Utility and safety of draining pleural effusions in mechanically ventilated patients: a systematic review and meta-analysis

Table 3 Summary of studies of pulmonary mechanics after thoracentesis in mechanically ventilated patients

Study	Proportion Mechanically Ventilated	N	Time of Outcome Measurement	Variable	Outcome ^a
					Before	After	P-value
Ahmed 2004	100%	22	<1 hour before and after thoracentesis	Peak inspiratory pressure (cm H₂O)	34.9 ± 8.4	35.9 ± 12.5	0.64^b
				Respiratory rate	19.4 ± 6.5	15.5 ± 6.3	0.03
Doelken 2006	100%	9	Immediately before and after procedure	Peak inspiratory pressure (cm H₂O)	43.8 ± 13.7	40.8 ± 10.6	0.08
				Plateau pressure (cm H₂O)	20.0 ± 9.0	17.8 ± 5.6	0.19
				Dynamic compliance (L/cm H₂O)	14.5 ± 5.3	15.2 ± 5.0	0.12
				Ventilator work per cycle (Joules)	3.42 ± 1.05	2.99 ± 0.81	0.01
Talmor 1998	100%	19	Immediately before and after procedure	Peak inspiratory pressure (cm H₂O)	44.3 ± 13.9	42.9 ± 18.7	0.74^b
				Dynamic compliance (L/cm H₂O)	27.1 ± 15.3	35.7 ± 30.5	< 0.05

^aValues are reported as mean ± standard deviation.
^bP-value not provided in the original paper; we calculated the P-value based on the data provided, assuming a correlation between the before and after measurements of 0.4.

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