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

A 21-year old women with rhizomelic muscular deficit and signs of hypercapnia developed acute respiratory failure. Laboratory tests revealed high creatine kinase activity, and electromyograms showed myogenic patterns with a few myotonic discharges. Biopsy of the quadriceps muscle elicited major vacuolar myopathy with glycogen overload. Acid maltase activity was undetectable in muscular tissue. After 7 months on high-protein diet (1540 calories, 37% proteins) there was no clinical or biochemical improvement. The other published cases of acid maltase deficiency treated with high-protein diet are discussed.
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PMID:[Myopathy in adults caused by acid maltase deficiency. A trial of treatment with high protein diet]. 141 Aug 90

Although central nervous system (CNS) involvement, such as intellectual impairment simulating dementia, in myotonic dystrophy (MyD) has been well documented, the cause of this condition remains unclear. In has been reported that the progressive cases of MyD are often accompanied with respiratory disturbance and sleep apnea syndrome (SAS). We studied the relation between CNS involvement and respiratory disorders in 15 MyD patients. They consisted of 10 males and 5 females with ages ranging from 21 to 58 years (average 46 +/- 8.4 years old). Arterial blood gas (ABG) analysis, respiratory function test, and monitoring of arterial oxygen saturation (SaO2) during sleep were carried out. In some cases abnormal respiration during sleep was analyzed with polysomnography. For an assessment of CNS involvement the following examinations were performed; intelligence quotient (WAIS-IQ); electroencephalography (EEG); brain computed tomography (CT); and cerebrospinal fluid (CSF) levels of neuron-specific enolase (NSE), S-100b and creatine kinase BB isoenzyme (CK-BB) which were estimated by using enzyme immunoassay. ABG analysis demonstrated the presence of hypercapnia (PaCO2 > 45 torr) during wakefulness in MyD patients. During sleep 14 of the 15 patients showed frequent desaturation phenomenon (SaO2 < 90%), indicating the episodic hypoxemia. Polysomnographic study revealed the occurrence of SAS of both obstructive and central types in all the cases examined. IQ test disclosed intellectual impairment in 80% of the 15 patients, and EEG showed slowing of basic rhythm in the majority of the cases. On brain CT both enlarged ventricles and dilated sulci were commonly observed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Central nervous system disorders in patients with myotonic dystrophy--in relation to respiratory dysfunction]. 142 35

NMR in vivo spectroscopy is one of the few methods available for non-invasive investigations of cerebral metabolism in animals and humans. 31P and 1H spectroscopy are particularly suitable for monitoring the cerebral energy metabolism by determining the cerebral levels of ATP, ADP, phosphocreatine (PCr), inorganic phosphate (Pi), lactate and intracellular pH (pHi). These techniques also seem to be suitable for studying the effects of anesthetics by directly comparing the anesthetized and unanesthetized states in the same subject. The effects of halothane and isoflurane on the changes elicited in the cerebral energy metabolism by experimental hypercapnia were investigated by in vivo NMR spectroscopy. Halothane was found to aggravate the decrease in PCr attributed to the shift in creatine kinase equilibrium induced by the cerebral acidosis associated to hypercapnia, while the level of cerebral ADP was decreased to a lesser extent than in unanesthetized animals. In contrast isoflurane did not modify the changes in cerebral energy metabolism elicited by hypercapnia except that the decrease in PCr was significantly slowed, suggesting a lower creatine kinase activity. These data indicate that isoflurane and halothane act by two different mechanisms to produce a decrease in oxygen consumption. Halothane could interfere with oxidative metabolism by disturbing ATP metabolism, while isoflurane could decrease oxygen consumption by a general sedative action, slowing both cerebral functional activity and cerebral energy homeostasis.
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PMID:[Value of in vivo NMR spectroscopy in the study of cerebral metabolism under inhalation anesthesia]. 184 37

This retrospective study was undertaken to examine the management and outcome of children who developed isolated masseter muscle spasm (MMS) after the administration of intravenous succinylcholine during anesthetic induction. The inhalation anesthetics used for induction were continued in all of these cases. The medical records of 68 patients (male/female ratio, 1.7:1), identified from approximately 42,000 anesthetics given during the period 1980-1989, were reviewed. Fifty-seven children (2.3-12 yr old) were diagnosed as having isolated MMS, i.e., MMS without spasm of other muscles; 11 experienced generalized rigidity in combination with MMS. Anesthetic and postoperative management of these two groups differed. The overall incidence of MMS was 0.3% of inhalation anesthetics during which succinylcholine was given. Intraoperative arrhythmias occurred in 33% of the patients who developed isolated MMS and more frequently in older children. Most children experienced some degree of hypercarbia and/or metabolic acidosis, but the significance of these abnormalities in the spontaneously ventilating, fasting child is unknown. Serum creatine kinase levels when measured 18-24 h postoperatively were elevated in all but one child (n = 45). There was no long-term morbidity and no mortality. We conclude that failure of the masseter muscles to relax after succinylcholine is not uncommon in children. Based on our experience, and accepting that MMS may be part of the clinical spectrum of malignant hyperthermia, we believe that anesthesia can be continued safely in cases of isolated MMS when careful monitoring accompanies diagnostic evaluation. This differs from the current practice of discontinuing the anesthetic or switching to a nontriggering anesthetic technique.
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PMID:Masseter muscle spasm in children: implications of continuing the triggering anesthetic. 186 39

The intracellular energetic environment of rat hippocampal slices was manipulated by bolstering ATP levels following the addition of adenosine to the incubation medium, or by manipulating intracellular pH. Addition of 8 mM adenosine to the incubation medium increased total tissue adenylate and ATP content, but did not prolong electrical function during anoxia. Further, it resulted in long-lasting alterations in normoxic evoked responses. Intracellular pH (pHi) was changed by manipulating the bicarbonate/CO2 ratio of the incubation medium, or by adding amiloride, a hydrogen/sodium antiport blocker. Estimates of intracellular pH using the creatine kinase equilibrium agree with those obtained by Neutral red scanning spectrophotometry in control conditions. However, only Neutral red indicated an acidification with amiloride treatment, while the creatine kinase equilibrium was preferentially affected by hypercapnia, suggesting the presence of at least two pH compartments in hippocampal brain slices. These manipulations cannot be carried out easily in vivo, and provide a means of determining the importance of metabolic changes on neural function during anoxia.
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PMID:Manipulating the intracellular environment of hippocampal slices: pH and high-energy phosphates. 272 18

1. The effects of hypercapnia and hypocapnia on brain intracellular pH (pHi) and metabolism were investigated in new-born lambs under barbiturate anaesthesia. 2. 31P nuclear magnetic resonance (n.m.r.) spectroscopy was used to determine brain pHi and the relative concentrations of compounds containing mobile phosphorus nuclei including phosphocreatine (PCr), nucleoside triphosphates (NTP) and inorganic phosphate (Pi). Simultaneous measurements were made of the molar ratio of glucose to oxygen uptake by the brain. 3. During normocapnia (arterial partial pressure of CO2 Pa, CO2, 39 +/- 1 mmHg mean +/- S.E. of mean, n = 9) brain pHi was 7.13 +/- 0.02. Hypercapnia (Pa, CO2, 98 +/- 3 mmHg) was associated with a fall in brain pHi to 6.94 +/- 0.03 (n = 19, P less than 0.001), whereas no significant change in brain pHi occurred during hypocapnia (Pa, CO2, 16 +/- 1 mmHg; brain pHi 7.15 +/- 0.01). 4. During hypercapnia there was an increase in the ratio of Pi to NTP from 1.09 +/- 0.08 to 1.47 +/- 0.06 (P less than 0.001) and a decrease in the ratio PCr/Pi from 1.60 +/- 0.08 to 0.93 +/- 0.04 (P less than 0.001). There was a linear correlation between Pi/NTP and brain pHi. 5. Alterations in arterial PCO2 had no significant effect on the molar ratio of glucose to oxygen uptake by the brain, which remained close to unity. 6. The change in brain pHi observed during hypercapnia can be accounted for by the known physico-chemical buffering capacity of brain tissue. Homoeostasis of brain pHi during hypocapnia provides further evidence that additional regulatory mechanisms operate in these circumstances. 7. The observed changes in PCr and Pi can be accounted for in part by the [H+] dependence of the creatine kinase reaction.
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PMID:Brain intracellular pH and metabolism during hypercapnia and hypocapnia in the new-born lamb. 311 75

The relationships between pHi (intracellular pH) and phosphate compounds were evaluated by nuclear magnetic resonance (NMR) in normo-, hypo-, and hypercapnia, obtained by changing fractional inspired concentration of CO2 in dogs anesthetized with 0.75% isoflurane and 66% N2O. Phosphocreatine (PCr) fell by 2.02 mM and Pi (inorganic phosphate) rose by 1.92 mM due to pHi shift from 7.10 to 6.83 during hypercapnia. The stoichiometric coefficient was 1.05 (r2 = 0.78) on log PCr/Cr against pHi, showing minimum change of ADP/ATP and equilibrium of creatine kinase in the pH range of 6.7 to 7.25. [ADP] varied from 21.6 +/- 4.1 microM in control (pHi = 7.10) to 26.8 +/- 6.3 microM in hypercapnia (pHi = 6.83) and 24.0 +/- 6.8 microM in hypocapnia (pHi = 7.17). ATP/ADP X Pi decreased from 66.4 +/- 17.1 mM-1 during normocapnia to 25.8 +/- 6.3 mM-1 in hypercapnia. The ADP values are near the in vitro Km; thus ADP is the main controller. The velocity of oxidative metabolism (V) in relation to its maximum (Vmax) as calculated by a steady-state Michaelis-Menten formulation is approximately 50% in normocapnia. In acidosis (pH 6.7) and alkalosis (pH 7.25), V/Vmax is 10% higher than the normocapnic brain. This increase of V/Vmax is required to maintain cellular homeostasis of energy metabolism in the face of either inhibition at extremes of pH or higher ATPase activity.
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PMID:Relationship between intracellular pH and energy metabolism in dog brain as measured by 31P-NMR. 359 78

This study identifies a subgroup of critically ill patients most likely to develop at least creatine kinase-myocardial isoenzyme (CK-MB) evidence of acute myocardial injury. This group is composed of patients with shock syndromes associated with some combination of anemia, hypoxemia, hypercarbia, acidemia, lactic acidosis, and hypotension. The mechanism of this secondary myocardial injury in shock is not clear but may be multifactorial. Certainly subgroups of patients admitted with critical illnesses may have CK-MB abnormalities usually associated with acute myocardial injury.
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PMID:Secondary myocardial injuries. 650 98

A 6-year old female child received succinylcholine (1 mg.kg-1) and isoflurane (concentrations of 1.5-2 percent) and developed at the end of surgery a hypermetabolic syndrome suggestive of malignant hyperthermia (MH) with masseter muscle spasm, muscle rigidity, tachypnea, systolic hypertension (140 mm Hg), tachycardia (205 beats.min-1), hypercarbia (end expiratory CO2 71 mmHg), and an increase in body temperature (39.2 degrees C). The child responded well to therapy which included cooling, hyperventilation with pure oxygen and dantrolene administration. However, blood creatine kinase and myoglobin elevations were moderate (respectively 375 IU.L-1 and 114 micrograms.L-1) and an in vitro halothane and caffeine contracture test was negative. Differential diagnostic proposals are discussed and compared to the clinical incident.
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PMID:Malignant hyperthermia suggestive hypermetabolic syndrome at emergence from anesthesia. 871 51

We report a 55-year-old woman with typical clinical, biochemical and radiological features of Cushing's disease, who developed a severe respiratory insufficiency as the main symptom. She also complained of proximal muscle weakness over the last year and progressive dyspnea over the last four months. Bronchospasm, respiratory infection or cardiologic dysfunction were excluded. Arterial blood gas analysis showed severe respiratory insufficiency with hypoxemia and hypercapnia, respiratory acidosis and a normal alveolar-arterial oxygen gradient. Spirometry and plethysmography showed a restrictive ventilatory failure and maximum inspiratory and expiratory pressures were reduced. These findings were strongly suggestive of neuromuscular disease. Serum creatine kinase, aldolase, sodium, potassium and thyroid function tests were normal. An electromyogram and a muscle biopsy confirmed myopathic disease. Ketoconazole therapy improved her symptoms and respiratory function tests. In conclusion although proximal myopathy is a frequent presenting symptom of Cushing's syndrome, involvement of respiratory muscles with severe restrictive ventilatory dysfunction has not been previously reported as the main initial feature of Cushing's disease. Medical treatment of hypercortisolism improves muscle strength and resolves the respiratory insufficiency.
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PMID:Severe respiratory failure secondary to Cushing's myopathy. 1168 45


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