SAFETY-MODE RESPIRATORY SUPPORT IN NOSOCOMIAL PNEUMONIA

Abstract

Diagnostic criteria for and approaches to differentiated treatment for acute respiratory distress syndrome (ARDS) in nosocomial pneumonia (NP) have been elaborated, but approaches to preventing this syndrome in the presence of risk factors have not been investigated. Safety-mode mechanical ventilation (MV) (protective MV) is the most probable way of preventing ARDS in NP. Objective: to evaluate the efficiency of MV with safety parameters in preventing ARDS in NP in patients with surgical abdominal infection. Subjects and methods. This retrospective unicentric study was conducted at the clinical bases of the V. A. Negovsky Research Institute of General Reanimatology in 2013—2014. During a retrospective analysis, the patients were divided into two groups: 1) safe MV — after NP was diagnosed, the patients underwent safetymode MV (tidal volume (TV) 6—8 ml/kg); 2) standard MV — after NP was diagnosed, the patients were on MV with traditional parameters (TV 8—10 ml/kg). The incidence of ARDS in the patient groups was taken as a main criterion for the efficiency of safetymode respiratory support. The duration of MV, the length of stay in an intensive care unit, and 30day mortality rates were estimated as secondary criteria for the efficiency of safety-mode respiratory support. The findings were statistically analyzed using a Statistica 7.0 package. The data were expressed as the median (± 25—75 percentiles interquartile range (IQR)). The difference at p<0.05 was considered signif icant. >Results. Comparison of oxygenation index (OI) and extravascular lung water index (ELWI) showed that there were natural significant differences between the safe MV and standard MV groups in these indicators, beginning from day 2 of the investigation. The standard MV group displayed a significant decrease in OI and an increase in ELWI at 7 days versus at day 1 of the investigation. In the safe MV group, TV was naturally lower than that in the standard MV group on days 1, 3, and 5 of the study. From day 3, the statistical lung compliance was lower in the standard MV group than that in the safe MV group, which was linked to the development of ARDS in the patients in this group. From day 3, the peak airway pressure was higher in the standard MV group than that in the safe MV group. From this time, the plateau airway pressure was higher in the standard MV group than that in the safe MV group. There were significant differences in the incidence rate of ARDS in NP in the patient groups: ARDS developed in 6 (15.0%) and 20 (67.1%) NP patients who underwent safe and standard MV, respectively (p=0.0001, Fisher's exact test). The NP patients who used MV with safety parameters were recorded lower lengths of MV (14.8±6.2 days) and stay in an intensive care unit (19.2±6.0 days) than those who had standard MV (20.0±6.3 and 23.9±7.7 days) (Fig. 9). There were significant differences in mortality rates between the patient groups in the NP patients on safe MV whose mortality was 27.5% (n=11); this in the NP patients on standard MV was 46.7% (n=14) (p=0.0046, Fisher's exact test). Conclusion. MV with safety parameters allows for preventing ARDS in NP in patients with surgical abdominal infection, which improves treatment outcomes.

Keywords

• nosocomial pneumonia
• acute respiratory distress syndrome
• mechanical ventilation
• prevention