Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020440 (hypercapnia)
 7,939 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Surgical closure of patent ductus arteriosus (PDA) and perioperative time have been proposed as conditions of increased risk of peri-intraventricular hemorrhage (PVH-IVH) in preterm infants. We examined by pre- and postoperative ultrasound (US) scan 15 low birth-weight neonates who underwent PDA ligation within the first two weeks of life. They were assessed with regard to clinical state, perioperative management and development of PVH-IVH. Fourteen did not show onset or extension of intracranial hemorrhage in the immediate postoperative period. One patient developed a wide III grade IVH in the 24 perioperative hours. His conditions were particularly severe, suggesting that many factors such as acidosis, hypoxia, hypercapnia and hypotension might have combined to lead to hemorrhage. We conclude that PDA ligation is not likely to increase the risk of PVH-IVH per se.
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PMID:[The relationship between ligation of the ductus arteriosus and intracranial hemorrhage in preterm infants]. 224 53

During wet dives in a hyperbaric chamber to 6.8 atm abs (690 kPa), air breathing subjects were experimentally exposed to external breathing resistance. Two of them were, unbeknownst to themselves, severely incapacitated. In the first incident the subject had been exercising for 25 min (end-tidal PCO2 60-65 mmHg, 7.3-8.0 kPa) when the breathing resistance was rapidly increased from low to very high (requiring pressure swings of 80 cmH2O, 8 kPa, peak to peak). He functioned normally (end-tidal PCO2 72 mmHg, 9.6 kPa) for about 100 s but 20 s later he was confused and irrational. After being extracted from the water (end-tidal PCO2 above 90 mmHg, 12 kPa), he lost consciousness for about 60 s. In the second incident the subject was exercising and breathing against a high resistance (pressure swings of 50-55 cmH2O, 5.0-5.6 kPa). His end-tidal PCO2 was high (65-68 mmHg, 8.7-9.3 kPa) throughout the exercise period, and after 24 min he reported mild dyspnea. A few seconds later he became confused. In other experiments both subjects voluntarily terminated experiments when the breathing resistance became overwhelming. These 2 subjects generally had high end-tidal PCO2 levels, but 1 other subject with end-tidal PCO2 levels in the same range never experienced any problems. These incidents indicate that severe hypercapnia does not necessarily correlate with dyspnea and that severe disturbances in mental function due to hypercapnia can develop suddenly when high breathing resistance is encountered in diving.
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PMID:CO2 retention with minimal symptoms but severe dysfunction during wet simulated dives to 6.8 atm abs. 228 42

We report a study of an adult with a maltase acid deficiency myopathy. A restrictive respiratory syndrome due to respiratory muscle weakness is associated with paralysis of other muscular groups. In 1982 the patient presented with an alveolar hypoventilation, and mechanical ventilation was required after acute respiratory failure. The patient has received nocturnal mechanical ventilation by tracheostomy at home for 5 years. His clinical status gradually improved in parallel to amelioration of his respiratory condition. Functional respiratory tests improved: initial hypoxia-hypercapnia disappeared, vital capacity increased. The possible mechanisms underlying the improvement are discussed. Increase in pulmonary compliance is an argument to explain the functional improvement observed. Ventilatory response to carbon dioxide was abnormal whereas the ventilatory response to exercise and maxima minute ventilation test were normal. Results are consistent with a respiratory control impairment. The role of mechanical ventilation is difficult to assess in the improvement we observed.
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PMID:Adult maltase acid deficiency myopathy: treatment with long-term home mechanical ventilation. 305 36

Amiloride (10(-3) M), a Na+-H+ countertransport inhibitor, infused into the cisterna magna (10 microliter/min for 40 min) of ketamine-xylazine-anesthetized rabbits decreased the cerebrospinal fluid (CSF) HCO3- response to 3 h of hypercapnia [arterial PCO2 (PaCO2) = 60 Torr] by 21.6% (mean delta CSF [HCO3-]/delta PaCO2 0.232 vs. 0.296 mmol.l-1.Torr-1, P less than 0.05). Diethyl pyrocarbonate (DEPC, 10(-3) M), a histidine-blocking agent, infused into the cisterna magna decreased the CSF HCO3- response to hypercapnia by 25.3% (mean delta CSF [HCO3-]/delta PaCO2, 0.230 vs. 0.308 mmol.l-1.Torr-1, P less than 0.02). DEPC is known to inhibit the ventilatory response to hypercapnia (E. Nattie. Respir. Physiol. 64: 161-176, 1986) by a direct effect at the ventrolateral medulla (E. Nattie. J. Appl. Physiol. 61: 843-850, 1986). In this study amiloride had no significant effect on the ventilatory response to hypercapnia. The interpretation is that a Na+-H+ countertransport protein, perhaps with a histidine at a key location, is involved in CSF acid-base regulation and that amiloride appears to have no effects on the chemoreception process. DEPC appears to have effects on chemoreception and on CSF acid-base regulation.
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PMID:Effects of amiloride and diethyl pyrocarbonate on CSF HCO-3 and ventilation in hypercapnia. 340 66

The relationship between low-awake chemosensitivity, exogenous respiratory load (obesity) and respiratory/oxygenation patterns during sleep was evaluated in a family with overall low ventilatory responses to hypoxia and hypercapnia. Six family members were of normal weight, in good health and had normal pulmonary function tests. Only one of these subjects had totally normal responses to the chemical control of breathing. A seventh family member had loaded breathing because of severe obesity. His ventilatory and mouth occlusion pressure responses to hypoxia or hypercapnia were severely blunted. After weight loss (200 percent of ideal body weight to 133 percent) the ventilatory responses were improved but still abnormally low. Significant nocturnal respiratory abnormalities and oxygen desaturation were only seen in the overweight member and improved following weight loss (load reduction).
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PMID:The effects of weight and chemosensitivity on respiratory sleep abnormalities: a family study. 377 Oct 93

The technique of high-frequency oscillatory ventilation (HFOV) was successfully used in a preterm infant with severe hyaline membrane disease and in a term neonate presenting with intrauterine pneumonia and associated severe pneumomediastinum. None of the infants could adequately be ventilated by conventional ventilation; both of them deteriorated owing to severe hypoxaemia and hypercapnia. In the preterm infant with HMD a rapid and progressive improvement of oxygenation had been observed immediately after the beginning of HFOV, and he was successfully weaned off the ventilator after 71 hours on HFOV. His recovery was uncomplicated and definitive. In the term neonate presenting with IUP and associated severe PM, an improvement in oxygenation was detected, whereas the retention of paCO2 remained unaltered. On leaving the MAP unchanged but doubling the flow rate, paCO2 and arterial pH also normalised. No sign of PM was seen on the X-ray picture 17.5 hours after the start of HFOV. This patient was weaned off the ventilator after 29 hours on HFOV and his recovery was also uncomplicated. It is believed that recovery of the PM was secondary to the low MAP and to the higher arterial pO2 levels, and that HFOV may also have a direct role in the treatment of preexisting air leaks and perhaps also in their prevention. In our patients HFOV resulted in a definitive recovery, while no improvement had occurred on using conventional ventilation. To determine the exact mechanism of action, the clear cut fields of indications and the possible side effects of HFOV, further investigations are needed.
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PMID:High-frequency oscillatory ventilation (HFOV) in the treatment of neonatal respiratory disturbances: case reports of two infants. 393 21

A patient with Prader-Willi syndrome developed bronchospasm during anesthesia. The patient was a 9-year-old boy and was scheduled for orchiopexy. His psychomotor development was delayed, and at 12 months of age he was diagnosed as Prader-Willi syndrome by chromosomal examination. The patient weighed 17 kg, was 111 cm tall, and had no symptom of upper respiratory infection preoperatively. Preoperative examinations were normal except supraventricular extrasystole in electrocardiogram. Following administration of scopolamine 0.15 mg intramuscularly as preanesthetic medication, anesthesia was induced smoothly by slow induction using N2O-O2-sevoflurane. However, right after endotracheal intubation with vecuronium 2 mg, remarkable stridor was noticed. Despite hyperventilation, the patient exhibited hypercapnia, and the diagnosis of bronchospasm was made. Aminophylline and steroid were administered intravenously and halothane was inhaled instead of sevoflurane. The bronchospasm was improved gradually and surgery was finished. Prader-Willi syndrome is an uncommon disease first reported by Prader in 1956 and characterized by hypotonia, hypomentia, hypogonadism and obesity. In the perioperative management for a patient with Prader-Willi syndrome, special attention must be paid to the abnormalities in the upper and lower respiratory systems.
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PMID:[Bronchospasm during anesthesia in a patient with Prader-Willi syndrome]. 858 65

A 13-year-old boy with juvenile-onset acid alpha glucosidase deficiency was reported. Proximal muscle weakness including respiratory muscles and scoliosis progressed since nine year of age. He developed nocturnal dyspnea and daytime somnolence at age 13. His arterial blood gas analysis showed hypoxemia (PO2 54.1 mmHg) and hypercapnia (PCO2 72.3 mmHg), and spirometry showed significantly decreased vital capacity (% VC 21%). He was treated with nocturnal NIPPV employing a device for delivering bilevel positive airway pressure (Bi-PAP). Nocturnal dyspnea and daytime somnolence rapidly disappeared with nocturnal ventilatory support. Daytime arterial PO2 and PCO2 improved after the therapy, namely 74.8 mmHg and 64.1 mmHg respectively. We conclude that NIPPV is a noninvasive and effective therapy for respiratory failure in patients with chronic progressive neuromuscular disorder including acid alpha glucosidase deficiency.
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PMID:[Chronic respiratory failure in a case with juvenile-onset acid alpha-glucosidase deficiency; successful therapy with nasal intermittent positive pressure ventilation (NIPPV)]. 898 97

ROMK channels are inhibited by intracellular acidification. This pH sensitivity is related to several amino acid residues in the channel proteins such as Lys-61, Thr-51, and His-206 (in ROMK2). Unlike all other amino acids, histidine is titratable at pH 6-7 carrying a positive charge below pH 6. To test the hypothesis that certain histidine residues are engaged in CO(2) and pH sensing of ROMK1, we performed experiments by systematic mutations of all histidine residues in the channel using the site-directed mutagenesis. There are two histidine residues in the N terminus. Mutations of His-23, His-31, or both together did not affect channel sensitivity to CO(2). Six histidine residues are located in the C terminus. His-225, His-274, His-342, and His-354 were critical in CO(2) and pH sensing. Mutation of either of them reduced CO(2) and pH sensitivities by 20-50% and approximately 0.2 pH units, respectively. Simultaneous mutations of all of them eliminated the CO(2) sensitivity and caused this mutant channel to respond to only extremely acidic pH. Similar mutations of His-280 had no effect. The role of His-270 in CO(2) and pH sensing is unclear, because substitutions of this residue with either a neutral, negative, or positive amino acid did not produce any functional channel. These results therefore indicate that histidine residues contribute to the sensitivity of the ROMK1 channel to hypercapnia and intracellular acidosis.
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PMID:Involvement of histidine residues in proton sensing of ROMK1 channel. 1071 95


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