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Query: UMLS:C0020440 (hypercapnia)
 7,939 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied ventilatory responsiveness to hypoxia and hypercapnia in anesthetized cats before and after exposure to 5 atmospheres absolute O2 for 90-135 min. The acute hyperbaric oxygenation (HBO) was terminated at the onset of slow labored breathing. Tracheal airflow, inspiratory (TI) and expiratory (TE) times, inspiratory tidal volume (VT), end-tidal PO2 and PCO2, and arterial blood pressure were recorded simultaneously before and after HBO. Steady-state ventilation (VI at three arterial PO2 (PaO2) levels of approximately 99, 67, and 47 Torr at a maintained arterial PCO2 (PaCO2, 28 Torr) was measured for the hypoxic response. Ventilation at three steady-state PaCO2 levels of approximately 27, 36, and 46 Torr during hyperoxia (PaO2 450 Torr) gave a hypercapnic response. Both chemical stimuli significantly stimulated VT, breathing frequency, and VI before and after HBO. VT, TI, and TE at a given stimulus were significantly greater after HBO without a significant change in VT/TI. The breathing pattern, however, was abnormal after HBO, often showing inspiratory apneusis. Bilateral vagotomy diminished apneusis and further prolonged TI and TE and increased VT. Thus a part of the respiratory effects of HBO is due to pulmonary mechanoreflex changes.
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PMID:Effects of acute hyperbaric oxygenation on respiratory control in cats. 260 41

A two-year-old boy with a history of slow growth, snoring during sleep and adenoid hypertrophy underwent adenoidectomy and transtympanic drainage under general anesthesia. Immediately after extubation, severe inspiratory stridor and shallow labored breathing began and persisted over a period of two hours, in spite of corticoid administration and oxygen therapy. The signs receded partially when the patient was seated and with a mandibular traction maneuver. As symptoms persisted, foreign body obstruction was ruled out by examination of the cavum and upper airway under general anesthesia and with orotracheal intubation. The patient was transferred to the pediatric intensive care unit, where he remained intubated for 18 hours. After extubation, stridor and shallow labored breathing reappeared but gradually receded as the residual effects of sedation disappeared. The parents mentioned symptoms suggestive of obstructive sleep apnea syndrome (OSAS) occurring since the boy was 6 months old and that had worsened in recent months. OSAS in children is characterized by intermittent obstruction of the upper airway during sleep, causing snoring and periods of apnea/hypopnea that lead to hypoxemia and hypercapnia. The most frequent cause is hypertrophy of the adenoid and tonsils, and the treatment of choice is adenotonsillectomy, although the risk of postoperative respiratory distress in such children is high. It is important to rule out OSAS in children who are candidates for adenotonsillectomy so that such patients are not scheduled for ambulatory surgery, but rather given adequate postoperative monitoring and treatment.
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PMID:[Compromized postadenoidectomy respiration in a child with obstructive sleep apnea syndrome]. 949 65

Dyspnea is the unpleasant awareness of breathing while healthy persons will hardly sense their own breath at rest. Dyspnea is comparable to pain because both caution the organism that will activate protective mechanisms to avoid further damage. Dyspnea results from central nervous processing of respiratory feed back signals. Feed back from respiratory muscles, the chest wall, the airways and the lung reach the brain while partial pressure of oxygen and carbon dioxide is continuously monitored and arterial blood gases are permanently stabilized. Sensation of breathlessness depends on its origin. Main qualities of dyspnea include air hunger during hypercapnia, laboured breathing during increased minute ventilation and chest tightness in asthma. During chronic dyspnea, respiratory control aims for a new breathing pattern that will ease breathlessness. Since respiratory control includes both autonomic regulation and cortical modulation of breathing, voluntarily guided respiration can be employed to influence other autonomic regulated systems and pain perception.
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PMID:[Breathlessness: different causes and qualities of dyspnea]. 1955 55

Lung contusion is an entity involving injury to the alveolar capillaries, without any tear or cut in the lung tissue. This results in accumulation of blood and other fluids within the lung tissue. The excess fluid interferes with gas exchange leading to hypoxia. The pathophysiology of lung contusion includes ventilation/perfusion mismatching, increased intrapulmonary shunting, increased lung water, segmental lung damage, and a loss of compliance. Clinically, patient's presents with hypoxiemia, hypercarbia and increase in laboured breathing. Patients are treated with supplemental oxygen and mechanical ventilation whenever indicated. Treatment is primarily supportive. Computed tomography (CT) is very sensitive for diagnosing pulmonary contusion. Pulmonary contusion occurs in 25-35% of all blunt chest traumas.
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PMID:Lung Contusion: A Clinico-Pathological Entity with Unpredictable Clinical Course. 2716 15