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.

The Use of DCEEG to Estimate Functional and Metabolic State of Nervous Tissue of the Brain at Hyper- and Hypoventilation

Abstract: A pilot study has been made of the simultaneous DC potential and total slow electrical activity changes during modeling various metabolic and functional states of the human brain. The multi-electrode DCEEG recordings have been performed during the hyperventilation (frequent deep one-minute long breathing motions) and the hypoventilation (voluntary breath holding). It has been shown that the ischemic state occurring in hyperventilation is accompanied by the negative shift of DC potential and increase in the EEG rhythms amplitude. A distention of brain vessels during hypoventilation (voluntary breath-hold) and an improvement of blood supply and thus improvement of vital and functional state of neurons gave rise to an increase in the EEG rhythm amplitude too, though against a background of a positive DC-potential shift. Obtained results are considered with context the generation of the qualitatively different functional states of brain cells during hyper- and hypoventilation which is reflected in their resting potential and activity. The conducted study show the prospects for DCEEG and the method we used for DCEEG data processing to understand the character of functional and metabolic changes in the nervous tissue.

Nonrecurring transient cortical blindness after coronary angiography: a role for hypoventilation and hypercarbia?

Abstract: A 73-year-old morbidly obese patient suffered cortical blindness following coronary angiography. Symptoms rapidly resolved and did not recur following a repeated procedure. Hypoventilation due to narcotics with subsequent hypercarbia and blood-brain barrier breaching may be implicated in the pathogenesis of this complication.

Congenital Central Hypoventilation Syndrome (CCHS) and PHOX2B Mutations

Abstract: Publisher Summary Congenital central hypoventilation syndrome (CCHS) is characterized by disordered respiratory control and autonomic nervous system (ANS) dysregulation. Disordered respiratory control, as demonstrated by absent/severely attenuated ventilatory, behavioral, and arousal responses to endogenous/exogenous hypoxemia/hypercarbia occurring at rest or in activities of daily living results in severe physiologic compromise. To clarify, PHOX2B encodes a highly conserved homeodomain transcription factor which plays a key role in early embryologic development of ANS reflex circuits in mice and has expression in both central autonomic neuron circuits and peripheral neural crest derivatives in the human embryo and in the rodent. A relationship between the PHOX2B genotype and need for continuous ventilatory dependence has been reported. Individuals with the 20/25 genotype have the mildest hypoventilation, typically requiring ventilatory support during sleep only. However, a few frameshift mutations located early in exon 3 of PHOX2B have been inherited and are variably penetrant, suggesting that frameshifts in this area may produce a milder functional deficit than other frameshift mutations.

Extreme obesity in the intensive care unit: the malignant obesity hypoventilation syndrome.

Abstract: Extreme obesity is currently a common medical condition. It is defined as having a body mass index (BMI) of >40 kg/m and is associated with an increased risk of mortality. A review of the clinical literature has shown that extreme obese patients are commonly admitted to the intensive care unit (ICU) for obstructive airway disease, pneumonia, and sepsis. A recent study found that patients with a BMI of >40 kg/m required greater mechanical ventilation and, therefore, a corresponding prolonged stay in the ICU. What are the other factors affecting the outcome of extreme obese patients in the ICU? In this issue of the Journal of Intensive Care Medicine, a new obesity-related condition among patients in the ICU with obesity hypoventilation syndrome (OHS) is now being described. The OHS is defined as the triad of obesity, daytime hypoventilation, and sleep-disordered breathing in the absence of an alternative neuromuscular, mechanical, or metabolic explanation for the hypoventilation episodes. Given this definition, a subtype condition has been identified in the extreme obese patients who had hypercapnic respiratory failure and multiorgan system dysfunction related to obesity, labeled as malignant obesity hypoventilation syndrome (MOHS). Marik and Desai coined this new term using a retrospective electronic chart review of 61 patients admitted to the ICU with a BMI of >40 kg/m and a PaCO2 greater than 45 mm Hg in patients admitted with hypercapnic respiratory failure. Supporting the description of MOHS, a statistical analysis of the documentation from this study confirmed the presence of multisystem disorder in extreme obesity by finding that 86% of the patients had congestive heart failure treated with diuretics, 71% had left ventricular failure, 61% had left ventricular diastolic dysfunction, 77% had pulmonary hypertension above 45 mm Hg, 90% had essential hypertension, and 64% had abnormal liver function tests and diagnosed with nonalcoholic steatohepatitis. Moreover, this retrospective study showed that based on the clinical documentation, these patients fit the clinical criteria for OHS, however, only 3 were diagnosed with this condition and the remaining (75%) were diagnosed with and treated for chronic obstructive lung disease (COPD). A primary question that arises after reading the study of Marik and Desai is ‘‘Are patients with extreme obesity admitted to the ICU with a diagnosis of COPD/asthma being misdiagnosed when in fact they could have unrecognized OHS?’’ It is known that patients with extreme obesity statistically have hypercapnic respiratory failure that increases the length of stay in the ICU due to prolonged necessity for mechanical ventilation. It is also well known that hypoventilation and oxygen disturbances are related to obesity even if there is no intrinsic lung disease. Therefore, mechanical ventilation in the extreme obese patient is one of many challenges clinicians face since the increase in the prevalence of obesity, with a corresponding increase in ICU admissions. It is very concerning that only 3 of 61 patients had a confirmed diagnosis of OHS. More interestingly, the management of extreme obese patients with bilevel positive airway pressure (BiPAP) in this study failed in 23% of the patients, thus requiring mechanical ventilation. This was an unexpected finding which highlights again the challenge of managing respiratory failure and the use of mechanical ventilation in extremely obese patients. What would have happened if OHS was part of the medical history of these patients admitted to the ICU? It is well known that extremely obese patients with concomitant untreated obstructive sleep apnea (OSA) present