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

Pentamorphone is a novel, potent opiate with rapid onset and short duration of action that has been reported to produce analgesia with limited depression of ventilation. We quantified the effects of pentamorphone (0.08, 0.24, and 0.60 micrograms/kg, IV) on ventilatory responses to hypercapnia and hypoxia in 12 healthy volunteers. Normoxic hypercapnia and isocapnic hypoxia were induced through a rebreathing method. During each test we recorded ventilation (VE), end tidal carbon dioxide tension (PETCO2), and arterial oxygen saturation (SO2) using a pulse oximeter. Using linear regression analysis of the relationships between VE and PCO2 during hypercapnia and VE and SO2 during hypoxia, we determined the slope (slope CO2) and intercept (V55), both at PCO2 55 mm Hg, and the slope (slope O2) and intercept (V80) at SO2 80%. Pentamorphone produced dose-related reductions in the ventilatory responses to both hypercapnia and hypoxia. Maximal depression occurred 15 min after injection of pentamorphone with all doses; the highest dose (0.60 micrograms/kg) produced 48% and 53% reductions in slope CO2 and V55, and 42% and 22% reductions in slope O2 and V80, respectively, relative to parallel saline controls. The respiratory depressant actions of pentamorphone were short-lived, as all parameters returned to baseline levels within 45 min. Testing was continued for 180 min after injection, but no delayed ventilatory effects were detected, and minimal side effects were reported, even at the highest dose. The findings confirm previous reports that pentamorphone has limited ventilatory depressant effects in humans in doses that (in other studies) have been associated with clinically effective analgesia.
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PMID:Depression of ventilatory responses to hypoxia and hypercapnia after pentamorphone. 169 39

The efficacy of acupuncture and transcutaneous stimulation analgesia, supplemented by small doses of fentanyl (mean 1.2 micrograms/kg, SD 1.7) was compared with moderate-dose fentanyl anaesthesia (mean 22.9 micrograms/kg, SD 2.8) in 29 patients who underwent surgery for retroperitoneal lymph node dissection. The present study describes the anaesthetic techniques and comparison of haemodynamics, demand for analgesics after surgery, recovery and blood gases, restoration of urinary and bowel functions, convalescence in terms of self-reliance and the postoperative course in respect of fatigue and morbidity. A more rapid return of consciousness, an absence of hypercapnia and a smaller decrease in pH were observed in patients who received acupuncture and transcutaneous stimulation (p less than 0.05). No clinically relevant disadvantages attributable to the method were demonstrated.
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PMID:Acupuncture and transcutaneous stimulation analgesia in comparison with moderate-dose fentanyl anaesthesia in major surgery. Clinical efficacy and influence on recovery and morbidity. 188 9

The perioperative anaesthetic management of an adult patient with central alveolar hypoventilation syndrome (CAHS), Ondine's Curse, is described for anterior resection of a carcinoma of the bowel. This rare syndrome results in alveolar hypoventilation, hypercarbia, hypoxaemia with secondary polycythaemia, pulmonary artery hypertension, and cor pulmonale. Epidural morphine was used for postoperative analgesia in an attempt to improve postoperative respiratory function. However, postoperative mechanical ventilation was required until recovery of the respiratory drive, which was ablated by anaesthetic drugs, epidural morphine and high inspired oxygen concentrations. The pathophysiology and treatment of this syndrome are reviewed.
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PMID:Anaesthesia for a patient with central alveolar hypoventilation syndrome (Ondine's Curse). 229 95

Hypoventilation produces hypercapnia which can elevate pain thresholds. Hypercapnia is a potent stressor which releases catecholamines and activates the sympathetic nervous system. Some stressors produce analgesia by releasing endogenous opioids. To determine the roles of endogenous opioids and catecholamines in hypercapnic analgesia, we administered CO2 in the inspired gas mixture to conscious rats. CO2 in the range 5-10% elevated tail flick and leg flexion latencies 2- to 3-fold in both intact and spinalised animals. The effects on reflex latencies but not on paCO2 or pHa were blocked by naloxone (2 mg/kg), and were not present in morphine-tolerant animals. The effects were reduced by dexamethasone but were not changed either by adrenalectomy or by systemic guanethidine, propanolol or phentolamine. Hypercapnia delayed the onset of the late phase of behavioural responses to formalin injected into the plantar surface of the hindpaw. We conclude that moderate hypercapnia powerfully depresses flexor withdrawal responses to noxious stimuli, by a mechanism involving release of endogenous opioids but not systemic catecholamines. This effect may account in part for the elevation in pain threshold during hypoventilation.
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PMID:Hypercapnia depresses nociception: endogenous opioids implicated. 235 37

Thoracic epidural fentanyl has been used successfully for postoperative analgesia in patients undergoing thoracic surgery. Prior investigators have suggested that increasing the administered dosage and volume of lumbar epidural fentanyl may increase the spread of analgesia. The feasibility of injecting a high volume (20 mL) of fentanyl into the lumbar epidural space for post-thoracic surgery analgesia was studied in 17 patients undergoing elective thoracotomy or sternotomy. All patients had a lumbar epidural catheter placed before induction of general anesthesia. No narcotic was administered during surgery. Thirty minutes before the conclusion of anesthesia, 200 micrograms of fentanyl in 16 mL of 0.9% saline was administered via the epidural route. In the intensive care unit (ICU), additional fentanyl in the same dosage and volume was injected when the patient complained of pain. Pain was scored on a linear analog scale pre-injection and 30 minutes post-injection. Arterial blood gases were obtained simultaneously. All patients experienced pain relief within 15 minutes of injection. No significant respiratory depression or hypercarbia was noted. Lumbar epidural fentanyl is a safe and practical alternative to thoracic epidural analgesia in the post-thoracic surgical patient.
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PMID:Lumbar epidural fentanyl analgesia after thoracic surgery. 251 38

Bronchoscopy with the fibre bronchoscope under local analgesia influences circulatory and pulmonary function, depending partly on the form of premedication employed, anticholinergic preparations, the local analgesic and the form of application. Physiological and pharmacological knowledge is available on which a rational choice of the method of examination may be based. In order to reduce untoward sequelae of the examination, the following are recommended: avoidance of sedative premedication, which appears to be unnecessary, administration of supplementary oxygen during and for at least two hours after the examination (special care is required in cases of chronic hypercapnia) and employment of anticholinergic preparations, particularly in asthmatic patients. Nevertheless, slight degrees of bronchoconstriction may be anticipated during and after the examination. Examination via an endotracheal tube is warned against in patients with respiratory difficulties. There is much to recommend the choice of lidocaine as the routine analgesic and this is administered in the form of inhalation from an atomizer. On the basis of absorption investigations, the dosage may probably be raised to approximately 7 mg/kg. Patients with cardiac and liver disease have, however, reduced distribution volumes and clearance.
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PMID:[Rational fiberoptic bronchoscopy under local analgesia]. 267 37

A case is reported of acute respiratory failure occurring during upper abdominal surgery in a patient not previously known to have chronic respiratory failure. Preoperatively, this 68 year old patient presented with mild obesity, slight effort dyspnoea and paralysis of the right hemidiaphragm, a sequela of polytrauma she suffered the year before. Respiratory tests were not considered useful with regard to the results of clinical examination. Moreover, she had already several previous general anaesthetics without any problems. A thoracic epidural anaesthesia was performed with a mixture of 150 mg lidocaine, 37.5 mg bupivacaine with adrenaline and 100 micrograms fentanyl, injected in the T8-T9 epidural space via a catheter. Ten minutes after the starting of surgery, the patient became agitated and complained of difficulty in breathing. Blood gas analysis showed hypercapnia, with respiratory acidosis (Pao2: 28.19 kPa; Paco2: 9.2 kPa; pH 7.273). Clinical examination revealed a bilateral Horner syndrome (T1-T4 sympathetic blockade). The patient was intubated and ventilated after adequate sedation. She was extubated 3 h 30 min after the initial epidural injection. Epidural analgesia was maintained during 72 h, with 0.1% bupivacaine, with no recurrence of respiratory failure.
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PMID:[Transient acute respiratory failure and thoracic epidural anesthesia]. 273 73

Hypercapnia in patients with pulmonary disease is believed to result from an interaction between mechanical lung impairment and intrinsic chemical respiratory drive. We tested this hypothesis in this study by examining the ventilatory (delta VE/delta PCO2) and occlusion pressure (delta P100/delta PCO2) responses to CO2 in 12 obese patients with no history of alveolar hypoventilation and correlating these with their ventilatory responses to abdominal surgery. Preoperatively the mean vital capacity (VC) was 78% +/- 6% standard error of the mean predicted, the delta VE/delta PCO2 was 1.56 +/- 0.26 L/min/torr, delta P100/delta PCO2 was 0.25 +/- 0.08 cm H2O/torr, the mean PaCO2 37.9 +/- 1.1 mm Hg, and mean PO2 77.6 +/- 3.7 mm Hg. Postoperatively the VC decreased to 56% +/- 6% of the preoperative value. PCO2 values at 24 hours increased in six patients, were unchanged in three, and decreased in three patients. However, over the entire spectrum of PCO2 change, both indexes of CO2 chemosensitivity correlated strongly with the postoperative change in PCO2 (r = -0.86 for delta VE/delta PCO2 and r = -0.66 for delta P100/delta PCO2). All six patients with a delta VE/delta PCO2 of 1.5 L/min/torr or less manifested postoperative increases in PCO2, while those with greater values did not (p = 0.005). In contrast, neither preoperative nor postoperative VC showed high correlations with postoperative PCO2 (r = -0.56 and -0.43, respectively). Thus ventilatory responses to CO2 predicted postoperative PCO2 at both ends of the spectrum; low responders hypoventilated while high responders hyperventilated. We conclude that in obese subjects, CO2 chemosensitivity plays a permissive role in determining the net ventilatory responses to situations that either mechanically load the respiratory system or modulate ventilation such as postoperative pain or analgesia.
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PMID:Chemical respiratory drive as a determinant of postoperative ventilation in the non-Pickwickian obese patient. 310 48

In 60%-90% of cases head injury is a part of multisystem trauma and of very decisive importance for the post-traumatic prognosis. Hypoxia, hypercarbia, and hypotension increase the primary lesion and cause secondary brain damage. Therefore, emergency measures must be directed to the essentials of sustaining vital functions, i.e. intubation/ventilation/oxygenation and stabilization of the circulatory system. All trauma-specific measures should avoid additional increases in intracranial pressure or should decrease it if already elevated. Moderate hyperventilation not only causes cerebral vasoconstriction with a concomitant decrease in intracranial blood volume and intracranial pressure, but also partly restores the disturbed cerebral autoregulation, and is therefore an important part of the emergency care and anesthetic procedure in patients with severe head injuries. It is supplemented by analgesia and sedation to prevent intracranial pressure increases due to painful external stimuli. Elevation of the head and upper part of the body by 30 degrees causes a decrease in intracranial pressure by decreasing intracranial blood volume due to improved venous return from the brain; however, this measure is to be applied only in stable circulatory conditions. The head should be put in mid-position avoiding sideways rotation, flexion, and hyperextension. Osmotically active agents are only indicated in emergency situations when there are signs of clinical deterioration. High-dose barbiturate therapy is reserved as a "last resort", under intensive care conditions, for controlling an otherwise intractable intracranial pressure rise. Calcium antagonists have no indication in this context. Anesthesia in patients with severe head injury must involve only those techniques that do not further increase an already elevated intracranial pressure. As inhalational anesthetics, including nitrous oxide, elevate the intracranial pressure to varying extents due to cerebral vasodilation with a concomitant rise in intracranial blood volume, these substances have to be avoided whenever raised intracranial pressure cannot be excluded. Narcotics, benzodiazepines, small dosages of barbiturates, and long-lasting muscle relaxants can be regarded as useful.
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PMID:[Pathophysiologic principles, emergency medical aspects and anesthesiologic measures in severe brain trauma]. 331 Jul 24

To assess the effect of thoracic epidural analgesia (TEA) on postoperative respiratory function and pulmonary complications, a prospective randomized trial was conducted in patients undergoing cholecystectomy. One hundred patients were allocated to TEA (n = 30), TEA + general anesthesia (TEA + GA) (n = 30), or general anaesthesia (GA) (n = 40) groups. Respiratory function was analysed by measuring forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), functional residual capacity (FRC), total lung capacity (TLC), peak expiratory flow (PEF) in the supine and sitting postures, and arterial blood gases. Postoperative pulmonary complications were carefully documented. TEA significantly prevented the postoperative deterioration of respiratory function as compared with general anaesthesia. FVC, FEV1 and PEF decreased by 20% in patients receiving TEA, in contrast to 55% in patients after GA on the day of operation. This improvement continued until the 2nd day after operation, when FVC, FEV1 and PEF and their recovery rates were equal in all groups. In the sitting posture the preoperative FVC, FEV1 and PEF were about 10% greater than in the supine position. After operation, this difference was further increased. The preoperative difference of 27% in FRC between the sitting and supine postures was maintained after operation. PaO2 decreased by 0.8 kPa after TEA, by 1.5 kPa after TEA + GA with the lowest value on the 2nd postoperative day and by 1.5 kPa after GA, with the lowest value immediately after operation. Simultaneous hypercarbia indicated hypoventilation, which may have contributed to impaired respiratory function on the following days.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effect of thoracic epidural analgesia on respiratory function after cholecystectomy. 368 60


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