Short-term outcome after open-heart surgery for severe chronic rheumatic heart disease in a low-income country, with comparison with an historical control group: an observational study.

OBJECTIVES: Rheumatic heart disease (RHD) is a major burden in low-income and middle-income countries (LMICs). Cardiac surgery is the only curative treatment. Little is known about patients with severe chronic RHD operated in LMICs, and challenges regarding postoperative follow-up are an important issue. At Tikur Anbessa Specialised Hospital, Addis Ababa, Ethiopia, we aimed to evaluate the course and 12-month outcome of patients with severe chronic RHD who received open-heart surgery, as compared with the natural course of controls waiting for surgery and undergoing only medical treatment. METHODS: Clinical data and outcome measures were registered in 46 patients operated during five missions from March 2016 to November 2019, and compared with the first-year course in a cohort of 49 controls from the same hospital's waiting list for surgery. Adverse events were death or complications such as stroke, other thromboembolic events, bleeding, hospitalisation for heart failure and infectious endocarditis. RESULTS: Survival at 12 months was 89% and survival free from complications was 80% in the surgical group. Despite undergoing open-heart surgery, with its inherent risks, outcome measures of the surgical group were non-inferior to the natural course of the control group in the first year after inclusion on the waiting list (p≥0.45). All except six surgical patients were in New York Heart Association class I after 12 months and 84% had resumed working. CONCLUSIONS: Cardiac surgery for severe chronic RHD is feasible in LMICs if the service is structured and planned. Rates of survival and survival free from complications were similar to those of controls at 12 months. Functional level and resumption of work were high in the surgical group. Whether the patients who underwent cardiac surgery will have better long-term prognosis, in line with what is known in high-income countries, needs to be evaluated in future studies.

Isoflurane in contrast to propofol promotes fluid extravasation during cardiopulmonary bypass in pigs.

BACKGROUND: A highly positive intraoperative fluid balance should be prevented as it negatively impacts patient outcome. Analysis of volume-kinetics has identified an increase in interstitial fluid volume after crystalloid fluid loading during isoflurane anesthesia. Isoflurane has also been associated with postoperative hypoxemia and may be associated with an increase in alveolar epithelial permeability, edema formation, and hindered oxygen exchange. In this article, the authors compare fluid extravasation rates before and during cardiopulmonary bypass (CPB) with isoflurane- versus propofol-based anesthesia. METHODS: Fourteen pigs underwent 2 h of tepid CPB with propofol (P-group; n = 7) or isoflurane anesthesia (I-group; n = 7). Fluid requirements, plasma volume, colloid osmotic pressures in plasma and interstitial fluid, hematocrit levels, and total tissue water content were recorded, and fluid extravasation rates calculated. RESULTS: Fluid extravasation rates increased in the I-group from the pre-CPB level of 0.27 (0.13) to 0.92 (0.36) ml·kg·min, but remained essentially unchanged in the P-group with significant between-group differences during CPB (pb = 0.002). The results are supported by corresponding changes in interstitial colloid osmotic pressure and total tissue water content. CONCLUSIONS: During CPB, isoflurane, in contrast to propofol, significantly contributes to a general increase in fluid shifts from the intravascular to the interstitial space with edema formation and a possible negative impact on postoperative organ function.

Surface cooling versus core cooling: comparative studies of microvascular fluid- and protein-shifts in a porcine model.

OBJECTIVE: To describe how surface cooling compared with core cooling influences fluid and protein distribution, vascular capacity and hemodynamic variables. METHODS: 14 anesthetized piglets were, following 60 min normothermic stabilization, randomly cooled by surface cooling (ice-sludge) (n=7) or core cooling (endovascular cooling) (n=7) to about 28 degrees C. Fluid balance, hemodynamic variables, colloid osmotic pressures (plasma/interstitial fluid), hematocrit, serum-albumin and -protein concentrations, intracranial pressure (ICP) and cerebral metabolic markers of ischemia were measured. Fluid shifts and changes in albumin and protein masses were calculated. At the end total tissue water content was assessed and compared with a normothermic control group. RESULTS: Both cooling modes induced an increase in fluid extravasation rate from 33.9 (31.9) and 27.8 (28.0) to 109.0 (16.5) (P=0.006) and 95.6 (29.1) ml/kg/min x 10(-3) (P=0.024) in the surface-cooled and core-cooled groups, respectively. Albumin extravasation was reflected by a significant drop in the albumin mass from 148.8 (11.7) to 111.4 (10.3) (P=0.000) and from 163.4 (27.8) to 136.8 (19.0) g/kg x 10(-2) (P=0.001) in the surface-cooled and core-cooled animals, respectively. Similar findings were obtained concerning serum-protein masses. The total tissue water content increased in most organs including brain in both study groups compared with a control. ICP and cerebral metabolic markers remained normal in both groups. CONCLUSION: Rapid lowering of body core temperature results in extravasation of water and proteins. The amount of extravated fluid and proteins is similar either cooling is a result of surface cooling or core cooling. Cold-induced fluid extravasation is associated with edema in most tissues including brain.