Provider group characteristics & quality report card performance: a cross-sectional study in a managed care setting.

We describe 1 health plan's annual, incentive-based, provider group quality report card (Scorecard) and identify trends in Scorecard performance among 142 California provider groups. We explore variation in Scorecard performance by provider group characteristics. Scorecard evaluates provider groups on standardized measures of performance including preventive screening, patient satisfaction, and quality management operations and infrastructure. In a cross-sectional study, we use linear regression to measure associations between provider group characteristics and performance on the 1997 Scorecard. Provider group performance trends (1996-1997) revealed improvement on 6 Scorecard indicators. Regional differences in performance were also shown. Multivariate results indicate that group location in northern California (P = .01), IPA (independent practice association) status (P = .02), older group age (P = .02), and higher mean patient age (P < .01) were independently associated with higher 1997 Scorecard total scores. Member education was marginally associated with performance. Group size, member income, and gender distributions were not independently associated with Scorecard performance. Results of this study suggest that (among Blue Cross of California's contracted provider groups) older, more established groups; groups located in northern California; IPAs; and groups with a patient demographic mix characterized by higher than network average mean age and a lower than network average proportion of members with a college education or greater were more likely to perform well on Scorecard.

Using a quality scorecard to measure and improve medical groups' performance.

BACKGROUND: Blue Cross of California (BCC) uses an annual Quality Scorecard to measure performance of participating medical groups (PMGs) and independent practice associations (IPAs). The scorecard provides information to the PMGs/IPAs on their performance in several domains relative to the average network score. BCC pays annual bonuses to PMGs/IPAs with superior quality performance. A structured intervention was designed to improve the performance of PMGs/IPAs that performed poorly on the scorecard. METHODS: A cohort study was conducted in a large health maintenance organization in California in 1997. All PMGs/IPAs received a detailed summary of the components of the annual quality scorecard. Scorecard components include an annual audit of quality, utilization management, credentialing, and members' rights and responsibilities, grievance rates, member transfer for quality reasons, a satisfaction survey, and a preventive health review. Twenty-two of 124 PMGs/IPAs with more than 1,000 BCC members during 1996 that had scored lower than 1 standard deviation below the mean were targeted. These 22 outlier PMGs/IPAs received additional information indicating that their performance was below average. A BCC quality team subsequently visited the outlier PMGs/IPAs to provide supplementary information on the deficient areas and provide assistance in making improvements. RESULTS: The outlier groups showed significant improvements in the annual audit of quality score, member satisfaction with access, member satisfaction with last visit, overall member satisfaction with PMGs/IPAs, mammography screening, and the total score. CONCLUSIONS: A structured quality improvement intervention in poorly performing PMGs/IPAs was followed by improvements in specific performance measures.

Risk and protective factors associated with screening for complications of diabetes in a health maintenance organization setting.

OBJECTIVE: To identify risk and protective factors associated with screening for complications of diabetes, we performed a cross-sectional study of 3,612 diabetic members enrolled in CaliforniaCare, a large network-model health maintenance organization (HMO). RESEARCH DESIGN AND METHODS: We used the Health Plan and Employer Data Information Set (HEDIS) 3.0 technical definition to identify all members (aged > or = 31 years) receiving any diabetes medication(s) during a 12-month period. Using a telephone survey instrument, identified members were interviewed about their diabetes care and screening, patient, and provider history. Survey data were supplemented with HMO claims and demographic information. Multivariate analysis was performed to identify demographic, clinical, and utilization characteristics that affect the odds of diabetic members receiving annual retinal examination, foot examination, and HbA1c testing. RESULTS: While results varied by screening category, the odds of obtaining screening were higher for diabetic members who were older, spoke English, received diabetes nutrition counseling, visited a diabetes specialist physician, belonged to a diabetes association or support group, used insulin, performed glycemic level self-examination at least once a day, and had higher overall prescription drug use (suggesting higher comorbidity). Since this study is a cross-sectional review, these results do not imply a cause-and-effect relationship between dependent and independent variables. CONCLUSIONS: Results of this study suggest barriers, risks, and protective factors associated with screening for complications of diabetes. Diabetic members who do not possess these characteristics may be at increased risk.

Reducing length of stay for patients hospitalized with exacerbation of COPD by using a practice guideline.

UNLABELLED: Clinical practice guidelines have been promoted as an effective way of reducing costs while maintaining quality care. OBJECTIVE: To study a practice guideline to shorten length of stay for patients hospitalized with exacerbation of COPD. METHODS: We retrospectively studied a practice guideline to identify patients who were at low risk of complications from their exacerbation of COPD and hence potentially suitable for early hospital discharge. We then prospectively studied the practice guideline using an alternate month intervention and control time series over a period of 12 months. RESULTS: The practice guideline was retrospectively studied in 250 consecutive patients hospitalized with exacerbation of COPD. Of the 250 patients, 237 patients (94.8%) were classified as low risk after 72 h of hospitalization and were potentially suitable for discharge. In the prospective study, few patients (24 of 124 or 19%) were identified for implementation of the guideline. However, in those patients who were identified, length of stay was not statistically different. The data also showed that length of stay for both intervention and control groups had shortened over this time. CONCLUSION: Certain practice guidelines may appear efficacious in studies but may actually lack effectiveness when applied in clinical settings and may even increase costs. We demonstrated the importance of prospectively evaluating clinical practice guidelines before recommending them for widespread implementation.

Evaluation of a pneumonia practice guideline in an interventional trial.

There are few available data to define the medically necessary duration of stay for patients hospitalized with pneumonia. Therefore, we investigated the safety and effectiveness of a practice guideline that provided information about switching patients from parenteral to oral antimicrobials and early hospital discharge. The study was a prospective controlled study with an alternate month design. The practice guideline was studied in 146 "low-risk" pneumonia patients hospitalized during a 22-month period. Medical care consistent with the practice guideline occurred in 64% and 76% of patients during control and intervention periods, respectively (p=0.15). There were no differences in patient outcomes in the control and intervention groups when measured 1 mo after hospital discharge, including hospital readmission rates, health-related quality of life, and patient satisfaction. Explicit and implicit review revealed that 98.6% (95% confidence interval [CI]: 95.1%, 99.8%) of low-risk patients would not have benefited from continued hospitalization after the fourth hospital day. The 30-d survival rate of the low-risk pneumonia patients was 99.3% (95% CI: 96.2%, 100%) and patient outcomes appeared to be favorable compared with previously published values. We conclude that duration of hospital stay was frequently consistent with the practice guideline in both study groups, and patient outcomes remained unchanged. The guideline will require additional testing before it can be recommended for use.

Inhaled bronchodilators reduce dynamic hyperinflation during exercise in patients with chronic obstructive pulmonary disease.

Dynamic hyperinflation (DH) is a major pathophysiologic consequence of airflow limitation during exercise in patients with chronic obstructive pulmonary disease (COPD) and an important contributing factor to breathlessness. In this study we aimed to examine the effect of inhaled beta agonist therapy on DH during exercise in these patients and the relationship between changes in DH and breathlessness. In 13 COPD patients (mean age 65.1 +/- 2.0, FEV1 1.20 +/- 0.17, FEV1/FVC 40 +/- 3) we measured pulmonary function tests, exercise breathlessness by Borg score, and exercise flow volume and pressure volume loops on two separate days. Prior to testing, patients randomly received inhaled placebo or albuterol on the first test day and the alternative medication on the second test day. From measurements of exercise inspiratory capacity (IC), we calculated the end-expiratory and end-inspiratory lung volumes (EELV, EILV). We used esophageal pressure recordings to measure peak inspiratory esophageal pressure (Pesins) during exercise and this was related to the maximal capacity for pressure generation taking into account lung volume and airflow changes (Pcapi). Bronchodilator caused significant increase in both FEV1 and FVC (+0.23 and +0.51, p<0.01). Comparisons of breathlessness, exercise volumes, and pressures were made at the highest equivalent work load. There was a significant reduction in the peak exercise EELV/TLC (80 +/- 0.02% to 76 +/- 0.02%, p<0.05) while the peak EILV/TLC decreased by 2% (97 +/- 1% to 95 +/- 1%, p<0.05). The peak Pesins/Pcapi decreased (0.79 +/- 0.10 to 0.57 +/- 0.05, p<0.05), and the Pcapi - Pesins increased (7.4 +/- 3 to 13.0 +/- 3 cm H2O, p<0.05). There was significant improvement in neuroventilatory coupling for volume change (Pesins/Pcapi/VT/TLC 5.45 +/- 0.5 to 3.25 +/- 1.0, p<0.05). There was a significant reduction in breathlessness as measured by Borg score (4.5 +/- 0.7 to 3.1 +/- 0.5, p<0.05) and there was a significant correlation between delta Borg and delta EILV/TLC (r=0.771, p<0.01) with a trend for Pesins/Pcapi/VT/TLC (r=0.544, p=0.067). There was also a significant correlation between delta EELV/TLC and delta Pesins/Pcapi/VT/TLC (r=0.772, p<0.01). The relationships between delta Borg, delta resting volumes, and flow rates were not significant. We conclude that in patients with COPD, inhaled bronchodilator reduces exercise DH and improves inspiratory pressure reserve and neuroventilatory coupling. Changes in DH and neuroventilatory coupling were the main determinants of reduced breathlessness.

Bronchiolitis obliterans in single-lung transplant recipients.

The presentation and clinical course of bronchiolitis obliterans (BO) in single-lung transplant (SLT) recipients has thus far not been well described. We retrospectively analyzed the serial spirometry of 15 SLT patients with BO. All the patients fulfilled the criteria for BO syndrome, and 11 of the 15 had histologically documented BO. Based on serial FEV1 analysis, we identified three patterns of presentation and progression of BO. The first pattern (n = 6) was characterized by a rapid onset and a relentless progressive course; the second pattern (n = 5) was characterized by a similar rapid onset and initial rapid decline, but was followed by stabilization in lung function; the third pattern (n = 4) was characterized by an insidious onset and course. In all patients, a permanent reduction in the mean forced expiratory flow during the middle half of the forced vital capacity appeared to be an early sensitive index for the development of BO. An appreciation of these different modes of presentation and progression of BO is potentially important in the assessment of prognosis and management of the SLT recipient.

Work of breathing after extubation.

Recently we showed that work of breathing was higher in the immediate period after extubation as compared with spontaneous breathing through an endotracheal tube. In this study, we evaluated the glottis and trachea as potential sites of increased airway resistance after extubation. We measured breathing pattern, work of breathing, and pressure time product in eight patients during weaning from mechanical ventilation. We acquired data during pressure support ventilation and spontaneous breathing via the ventilator, with the endotracheal tube in place, and after extubation. During bronchoscopy at the time of extubation, we examined the trachea and measured the cross-sectional area of the glottis. Work of breathing and pressure time product were significantly lower during pressure support ventilation as compared with spontaneous breathing after extubation (0.43 +/- 0.10 vs 1.49 +/- 0.10 J/L and 101 +/- 22 vs 299 +/- 30 cm H2O.s/min, respectively; p < 0.05). However, both indexes were significantly higher after extubation as compared with breathing through the endotracheal tube (1.49 +/- 0.10 vs 0.95 +/- 0.12 J/L, 299 +/- 31 vs 196 +/- 26 cm H2O.s/min respectively; p < 0.05). During bronchoscopy, no tracheal or glottic narrowing was detected. The glottic cross-sectional area was successfully measured in four patients at the onset of inspiration and found to be 140 +/- 15 mm2. This value was larger than the mean cross-sectional area of the endotracheal tubes used in these patients (50 mm2). We conclude that neither tracheal nor laryngeal disease caused the increase in work of breathing after extubation. Our data suggest that upper airway narrowing at a more proximal site, such as the oropharynx or velopharynx may be the cause of the increase in respiratory work.

Characteristics of the ventilatory load with different ventilatory training devices.

BACKGROUND: The characteristics of the load on the ventilatory muscles during breathing with different ventilatory muscle training devices have not been quantified, which may profoundly affect the nature of the training stimulus and the clinical outcome of the ventilatory muscle training. METHODS: In four normal males, we continuously measured mouth pressure, esophageal pressure, tidal volume, breathing frequency (fb), minute ventilation (VE), inspiratory time, duty cycle, tension time index (TTI), and total respiratory work (WTOT) during 10 seconds' maximum ventilatory maneuvers. Maximum breathing was performed at 3 fb's (20, 60 and 88 breaths/min) with each of 3 different inspiratory loading devices: 1) Isocapnic hyperpnea (H) with an orifice of 2 (H2) and 1 (H1) cm; 2) Resistive breathing through a Pflex using 3 orifices of diameter 0.54 cm (P1), 0.40 cm (P3) and 0.22 cm (P5); 3) A threshold loading device (T) set at 10 (T10) and 25% (T25) of the previously measured maximum inspiratory mouth pressure. RESULTS: Pflex could provide higher TTI and lower VE, compared with the other 2 devices, at the breathing frequencies of 60 and 88 breaths/min (p < 0.05). Pflex with smaller orifices (P3 and P5) could exaggerate this difference (p < 0.01). WTOT increased significantly as fb increased from 20 to 88 with H1, H2, T10, T25 and P1 (p < 0.02), but not with P3 and P5. VE showed a better correlation with WTOT than TTI did (p < 0.001, r = 0.863 vs p > 0.1, r = -0.365). CONCLUSIONS: High flow, high WTOT and low tension loads were provided by H2, H1, T10 and T25 devices whereas low flow, low WTOT and high tension loads were provided by P5 and P3. P1 provided intermediate flow and tension load.

The relationship between oxygen consumption and work rate in patients with airflow obstruction.

The oxygen cost of augmented ventilation is increased in patients with chronic obstructive pulmonary disease, either at rest or during exercise. Thus, if excessive demands are placed on the respiratory muscles during exercise in these patients, we postulate that the total oxygen consumption (VO2) may increase relative to the work rate compared to control subjects. The aim of this study was to examine the relationship between VO2 and work rate during exercise in patients with airflow obstruction. A retrospective analysis of data collected over 7 years was conducted. Patients with airflow obstruction (n = 131) were compared and contrasted with those in whom pulmonary function studies (spirometry, lung volumes) were normal (n = 199). Severity of airflow obstruction (ie, mild moderate, severe) was determined, using the 95 percent confidence limits for the ratio of FEV1 to FVC. Incremental exercise studies were performed on a cycle ergometer. Resting VO2 was not significantly different across the groups with airflow obstruction measured either directly or normalized for body weight. The VO2max was significantly reduced in the patients with severe airflow obstruction, compared with the normal group, as well as the patients with mild and moderate airflow obstruction. No differences were noted in the slope of VO2 plotted against work rate in the patients with airflow obstruction (regardless of the severity of the obstruction) and individuals in whom results of pulmonary function tests were normal. In addition, when gender was taken into account, there was essentially no difference in the slopes for either male or female subjects across all groups. Stepwise, linear regression failed to demonstrate any variable or variables that were strongly related to slope. We postulate that the maintenance of a normal slope of VO2 on work rate in patients with airflow obstruction, in whom the oxygen cost and work of breathing is likely increased, may mask a significant reduction in nonrespiratory VO2 (for example, to exercising skeletal muscles).

Obstructive flow-volume loop contours after single lung transplantation.

The development of spirometric airflow obstruction may be a diagnostic dilemma in recipients of single lung allografts. The contribution of bronchial anastomotic stenosis to the observed spirometric obstruction may be clinically difficult to distinguish from that of obliterative bronchiolitis. Similarly, differentiating the "normal" obstructive defect after single lung transplantation for emphysema from obliterative bronchiolitis may be clinically challenging. We retrospectively reviewed the maximum inspiratory and expiratory flow-volume loop contours of lung transplant recipients with either obliterative bronchiolitis (n = 7) or bronchoscopically diagnosed severe bronchial anastomotic stenosis (n = 3). Five patients underwent single lung transplantation for obstructive native lung diseases and underwent observation before and after development of obliterative bronchiolitis. Bronchial anastomotic stenosis-maximum inspiratory and expiratory flow-volume loops were analyzed both before and after correction of stenosis by niobium: yttrium-aluminum-garnet laser photoresection or endobronchial silicone stent placement. Measures of airflow derived from maximum inspiratory and expiratory flow-volume loops, such as peak expiratory flow, peak inspiratory flow, forced expiratory flow at 50% vital capacity, forced inspiratory flow at 50% vital capacity, and forced expiratory volume in 1 second/peak expiratory flow ratio could not differentiate patients with bronchial anastomotic stenosis versus obliterative bronchiolitis. The most clinically useful index was the maximum inspiratory and expiratory flow-volume contour, which was characterized by terminal plateaus during exhalation and inhalation in patients with bronchial anastomotic stenosis. This index was reflected in a lower forced inspiratory flow at 75% vital capacity and forced inspiratory flow at 75% vital capacity/peak inspiratory flow ratio in bronchial anastomotic stenosis that increased after elimination of the anastomotic obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of low-risk hospitalized patients with pneumonia. Implications for early conversion to oral antimicrobial therapy.

PURPOSE: Few available data exist to define either the medically necessary duration of parenteral antimicrobial therapy or length of stay for hospitalized patients with pneumonia. Therefore, we investigated the potential safety and effectiveness of a practice guideline recommending early conversion of low-risk patients with pneumonia from parenteral to oral antimicrobial therapy and early hospital discharge. PATIENTS AND METHODS: The practice guideline was studied retrospectively in 503 hospitalized patients with pneumonia at a teaching community hospital. RESULTS: Thirty-three percent of patients with pneumonia were classified as at low risk for complications and potentially suitable for early conversion to oral antimicrobial therapy according to the guideline. Were the guideline to have been used to guide patient discharge decisions, 619 additional bed-days would have been made available to accommodate incoming patients. A consensus among physician reviewers led to the judgment that quality of care would not have worsened for 98.2 percent of low-risk patients had they been switched to oral antimicrobial therapy on the third hospital day, nor would quality of care have been worsened for 93.4 percent of low-risk patients had they been discharged on the fourth hospital day. CONCLUSION: The practice guideline that we studied has the potential to safely reduce the duration of parenteral antimicrobial therapy and length of hospital stay for selected low-risk patients with pneumonia. The guideline should be studied in a prospective clinical trial.

Ventilatory load characteristics during ventilatory muscle training.

The response of skeletal muscle to training is influenced by both the intensity and nature of the training stimulus. In this study we investigated the characteristics of the ventilatory load applied to the ventilatory muscles during several different modes of ventilatory muscle training. Patients with chronic obstructive pulmonary disease (COPD) performed the following breathing maneuvers: (1) Unloaded hyperpnea (UH), (2) resistive breathing through a fixed orifice (0.5 cm diameter) at frequencies of 15 and 30 breaths/min (RT15, RT30), (3) loaded breathing through a threshold valve set at 30% of the PImax at frequencies of 15 and 30 breaths/min (TT15, TT30), and (4) repetitive maximal inspiratory maneuvers against a closed shutter (PImax). During these maneuvers were recorded airflow and pressures at the month and esophagus, and from these measurements we derived VE and the work of breathing (WOB), tension time index (TTI), and pressure time product (PTP). The VE during UH was significantly higher than all other modes (p < 0.01), whereas the Pesmax was significantly lower during UH than during the resistive and loaded maneuvers (p < 0.01). The WOB did not differ during UH, TT30, and RT30, but was significantly higher in all three modes than at TT15 and RT15 (p < 0.05). During RT30 the TTI was higher than during TT30, TT15, and RT15 (p < 0.05), whereas the TTI during UH was significantly lower than during other maneuvers (p < 0.01). As expected, the highest Pesmax and PTP were found during the PImax maneuver. These data show that important qualitative differences in ventilatory muscle loading can be achieved by means of different devices and breathing strategies.(ABSTRACT TRUNCATED AT 250 WORDS)

Prediction of maximal exercise capacity in obstructive and restrictive pulmonary disease.

We evaluated the predictive value of resting pulmonary function tests (PFTs) in the determination of maximal exercise capacity in patients with obstructive and restrictive ventilatory disease. We performed resting PFTs and an incremental exercise study on a bicycle ergometer in 146 patients with chronic obstructive pulmonary disease (COPD) and 68 patients with restrictive disease. The patients with obstructive disease were further subdivided into mild, moderate, and severe based on the severity of their airway obstruction (mean +/- SD:FEV1, 2.78 +/- 0.77, 2.12 +/- 0.74, and 1.06 +/- 0.47, respectively). Correlation coefficients for PFTs vs VO2max and VEmax in restricted patients was generally low (DL = 0.67 and 0.34, IC = 0.58 and 0.35, FVC = 0.57 and 0.35, TLC = 0.35 and 0.18). In patients with COPD, the maximum voluntary ventilation (MVV) was the single best predictor of VO2 in all groups with correlation coefficients of 0.75, 0.69, and 0.89 in the mild, moderate, and severe subgroups, respectively. Similarly, the MVV was the best predictor of VEmax in all groups with correlation coefficients of 0.59, 0.64, and 0.89 in the three subgroups. The correlation with FEV1 was slightly less for both VO2max (0.69, 0.65, and 0.87) and VEmax (0.52, 0.64, 0.64) in the mild, moderate, and severe subgroups, respectively. Our findings show that PFTs are unreliable in predicting VEmax and VO2max in restricted patients. In patients with obstruction, the MVV is the single best predictor of VO2max and VEmax in all three categories, but was not significantly improved by stepwise multiple regression with additional PFT variables. Higher correlations were obtained in the severe group in whom the correlation with VO2max and VEmax was 0.89. However, the 95 percent confidence interval of the estimate for VO2 and VE was relatively large (+/- 0.16 L/min and +/- 6.6 L/min, respectively). We conclude that although several PFTs correlate significantly with maximum exercise, the large variance precludes their use to accurately predict maximum performance in individual patients with COPD.

Exercise in patients with chronic obstructive pulmonary disease.

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.

Prediction of minimal pressure support during weaning from mechanical ventilation.

Our goal was to evaluate the accuracy of a prediction equation that estimates the minimal level of pressure support (PS) required to overcome the resistance of the ventilator circuit and the endotracheal tube during mechanical ventilation. We calculated the minimal PS (PSmin) by means of the relationship between airway resistance and peak inspiratory flow rate during mechanical ventilation. Measurements of breathing pattern, flow rates, work of breathing (WOB), pressure time product (PTP), and PEEPi were made during several modes of ventilation (PSmin, PSmin + 25 percent, PSmin-25 percent, flow by, CPAP 0 cm H2O) and while breathing through an endotracheal tube (ETT) and spontaneous breathing (EXT). The WOB was significantly higher during EXT than PSmin, PSmin-25 percent, and ETT (1.04 vs 0.45, 0.54, and 0.74 J/L, respectively, p < 0.05). An unexpected finding was a higher WOB and PTP during EXT as compared with ETT in six of seven of our patients (1.04 vs 0.74 J/L). Examination of breathing pattern and flow volume loops in these two breathing modes raises the possibility that the post-EXT pathology increases in WOB is related to upper airway abnormality. Because of this, our predicted PSmin underestimated the WOB required for spontaneous breathing immediately post EXT.

Hemodynamic responses to exercise after lung transplantation.

A reduced exercise tolerance, maximum oxygen uptake (VO2max), and anaerobic threshold have been reported after lung transplantation (LT). We prospectively assessed the hemodynamic responses to incremental cycle ergometry before and after LT in eight recipients. All recipients underwent a 6-week formal exercise training program. The VO2max increased after versus before LT (13.4 +/- 0.8 vs 9.2 +/- 0.8 ml/min/kg) (p < 0.01). No transition thresholds by analysis of arterial standard bicarbonate were discerned before LT, while the thresholds after LT were abnormally low (VO2 = 9.4 +/- 0.6 ml/min/kg or 35 +/- 3 percent of predicted maximum VO2). An early rise in arterial lactate was similarly observed after LT. Maximum stroke volume index increased in six of seven patients after versus before LT (51 +/- 4 vs 37 +/- 2 ml/beat/m2) (p < 0.05). Three patients demonstrated an increased mean pulmonary arterial pressure at rest, while pressures during exercise were elevated in six. Pulmonary vascular resistance was mildly elevated after LT but decreased appropriately during incremental exercise and was associated with normal cardiac output responses. We conclude that pulmonary vascular abnormalities occurred during hemodynamic exercise testing in the majority of LT recipients; however, exercise limitation was primarily attributed to cardiovascular limitation or to deconditioning in five of the recipients. In the remaining three, the exercise study was considered to be submaximal by virtue of low peak heart rates. A persistent state of deconditioning may have important implications with respect to exercise training regimens after LT.

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

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.