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PubMed1987

Vital capacity and airflow measured from partial flow-volume curves during 5 degrees head-down tilt.

Ten healthy young males were subjected to 7 min of 5 degrees head-down tilt, during which their forced vital capacity, peak flow rate (from complete flow-volume curves), and MEF 40% and 25% (airflows when 40% and 25% of the vital capacity remains in the lungs) from the partial curves were measured. The values of these variables and the heart rate and blood pressure were not significantly different from the values obtained in the supine position. In view of these findings it is concluded that the increase in the intra-thoracic blood volume, known to occur with 5 degrees head-down tilt used as a model for simulating weightlessness, does not embarrass respiratory mechanics.

Adult↗
PubMed2003

Comparison of maximal midexpiratory flow rate and forced expiratory flow at 50% of vital capacity in children.

BACKGROUND: The mid-portion of the maximal expiratory flow-volume (MEFV) curve is often described by values of the mean forced expired flow as lung volume decreases from 75% to 25% of vital capacity (ie, forced expiratory flow, midexpiratory phase [FEF(25-75)]). It is common practice to report also forced expired flow at 50% of vital capacity (FEF(50)). STUDY OBJECTIVE: To investigate whether FEF(50) and FEF(25-75) are highly correlated or whether the difference between them reflects a degree of airways obstruction. Also, we wanted to investigate the correlation between the two in cases of irregularly shaped MEFV curves (ie, "saw-toothing"). DESIGN: Analysis of the correlation between FEF(50) and FEF(25-75) in a single determination. We assessed the relationship between the FEF(50)/FEF(25-75) ratio and the degree of airways obstruction, as reflected by other traditional parameters such as FEV(1), FEV(1)/FVC ratio, and specific airway conductance (SGaw). PATIENTS: There were 1,350 forced expiratory maneuvers performed by children with a broad range of pulmonary abnormalities. RESULTS: FEF(50) correlated with FEF(25-75) as follows: FEF(50) (L/s) = 0.041 + 1.136*FEF(25-75)(L/s); r(2) = 0.956; standard error of the estimate = 0.013; p < 0.0001. The FEF(50)/FEF(25-75) ratio remained stable and did not correlate with FEV(1) (r = 0.12), FEV(1)/FVC ratio (r = 0.11), or SGaw (r = 0.02; difference not significant). The correlation between FEF(25-75) and FEF(50) was similar for both the smooth curve (r = 0.97) and the irregular curve (r = 0.96). CONCLUSIONS: Although not identical, FEF(25-75) and FEF(50) are highly correlated, and the ratio of the two is fairly constant. Therefore, the practice of reporting both of them is unnecessary. We suggest that it is reasonable to prefer FEF(50).

Child↗
PubMed1990

Preoxygenation in parturients: a comparison of 4, 6 and 8 vital capacity breaths to 5 minutes of tidal volume breathing.

We compared the difference in denitrogenation (by intermittent measurement of arterial tension, PaO2) in 45 parturients at term when preoxygenated with 4, 6 or 8 rapid vital capacity breaths and 5 minutes of tidal volume breathing. Oxygen, at 8 litres min-1, was delivered through a facemask via a circle absorber with a 2 litre reservoir bag. Higher PaO2 was produced with 5 minutes of tidal volume breathing. This differed significantly from the PaO2 produced by 4, 6 or 8 rapid vital capacity breaths (p less than 0.01).

Adult↗
PubMed2007

Single breath vital capacity induction of anesthesia with 8% sevoflurane versus intravenous propofol for laryngeal tube insertion in adults.

OBJECTIVE: To compare the conditions for laryngeal tube airway insertion obtained by the inhalation of 8% sevoflurane using a vital capacity breath (VCB) technique with propofol intravenous induction. METHODS: We carried out a prospective, randomized, single blind study at King Abdullah University Hospital, Irbid, Jordan from September 2005 to April 2006. Involved in this study were 80 adult (ASA physical status I and II) patients aged 26-70 years undergoing elective surgery under general anesthesia. The patients were randomized into 2 groups. An independent observer noted the time to loss of consciousness, the presence of adverse events, time to successful laryngeal tube placement and the number of attempts needed until a successful laryngeal tube insertion. RESULTS: With the single VCB method, sevoflurane produced a loss of consciousness faster than propofol did (51.6 +/- 4.4 versus 59.7 +/- 4.9 seconds, p<0.001). The insertion of laryngeal tube was faster in the propofol group (77.2 +/- 20.2 versus 122.2 +/- 33.3 seconds, p<0.001) and required fewer attempts (1.2 +/- 0.4 versus 1.6 +/- 0.7, p<0.02). The overall incidence of complications during the induction of anesthesia as well as during the laryngeal tube insertion, especially apnea (42% versus 0%; p<0.001), was more frequent in the propofol group (82.5% versus 27.5%; p<0.001). CONCLUSION: We conclude that vital capacity breath induction with sevoflurane produces a faster loss of consciousness and fewer side effects than propofol and efficient for laryngeal tube insertion, but takes slightly longer than propofol due to the prolonged jaw tightness.

Adult↗
PubMed2003

Vital capacity induction with 8% sevoflurane and N2o causes cerebral hyperemia.

PURPOSE: Little is known about the influence of high-dose sevoflurane on cerebral volume. We evaluated induction time and cerebral blood volume with 8% sevoflurane using the "vital capacity induction" technique. METHODS: Thirty-four patients were randomly allocated into three groups. Group P received 2.0 mg x kg(-1) of propofol i.v. and inhalation of 67% N2o/O2, whereas group S5 and group S8 received inhalation of primed 5% and 8% sevoflurane in 67% N2O/O2, respectively. Induction time was measured as the time from the start of inhalation, or from the end of injection, until loss of eyelash reflex. Near-infrared spectroscopy and bispectral index (BIS) were monitored continuously until 3 min after tracheal intubation. RESULTS: Induction time was less in group S8 (17.3 +/- 6.4s, mean +/- SD) than in groups P (25.7 +/- 8.2s) and S5 (33.0 +/- 16.8s). There was a significant increase in cerebral blood volume after intubation in group S8, as suggested by higher cerebral oxyhemoglobin and total hemoglobin levels. There were no differences in BIS scores among the groups during the study period. CONCLUSION: Vital capacity inhalation of 8% sevoflurane produces a faster loss of eyelash reflex than does 5% sevoflurane or propofol, but increases cerebral blood volume.

Anesthesia, General↗
PubMed1980

Vital capacity, exercise performance, and blood gases at altitude as related to age.

Vital capacity (VC) rarely may decrease 35-60% in healthy mountain climbers associated with high-altitude pulmonary edema (HAPE). In the age range 58-71 yr, five of six men during a week or more on White Mt. in 1962 had decreases in VC from 20 to 32% without frank symptoms of HAPE, Dill, one of the five, had decreases in VC again on White Mt. in 1977 and 1978. Yet none of 11 young climbers on White Mt. studied by Hultgren (personal communication) had a significant decrease in VC. Dill's arterial O2 saturation at age 87 at 485 Torr was about 79% in rest and 74% when VO2 was 0.74 ml/min.kg. His aerobic capacity at age 87 yr was 18 ml/min.kg at 695 Torr and 15 at 485 Torr.

Adult↗
PubMed1990

Can a single equation be used to predict the vital capacity of boys both before and during puberty?

Good theoretical values for vital capacity (VCt) can be used to calculate a VC/VCt ratio which remains constant for a given individual subject throughout different growth periods. This longitudinal study on 27 boys was performed in order to determine whether a single equation was accurate throughout the growth of boys. The mean values of VC/VCt were also compared for the beginning and end of the prepubertal period in 57 boys and between the beginning and end of puberty in 40 boys. VCt was calculated from five reference equations using data from boys with average age 8-16 yrs, and from two equations using data specific to children and adolescents. The mean VC/VCt ratio was found to fall between the beginning and end of the prepubertal period and to increase very significantly between the beginning and end of the pubertal period when the reference equation used had been calculated using data from populations containing both pubertal and prepubertal subjects. When the equations established from adolescents were used, VC/VCt fell slightly between the beginning and end of the pubertal period. We conclude that data for children and adolescents should be treated separately when establishing reference values for VC.

Adolescent↗
PubMed2005

Respiratory muscle strength may explain hypoxia-induced decrease in vital capacity.

PURPOSE: High altitude exposure has consistently been reported to decrease forced vital capacity (FVC), but the mechanisms accounting for this observation remain incompletely understood. We investigated the possible contribution of a hypoxia-related decrease in respiratory muscle strength. METHODS: Maximal inspiratory and expiratory pressures (MIP and MEP), sniff nasal inspiratory pressure (SNIP), FVC, peak expiratory flow rate (PEF), and forced expiratory volume in 1 s (FEV1) were measured in 15 healthy subjects before and after 1, 6, and 12 h of exposure to an equivalent altitude of 4267 m in a hypobaric chamber. RESULTS: Hypoxia was associated with a progressive decrease in FVC (5.59 +/- 0.24 to 5.24 +/- 0.26 L, mean +/- SEM, P < 0.001), MIP (130 +/- 10 to 114 +/- 8 cm H2O, P < 0.01), MEP (201 +/- 12 to 171 +/- 11 cm H2O, P < 0.001), and SNIP (125 +/- 7 to 98 +/- 7 cm H2O, P < 0.001). MIP, MEP, and SNIP were strongly correlated to FVC (r ranging from 0.77 to 0.92). FEV1 didn't change, and PEF increased less than predicted by the reduction in air density (11-20% of sea-level value compared with 32% predicted). CONCLUSION: We conclude that a decrease in respiratory muscle strength may contribute to the decrease in FVC observed at high altitude.

Adult↗
PubMed1997

Major genetic effect on forced vital capacity: the Humboldt Family Study.

Familial correlation and segregation analyses of forced vital capacity (FVC) were performed on data from 309 nuclear families with 1,045 individuals in the town of Humboldt, Saskatchewan, in 1993. FVC was preadjusted for age, height, and weight in four separate groups (mothers, fathers, daughters, and sons). Residual FVC was standardized within the four groups. Class D regressive model was first used to examine the familial resemblance of FVC without a major gene. While mother-father correlation was not significantly different from zero and mother-sibling and father-sibling correlations were not significantly different from each other, sibling-sibling correlation was greater than parent-sibling correlation. Segregation analysis for all 309 families indicated that both the Mendelian and no-parent-offspring-transmission models fitted the data as did the general model with arbitrary transmission probabilities. Likelihoods under the Mendelian model (LMendelian) and the environmental model (Lenvironmental) were calculated. Based on the value of In(LMendelian/Lenvironmental), 309 families were divided into two groups: 196 families with the value of In(LMendelian/Lenvironmental) greater than zero (group I) and 113 families with the value In(LMendelian/Lenvironmental) less than zero (group II). The Mendelian transmission model without familial correlations was the most parsimonious model for the families in group I. For group II, there were two best models of choice: 1) no-parent-offspring-transmission model with possible heterogeneity plus familial correlations [Akaike's information criterion (AIC) = 1,213.76] and 2) Mendelian transmission plus sibling-sibling correlation model (AIC = 1,202.36). The results suggest there are major genetic mechanisms in FVC with possible heterogeneity.

Adolescent↗
PubMed1987

Variability and reversibility of the slow and forced vital capacity in chronic airflow obstruction.

The variability of the forced (FVC) and slow vital capacity (SVC) manoeuvres were compared in 33 adult patients with chronic airflow obstruction. The reversibility of the two manoeuvres to nebulized salbutamol were compared in 18 of the patients. Both manoeuvres had equally small variances both before and after bronchodilator. The degree of reversibility of the FVC was however significantly greater (P less than 0.05) than the SVC. Although both measurements are equally variable, the FVC has a greater capacity for reversibility, which may have clinical significance.

Albuterol↗
PubMed2000

Can peak expiratory flow be measured accurately during a forced vital capacity manoeuvre?

Spirometry and peak flow measurements traditionally depend on different forced expiratory manoeuvres and have usually been performed on separate, dedicated equipment. As spirometry becomes more widely used in primary care settings, the authors wished to determine whether there was a systematic difference between peak expiratory flow (PEF) derived from a short sharp exhalation (PEF manoeuvre) and from a full forced vital capacity (FVC) manoeuvre, using the same turbine spirometer (Microloop, Micro Medical, Kent, UK). Eighty children (38 with current asthma) aged 7-16 yrs were asked to perform 2 blocks of PEF and FVC manoeuvres, the order being randomly assigned. PEF obtained from a peak flow manoeuvre (PEFPF) was significantly greater than that from a forced vital capacity manoeuvre (PEFVC) in both healthy (group mean difference 20 L x min(-1); p<0.001) and asthmatic children (group mean difference 9 L.min(-1); p<0.004). For clinical purposes, a mean difference of about 3% for children with asthma is of no practical significance, and peak expiratory flow data can usefully be obtained during spirometric recordings.

Adolescent↗
PubMed2001

Expiratory and inspiratory forced vital capacity and one-second forced volume in asymptomatic never-smokers in Norway.

The objectives of this study were to examine within and between individual variation detected during forced expiratory (FE) and forced inspiratory (FI) manoeuvers in a general population and to investigate the dependence of these variables on age, body size, and gender. A random sample of asymptomatic never smokers who had never been exposed occupationally to quartz or asbestos and who were living on the south-western coast of Norway were examined by spirometry; 81% of the individuals invited to attend did so. Of the 488 subjects between 18 and 73 years of age, 98% contributed three acceptable recordings for forced expiratory vital capacity (FVC) and one-second forced expiratory volume (FEV1), 94% contributed three acceptable recordings for forced inspiratory vital capacity (FIVC) and 85% contributed three acceptable recordings for one-second forced inspiratory volume (FIV(1)). The within-subject variation increased with body height and was considerably larger for FIV(1) than for FVC, FEV(1) or FIVC. A four-parameter model of pulmonary function measurement divided by height squared, including a gender term and a linear and quadratic term of age, fit the median of the observed values well. The residuals had a close-to-normal distribution, and the fifth-percentile values were estimated as the lower limit of normal. The peak value of dynamic lung volumes was observed into the middle of the fourth decade of life, and the decline thereafter did not differ greatly between the genders or among the different indices. The forced inspiratory volumes are the first reported in any reference population.

Adolescent↗
PubMed2000

Smooth reference equations for slow vital capacity and flow-volume curve indexes.

We derived reference values for slow vital capacity (VC) and flow-volume curve indexes (FVC, FEV(1), and flows) from the 1,185 tracings provided by 1,039 "normal" subjects who participated in one or both cross-sectional surveys of the Po River Delta study in 1980-1982 and in 1988-1991. Definition of "normal" was based on negative answers to questions on respiratory symptoms/diseases or recent infections, current/past tobacco smoking, and work exposure to noxious agents. Reference equations were derived separately by sex as linear regressions of body mass index (BMI = weight/height(2)), BMI-squared, height, height-squared, and age. Age entered all the models by natural cubic splines using two break points, except for the ratios FEV(1)/VC and FEV(1)/FVC. Random effects models were applied to adjust for the potential intrasubject correlation. BMI, along with height and age, appeared to be an important predictor, which was significantly associated with VC, FEV(1), FVC, FEV(1)/FVC, and PEF in both sexes, and with FEV(1)/VC and FEF(25-75) in females. Natural cubic splines provided smooth reference equation curves (no "jumps" or "angled points") over the entire age span, differently from the conventional reference equations. Thus, we recommend the use of smooth continuous equations for predicting lung function indexes, along with the inclusion of BMI in the equations.

Adolescent↗
PubMed1990

Preoxygenation of patients for coronary artery bypass grafting: vital capacity versus tidal breathing.

Arterial oxygenation, as measured by serial arterial blood gases (ABGs) and in vivo polarographic PaO2 during the rapid sequence induction of general endotracheal anesthesia, was evaluated in 20 ASA physical class IV subjects undergoing elective coronary artery bypass grafting (CABG). Subjects received a narcotic premedication 30-60 minutes prior to arrival in the operating room. Subjects in Group I (n = 10) were preoxygenated with 3 minutes of tidal breathing, while Group II (n = 10) subjects took four vital capacity breaths (VCB) within 30 seconds. Manual ventilation was withheld after the period of preoxygenation (the mean duration of apnea was 121.25 seconds). The mean PaO2 rose from 69.40 mmHg to 323.80 mmHg after preoxygenation in Group I and from 73.70 mmHg to 359.10 mmHg in Group II. After tracheal intubation, the mean PaO2 fell to 275.70 mmHg in Group I compared with 277.20 mmHg in Group II. There was no significant difference (p greater than 0.05) between the two methods of preoxygenation in their ability to increase arterial oxygen. In conclusion, vital capacity breathing is as effective as 3 minutes of tidal breathing in elevating the PaO2 in subjects with significant coronary artery disease prior to a rapid sequence induction.

Aged↗
PubMed1975

Vital capacity and one-second forced expiratory volume in Australian male factory workers.

The vital capacity (VC) and one-second forced expiratory volume (FEV1) of 482 men were measured and corrected for temperature but not pressure. The relationship between both VC and FEV1 and height and age was examined and found to be linear. In using these relationships for significance testing the 95% confidence limit is 1.65 standard deviations below the predicted value. Our results are expressed in graphical form to facilitate interpolation and will thus be of use to the clinical practitioner in Australia. Neither weight nor smoking habit was found to influence the relationship of VC or FEV1 with age or height.

Adult↗
PubMed1978

[Longitudinal study of vital capacity during the growth of 69 poliomyelitics (author's transl)].

A longitudinal study of vital capacity (VC) during the growth of 69 children with poliomyelitis was made starting shortly after the end of the period of muscular recovery until they attained 17 years. VC was compared with two theoretical values (VCT). The beginning of puberty was determined by the acceleration of growth of total height and the appearance of pubic hair. Statistical analysis of VC/VCT between the beginning and the end of the study reveals that intercostal paralysis, costal deformities, dorsal scoliosis over 30 degrees and atelectasis were significantly more frequent among the 46 children with unfavourable evolution than among the 23 children with favourable evolution. Comparison of the VC/VCT means at different periods of growth reveals that the growth of VC in poliomyelitics does not undergo the same acceleration as that of height during the two years after the beginning of puberty. In normal subjects, this phenomen has not been clearly seen in cross sectional studies which do not take into account the stage of puberty.

Adolescent↗
PubMed2006

Scleroderma lung: initial forced vital capacity as predictor of pulmonary function decline.

OBJECTIVE: To determine the ability of initial forced vital capacity (FVC) of patients with scleroderma to predict subsequent pulmonary function deterioration. METHODS: Data on 78 patients with scleroderma were retrospectively collected and analyzed. FVC (percent predicted), diffusing capacity for carbon monoxide (percent predicted), and various clinical and laboratory parameters were recorded. Pulmonary function decline (outcome) was defined as at least a 15-point sustained decrease in FVC (percent predicted). Kaplan-Meier analyses were performed separately for 60 patients initially assessed within the first 3 years from disease onset (group A) and 16 patients whose FVC values in the fourth or fifth year from disease onset were ascribed as baseline measurements (group B). RESULTS: Based on baseline FVC, patients in each group were categorized into those with normal FVC (> or =80% predicted) and those with decreased FVC (<80% predicted). In group A, the percent-predicted FVC of 89% of patients with normal initial FVC and of 75% of patients with reduced baseline FVC did not decrease by > or =15 points at 5 years (log rank P = 0.04). Four patients with decreased baseline FVC developed respiratory failure (FVC <50% predicted) versus none with normal initial FVC. Analysis of group B showed no difference between patients with normal baseline FVC and those with decreased FVC in the ability to further predict pulmonary function decline (log rank P = 0.13). Clinical and laboratory parameters (age, male sex, baseline diffusion capacity, anti-topoisomerase I, or duration of Raynaud's phenomenon preceding skin manifestations) were not associated with pulmonary function decline. CONCLUSION: Measured within the first 3 years from disease onset, baseline FVC (percent predicted) may predict deterioration of pulmonary function in patients with scleroderma. Patients with normal pulmonary function at initial assessment are at low risk to develop considerable impairment of pulmonary function.

Adult↗