[Clinical and economic aspects of laparoscopic surgery for acute cholecystitis in delayed presentation]. / Kliniko-ekonomicheskie aspekty laparoskopicheskikh operatsii pri ostrom kholetsistite v usloviyakh pozdnei gospitalizatsii.

OBJECTIVE: To study the clinical and economic features of laparoscopic surgery for acute cholecystitis in delayed presentation. MATERIAL AND METHODS: A prospective non-randomized study (2020-2021) included 101 patients (73.2% (n=74) men and 26.8% (n=27) women, mean age 58±14.9 years) with acute cholecystitis who underwent laparoscopic cholecystectomy. Cost-effectiveness analysis of laparoscopic cholecystectomy at various periods after clinical manifestation was performed. RESULTS: Surgical treatment within 72 hours was performed in 15% (n=16) of cases (group 1), within 4-10 days - in 57.5% (n=58) (group 2), after 10 days - in 26.7% (n=27) of patients (group 3). Overall incidence of postoperative complications was 2.9%, postoperative mortality - 1.9% (two patients died from widespread peritonitis). Surgery time was 70 [65-83], 85 [69-110] and 115 [80-125] min (H=15.55, p<0.001), hospital-stay - 6 [5-7], 9 [7-10] and 11 [7-14] days, respectively (H=21.86, p<0.001). Cost of direct (medical and non-medical) treatment amounted to 29484 [27 509-33 885], 41265 [34 306-48 301] and 50591 [37 069-62 483] rubles, respectively (H=29.71, p<0.001)). CONCLUSION: Delayed hospitalization and surgical treatment of acute cholecystitis after 72 hours are accompanied by higher treatment costs by 29% in the period up to 10 days and by 58% after 10 days. These results require further validation and adjustment in large samples.

Multiple scattering effects in Doppler optical coherence tomography of flowing blood.

We investigate the effect of multiple scattering on the optical coherence tomography (OCT) signal and the Doppler OCT signal of flowing blood. Doppler OCT measurements at 1300 nm are performed on flowing diluted porcine blood with hematocrit ranging between 0% and 15%. Measured blood hematocrit and mean red blood cell volume are used to calculate, using the discrete dipole approximation model, the (single) scattering coefficient and scattering anisotropy of blood. Monte Carlo simulations, based on the calculated scattering coefficients and scattering anisotropies, are compared to Doppler OCT measurements for hematocrit smaller than 10%. Good quantitative agreement between Doppler OCT measurements and Monte Carlo simulations is observed. Our measurements, calculations and simulations explain the relatively low attenuation coefficients and well preserved flow profiles measured with Doppler OCT for flowing blood. Monte Carlo simulations demonstrate the effect of the scattering anisotropy of the medium on the strength of multiple scattering effects in Doppler OCT signals. With increasing scattering anisotropy the OCT attenuation decreases; the distortion of the flow profile is strongest at intermediate scattering anisotropies (≈0.6).