Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0700208 (scoliosis)
 8,574 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reduction in dead space through conventional tracheostomy has been used to treat patients with chronic CO2 retention. The insufflation of air directly into the trachea by transtracheal catheter (airway insufflation, AI) provides reductions in dead space as great or greater than those of tracheostomy. The physiologic effects of AI on gas exchange have not been adequately studied because instillation of gases into the trachea contaminates minute ventilation (VL), dead space volume (VD), tidal volume (VT), and other indices of gas exchange, as measured by usual technics. We overcame this problem by devising special methods of measuring inspired and expired ventilation, alveolar and dead space ventilation, and VT and VD by using pneumotachographic timing of inspiration and expiration so that true inspired and expired ventilation were calculated. We studied 5 patients with chronic CO2 retention from either COPD, scoliosis, or muscular dystrophy (annual average PaCO2 = 45 to 75 mm Hg) during 75 min of AI with serial gas exchange and arterial blood gas measurements. AI at about 5 L/min of room air through the trachea in 5 patients reduced VL by 18% (from 7.91 to 6.48 L/min), VT by 25% (from 450 to 338 ml), and VD by 37% (from 223 to 141 ml), while not affecting PaCO2 (from 51.8 to 48.2 mm Hg) or PaO2 (from 65.1 to 63.4 mm Hg). In 2 patients, AI administered continuously for 4 to 12 months (as 30 to 50% O2) maintained PaCO2 as well as or better than breathing enriched O2 from a tracheal collar via an open tracheostomy.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Airway insufflation: physiologic effects on acute and chronic gas exchange in humans. 250 22

The purpose of the lung is intrapulmonary gas exchange. The circulatory system delivers the respiratory gases to the tissue. The ventilatory pump however is responsible for the circulation of air between the lungs and the ambient atmosphere. Due to better diffusing capabilities, hypercapnia always is a result of pump failure and little dependent on the lung. Ventilatory failure, either compensated with an increased demand on the muscles or decompensated with an additional increase in pCO2, should be separated from lung failure where primarily oxygen exchange is involved. Decompensated hypercapnic ventilatory failure is then the indication for intermittent mechanical ventilation. The pCO2, either arterial or transcutaneously registered together with the noninvasive evaluation of the mouth occlusion pressures during tidal breathing and during a maximal inspiratory effort, define well the severity of ventilatory failure. In acute on chronic ventilatory failure, noninvasive mechanical ventilation in three randomised and controlled studies resulted in a better survival compared to intubation. To fulfil certain weaning criteria is no longer required in difficult to wean patients, as a transfer from invasive to noninvasive mechanical ventilation can be performed if only cooperativity is preserved together with a minimal capacity of spontaneous breathing. Weaning will thereafter occur by progressive relief from intermittent noninvasive ventilation. 2300 difficult to wean patients in Germany should profit from this approach. Chronic ventilatory failure as a result of neuromuscular disease or scoliosis of the thoracic spine are the classical indications. COPD and myasthenia gravis are under discussion as indications for intermittent mechanical ventilation with an increasing tendency to ventilate. Epidemiological data however can only be roughly estimated due to the heterogeneity of indication and selection of the patients.
 ...
PMID:[Epidemiology and diagnosis of intermittent self-ventilation]. 923 70

Intermittent non-invasive (or nocturnal mechanical ventilation) eliminates symptoms of hypoventilation and improves gas exchange in patients with chronic respiratory failure. Performing right heart catheterisation we studied the influence of nocturnal mechanical ventilation on pulmonary hemodynamics. We investigated 20 patients with restrictive thoracic diseases (Post-TBC: n = 9, scoliosis: n = 11, PaCO2: 59.8 +/- 7.6 mmHg) and 13 patients with COPD (n = 13, PaCO2: 58.5 +/- 7.8 mmHg). All patients were mechanically ventilated in controlled mode. During the study the medication was not changed; COPD patients with long-term oxygen maintained this therapy. Right-heart catheterisation was performed immediately before and after 1 year nocturnal mechanical ventilation. In patients with thoracic restriction NMV induced a marked reduction of pulmonary artery pressure (PAP) from 33.2 +/- 10.0 mmHg before to 24.8 +/- 6.2 mmHg after 1 year nocturnal mechanical ventilation. In the COPD group PAP increased from 25.3 +/- 6.0 mmHg before to 27.5 +/- 6.0 mmHg after 1 year nocturnal mechanical ventilation. In contrast to the COPD group in patients with chronic respiratory failure due to thoracic restriction nocturnal mechanical ventilation causes substantial reduction in pulmonary artery pressure after a one year application.
 ...
PMID:[Effect of intermittent ventilation on pulmonary hypertension in chronic respiratory failure]. 1061 59

Extreme mountain climbers and patients with stable but severe ventilatory insufficiency (e.g. obesitas hypoventilation-syndrome, scoliosis) sometimes experience a state of severe hypoxemia without any or only mild subjective disturbances. Organ failure is never observed in these periods. On the other hand there are two well documented studies concerning long term oxygen therapy (LTOT) that have shown in hypoxemic COPD-patients (pO 2 lower then 55 mm Hg) a doubling the life expectancy under oxygen. This contradiction can be elucidated if the influence of oxygen on the ventilation is taken into account. These study patients treated with LTOT all had more or less hypercapnia (hypoventilation) due to an overload of their respiratory pump. Oxygen reduces the ventilation (seen as hypercapnia) which leads to an unloading of the respiratory muscles. Later studies to LTOT found a positive correlation between the extent of stable hypercapnia and life expectancy. In this article the physiopathologic background of this findings are discussed. The main parameter of the regulator for the oxygen transport is not pO 2 but the oxygen content. The oxygen content multiplied by cardiac output determines the extent of oxygen delivery. Many regulatory systems (e.g. polyglobuly or expression of oxygen resistant isoenzymes of the respiratory chain) are involved to compensate the hypoxemia associated with hypoventilation which prevents an organ threatening hypoxia. This pathophysiologic finding has important impact on intensive care medicine, which usually takes only pO 2 into account for therapeutic decisions (e. g. high FiO 2 and high pressure support). This sometimes leads to "overtreatment", with possible harm to the patient.
 ...
PMID:[Overestimation of hypoxemia]. 1214 Jul 93