Perioperative care of the cardiac patient in non-cardiac surgery

The anaesthesiologist should take a strong part in the perioperative care of patients with cardiac disease. The interaction between the different specialists may determine the outcome of the procedure. In order to prepare the patient prior to non-cardiac surgery, the knowledge of the anaesthesiologist is important for the risk assessment and for the optimal preparations. Skills and knowledge of physiology and patho-physiology are vital for the intra-operative management and also for the postoperative follow-up, including pain control, cardio-respiratory management, fluid therapy, and nutrition. Patients with cardiac disease gain from the optimization of organ dysfunction. Unfortunately, there is a lack of strong evidence-based data supporting the choice for a particular perioperative approach. Several options are therefore available to the anaesthesiology team. Many studies and randomized trials on a limited number of patients have addressed the potential relation between anaesthetic management and patient outcome. However, sufficiently powered randomized trials showing the advantage of a specific perioperative approach are still lacking. Few studies specifically have investigated the outcome of cardiac patients after non-cardiac surgery. Patients undergoing vascular surgery have often cardiac disease. Vascular surgery patients have therefore been examined frequently. Patients in cardiac failure tend to have elevated levels of N-terminal pro- brain natriuretic peptide (NT-BNP). Increased levels of NT-BNP correlate with increased risk of death. Other indicators like stress testing can predict a non-favourable outcome or rather - a normal test can predict a high chance for a event-free perioperative course. There is conflicting evidence of the value of preoperative echocardiography in non-symptomatic patients before non-cardiac surgery. One of the debatable issues in recent years has been whether the patient with coronary heart disease should have the non-cardiac surgery delayed and undergo coronary interventions. Acute coronary syndromes and unstable angina pectoris are high risk situations. Acute interventions are recommended in these cases or - if possible - the delay of non-cardiac surgery. However, there is scarce evidence for improved outcome with interventions in stable patients. Despite the lack of sufficient hard evidence, it seems reasonable to optimize overt heart failure and optimize medical treatment of ischaemic heart disease before non-cardiac surgery. Intraoperative anaesthetic management From the early 1980s there has been a growing understanding that good surgery and well performed anaesthesiological care is of utmost importance. The anaesthesiological team should strive for stable haemo¬dynamics and especially the avoidance of tachycardia (Slogoff & Keats 1986). The choice of a specific anaesthetic agent has been considered to be of little importance as long as the vital functions are adequately supported. The observations from cardiac surgery of improved outcome with inhalational anaesthetics are interesting (de Hert et al). However, cardiac surgery has specific features which are different from non-cardiac surgery e.g. the intended induction of myocardial ischaemia during aortic cross clamp. Thus, at present there is no substantiation of a claim that these drugs should be favoured in non-cardiac surgery. The anaesthesiologist should use the drugs and techniques in a way that keeps the haemodynamics stable during the whole perioperative period. Such measures include taking care of speed of injections of drugs, dosage of drugs in relation to the state and age of the patient, timing of adequate anaesthetic depth when stressors like intubation and start of surgery are introduced. Adequate ventilation and oxygenation cannot be overrated.