Introduction. Postoperative pulmonary complications occur in 5–70% of cases in surgical patients and are accompanied by significant short-term and long-term mortality. The purpose is to conduct a comparative analysis of the relationship between the frequency of postoperative pulmonary complications, the degree of surgical risk and the development of interstitial edema in different modes of infusion therapy in patients with moderate and high surgical risk with acute abdominal pathology. Materials and Methods. We examined 200 patients with acute abdominal pathology, operated on urgently by laparatomy access. Patients were divided into groups according to the degree of surgical risk, subgroups were formed taking into account the regimen of infusion therapy. Subgroup 1.1 (n = 50) included patients who received infusion therapy in a liberal regimen; in subgroup 1.2 (n = 50), infusion therapy was performed in a restriction regimen. Subgroup 2.1 (n = 50) consisted of patients who received goal-direct infusion therapy, subgroup 2.2 (n = 50) – restrictive infusion therapy. The non-invasive bioelectric rheography method was used to evaluate the performance of the body's water sectors, sonographically determine the degree of fluid accumulation in the extravascular pulmonary fluid space, postoperative pulmonary complications were verified on the basis of clinical, laboratory and radiological data. In the total cohort of patients we noted 10.5% of postoperative pulmonary complications. In the postoperative period of the liberal regime of infusion therapy was accompanied by an increase of interstitial volume by 146% (p<0.04) and 159% (p<0.02) of norm, a moderate degree of accumulation of fluid within the pulmonary space (R=0,86, p=0.04) and had a strong direct relationship with the development 16% of postoperative pulmonary complications (R=0.79, p=0.002). The absence of interstitial edema on the background of the restrictive regime of infusion therapy, normal sonographic pattern of light when the frequency of postoperative pulmonary complications 6% in the group of moderate surgical risk of 10% in the group of high surgical risk. Goal-direct infusion therapy generates an increase in the volume of interstices on the first day, the accumulation of fluid within the primary space of mild to 3 days and combined with a 10% development of pulmonary complications after surgery. Discussion. In patients with acute abdominal pathology of middle and high surgical risk the overall incidence of postoperative pulmonary complications is 10.5%, of which 80.9% of all cases are associated with pneumonia. Moderate surgical risk patients had a different infusion therapy's affects to the development of postoperative pulmonary complications; a liberal regime is accompanied by the development of interstitial edema, increased extravascular fluid in the lungs and incidence of pulmonary complications in 16%, restrictive mode preserves the volume of the interstices within the boundaries of the rules during postoperative period and reduces the risks of pulmonary complications to 6%. High surgical risk patients with acute abdominal pathology, postoperative period is complicated by development of pulmonary complications in 10% of cases due to increased interstitial volume and pulmonary extravascular fluid mild in the first day when targeted mode of infusion therapy limits the development of interstitial edema during all the postoperative period in the restrictive mode of infusion therapy.