![]() ![]() It is recognised that patients who are less physically fit are more likely to experience adverse perioperative outcomes. Measuring VO 2 is of particular interest during exercise because it reflects the needs of the body in a stressed, perioperative state. During strenuous exercise, this can increase by more than 10 to 20 times, requiring a large cardiopulmonary response to deliver the required O 2 to the muscles (see Figure 2). O 2, illustrated here where trendlines cross.Īt rest, VO 2 is approximately 3.5 mL kg -1min -1. Anaerobic metabolism then further increases CO 2 production without any further utilisation of VCO2 increase linearly with increasing work rate. VO2 increases on light exercise such as slow walking, as does VCO2, proportionally. ( VCO2) of varying fraction depending on diet. Normal response to exercise: at rest, our oxygen consumption ( VO2) is approximately 250 mL min 1 with a lower CO2 production A widely accepted definition of the Fick principle states, ‘The total uptake or release of a substance by peripheral tissues is equal to the product of the blood flow to the peripheral tissues and the arterio-venous concentration difference of the substance’ 1.įigure 2. It is,however, useful to revise the Fick equation to understand how O 2 consumption ( VO 2) can be calculated from CPET measurements. ![]() ![]() An in-depth review of physiological response to exercise is not provided in this tutorial. We will examine key CPET variables, explore common patterns of physiological deviation by exercise-limiting pathology and then explain how touse these results to plan the perioperative journey. CPET goes further to quantify the degree and nature of physiological deficit based on the pattern of deviation from the norm within CPET data. Questioning a patient regarding their exercise tolerance is part of a routinepreoperative assessment and provides an indication of a patient’s comorbidity and frailty. Cardiopulmonary exercise tolerance testing (CPET) is a dynamic, noninvasive assessment of the cardiopulmonary system at rest and during exercise, performed preoperatively to determine functional capacity. ![]()
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