Assessment of the impact of 10-day intermittent hypoxia on the autonomic control measured by heart rate variability.

PURPOSE: The purpose of this study is to establish the alterations in the activity of the autonomic nervous system (ANS) via heart rate variability (HRV) in subjects exposed to 1 h of exogenous hypoxia for 10 consecutive days. METHODS: Twelve healthy non-smoker males at mean age of 29.8 ± 7.4 (mean ± SD) breathed hypoxic air delivered through hypoxicator (FiО2 = 12.3% ± 1.5%) for 1 h in 10 consecutive days. Pulse oximetry and electrocardiography were monitored during the visit and HRV was calculated for the entire 1-h hypoxic period. RESULTS: Comparing the last hypoxic visit to the first, subjects had higher standard deviation of normal-to-normal interbeat intervals (SDNNs) (65.7 ± 32.5 vs. 81.1 ± 32.0 ms, p = 0.013) and root mean square of successive R-R interval difference (RMSSD) (58.1 ± 30.9 vs. 76.5 ± 34.6 ms, p = 0.029) as well as higher lnTotal power (8.1 ± 1.1 vs. 8.5 ± 0.9 ms2, p = 0.015) and high frequency (lnHF) (6.8 ± 1.3 vs. 7.5 ± 1.2 ms2, p = 0.05) and lower LF/HF (2.4 ± 1.4 vs. 1.5 ± 1.0, p = 0.026). Changes in saturation (87.0 ± 7.1 vs. 90.8 ± 5.0%, p = 0.039) and heart rate (67.1 ± 8.9 vs. 62.5 ± 6.0 beats/min, p = 0.040) were also observed. CONCLUSIONS: Intermittent hypoxic training consisting of 1-h hypoxic exposure for 10 consecutive days could diminish the effects of acute exogenous hypoxia on the ANS characterized by an increased autonomic control (SDNN and total power) with augmentation of the parasympathetic nervous system activity (increased RMSSD and HF and decreased LF/HF). Therefore, it could be applied as a pre-acclimatization technique aiming at an increase in the autonomic control and oxygen saturation in subjects with upcoming sojourn to high altitude.

Standardized peak exercise perception score: validation of a new index of effort perception.

PURPOSE: Standardized peak exercise perception score (SPEPS) is an index representing patient effort perception defined as SPEPS = Borg/METs, where Borg is the Borg CR-10 at maximal exercise intensity and METs is maximal metabolic equivalents. The purpose of the study was to assess the validity of SPEPS in different patient groups and to examine its applicability for evaluation of exercise training outcomes. METHODS: Patients (n = 17) with chronic heart failure (CHF, New York Heart Association [NYHA] II and III functional class; ejection fraction= 31 +/- 14%), 16 patients with chronic obstructive pulmonary disease (COPD, forced expiratory volume in 1 second - FEV(1)%= 51 +/- 14%), and 16 age- and body mass index-matched controls formed the primary study group. An additional 22 ambulatory patients with stable CHF (NYHA II-III) were randomized to training and nontraining groups to test the effect of 8 weeks' exercise training on SPEPS. RESULTS: Patients showed reduced exercise capacity (V(O)(2), mL*kg(-1)* min(-1)) = 18.8 +/- 3.8 (CHF) vs 21.1 +/- 5.1 (COPD) vs 29.9 +/- 5.2 (control), corresponding to SPEPS values: 1.15 +/- 0.36 (CHF) vs 0.82 +/- 0.26 (COPD) vs 0.55 +/- 0.22 (control); P < .001. The reduction in SPEPS was the largest compared with the other tested parameters after training and correlated strongly with change in Minnesota Living with Heart Failure Questionnaire (rho= 0.75, P < .001). CONCLUSION: SPEPS is a reliable new index for discriminating perceived exertion at the end of exercise test in different groups of patients, presenting both construct and concurrent validity. It is a potent parameter for evaluation of the outcomes in training programs.

Pictorial and verbal category-ratio scales for effort estimation in children.

BACKGROUND: Research on the diverse aspects of exercise performance in childhood in the past 20 years has included an increase in the study of perceived exertion. OBJECTIVE: The aim of this study was to compare children's ratings of effort perception by means of the Borg Category-Ratio Perceived Exertion (CR-10) Scale and a pictorial version of the Children's Effort Rating Table (Pictorial-CERT) scale, and to assess the long-term repeatability of the two scales. METHODS: Fifty healthy children (25 girls and 25 boys; initially aged 10.4 +/- 0.5 years) participated in three incremental treadmill tests until volitional exhaustion or a maximal gradient of 22% at 5.4 km/h was attained. The first two tests (T1 and T2) were at an interval of 1 month. The third test (T3) took place 3 years later and utilized exactly the same protocol. RESULTS: Perceived exertion correlated significantly with measures of exercise intensity - minute ventilation, heart rate and oxygen uptake for the whole group. The range of correlations for all tests was significantly higher for the Pictorial-CERT (r = 0.62-0.88 and r = 0.59-0.71 for the Pictorial-CERT and CR-10 respectively). Intraclass correlation coefficients between T1 and T2 were significantly higher for the Pictorial-CERT in comparison with the CR-10 (0.77 vs. 0.54, respectively; z = -2.07; P = 0.038). CONCLUSION: The Pictorial-CERT is more appropriate for use with children of this age range and appears to be more reproducible than the Borg CR-10 Scale. Concurrent and construct validity evidence promotes the use of the Pictorial-CERT by junior children.

Exercise performance and ventilatory efficiency in patients with mild and moderate liver cirrhosis.

1. The impact of ventilatory efficiency on reduced exercise capacity and recovery oxygen kinetics has not been addressed in cirrhotic patients. The aim of the present study was to investigate exercise performance and ventilatory efficiency in patients with mild and moderate liver cirrhosis (LC). 2. Nineteen male non-hypoxic patients with LC (age 51.3 +/- 9.1 years; body mass index (BMI) 25.6 +/- 3.6 kg/m(2)) classified by the Child-Pugh score as class A (n = 7) and class B (n = 12) and 19 age- and BMI-matched controls participated in the study. Subjects undertook maximal incremental exercise testing on a treadmill using the Bruce protocol. 3. Patients with LC showed a reduced diffusion capacity (D(L,CO)%) compared with controls (74.6 +/- 15.2 vs 95.6 +/- 12.9%, respectively; P < 0.001), but a comparable volume standardized diffusion coefficient (1.33 +/- 0.22 vs 1.45 +/- 0.18 mmol/min per kPa per L, respectively; P = 0.74). Patients with LC had a significantly lower exercise capacity compared with controls (VO(2 max) 23.8 +/- 3.8 vs 30.6 +/- 4.4 mL/min per kg, respectively; P < 0.001). Recovery oxygen kinetics were also impaired in LC patients compared with controls (104.6 +/- 19.3 vs 84.4 +/- 22.7 s, respectively; P = 0.012). The chronotropic index was significantly lower in the LC group compared with controls (0.67 +/- 0.19 vs 0.82 +/- 0.17, respectively; P = 0.030) and LC patients showed higher ventilatory equivalents (30.4 +/- 3.8 vs 26.3 +/- 2.3, respectively; P < 0.001) and lower oxygen uptake efficiency slope values (2187 +/- 445 vs 2745 +/- 473 mL/min per log(10)L, respectively; P < 0.001) compared with controls, which is indicative of decreased ventilatory efficiency. Patients with LC also had a higher standardized maximal exercise perception score (SMEPS) compared with controls (0.62 +/- 0.18 vs 0.46 +/- 0.15, respectively; P = 0.011). Moderate negative correlations were found between Child-Pugh score and VO(2 max)% (r = -0.496; P = 0.031). 4. In conclusion, patients with mild and moderate LC have reduced exercise capacity, which correlates with Child-Pugh score, as well as reduced chronotropic index and prolonged recovery oxygen uptake kinetics. The results suggest worsened ventilatory efficiency during exercise and cardiopulmonary reasons for the higher SMEPS in these patients.

Modified treadmill protocol for evaluation of physical fitness in pediatric age group--comparison with Bruce and Balke protocols.

The aim of this study was to compare classical Balke and Bruce protocols with our modification of Balke protocol in pediatric cardiorespiratory diagnostics. The modification of Balke consists of nine stages per 1 min at a constant velocity of 5.6 km x h(-1) and increasing elevation from 6% to 22% in 2% increments. Sixty healthy children (mean age = 13.3+/-0.2 years; BMI = 18.8+/-0.6 kg x m(-2); mean +/- 95% CI), divided into three groups of 20 children each, matched by age, height and BMI performed integrative cardiopulmonary exercise testing using one of the treadmill protocols mentioned. At the end of each exercise increment and throughout the recovery period the children were asked to rate the perceived exertion (RPE) using the Borg Category Ratio scale--CR-10. Exercise results showed that Balke protocol had the longest duration (21.7+/-0.6 min.) and the lowest values for VO2/kg (34.2+/-1.8 ml x min(-1) x kg(-1)) due to the minimal workload increments. Bruce protocol had intermediate duration (14.9+/-1.1 min.) and children achieved the highest VO2/kg (48.6+/-2.7 ml x min(-1) x kg(-1)) but the test is symptom-limited which is ethically unacceptable in childhood. Exercise data revealed that our modification of the classical Balke protocol had an optimal duration (11 min.) and yielded peak VO2/kg values (39.4+/-2.3 ml x min(-1) x kg(-1)) adequate for evaluation of children's exercise capacity. Children's ratings of perceived exertion were highest in Bruce protocol (6.5+/-0.4) and lowest in the original Balke protocol (4.5+/-0.8). In conclusion, the modification of Balke protocol is suitable and reliable for screening and clinical testing in pediatric age group.

Exercise performance and oxygen uptake efficiency slope in obese children performing standardized exercise.

Oxygen uptake efficiency slope (OUES) is an index meant to provide an objective measure of cardiopulmonary function at submaximal exercise. The aim was to study the exercise performance and OUES in obese children performing standardized exercise. Sixty children aged 6-17 years performed incremental treadmill exercise test. They were divided into two groups matched by age, sex and height: thirty obese subjects (15 girls/15 boys; BMI = 27.4+/-1.7 m x kg(-2)) and 30 controls (BMI = 18.8+/-1.0 m x kg(-2)). Perceived exertion was assessed by means of CR-10 Borg scale. The duration of the exercise for the obese children was significantly shorter than for controls (p = 0.010) but obese children had greater absolute values for oxygen uptake (VO2 peak mL x min(-1) = 1907+/-249 vs. 1495+/-208; p = 0.013) which, adjusted for body mass, decreased significantly (VO2/kg mL x min(-1) x kg(-1) = 29.2+/-1.4 vs. 33.6+/-1.3; p < 0.001). OUES correlated strongly with VO2 peak (r = 0.91) and oxygen pulse (r = 0.80), as well as with anthropometric variables height (r = 0.88) and age (r = 0.83). Extremely high correlation was found between OUES calculated for 100% of exercise duration and OUES at the anaerobic threshold (r = 0.979; p < 0.001). No significant differences were found between the studied groups concerning the absolute values of OUES. Obese children rated perceived exertion significantly higher than controls (Borg score 6.2+/-0.4 vs. 5.2+/-0.4; p = 0.001). In conclusion, the absolute metabolic cost of exercise and perceived exertion were higher in the obesity group. OUES is an objective measure of cardiopulmonary reserve that doesn't require a maximal effort but it is considerably dependent on anthropometric variables which impedes its interpretation as exercise index in childhood.

University of Cincinnati Dyspnea Questionnaire for Evaluation of Dyspnoea during physical and speech activities in patients with chronic obstructive pulmonary disease: a validation analysis.

University of Cincinnati Dyspnea Questionnaire (UCDQ) was developed to measure the impact of dyspnoea during (1) physical activity (Phys), (2) speech activity (Speech) and (3) simultaneous speech and physical activity (Comb). The aim of this study was to evaluate the validity of UCDQ in COPD patients, comparing it to a large set of dyspnoeic indices and functional parameters. Fifty COPD patients (age 58.7 +/- 9.1 years, FEV1%pred = 39.3 +/- 17.0%, Baseline Dyspnoea Index (BDI) = 4.9 +/- 2.5, Six Minute Walk Distance (6MWD) = 373 +/- 128 m, Symptoms score = 9.4 +/- 2.5; mean +/- SD) participated in the study. We found the following mean scores for the three sections of the questionnaire: Phys = 3.5 +/- 0.9; Speech = 2.4 +/- 1.1; Comb = 4.2 +/- 1.0, meaning that patients report the most breathlessness during the combination of speaking and physical activity and the least breathlessness during speech activities. All three section of UCDQ had significant strong correlation with dyspnoea indices (BDI, Borg, MRC, OCD), 6MWD and symptoms score, which proves its concurrent and construct validity. Differentiation of patients by speech section (=3<) discriminated them significantly with respect to all dyspnoeic indices, symptoms score and 6MWD. All three dimensions of UCDQ had high test-retest reliability - ICC between 0.76 and 0.93. Factor analysis yielded three interpretable factors, as all dyspnoeic indices, three sections of UCDQ, symptoms score and 6MWD were loaded on the first factor. In conclusion, UCDQ provides valid and reliable information about the effect of dyspnoea on speech and daily activities.

Ventilatory efficiency and rate of perceived exertion in obese and non-obese children performing standardized exercise.

Sixty children, in the age span 6-17 years originally divided into two groups, matched by age, sex and height--30 obese subjects [15 girls/15 boys; body mass index (BMI) = 27.4 +/- 4.5 m kg-2; ideal body weight (IBW) range = 122-185%] and 30 controls (BMI = 18.8 +/- 2.7 m kg-2) performed incremental treadmill exercise test. Perceived exertion was assessed by means of Category-Ratio Borg scale. The duration of the exercise for the children in the obesity group was significantly shorter than controls (P = 0.010) but obese children have greater absolute values for oxygen uptake (VO2peak ml min-1 = 1907 +/- 671 versus 1495 +/- 562; P = 0.013) and ventilatory variables (VE, VT), which adjusted for body mass decrease significantly (VO2/kg ml min-1 kg-1 = 29.2 +/- 3.8 versus 33.6 +/- 3.5; P < 0.001). Among the various methods for 'normalizing' absolute values of VO2peak for body size, dividing it by body surface area (BSA) yielded the best results (VO2/BSA ml min-1 m-2 = 43.5 +/- 4.6 versus 44.7 +/- 5.6; P = 0.335). The ventilatory efficiency determined either as a slope of VE versus VCO2 or as a simple ratio at anaerobic threshold did not differ between obese and non-obese children in the incremental and recovery periods of exercise. There was a negative correlation of VE/VCO2 slope with age and anthropometric parameters. Obese children rated perceived exertion significantly higher than controls despite the standard workload (Borg score = 6.2 +/- 1.2 versus 5.2 +/- 1.1; P = 0.001). In conclusion, the absolute metabolic cost of exercise is higher in the obesity group compared with the control subjects. Both groups have similar ventilatory efficiency but an increased awareness of fatigue that furthermore limits their physical capacity.

A factor analysis of dyspnea indexes and lung function parameters in patients with chronic obstructive pulmonary disease.

The purpose of the present study was to investigate the correlation between dyspnea ratings and a large group of lung function parameters, and extract those factors that best reflect the functional profile of patients with COPD using factor analysis. Ninety nine patients with COPD in stable clinical condition (age 60 +/- 8 years, ATS score = 2.5 +/- 0.9, FEV1% pred. = 33 +/- 13%) were included in the study. The factor analysis of the results yielded 5 factors which accounted for 80.1% of the total variance of the changes. The highest coefficients found between the factors and the original group of variables after Varimax rotation are given in the following table: Factor 1: Oxygen-cost diagram: 0.92; ATS dyspnea score: -0.80; TL,CO/VA: 0.78; Factor 2: FEV1% pred.: 0.87; FEV1/VC%: 0.86; FEV1L: 0.79; Factor 3: MIF50% pred.: 0.85; FIV1% pred.: 0.76; PImax: 0.67; Factor 4: PaCO2: -0.81; SaO2: 0.77; Mean pulmonary arterial pressure: -0.67 Factor 5: Age: 0.88; Six minutes walk distance: -0.72 The factor analysis showed that the functional profile of COPD patients has several dimensions. Therefore, in order to have COPD comprehensively evaluated, assessment of dyspnea and the respective set of lung function parameters (exercise capacity, forced inspiration and pulmonary hemodynamics), should be included in the battery of tests, besides the conventional tests.

A patient with a severe chronic airway obstruction and preserved exercise capacity (a case report).

We report a patient with chronic obstructive pulmonary disease (COPD) in whom severe lung function disorders are combined with completely preserved exercise capacity. We assessed the exercise capacity of a 44-year-old man (height 155 cm, BMI 19.6 kg.m-2, FEV1%pred. = 30.9%, FRC%pred. = 158%, KCO%pred. = 46.2%, PaO2 = 64.0 mmHg, Medical Research Council Dyspnea scale = 1, Baseline Dyspnea Index = 10) by the 6-minute walking distance test (6MWD) and the symptom-limited cardiopulmonary exercise test (CPET) on a treadmill using the Bruce protocol. The patient was able to walk 667 meters in the test and achieved peak relative oxygen consumption (VO2/kg) of 21.9 mL.min-1.kg-1. We attribute the preserved exercise capacity of the patient to the combined beneficial effect of the following factors: 1. Efficient extraction of the hemoglobin-transported oxygen from the alveoli (P50 = 3.10 kPa). 2. Optimal right ventricle remodelling with mild hypertrophy, without dilatation and congestion. 3. Hypoxic normoxemia without polyglobulia, resulting in good rheologic properties of blood. 4. A preserved locomotory activity of the patient. Such a combination of severe lung function disorders with mildly pronounced dyspnea and preserved exercise capacity supports the concept that the function profile of COPD patients is multidimensional and therefore such patients should have a complete assessment of their disability condition.

[Diagnostic algorithm and software for assessment and follow-up of dyspnea]. / [Diagnostichen algorit'm i programa za otsenka i proslediavane na dispneiata]

Breathlessness is a common complaint among patients with lung and heart diseases. It is a complex, multidimensional symptom with descriptive and quantitative aspects. The aim of this study is to constitute a set of questionnaires and scales for adequate assessment of dyspnea and their combination in diagnostic algorithm with various ranges. In order to achieve this goal, we developed a software product DISKO with the following characteristics: Includes the basic instruments for assessing dyspnea in all dimensions--verbal (descriptive) characteristic, everyday activities and exercise dyspnea, as well as its impact on the patients' quality of life. Proposes minimal, optimal and comprehensive algorithm for assessment and follow up of dyspnea. Presents a convenient interface and an ability to configure a flexible data base easy for browsing and handling. Proposed tests and algorithm for dyspnea assessment make it easier for the physician to diagnose and follow up chronically ill patients whose major complaint is dyspnea. The software product DISKO is compliant with the modern requirements for medical software and can be utilized in the process of diagnostic, education and scientific research.

Ventilatory response to exercise and rating of perceived exertion in two pediatric age groups.

The aim of this paper is to study the differences in ventilatory response to exercise in prepubertal and pubertal children. One hundred children in the following groups: 10-year-olds (25 boys/25 girls) and 13-year-olds (25 boys/25 girls) performed sub maximal treadmill stress test, using modified Balke protocol. All of them went through complex pulmonary function testing and complete anthropometrics measurements, including skinfold thickness. The relative oxygen consumption for the whole group is 38.5 +/- 4.5 mL/min/kg (mean +/- SD). The girls had higher percent fat than boys in both groups (24% vs. 16% in the first group and 27% vs. 18% in the second). With age VO2peak grows parallel with minute ventilation, tidal volume and a tendency towards lowering the breathing frequency is observed irrespective of the sex. We found significant sex differences in ventilatory equivalents for oxygen and carbon dioxide in the second group. VE/VCO2 for the boys decreased from 30.6 +/- 3.1 to 27.6 +/- 2.9; p = 0.002, but remains unchanged in girls. Another interesting fact is that older children rated perceived exertion significantly higher (Borg score 4.6 +/- 0.9 vs. 5.5 +/- 1.4; p < 0.05) despite the standard load. In conclusion there are age and sex differences in some aspects of ventilatory response in pediatric age group.

Effect of complex sanatorium treatment on some dyspnea indices in patients with chronic obstructive pulmonary disease.

The complex treatment of patients with chronic obstructive pulmonary disease (COPD) administered in a sanatorium environment is an effective therapeutic option for this condition as it involves conduction of a combination of climatic, therapeutic and rehabilitation procedures for a longer period of time. We studied the effect of this therapeutic modality on the dyspnea indices of COPD patients and the implication these indices have for the outcome of the treatment. The study was performed in the sanatorium of the State Hospital for Lung Diseases in Raduntzi, Bulgaria. It included 75 patients (65 men, 11 women) with different forms of stable COPD (mean age, 56.8 +/- 1.0 years, mean +/- SEM, FEV1% predicted--37.3 +/- 1.6%, mean duration of sanatorium stay 14 +/- 0.4 days). During the stay the patients received anti-obstructive and anti-inflammatory therapy based on the clinical discretion of the attending physician. All patients attended a rehabilitation programme according to their conditions; oxygen therapy was used in three patients. Of the 75 patients, 50 (66.7%) showed improvement at discharge, 21 (28%) had no improvement, and 4 (5.3%) were discharged in deteriorated condition. The complex treatment resulted in a minimal but statistically significant improvement of the basic spirographic and dyspnea parameters. This improvement depended not so much on the type of therapy administered as on the initial dyspnea and blood gas parameters. The body mass index (BMI) can also be used as a prognostic indicator especially if it is lower than 20 kg/m2. The lower this index is the lower the basic functional parameters are--in spite of using all available treatments, our patients with low body mass index rarely showed any noticeable improvement.

Effects of short-term exercise training in patients with heart failure.

Heart failure is a debilitating disorder which limits exercise capacity and produces a poor quality of life. The present study was designed to determine the effects of an exercise training program on patients with CHF NYHA functional class II-III, attributed to left ventricular systolic dysfunction and dilated left ventricle. Twenty-two ambulatory male patients with stable CHF were randomised to a training (n = 15) and a control group (n = 7). A symptom limited ramp cardiopulmonary exercise test with gas exchange analysis was performed at baseline after 4 and 8 weeks. The training group underwent an exercise training program at 50% of peak oxygen uptake for eight weeks. The control group was not exercised. After 8 weeks, compared with baseline, there were statistically significant increase in peak oxygen uptake, peak workload, anaerobic threshold, oxygen pulse, RPP, ventilation and the duration of the test only in trained patients. The reduction in scores tested by the Minnesota Living with Heart Failure questionnaire (p < 0.001) and Borg dyspnea rating score (p < 0.001) reflect the reduction of symptoms and the improvement in health-related quality of life. Carefully selected patients with moderate to severe CHF can achieve significant improvements of exercise capacity and quality of life with exercise training and can safely participate in a conditioning program.

Functional parameters in pulmonary bullous emphysema.

OBJECTIVE: 1. compare a large set of functional parameters in patients with bullous emphysema and patients with nonbullous emphysema. 2. To compare a chest radiographs (CHR) and a high resolution computed tomography (HRCT) in the clinical assessment of bullous emphysema. MATERIAL AND METHODS: The study population included 43 stable COPD patients (age = 59 +/- 9 years; pack/year (P/Y) = 39 +/- 19; ATS dyspnea score = 2.3 +/- 0.9; FEV1%pred. = 30 +/- = 10%; KCO%pred. = 49 +/- 16%; 6MWD (six minute walk distance) = 395 +/- 103 m; mean +/- SD). The patients were divided into two groups (patients with and without bullae) by a HRCT. In most of the cases the size of the bullae, measured by CT scan, was less than 15 mm. Twenty two CHRs were read independently by three experienced chest radiologists who had no knowledge of the CT scan data. RESULTS: Statistically significant differences were found between the groups with bullous (n = 19) and nonbullous (n = 24) emphysema in FEV1 (p < 0.001); VC (p = 0.001); BMI (p = 0.018); Borg after exercise (p = 0.021); FEV1/VC% (p = 0.025) and P/Y (p = 0.034). The sensitivity of chest radiographs compared with CT scan regarding the small bullae was very low: 27.7% in radiologist I, 12.3% in radiologist II, and 21.5% in radiologist III. CONCLUSIONS: 1. The patients with bullous emphysema have statistically significant lower lung function indices (FEV1, VC, FEV1/VC%) and BMI than those with nonbullous emphysema. 2. Patients with bullous emphysema have higher level of dyspnea score after 6MWD and higher pack-year smoking status than those with nonbullous emphysema. 3. For the clinical evaluation of emphysema the information derived from a standardised reading of the CXR is not as valuable as that derived from the CT scan.

Effect of CPAP on breathlessness perception in healthy subjects during methacholine induced bronchoconstriction.

Application of continuous positive airway pressure (CPAP) in asthmatic patients decreases breathlessness (B). The effect of CPAP on induced bronchoconstriction was studied in healthy subjects. The changes in B were related to changes in lung function indices. In nine healthy volunteers, males aged 20-27 years, acute bronchoconstriction was induced by inhalation of 1 to 128 mg/ml methacholine (M). CPAP (0.5 kPa) was then applied for 1 min. It was followed by inhalation of albuterol. Forced expiratory volume in 1 s (FEV1) and vital capacity (VC) were measured by spirometry and end expiratory lung level (EELL), to derive inspiratory capacity (IC), by inductive plethysmography. B was assessed by Borg scale. After the maximal concentration of M, FEV1 decreased by 14% (p < 0.01) as compared to the control values and Borg score (BS) increased to 2.4 (p < 0.01). In 7 out of 9 subjects we found a significant (p < 0.05) correlation between the changes in FEV1 and BS. BS decreased during CPAP (p < 0.01) and it further decreased significantly after albuterol. There was no correlation between the changes in IC and FEV1 during bronchoconstriction, or between IC and BS during CPAP. In conclusion, in healthy subjects with induced bronchoconstriction CPAP decreased significantly BS, which was further improved by inhalation of albuterol. B was related to changes in FEV1 but not in IC.

Algorithm for assessment of the oxygen, acid-base and electrolyte status (ALBOA BEACH).

To achieve accurate interpretation of blood gas analysis data in intensive care units, the oxygen, acid-base and electrolyte-metabolite profile of arterial blood should be comprehensively and adequately monitored and assessed. A number of diagnostic software programmes have been developed to assist clinicians in this and to help improve instruction in this field. In the present study we describe an algorithm and a programme for assessment of the oxygen, acid-base and electrolyte status of the arterial blood. The algorithm, as well as the software programme, is named ALBOA BEACH, which is an acronym of the programme's full name--ALgorithm for Blood Oxygen, Acid-Base, Electrolyte And respective CHarts. The algorithm takes account of the latest achievements in blood-gas analysis; it can be used both in on-line and off-line modes and is useful in the laboratory and pathophysiological assessment of blood-gas disorders. The algorithm is based on a rigorous pathophysiological analysis and the interpretation achieved as a result is much more accurate than usual. Thus it provides a most reliable basis for taking the right clinical decision and making the proper prognosis of the possible critical conditions. The algorithm also provides additional bases for interpretations of data in the borderline zones, with due warnings in cases of absence of physiological coherence between the various parameters and modules. The programme is designed to be used with the modern multifunctional blood-gas analysers; it can be of assistance in making diagnoses, in the training and research activity in the intensive care units and specialised blood gas laboratories.

Comprehensive assessment of ventilatory functions of patients with chronic heart failure.

OBJECTIVE: A comprehensive assessment of the ventilatory functions of patients with chronic heart failure (CHF) both at rest and during a cardiopulmonary exercise test (CPET). We studied 42 males, divided into two groups--patients with CHF (n = 21) and age, weight, height and BMI matched healthy controls (n = 21). All subjects underwent a symptom-limited ramp CPET, arterial blood gas analysis, and complex functional examination of the pulmonary system. Subjective rating of dyspnea and exertion were measured by the Borg and ATS dyspnea scales. CHF patients showed a slight, but statistically significant decrease of the spirographic and diffusion parameters, as well as of the indices of respiratory muscle strength. There were no changes in blood gases and in tidal breathing parameters. The exercise capacity was markedly reduced (VO2peak ml.min-1 1352 +/- 335 CHF patients vs 2077 +/- 276 healthy controls; p < 0.001) and the anaerobic threshold occurred earlier (< 40% of predicted VO2peak) during CPET in CHF patients. The increase in VE/VCO2 in CHF patients (35.7 +/- 5.1 CHF; 28.9 +/- 2.5 HC, p < 0.001) indicates a compromised ventilatory efficiency which leads to a higher dyspneic cost of exercise (Borg peak 9.5 +/- 1.03 CHF; 6.0 +/- 1.28 HC; p < 0.001) as compared with healthy controls.