Noninvasive determinations of the anaerobic threshold. Reliability and validity in patients with COPD

Division of Pulmonary Medicine, Cedars-Sinai Medical Center, Los Angeles.
Chest (Impact Factor: 7.48). 10/1992; 102(4):1028-34. DOI: 10.1378/chest.102.4.1028
Source: PubMed


We compared the intraobserver and interobserver agreement of blood (BGT) and gas exchange (GET) methods for determination of the anaerobic threshold (AT) in patients with COPD. In addition, we determined the sensitivity and specificity of the gas exchange methods for determination of the AT. Two noninvasive methods, the V-slope (VS) and the ventilatory equivalents method (VEM) were compared with two blood sampling methods, the log standard HCO3 (SB) vs log VO2 (SBT) and base excess (BE) vs VO2 (BET). Twenty-nine patients with COPD (FEV1 < 60%) performed incremental exercise tests to exhaustion while breath-by-breath gas exchange measurements were made. Blood samples were drawn at the end of each minute for SB and BE. Two trained observers determined the VO2 at the threshold for each of the four indices on two separate occasions two weeks apart. Our results demonstrated the following: only modest interobserver and intraobserver agreement was noted by Spearman rank correlations; the VEM was as sensitive as the VS in COPD patients; and the presence of a true metabolic acidosis was not reliably predicted by GET methods. Moreover, although the blood methods accurately identified the presence of metabolic acidosis, there was disagreement on the actual point of the BGT. We conclude that gas exchange indices were not helpful for the determination of metabolic acidosis in patients with COPD.

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    • "Absence of the AT in COPD patients can indicate that exercise was terminated before significant metabolic acidosis occurred. In addition , gas exchange methods for the determination of the AT in COPD patients do not agree with the methods that are based on the assessment of anaerobic metabolism in venous blood (Belman et al., 1992). The ventilatory limitation of advanced COPD is also reflected in the development of hypercapnia at rest and during exercise with marked ventilation to perfusion abnormalities, which can be significantly worsened due to dynamic hyperinflation (Dempsey, 2002; O'Donnell et al., 2002). "
    [Show abstract] [Hide abstract] ABSTRACT: Impaired ventilation on cardiopulmonary exercise test (CPET) is seen in patients with chronic obstructive pulmonary disease (COPD). However, evaluation of the differences of abnormal gas exchange in COPD according to GOLD severity criteria is limited. A retrospective review was performed on all COPD patients referred for CPET at our center between 1998 and 2010. There were 548 patients compared according to GOLD severity. GOLD groups were significantly different from each other in regards to pressure of end-tidal carbon dioxide ( [Formula: see text] ) with progressively higher [Formula: see text] with increasing GOLD severity. Ratio of minute ventilation to carbon dioxide production ( [Formula: see text] ) and exercise capacity as measured by and [Formula: see text] % and work rate in watts% was inversely proportional to GOLD severity. Breathing reserve, minute ventilation, and tidal volume at peak exercise were significantly decreased with increasing disease severity between GOLD groups. We concluded that gas exchange is distinctive among different GOLD severity groups; specifically, GOLD 3 and 4 have a significantly higher [Formula: see text] and a significantly lower [Formula: see text] than GOLD 2.
    Full-text · Article · Jan 2013 · Respiratory Physiology & Neurobiology
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    • "The VT and GET are widely used in CF patients [5] [6]. Unfortunately, it is well known that these thresholds cannot be always determined in patients with chronic airflow limitation [5] [7] and are dependent on numerous factors, including the characteristics of the protocol, the method of detection, and the intra or inter observer variability [8] [9]. "
    [Show abstract] [Hide abstract] ABSTRACT: The present study investigated the validity and the reliability of the oxygen uptake efficiency slope (OUES) as a determinant of exercise tolerance in adults with cystic fibrosis (CF). 31 CF patients and 34 healthy controls performed a maximal incremental cycle test with respiratory gas-exchange measurements. OUES was calculated from data taken from different percentages of the entire exercise duration, including 80% (OUES(80)) and 100% (OUES(100)). Peak oxygen uptake (VO(2peak)) and gas exchange threshold (GET) were also determined. The agreement between submaximal parameters and VO(2peak) was assessed using Bland Altman plots. Test retest reliability was evaluated in CF patients using absolute (SEM) and relative indices (ICC). On the contrary to the GET, which was undetectable in 16% of the CF patients, the OUES was easily determined in all patients. Among all the submaximal variables, OUES(80) had the best reliability (ICC=0.94, SEM=7.3%) and agreement with VO(2peak) (r(2)=0.83, P<0.01; limits of agreement: ±365mL min(-1)) and did not differ from OUES(100). OUES(80) is a reliable and more useful submaximal parameter than the GET and may find use in the interpretation of exercise studies in CF patients who are unable to perform maximal exercise.
    Full-text · Article · Mar 2010 · Journal of cystic fibrosis: official journal of the European Cystic Fibrosis Society
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    [Show abstract] [Hide abstract] ABSTRACT: Sporadic visits to the local doctor followed sometimes by changes in oral and inhaled bronchodilators and occasionally by the addition of steroids frequently does little to significantly improve symptoms and function in the disabled patient with COPD. As in other chronic diseases, the management of these patients is facilitated by a team approach in conjunction with general rehabilitation principles. The rationale and practical implementation of such a programme has recently been outlined by the American Association of Cardiopulmonary Rehabilitation. These are multifaceted programmes but a key component, as outlined above, is exercise training. In this brief review the various approaches available have been described. Controversy still reigns regarding the optimal modes of training and there are important differences among the several approaches. Two main groups can be delineated. One emphasises the detailed definition of the impaired physiology with therapeutic measures targeted to specific defects. There is good documentation that, conversely, unstructured programmes that use treadmill and free range walking and cycling also improve endurance for walking. Upper extremity training is of additional benefit. Programmes with as little as three sessions per week of 1-2 hours of low intensity activity have achieved success so we know that simple programmes can be helpful. Moreover, without the necessity for complex testing and training methods these programmes can be implemented with relatively low costs. Future investigations to examine the relationship between improved exercise capacity for walking and arm exercise on the one hand, and the ease of performance of activities of daily living on the other, will help to reinforce the effectiveness of exercise programmes.
    Preview · Article · Oct 1993 · Thorax
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