Evidence-based perioperative risk reduction

Abstract

HE purpose of this article is to examine the perioperative cardiac risk evidence and comment on the recommendations stemming from the evidence. We will assess the effect the evidence and the recommendations have had on practice.T Th he e d di il le em ma a Have the changes made to perioperative practice modified outcomes?Death is four times more common on the first day after surgery than the death rate in an age and risk adjusted population not having surgery.1 More than 50% of these deaths are a direct result of cardiovascular insult. The hospital costs for a postoperative cardiac related death double.2 The costs of a postoperative myocardial infarction (MI) are 50% higher than uncomplicated surgery. Furthermore, patients who survive a postoperative MI, are twice as likely to die in the next two years as patients having uncomplicated surgery. 3 The last decade has seen the introduction of preoperative assessment strategies, the America College of Cardiology and the American Heart Association (ACC/AHA) guidelines, new drugs, and minimally invasive surgical techniques. With these "improvements" there is no evidence that we have been able to alter postoperative mortality rates.Are we doing something wrong?T Th he e p pe er ri io op pe er ra at ti iv ve e a as ss se es ss sm me en nt t We undertake risk stratification in the hope that by doing so we can institute therapy that will favourably alter outcome. This implies that the strategies are accurate, and once identifying a high-risk patient, that there are effective modes to reduce risk. Is the preoperative assessment accurate?The delineation of risk begins with a good history and physical examination. There are several preoperative assessment strategies published. These strategies are not widely employed in clinical practice, most being too cumbersome or hard to remember. Table I compares three of the available risk indices. The revised cardiac risk index (RCRI) 4 is the most accurate and the easiest to remember. The RCRI has now been employed in several clinical trails to stratify for risk. We need to adopt the RCRI more widely.The risk indices perform best when coupled with the results of preoperative cardiac testing. The easiest test is a routine electrocardiogram (EKG). The finding of any abnormality in high-risk patients triples the perioperative risk. A normal EKG in a low risk patient has little discrimination. A 2D echocardiograph can be used in many ways to discriminate risk. The full potential of resting 2D echocardiogram has not been exploited at present. There is good evidence that estimation of ventricular function delineates risk.5-7 The finding of mitral regurgitation has also been linked to poor cardiac outcomes.6 Finally, the demonstration of aortic stenosis has been shown to increase perioperative cardiac risk. 8The ACC/AHA guidelines suggest that the best test, for preoperative cardiac risk stratification, is an exercise EKG. However, the demonstration of ST depression in women is not as sensitive or specific as it is in men, 30% of patients h...

Factores fisiopatológicos y metas terapéuticas perioperatorias que influyen en procedimientos quirúrgicos reconstructivos mediante colgajos en pacientes con Diabetes Mellitus

“…Es recomendable suspender la metformina uno a dos días previos a la cirugía, especialmente en pacientes en diabéticos tipo 2 o con riesgo de hipoperfusión renal, hipoxia tisular y acumulación de lactato . Esta medida busca evitar la hipoglucemia reactiva dado que los pacientes que sufren de hipoglucemia tienen una mayor duración de la estancia y un aumento en la incidencia de complicaciones, especialmente la causada por hipoglicemiantes de tipo sulfonilureas 29,[37][38][39] . Si se presentan picos de hiperglucemia, estos se deben tratar con insulina de acción rápida por vía subcutánea 25,31 .…”

Perioperative Blood Glucose Monitoring in the General Surgical Population

“…13,21,22 Sulfonylureas have a potassium-channel-blocking effect that may interfere with myocardial ischemia preconditioning. 23,24 It has been shown that patients who are undergoing coronary infusions may provide better control and are likely to be more accepted by nursing staff. 6,13,33,34 Not only have studies shown that hypoglycemia or hyperglycemia may be detrimental, but increased BG variability may also play an important role with respect to complications and outcome.…”

The diabetic surgical patient

“…The perioperative use of β blockers has been advocated for patients at increased cardiac risk [51][52][53][54]. Nonetheless, the rationale for use of β blockers in diabetics before major noncardiac surgery was recently questioned in the Diabetic Postoperative Mortality and Morbidity (DIPOM) trial [55].…”