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PubMed2002

Effects of inspiratory muscle training upon recovery time during high intensity, repetitive sprint activity.

The present study examined the influence of specific inspiratory muscle training (IMT) upon recovery time during repetitive sprint activity, as well as the physiological and perceptual responses to fixed intensity shuttle running. Using a double-blind placebo-controlled design, 24 male repetitive sprint athletes were assigned randomly to either an IMT (n = 12) or placebo (n = 12) group. The self-selected recovery time during a repetitive sprint test and the physiological response to submaximal endurance exercise were determined. Following completion of baseline and pre-intervention measures, the IMT group performed 30 inspiratory efforts twice daily against a resistance equivalent to 50 % maximum inspiratory mouth pressure (MIP) for 6 wk. The placebo group performed 60 breaths once daily, for 6 wk, at a resistance equivalent to 15 % MIP, a load known to elicit negligible changes in respiratory muscle function. The IMT group improved total recovery time during the repetitive sprint test by 6.2 +/- 1.1 % (mean +/- SEM) above the changes noted for the placebo group (p = 0.006). Blood lactate and perceptual responses to submaximal exercise were also significantly attenuated following IMT (p </= 0.01). These data support existing evidence that specific IMT attenuates the blood lactate and perceptual responses to submaximal endurance exercise. In addition, the present study provides new evidence that IMT improves recovery time during high intensity, intermittent exercise in repetitive sprint athletes.

Adult↗
PubMed2004

[Does nCPAP-therapy change the lung function of patients with obstructive sleep apnea syndrome?].

BACKGROUND: nCPAP-therapy is standard for patients with obstructive sleep apnea syndrome (OSAS). This study investigated, if nCPAP changed the patients lung function. PATIENTS AND METHODS: Lung function of 228 OSAS patients without co-prevalent lung disease, who received nCPAP for the first time, was examined (whole body plethysmography, spirometry, and blood gas analysis). After 1, 2, and 3 years the results of the re-examined patients were compared with their individual starting results. RESULTS: The results of the patients in the basic and in the follow-up examinations was within standard range. During reexamination, an improvement of inspiratory vital capacity was registered repetitively, especially in smokers. On the other hand, MEF 50 decreased within the first two years and FEV (1) %VC, but not FEV (1), decreased after 2 and 3 years of reexamination. CONCLUSIONS: Neither obstructive nor restrictive lung diseases were diagnosed under nCPAP-therapy within three years. This study with a retrospective design showed significant improvements of vital capacity (VC) in patients with OSAS, especially in smokers, under nCPAP-therapy. This increase can be explained by an effect of practice in the examination and by recruitment of formerly hypoventilated lung areas. As MEF 50 and FEV (1) %VC depend on VC, the decrease of both parameters may be caused by the increase of VC. In summary, nCPAP did not cause negative effects of lung function in the investigated patients over a period of 3 years.

Continuous Positive Airway Pressure↗
PubMed1983

The assessment of cardiopulmonary function in thoracic surgery.

Cardiopulmonary function is a determinant of the utmost importance in thoracic surgery. A large battery of tests is available, however, only a relatively limited part of it is obligatory. The essential procedures include testing of global ventilation (inspiratory vital capacity, FEV1), relation of lung volumes (residual volume) and regional quantitation of perfusion (scan). Other costly and invasive tests can be regarded as complementary. This is true in planned lung resection for cancer, where the indication for surgery is of vital importance. Other types of thoracic surgery need a more precise evaluation of risk factors balanced against the expected general improvement of cardiopulmonary function, as in cardiac surgery, decortication, and resection of bullae. But since thoracic surgery is practised mainly for the purpose of lung resection with ensuing loss of function, major attention is paid to this field in order to avoid inconclusive but costly testing, and to discuss indication and use of involved technique in high-risk patients.

Blood Gas Analysis↗
PubMed1998

Effect of a nasal dilatator on nasal patency during normal and forced nasal breathing.

A nasal dilatator contains two elastic strips, which provide the dilatator with a spring action. The aimed function of the nasal dilatator is to slightly open the nares and hereby facilitate nasal breathing. The aim of this study was to evaluate the effect of a nasal dilatator by measuring nasal airway resistance during normal breathing and nasal forced expiratory and inspiratory flows and volumes with and without use of the nasal dilatator. Nasal resistance was measured with a whole body plethysmograph; maximal expiratory and inspiratory flow-volume curves were obtained with a pneumotachometer. These measurements were performed in ten healthy volunteers. No significant difference was found between nasal resistance with and without the nasal dilatator. However, values for forced inspiratory volume in 1 s (FIV 1) with the nasal dilatator, proved to be significantly higher (p=0.045,paired t-test) than values obtained without the nasal dilatator; mean improvement was 0.26 L (sd = 0.36). No significant improvement in peak inspiratory flow (PIF) was found, as was the case for the other flows and volumes. It is concluded that the nasal dilatator causes no appreciable improvement of nasal patency during normal breathing. In view of the fact that FIV 1 values increased significantly, we believe that the nasal dilatator prevents collapse of the external nares during forced inspiration. A beneficial effect during exercise when ventilation is increased is however doubtful because in that situation most volunteers switch to oronasal breathing already at submaximal exercise.

Adult↗
PubMed1997

Inspiratory muscle fatigue following running to volitional fatigue: the influence of baseline strength.

Respiratory muscle fatigue has been demonstrated following short-term exercise to volitional fatigue, as well as following prolonged submaximal exercise. There is some suggestion that the respiratory muscles of 'athletic' individuals have superior strength and greater fatigue resistance but it is not known whether inspiratory muscle strength influences fatigueability of the inspiratory muscles. The present study examined this question in 24 moderately trained young men. Inspiratory muscle strength was measured at residual volume using a hand held Mouth Pressure Meter before and after an incremental, multistage shuttle run to volitional fatigue. Following the run, there was a significant fall in inspiratory mouth pressures (-10.5 +/- SD 8.2%; p < 0.001 Pre- vs Post Pipeak). The subjects with the weakest inspiratory muscles exhibited significantly greater fatigue than those with the strongest (-17.0 +/- SD 7.8% c.f. 6.8 +/- SD 4.4% for the 25th and 75th percentiles respectively p < 0.01). These data support existing evidence that the respiratory muscles fatigue following high intensity exercise. In addition, they provide new evidence that this phenomenon occurs in moderately trained young men and that the severity of the fatigue is related to the baseline strength of the inspiratory muscles.

Adult↗
PubMedDate not supplied

Control of inspiratory timing in newborn infants.

In order to determine if inspiratory time in preterm infants was influenced by lung volume, two studies were carried out. In the first investigation, carbon dioxide was used to stimulate tidal volume to a level three to six times normal. The anticipated decrease in inspiratory time at increased tidal volumes was not found. These preterm infants behaved in a similar fashion to vagotomized animals studied in the same way by Clark and von Euler. In the second investigation, Hering-Breuer activity was measured in relation to lung volume changes occurring with growth, measured in a body plethysmograph. Although thoracic gas volume correlated well with age and weight, inspiratory slowing with airway occlusion was found to be independent of both age and lung volume. These investigations suggest that neurologic factors have a significant influence on the inspiratory time in newborn human infants.

Airway Obstruction↗
PubMedDate not supplied

Characteristics associated with successful weaning in ventilator-dependent preterm infants.

Eighteen ventilator-dependent preterm infants with hyaline membrane disease were studied for 24 hours before and after an attempt at extubation. All were treated with theophylline prior to weaning and achieved average levels of 8.9 +/- 1.7 micrograms/ml (49 +/- 9 mumol/liter) in 13 successfully weaned infants and 8.4 +/- 1.1 micrograms/ml (47 +/- 6 mumol/liter) in 5 infants not extubated, p > 0.05. Infants successfully weaned were significantly (p < 0.01) older, more mature (29 +/- 1 versus 26 +/- 2 weeks' gestational age) and heavier (1107 +/- 236 versus 1016 +/- 256 gm) than infants not successfully extubated. Infants successfully weaned differed only in developing a greater maximal inspiratory force (33.8 +/- 12.3 versus 23.3 +/- 15.0 cm H2O) and higher compliance (1.1 +/- 0.3 versus 0.7 +/- 0.3) during the preweaning treatment period. These results indicate that maturity and size play a significant role in the ability to wean a preterm infant from the ventilator successfully, that maximal inspiratory force and compliance are higher in preterm infants who can be successfully extubated, and that methylxanthines do not uniformly improve pulmonary function in all potentially extubatable preterm infants.

Humans↗
PubMed2000

Onset of action of intranasal budesonide (Rhinocort aqua) in seasonal allergic rhinitis studied in a controlled exposure model.

BACKGROUND: Intranasal budesonide aqueous nasal spray (BANS) is recognized as an efficacious treatment for seasonal allergic rhinitis (SAR), but the time to onset of action is not known. OBJECTIVE: The primary objective was to evaluate the time at which the onset of action of BANS in the symptomatic relief of seasonal allergic rhinitis becomes evident within 12 hours after a single dose in a controlled ragweed pollen exposure setting. METHODS: The study was of a double-blind, randomized, parallel-group design, testing BANS (64 microgram and 256 microgram) and placebo on ragweed-sensitive subjects with symptoms for at least 1 year by using a controlled pollen challenge system (Environmental Exposure Unit). The efficacy variables were the combined nasal score (the sum of blocked nose, runny nose, and sneezing-itchy nose), individual nasal symptoms, overall evaluation of treatment efficacy reported by participants on diaries, and peak nasal inspiratory flow (PNIF). RESULTS: A total of 217 participants were treated with BANS or placebo. At 7 to 12 hours, BANS was better than placebo in reducing combined nasal and blocked nose symptoms. For PNIF, the time to onset of action was shortest for 256 microgram of BANS relative to placebo (3 hours, P =.003). BANS 64 microgram was better than placebo in reducing the individual scores of blocked nose, runny nose, and sneezing-itchy nose from 3 to 5 hours after administration. Treatment efficacy was higher for those receiving BANS compared with placebo starting at 5 hours. All treatments were well tolerated, and no specific adverse events occurred. CONCLUSIONS: The onset of action of intranasal BANS was 7 hours according to combined nasal and blocked nose symptom scores. Evidence of earlier response was observed at 3 hours for runny nose and PNIF.

Administration, Intranasal↗
PubMedDate not supplied

A pilot study to investigate any relationship between sustained maximal inspiratory pressure and extubation outcome.

OBJECTIVE: To establish whether any relationship exists between extubation outcome and sustained maximal inspiratory pressures (SMIP). DESIGN AND SETTING: Prospective clinical study in the 7-bed general intensive care unit of a university hospital. SUBJECTS: Twenty-seven intubated adults who were deemed ready for extubation were enrolled. MEASUREMENTS: Standard respiratory parameters and inspiratory muscle function data (ie, SMIP and peak maximal inspiratory pressures [MIP]) were recorded before extubation. RESULTS: SMIP was found to be significantly greater in those who were successfully extubated than in those who underwent a failed extubation (P <.01). Receiver operating characteristic curves for SMIP data indicated that a cutoff point of 57.5 pressure time units would give a sensitivity and specificity of 1.0 for extubation outcome prediction. Peak MIP was also significantly greater in those successfully extubated (P =.04); a cutoff point of 17.5 cm H(2)O gave a sensitivity of 1.0 and a specificity of 0.5. CONCLUSIONS: In this study, peak MIP was not specific enough to be clinically useful as a predictor of extubation outcome. SMIP was associated with extubation outcome with equally high sensitivity and specificity and may therefore have a role in outcome prediction.

Aged↗
PubMed2003

Inspiratory pressure threshold training for upper airway limitation: a case of bilateral abductor vocal fold paralysis.

A single subject design was used to determine if pressure threshold training strengthens the inspiratory muscles in a subject with a limited glottal airway as well as diminish dyspnea and improve parameters of speech. The subject was a 19-year-old woman whose glottal airway was limited due to bilateral abductor vocal fold paralysis following a thyroidectomy. A 5-week inspiratory muscle strength-training program was implemented using a pressure-threshold trainer to strengthen the inspiratory muscles with the intent of enabling the generation of higher inspiratory pressures. The pressure threshold on the trainer was set at 75% of the subject's maximum inspiratory pressure (MIP). The subject was required to generate sufficient inspiratory pressure to bring air through the trainer during an inspiratory maneuver. MIP was the dependent variable used as an indication of inspiratory muscle strength. MIP increased by 47% following the training program. Maximal minute ventilation and oxygen uptake increased posttraining. Dyspnea during exercise and speech decreased as reported by the subject. Total reading duration and pause duration demonstrated a declining trend during connected speech. The results indicated that inspiratory muscle training using a pressure threshold device improves functional tasks such as exercise and speech in a subject with upper airway limitation.

Adult↗
PubMed2004

Clinical relevance of nasal polyps in individuals recruited from a general population-based study.

OBJECTIVE: To compare the clinical presentations of individuals with nasal polyps detected by endoscopy in a general population sample with those of patients with nasal polyp disease seeking medical attention. MATERIAL AND METHODS: A total of 38 individuals with nasal polyps from a population-based sample were compared with 38 matched controls and a third group consisting of 44 patients who presented to an outpatient clinic with symptoms and diagnosed nasal polyps Upper and lower airway symptoms were registered. Polyp size, peak nasal inspiratory flow (PNIF), olfactory function and health-related quality of life were measured. RESULTS: Compared with the individuals with nasal polyps in the population sample, patients actively seeking medical care for nasal polyposis experienced more symptoms of nasal blockage and an impaired sense of smell, and had more extensive polyps and reduced PNIF. There were equal frequencies of asthma symptoms in these two groups. Compared with the controls, the individuals with nasal polyps in the population sample had a greater frequency of asthma symptoms and aspirin intolerance and also experienced an impaired sense of smell. CONCLUSION: Nasal polyps alone, as seen occasionally, are indicative of airway disease involving the upper and lower respiratory tracts.

Adult↗
PubMedDate not supplied

Effect of respirator inspiratory resistance level on constant load treadmill work performance.

Respirator inspiratory resistance can affect performance times, especially when the experiment is optimized to elicit respiratory stress. Twelve subjects performed on a treadmill at constant speeds and grades chosen to result in performance times of 5-15 min. Six levels of inspiratory resistance were used, ranging from 0.78 to 7.64 cm H2O.sec/L. The results showed that performance times decrease linearly with resistance level, and no threshold resistance value is apparent. Inspiratory resistance also induces hypoventilation, with lower minute volumes and lower oxygen consumption values at higher resistances. These trends are also linear. From these results, there is no value for inspiratory resistance that can be given as a design goal. Other parameters such as weight and space may dictate filter resistance values, and these, in turn, will lead to determined performance degradations.

Adolescent↗
PubMedDate not supplied

Nasal inhalation challenge studies with sidestream tobacco smoke.

Environmental tobacco smoke (ETS) exposure is associated with rhinitis symptoms (i.e., runny nose and congestion) in some people. In an effort to better understand these symptoms, we recruited 18 historically ETS-sensitive subjects from the community and exposed them for 15 min to clean air and for 15 min to sidestream tobacco smoke (STS, 45 ppm carbon monoxide). Symptoms were recorded (0 = absent, 5 = severe), and posterior rhinomanometry was performed. There were significant changes in rhinitis symptoms (1.3 +/- 0.4 pre- versus 6.1 +/- 0.5 post-STS, p less than .05); nasal airway resistance (2.86 +/- 0.2 pre- versus 4.49 +/- 0.6 post-STS, p less than .05), and maximum inspiratory flow (2.74 +/- 0.3 pre- versus 2.14 +/- 0.3 post-STS, p less than .05). A spectrum of individual responsiveness to ETS was observed, and nasal resistance increased from 0% to 265%. Increased nasal resistance occurred primarily at the upstream or flow-limiting segment of the nasal airway.

Adult↗
PubMed1994

Maximal inspiratory pressure following endurance training at altitude.

Effects of endurance training on maximal inspiratory pressure and fatigue were evaluated after 5 weeks. Twelve male and 9 female untrained subjects were matched in the three groups for sex and maximal oxygen uptake (VO2 max). Training was performed at 70% VO2max; 45 min day-1; 5 days week-1 (n = 7); and at the same relative (n = 7) and absolute (n = 7) work loads in a pressure chamber corresponding to 2500 m (560 mmHg). Work load was increased every week to maintain the training heart rate. Maximal respiratory pressure was measured at the mouth before and 30, 60 and 120 s after maximal exercise. With no significant difference between the three groups of subjects, VO2max increased from 2.96 (1.98-4.47) (median and range for 21 subjects) to 3.33 (2.50-4.72) 1 min-1 (p < 0.001) and ventilation (VE max) from 109 (57-147) to 123 (73-148) 1 min-1 (p < 0.001), while maximal heart rate decreased from 193 (180-211) to 192 (169-207) beats min-1 (p < 0.01). Maximal inspiratory pressure (87 (56-115) mmHg), inspiratory muscle fatigue (18 (-2-43)%, p < 0.001), and arterial oxygen tension during exercise (12.4 (9.9-15.6)kPa) were similar before and after training. The results demonstrate that training at simulated altitude at 2500 m does not increase VE max or VO2 max above the increases obtained from training at sea level. Furthermore, VEmax and VO2 max increased approximately 13% despite unchanged maximal inspiratory pressure and inspiratory muscle fatigue.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2003

Relation of pulmonary responses induced by 6.6-h exposures to 0.08 ppm ozone and 2-h exposures to 0.30 ppm ozone via chamber and face-mask inhalation.

While direct comparison of pulmonary responses to 6.6-h exposures to 0.08 to 0.12 ppm ozone O3 have demonstrated that chamber and face-mask inhalation methods yield closely similar results, no comparative study of responses to 2-h intermittent exercise (IE) exposures to higher O3 concentrations have been reported. The present study was designed to achieve three primary objectives: (1) to compare pulmonary function and symptoms effects of a 2-h IE exposure to 0.30 ppm O3 via chamber and via face mask; (2) to compare the pulmonary effects of 6.6-h chamber exposure to 0.08 ppm O3 to those observed in 2-h IE 0.30 ppm O3 exposures via chamber and via face mask; and (3) to examine filtered air (FA) recovery pulmonary and symptoms responses following chamber exposures of 6.6 h to 0.08 ppm O3 and 2 h to 0.30 ppm O3. A simple regression of postexposure percent change in FEV(1.0) for the 2-h IE, 0.30-ppm O3 chamber exposure as a function of postexposure percent change in FEV(1.0) for the 2-h IE, 0.30-ppm O3 exposure with face mask yielded an R(2) of 0.83. Further, a regression of the postexposure FEV(1.0) response to the chamber 6.6-h, 0.08-ppm O3 exposure as a function of postexposure FEV(1.0) response to the face mask 2-h IE, 0.30-ppm O3 exposure (R(2) of 0.34) was similar to the 0.40 value obtained for the two chamber exposures FEV(1.0) response comparison. Results of the 1.4-h FA recovery following the two chamber O3 exposures showed different rates of FEV(1.0) and symptoms rectification that appeared related to the total O3 dose (product of O3 concentration, ventilation rate, and duration). More data are needed to clarify short-term recovery of O3-induced pulmonary effects and how they may be related to the more abundant data available on the delayed recovery of pulmonary function seen over longer time periods, such as 24 h.

Administration, Inhalation↗
PubMed2006

Antecedents of respiratory pauses in extremely low birth weight infants supported by proportional assist ventilation.

OBJECTIVE: To determine characteristics of breathing patterns prior to respiratory pauses in extremely low birth weight (ELBW) infants breathing spontaneously under proportional assist ventilation (PAV). METHODS: Thirteen infants (mean +/- SD: gestational age 25 +/- 1 weeks; birth weight 753 +/- 149 g; age 4 +/- 3 days) were studied. Recordings were obtained under PAV over two-hour periods on two consecutive days. The last 10 breaths preceding respiratory pauses were analyzed. RESULTS: Tidal volume, inspiratory and expiratory peak flow, and mean inspiratory flow decreased in the last breaths prior to respiratory pauses compared to all other breaths (p < 0.001). Of all apneas 89% were preceded by a decrease in tidal volume of at least 33% (435/487; p < 0.001). The positive predictive value of a decrease in tidal volume to predict an apnea was 26% (435/1640; p < 0.001). CONCLUSIONS: Decreases in tidal volume of at least 33% and in airflow are the predominant changes in the breathing pattern prior to respiratory pauses in ELBW infants, preceding 89% of all respiratory pauses. Their low positive predictive value of 26% however, indicates that further variables of breathing need to be implemented to predict cessation of breathing with higher precision.

Apnea↗
PubMed1999

Inspiratory flow rates through a novel dry powder inhaler (Clickhaler) in pediatric patients with asthma.

Inspiratory flow profiles through a novel dry powder inhaler (DPI) (Clickhaler; Innovata Biomed Ltd, St. Albans, UK) were recorded in 17 pediatric patients (aged 7-16 years) with stable mild to moderate asthma. Most patients (n = 14) could generate high peak inspiratory flows (PIFs) (> 60 L/min) and high flows early in the flow profile. These flows have been shown to be adequate to deaggregate and deliver micronized drug with this delivery system.

Administration, Inhalation↗