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PubMed1998

Resistive inspiratory muscle training in subjects with chronic cervical spinal cord injury.

OBJECTIVE: To determine whether pulmonary function, respiratory muscle strength, and dyspnea can be improved in individuals with chronic cervical spinal cord injury (SCI). STUDY DESIGN: Ten subjects participated in an 8-week resistive inspiratory muscle training (IMT) program for 15 minutes twice daily. Spirometry, lung volumes, maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), and dyspnea were measured at baseline, week 4, and week 8. Six months after the study, spirometry, MIP, and MEP were re-measured in a subgroup of the original participants. RESULTS: We found that regular IMT in subjects with cervical SCI significantly improved forced vital capacity (means +/- SE) (11% +/- 2.82% increase), forced inspiratory vital capacity (21% +/- 6.91%), vital capacity (8% +/- 4.36%), total lung capacity (12% +/- 3.23%), functional residual capacity (15% +/- 5.96%), and MIP (24% +/- 6.98%) (p < .05). Furthermore, although no statistical differences were observed for the dyspnea scale, the fact that subjects reported decreased levels (43% +/- 21.30% reduction) of perceived difficulty breathing may be of greater importance. No significant differences from baseline values were found in the seven subjects whose spirometry and respiratory muscle strength were measured 6 months after the study. CONCLUSIONS: Our findings suggest that in individuals with cervical SCI regular resistive IMT may result in decreased restrictive ventilatory impairment and reported dyspnea and, thus, reduced incidence of chronic respiratory complaints, respiratory infection, and other pulmonary complications.

Adult↗
PubMed1989

Effects of abdominal opening on respiratory system mechanics in ventilated rats.

In 16 anesthetized paralyzed mechanically ventilated rats, respiratory system mechanics and rib cage dimensions were determined both before and after wide abdominal opening. In eight animals the end-inflation occlusion method disclosed statistically significant postoperative increases in respiratory system elastance (from 4.84 to 6.49 cmH2O.ml-1) and resistance (from 0.224 to 0.300 cmH2O.ml-1.s); the latter resulted from a rise of its uneven component (from 0.161 to 0.209 cmH2O.ml-1.s). In the remaining rats, rib cage morphometry at functional residual capacity after surgery showed significant decreases in lower rib cage circumference and anteroposterior and lateral diameters, whereas there was an increase in upper rib cage circumference and a fall in its lateral diameter. When these parameters were measured at end-inspiratory lung volume, the difference between intact and open abdomen were less striking; only lower rib cage circumference and upper rib cage lateral diameter significantly decreased postoperatively. Because surgery induced an expiratory volume of only 0.1 ml, it can be concluded that abdominal opening redistributed regional volumes within the lung, leading to increased unevenness in the system.

Abdomen↗
PubMed1999

Training of the respiratory muscles in individuals with tetraplegia.

STUDY DESIGN: An experimental cross-sectional design. OBJECTIVES: To evaluate whether training of the innervated respiratory muscles in individuals with a (partial) cervical spinal cord injury will improve the strength and endurance capacity of these muscles and the exercise performance in these individuals. SETTING: Department of Physiology and Pulmonary diseases, Nijmegen, The Netherlands. METHOD: In this study nine individuals with tetraplegia (C3 C7) performed a target flow endurance training of the inspiratory muscles, twice a day for 15 min. First, the subjects performed a 'sham' training for 6 weeks with no appreciable resistance, after that they performed a 'real' training for 6 weeks with a resistance of 70% of the maximal endurance capacity of the inspiratory muscles. The training was evaluated at 0, 6 and 12 weeks by the following tests: (1) the slow Inspiratory Vital Capacity (IVC) and the Forced Inspiratory and Expiratory Volumes over 1 s (FIV1 and FEV1); (2) the Maximal Inspiratory Mouth Pressure (Pimax) and the Endurance Pressure (Pendu) and (3) a maximal arm-cranking exercise test. RESULTS: After the sham training, the Pendu was increased from 3.98 to 4.71 kPa with a P-value of 0.05. The sham training had no influence on any of the other variables. The real training had no effect on the IVC, FIV1, FEV1 and Pimax, however, increased the Pendu from 4.71 to 6.16 kPa (P=0.01), representing the respiratory muscle-endurance capacity. The oxygen consumption (VO2 peak) in the maximal exercise test improved from 0.87 to 0.98 l/min (P = 0.05). CONCLUSION: The results of the study indicate that training of the respiratory muscles results in an enhanced endurance capacity of these muscles and a concomitant increase in the aerobic exercise performance.

Adult↗
PubMed2001

Ministernotomy versus complete sternotomy for coronary bypass operations: no difference in postoperative pulmonary function.

OBJECTIVES: Less-invasive approaches in cardiac operations offer certain cosmetic advantages, but it is unclear whether there are additional positive effects with regard to the postoperative recovery of patients. The aim of this prospective and randomized study was to ascertain whether partial inferior midline sternotomy can improve pulmonary function, one of the best quantifiable parameters of postoperative recovery, after coronary artery bypass operations when compared with the standard full midline approach. METHODS: One hundred patients scheduled for elective coronary artery bypass grafting were randomized either for a full median sternotomy (standard sternotomy group, n = 50) or for a partial inferior sternotomy (ministernotomy group, n = 50). The following pulmonary features were assessed: vital capacity, forced expiratory volume, percentage of forced expiratory volume from vital capacity, total lung capacity, residual volume, maximum inspiratory pressure, and maximum expiratory pressure. Tests were performed preoperatively and on the fourth and tenth postoperative days. RESULTS: On the fourth postoperative day, both groups had a significant decrease in vital capacity (percentage of predicted values) when compared with preoperative values (preoperative vs fourth day: standard sternotomy group, 87.8% +/- 14.3% vs 42.1% +/- 10.2% [P <.0001]; ministernotomy group, 84.5% +/- 14.3% vs 41.5% +/- 11.8% [P <.0001]), with a significant tendency for recovery from the fourth to the tenth postoperative day (fourth vs tenth postoperative day: standard sternotomy group, 42.1% +/- 10.2% vs 66.3% +/- 12.3% [P =.001]; ministernotomy group, 41.5% +/- 11.8% vs 61.3% +/- 13.1 % [P =.002]). There were no differences in any test results between the groups on either the fourth or the tenth postoperative day. CONCLUSION: A less-invasive approach for coronary artery bypass operations with a partial inferior sternotomy does not improve early postoperative pulmonary function when compared with the conventional approach with a full sternotomy.

Coronary Artery Bypass↗
PubMed1980

Subclinical reduction in airflows after Teflon injection of vocal cord.

Results of intracordal Teflon injection for symptoms of unilateral vocal cord paralysis have been excellent. There seems to be no significant long-term foreign body reaction or limitation to maximum airflows. However, acute inflammatory reactions and airflow obstruction have been reported. The objective of the present study was to evaluate the frequency, extent, and duration of airway obstruction following Teflon injection. Forced inspiratory and expiratory airflows were measured in seven consecutive patients before, 24 hours, and 10 days after Teflon injection. Significant variable upper airway obstruction, as demonstrated by an increase in the ratio of forced expiratory airflows at 50% Vital Capacity to the forced inspiratory airflows at the same lung volume (VE50/VI50), was found in each subject. At 24 hours after the injection this ratio increased from a baseline of .098 +/- 0.50 (mean +/- S.D.) to 1.41 +/- 0.67 (P less than 0.01), and returned to baseline values in 10 days (0.95 +/- 0.14). We conclude that Teflon injection into a paralyzed vocal cord creates a significant inspiratory airway obstruction that is reversible in 10 days.

Adult↗
PubMed1985

Safe use of PEEP in patients with severe head injury.

Thirty-three patients with severe head trauma were studied to determine whether the use of positive end-expiratory pressure (PEEP) would cause an increase in intracranial pressure (ICP). Changes in ICP induced by PEEP were then correlated with a panel of physiological variables to try to explain these changes. Mean ICP increased from 13.2 +/- 7.7 mm Hg (+/- standard deviation) to 14.5 +/- 7.5 mm Hg (p less than 0.005) due to 10 cm H2O PEEP, but the eight patients with elevated baseline ICP experienced no significant increase. Cardiac output and venous admixture (Qs/Qt) declined significantly, while central venous pressure, peak inspiratory pressure, functional residual capacity, and arterial pCO2 increased significantly due to PEEP. Blood pressure and cerebral perfusion pressure were unchanged. The change in ICP due to PEEP correlated significantly with a combination of cardiac output, peak inspiratory pressure, Qs/Qt, and changes in blood pressure and arterial pCO2 due to PEEP, indicating that the effect of PEEP on ICP could be largely explained by its effect on hemodynamic and respiratory variables. No patient deteriorated clinically due to PEEP. It is concluded that 10 cm H2O PEEP increases ICP slightly via its effect on other physiological variables, but that this small increase in ICP is clinically inconsequential.

Brain Injuries↗
PubMed1985

Inspiratory resistance versus general physical training in patients with chronic obstructive pulmonary disease.

The effect of inspiratory muscle training (IMT) three times daily for 6 weeks was compared with that of general physical training (PT) (stair climbing) in 10 out-patients with severe chronic obstructive pulmonary disease (COPD). PT improved 12 min walking distance (12MWD) by 19% (1-28), stair climbing ability (SCA) over four floors at maximum speed by 11% (3-50), maximum oxygen uptake by 10% (2-33), inspiratory flow by 85% (19-113) and improved an index of breathlessness by 44% (3-786). During IMT, 12MWD and SCA decreased by 8% (0-33) and 10% (0-161), respectively, and the other variables decreased by 6-10%. No changes were seen in ventilation during maximum exercise, in maximum inspiratory and expiratory pressures, or in variables measured during spirometry. Thus work capacity can be improved by training in COPD maybe because of an increase in inspiratory flow rate, but without a change in maximum exercise ventilation.

Aged↗
PubMed2001

Perception of bronchoconstriction in smokers with airflow limitation.

To our knowledge, no data have been provided as to whether and to what extent dynamic hyperinflation, through its deleterious effect on inspiratory muscle function, affects the perception of dyspnoea during induced bronchoconstriction in patients with chronic airflow obstruction. We hypothesized that dynamic hyperinflation accounts in part for the variability in dyspnoea during acute bronchoconstriction. We therefore studied 39 consecutive clinically stable patients whose pulmonary function data were as follows (% of predicted value): vital capacity (VC), 97.8% (S.D. 16.0%); functional residual capacity, 105.0% (18.8%); actual forced expiratory volume in 1 s (FEV(1))/VC ratio, 56.1% (6.3%). Perception of dyspnoea using the Borg scale was assessed during a methacholine-induced fall in FEV(1). The clinical score and the treatment score, the level of bronchial hyper-responsiveness and the cytological sputum differential count were also assessed. In each patient, the percentage fall in FEV(1) and the concurrent Borg rating were linearly related, with the mean slope (PD slope) being 0.09 (0.06). The percentage fall in FEV(1) accounted for between 41% and 94% of the variation in the Borg score. At a 20% fall in FEV(1), the decrease in inspiratory capacity (Delta IC) was 0.156 (0.050) litres. Patients were divided into three subgroups according to the PD slope (arbitrary units/% fall in FEV(1)): subgroup I [eight hypoperceivers; PD slope 0.026 (0.005)], subgroup II [26 moderate perceivers; 0.090 (0.037)] and subgroup III [five hyperperceivers; 0.200 (0.044)]. By applying stepwise multiple regression analysis with the PD slope as the dependent variable, and other characteristics (demographic, clinical and functional characteristics, smoking history, level of bronchial hyper-responsiveness and sputum cytological profile) as independent variables, Delta IC (r(2)=45%, P<0.00001) and to a lesser extent treatment score (r(2)=17.3%, P<0.0006), and to an even lesser extent age (r(2)=3%, P<0.05), independently predicted a substantial amount (r(2)=65.27%, P<0.00001) of the variability in the Borg slope. Thus acute hyperinflation, and to a lesser extent treatment score and age, account in part for the variability in the perception of dyspnoea after accounting for changes in FEV(1) during bronchoconstriction in patients with chronic airflow obstruction.

Analysis of Variance↗
PubMed1979

Measurement of ventilatory reserve as an indicator for early extubation after cardiac operation.

The decision to perform tracheal extubation in 44 patients who underwent cardiac operation was based on an assessment of mental alertness, recovery of muscle strength, hemodynamic stability, and adequacy of pulmonary gas exchange. No patients required reintubation. Concomitant measurements of vital capacity (VC) and maximal inspiratory pressure (PImax) were made before a trial of spontaneous ventilation was commenced, after 45 minutes of spontaneous ventilation, and after tracheal extubation. By generally accepted criteria, these measurements suggested the need for continuing mechanical ventilation in 14 patients at the time mechanical ventilatory support was removed and in eight patients at the time of tracheal extubation. In this study, consideration of measurements of VC and PImax would have led to longer trachael intubation, especially in those patients who were extubated within 10 hours of the completion of anesthesia.

Anesthesia, General↗
PubMed2003

Effect of inspiratory muscle training in patients with multiple sclerosis.

OBJECTIVE: To evaluate whether inspiratory muscle training (IMT) improves inspiratory muscle strength, respiratory capacity, fatigue, and subjective perception of physical endurance in patients with advanced multiple sclerosis (MS). DESIGN: Randomized controlled trial. SETTING: Outpatient clinic in Sweden. PARTICIPANTS: Fifteen severely disabled patients with MS, randomized to a training or control group. INTERVENTION: Seven patients trained with a Threshold inspiratory muscle trainer, twice every other day, with 3 sets of 10 loaded inspirations (40%-60% of patients' maximal inspiratory pressure [Pimax]) over a 10-week period. MAIN OUTCOME MEASURES: Spirometry, Pimax, maximal expiratory pressure (Pemax), clinical assessments, and questionnaires on the patients' fatigue severity and physical endurance were evaluated. RESULTS: After training, the Pimax (P<.008) and Pemax (P<.02) increased in the training group. The improvement in Pimax after 10 weeks of training was higher than the improvement in the control group (P<.01) and was maintained 1 month after the training period ended. The training affected neither respiratory function nor the patients' symptoms. CONCLUSIONS: IMT had a beneficial effect on inspiratory muscle strength in patients with MS and is recommended as a complement to ordinary physical training.

Adult↗
PubMed1989

Respiratory muscle training in multiple sclerosis: a pilot study.

We assessed the effects of respiratory muscle training (RMT) in patients with multiple sclerosis (MS) on vital capacity (VC), maximal static inspiratory (PImax) and expiratory (PEmax) pressures and maximal voluntary ventilation (MVV). Eight patients (mean age 53, range 42 to 65 years) with stable disease and respiratory muscle weakness (RMW; VC = 83%, PImax = 64%, PEmax = 41%, MVV = 62% of predicted value) underwent a 4 +/- 1 week RMT program using inspiratory and/or expiratory resistive loads. Results showed changes in PImax (+31%, p less than 0.02), PEmax (+31%, p less than 0.05), and MVV (+21%, p less than 0.05); VC was unchanged (+1%). Thus in these patients, RMT improved respiratory muscle strength and ventilatory capacity. RMT may be an additional method of rehabilitation in selected patients with MS, in whom RMW contributes to exercise intolerance, coughing and talking impairment.

Adult↗
PubMed1992

Evaluation of phrenic nerve and pulmonary function in hereditary motor and sensory neuropathy, type I.

Phrenic nerve and diaphragmatic dysfunction has been assumed to be the cause of respiratory failure in hereditary motor and sensory neuropathy, type 1 (HMSN I). In order to determine the relationship between phrenic nerve and pulmonary function in this disease, 25 patients underwent a 4-step evaluation process consisting of: (1) bilateral phrenic nerve conduction study; (2) median, peroneal, and tibial motor conduction studies; (3) measurement of forced vital capacity (FVC) and maximal inspiratory and expiratory pressures (MIP, MEP); and (4) pulmonary-focused history and physical. Phrenic nerve motor latency was abnormally prolonged in 22 of the 23 (96%) subjects when a response was obtained. All had slowed velocity or absent peripheral motor conduction responses. Vital capacity was abnormally reduced in 6 of the 25 (24%) subjects. Eight (32%) had an abnormally reduced MIP, while 19 (76%) had an abnormally reduced MEP. Only 2 (8%) subjects had clinical evidence of pulmonary dysfunction. None of the dependent variables (FVC, MIP, MEP, peripheral nerve conduction, or clinical examination) correlated with phrenic nerve latencies. Although phrenic nerve latencies are markedly prolonged in HMSN I, these values are not useful in predicting respiratory dysfunction.

Adult↗
PubMed1978

Airflow in unilateral vocal cord paralysis before and after Teflon injection.

The effect of unilateral vocal cord paralysis and intracordal Teflon injection on maximum expiratory and inspiratory flows was studied in 15 consecutive patients. Ten patients had a ratio of forced expiratory flow to forced inspiratory flow at 50% vital capacity (Ve50/Vi50) more than one. Of the remaining five, four had low Ve50 consistent with underlying bronchial disease. Repeat studies were obtained in 10 patients two or more weeks after Teflon injection into a vocal cord for voice therapy. Maximum expiratory flow rates did not change (means 6.64 +/- 0.881/sec before and 6.47 +/- 1.101/s after injection). Inspiratory flow at 50% vital capacity improved in all six patients with a forced expiratory volume in one second (FEV1) greater than 75% of the forced vital capacity (FVC). In patients with an FEV1 less than 75% FVC, no consistent changes could be seen. We conclude that a high Ve50/Vi50 suggestive of variable extrathoracic airways obstruction is a frequent finding in the presence of unilateral vocal cord paralysis. Teflon injection does not cause a significant reduction in forced expiratory flows and improves inspiratory flows in subjects without evidence of underlying bronchial disease.

Airway Obstruction↗
PubMed1981

Laryngomalacia and inspiratory obstruction in later childhood.

Pulmonary function and symptoms were reviewed in 20 children in whom laryngomalacia had been diagnosed by direct laryngoscopy in infancy. Most children developed stridor in the first 2 weeks, but 3 children did not develop it until age 3 months. The mean duration of stridor was 4 years 2 months, with a range of 4 months to 12 years 7 months. Six children had marked posseting as infants. Airway dynamics were assessed by flow volume loops. All except one had normal expiratory flow volume curves. Inspiratory abnormalities were detected in 7 children; 6 were assessed as having variable extrathoracic inspiratory obstructions and 1 had a fixed obstruction consistent with subglottic stenosis. The mean ratios of maximal inspiratory flow at 50% of vital capacity divided by forced vital capacity in the laryngomalacia and control groups differed significantly, as did the mean ratios of maximal expiratory flow to maximal inspiratory flow at 50% of forced vital capacity. Laryngomalacia is not necessarily a benign disorder of limited duration; there may be persisting inspiratory obstruction in later childhood.

Age Factors↗
PubMed2000

The frequency and correlates of dyspnea in patients with advanced cancer.

Dyspnea is a devastating symptom in patients with advanced cancer. Unfortunately, very limited research has been done on the frequency and correlates of dyspnea in this particular patient population. The purpose of this prospective study was to assess the frequency of moderate to severe dyspnea and the correlates of dyspnea in a population of ambulatory terminally ill cancer patients. One hundred thirty-five consecutive patients attending a multidisciplinary pain clinic were tested for respiratory function (vital capacity, peak flow, maximal inspiratory pressure, and oxygen saturation). All patients gave their rating of dyspnea, anxiety, and fatigue/tiredness using visual analogue scales (VAS). Lung involvement by the tumor (primary or metastatic) was determined from the patient's chart. Moderate dyspnea occurred in 74/135 (55%) patients with terminal cancer. Lung involvement (r = 0.285, P = 0. 0009), anxiety (r = 0.306, P = 0.0003), fatigue/tiredness (r = 0.211, P = 0.0146), and vital capacity (r = -0.189, P = 0.0444) were significantly correlated with the intensity of dyspnea. Multivariate analysis demonstrated that lung involvement (P = 0.0016) and anxiety (P = 0.0027) were independently correlated with the intensity of dyspnea. In the subgroup of patients with moderate to severe dyspnea, multivariate analysis found anxiety (P = 0.0318) and maximal inspiratory pressure (P = 0.0187) to be independent correlates of the intensity of dyspnea. Dyspnea is a frequent symptom in patients with advanced cancer. The presence of cancer in the lungs, anxiety, and maximal inspiratory pressure are correlates of the intensity of dyspnea in this patient population. Possible treatments addressing low maximal inspiratory pressure and anxiety are needed, as well as further research in finding new correlates of dyspnea in advanced cancer patients.

Aged↗