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In the March 2010 BJA…
British Journal of Anaesthesia 104 (3) (2010)
doi:10.1093/bja/aeq026
IN THIS ISSUE
In the March 2010 BJA. . .
Antiplatelet drugs and surgery There has been considerable interest and debate about the best perioperative management of patients on antiplatelet therapy, particularly clopidogrel, for recent coronary stent implants. In a study of 30 patients with recent stents, Savonitto et al. ( pages 285 – 91) used the short-acting antiplatelet agent tirofiban to ‘bridge’ the temporary withdrawal of clopidogrel. There was no stent thrombosis and no intraoperative bleeding problems. A similar debate has involved the perioperative use of aspirin and weighed the cardio-protective effects against the risk of bleeding. In a randomized, double blind, placebo-controlled trial comparing the effect of low-dose aspirin with that of placebo on myocardial damage, cardiovascular and bleeding complications in 220 high-risk patients undergoing non-cardiac surgery, aspirin (75 mg) or placebo was given 7 days prior to surgery and continued until the third postoperative day (Oscarsson et al., pages 305– 12). The incidence of major adverse cardiovascular events up to 30 days postoperatively was lower (1.8%) in the aspirin group than in the placebo group (9%).
Oxytocin and Caesarean section Oxytocin is used widely to increase uterine tone during Caesarean section and thus decrease blood loss. However, although a dose of 5 u is used frequently, there is limited evidence to substantiate this and adverse haemodynamic effects are known to occur after i.v. oxytocin. In a double-blind randomized study, Butwick et al. ( pages 338– 43) compared the effect on uterine tone of 0, 0.5, 1, 3, 5 u oxytocin. Interestingly, they found no significant difference between the groups at 2 min with adequate uterine tone being achieved in all groups (including 0 u). There was a much higher incidence of hypotension in the group receiving 5.0 u. The authors recommend that smaller doses (0.5 – 3 u) are used routinely.
Pain mechanisms Two laboratory based studies with human volunteers look at different aspects of pain mechanisms with the aim of improving our understanding of these and providing additional modes for analgesia. There is some evidence that cholinesterase inhibitors may have a role in analgesia. A study of 20 volunteers (Wehrfritz et al., pages 359 – 68) given alfentanil, physostigmine and a combination of the two showed reduction of pain intensity of 35%, 50% and 60%, respectively, suggesting a distinct (non-additive) effect for physostigmine. There is evidence that xenon acts on NMDA receptors. In a study of 10 volunteers, Froeba et al. ( pages 351 – 8) found that a low dose of xenon (1 litre h21) given nasally, significantly increased pain tolerance. The authors suggest that this drug and route of administration are worthy of further investigation.
# The Author [2010]. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: [email protected]
doi:10.1093/bja/aeq026
IN THIS ISSUE
In the March 2010 BJA. . .
Antiplatelet drugs and surgery There has been considerable interest and debate about the best perioperative management of patients on antiplatelet therapy, particularly clopidogrel, for recent coronary stent implants. In a study of 30 patients with recent stents, Savonitto et al. ( pages 285 – 91) used the short-acting antiplatelet agent tirofiban to ‘bridge’ the temporary withdrawal of clopidogrel. There was no stent thrombosis and no intraoperative bleeding problems. A similar debate has involved the perioperative use of aspirin and weighed the cardio-protective effects against the risk of bleeding. In a randomized, double blind, placebo-controlled trial comparing the effect of low-dose aspirin with that of placebo on myocardial damage, cardiovascular and bleeding complications in 220 high-risk patients undergoing non-cardiac surgery, aspirin (75 mg) or placebo was given 7 days prior to surgery and continued until the third postoperative day (Oscarsson et al., pages 305– 12). The incidence of major adverse cardiovascular events up to 30 days postoperatively was lower (1.8%) in the aspirin group than in the placebo group (9%).
Oxytocin and Caesarean section Oxytocin is used widely to increase uterine tone during Caesarean section and thus decrease blood loss. However, although a dose of 5 u is used frequently, there is limited evidence to substantiate this and adverse haemodynamic effects are known to occur after i.v. oxytocin. In a double-blind randomized study, Butwick et al. ( pages 338– 43) compared the effect on uterine tone of 0, 0.5, 1, 3, 5 u oxytocin. Interestingly, they found no significant difference between the groups at 2 min with adequate uterine tone being achieved in all groups (including 0 u). There was a much higher incidence of hypotension in the group receiving 5.0 u. The authors recommend that smaller doses (0.5 – 3 u) are used routinely.
Pain mechanisms Two laboratory based studies with human volunteers look at different aspects of pain mechanisms with the aim of improving our understanding of these and providing additional modes for analgesia. There is some evidence that cholinesterase inhibitors may have a role in analgesia. A study of 20 volunteers (Wehrfritz et al., pages 359 – 68) given alfentanil, physostigmine and a combination of the two showed reduction of pain intensity of 35%, 50% and 60%, respectively, suggesting a distinct (non-additive) effect for physostigmine. There is evidence that xenon acts on NMDA receptors. In a study of 10 volunteers, Froeba et al. ( pages 351 – 8) found that a low dose of xenon (1 litre h21) given nasally, significantly increased pain tolerance. The authors suggest that this drug and route of administration are worthy of further investigation.
# The Author [2010]. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: [email protected]