Intraoperative haemodynamic optimisation therapy with venoarterial carbon dioxide difference and pulse pressure variation – does it work?

BACKGORUND Current evidence suggests that intraoperative goal-directed haemodynamic therapy (GDT) should be considered for high-risk patients undergoing major gastrointestinal surgery. We aimed to evaluate if an algorithm using venoarterial carbon dioxide difference (CO2 gap) and pulse pressure variation (PPV) as therapeutic targets during GDT would decrease the major complications after gastrointestinal surgery. METHODS This was a before-and-after study (n = 204) performed in a tertiary hospital on patients who underwent elective open major gastrointestinal surgeries. The inclusion criteria were surgeries expected to last more than two hours, family and physician's agreement on total postoperative support, and survival expectancy of at least three months. The exclusion criteria were previous haemodynamic instability, presence of infection, cardiac arrhythmias, and emergency surgery. In the intervention group (IG), an algorithm was applied using fluids, dobutamine, and noradrenaline during the intraoperative period aiming at MAP > 65 mm Hg, SpO2 > 95%, CO2 gap < 6 mm Hg, and PPV < 13%. The control group (CG) comprised consecutive eligible patients who were operated by the same team before the institution of the algorithm. RESULTS The rates of moderate and severe postoperative complications were lower in the IG (11% vs. 23%; IC: RR = 0.47, 95% CI: 0.246-0.929; P = 0.025). The respective 90- and 180-day mortality rates in the IG and CG were 9.8% vs. 22.5% (P = 0.014) and 12.6% vs. 25.5% (P = 0.020). CONCLUSIONS An algorithm aiming to minimise the CO2 gap and normalise PPV was feasible and effective in decreasing rates of moderate and severe complications after surgery in high-risk patients.