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

Six young male patients with grade I (mild) myotonic dystrophy and a complaint of excessive daytime sleepiness were studied during wakefulness and sleep. Pulmonary function tests during wakefulness showed evidence of mild abnormality related to respiratory muscle weakness. During sleep, some patients developed a sleep apnea syndrome with high sleep Apnea Indices. There was no relation between hypoxic and hypercapnic ventilatory responses during wakefulness and sleep Apnea Indices. But hypoxemia and hypercapnia worsened considerably during REM sleep. Myotonic dystrophy patients with sleep apnea presented increased pulmonary and systemic arterial pressures during sleep. It was also during sleep that arrhythmias were observed.
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PMID:Respiratory and hemodynamic study during wakefulness and sleep in myotonic dystrophy. 22 21

Patients with myotonic dystrophy often develop respiratory failure caused by alveolar hypoventilation. Abnormalities in the ventilatory response to hypoxia and hypercapnia may explain this phenomenon. Accordingly, hypoxic and hypercapnic responses were measured in seven patients with myotonic dystrophy who had only mild respiratory muscle weakness. Hypoxic response was significantly reduced, while hypercapnic response was affected more irregularly. It is possible that the high incidence of respiratory failure in such patients is related to decreased hypoxic ventilatory response, occurring because of an underlying neurogenic deficit.
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PMID:Ventilatory response in myotonic dystrophy. 56 10

Two hundred ninety patients undergoing carotid endarterectomy were reviewed. From 1968 to 1972, 188 patients had carotid endarterectomy under general anesthesia with use of a shunt and hypercarbia. Stump pressures were not recorded in this group. There were three deaths, three postoperative hemiplegias and two complications of transient limb weakness. From 1973 to 1975, 102 patients were operated on under local anesthesia with systemic Innovar and Sublimaze, normocarbia and intra-operative assessment of stump pressure. In this group there was one death, no hemiplegia, and no complications of transient limb weakness. Twenty of the 102 were shunted either on the basis of stump pressure or the loss of motor ability or consciousness on carotid clamping. Those shunted had stump pressures ranging from 10 to 70 mm Hg with a mean of 20 while those not shunted had stump pressures ranging from 20 to 85 mm Hg with a mean of 53 mm Hg. Five patients lapsed into unconsciousness despite internal carotid stump pressures of 30, 30, 34, 36 and 70 mm Hg respectively, thus requiring intraoperative shunting. This experience seriously questions the reliability of carotid stump pressure as the sole determinant to identify those patients who require intraoperative shunting. We have come full circle, back to operation under local anesthesia, since intraoperative assessment of the patient's motor ability and consciousness alone provide the only absolute criteria for assessing the need for intraoperative shunting. Since the operation can be performed with greater technical efficiency without a shunt and without the potential complications of shunting itself, it behooves the surgeon to have a reliable method of knowing when it is not required.
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PMID:Improved results with carotid endarterectomy. 88 76

Four patients with ptosis, external ophthalmoplegia, and ragged-red fibers on muscle biopsy were found to have decreased ventilatory responses to hypoxia and hypercapnia. Respiratory muscle weakness was not responsible for these findings since these responses were normal in muscle disease control patients. An altered metabolic state also can cause diminished ventilatory response, but overall oxygen consumption data in the ragged-red fiber patients were normal. The decreased ventilatory responses may be clinically significant because two of the ragged-red fiber patients had episodes suspicious of hypoventilation with poor response to hypoxia.
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PMID:Depressed ventilatory response in oculocraniosomatic neuromuscular disease. 94 69

In 20 patients with chronic renal failure on a hemodialysis with acetate-containing dialysing fluid gasometric, ventilation and breathing patterns disturbances were determined. The loss of CO2 in the dialysate is attributed the major cause of hypoxemia due to alveolar hypoventilation. Hemodialysis with bicarbonate-containing dialysate can be performed in the absence of any change in ventilation and PaO2 despite a systemic alkalosis. Hyperventilation during HD with high concentration of bicarbonate indicate that changes in CO2 tension in the pulmonary circulation can lead to a change in minute ventilation due to the presence of slowly adapting pulmonary chemoreceptors. In patients with low respiratory response, respiratory muscle weakness intensified additionally by hypercapnia may explain this phenomenon.
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PMID:[Effect of carbon dioxide (CO2) pressure on minute ventilation, parameters of gas exchange and blood gases during hemodialysis using fluid containing acetate and bicarbonate buffers]. 143 19

Unlike individuals with comparable degrees of respiratory muscle weakness from other causes, quadriplegic patients have a blunted ventilatory and P0.1 response to hypercapnia. This suggests that the diminished response in quadriplegia is due, in part, to an alteration in respiratory drive. We measured the hypercapnic response in 9 subjects with chronic quadriplegia (Q) and 8 normal controls (N). Ventilatory muscle strength, maximum voluntary ventilation (MVV), and lung volumes were measured in all subjects. The ventilatory response (HCVR) in Q was significantly less than in N (0.73 +/- 0.37 vs 2.95 +/- 0.4 L.min-1.mmHg-1; P less than 0.001), even when normalized for indices of respiratory muscle performance (e.g., vital capacity, MVV). There was no significant change in the HCVR in Q after the administration of naloxone. We also serially studied 2 subjects with acute quadriplegia, and found that despite progressive improvement in respiratory muscle performance, there was no accompanying increase in the response to hypercapnia. These data suggest that muscle weakness alone cannot explain the blunted hypercapnic response in quadriplegia, and are consistent with the hypothesis that these subjects have a reduced ventilatory drive.
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PMID:Ventilatory and P0.1 response to hypercapnia in quadriplegia. 151 90

A 36-year-old woman with myotonic dystrophy presented with generalized weakness and daytime somnolence. Arterial blood gas analysis revealed significant hypoxemia and hypercapnia, and a polysomnogram revealed additional oxygen desaturation during sleep. For nocturnal ventilatory assistance, the patient received positive-pressure ventilation via a nasal mask. This mode of ventilation produced marked improvement in the patient's nocturnal hypoxemia.
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PMID:The use of mechanical ventilation via a nasal mask in myotonic dystrophy. 155 16

Respiratory complications occur in advanced multiple sclerosis (MS) but may also complicate acute relapses earlier in the disease. We present 19 patients with MS who developed respiratory complications at a mean of 5.9 (range 1-12) yrs after the onset of neurological symptoms. Fourteen patients developed severe respiratory insufficiency presenting with a combination of reduced forced vital capacity (FVC), hypoxaemia or hypercapnia (12 patients) and respiratory arrest (four patients). Two patients presented with apneustic breathing, one with paroxysmal hyperventilation, one with obstructive sleep apnoea and one with bulbar weakness leading to aspiration pneumonia. Respiratory muscle weakness was a major factor in 14 patients (predominantly diaphragm involvement in six), bulbar weakness in seven patients, impaired voluntary control in three and impaired automatic control in three. Twelve patients received mechanical respiratory support of whom seven have subsequently died. The methods of support used were intermittent positive pressure ventilation (nine patients), iron lung (three), cuirass (two) and rocking bed (one). Six patients were maintained on respiratory support until they died after intervals varying from 24 h to 6 yrs (mean 17.7 mths). Five patients received temporary ventilation for between 6 d and 42 d: of these four remain alive at up to 4 yrs and one died after 16 yrs. One patient remains on domiciliary nasal intermittent positive pressure ventilation (IPPV) after 1 yr.
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PMID:Respiratory involvement in multiple sclerosis. 160 78

We reported a case of Kearns-Sayre syndrome with impaired respiratory regulation. A 55-year-old male was admitted to our hospital complaining of chronic progressive external ophthalmoplegia, limb muscle weakness and dyspnea. On admission, because arterial blood gas analysis showed marked alveolar hypoventilation, ventilatory response was measured and diminished chemosensitivity to both hypoxia and hypercapnia was found. His vital capacity and forced expiratory volume in 1 second were slightly decreased, and a chest X-ray film revealed a moderate degree of elevation of the bilateral diaphragm. Therefore, we considered that the diminished response to hypoxia and hypercapnia in this case was caused by an impairment of the respiratory center, as well as chemoreceptors and also the presence of respiratory muscular weakness.
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PMID:[A case of Kearns-Sayre syndrome with impaired respiratory regulation]. 175 13

The purpose of this study was to assess the strength of the respiratory muscles in 12 infants with neuromuscular disease (age range: 0.17-2.08 years) by measuring the maximal inspiratory and expiratory airway pressures (Pimax and PEmax) during crying efforts. Infants were divided into two groups according to their respiratory history. Group A included six infants in stable condition without clinical evidence of respiratory abnormalities, and Group B included six infants with severe generalized muscle weakness and previous respiratory failure. The infants in Group B had been weaned from mechanical ventilation 6 to 14 days before being studied. For infants of Group A, Pimax and PEmax values were 77 +/- 28 cmH2O and 62 +/- 18 cmH2O, respectively; for infants of Group B, they were 38 +/- 8 cmH2O and 34 +/- 8 cmH2O, respectively. A positive correlation was found between PEmax and body mass percentile. No infant had hypercapnia at the time of the study, and Pao2 values in infants of Group B were significantly lower than those of Group A. These results suggest that measurements of airway pressures during crying may provide an index of respiratory muscle strength in infants with generalized muscle weakness.
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PMID:Airway pressures during crying: an index of respiratory muscle strength in infants with neuromuscular disease. 185 14


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