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.

Respiratory muscle assessment in motor neurone disease.

Abstract: In this issue, Hadjikoutis and Wiles correctly identify that respiratory failure is the commonest cause of death in Motor Neurone Disease (MND)1 and discuss the use of venous bicarbonate and chloride to assess respiratory function.2 The study's finding that this domiciliary investigation can provide prognostic information regarding the respiratory status of MND patients is interesting, and it is useful to consider its place amongst the many tests of respiratory muscle and ventilatory function that are available. Respiratory muscle weakness is a common feature of MND and is often present at diagnosis.3 Although such weakness is usually asymptomatic at this stage, respiratory failure can be the presenting feature of MND.4,,5 Respiratory muscle strength continues to deteriorate during the course of the disease,6,,7 with symptoms developing insidiously, eventually leading to respiratory failure and, if untreated, death. Due to the impaired mobility of the patients, symptoms of hypoventilation are initially subtle and depend on the pattern of respiratory muscle weakness. If the diaphragm is predominantly involved, orthopnoea will be a major symptom, due to the weak diaphragm failing to counter the gravitational displacement of the abdominal contents into the thorax when the patient lays flat. More global respiratory muscle weakness will cause exertional dyspnoea; however, if disability due to limb weakness limits physical activity, a history of breathlessness during speech, dressing or eating must be sought. Hypoventilation (i.e. hypercapnia) occurs first during sleep.8 This is particularly the case in REM sleep, as a result of the reduction of intercostal and accessory muscle activity, leaving only a weakened diaphragm to support ventilation.9 In many patients, sleep‐related hypoventilation occurs before resting dyspnoea, and abnormal daytime arterial blood gases develop. This may lead to a reduction in the time spent in REM or an increase …

New modes of mechanical ventilation in the preterm newborn: evidence of benefit.

Abstract: The introduction of modern mechanical ventilation in neonatal medicine in the 1960s was followed shortly thereafter by its use in premature infants with hyaline membrane disease. Most premature infants born before 30 weeks’ gestation receive some form of respiratory support, particularly those with fewer weeks of gestation.1 Although mechanical ventilation is frequently a life-saving therapy, its use increases the risk of lung injury, particularly in preterm infants in whom the incidence of bronchopulmonary dysplasia (BPD) remains high.2 Before the current generation of neonatal ventilators, conventional mechanical ventilation (CMV) was provided mainly with time-cycled pressure limited (TCPL) ventilators developed from adaptation of Ayre’s T piece.3 This method, also known as intermittent mandatory ventilation (IMV), was and probably still is in many centres, the most common mode of ventilation. During IMV mechanical breaths of fixed duration are delivered at predetermined time intervals. This frequently leads to asynchrony depending on the phase of the spontaneous breath when these IMV breaths are delivered. Inspiratory asynchrony occurring when a mechanical breath is delivered at the end of and extends beyond spontaneous inspiration can produce an inspiratory hold that limits the spontaneous respiratory rate or results in excessive lung inflation. Expiratory asynchrony occurring when a mechanical breath is delivered during exhalation can delay lung deflation and elicit active expiratory efforts against positive pressure producing large fluctuations in intrathoracic pressure. Asynchrony can affect gas exchange, and has been linked to increased risk of air leaks4 5 and intraventricular haemorrhage (IVH).6 As volume monitoring was lacking in most IMV devices, it was difficult to detect excessive lung inflation, gas trapping or hypoventilation. Advances in ventilator technology allowed mechanical breaths to be synchronised with the onset of spontaneous inspiration. This was achieved by using signals derived from spontaneous respiratory activity. Synchronisation was also extended …