British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Effects of clonidine premedication on the pressor response to alpha-adrenergic agonists.
It has been suggested that postjunctional alpha 1-adrenoceptor mediated vasoconstriction is enhanced by clonidine. We have examined in humans if the pressor responses to noradrenaline and phenylephrine are enhanced by clonidine premedication. Seventy-seven patients were allocated randomly to either clonidine (n = 38) or control (n = 39) groups. ⋯ When a stable haemodynamic state was obtained, either noradrenaline 0.5 microgram kg-1 (n = 40) or phenylephrine 2 micrograms kg-1 (n = 37) was administered randomly i.v. as a bolus, while arterial pressure and heart rate were measured noninvasively at 1-min intervals for 10 min. Although noradrenaline caused significantly greater increases in mean arterial pressure (MAP) in the clonidine group (from 2 to 4 min after i.v. injection) compared with the control group, there were no significant differences in the mean maximal increment in MAP or area under the MAP curve between the two groups. However, i.v. phenylephrine produced a significantly greater increase in MAP from 2 to 7 min (P < 0.05), and greater mean maximal increase in MAP from the baseline value (21 (9) vs 14 (7) mm Hg; P < 0.05) in the clonidine than in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)
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Comparative Study
Evaluation of the Pneupac Ventipac portable ventilator: comparison of performance in a mechanical lung and anaesthetized patients.
The performance of the Pneupac Ventipac portable gas-powered ventilator was evaluated in two stages. The accuracy of delivery of the ventilator was assessed using a mechanical lung model at different combinations of compliance and airway resistance to simulate normal and diseased lungs. The performance of the ventilator was then assessed in 20 anaesthetized patients. ⋯ Delivered tidal volume was between -19 and +12% of the present tidal volume in the group of anaesthetized patients using the ventilator in airmix mode. The ventilator was reliable and simple to use, and performance was within acceptable limits in the anaesthetized patients. However, we recommend that a means of verifying the adequacy of ventilation should always be used when transporting critically ill or anaesthetized patients with any portable ventilator, particularly when lung compliance or airway resistance may be abnormal.
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Randomized Controlled Trial Comparative Study Clinical Trial
Extradural, paravertebral and intercostal nerve blocks for post-thoracotomy pain.
Forty-five patients were allocated randomly to receive either a single intrathoracic block of four intercostal nerves, a continuous thoracic extradural infusion or a continuous paravertebral infusion of bupivacaine. Patients were allowed additional i.v. boluses of morphine via a PCA device. ⋯ There were no significant differences between the groups in pain, morphine consumption, respiratory function or adverse events. Moderate to severe respiratory depression was detected in 14 patients more than 2 h after operation.
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Randomized controlled studies were reviewed to assess the effectiveness and safety of antiemetics used for prophylaxis in paediatric strabismus surgery. Early and late vomiting (6 and 48 h after operation, respectively), and adverse effects were evaluated using the numbers-needed-to-treat method. In 27 reports with information on 2033 children, the mean incidence of early vomiting was 54% and of late vomiting 59%, without prophylaxis. ⋯ Metoclopramide 0.15 and 0.25 mg kg-1 was significantly better than control only for early vomiting. Propofol had a high incidence of oculocardiac reflex without conferring any significant antiemetic effect: it should not be used. The benefits of prophylactic antiemetic therapy are not proven.
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Randomized Controlled Trial Comparative Study Clinical Trial
Effect of crystalloid and colloid preloading on uteroplacental and maternal haemodynamic state during spinal anaesthesia for caesarean section.
We have studied the effects of crystalloid 1 litre (lactated Ringer's) or colloid 0.5 litre (hydroxyethyl starch) preloading in 26 healthy parturients undergoing elective Caesarean section under spinal anaesthesia. Maternal placental uterine artery circulation was measured using a pulsed colour Doppler technique with simultaneous measurement of maternal haemodynamics. A high incidence of maternal hypotension was observed during spinal anaesthesia in the crystalloid group (62%) but the incidence was lower in the colloid group (38%). ⋯ These individual increases in PI were transient and always returned to baseline values within 2 min. These results suggest that preloading with either solution is ineffective in preventing maternal hypotension and that changes in maternal heart rate, systolic arterial pressure and central venous pressure during spinal anaesthesia were not associated with rapid individual increases in uteroplacental vascular resistance. These changes seemed not to have any major effect, however, on the clinical condition of the newborn, as assessed by Apgar scores and umbilical artery pH values.