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Results for “Maximal Voluntary Ventilation”

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PubMed1983

Spirometric diagnosis of upper airway obstruction.

We evaluated the results of routine spirometry in patients with well-documented upper airway obstruction (UAO) to determine if this readily available form of pulmonary function testing could reliably identify patients with this abnormality. Our results indicate that, although individual standard spirometric indexes could not identify these patients, ratios derived from these indexes provided excellent discrimination between patients with UAO and patients with a variety of lung diseases. A ratio of maximal voluntary ventilation to forced expiratory volume in 1 s of less than 25 was present in ten (66%) of 15 patients with UAO and only one (1%) of 100 comparison patients. A ratio of forced inspiratory flow between 25% and 75% of the vital capacity to forced expiratory flow between 25% and 75% of the vital capacity of less than 1 was found in 12 (80%) of 15 patients with UAO, but in only four (4%) of 100 comparison patients. All patients with UAO had one ratio abnormal. We conclude that spirometry remains a valuable procedure in the diagnosis of UAO.

Adult↗

PubMed1993

Estimation of ventilatory capacity during submaximal exercise.

There is presently no precise way to determine ventilatory capacity for a given individual during exercise; however, this information would be helpful in evaluating ventilatory reserve during exercise. Using schematic representations of maximal expiratory flow-volume curves and individual maximal expiratory flow-volume curves from four subjects, we describe a technique for estimating ventilatory capacity. In these subjects, we measured maximal expiratory flow-volume loops at rest and tidal flow-volume loops and inspiratory capacity (IC) during submaximal cycle ergometry. We also compared minute ventilation (VE) during submaximal exercise with calculated ventilatory maxima (VEmaxCal) and with maximal voluntary ventilation (MVV) to estimate ventilatory reserve. Using the schematic flow-volume curves, we demonstrated the theoretical effect of maximal expiratory flow and lung volume on ventilatory capacity and breathing pattern. In the subjects, we observed that the estimation of ventilatory reserve with use of VE/VEmaxCal was most helpful in indicating when subjects were approaching maximal expiratory flow over a large portion of tidal volume, especially at submaximal exercise levels where VE/VEmaxCal and VE/MVV differed the most. These data suggest that this technique may be useful in estimating ventilatory capacity, which could then be used to evaluate ventilatory reserve during exercise.

Adult↗

PubMed1992

Repeated measurements of pulmonary function following spinal cord injury.

Twelve subjects (11 males, 1 female) with complete spinal cord lesion (level of lesion ranging from C4 to T10), with a mean age of 23.5 years participated in pulmonary function testing (PFT). Inspiratory and expiratory flow measurements were made at 2-month intervals from 25 to 351 days post injury. The values were interpolated and extrapolated to common dates to facilitate comparison. The effect of time on pulmonary function was determined by a repeated measures ANOVA. Forced expiratory volume in 1 second (FEV1.0) significantly increased during the course of the study (40%, p < 0.05), but increases in forced vital capacity (FVC) (32.5%) and maximal voluntary ventilation (MVV) (16%) were not statistically significant. Lesion level was found to be correlated (Spearman Product Moment Correlation) with pulmonary function if a single measure was made (r = 0.55 to 0.73), but emerged as a stronger predictor if the average of several repeated PFTs was correlated with lesion level (r = 0.74 to 0.84). In addition, lesion level was not correlated with the amount of improvement attained during the time period studied. We conclude that the time course of recovery of pulmonary function is variable between individuals with spinal cord injuries and can only be weakly predicted by knowledge of the initial value and the lesion level.

Adolescent↗

PubMed2001

Pulmonary function tests in Parkinson's disease.

Morbidity and mortality are usually caused by respiratory disorders in Parkinson's disease (PD) because of pulmonary functional impairments. The purpose of this study was to determine the effects of PD on ventilatory function and that the use of pulmonary function tests (PFT) may serve as an indicator of PD severity. PFT have been performed in 21 patients with PD (15 non-smoker and six exsmoker with 36.17 +/- 26.54 pack-years of smoking history; mean age 64.67 +/- 10.76 years) and 16 normal age-matched control subjects who never smoked. The clinical disability was indicated by a Hoehn-Yahr (H-Y) scale. MEF25% [maximal flow rate at 25% of remaining forced vital capacity (FVC)] and FEV1 (the volume of air expired during the first second of the FVC) in exsmoker PD group was lower than non-smoker PD group (P < 0.05). The two effort dependent variables' peak expiratory flow (PEF) and the maximal flow rate at 75% of the remaining FVC (MEF75%) percent predicted values were 70.66 +/- 24.15 and 69.05 +/- 24.39 in non-smoker PD group whereas 90.18 +/- 17.24 and 90.00 +/- 18.97% predicted were in control group, respectively (P < 0.05). The maximal voluntary ventilation (MVV) was found to be 52.83 +/- 15.52 and 91.52 +/- 13.80% in PD and control group, respectively (P < 0.0001). MVV was the most effected parameter that was inversely correlated with the PD severity (r=-0.87, P < 0.0001). We concluded that less coordinated and less explosive muscle force has contributed to decrease in PEF and MEF75% values, and MVV decreases in PD as a result of the impaired performance and reduced efficiency during repetitive motor tasks which in part reflects abnormal agonist-antagonist muscle activity. So, spirometric studies may serve as a useful indicator of patients' neurophysiological conditions for the purpose of anticipating and preventing complications because of pulmonary impairment.

Adult↗

PubMed1988

Effect of chronic renal failure on respiratory muscle strength.

In 10 patients with chronic renal failure (CRF), undergoing hemodialysis, we studied respiratory muscle strength and endurance. The data obtained was compared with those acquired from 10 age-, sex-, weight- and height-matched normal volunteers. Maximal static inspiratory pressures (PImax) measured at residual volume and maximal static expiratory pressure (PEmax) measured at total lung capacity were significantly lower in the CRF group, 58.2 +/- (SD)24.9 and 50.8 +/- (SD)24.2% of predicted, respectively (p less than 0.005, p less than 0.01). There was a significant correlation between PImax and PEmax (r = 0.827, p less than 0.001), indicating similar involvement of both inspiratory and expiratory muscle groups. Maximal voluntary ventilation (MVV), although 84.4% of the predicted value in the CRF group, was significantly lower than in the control group, where it was 114% of predicted (p less than 0.001). MVV also correlated significantly with PImax and PEmax (r = 0.764, p less than 0.001 and r = 0.807, p less than 0.001, respectively). All but one CRF patient had elevated erum inorganic phosphorus levels, and a significant correlation was found between the serum inorganic phosphorus levels and PImax and PEmax (r = 0.718, p less than 0.001). These data indicate that there is an impairment of respiratory muscle strength and endurance in patients with CRF which may predispose the patient to respiratory muscle fatigue.

Adult↗

PubMed2006

[Correlations of preoperative pulmonary function tests for esophageal cancer to postoperative acute respiratory distress syndrome].

BACKGROUND & OBJECTIVE: Acute respiratory distress syndrome (ARDS), a serious postoperative complication of esophageal cancer, has a high mortality rate. Preoperative pulmonary function affects treatment project selection and prognosis prediction. The correlation of preoperative pulmonary function of esophageal cancer to postoperative ARDS has seldom been reported. This study was to analyze their correlation to serve for clinical medicine. METHODS: Clinical data of 1 488 esophageal cancer patients, received esophagectomy from 2000 to 2002 in our hospital, were retrospectively reviewed. The correlations of postoperative ARDS to 3 traditional parameters in pulmonary function test, including forced expiratory volume in the first one second (FEV1%), the ratio of FEV1 to forced vital capacity [(FEV1/FVC)%] and maximal voluntary ventilation (MVV%), and other factors, such as age, sex, operation pattern, preoperative cardiac function, early postoperative intensive care, were analyzed. RESULTS: Of the 1,488 patients, 49 suffered postoperative ARDS. The occurrence of ARDS was negatively related to the interaction of FEV1%, (FEV1/FVC)%, MVV% and age (P=0.001, P=0.005, P=0.048). Of the 49 patients suffered severe preoperative lung function damage, 32 received intensive care right after operation, of whom 2 (6.2%) had ARDS; 5 (29.4%) of the remaining 17 had ARDS. Early postoperative intensive care significantly decreased the occurrence of ARDS (P<0.05). CONCLUSIONS: Traditional pulmonary function test have some correlations to postoperative ARDS. Early intensive care is important to prevent ARDS after operation.

Adult↗

PubMed1983

Adverse pulmonary responses to aspirin and acetaminophen in chronic childhood asthma.

Because aspirin (ASA) is often reported to have an adverse effect on pulmonary function in children with chronic asthma, acetaminophen is commonly used as an ASA substitute in these children. To study acetaminophen effects on pulmonary functions, double-blind, oral challenges of ASA (600 mg), acetaminophen (600 mg), or lactose were administered on separate days to 25 chronic asthmatics, ten boys and 15 girls, ranging in age from 8 to 18 years (mean age +/- 1 SD: 12.5 +/- 2.8 years). No patient had a past history of adverse reactions to either drug. Forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEFR), maximal mid-expiratory flow rate (FEF25-75), forced vital capacity (FVC), maximal voluntary ventilation (MVV), and flow volume curves were measured at base line and 1/2, 1, 2, 3, and 4 hours after ingestion of drug or placebo. Persistent decreases from base line FEV1 (greater than 20%) or FEF25-75 (greater than 30%) occurred in four ASA- and two acetaminophen-challenged patients. One ASA-sensitive patient was placebo intolerant; another reacted to acetaminophen. The acetaminophen responses were of less intensity than the ASA responses. Analysis of group mean pulmonary function responses to ASA, acetaminophen, and lactose showed no significant difference among the three agents at any time. Aspirin should be used cautiously in asthmatic children. Acetaminophen appears to be an adequate, although not completely, innocuous ASA substitute.

Acetaminophen↗

PubMed1985

Is the MVV:FEV1 ratio useful for assessing spirometry validity?

The ratio between the maximal voluntary ventilation (MVV) and the forced expiratory volume in one second (FEV1) has been proposed as an indicator of the adequacy of a subject's efforts in disability determinations and other spirometry applications. Data from a large population of industrial workers tested in a university pulmonary function laboratory were examined and a smaller clinical population was used to validate the conclusions. The MVV:FEV1 ratio was not affected to a clinically significant degree by age, degree of functional abnormality, or administration of an aerosolized bronchodilator. The ratio was too variable to be of use in determining whether an individual's results are reliable, but the determination of the average ratio for a large group of subjects may be useful in evaluating the overall performance of a spirometry laboratory.

Adult↗

PubMed1999

Emerging concepts in the evaluation of ventilatory limitation during exercise: the exercise tidal flow-volume loop.

Traditionally, ventilatory limitation (constraint) during exercise has been determined by measuring the ventilatory reserve or how close the minute ventilation (VE) achieved during exercise (i.e., ventilatory demand) approaches the maximal voluntary ventilation (MVV) or some estimate of the MVV (i.e., ventilatory capacity). More recently, it has become clear that rarely is the MVV breathing pattern adopted during exercise and that the VE/MVV relationship tells little about the specific reason(s) for ventilatory constraint. Although it is not a new concept, by measuring the tidal exercise flow-volume (FV) loops (extFVLs) obtained during exercise and plotting them according to a measured end-expiratory lung volume (EELV) within the maximal FV envelope (MFVL), more specific information is provided on the sources (and degree) of ventilatory constraint. This includes the extent of expiratory flow limitation, inspiratory flow reserve, alterations in the regulation of EELV (dynamic hyperinflation), end-inspiratory lung volume relative to total lung capacity (or tidal volume/inspiratory capacity), and a proposed estimate of ventilatory capacity based on the shape of the MFVL and the breathing pattern adopted during exercise. By assessing these types of changes, the degree of ventilatory constraint can be quantified and a more thorough interpretation of the cardiopulmonary exercise response is possible. This review will focus on the potential role of plotting the extFVL within the MFVL for determination of ventilatory constraint during exercise in the clinical setting. Important physiologic concepts, measurements, and limitations obtained from this type of analysis will be defined and discussed.

Exercise↗

PubMed1995

Long-term pulmonary functional outcome of bronchopulmonary dysplasia and premature birth.

Pulmonary function and exercise tolerance were evaluated in late childhood in two groups of prematurely born children: one group with bronchopulmonary dysplasia (BPD) [n = 15; gestational age at birth (GA): 29.6 +/- 2.8 weeks; birth weight (BW): 1,367 +/- 548 g; age at test: 7.9 +/- 0.6 years], and a second group without significant neonatal lung disease [pre-term (PT)] (n = 9; GA: 30.3 +/- 1.7 weeks; BW: 1,440 +/- 376 g; age at test: 7.8 +/- 0.22 years). The results were compared with a control group of children of similar ages and heights, born at term [term born (TB)]. We observed that total lung resistance (RL) was significantly higher in BPD (11 +/- 3 cmH2O/L/s), and in PT (9 +/- 2) than in TB [5 +/- 1; (P < 0.001 and P < 0.05, respectively)]. In BPD RL was higher than in PT (P < 0.05). Dynamic lung compliance (CLdyn) was decreased in BPD (43 +/- 11 mL/cmH2O) and in PT (56 +/- 17) compared with TB (76 +/- 20) (P < 0.001 and P < 0.05), and also in BPD compared with PT (P < 0.05). Forced expiratory volume in 1 second (FEV1) and FEV1/forced vital capacity (FVC) were lower in BPD (1.07 +/- 0.15 L and 72 +/- 7%) than in PT (1.29 +/- 0.23 L, and 80 +/- 7%) (P < 0.05). Exercise tests were performed in six boys with BPD. The ratio between minute ventilation at maximal workload (VEmax) and the predicted value of maximal voluntary ventilation (MVV) was elevated in the six BPD boys tested, compared with five boys of Group 2 and five TB boys (87 +/- 15% vs. 62 +/- 14% and 65 +/- 13%) (P < 0.05). We conclude that: 1) prematurity and BPD is followed by long-term airway obstruction and a mild degree of exercise intolerance and; 2) premature birth without BPD may be followed by a milder degree of airway obstruction in childhood than in infants who developed BPD during the neonatal period.

Analysis of Variance↗

PubMed2006

Pulmonary function in children after a single scuba dive.

This study evaluated the respiratory effects of a single dive in children. Eighteen young divers and 18 controls participated in our study (age range: 9 - 13 years). Volumes and expiratory flow rates were measured 20 minutes before and 10 minutes after one air dive (3 meters, 25 minutes). Before the dive, no differences were noted regarding pulmonary parameters. Ten minutes after the dive, decreases were noted in forced expiratory volume in 1 s (FEV1) and maximal voluntary ventilation (- 8 %, - 5.3 %, respectively; p < 0.01), peak expiratory flow, maximal expiratory flow rates at 50 % of FVC (MEF(50 %)) and MEF(25 %), forced mid-expiratory flow rate (FEF(25 - 75 %)), and FEV1/FVC(- 5.9 %, - 14.3 %, - 21.4 %, - 4.2 %, - 3.5 %, respectively; p < 0.05). The respiratory pattern observed 10 minutes after a single dive to three meters indicated airway narrowing. However, no association between diving experience and lung function was obtained.

Age Factors↗

PubMed1999

Reference values for lung function tests. II. Maximal respiratory pressures and voluntary ventilation.

The strength of the respiratory muscles can be evaluated from static measurements (maximal inspiratory and expiratory pressures, MIP and MEP) or inferred from dynamic maneuvers (maximal voluntary ventilation, MVV). Although these data could be suitable for a number of clinical and research applications, no previous studies have provided reference values for such tests using a healthy, randomly selected sample of the adult Brazilian population. With this main purpose, we prospectively evaluated 100 non-smoking subjects (50 males and 50 females), 20 to 80 years old, selected from more than 8,000 individuals. Gender-specific linear prediction equations for MIP, MEP and MVV were developed by multiple regression analysis: age and, secondarily, anthropometric measurements explained up to 56% of the variability of the dependent variables. The most cited previous studies using either Caucasian or non-Caucasian samples systematically underestimated the observed values of MIP (P < 0.05). Interestingly, the self-reported level of regular physical activity and maximum aerobic power correlates strongly with both respiratory and peripheral muscular strength (knee extensor peak torque) (P < 0.01). Our results, therefore, provide a new frame of reference to evaluate the normalcy of some useful indexes of respiratory muscle strength in Brazilian males and females aged 20 to 80.

Adult↗

PubMed1999

Expiratory flow limitation during exercise in competition cyclists.

In some trained athletes, maximal exercise ventilation is believed to be constrained by expiratory flow limitation (FL). Using the negative expiratory pressure method, we assessed whether FL was reached during a progressive maximal exercise test in 10 male competition cyclists. The cyclists reached an average maximal O2 consumption of 72 ml. kg-1. min-1 (range: 67-82 ml. kg-1. min-1) and ventilation of 147 l/min (range: 122-180 l/min) (88% of preexercise maximal voluntary ventilation in 15 s). In nine subjects, FL was absent at all levels of exercise (i.e., expiratory flow increased with negative expiratory pressure over the entire tidal volume range). One subject, the oldest in the group, exhibited FL during peak exercise. The group end-expiratory lung volume (EELV) decreased during light-to-moderate exercise by 13% (range: 5-33%) of forced vital capacity but increased as maximal exercise was approached. EELV at peak exercise and at rest were not significantly different. The end-inspiratory lung volume increased progressively throughout the exercise test. The conclusions reached are as follows: 1) most well-trained young cyclists do not reach FL even during maximal exercise, and, hence, mechanical ventilatory constraint does not limit their aerobic exercise capacity, and 2) in absence of FL, EELV decreases initially but increases during heavy exercise.

Adolescent↗

PubMed1997

Influence of autonomic neuropathy of different severities on the hypercapnic drive to breathing in diabetic patients.

To investigate the effects of the autonomic nervous system on control of breathing, the neuromuscular (mouth occlusion pressure at 0.1 s after onset of inspiration [P0.1]) and ventilatory (minute ventilation [VE]) response to progressive hyperoxic hypercapnia was assessed in diabetic patients with autonomic dysfunction of different severity. Eighteen diabetics with autonomic neuropathy, nine with parasympathetic damage (DANp), and nine with parasympathetic and sympathetic damage (DANp+s), as indicated by marked postural hypotension, low increment of diastolic BP during sustained handgrip, and lowest resting catecholamine plasma levels, were studied together with a group of 10 diabetic patients without autonomic neuropathy (D) and a group of 10 normal subjects (C). All subjects had pulmonary function tests, including maximal voluntary ventilation and diffusion of carbon monoxide, measurements of respiratory muscle strength as maximal inspiratory mouth pressure (MIP) and maximal expiratory mouth pressure (MEP), and a CO2 rebreathing test (Read's method). Although in the normal range, lung volumes and FEV1 and forced expiratory flows were lower in the DANp and DANp+s groups than in the D and C groups, MIP and MEP were similar among C and diabetic groups, as well as resting P0.1, VE, tidal volume (VT), and respiratory rate (RR). The slope of the linear relationship between P0.1 and end-tidal PCO2 (PETCO2) was higher in DANp+s (0.63+/-0.07 cm H2O/mm Hg) than in C (0.45+/-0.06 cm H2O/mm Hg; p<0.05) and three times greater in DANp+s than in D (0.26+/-0.03 cm H2O/mm Hg; p<0.001) and DANp (0.24+/-0.03 cm H2O/mm Hg; p<0.001), who in turn showed a lower deltaP0.1/deltaPETCO2 than C. The VE increase with increasing PETCO2 was greater in DANp+s (3.70+/-0.85 L/min/mm Hg) than in DANp (2.13+/-0.20 L/min/mm Hg; p<0.05) and D (2.37+/-0.40 L/min/mm Hg; p=0.07), but not significantly higher from that of C (3.17+/-0.36 L/min/mm Hg). No differences were found for deltaVT/deltaPETCO2 among the groups, whereas the deltaRR/deltaPETCO2 relationship was steeper in DANp+s than in DANp (p<0.05) and D (p=0.055). These data reflect a depressed CO2 response both in D and DANp. The presumable decrease of the sympathetic nerve traffic in DANp+s appears to reverse this abnormality. DANp+s, however, exhibit an enhanced CO2 neuromuscular response even in respect to C, suggesting that the sympathetic nervous system might modulate the output of the respiratory centers to hypercapnic stimulus.

Adult↗

PubMed1993

Diaphragmatic fatigue after exercise in healthy human subjects.

The purpose of this study was to determine whether diaphragmatic fatigue occurs after high-intensity constant-load whole-body exercise to volitional exhaustion. Ten sedentary subjects with a maximal oxygen uptake of 2.52 +/- 0.47 L/min were studied. Subjects exercised on a bicycle ergometer at 80% of their maximal working capacity until volitional exhaustion. Minute ventilation during the last minute of exercise was 89.9 +/- 13.6 L/min, which represented 50 +/- 6% of the subjects' 12-s maximal voluntary ventilation. During the last minute of exercise, mean inspiratory esophageal pressure was 18.1 +/- 5.3 cm H2O, which represented only 15 +/- 4% of the subjects' maximal static inspiratory pressure. Bilateral transcutaneous supramaximal phrenic nerve stimulation was performed before and 10, 30, 45 and 60 min after exercise. Twitch diaphragmatic pressure (twitch Pdi) was significantly decreased after exercise in seven of the 10 subjects. For the group as a whole, twitch Pdi fell from 28.9 +/- 3.7 cm H2O during control to 23.9 +/- 5.1 cm H2O at 10 min after exercise (p < 0.005). The fall in twitch Pdi was due to a significant decrease in twitch esophageal pressure from 19.6 +/- 4.3 cm H2O during control to 15.5 +/- 4.9 cm H2O (p < 0.001). Twitch gastric pressure was not significantly different: 8.7 +/- 4.0 cm H2O, compared with 9.2 +/- 3.8 cm H2O during control. Twitch Pdi recovered to 93 +/- 7% of control values at 60 min after exercise. The fall in twitch Pdi after exercise indicates that diaphragmatic fatigue can occur following heavy endurance exercise in sedentary healthy persons.

Adult↗

PubMed2002

Physiological responses to the 6-min walk test in patients with chronic obstructive pulmonary disease.

The 6-min walking test (6MWT) is frequently used to assess functional capacity in chronic cardiopulmonary disorders because of its simplicity. The study examines the physiological responses during encouraged 6MWT in patients with chronic obstructive pulmonary disease. Pulmonary oxygen (O2) uptake (V'O2) was measured in 20 male patients (age 66+/-6 yrs, forced expiratory volume in one second 45+/-14% predicted) during 6MWT and incremental cycling, in random order. O2 tension in arterial blood, carbon dioxide tension in arterial blood and arterial lactate concentration ([La]art) were obtained in the last 10 patients. During the 6MWT, V'O2 showed a plateau after the 3rd min (1.39+/-0.28, 1.42+/-0.31, and 1.40+/-0.30 L x min(-1), 4th, 5th and 6th min, respectively), and minute ventilation (V'E) (42+/-8 L x min(-1)) was 91% maximal voluntary ventilation. No differences were shown between 6MWT (6th min) and peak cycling exercise in V'O2 (1.40+/-0.30 versus 1.41+/-0.28 L x min(-1), respectively), cardiac frequency (126+/-13 versus 130+/-12 beats x min(-1)), or arterial respiratory blood gases. The two tests were significantly different in V'E (42+/-8 versus 47+/-8 L x min(-1), 6MWT versus cycling, respectively), carbon dioxide production (1.30+/-0.31 versus 1.45+/-0.18 L x min(-1)) and [La]art (2.9+/-1.99 versus 5.9+/-1.51 M). The study demonstrates that an encouraged 6-min walking test generates a high but sustainable oxygen uptake. Since the oxygen uptake plateau reflects the integrated response of the system, it may explain the high prognostic value of the 6-min walking test.

Aged↗

PubMed1981

VO2 max during progressive and constant bicycle exercise in sedentary men and women.

VO2 max, as obtained by five cycloergometric test protocols, was studied in 14 normal sedentary subjects: seven women (from 21--35 years) and seven men (from 21--48 years) who carried out four (n = 14) or five (n = 8) of the following exercise programmes: triangular tests, which consist of increasing the load (1) 20 W/min; (2) 30 W/3 min, rectangular tests at constant load; (3) the highest load which the subject could maintain for about 10 min (MSP + 20 W); (4) maximal supported power (MSP) during 20 min; (5) trapezoidal test, consisting of a rectangular exercise of 40 W (10 min), followed test no. 2. Exercises were performed on a cycle ergometer, while VE, VO2, VCO2, f and fH were continuously measured with an open circuit system. In women, the VO2 max (mean +/- SEM) was lower (36.5 +/- 2.1 ml . kg-1 . min-1) than in men (48.7 +/- 3.6 ml . kg-1 . min-1). The highest ventilation rate observed during exercise for the whole group (VE = 101 + 13 l . min-1) was always lower than the maximal voluntary ventilation (MVV = 144 +/- 131 . min-1, p less than 0.001). VO2 max strongly correlated with lean body weight, VC, FEV1, and MVV. In spite of the significant differences between the maximal load level sustained with the first three tests, the VO2 max values were not significantly different. Moreover, there exists an excellent correlation between them. It appears that neither the absolute load sustained in the tests, nor the duration nor intensity of the submaximal load which preceded the maximal level (tests 1, 2, and 5), influence the value of VO2 max.

Adult↗

PubMed1999

Pulmonary function for pectus excavatum at long-term follow-up.

PURPOSE: The aim of this article was to assess whether and to what extent pulmonary function recovered to normal degree postoperatively and to investigate the changes in pulmonary function after surgical correction and the value of surgical correction. METHODS: A total of 27 patients who could be questioned and examined in person at the outpatient department of our hospital were included in this study. Of these patents, 24 were boys and 3 were girls. Their ages ranged from 3 to 16 years (mean, 8.67) at follow-up. The mean age at surgery was 4 years, and mean years of follow-up was 6.8. Pulmonary functional measurements included in vital capacity (VC), total lung capacity (TLC), residual volume (RV), functional residual capacity (FRC), RV-TLC ratio, maximal voluntary ventilation (MVV), force ventilatory capacity (FVC), forced expiratory volume in one second (FEV1), maximal midexpiratory flow curve (MMEF), maximal expiratory flow in 75% vital capacity (V75), maximal expiratory flow in 50% vital capacity (V50), maximal expiratory flow in 25% vital capacity (V25), and breathing reserve ratio (BR). RESULTS: TLC, FRC, MVV, MMEF, V75, and V50 values were not different from the normal values. IVC, FVC, FEV1, and V25 values were decreased significantly compared with the normal values. The RV and RV-TLC were high in 87.5% cases. CONCLUSIONS: Preoperative symptoms obviously improved after operation. There was little airway obstruction in the patients postoperatively. The patients with pectus excavatum should be operated on as soon as possible.

Adolescent↗