Vital Capacity

Theophylline is effective in the treatment of central apneas and periodic breathing. In obstructive sleep apnea syndrome (OSAS), results of pharmacological monotherapy with theophylline are inconsistent. The present study investigates whether additional theophylline in patients with OSAS and continuous positive airway pressure (CPAP) therapy might improve ventilation, lower effective CPAP pressure levels or affect sleep architecture.

In this retrospective study, we identified patients with repaired tetralogy of Fallot were in the database of the Abstract Background: We investigated the aerobic capacity of 168 adult patients who had undergone successful surgical repair of tetralogy of Fallot at the University of Toronto Congenital Cardiac Centre for Adults. Methods: We compared values of peak uptake of oxygen, peak heart rate, forced vital capacity, and forced expiratory volume in 1 second to predicted values for their age groups. Results: The patients who had undergone surgical repair of tetralogy of Fallot demonstrated an overall diminished peak uptake of oxygen, at 51%, and peak heart rate, at 79%, compared to predicted values. No difference in peak aerobic capacity was found according to the initial surgical strategy of palliation or repair. Conclusions: Adult patients who have undergone surgical repair of tetralogy of Fallot have lower peak uptake of oxygen, and peak heart rate, compared to predicted values. The reduction in the peak heart rate may affect their exercise capacity. The peak uptake of oxygen also decreased with increasing age at the time of testing, and the age at surgical repair.

The effectiveness of three deep breathing techniques was evaluated in 98 male patients after coronary artery bypass graft surgery in a randomized trial. The techniques examined were deep breathing with a blow bottle-device, an inspiratory resistance-positive expiratory pressure mask (IR-PEP) and performed with no mechanical device. Pulmonary function and roentgenological changes were evaluated. Four days post-operatively there were signicantly decreased vital capacity, inspiratory capacity, forced expiratory volume in 1 second, functional residual capacity, total lung capacity and single-breath carbon monoxide diffusing capacity in all three groups (p < 0.0001). No major differences between the treatment groups were found, but the impairment in pulmonary function tended to be less marked using the blow bottle technique. The Blow bottle group had signi cantly less reduction in total lung capacity (p = 0.01) compared to the Deep breathing group, while the IR-PEP group did not signi cantly differ from the other two groups.

The carbon dioxide test-a vital capacity breath of air containing 35% carbon dioxide (CO 2 )-provokes panic attacks in many individuals with panic disorder (PD). It has thus been extensively used as an experimental model of panic and less frequently as a clinical method of provoking symptoms for interoceptive exposure treatment. Recently, stress researchers have suggested another use for the CO 2 test: that of an acute physiological stressor indexing the human stress response. The purpose of this review is to synthesize findings about the effects of the CO 2 test from both the panic and stress literatures in order to advance understanding about this increasingly popular test. Both panic and stress researchers have examined the fleeting effects of the CO 2 test, finding that the test engenders transient breathlessness, dizziness, and minor anxiety in most participants and panic attacks in those with or at risk for PD. Physiological measurements after the test indicate a brief homeostatic disruption in many bodily systems, including increased respiration, systolic blood pressure, and noradrenaline, and decreased heart rate. Most studies indicate increased cortisol. Possible benefits of integrating findings from the panic and stress research lines, given their common use of the CO 2 test, are discussed.

Respiratory failure associated with Guillain Barré syndrome. Severe involvement of the respiratory muscles is seen in 25% of patients with a diagnosis of Guillain Barré syndrome. In order to evaluate the clinical characteristics and evolution of this disorder we reviewed the clinical records of patients admitted with this diagnosis to our Hospital between January 1987 and December 1996. We identified 44 patients with respiratory failure. The age was 34.0 ± 14.1 years, 31 patients were male and 13 female; 70.5% required mechanical ventilation (MV). The time elapsed between the beginning of symptoms and MV was 9.4 ± 8.0 days. Total duration of MV was 1.224 ± 1.208 hours. Patients who required ventilatory support during the first 48 hours of evolution had a significantly longer duration of MV compared to the rest of the group (2.100 ± 2.076 vs 934 ± 735 hours, p &lt; 0.05). Two of the survivors needed ventilatory support for more than 6 months. All patients showed quadriparesia, 55% ha...

Although ventilatory failure is the most common cause of death in amyotrophic lateral sclerosis (ALS) and measurement of respiratory muscle strength (RMS) has been shown to have prognostic value, no single test of strength can predict the presence of hypercapnia reliably. RMS was measured in 81 ALS patients to evaluate the relationship between tests of RMS and the presence of ventilatory failure, defined as a carbon dioxide tension &amp;amp;amp;amp;amp;amp;amp;gt; or = 6 kPa. We studied the predictive value of vital capacity (VC), static inspiratory and expiratory mouth pressures (MIP, MEP), maximal sniff oesophageal (sniff P(oes)), transdiaphragmatic (sniff P(di)) and nasal (SNP) pressure, cough gastric (cough P(gas)) pressure and transdiaphragmatic pressure after bilateral cervical magnetic phrenic nerve stimulation (CMS P(di)) to identify the risk of ventilatory failure in the whole group and in subgroups of patients with and without significant bulbar involvement. For patients without significant bulbar involvement, sniff P(di) had greatest predictive power [odds ratio (OR) 57] with specificity, sensitivity and positive and negative predictive values (PPV, NPV) of 87, 90, 74 and 95%, respectively Of the less invasive tests, per cent predicted SNP had greater overall predictive power (OR 25, specificity 85%, sensitivity 81%) than per cent predicted VC (9, 89%, 53%) and per cent predicted MIP (6, 83%, 55%). No test had significant predictive power for the presence of hypercapnia when used to measure RMS in a subgroup of patients with significant bulbar weakness. Thirty-five patients underwent polysomnography. CMS P(di), sniff P(di) and per cent predicted SNP were significantly correlated with the apnoea/hypopnoea index (AHI) (P = 0.035, 0.042 and 0.026, respectively). The correlations between AHI and per cent predicted MIP and VC were less strong (both non-significant). In ALS patients without significant bulbar involvement, novel tests of RMS have greater predictive power than conventional tests to predict hypercapnia. In particular, the non-invasive SNP is more sensitive than VC and MIP, suggesting that it could usefully be included in tests of respiratory muscle strength in ALS and will be helpful in assessing the risk of ventilatory failure. In patients with significant bulbar involvement, tests of respiratory muscle strength do not predict hypercapnia. Sleep-disordered breathing is correlated with RMS and the novel tests of RMS having the strongest relationship with the degree of sleep disturbance.

Patients affected by glycogenosis type II frequently present sleep disordered breathing. The presence of symptoms suggestive of sleep breathing disorders was investigated, by a questionnaire, in 10 patients, affected by adult or juvenile forms of glycogenosis type II. Diurnal respiratory function, diaphragm weakness and nocturnal respiratory pattern were evaluated at the enrolment. In patients presenting sleep disordered breathing, the same parameters were re-evaluated after treatment with assisted non invasive ventilation. Out of 10 patients, 5 presented symptoms suggestive of sleep-disordered breathing at the baseline, 2 a pattern of sleep apnea syndrome and 3 nocturnal hypoventilation. All patients presented diaphragmatic weakness. No correlation was found between forced vital capacity values (FVC) in sit position and nocturnal respiratory disorders. Five patients with respiratory disorders were treated with non invasive ventilation. All patients - after one month of treatment - ...