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.

Sleep and Breathing in Patients With the Prader-Willi Syndrome

Abstract: The Prader-Willi syndrome is characterized by infantile hypotonia, early childhood obesity, mental deficiency, short stature, small hands and feet, and hypogonadism. Many patients also have hypersomnolence, experience daytime hypoventilation, and subsequently die prematurely of cardiorespiratory failure. Hypersomnolence and daytime hypoventilation are also common occurrences in the sleep apnea syndrome. For a better understanding of the relationship of sleep to the features of the Prader-Willi syndrome, we retrospectively reviewed five patients (two adults, one adolescent, and two children) with this syndrome who underwent polysomnography. All patients were obese; they had hypersomnolence and daytime hypoxemia, and they snored. In all patients, the apnea plus hypopnea index was less than 10 episodes per hour of sleep. During rapid eye movement sleep, nonapneic reductions in oxyhemoglobin saturation were detected in one adult and in one child. Despite the presence of morbid obesity and a history of snoring, patients with Prader-Willi syndrome seem to have only mild sleep-disordered breathing.

Effect of sleep stage on breathing in children with central hypoventilation

Abstract: The early literature suggests that hypoventilation in infants with congenital central hypoventilation syndrome (CHS) is less severe during rapid eye movement (REM) than during non-REM (NREM) sleep. However, this supposition has not been rigorously tested, and subjects older than infancy have not been studied. Given the differences in anatomy, physiology, and REM sleep distribution between infants and older children, and the reduced number of limb movements during REM sleep, we hypothesized that older subjects with CHS would have more severe hypoventilation during REM than NREM sleep. Nine subjects with CHS, aged (mean ± SD) 13 ± 7 yr, were studied. Spontaneous ventilation was evaluated by briefly disconnecting the ventilator under controlled circumstances. Arousal was common, occurring in 46% of REM vs. 38% of NREM trials [not significant (NS)]. Central apnea occurred during 31% of REM and 54% of NREM trials (NS). Although minute ventilation declined precipitously during both REM and NREM trials, hypoventilation was less severe during REM (drop in minute ventilation of 65 ± 23%) than NREM (drop of 87 ± 16%, P = 0.036). Despite large changes in gas exchange during trials, there was no significant change in heart rate during either REM or NREM sleep. We conclude that older patients with CHS frequently have arousal and central apnea, in addition to hypoventilation, when breathing spontaneously during sleep. The hypoventilation in CHS is more severe during NREM than REM sleep. We speculate that this may be due to increased excitatory inputs to the respiratory system during REM sleep.

Nocturnal respiratory failure as an indication of noninvasive ventilation in the patient with neuromuscular disease.

Abstract: Patients with neuromuscular disease may suffer from nocturnal respiratory failure despite normal daytime respiratory function. The physiological reduction in muscle tone during sleep may be life-threatening in a patient with impaired muscle strength. Nocturnal respiratory failure may occur in patients with the postpolio syndrome, amyotrophic lateral sclerosis, myasthenia gravis, myotonic dystrophy, and muscular dystrophy. Diagnosis of obstructive, central and mixed apneas, hypopneas, and hypoventilation is best made using polysomnography. Therapeutic options include noninvasive ventilation such as continuous positive airway pressure, bilevel positive airway pressure, intermittent positive pressure ventilation and, rarely, tracheostomy, oxygen, or protriptyline. Evaluation by a sleep specialist should be initiated in any neuromuscular patient with nocturnal symptoms such as air hunger, intermittent snoring or breathing, orthopnea, cyanosis, restlessness, and insomnia. Daytime symptoms may include morning drowsiness, headaches and excessive daytime sleepiness. Polycythemia, hypertension, and signs of heart failure may also be seen. Effective treatment is available, and may improve the quality of life, and possibly increase survival.

Bedside adjustment of proportional assist ventilation to target a predefined range of respiratory effort.

Abstract: Objectives: During proportional assist ventilation with load-adjustable gain factors, peak respiratory muscle pressure can be estimated from the peak airway pressure and the percentage of assistance (gain). Adjusting the gain can, therefore, target a given level of respiratory effort. This study assessed the clinical feasibility of titrating proportional assist ventilation with load-adjustable gain factors with the goal of targeting a predefined range of respiratory effort. Design: Prospective, multicenter, clinical observational study. Settings: Intensive care departments at five university hospitals. Patients: Patients were included after meeting simple criteria for assisted mechanical ventilation. Interventions: Patients were ventilated in proportional assist ventilation with load-adjustable gain factors. The peak respiratory muscle pressure, estimated in cm H 2 O as (peak airway pressure – positive end-expiratory pressure) × [(100 – gain)/gain], was calculated from a grid at the bedside. The gain adjustment algorithm was defined to target a peak respiratory muscle pressure between 5 and 10 cm H 2 O. Additional recommendations were available in case of hypoventilation or hyperventilation. Results: Fifty-three patients were enrolled. Median time spent under proportional assist ventilation with load-adjustable gain factors was 3 days (interquartile range, 1–5). Gain was adjusted 1.0 (0.7–1.8) times per day, according to the peak respiratory muscle pressure target range in 91% of cases and because of hypoventilation or hyperventilation in 9%. Thirty-four patients were ventilated with proportional assist ventilation with load-adjustable gain factors until extubation, which was successful in 32. Eighteen patients required volume assist-controlled reventilation because of clinical worsening and need for continuous sedation. One patient was intolerant to proportional assist ventilation with load-adjustable gain factors. Conclusions: This first study assessing the clinical feasibility of titrating proportional assist ventilation with load-adjustable gain factors in an attempt to target a predefined range of effort showed that adjusting the level of assistance to maintain a predefined boundary of respiratory muscle pressure is feasible, simple, and often sufficient to ventilate patients until extubation. (Crit Care Med 2013;41:0–0)

Managing acute respiratory decompensation in the morbidly obese

Abstract: Morbid obesity adversely affects respiratory physiology, leading to reduced lung volumes, decreased lung compliance, ventilation perfusion mismatch, sleep-disordered breathing and the impairment of ventilatory control, and neurohormonal and neuromodulators of breathing. Therefore, morbidly obese subjects are at increased risk of various pulmonary complications that can present either acutely or chronically. Respiratory failure is one of the most common pulmonary complications related to morbid obesity. Both acute hypoxaemic and hypercapnic respiratory failure are more common among obese patients. The management pathway of respiratory failure depends, to a large extent, on the underlying cause, primarily due to the diversity of the underlying triggering diseases, the pathophysiology and the prognosis associated with each disease. Morbidly obese patients with hypoventilation have an increased risk of acute hypercapnic respiratory failure. Early diagnosis of this disorder and the application of non-invasive ventilation in this group of patients have been shown to improve respiratory parameters, decrease the need for invasive mechanical ventilation and improve survival. Invasive ventilation remains the last life-saving procedure in patients with respiratory failure who do not respond to non-invasive measures. However, due to the abnormal respiratory physiology in obese patients, special precautions are required during intubation, mechanical ventilation and weaning.