Table 3.

Ventilator-Derived Indices of Airway Resistance and Respiratory System Compliance.

Patient no.	Ppeak (cm H2O)	Pplat (cm H2O)	AutoPEEP (cm H2O)*	Presist (cm H2O)*	Airway resistance (cmH2O/L/sec)*	Driving pressure (cm H2O)*	Cstat (ml/cmH2O)*
Patient 1	45	25	1	20	26.4	10	30
Patient 2	44	23	1	21	22.2	10	38
Patient 3	37	24	0	13	14.4	12	30.83
Patient 4	34	19	4	15	16.8	7	58.57
Patient 5	38	21	4	17	18	5	76
Patient 6	43	27	1	16	16.2	12	29.16
Patient 7	51	29	–1	22	23.4	15	18.67
Patient 8	48	24	0	24	25.71	9	46.67
Patient 9	40	20	1	20	22.86	9	38.89
Patient 10	49	25	1	24	24	12	29.17
Patient 11	38	21	0	17	17	7	42.86
Patient 12	41	25	0	16	17.49	11	29
Mean (±SD)	42 (±5)	24 (±3)	1 (±1)	19 (±4)	20 (±4)	10 (±3)	39 (±16)

Abbreviations: Cstat, static compliance; Ppeak, peak pressure; Pplat, plateau pressure; Presist, resistive pressure.

* Calculation of indices: AutoPEEP = intrinsic PEEP – extrinsic PEEP; Presist = Ppeak – Pplat; airway resistance = (Ppeak – Presist)/flow rate; driving pressure = Pplat – intrinsic PEEP; Cstat = Vt/driving pressure.