ABSTRACT
Although the administration of alfentanil is routine in neurosurgical anaesthesia, the effects of the drug on cerebrospinal fluid pressure (CSFP) or intracranial pressure (ICP) have been a subject of controversy in the past. Therefore the effects of alfentanil (3 micrograms kg-1) on mean lumbar cerebrospinal fluid pressure (CSFP), heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP) and end-tidal carbon dioxide (ETCO2) in human volunteers without cerebral disease is reported here. The CSFP increased from 9 mmHg (P < 0.05) after intravenous (i.v.) injection of alfentanil, to 12 mmHg whereas MAP, CVP, HR and ETCO2 remained stable throughout the investigative period. The results from this study suggest that alfentanil, even when administered in low doses, leads to a relatively small but statistically significant increase in CSFP in humans with uncompromised intracranial compliance.
Subject(s)
Alfentanil/pharmacology , Analgesics, Opioid/pharmacology , Cerebrospinal Fluid Pressure/drug effects , Adult , Blood Pressure/drug effects , Carbon Dioxide/blood , Cerebrovascular Circulation/drug effects , Female , Heart Rate/drug effects , Humans , Male , Reference ValuesABSTRACT
OBJECTIVE: Determine the influence of urapidil on mean lumbar cerebrospinal fluid pressure (CSFP), mean arterial pressure (MAP), mean central venous pressure (CVP) and heart rate (HR) in awake humans without any evidence of cerebral or cardiovascular disease. DESIGN: Open, single-dose volunteer study. INTERVENTIONS: CSFP was measured via a spinal needle after i.v. injection of a single dose of 0.2 mg kg-1 urapidil in six volunteers (2 female, 4 male). MEASUREMENTS AND RESULTS: After administration of urapidil, CSFP increased from 7 +/- 1 mmHg to 10 +/- 1 mmHg (p < 0.05), MAP decreased from 88 +/- 7 mmHg to 74 +/- 5 mmHg (p < 0.05), CPP decreased from 81 +/- 7 mmHg to 64 +/- 5 mmHg (p < 0.05) and CVP decreased from 0 +/- 1 mmHg to -3 +/- 1 mmHg (p < 0.05). CONCLUSION: Our data suggest that in humans with presumed normal intracranial compliance the administration of urapidil causes a small but statistically significant increase in CSFP due to a parallel decrease in MAP.
Subject(s)
Antihypertensive Agents/pharmacology , Cerebrospinal Fluid Pressure/drug effects , Piperazines/pharmacology , Adult , Blood Pressure/drug effects , Central Venous Pressure/drug effects , Female , Heart Rate/drug effects , Humans , Injections, Intravenous , Male , Middle Aged , Pseudotumor Cerebri/drug therapyABSTRACT
Because hypocapnia is routine during general anaesthesia for intracranial procedures, we have compared, in 13 healthy volunteers, the effect of normocapnia (PE'CO2 5.3 kPa) and hypocapnia (PE'CO2 3.3 kPa) on mean blood flow velocity in the middle cerebral artery (Vmca) during normoventilation and hyperventilation with air and with 50% nitrous oxide in oxygen. After replacement of air with 50% nitrous oxide in oxygen, there was an increase in mean Vmca during normoventilation (air: mean 68.23 (SD 16.98) cm s-1 vs nitrous oxide in oxygen: 90.69 (20.41) cm s-1; P < 0.01), whereas during hyperventilation mean Vmca values were similar regardless of the inhaled gas mixture (air: 43.46 (9.97) cm s-1 vs nitrous oxide in oxygen: 41.69 (8.08) cm s-1. Our data suggest that the nitrous oxide-induced increase in mean Vmca can be blocked by hyperventilation.
Subject(s)
Brain/blood supply , Carbon Dioxide , Hyperventilation/physiopathology , Nitrous Oxide/pharmacology , Adult , Blood Flow Velocity/drug effects , Cerebral Arteries , Female , Humans , Male , Middle AgedABSTRACT
Although sufentanil is frequently used in neuroanesthesia, the effect of the drug on intracranial pressure is still controversial. In our study, we used an invasive measurement technique to study the effects of 0.1 micrograms/kg-1 sufentanil on mean lumbar cerebrospinal fluid pressure (CSFP), mean arterial pressure (MAP), cerebral perfusion pressure (CPP), central venous pressure (CVP), heart rate (HR), and end-tidal dioxide (ETCO2) in five human volunteers. After i.v. injection of sufentanil, mean lumbar CSFP increased from 6 mm Hg to 12 mm Hg (p < 0.05), and mean CPP decreased from 92 mm Hg to 78 mm Hg (p < 0.05), whereas MAP, CVP, HR, and ETCO2 remained stable. The results of this study clearly show that even a low dose of sufentanil transiently increases lumbar CSFP in volunteers with uncompromised intracranial compliance.
Subject(s)
Cerebrospinal Fluid Pressure/drug effects , Sufentanil/pharmacology , Adult , Blood Pressure/drug effects , Carbon Dioxide/metabolism , Central Venous Pressure/drug effects , Cerebrovascular Circulation/drug effects , Female , Heart Rate/drug effects , Humans , Injections, Intravenous , Intracranial Pressure/drug effects , Male , Oxyhemoglobins/analysis , Spinal Puncture , Sufentanil/administration & dosage , Tidal Volume/drug effectsABSTRACT
The effect of a continuous positive airway pressure (CPAP) of 12 cm H2O on mean middle cerebral artery flow velocity (CBFV) was studied in nine human volunteers by means of transcranial Doppler sonography (TCD). During CPAP breathing, CBFV increased (45 +/- 9 vs 59 +/- 11 cm/s; P < 0.001; mean +/- SD), and pulsatility index (PI) decreased (0.87 +/- 0.1 vs 0.74 +/- 0.2; P < 0.05), indicating an increase in cerebral blood flow due to cerebral vasodilation. This phenomenon should be taken into account when CPAP is applied to patients with intracranial disease or when assessing CBFV patterns of patients during CPAP respiration.
