Role of lung ultrasound in assessing positive end expiratory pressure induced lung recruitment in patients on mechanical ventilation

Table 1 Distribution of the study subjects based on indications for mechanical ventilation

Indications	Frequency (n)	Percentage (%)
Airway protection	13	35.1
Alveolar filling defect	4	10.8
Impaired central drive	4	10.8
Post anesthesia recovery	7	18.9
Pulmonary vascular defect	2	5.4
Respiratory muscle weakness	2	5.4
Restrictive ventilatory defect	5	13.5

Table 2 Distribution of the subjects based on the requirement of positive end expiratory pressure over the period of study

Positive end expiratory pressure		Frequency (n)	Percentage (%)
5 cm H2O (trial 1)	Yes	37	100.0
	No	0	0.0
10 cm H2O (trial 2)	Yes	20	54.1
	No	17	45.9
15 cm H2O (trial 3)	Yes	5	13.5
	No	32	86.5

Table 3 Comparison of proportion of the subjects categorised based on lung ultrasound score over the period of study

Lung ultrasound score	Score 0 (normal)		Score 1 (well separated B-lines)		Score 2 (coalescent B-lines)		Score 3 (consolidation)		P value
	n	%	n	%	n	%	n	%
Baseline (n = 37)	0	0.0	15	40.5	16	43.2	6	16.2%	-
After trial 1 (n = 37)	17	45.9	14	37.8	6	16.2	0	0.0	< 0.001
After trial 2 (n = 20)	15	75.0	4	20.0	1	5.0	0	0.0	< 0.001
After trial 3 (n = 5)	5	100.0	0	0.0	0	0.0	0	0.0	0.032

Table 4 Validity of lung ultrasound scores in assessing the aeration of lung after positive end expiratory pressure trial of 5 cm of water¹

Trial 1 (n = 37)		SpO2
		100.0%		≤ 99.0%		Total
		n	%	n	%	n	%
Lung ultrasound score	100.0%	16	43.2	1	2.7	17	45.9
	≤ 99.0%	0	0.0	20	54.1	20	54.1
	Total	16	43.2	21	56.8	37	100.0

¹Kappa agreement = 0.945.

Sensitivity = 100.0%, Specificity = 95.2%, Positive predictive value = 94.1%, Negative predictive value = 100.0%.

Table 5 Association between indications of mechanical ventilation and positive end expiratory pressure requirement to achieve 100% oxygen saturation

Mechanical ventilation indications	After trial 1 (n = 37)				After trial 2 (n = 20)				After trial 3 (n = 5)
	Yes		No		Yes		No		Yes		No
	n	%	n	%	n	%	n	%	n	%	n	%
Airway protection	10	76.9	3	23.1	2	100.0	0	0.0	0	0.0	0	0.0
Alveolar filling defect	0	0.0	4	100.0	1	25.0	3	75.0	2	100.0	0	0.0
Impaired central drive	3	75.0	1	25.0	1	100.0	0	0.0	0	0.0	0	0.0
Post anesthesia recovery	3	42.9	4	57.1	3	75.0	1	25.0	0	0.0	0	0.0
Pulmonary vascular defect	0	0.0	2	100.0	1	50.0	1	50.0	0	0.0	0	0.0
Respiratory muscle weakness	0	0.0	2	100.0	1	50.0	1	50.0	1	100.0	0	0.0
Restrictive ventilatory defect	0	0.0	5	100.0	3	60.0	2	40.0	1	50.0	1	50.0
P value	0.007				0.598				0.392