Secondary Outcomes
Three secondary outcomes, in hospital mortality, requirement for renal replacement therapy and length of stay (LOS) in ICU were also assessed. Regarding in hospital mortality, a total of 1055 patients in 8 of studies were observed. Meta-analytic estimates for in hospital mortality showed that there was no statistically significant difference between patients treated with NAC and without, as showed in Fig 7 (OR: 0.85, 95% CI: 0.43-1.68)
Regarding the requirement for renal replacement therapy, a total of 686 patients in 4 of the studies were assessed. Meta-analytic estimates did not show any significant benefit of NAC in reducing the requirement for renal replacement therapy as showed in Fig 8 (OR: 1.05, 95% CI: 0.38-2.92)
Seven studies (1042 patients) reported length of stay in ICU. All studies reported the exact length of stay in ICU except one study which reported the number of patients that had an ICU stay longer than 4 days. Three studies reported the mean length of stay and standard deviation. Two studies reported the median length of stay and interquartile range. One study reported the median length of stay and total range. For meta analytic estimates to be conducted, a normal distribution had to be assumed for the three studies that reported the median length of stay. Thus, the median was approximated to be the mean, and standard deviation was approximated by dividing the interquartile range by 1.35 and the total range by 4. Meta analytic estimates of studies that reported the mean and standard deviation and studies with approximated mean and standard deviation were conducted separately. Both meta analytic estimates did not show any benefit of NAC in reducing the length of stay in ICU as showed in Fig 9A (Mean Difference: 0.27, 95% CI: -2.25-2.79) and Fig 9B (Mean Difference: 0.00, -0.27-0.27).