Hypoventilation

About: Hypoventilation is a research topic. Over the lifetime, 1772 publications have been published within this topic receiving 40799 citations. The topic is also known as: respiratory depression.

Positive outcome of average volume-assured pressure support mode of a Respironics V60 Ventilator in acute exacerbation of chronic obstructive pulmonary disease: a case report.

Abstract: We were able to treat a patient with acute exacerbation of chronic obstructive pulmonary disease who also suffered from sleep-disordered breathing by using the average volume-assured pressure support mode of a Respironics V60 Ventilator (Philips Respironics: United States). This allows a target tidal volume to be set based on automatic changes in inspiratory positive airway pressure. This removed the need to change the noninvasive positive pressure ventilation settings during the day and during sleep. The Respironics V60 Ventilator, in the average volume-assured pressure support mode, was attached to our patient and improved and stabilized his sleep-related hypoventilation by automatically adjusting force to within an acceptable range. Our patient was a 74-year-old Japanese man who was hospitalized for treatment due to worsening of dyspnea and hypoxemia. He was diagnosed with acute exacerbation of chronic obstructive pulmonary disease and full-time biphasic positive airway pressure support ventilation was initiated. Our patient was temporarily provided with portable noninvasive positive pressure ventilation at night-time following an improvement in his condition, but his chronic obstructive pulmonary disease again worsened due to the recurrence of a respiratory infection. During the initial exacerbation, his tidal volume was significantly lower during sleep (378.9 ± 72.9mL) than while awake (446.5 ± 63.3mL). A ventilator that allows ventilation to be maintained by automatically adjusting the inspiratory force to within an acceptable range was attached in average volume-assured pressure support mode, improving his sleep-related hypoventilation, which is often associated with the use of the Respironics V60 Ventilator. Polysomnography performed while our patient was on noninvasive positive pressure ventilation revealed obstructive sleep apnea syndrome (apnea-hypopnea index = 14), suggesting that his chronic obstructive pulmonary disease was complicated by obstructive sleep apnea syndrome. In cases such as this, in which patients with severe acute respiratory failure requiring full-time noninvasive positive pressure ventilation therapy also show sleep-disordered breathing, different ventilator settings must be used for waking and sleeping. On such occasions, the Respironics V60 Ventilator, which is equipped with an average volume-assured pressure support mode, may be useful in improving gas exchange and may achieve good patient compliance, because that mode allows ventilation to be maintained by automatically adjusting the inspiratory force to within an acceptable range whenever ventilation falls below target levels.

Nocturnal hypoventilation in Down syndrome children with or without sleep apnea

Abstract: Background There is a high prevalence of obstructive sleep apnea (OSA) in children with Down syndrome (DS), sometimes associated with alveolar hypoventilation. Objective To compare transcutaneous partial pressure of carbon dioxide (PtcCO2 ) and pulse oximetry (SpO2 ) in children with DS and in control children with OSA. Patients and methods This retrospective case-control study involved children followed in Trousseau Hospital (Paris) Sleep Center. Polysomnography (PSG) recordings and clinical files of children with DS were reviewed to identify clinical signs of OSA and comorbidities associated with DS. Controls were children who presented with OSA of ENT origin without other comorbidities (exceptions: two overweight, one obese, and three with well-controlled asthma). DS subjects and controls were matched for age and apnea hypopnea index. Results There were 28 children in each group. Mean PtcCO2 during sleep was significantly higher in patients with DS compared to controls (44 mm Hg vs 42 mm Hg, P = .001). Five (21%) patients with DS met the American Academy of Sleep medicine criteria for hypoventilation, compared to one (4%) in the control group. The mean PtcO2 during sleep was significantly lower in patients with DS (77 mm Hg vs 82 mm Hg, P = .003). Conclusions This is the first study to compare nocturnal gas exchange in children with DS to a control group of children with similar OSA. Our data demonstrate that children with DS have increased PtcCO2 regardless of the presence of OSA and its severity. This may be due to respiratory muscle hypotonia and/or ventilatory control alteration in patients with DS.

102 Ventilatory response to hyperoxia in newborn mice heterozygous for the transcription factor Phox2b

Abstract: Introduction The transcription factor Phox2b is a master regulator of the noradrenergic phenotype and of dl neuronal relays of the autonomic medullary reflex pathways including peripheral chemoreceptors and their afferent viscerai pathways. Heterozygous mutations of Phox2b have been found in a high proportion of patients with Central Congenitd Hypoventilation Syndrome (CCHS), a rare autosomal dominant syndrome characterized by hypoventilation during sleep, and impaired ventilatory responses to hypercapnia and hypoxia. We previously showed that Phox2b+/- mutant mice showed a blunted response to CO2 [l], and a large increase in sleep apnea total time [2]. However, the hyperpneic response to hypoxia was normd [l]. The aim of this study was to examine chemosensitivity to 0 2 in Phox2B+/- pups using an hyperoxic test. Methods 136 wild-type and mutant two-day old pups were exposed to two hyperoxic tests (12 min air followed by 3 min 02), followed by 12 min air. Breathing variables and apneas were measured noninvasively using whole body flow plethysmography. We evaluated the ventilatory response to hyperoxia based on the maximal VE decline, i.e., the minima VE value (min VE) over the 3 min of O2 exposure expressed as the percentage of the baseline level. Results . Conclusion Sensitivity to O 2 was not impaired in Phox2B+/- newborn pups, in line with previous results showing their normal hyperpneic response to hypoxia, and in contrast with CCHS. However, hyperoxia caused a sustained ventilatory depression in mutant pups, suggesting that disruption of Phox2B impaired activatory processes of breathing. This latter effect may contibute to sleep-related respiratory disorders in CCHS.

Cardiovascular responses to verapamil and nifedipine in hypoventilated and hyperventilated rats.

Abstract: 1. The influence of hypoventilation or hyperventilation on blood pressure and pulse rate responses to verapamil and nifedipine was studied in chloralose-anaesthetized rats. 2. Artificial ventilation with room air at a fixed volume of 10 ml kg-1 successfully induced combinations of hypoxaemia, hypercarbia and acidosis at a ventilator rate of 37 strokes min-1 and of hyperoxaemia, hypocarbia and alkalosis at 160 strokes min-1. 3. Hypoventilation caused significant decreases in both the blood pressure and pulse rate, whereas hyperventilation produced significant increases in these parameters. 4. In the controls, intravenous injections of graded doses of either verapamil or nifedipine caused dose-dependent decreases in mean blood pressure. The effects on pulse rate were not marked. 5. The hypotensive effects of verapamil were significantly more intense in hyperventilated rats, whereas those of nifedipine were significantly less pronounced in hypoventilated animals. The hypoventilated rats exhibited a significant dose-dependent decrease in pulse rate in response to verapamil administration. 6. It is concluded that cardiovascular responses to verapamil, nifedipine and probably other calcium antagonists are altered in the presence of blood gas abnormalities.