N-Acetylcysteine Enhances Recovery From Acute Lung Injury in Man – Results
Initial homogeneity assessment of the two groups was performed by t test and x2 analysis. The before and after comparisons were done with the sign test, the paired t test, and the Wilcoxon-Pratt test depending on the distribution of the data. Between-group comparisons were performed with the X2 test, the Student t test, and the Wilcoxon-Man-Whitnev W test according to the distribution of the data. Data are presented as mean values ± standard deviations unless specified otherwise.
Characterization of Patients
A total of 61 patients (47 men and 14 women) were recruited for the study (Table 1). All were considered evaluable for data analysis. Thirty-two patients received NAC and 29 received placebo. The two groups were well matched for demographic characteristics on trial entry. The SAPS for severity of disease was 10.8 ± 4.6 in the NAC group and 10.9 ± 4.8 in the placebo group (x ± SD, not significant [NS]). On admission, the lung injury score was 1.39 ± 0.95 in the NAC group, a value not significantly different compared with the placebo group of 1.11 ± 1.08. Risk factors and associated conditions were similar in the two groups. Three patients in each group developed severe lung injury (ARDS) defined as a LIS above 2.S. Seven of 32 patients (22 percent) in the treatment group and 10 of29 (35 percent) in the placebo group died (NS). During the study, adverse events due to NAC were not detected. canadianfamilypharmacy
Ventilatory Support, FIo2, Lung Function
Twenty-two patients in each group (69 percent in the NAC and 76 percent in the placebo group) required ventilatory support at ICU admission (day 0); at day 3, the percentage of patients receiving ventilatory support was significantly reduced in the treated group from 69 to 17 percent (p = 0.01), whereas in the placebo group this decrease (from 76 to 48 percent) was not significant, p = 0.01 between groups (Fig 1). At day 0, there was no significant difference between the two groups with regard to FIo2 administered. At day 3, the Flo, was significantly decreased in the NAC group (0.29 ± 0.09 vs 0.48 ± 0.24 at admission; p < 0.01) whereas in the placebo group there was no significant decrease (0.35 ± 0.11 vs 0.45 ± 0.20). The difference in FIo2 between the two groups was significant on day 3 (p < 0.05). The oxygenation index PaOJ Flo, was similar at admission for both groups (255 ±113 mm Hg in the NAC vs 248 ± 99 mm Hg in the placebo group, NS) and increased significantly in the NAC group reaching 294 ± 99 mm Hg on day 3 (p<0.05). No significant change was noted in the placebo group (Fig 2). There was no statistical difference in PaO./FIo, between the NAC- and placebo-treated patients. The lung injury score decreased in the NAC group from 1.39 ± 0.95 to 0.67 ± 0.70, p < 0.01, between ICU admission and day 10. No significant change was observed in the placebo group. At ICU admission, the mean chest radiograph score was higher in the NAC than in the placebo group (1.8 ± 1.1 vs 1.1 ± 1.1; p < 0.05). Up to day 3 this score increased in the placebo group (p < 0.05), whereas it did not change significantly in the NAC group up to day 3, but decreased until the discharge from the ICU (from 1.8 ± 1.1 at admission to 1.1 ± 1.1, p < 0.01).
Table 1—Characteristics of Patient Groups, SAPS Scale and Lung Injury Scare (IIS) at Admission to the ICU
|No. of patients||32||29|
|Age, у||46.6 ±19.7||48.1 ±21.9|
|Primary risk factors (n)|
|Multiple trauma and||7||5|
|Sepsis and aspiration||1||3|
|Associated diseases and complications|
|Acute renal failure||3||3|
|Simplified acute physiology score*||10.8 ±4.60||10.9 ±4.80|
|ICU stay, days, mean ± SD||11.3 ±10.5||12.2 ±9.6|
|Development of ARDS, n||3||3|
|Mortality rate, n (%)||7 (22)||10 (35)|
Figure 1. Percentage of patients requiring mechanical ventilatory support in the N-acetylcysteine (NAC) and placebo group. Evolution from days 0 (admission) through day 3 (end of NAC treatment). The triangle identifies a significant difference between the two groups at day 3 (p = 0.01). The asterisks identify a significant difference in the treated group on day 2 and 3 vs admission (day 0; p = 0.01).
Figure 2. Mean values±SEM of PaO/FIo2 (hypoxemia index, 22) at admission (day 0) through day 3 (end of N-acetylcysteine [NAC] treatment) and the day of discharge from the ICU in treated and placebo-treated patients. One asterisk indicates p < 0.05 vs day 0; two asterisks, p = 0.01 vs day 0.