Diferença veno-arterial de CO2 como alvo terapêutico na terapia dirigida por metas em pacientes submetidos às cirurgias não cardíacas de grande porte

Abstract

In the next decades, an expansion of surgical services to address unmet needs is likely to increase total global deaths because there will be more deaths in the postoperative period, from which 1.9 million would be in low-middle income countries. Current evidence suggests that intraoperative management of major elective gastrointestinal surgery should consider cardiac output (CO) monitoring and goaldirected therapy. However, cost restrains may determine low adherence to these practices in low resource settings. We hypothesized that central veno-arterial difference of CO2 [P(v-a)CO2] could serve as a surrogate marker for CO monitoring during GDT. Objective: We aimed to evaluate the impact of the use of P(v-a)CO2 as a surrogate of cardiac output in an algorithm of GDT on major complications and 30, 90, 180 day mortality. Casuistics and Method: The study was a quasi-randomized (before and after) controlled and explanatory trial performed in a tertiary university hospital in patients undergoing elective major gastrointestinal surgeries. In the interventional group a treatment algorithm aiming to keep mean arterial pressure > 65 mmHg, SpO2 > 94%, CO2 gap lower than 6 mmHg and pulse pressure variation (DPP) lower than 13% using fluids, dobutamine and noradrenaline was applied in addition to the standard practice. The control group comprised all the consecutive patients that received traditional standard of care from the same team of surgeons and anesthesiologists in the period before the intervention phase. Results: A total of 204 patients were included in this study; 102 in each group. Measurements of P(v-a)CO2 were lower in the GDT group than in Control group at T0 (30-60 min after induction): 5.9 ± 2.1 vs. 6.7 ± 2.7 mmHg, p=0.008; T1 (2 h ± 30min): 6.4 ± 2.6 vs. 7.0 ± 2.2 mmHg, p = 0.084 and T2 (4 h ± 30min): 5.9 ± 2.9 vs. 7.1 ± 3.4 mmHg, p = 0.043. Central venous saturation (ScvO2) was significantly higher throughout the intraoperative period in the GDT group. The number of patients with major complications was lower in GDT group than in the control group and there was a significant decrease in 90-day mortality in the GDT group (22.5% vs. 9.8%, p=0.014) maintained in 180-days of postoperative (24.5% CG vs 12.7% IG, p = 0.020). Conclusion: The use of algorithm aiming the minimization of P(v-a)CO2 was feasible and effective to decrease moderate and severe complications as well as mortality in high risk surgical patient. Keywords: Goal Direct Therapy, Perioperative Hemodynamic Optimization, Tissue Perfusion, Fluid-Responsiveness, High-risk Surgical Patients, Arterial-Venous Difference of CO2.