eComment. Haemodynamic goal-directed therapy in cardiac surgery

Giglio et al. [1] are to be commended for trying to answer an important question that frequently arises in clinical practice: what are the effects of applying perioperative goal-directed therapy on postoperative complications in patients undergoing cardiac or vascular surgery? The authors concluded from this meta-analysis that perioperative goal-directed therapy prevents postoperative complications in cardiac surgery patients, but produces no benefit in vascular surgery. I entirely agree with their opinion and would like to add a brief comment related to the implementation of this strategy in cardiac surgery. Goal-directed therapy is a term used to describe the guidance of intravenous fluid and vasopressors with or without inotropic drugs by using cardiac output or related parameters to optimize the circulatory status in the immediate cardiac surgery patients. This concept was first propagated by Shoemaker et al. in 1988 [2], who found a significant reduction in mortality and hospital stay in high-risk surgical patients by avoiding a tissue oxygen debt perioperatively. The anaesthetic management consisted of early fluid loading with or without dobutamine to increase cardiac output to supranormal values. Conventional haemodynamic monitoring in cardiac surgery includes variables such as heart rate, mean arterial pressure, central venous pressure and urine output. Advanced monitoring is essential in goal- directed therapy. It comprises central venous oxygen saturation with one of the following technologies: pulmonary artery catheterization, oesophageal Doppler flowmetry, single trans-pulmonary thermodilution [3]. All these monitoring technologies can measure or calculate the cardiac output or the stoke volume and other advanced parameters with some degree of invasiveness. A previously written algorithm is usually implemented by hospital staff to early detect low cardiac output and to apply the protocol [4]. This meta-analysis demonstrates that applying goal-directed therapy by using advanced monitoring technologies reduces postoperative complications in elective cardiac surgery patients albeit without improvement in mortality. This is not in line with the 2011 ACCF/AHA guideline for coronary artery bypass graft (CABG) surgery, which recommends the placement of a pulmonary artery catheter before induction of anaesthesia only in patients with acute haemodynamic instability or cardiogenic shock. However, it is considered to be reasonable in clinically stable patients undergoing CABG after consideration of baseline patient risk, the planned surgical procedure, and the practice setting [5]. Continuing investigations into this area are warranted to better clarify the link between haemodynamic optimization and improved outcome in patients undergoing elective cardiac surgery. Conflict of interest: none declared