Biomedical subjects

John C Baird

Publications and source records attributed to John C Baird.

13 recordsLinked to original sources

PubMed2007

Responsiveness of patient-reported breathlessness during exercise in persistent asthma.

BACKGROUND: The purpose of the study was to examine the responsiveness of a computerized system whereby the patient reports spontaneously any change in the intensity of breathlessness during exercise. The hypotheses were that hypercapnia would increase and hyperoxia would decrease the slope of power production-breathlessness ratings compared with a control condition during cycle ergometry. METHODS: Thirty adult subjects (15 women and 15 men) with persistent asthma (mean [+/- SD] FEV(1)/FVC ratio, 57 +/- 10%) completed an initial familiarization visit and three study visits. All subjects inhaled two puffs of albuterol (180 microg) in order to standardize lung function prior to exercise. At visits 2 to 4, subjects breathed one of the three gas mixtures administered in a random order while performing a ramp exercise test. The experimental conditions were as follows: hypercapnia (5% carbon dioxide); hyperoxia (40% oxygen); and control (room air). RESULTS: Lung function was the same before and after exercise with the three experimental conditions. With hypercapnia, peak ventilation was increased, peak oxygen consumption, and power production were reduced, the slope of power-breathlessness was increased, and 25 patients (83%) reported breathlessness as the limiting symptom. With hyperoxia, peak ventilation was decreased, peak power production and the slope of power-breathlessness were unchanged, and 16 patients (53%) reported leg discomfort as the limiting symptom. CONCLUSIONS: Breathing 5% carbon dioxide altered physiologic responses and the slope of power production-breathlessness during exercise. The responses to hyperoxia were inconsistent. The continuous method for patient-reported breathlessness was responsive to hypercapnia, but not to hyperoxia, during incremental exercise.

Adult↗

PubMed2006

Continuous ratings of breathlessness during exercise by children and young adults with asthma and healthy controls.

Although it is recommended and common practise for adults with respiratory disease to rate symptoms (e.g., dyspnea and/or leg discomfort) during exercise testing, there are no reports on whether children can rate their perception of breathlessness during exercise. Our aims were to evaluate the ability of children and young adults with asthma to continuously rate breathlessness on the 0-10 category-ratio (CR-10) scale with a computerized system during cycle ergometry, and to compare their results with those of healthy subjects. At an initial visit, subjects were familiarized with equipment and exercise protocol, and practised rating breathlessness while cycling. At a follow-up visit (2-4 days later), subjects performed incremental exercise and rated breathlessness using a computer system, mouse, and monitor. Changing the position of the mouse caused movement of a vertical bar located adjacent to the CR-10 scale to indicate the severity of breathlessness. Baseline characteristics of the 14 subjects with asthma (age, 15 +/- 3 years) and 33 healthy subjects (age, 16 +/- 2 years) were similar. The two groups had comparable levels of fitness as measured by peak oxygen consumption (VO(2)). Correlations between exercise physiologic variables (power production, VO(2), and minute ventilation) and breathlessness ratings were >0.90. Subjects reported progressively more ratings of breathlessness with increasing exercise intensities. There were no differences between groups for slopes, x-intercepts, and absolute thresholds relating physiologic variables and breathlessness. In conclusion, children and young adults with asthma as well as healthy individuals of comparable age successfully used the computerized system to rate breathlessness continuously during cycle ergometry. Both groups reported more ratings of breathlessness with this technique as exercise progressed.

Adolescent↗

PubMed2006

Pain assessment in patients with low back pain: comparison of weekly recall and momentary electronic data.

UNLABELLED: Electronic data collection for monitoring pain has become increasingly popular in clinical research. Past research has shown that electronic diaries improve the timeliness of receipt of data, contribute to higher rates of compliance, and are preferred by patients over paper diaries, and this research suggests that electronic diaries that capture current pain at the moment of reporting result in more reliable ratings than recalled pain ratings. This study compared differences of momentary pain intensity ratings on an electronic visual analog scale (VAS) with weekly recalled pain on a 0 to 10 scale. We asked 21 patients with chronic low back pain to monitor their current pain at least once a day by using a VAS for up to 1 year with a palmtop computer. They were also called once a week and asked to rate their recalled weekly pain orally on a numeric scale from 0 to 10. Patients entered data electronically on average 357 times, for an average of 7.8 times a week. We found that (1) weekly recalled pain agreed highly (r > .90) with averaged momentary pain assessments, (2) neither frequency of electronic monitoring nor variability in momentary pain ratings (high standard deviations) contributed to degree of agreement between momentary and recalled pain, and (3) a ceiling effect was observed in VAS pain ratings as compared with numeric pain ratings. These findings suggest that, among many individuals, weekly recalled pain might be just as useful as momentary data collected through electronic data entry. PERSPECTIVE: Some believe that remembered pain is problematic because of recall bias and that data from frequent momentary pain ratings with electronic diaries are more valid. This study demonstrates that recalled pain is as valid as momentary data for many patients.

Adult↗

PubMed2005

Responsiveness of continuous ratings of dyspnea during exercise in patients with COPD.

PURPOSE: To examine the responsiveness of a new computerized method for patients to provide continuous ratings of dyspnea during exercise in patients with chronic obstructive pulmonary disease (COPD). METHODS: In this randomized, double-blind study the effects of an inhaled bronchodilator (BD), albuterol/ipratropium bromide solution, were compared with normal saline (NS) in 30 patients with COPD (age, 66+/-9 yr; forced expiratory volume in 1 s, 48+/-14% pred). At visit 1, patients were familiarized with the cycle ergometer and computer, monitor, and mouse system to provide continuous ratings of dyspnea during exercise. At subsequent visits 2-3 d apart, patients performed pulmonary function tests followed by incremental ramp (15 W.min-1) and, 1 h later, constant work (at 55% of maximal work capacity) exercise tests. RESULTS: During incremental exercise the slopes of VO2:dyspnea and VE:dyspnea regressions were significantly lower, and patients exercised longer (Delta=0.4 min; P=0.003) with BD therapy compared with NS. During constant work exercise there was a significant reduction in dyspnea at the same exercise duration (5.0+/-2.8 vs 6.2+/-2.8 units on the 0-10 category-ratio scale; P=0.02) and patients exercised longer (Delta=0.9 min; P=0.04) with BD therapy. Changes in lung function at rest did not correlate significantly with changes in dyspnea ratings during exercise. CONCLUSIONS: Continuous ratings of dyspnea were responsive to inhaled bronchodilator therapy during both incremental and constant work exercise tests in patients with symptomatic COPD.

Aged↗

PubMed2004

Usefulness of pain drawings in identifying real or imagined pain: accuracy of pain professionals, nonprofessionals, and a decision model.

UNLABELLED: The aim of this study was to determine the accuracy of pain specialists, nonprofessionals, and a decision model in judging whether a pain diagram was marked by a patient with chronic pain or by a healthy volunteer. Two hundred twenty-eight pain drawings were shown in random order to 10 pain medicine physicians, 10 pain medicine fellows, 10 nonphysician specialists, and 10 nonprofessionals. One half of the drawings (n = 114) had been produced by patients treated at a pain center and the other half (n = 114) by healthy individuals who were instructed to mark the diagrams as if they had a pain problem. The nonprofessionals were found to be 51.5% accurate, pain medicine fellows 52.7%, nonphysician specialists 54.3%, and pain medicine physicians 55.2 % accurate at distinguishing drawings by actual pain patients from drawings from volunteers without pain. A decision model was able to achieve 68.9% accuracy in determining which drawings were made by pain patients and which drawings were made by healthy individuals. The results suggest that subjective assessment of pain drawings alone is not useful in determining whether someone has real or imagined pain. A decision model that makes decisions on the basis of the number of highlighted squares on the pain diagram can identify real pain drawings with greater accuracy than humans. PERSPECTIVE: Pain drawings are clinically useful but have limitations. This study illustrates some of the benefits of computerized pain assessment and highlights the importance of not judging patients on the basis of one source of information.

Adolescent↗

PubMed2004

Development of self-administered versions of modified baseline and transition dyspnea indexes in COPD.

In this study we developed self-administered versions of modified baseline and transition dyspnea indexes and compared the scores obtained by this method with the mean value obtained by two trained interviewers. Twenty-five patients (14 males/11 females) with chronic obstructive disease who had a chief complaint of "breathlessness" were tested. Age was 66+/-11 years; forced expiratory volume in one second was 48+/-23% predicted. The baseline total scores were 5.0+/-1.8 for the interviewers and 5.4+/-2.0 for the self-administered method. For the baseline dyspnea scores the correlations were 0.83 (p<0.0001) between self-administration and the mean value of two interviewers and 0.75 (p<0.0001) between the two interviewers. The transition total scores, obtained an average of 102 days (range, 7-377 days) later, were - 0.1+/-3.0 for the interviewers and - 0.4+/-3.0 for the self-administered method. For the transition dyspnea scores the correlations were 0.94 (p<0.0001) between self-administration and the mean value of two interviewers and 0.83 (p<0.0001) between the two interviewers. The self-administered dyspnea scores had similar correlations with measures of lung function as did the interview dyspnea scores. We conclude that self-administered versions of the modified baseline and transition dyspnea indexes provide comparable scores as those obtained by trained and experienced interviewers. The advantages of the self-administered versions include standardized methodology and computerized scoring.

Aged↗

PubMed2004

Computerized dynamic assessment of pain: comparison of chronic pain patients and healthy controls.

OBJECTIVE: Computerized software holds the potential for the novel assessment of the pain experience of patients with chronic pain not available through traditional paper-and-pencil methods. The aim of this study was to test the feasibility and discriminant validity of a dynamic computer-administered program for the assessment of pain. DESIGN: Three computer-administered programs were created to assess the intensity (dynamic visual analog scale DVAS]), character (dynamic verbal ratings), and location (dynamic pain drawings) of pain. The programs were administered to 115 chronic pain patients recruited from a hospital-based pain management program and 115 age- and gender-matched healthy individuals without pain. The healthy controls were instructed to respond as if they had chronic pain. RESULTS: Analyses showed pain patient DVAS pain intensity ratings to be significantly higher than ratings by the healthy group. Patients selected more words in describing their pain, rated those words higher, and marked significantly more pain locations than the comparison group. However, no differences were found in the DVAS ratings of emotional impact between patients and healthy individuals. CONCLUSIONS: Chronic pain patients were shown to differ from healthy individuals in their assessments of degree of pain intensity and pain location with the use of a novel computerized pain assessment program. Although further investigations are needed, these initial findings support the use of computer methods for the effective assessment of pain.

Chronic Disease↗

PubMed2004

Comparison of continuous and discrete measurements of dyspnea during exercise in patients with COPD and normal subjects.

STUDY OBJECTIVES: The objectives of this study were as follows: (1) to compare results of the discrete and the continuous methods for measuring breathlessness; (2) to examine test-retest reliability; (3) and to test the hypothesis that patients with COPD have higher slopes and lower x-intercepts and absolute thresholds for power production, oxygen consumption (O(2)), and minute ventilation as independent variables and breathlessness ratings as the dependent variable, as compared with healthy subjects. DESIGN: Visit 1 (familiarization) and visit 2 and visit 3 (2 days apart) with randomized assignment of the discrete and continuous methods for subjects rating breathlessness during cycle ergometry. SETTING: Cardiopulmonary exercise laboratory in a university medical center. PARTICIPANTS: Twenty-four patients with COPD (mean age, 66 +/- 8 years [+/- SD]) and 24 healthy subjects (mean age, 66 +/- 10 years). INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Ratings of breathlessness on the Borg scale on cue with subjects moving and pressing the computer mouse button to indicate a rating (discrete method) or by moving the position of the mouse to adjust a vertical bar to indicate a change in breathlessness (continuous method). There were no significant differences in results between visit 2 and visit 3. Although peak exercise variables were similar with the discrete and continuous methods, both groups provided significantly more ratings of breathlessness with the continuous method. Patients with COPD exhibited higher slopes, lower x-intercepts, and lower absolute thresholds (breathlessness rating >/==" BORDER="0"> 0.5 ["just noticeable"] on the Borg scale) for power production and O(2)-breathlessness compared with healthy subjects (p < 0.05). CONCLUSIONS: Elderly patients with COPD and healthy subjects are able to use the continuous method successfully. Reliability is excellent for both methods. The continuous method provides a greater number of breathlessness ratings over the course of exercise, and allows the clinician to calculate an absolute threshold and just-noticeable differences. Regression parameters and absolute thresholds discriminate between patients with COPD and healthy subjects.

Aged↗

PubMed2003

Cluster analysis classification of SF-36 profiles for patients with spinal pain.

STUDY DESIGN: A k-means cluster analysis of patients with spinal and radicular pain based on the SF-36 Health Survey scales. OBJECTIVE: The aim was to determine whether spine patients fall into clusters according to self-reported health status as measured by the SF-36 and to determine if clustering is similar across four common diagnostic categories: herniated disc, spinal stenosis, spondylosis, and chronic pain syndrome. SUMMARY OF BACKGROUND DATA: Cognitive-behavioral classifications of chronic pain patients have previously identified three patient groups described as Dysfunctional, Interpersonally Distressed, and Minimizers/Adaptive Copers. The purpose of these classifications is to facilitate and direct treatment based not only on biomedical diagnosis but also on emotional, social, and behavioral diagnoses. This type of analysis has not been done on the quality-of-life scores of patients with specific spinal diagnoses. METHODS: Health status data were reviewed from the initial visits of 15,748 spine patients in the National Spine Network database. Based on the eight scales of the SF-36, k-means cluster analysis divided the National Spine Network population into distinct clusters of similar patients. Clustering was performed separately for each clinical diagnosis group. RESULTS: In all four diagnostic categories, cluster analysis classified patients into three groups. Group 1 had fairly high (relative to the entire sample) scores on all scales and was labeled "Highly Functional." Group 2 had low measures on physical variables but comparatively high scores on the mental scales. These were labeled "Emotional Adapters." Group 3 had low scores on all scales. These patients were labeled "Dysfunctional." Although patients in each diagnostic category fell into one of the three groups, the proportion of patients within each group was quite different among chronic pain patients as compared to the other three diagnostic groups. For example, 29% of herniated disc patients were in the Highly Functional group, whereas only 14% of patients in chronic pain were categorized as Highly Functional. Thirty-three percent of spondylosis patients were classified as Dysfunctional compared with 51% of chronic pain patients. CONCLUSIONS: Patients with spinal pain fall into three groups according to their profile of scores on the SF-36 Health Survey. It is proposed that such empirical groupings can guide decision-making in selecting the most appropriate therapies.

Cluster Analysis↗

PubMed2003

Evaluation of dyspnea in the elderly.

The word "dyspnea" encompasses many different features. It can be considered to be a sensation, a symptom, or an illness. From a practical perspective many physicians and nurses use dyspnea to refer to difficult or labored breathing or an uncomfortable awareness of breathing. The American Thoracic Society recently defined dyspnea as a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity.

Aged↗

PubMed2003

Reliability and validity of an interactive computer method for rating quality of life.

OBJECTIVE: The purpose of this study was to describe the reliability and validity of an interactive computer method that assesses the quality of life of patients in chronic pain and healthy individuals. METHODS: A software program to assess 21 aspects of quality of life was administered to 88 pain patients on two occasions separated by an average of 30 days. Comparison data were obtained from 105 healthy individuals retested after an average of 16 days. RESULTS: For both groups, moderate test-retest correlations occurred for mean ratings based on an aggregation of data for all variables, single global ratings, and single ratings of individual variables. Patients in chronic pain scored significantly lower on all quality of life variables than did healthy individuals. High correlations were obtained between mean ratings from the present study and those from an earlier investigation using the same method. CONCLUSIONS: The interactive computer method is both reliable and valid as a means to assess quality of life for patients in chronic pain as well as for healthy individuals.

Adult↗

PubMed2002

Response scale transfer for visual speed.

By reversing the presentation order and frequency of stimuli between two series of trials, we studied how the category scale for visual speed is transferred across stimulus contexts. Participants judged five stimulus speeds, using three categories (slow, moderate, and fast). In Experiment 1, mainly frequent speeds (either low or high) occurred on the initial trials. This manipulation produced divergent preshift ratings for identical stimuli. Although subsequent reversal of stimulus context resulted in a reversal of scales, the adjustment was incomplete: The postshift ratings did not match the comparable preshift ones. In Experiment 2, mainly infrequent speeds were presented initially. Now the preshift ratings coincided, but higher postshift ratings occurred with the frequent high-speed rather than with the frequent low-speed stimuli. We conclude that with transfer into a new context, the spontaneous adjustment of response scale is determined (1) by the preshift primacy and the postshift frequency effects and (2) by the preshift frequency effect extended to the postshift trials.

Adult↗

PubMedDate not supplied

Cluster analysis of SF-36 scales as a predictor of spinal pain patients response to a multidisciplinary pain management approach beginning with epidural steroid injection.

OBJECTIVE: To investigate whether grouping of patients with back pain into similar behavioral patient profiles using SF-36 scores is predictive of outcome following 1-year treatment in a multidisciplinary spine center beginning with referral for epidural steroid injection. DESIGN: A prospective observational study was conducted on 81 consecutive patients selected for epidural steroid injections by independent physicians following common institutional criteria. Each patient completed a baseline SF-36 questionnaire as well as a numerical response pain scale. The initial SF-36 data were used to place each patient into one of three subgroups (Highly Functional, Emotional Adapters, and Dysfunctional). Follow-up SF-36 and numerical response pain scale questionnaires were completed by the patients at 1 month and 12 months following the initial epidural steroid injection. RESULTS: Results revealed significant improvement among all three patient subgroups following multidisciplinary treatment at both 1 month and 12 months. Few differences in outcome occurred among the subgroups. CONCLUSION: The SF-36-determined subgroups did not predict response to a multidisciplinary pain clinic. All three subgroups showed similar improvement following treatment.

Adult↗