Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Jan 1978
Flow requirements in the Hafnia modifications of the Mapleson circuits during spontaneous respiration.
The Mapleson A, B, C and D circuits can be changed into non-polluting circuits by employing continuous gas evacuation directly from the circuit, via an ejector flowmeter (Jørgensen 1974); Mapleson A and C circuits with this modification have been described previously as the Hafnia A and C circuits (Christensen 1976, Thomsen & Jørgensen 1976). If evacuation from a closed reservoir is employed, total removal of the expired and surplus gases from the operating theatre is obtained (Jørgensen & Thomsen 1976). There will be resistance to expiration in all the circuits with a relief valve for the discharge of surplus gas. ⋯ As in any other circuit, the relief valve remains open except during controlled ventilation. A dumping valve may also be included as a safeguard against low pressures (Jørgensen & Thomsen 1976). The flow requirements of the Hafnia B and D circuits and the corresponding Mapleson circuits have been studied in conscious, spontaneously breathing subjects, and the results are discussed in relation to the flow requirements of other semi-closed system.
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Acta Anaesthesiol Scand · Jan 1978
Effects on muscarinic receptors of various agents in reversal of neuro-muscular blockade: a study evaluating atropine, glycopyrron, neostigmine and pyridostigmine.
The effects were studied of various drug combinations, recommended for use in reversal of neuromuscular blockade, on heart rate and salivary secretions in 80 healthy patients anaesthetized with nitrous oxide-oxygen-halothane and relaxed with d-tubocurarine. The drug combinations were mixtures of atropine 1 mg--neostigmine 2.5 mg, atropine 1 mg--pyridostigmine 15 mg, glycopyrron 0.5 mg--neostigmine 2.5 mg, and glycopyrron 0.5 mg--pyridostigmine 15 mg, respectively. It was found that administration of the atropine-containing mixtures induced more pronounced initial increases and delayed decreases in heart rate than the mixtures containing glycopyrron. ⋯ No such difference was found between the atropine and glycopyrron groups. Glycopyrron caused a more intense dryness of the mouth than atropine. A differential attitude towards the use of drugs for reversal of neuromuscular blockade, based on the cardiovascular state of the particular patient, might be recommendable.
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Acta Anaesthesiol Scand · Jan 1978
Longitudinal spread of intraneurally injected local anesthetics. An experimental study of the initial neural distribution following intraneural injections.
Unexpected spinal anesthesia, occurring after peripheral nerve blocks close to the spine, may be caused by a centripetal spread of the local anesthetic along the injected nerve to the spinal cord. In order to analyze the pathway of such a spread, a radioactive local anesthetic mixed with a fluorescent dye was injected into difrerent compartments of the rabbit sciatic nerve, and the early distribution of these tracers was studied by scintillation counting and fluorescence microscopy. Epineurial (extrafascicular) injections were of low injection pressure (25-60 mmHg) (3.3-7.9 kPa) and limited spread, while endoneurial (intrafascicular) injections reached higher pressures (300-750 mmHg) (39.9-99.7 kPa) and caused a rapid spread over long distances within the fascicle. ⋯ However, 20% of endoneurial injections reached the spinal cord, where the injectate primarily spread in the thin subpial space. Our experimental findings suggest that intraneural injections of local anesthetics are responsible for the reported cases of unexpected spinal anesthesia due to inadvertent intrafascicular spread. Although intrafascicular injections are rarely made, we recommend that intraneural injections of local anesthetics or other solutions close to the spine should be avoided, as they may cause unexpected spinal anesthesia or lesion of the cord.
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Acta Anaesthesiol Scand · Jan 1978
Acute effects of furosemide and mannitol on central haemodynamics in the early postoperative period.
The effects of furosemide and mannitol on central haemodynamics in the early postoperative period were investigated in 16 patients, who had undergone upper abdominal surgery. Measurements were performed prior to, and then 10, 30, 50 and 90 min after postoperative drug administration. ⋯ Systemic vascular resistance decreased. It is concluded that mannitol should be used as the diuretic of choice in the treatment of postoperative (post-traumatic) oliguria in patients without known cardiovascular disease.
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Acta Anaesthesiol Scand · Jan 1978
Cardiovascular effects of local adrenaline infiltration during halothane anaesthesia and adrenergic beta-receptor blockade in man.
Adrenergic beta-receptor blocking agents, alprenolol, propranolol and practolol were given as a prophylactic measure to patients undergoing middle-ear microsurgery where adrenaline was deliberately infiltrated during halothane-N2O/O2 anaesthesia. These three beta blockers did not differ in their action on heart rate, arterial blood pressure, right ventricular pressure, CVP or peripheral pulse wave in equipotent doses, which were 0.04 mg/kg for alprenolol and propranolol and 0.4 mg/kg for practolol in this study. ⋯ Occasionally occuring tachyarrhythmias were easily terminated with a further dose of a beta blocker. The effective half-life of practolol was less than 15 min and doses up to 0.4 mg/kg were unable to prevent arrhythmias during adrenaline challenge.