الفهرس 
Preoperative Assessment of Cardiac Patients in Noncardiac SurgeryOnly 14 pages are availabe for public view
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Abstract
Preoperative evaluation must embrace more than just risk factor analysis for ischaemic heart disease (IHD), it should involve detection of all cardiac disease and most importantly, objective assessment of functional capacity. Exercise tolerance is a major determinant of perioperative risk. It is usually evaluated by the estimated energy requirement for various activities and graded in metabolic equivalents (MET). One MET represents the oxygen consumption of a resting adult (3.5 mL/kg/min). More simply, the inability to climb two flights of stairs is associated with a positive predictive value of 89% for cardiopulmonary complications.
Cardiopulmonary exercise test (CPET) is the most reliable and objective test for evaluation of functional capacity. It allow for the analysis of gas exchange at rest, during exercise and during recovery and yield breath-by-breath measures of oxygen uptake (V̇o2), carbon dioxide output (V̇co2), and ventilation V̇e Because most activities of daily living do not require maximal effort, a widely used submaximal index of exercise capacity is the anaerobic or ventilatory threshold (VT). Comprehensive CPET is useful in a wide spectrum of clinical settings. Its impact can be appreciated in all phases of clinical decision making including diagnosis, assessment of severity, disease progression, prognosis, and response to treatment.
The diagnosis of postoperative cardiac failure should be made before progression to cardiac morbidity or to organ failure. Ideally, preoperative identification of patients at risk of this problem will result in modification of postoperative management, i.e. triage to monitored care in an intensive care unit (ICU), before the patients at risk identify themselves by exhibiting the postoperative morbididty. So, modification of perioperative management for such patient, including elective ICU admission and use of haemodynamic monitoring, dramatically lowers morbidity and results in lower mortality and improved resource utilization. Patients with an AT < 11 mL/min/kg were considered “high risk” and were admitted to the ICU preoperatively. Those patients with an AT > 11 mL/min/kg but with either myocardial ischemia (demonstrated during the CPX test) or a V̇e / V̇o2 of > 35 were admitted to the HDU postoperatively. Those patients with an AT > 11 mL/min/kg, but with no myocardial ishcemia or a V̇e/(V̇o2), of <35, were sent to the general ward after surgery