Respiratory mechanics, ventilator-associated pneumonia and outcomes in intensive care unit

Table 1 Characteristics of the sample

Sample characteristics (n = 120)	Results
Age (yr)
Mean ± SD	58.5 ± 19.4
Minimum-maximum	15-91
Gender n (%)
Male	69 (57.5)
Female	51 (42.5)
APACHE II (score)
Mean ± SD	27.4 ± 6.7
Minimum–maximum	8-47
Risk of mortality (%)-APACHE II
Mean ± SD	61.8 ± 7.3
Admission diagnoses n (%)
Diseases of the circulatory system	43 (35.8)
Diseases of the respiratory system	15 (12.5)
Lesions, poisoning and other consequences of external causes	14 (11.7)
Gastrointestinal diseases	8 (6.7)
Unclassified signs and symptoms	8 (6.7)
Diseases of the genitourinary system	7 (5.8)
Neoplasia	4 (3.3)
Nervous system disorders	4 (3.3)
Infectious and parasitic diseases	3 (2.5)
Endocrine, nutritional and metabolic diseases	3 (2.5)
Other	11 (9.2)
Mechanical ventilators n (%)
1Servo S	89 (74.2)
1Servo 900	203 (16.7)
1Dixtal	11 (9.2)

¹Source: Prepared by the author, 2013.

Table 2 Respiratory mechanics and oxygenation index on the 1^st and 5^th day

Oxygenation index	Mean ± SD	Minimum-maximum
Respiratory mechanics
1st day (n = 120)
PaO2/FiO2 (mmHg)	236.0 ± 97.6	47.0-465.7
Compliance-VCV (mL/cm H2O)	40.9 ± 12.8	15.0-88.0
Resistance-VCV (cm H2O/L/s)	13.2 ± 4.9	4.1-28.6
Compliance-PCV (mL/cm H2O)	35.0 ± 10.0	15.0-62.0
Resistance-PCV (cm H2O/L/s)	27.3 ± 16.2	9.1-131.1
5th day (n = 77)
PaO2/FiO2 (mmHg)	241.7 ± 88.7	58.0-445.0
Compliance-VCV (mL/cm H2O)	39.7 ± 13.2	18.0-83.0
Resistance-VCV (cm H2O/L/s)	13.8 ± 6.0	5.3-43.0
Compliance-PCV (mL/cm H2O)	32.9 ± 9.3	13.5-52.5
Resistance-PCV (cm H2O/L/s)	26.4 ± 11.8	6.2-73.5

Source: Prepared by the author, 2013. VCV: Volume-controlled ventilation; PCV: Pressure-controlled ventilation.

Table 3 Numeric variables and ventilator-associated pneumonia

Variables	VAP		P value
	Yes	No
APACHE II1	29.2 ± 5.6	26.5 ± 7.1	0.026
Age (yr)	57.1 ± 19.1	59.2 ± 19.6	0.565
1st day (n = 120)
PaO2/FiO2 (mmHg)1	232.3 ± 79.9	237.8 ± 105.2	0.756
Compliance-VCV (mL/cmH2O)	43.1 ± 14.9	39.8 ± 11.6	0.365
Resistance-VCV (cmH2O/L/s)	13.7 ± 5.0	13.0 ± 4.8	0.594
Compliance-PCV (mL/cmH2O)1	34.8 ± 10.4	35.1 ± 9.8	0.879
Resistance-PCV (cmH2O/L/s)	23.6 ± 10.3	29.0 ± 18.1	0.114
5th day (n = 77)
PaO2/FiO2 (mmHg)1	244.1 ± 94.1	240.2 ± 86.1	0.850
Compliance-VCV (mL/cmH2O)	43.3 ± 14.0	37.6 ± 12.3	0.092
Resistance-VCV (cmH2O/L/s)	13.9 ± 6.8	13.8 ± 5.5	0.996
Compliance-PCV (mL/cmH2O)1	33.6 ± 8.9	32.5 ± 9.6	0.606
Resistance-PCV (cmH2O/L/s)	27.1 ± 11.7	25.9 ± 12.0	0.777
(n = 120)
Duration of MV (d)	18.4 ± 14.9	10.7 ± 6.8	0.001
Length of stay in ICU (d)	20.4 ± 15.3	12.8 ± 7.6	0.003

Mann-Whitney U-test;

¹Student’s t-test. Source: Prepared by the author, 2013. VAP: Ventilator-associated pneumonia; VCV: Volume-controlled ventilation; PCV: Pressure-controlled ventilation; MV: Mechanical ventilation; ICU: Intensive care unit.

Table 4 Numeric variables and death

Variables	Outcome		P value
	High	Death
APACHE II1	27.0 ± 7.6	27.7 ± 5.8	0.606
Age (yr)	51.1 ± 19.9	65.4 ± 16.1	< 0.001
1st day (n = 120)
PaO2/FiO2 (mmHg)1	263.1 ± 100.9	210.7 ± 87.8	0.003
Compliance-VCV (mL/cm H2O)	43.5 ± 12.5	38.4 ± 12.6	0.015
Resistance-VCV (cm H2O/L/s)	13.3 ± 4.3	13.2 ± 5.4	0.935
Compliance-PCV (mL/cm H2O)1	36.6 ± 9.8	33.6 ± 9.9	0.103
Resistance-PCV (cm H2O/L/s)	25.0 ± 10.5	29.4 ± 20.0	0.416
5th day (n = 77)
PaO2/FiO2 (mmHg)1	268.8 ± 81.9	214.7 ± 87.9	0.004
Compliance-VCV (mL/cm H2O)	40.7 ± 12.7	38.7 ± 13.7	0.356
Resistance-VCV (cm H2O/L/s)	14.2 ± 5.0	13.5 ± 6.9	0.22
Compliance-PCV (mL/cm H2O)1	34.1 ± 9.4	31.8 ± 9.1	0.282
Resistance-PCV (cm H2O/L/s)	25.7 ± 10.8	27.1 ± 12.9	0.76
(n = 120)
Duration of MV (d)	14.5 ± 12.4	11.9 ± 8.6	0.212
Length of stay in ICU (d)	18.3 ± 12.5	12.4 ± 8.9	< 0.001

Mann-Whitney U-test;

¹Student’s t-test. Source: Prepared by the author, 2013. VCV: Volume-controlled ventilation; PCV: Pressure-controlled ventilation; MV: Mechanical ventilation; ICU: Intensive care unit.

Table 5 Relative risk for ventilator-associated pneumonia and outcomes

Variables	RR	95%CI	P value
VAP
APACHE II above the average	1.62	1.03-2.55	0.016
Male gender	1.56	1.18-2.08	0.004
Resistance worsening-PCV	1.85	1.16-2.94	0.01
Outcome: Death
Age above the average	2.08	1.34-3.23	0.001
Compliance-VCV below average on 1st day	1.49	1.00-2.21	0.032
ICU stay below the average	2.05	1.28-3.28	0.001

Source: Prepared by the author, 2013. VAP: Ventilator-associated pneumonia; VCV: Volume-controlled ventilation; PCV: Pressure-controlled ventilation; ICU: Intensive care unit.