Preoperative cardiopulmonary exercise testing

Editor—We were interested to read the article by Murrayand colleagues¹ which demonstrated the value of a shuttle walktest in predicting outcome after oesophagectomy. It would appearthat an inability     

Treadmill exercise testing with increasing inclination as exercise protocol for wheelchair athletes.

STUDY DESIGN: Treadmill testing on a progressive incline of 11 wheelchair athletes. OBJECTIVE: To determine if a novel treadmill exercise protocol which uses increments in inclination, rather than the standard increments in velocity, can be used to effectively determine maximum oxygen uptake VO2max for elite wheelchair athletes. SETTING: Nottwil, Switzerland. METHODS: Eleven elite wheelchair basketball players (29.3+/-6.3 years, 72.7+/-16.9 kg and 177+/-9.6 cm) performed an exercise protocol with increasing inclination on the treadmill. Eight players had a spinal cord injury (SCI), two had no lesion of the central nervous system and one had poliomyelitis. VO2max and heart rate were measured continuously, while serum lactate was determined immediately after the exercise protocol. RESULTS: Athletes reached a maximal heart rate of 185+/-11.4 bpm and maximal lactate of 10.2+/-2.1 mmol/l. VO2max was 35.1+/-4.9 ml/min/kg. The correlation between heart rate and VO(2) at different inclinations was statistically significant and comparable to able-bodied subjects. CONCLUSIONS: An exercise protocol with increasing inclination is a valid alternative to an exercise protocol with increasing velocity.     

Quality control,quality assurance,and proficiency testing in the andrology laboratory

The primary goal of any andrology laboratory should be the performance of accurate, reproducible, high-quality, and clinically relevant laboratory testing. An underlining objective of such a goal is to better serve the ordering physician, and the patient, by continually improving laboratory performance. Quality control (QC) is the procedure that determines accurate and reproducible testing. Proficiency testing (PT) is the process allowing physicians to compare results from one laboratory to another. Quality assurance (QA) is the mechanism ensuring high-quality, clinically relevant testing. Together, QC, QA, and PT serve as the foundation responsible for a program that continually improves the overall quality of the testing, allowing the physician ordering the test to be more effective in treating the patient. Several examples are presented to assist the implementation of effective QC and QA programs aimed at continually improving performance in the andrology laboratory.     

Physiological basis of preoperative cardiopulmonary exercise testing

The use of cardiopulmonary exercise testing (CPET) is gaining popularity as a preoperative functional assessment tool and a useful adjunct to risk stratification before surgery. Determination of the integrated response of multiple body systems (including the cardiorespiratory and peripheral oxygen delivery systems) to exercise stress, adds important prognostic value to pre-surgical assessment, shared-decision making and postoperative management of the surgical patient. Thorough CPET interpretation is complex but may be assisted by an understanding of basic exercise physiology and its application to the preoperative context.     

Physiological basis of preoperative cardiopulmonary exercise testing

The use of cardiopulmonary exercise testing (CPET) is gaining popularity as a preoperative functional assessment tool and is a useful adjunct to risk stratification before surgery. Determination of the integrated response of multiple body systems (including the cardiorespiratory and peripheral oxygen delivery systems) to exercise stress, adds important prognostic value to pre-surgical assessment, shared-decision making and post-operative management of the surgical patient. Thorough CPET interpretation is complex but may be assisted by an understanding of basic exercise physiology and its application to the preoperative context.     

Perioperative cardiopulmonary exercise testing in the elderly

The elderly constitute an increasingly large segment of the population and of the patients requiring medical attention. Major surgery is associated with a substantial burden of postoperative morbidity and mortality. Advancing age is a particular risk factor for these outcomes. This article reviews the current literature on the value and practical applications of cardiopulmonary exercise testing (CPET) as a tool to evaluate risk and thereby improve the management of the elderly patient undergoing major surgery. There is a consistent association between CPET-derived variables and outcome following major surgery. Furthermore, CPET-derived variables have utility in perioperative risk prediction and identification of patients at high risk of adverse outcome following major surgery. This optimal predictor appears to differ between various surgery types and the incremental benefit of combining CPET with alternative methods of perioperative risk prediction remains poorly defined.     

Cardiopulmonary exercise testing in the preoperative assessment for lung resection surgery

Whereas pulmonary function tests (PFTs) initially identify high-risk pulmonary patients being evaluated for lung resection surgery, other diagnostic modalities, including cardiopulmonary exercise testing (CPET) and/or split function studies, are then necessary for a more accurate assessment. CPET including VO2max have emerged as integral components of a step approach for the physiologic assessment for lung resection surgery. Increasingly, CPET is being used because it provides the best index of functional capacity and global O2 transport (VO2max) as well as estimating both cardiac and pulmonary reserves not available from other modalities. CPET permits the detection of clinically occult heart disease and provides a more reliable estimate of functional capacity postoperatively compared with PFTs, which routinely overestimate functional loss after lung resection. Currently, though split function studies are clearly established and have traditionally been used before CPET in preoperative decision analysis, recent work favors using CPET including VO2max before split function studies because VO2max % predicted is a good independent predictor of risk. Importantly, both studies are complementary and optimize assessment of surgical risk; this is particularly valuable for borderline patients, so that opportunity for curative resection is not denied.     

Diagnosis of pulmonary vascular limit to exercise by cardiopulmonary exercise testing.

BACKGROUND: Given the recent development of newer and less-invasive treatments for pulmonary hypertension, and the long wait for lung transplantation, early and correct diagnosis of this condition is increasingly important. The purpose of this study was to determine and improve the accuracy of a non-invasive, cardiopulmonary exercise-testing algorithm for detecting a pulmonary vascular limit to exercise. METHODS: We performed 130 consecutive, incremental cycling-exercise tests for exertional symptoms with pulmonary and radial artery catheters in place. Pulmonary vascular limit was defined as pulmonary vascular resistance at maximum exercise >120 dynes. sec/cm(5) and a peak-exercise systemic oxygen delivery <80% predicted, without a pulmonary mechanical limit or poor effort. We applied a previously reported non-invasive exercise-test-interpretation algorithm to each patient and sequentially manipulated branch point threshold values to maximize accuracy. RESULTS: The sensitivity of the original non-invasive algorithm for pulmonary vascular limit was 79%, specificity was 75%, and accuracy was 76%. Sensitivity did not change with systematic alteration of branch-point threshold values, but specificity and accuracy improved to 88% and 85%, respectively. Accuracy improved most by modifying the threshold values for percent predicted maximum oxygen uptake and carbon dioxide output ventilatory equivalents at lactate threshold. CONCLUSION: Non-invasive cardiopulmonary exercise testing is a useful tool for detecting and excluding a pulmonary vascular limit and for determining whether abnormal pulmonary hemodynamics limit aerobic capacity.     

Automated impedance cardiography for detecting ischemic left ventricular dysfunction during exercise testing

Automated impedance cardiography (ICG) is an attractive method for noninvasive hemodynamic evaluation. The objective of our study was to evaluate the feasibility and diagnostic value automated ICG in patients with suspected coronary artery disease (CAD). We measured stroke index (SI) and cardiac index (CI) in 65 patients with suspected CAD at rest and during bicycle exercise testing. All patients underwent subsequent cardiac catheterization including coronary angiography (CA). Depending on the results of CA, patients were divided into three groups, patients without significant CAD (group 0), single vessel disease (group 1) or multivessel disease (group 2-3). In a subset of 20 patients, automated ICG was compared to measurements of CI by the thermodilution (TD) method. Results: There were no significant differences in SI and CI at baseline between the three groups. At 75- and 100-watt exercise, patients in group 2-3 showed significantly lower mean values of SI and CI as compared to patients of group 0 and group 1 (all p < 0.05), indicating exercise-induced ischaemic left ventricular (LV) dysfunction. Three patients had to be excluded because of inappropriate quality of the ICG signals during exercise. Comparison of automated ICG with TD measurements of CI showed good correlations between both methods at rest (r = 0.73) and during exercise (r = 0.89-0.91). Conclusions: We conclude that hemodynamic monitoring by automated ICG is both feasible and practical during exercise testing. Automated ICG can provide reliable and valuable additional diagnostic information on LV function during exercise which is helpful for selecting those patients for angiography who are likely to benefit from coronary interventions.