Measurement of a baseline minute ventilation for the calculation of minute ventilation recovery time: is a subjective method reliable?
BACKGROUND
Minute ventilation recovery time is a new predictor of extubation outcome that uses a subjective method for the determination of baseline minute ventilation (V(E)) during its measurement. The purpose of the current study is to evaluate the inter-rater reliability of this subjective method for determining baseline V(E).


METHODS
Three critical-care physicians served as independent readers. Each was trained with 5 practice V(E) trends, using the published method for determining baseline V(E), defined as the lowest, stable nadir lasting 15-30 min prior to the final weaning trial before extubation. Readers then determined baseline V(E) prospectively from an 8-hour V(E) trend for 19 patients who were weaning from mechanical ventilation in the surgical intensive care unit of a tertiary care hospital. Each V(E) trend was an objective recording of V(E) every 15 min for 8 hours, immediately prior to the final weaning trial before extubation.


RESULTS
There was excellent inter-rater reliability between trained readers for determination of a subjective V(E) baseline. Baseline V(E) was within 1 L/min for 15/19 patients (79%). Intra-class correlation across the 3 readers was 0.92 (p < 0.01). Tukey's test revealed no significant variability between readers (p > 0.5), and Spearman correlations between all reader pairs were significant (p < 0.01).


CONCLUSIONS
After minimal training, readers can reliably determine a subjective baseline V(E). This study validates the original methodology for determining baseline V(E), an essential step in the measurement of minute ventilation recovery time.
Seymour
Christopher W
CW
Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA 19104-4283, USA.
Christie
Jason D
JD
Gaughan
Christina
C
Fuchs
Barry D
BD
D000368:Aged; D020878:Device Removal / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D011446:Prospective Studies; D012123:Pulmonary Ventilation; D020127:Recovery of Function; D012016:Reference Values; D015300:Ventilator Weaning / Q000379:methods* / Q000592:standards*