Table 2.

Opioid exposure and mechanical ventilation

Study group	IWS-negative (n = 45) Median (25th–75th percentile) [min, max]	IWS-positive (n = 9) Median (25th–75th percentile) [min, max]	p value
Cumulative opioid dose prior to weaning (mcg/kg)	169.4 (117,7–234,2) [11.7, 865.6]	245.7 (135,7–437,6) [72.4, 722.4]	p = 0.32
Duration of opioid infusion until the first wean (h)a	125 (88–243) [57, 564]	151 (81–397) [76, 428]	p = 0.47
Duration of mechanical ventilation (h)b	188 (122–340) [59, 1201]	286 (207–566) [111, 1245]	p = 0.08
Weaning rate (%)	75 (50–100) [12.50, 100]	100 (40–100) [20, 100]	p = 0.98

Weaning rate is defined as the difference between the previous stable infusion rate and the new stable infusion rate

^aThe last observation carried forward method was used for 1 patient in each group; opioid begin date = ICU admission date

^bThe last observation carried forward was used for 3 patients in IWS-negative group and 1 in IWS-positive group