thiopental and Hyperventilation

Transcranial Doppler and, if possible, measurement of intracranial pressure (ICP) allow preoperative diagnosis of acute intracranial hypertension (ICH) after brain trauma. The main goal of the anaesthesiologist is to prevent the occurrence of secondary brain injuries and to avoid cerebral ischaemia. Treatment of high ICP is mainly achieved with osmotherapy. High-dose mannitol administration (1.4 to 2 g/kg given in bolus doses) may be considered a better option than conventional doses, especially before emergency evacuation of a cerebral mass lesion. Hypertonic saline seems as effective as mannitol without rebound effect and without diuresis increase. Haemostasis should be normalized before neurosurgery and invasive blood pressure monitoring is mandatory. For anaesthesia induction, thiopental or etomidate may be used. In case of ICH, halogenated and nitrous oxide should be avoided. Until the dura is open, mean arterial pressure should be maintained around 90 mmHg (or cerebral perfusion pressure around 70 mmHg). If a long-lasting (several hours) extracranial surgery is necessary, ICP should be monitored and treatment of ICH should have been instituted before.

Topics: Acute Disease; Anesthesia, General; Blood Pressure; Brain Injuries; Brain Ischemia; Case Management; Combined Modality Therapy; Comorbidity; Contraindications; Diuretics, Osmotic; Etomidate; Humans; Hyperventilation; Intracranial Hypertension; Jugular Veins; Mannitol; Monitoring, Intraoperative; Monitoring, Physiologic; Nitrous Oxide; Oxygen; Preoperative Care; Saline Solution, Hypertonic; Thiopental; Tomography, X-Ray Computed; Ultrasonography, Doppler, Transcranial; Wounds and Injuries

Topics: Anesthesia; Anesthesia, Inhalation; Anesthesia, Intravenous; Child; Consciousness; Eating; Gastric Juice; Gastroesophageal Reflux; Gastrostomy; Humans; Hydrogen-Ion Concentration; Hyperventilation; Infant; Infant, Newborn; Inhalation; Intubation, Intratracheal; Methods; Posture; Preanesthetic Medication; Preoperative Care; Stomach; Succinylcholine; Thiopental; Wakefulness

Disturbed autoregulation and CO2 reactivity have been reported in patients with brain tumors. Therefore, we decided to monitor the cerebrovascular effects of anesthetic drugs and hyperventilation. Transcranial Doppler sonography (TCD) can measure noninvasively alterations of flow velocities (v) and cross-sectional vessel area (VA) in large brain arteries. Twenty-eight patients with large malignant brain tumors in the territory of the middle cerebral artery (MCA) randomly received propofol or thiopental for induction and maintenance of anesthesia. Mean arterial pressure (MAP), heart rate (HR), and TCD parameters (vMCA and VA of the tumor or nontumor side) were determined at six data points (DP). The first measurements (MAP, HR, and TCD of the nontumor side) were performed before (DP I) and 60 s after (DP II) induction of anesthesia with either 2 mg/kg propofol or 4 mg/kg thiopental. After intubation and normoventilation (50% O2 in air), 0.05-0.1 mg/kg midazolam and an alfentanil infusion (100 micrograms/kg x h) were initiated. Then MAP, HR, vMCA, and VA of the tumor side were analyzed before (DP III) and 60 s after (DP IV) either propofol (1 mg/kg) or thiopental (2 mg/kg) were given. Finally, the effects of hyperventilation on HR, MAP, vMCA, and VA (tumor side) were determined (DP V and VI). Mean +/- SD, thiopental or propofol reactivity (non-tumor and tumor side) and CO2 reactivity (tumor side) were calculated; statistical comparison between DP I and II, III and IV, and V and VI was performed by paired t tests (p < 0.05). Unpaired t tests were used to evaluate differences between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Anesthesia, General; Astrocytoma; Brain Neoplasms; Female; Glioma; Hemodynamics; Humans; Hyperventilation; Male; Middle Aged; Monitoring, Intraoperative; Propofol; Thiopental; Ultrasonography

Topics: Adult; Anesthesia, General; Clinical Trials as Topic; Drug Evaluation; Humans; Hyperventilation; Intraoperative Complications; Isoflurane; Male; Naloxone; Premedication; Spinal Cord Injuries; Thiopental

Topics: Androstanes; Anesthesia; Atropine; Clinical Trials as Topic; Gallamine Triethiodide; Halothane; Humans; Hyperventilation; Injections, Intravenous; Neostigmine; Neuromuscular Nondepolarizing Agents; Nitrous Oxide; Oxygen; Piperidines; Thiopental

Topics: Abortion, Therapeutic; Adult; Anesthesia, Inhalation; Anesthesia, Intravenous; Anesthesia, Obstetrical; Ethers; Female; Gestational Age; Halothane; Humans; Hyperventilation; Meperidine; Nitrous Oxide; Pregnancy; Pulmonary Alveoli; Respiration; Thiopental; Uterine Hemorrhage

Fulminant hepatic failure (FHF) is often complicated by high intracranial pressure (ICP) and fatal brain damage. In this study, we determined if a rise in [glutamate]ec and [lactate]ec preceded surges of high ICP in patients with FHF (median age, 42; range, 20-55 years; 7 women; 3 men) by inserting a microdialysis catheter into the brain-cortex together with an ICP catheter. The microdialysis catheter was perfused with artificial cerebrospinal-fluid at a rate of 0.3 microL/min. Dialysate was collected approximately every 30 minutes or when ICP increased. A total of 352 microdialysis samples were collected during a median of 3 days and allowed for approximately 1,760 bedside analyses of the collected dialysate. In 5 patients that later developed surges of high ICP, the initial values of [glutamate]ec and [lactate]ec were 2 to 5 times higher compared with patients with normal ICP. [Glutamate]ec then tended to vanish with time in both groups of patients. An increase in [glutamate]ec did not precede high ICP in any of the cases. In contrast, [lactate]ec was high throughout the study in the high ICP group and increased further before surges of high ICP. We conclude that in patients with FHF, cerebral [glutamate]ec and [lactate]ec are elevated. However, the elevated [glutamate]ec is not correlated to high ICP. In contrast, elevations in [lactate]ec preceded surges of high ICP. In conclusion, accelerated glycolysis with lactate accumulation is implicated in vasodilatation and high ICP in patients with FHF. The data suggest that bedside cerebral microdialysis is a valuable tool in monitoring patients with FHF and severe hyperammonemia.

Topics: Adult; Female; Glutamic Acid; Humans; Hyperventilation; Hypnotics and Sedatives; Hypothermia, Induced; Intracranial Hypertension; Lactic Acid; Liver Failure; Longitudinal Studies; Male; Microdialysis; Middle Aged; Thiopental

Sustained hyperventilation has a time-limited effect on cerebrovascular dynamics. We investigated whether this effect was similar among brain regions by measuring regional cerebral blood volume (CBV) with steady-state susceptibility contrast magnetic resonance imaging during 3 h of hyperventilation. Regional CBV was determined in nine thiopental-anesthetized, mechanically-ventilated rats every 30 min in the dorsoparietal neocortex, the corpus striatum, and the cerebellum. The corpus striatum was the only brain region showing a stable reduction in CBV during the hypocapnic episode (PaCO(2), 24 +/- 3 mm Hg). In contrast, neocortex and, to a lesser extent, cerebellum exhibited a progressive return toward normal values despite continued hypocapnia. No evidence of a rebound in CBV was found on return to normal ventilation in the three brain regions. We conclude that sustained hyperventilation can lead to an uneven change in the reduction of CBV, possibly because of differences of brain vessels in their sensitivity to extracellular pH. Our results in neocortex confirm the transient effect of sustained hyperventilation on cerebral hemodynamics.. Sustained hyperventilation has a transient effect in decreasing cerebral blood volume (CBV). Using susceptibility contrast magnetic resonance imaging in thiopental-anesthetized rats, we found differences between brain regions in their transient CBV response to sustained hyperventilation.

Topics: Anesthesia; Anesthetics, Intravenous; Animals; Blood Volume; Cerebrovascular Circulation; Contrast Media; Female; Hydrogen-Ion Concentration; Hyperventilation; Rats; Rats, Sprague-Dawley; Thiopental

The effect of indomethacin, a cyclooxygenase inhibitor, was studied in the treatment of 10 patients with head injury and one patient with spontaneous subarachnoid hemorrhage, each of whom presented with high intracranial pressure (ICP) (34.4 +/- 13.1 mm Hg) and cerebral perfusion pressure (CPP) impairment (67.0 +/- 15.4 mm Hg), which did not improve with standard therapy using mannitol, hyperventilation, and barbiturates. The patient had Glasgow Coma Scale scores of 8 or less. Recordings were made of the patients' ICP and mean arterial blood pressure from the nurse's end-hour recording at the bedside, as well as of their CPP, rectal temperature, and standard therapy regimens. The authors assessed the effects of an indomethacin bolus (50 mg in 20 minutes) on ICP and CPP; an indomethacin infusion (21.5 +/- 11 mg/hour over 30 +/- 9 hours) on ICP, CPP, rectal temperature, and standard therapy regimens (matching the values before and during infusion in a similar time interval); and discontinuation of indomethacin treatment on ICP, CPP, and rectal temperature. The indomethacin bolus was very effective in lowering ICP (p < 0.0005) and improving CPP (p < 0.006). The indomethacin infusion decreased ICP (p < 0.02), but did not improve CPP and rectal temperature. The effects of standard therapy regimens before and during indomethacin infusion showed no significant changes, except in three patients in whom mannitol reestablished its action on ICP and CPP. Sudden discontinuation of indomethacin treatment was followed by significant ICP rebound. The authors suggest that indomethacin may be considered one of the frontline agents for raised ICP and CPP impairment.

Topics: Adolescent; Adult; Blood Pressure; Body Temperature; Brain Injuries; Carbon Dioxide; Cerebrovascular Circulation; Child; Cyclooxygenase Inhibitors; Female; Glasgow Coma Scale; Humans; Hyperventilation; Indomethacin; Infusions, Intravenous; Injections, Intravenous; Intracranial Pressure; Male; Mannitol; Pseudotumor Cerebri; Rectum; Subarachnoid Hemorrhage; Thiopental

Topics: Adult; Aged; Anesthesia; Arteries; Carbon Dioxide; Cerebral Cortex; Female; Humans; Hyperventilation; Male; Middle Aged; Monitoring, Intraoperative; Oxygen Consumption; Oxyhemoglobins; Propofol; Thiopental

Mean hemispheric cerebral blood flow (CBF) and intracranial pressure (ICP) were measured in 19 severely head-injured patients treated with barbiturate coma. The CBF was calculated from the clearance of tracer substance monitored by extracranial scintillation detectors after intravenous administration of xenon-133. In 11 of the patients cerebral arteriovenous oxygen differences were measured simultaneously. In all patients the effects of pronounced hyperventilation were recorded prior to initiation of barbiturate treatment. A normal CBF response to hyperventilation (delta CBF/delta PaCO2 greater than or equal to 1) was obtained in eight patients. In these patients induction of barbiturate coma was accompanied by physiological decreases in CBF and in the calculated cerebral metabolic rate of oxygen (CMRO2); they also exhibited a rapid and lasting decrease in ICP. A decreased or an abolished CO2 reactivity was recorded (delta CBF/delta PaCO2 less than 1) in 11 patients. In 10 of these 11 patients the physiological decreases in CBF and CMRO2 were not obtained during barbiturate treatment and the decrease in ICP was transitory. This study demonstrates a correlation between cerebral vasoreactivity, physiological effects of barbiturate therapy, and clinical outcome.

Topics: Adolescent; Adult; Brain; Brain Injuries; Carbon Dioxide; Cerebrovascular Circulation; Child; Coma; Female; Humans; Hyperventilation; Male; Middle Aged; Oxygen; Oxygen Consumption; Thiopental; Vascular Resistance

In 13 dogs the response of the cerebral circulation to changes in PaCO2 ranging from 20 to 60 torr was studied before and after administration of high doses of sodium thiopental. Infusion of sufficient barbiturate to produce 30- to 60-second burst suppression in the electroencephalogram was associated with a profound degree of cerebral vasoconstriction, equivalent to that produced by hypocapnia with PaCO2 = 20 torr. Furthermore, once sodium thiopental was administered, no significant difference in cerebral blood flow (CBF) or vascular resistance (CVR) was noted between PaCO2 of 30 and 20 torr. However, changes of approximately 15% in CBF and 30% in CVR were noted between PaCO2 at 40 and 20 torr. These data suggest that hyperventilation of PaCO2 of less than 30 torr may not effectively increase the degree of cerebral vasoconstriction in these circumstances.

Topics: Animals; Blood Pressure; Brain; Carbon Dioxide; Cerebral Arteries; Dogs; Hyperventilation; Thiopental; Vasoconstriction

Conray (meglumine iothalamate), the contrast media frequently used in shuntograms for diagnosing malfunctioning ventriculo-peritoneal shunts, will occasionally cause severe muscular spasms and seizures. In this article, the authors describe anesthetic and critical care management of a case with this complication.

Topics: Anesthesia, Inhalation; Anesthesia, Intravenous; Cerebrospinal Fluid Shunts; Child; Diazepam; Female; Humans; Hyperventilation; Iothalamate Meglumine; Muscle Spasticity; Pancuronium; Positive-Pressure Respiration; Seizures; Thiopental

The effects of hyperventilation, osmotic and diuretic agents (urea, frusemide), thiopentone and succinylcholine chloride on the intracranial pressure were studied in neurosurgical patients with brain tumours. We have shown that hyperventilation together with osmotic and diuretic agents is very useful for reducing increased intracranial pressure.

Topics: Brain Neoplasms; Humans; Hyperventilation; Intracranial Pressure; Succinylcholine; Thiopental; Urea

Topics: Acid-Base Equilibrium; Adolescent; Adult; Aged; Blood Pressure; Calcium Chloride; Cardiac Output; Child; Droperidol; Electroencephalography; Fentanyl; Halothane; Heart Rate; Humans; Hyperventilation; Intubation, Intratracheal; Middle Aged; Neuroleptanalgesia; Nitrous Oxide; Oxygen; Propanidid; Respiration; Thiopental

Topics: Animals; Brain; Carbon Dioxide; Cardiac Output; Cerebrospinal Fluid; Cerebrovascular Circulation; Dogs; Heart; Hemoglobins; Hyperventilation; Hypothermia, Induced; Lung; Lung Volume Measurements; Nitrogen; Oxygen Consumption; Thiopental

Topics: Adult; Anesthesia, General; Anesthetics; Auditory Perception; Carbon Dioxide; Cognition; Depression, Chemical; Dreams; Humans; Hyperventilation; Male; Memory, Short-Term; Motor Skills; Nitrous Oxide; Perception; Reaction Time; Respiration, Artificial; Task Performance and Analysis; Thiopental; Time Factors; Tubocurarine; Visual Perception

Topics: Adult; Blood Flow Velocity; Blood Pressure; Carbon Dioxide; Cardiovascular System; Curare; Cyclopropanes; Halothane; Heart Rate; Humans; Hypercapnia; Hyperventilation; Narcotics; Respiration; Respiratory Function Tests; Tachycardia; Thiopental; Vascular Resistance

Topics: Acidosis; Adenosine Triphosphate; Anesthesia, General; Animals; Cyanosis; Fever; Halothane; Hyperventilation; Muscles; Oxygen; Prognosis; Sodium; Swine; Tachycardia; Thiopental

Topics: Animals; Arrhythmias, Cardiac; Dogs; Drug Synergism; Epinephrine; Halothane; Heart; Hypercapnia; Hyperventilation; Rabbits; Thiopental

Topics: Analysis of Variance; Anesthesia, General; Apnea; Arrhythmias, Cardiac; Blood Specimen Collection; Bronchoscopy; Carbon Dioxide; Catheterization; Cyanosis; Female; Humans; Hypercapnia; Hyperventilation; Lidocaine; Male; Middle Aged; Oxygen; Oxygen Consumption; Positive-Pressure Respiration; Succinylcholine; Thiopental; Vocal Cords

Topics: Anesthesia, General; Arrhythmias, Cardiac; Atropine; Cardiac Surgical Procedures; Humans; Hyperventilation; Methoxyflurane; Nitrous Oxide; Oxygen; Postoperative Complications; Preanesthetic Medication; Scopolamine; Tachycardia; Thiopental; Thoracic Arteries; Tubocurarine; Ventricular Fibrillation

Topics: Adult; Anesthesia, Endotracheal; Carbon Dioxide; Ethyl Ethers; Halothane; Humans; Hyperventilation; Methoxyflurane; Nitrous Oxide; Oxygen; Partial Pressure; Pulmonary Circulation; Succinylcholine; Thiopental

Topics: Adolescent; Adult; Aged; Anesthetics; Apnea; Blood Pressure; Child; Female; Halothane; Humans; Hyperventilation; Hypotension; Male; Middle Aged; Postoperative Complications; Pulse; Tachycardia; Thiopental

Topics: Anesthesia; Anesthesia, Intravenous; Anesthetics; Anesthetics, Intravenous; Apnea; Barbiturates; Hyperventilation; Methohexital; Pharmacology; Preanesthetic Medication; Spirometry; Succinylcholine; Thiopental; Toxicology

Topics: Anesthesia; Anesthesia, Endotracheal; Brain; Brain Diseases; Brain Neoplasms; Humans; Hydroxyzine; Hyperventilation; Intracranial Pressure; Neurosurgery; Osmosis; Respiration, Artificial; Succinylcholine; Thiopental

Topics: Animals; Asphyxia; Carbon Dioxide; Collapse Therapy; Epinephrine; Ganglia; Ganglia, Spinal; Hyperventilation; Hypoxia; Medulla Oblongata; Nitrogen; Pharmacology; Physiology; Pons; Rabbits; Research; Respiration; Respiration, Artificial; Sympathetic Nervous System; Thiopental; Vagotomy