Showing papers on "Hypoventilation published in 1982"

Mass loading, sleep apnea, and the pathogenesis of obesity hypoventilation.

Abstract: To define the roles of mechanical loading, respiratory neuromuscular control, and sleep apnea in the pathogenesis of obesity hypoventilation, respiratory muscle drive and output, assessed by diaphragmatic electromyogram (EMGdi) and mouth occlusion pressure (P 0.15), respectively, were determined during CO2 chemostimulation in nonobese volunteers who were subjected to abdominal mass loading, and in three groups of markedly obese patients: eucapnic obese without sleep apnea (O), eucapnic obese with sleep apnea (OSA), and hypercapnic obese with sleep apnea (OH). The P0.15 responses were decreased in OSA and OH, but the EMGdi responses were not significantly different from those in control subjects. In O patients EMGdi responses were significantly greater than those in control subjects as well as those in OSA and OH patients. EMGdi and P0.15 responses increased in all nonobese subjects when they were subjected to mass loading. We conclude that both OSA and OH patients were equally unable to develop the expected increase in respiratory muscle drive and output. The presence of sleep apnea, possibly by causing nocturnal hypoxemia and/or sleep fragmentation, may result in impaired mass load compensation and predispose obese patients to develop hypercapnia.

Fluid Retention and Relative Hypoventilation in Acute Mountain Sickness

Abstract: The presence of pulmonary, cerebral, and/or peripheral edema in acute mountain sickness (AMS) implies a derangement in the body’s handling of water Previously, we demonstrated water retention and inc

Abnormalities of breathing control and airway maintenance in infants and children as a cause of cor pulmonale.

Abstract: Respiratory control abnormalities may result in cor pulmonale. This report summarizes the clinical history, diagnostic evaluation, treatment, and outcome of 16 infants and children presenting with cor pulmonale subsequently found to be due to sleep-dependent hypoventilation. Eleven patients had cardiomegaly and electrocardiographic evidence of right ventricular hypertrophy (RVH) while 5 had only severe RVH or biventricular hypertrophy (BVH). Four infants with central hypoventilation syndrome (CHS)—absence of sleep-related ventilatory drive—had severe sleep-dependent asphyxia and resultant acute respiratory failure; all were ultimately treated with phrenic nerve pacing. One patient with alveolar hypoventilation syndrome (AHS)—a partial deficit in ventilatory drive during sleep—presented with severe pulmonary hypertension and ultimately died despite symptomatic relief with respiratory stimulants. Eleven patients presented with obstructive sleep apnea (OSA) and sleep-dependent asphyxia secondary to intermittent complete or to prolonged partial upper airway obstruction. Localized airway obstruction due to an anomalous innominate artery in 1 child was corrected by arteriopexy. Four children underwent adenotonsillectomy (TA none presently has evidence of cor pulmonale. In summary, early recognition and appropriate treatment of respiratory control disorders will improve sleep ventilation, eliminate asphyxia during sleep, and prevent the development of cor pulmonale.

Hypoxemia During Hemodialysis

Abstract: patients with chronic renal failure receiving hemodialysis experience hypoxemia during routine dialysis. First reported, to our knowledge, by Johnson et al1in 1970, the fall in Pao2is typically 10% to 20% of baseline. This decrease is usually well tolerated,2but may be of critical importance in patients with limited pulmonary or cardiac reserve. We will review clinical evidence for pathophysiologic alterations—pulmonary and metabolic—that contribute to production of this hypoxemia. PHYSIOLOGIC APPROACH TO HYPOXEMIA Mechanisms of Arterial Hypoxemia Hypoxemia may result from five causes listed in the Table. Data needed to differentiate between these are shown. Categorization of hypoxemia physiologically aids in determining its cause, and provides a rational basis for choosing therapy. Alveolar Gas Equation and Arterial-Alveolar Po2 Difference In the Table, calculation of the arterial-alveolar PO2difference (aADO2) provides the basis for distinguishing reduced fraction of oxygen in inspired air (FiO2) and hypoventilation

Incidence of Apnea in Siblings of Sudden Infant Death Syndrome Victims Studied at Home

Abstract: Victims of sudden infant death syndrome (SIDS) have been shown to have pathologic abnormalities consistent with chronic hypoxia.1-7 Two groups of infants at high risk of dying of SIDS, near miss infants and subsequent siblings of SIDS victims, have been studied in attempts to demonstrate physiologic abnormalities that could account for these pathologic findings. Investigators have found abnormalities in breathing pattern and the respiratory control system in the former consisting of prolonged sleep apnea, excessive short apnea, periodic breathing, hypoventilation, and depressed response to hypercarbia.8-13 However, studies in the SIDS sibling group have demonstrated varying results of excessive periodic breathing in the home14 and decreased apnea in the laboratory.15

Paraneoplastic brainstem encephalitis with acute dystonia and central hypoventilation

Abstract: A 55-year-old patient with known lung cancer was admitted with dystonia of the right arm, lockjaw, horizontal gaze palsy and dysphagia. Prior to death total ophthalmoplegia and central hypoventilation developed. Postmortem examination showed brainstem encephalitis, gangioradiculoneuritis, posterior column degeneration and loss of cerebellar Purkinje cells. These changes are considered to constitute a combined paraneoplastic syndrome. The dystonic movement disorder and central hypoventilation and their possible morphologic correlates are discussed.

Sleep-induced nonobstructive hypoventilation associated with diaphragmatic paralysis.

Abstract: A patient with adult-onset spinal muscular atrophy causing mild proximal limb muscle weakness had sleep-induced nonobstructive hypoventilation due to diaphragmatic paralysis. Nocturnal dyspnea and daytime somnolence were associated with frequent arousals from sleep due to arterial oxygen desaturation. The nocturnal use of a cuirass respirator improved the oxygen saturation, resulting in less disrupted sleep, relief of the somnolence, and improved daytime ventilation.

Limitations of jet ventilation through the laryngoscope

Abstract: A series is presented of 100 patients who underwent direct laryngoscopy under general anaesthesia. Our preferred technique of ventilation is jet insufflation by an injector attached to the blade of the laryngoscope, as it provides the surgeon with a quiet and completely exposed larynx. In nine cases, chest expansion was assessed as inadequate by the anaesthetist. These patients were obese with a short neck, and/or stiff-necked; thus, insertion of the laryngoscope was difficult and a good seal between it and the larynx could not be achieved. Arterial blood gas values in six of these patients demonstrated marked hypoventilation. To improve ventilation in these patients an alternative technique of insufflation through a nasotracheal catheter was used. Arterial blood gas values indicated that this method resolved the problem of hypoventilation. Although the catheter somewhat limits the view of the endolarynx, the improved ventilation outweighs the drawbacks of this technique. It is suggested that for the obese and/or stiff-necked patient, a nasotracheal catheter be used electively for ventilation.

Infantile hypoventilation syndrome, neurenteric cyst, and syringobulbia

Abstract: Hypoventilation syndrome was observed in an infant with a neurenteric cyst. She died at 9 months of age following episodic bradycardia and the loss of voluntary as well as autonomic respiratory control. There was a mediastinal neurenteric cyst with anterior spina bifida and extension into the upper thoracic spinal cord. Secondary syringomyelobulbia was present at necropsy. The syringobulbia involved the hypoglossal nuclei, the dorsal motor nuclei of the vagus in the lower medulla, the right nucleus ambiguus, the right fasciculus and nucleus solitarius, the right mediolateral reticular formation, and the right dorsal motor nucleus of the vagus at the level of the obex. This morphologic distribution is attributed to the intraspinal rupture and upward extension of the mucinous contents of the cyst, and appears to be responsible for the hypoventilation syndrome.

The effects of localized hypoventilation on ventilation/perfusion (V/Q) ratios and gas exchange in the dog lung.

Abstract: 1. Hypoventilation of one lobe of lung was studied in open-chest anaesthetized dogs. Lobar blood flow, pulmonary-artery pressure and gas exchange were measured, the latter from breath-by-breath analysis with a mass spectrometer. 2. Hypoventilation of the lobe by reducing the respiratory pump stroke led, at each step, to a reduction in blood flow to that lobe. The flow (Q) reduction was variable, but always less than the ventilation (VE) reduction, so that the V/Q ratio to the lobe was reduced. O2 tension and pH fell and CO2 tension rose in effluent blood. Thus V/Q regulation achieved by flow reduction varied between individuals and was of low gain. 3. Anatomical or series dead space (VD series) was reduced in proportion to ventilation. When VD series was less than the apparatus dead space, some gas exchange still took place. 4. Oxygen uptake (VO2) and CO2 output (VCO2) were reduced during hypoventilation. VCO2 fell more than VO2, so that the respiratory exchange ratio (R) was reduced. 5. Whether the deterioration in gas tensions in effluent blood during hypoventilation of the lobe was due to shunt of blood past unventilated alveoli, or to V/Q mismatching, was not resolved. 6. The plateau phase of the CO2-output curves at low tidal volumes was usually regular; thus either hypoventilation was uniform, or some ventilation units were totally closed.

[Most frequent causes, complications and differential diagnosis of neonatal respiratory distress in chest x-ray].

Abstract: The radiologic changes of the chest X-ray of 270 newborns with respiratory distress were analyzed. In cases of Hyaline Membranes the chest X-ray showed finely granular evenly disseminated structures combined with signs of hypoventilation. Localized, patchy, streaky, homogenous and reticulonodular shadows were found in cases of pneumonia and hemorrhage. Hyperinflation were an additional sign for an inflammatory disease. This symptom was also demonstrated in pulmonary bleeding, but was less common. The bilateral interstitial augmentation of the pulmonary structure in combination with cardiomegaly was mainly a symptom for cardial insufficiency and transient tachypnea. The differentiation between fine granular and reticulo-nodular structures should create no problem if the chest X-ray if of good quality. Extrapulmonary air collections were found in a high percentage in the course of artificial ventilation as a consequence of the "baro-trauma." The radiologic diagnosis of BPD was no problem. The value of the chest X-ray lies in the demonstration of a pulmonary cause for the respiratory distress, in the demonstration of complications and in the radiological observation of the disease.

Hypercarbia in the infant with congenital cardiac disease

Abstract: Three infants are described who illustrate 3 distinct mechanisms by which cardiac disease may cause carbon dioxide retention: 1) hypoventilation 2) large alveolar dead space and 3) decreased effective pulmonary blood flow.

[Alterations of blood gases during sleep and consciousness in surgical patients (author's transl)].

Abstract: Measurements of blood gases and respiratory rate were made in 63 surgical patients during consciousness and sleep. Sleep-induced hypoventilation results in significant alteration of arterial PO2 and PCO2. The therapeutic possibilities to avoid critical postoperative hypoxaemia are intermittent positive pressure ventilation, mobilisation of the patient and O2 insufflation.