Ventilation by mask before and after the administration of neuromuscular blockade: a pragmatic non-inferiority trial

Table 4 Comparison of selected outcomes of face mask ventilation before and after administration of neuromuscular blocking drugs. Data presented as mean (SD), median (IQR [range]), or number (%)

	Before	After	Mean difference (95 % CI)	p-value^a,b
Vt, ml.breath⁻¹	399 (169)	428 (166)	30 (12, 47)	0.001
PIP, cmH₂O	19 (5.5)	17 (3.4)	−1.7 (−1, −2.4)	<0.001
Breaths delivered	14 (2.2)	15 (1.5)	---	<0.001
V_E, l.min⁻¹	5.6 (2.5)	6.3 (2.5)	0.6 (0.4, 0.9)	<0.001
Han scale	1 (1-2 [1–4])	1 (1-2 [1–4])	---	0.11
Warters scale	5 (0-6 [0–10])	2 (0-5 [0–9])	−0.7 (−0.4, −1)	<0.001
MV_i or V_ds	35 (16.6)	27 (12.8)	---	0.20

Predicted body weight based on height in inches and gender from National Heart, Lung and Blood Institute Acute Respiratory Distress Syndrome Network formula, which can be accessed at http://www.ardsnet.org/files/pbwtables_2005-02-02.pdf
^aComparisons made by paired t-test or Wilcoxon signed rank test for normally and non-normally distributed paired continuous data, respectively. Mean difference displayed for normally distributed continuous data only.^bComparison made by McNemar’s test for paired proportions of binomial data
Vt tidal volume, PIP peak inspiratory pressure, CI confidence interval, SD standard deviation, V_E minute ventilation, MV_i inadequate mask ventilation (<4 ml.kg⁻¹ predicted body weight), V_ds dead-space ventilation (<150 ml, no clinical sign of ventilation)

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