. For PEEP , the empirical probability of response was 46%, 53%, and 46% for oxygenation, C , and V /V , respectively. PEEP responders had higher F requirements (70.8 vs 52.5%, < .001), mean airway pressure (14.0 vs 12.9 cm H O, = .03), and oxygen saturation index (9.9 vs 7.5, = .002) versus non-responders. For PEEP , V /V was lower in responders (0.46 vs 0.50, = .031). In children requiring mechanical ventilation, the responder rate was modest for both PEEP and PEEP cases. These data suggest that PEEP titration often does not have the desired clinical effect, and predicting which patients will manifest a positive response is complex, requiring more sophisticated means of assessing individual subjects.