Can I use a block?
Dr Andrew Buettner
Deputy Director Anaesthesia
Royal Women's Hospital
Melbourne
Conclusions
Serious outcomes of regional analgesia/anaesthesia in obstetric practice are extremely rare.[1] This is very reassuring but leads to uncertainty as to the safest course of action when confronted with a difficult clinical problem, as there is often little evidence to inform our approach. These problems are not usually amenable to RCTs as the numbers needed are extremely large so we fall back on case studies or series or expert opinion.
Issues that will be addressed in this presentation include the use of regional anaesthesia/analgesia for the febrile pregnant patient, in the parturient with thrombocytopenia and on LMWH as well as situations where regional anaesthesia was considered contraindicated such as placenta praevia or restricted such as preeclampsia.
As a registrar I was told not to insert an epidural into a woman with a temperature over 38.5.
Is there any basis for this?
The use of regional analgesia/anaesthesia in febrile parturients has always been a concern because of the risk of causing an epidural abscess or meningitis.
Fever is usually a sign of infection. The most common causes of infection in a parturient are chorioamnionitis, urinary tract and respiratory infections.[2]
Blanco et al found an incidence of bacteremia of 7.5 per 1000 obstetric admissions. There was no correlation between the severity of fever and the incidence of bacteremia. 49% of patients with proven bacteremia had a temperature of less than 38.8C.[3] Setting arbitrary temperature limits in the hope of distinguishing between bacteremic and non bacteremic patients is ineffective. In a retrospective study of over 500 patients with culture proven chorioamnionitis who received epidural or spinal anaesthesia there were no reports of any infective complications such as epidural or spinal abscesses or meningitis.[4]
Viral infections particularly HSV 2 and HIV are another cause of concern to the anaesthetist mainly due to the possibility of introducing neuraxial spread of the virus.
There remain concerns with primary HSV 2 infections. HIV and regional anaesthesia has been more extensively studied. Our current understanding is that HIV infection is already present in the CNS from the early stages. Regional anaesthesia has been studied prospectively in parturients with HIV without any neurological sequalae.[5]
Thrombocytopenia is another problem encountered during pregnancy that lends itself to dogmatic assertions of safe versus unsafe levels. Thrombocytopenia during pregnancy is most commonly due to gestational thrombocytopenia, hypertensive disorders such as preeclampsia or ITP. Rather than focusing on a raw number it is more important to consider whether there is a deficit in platelet function as well as number. It is also important to look at the pattern of decrease over time. There are now numerous reports of safe regional anaesthesia in parturients with low platelet counts. There is no arbitrary cut off level for safety. Each case needs to be considered individually with regards to the potential benefits and risks for that patient.
Severe preeclampsia remained as the last bastion of epidural anaesthesia for caesarean section until recently. There were concerns that the use of spinal anaesthesia may lead to unstable haemodynamics in this already compromised group. There is now good evidence at a RCT level that spinal anaesthesia is well tolerated in severe preeclampsia and can be used safely.[6]
High grade placenta praevia also has remained one of the few indications for the use of general anaesthesia at caesarean section. This too has been challenged by more recent experience which suggests that regional anaesthesia can be used safely even in the presence of known placenta percreta.[7, 8]
1. Ruppen W, Derry S, McQuay H, Moore RA. Incidence of epidural hematoma, infection, and neurologic injury in obstetric patients with epidural analgesia/anesthesia.. Anesthesiology 2006;105(2):394-9.
2. Kuczkowski KM, Reisner LS. Anesthetic management of the parturient with fever and infection. Journal of Clinical Anesthesia 2003;15(6):478-88.
3. Blanco JD, Gibbs RS, Castaneda YS. Bacteremia in obstetrics: clinical course. Obstetrics & Gynecology 1981;58(5):621-5.
4. Goodman EJ, DeHorta E, Taguiam JM. Safety of spinal and epidural anesthesia in parturients with chorioamnionitis. Regional Anesthesia 1996;21(5):436-41.
5. Hughes SC. HIV and pregnancy: twenty-five years into the epidemic. International Anesthesiology Clinics 2007;45(1):29-49.
6. Visalyaputra S, Rodanant O, Somboonviboon W, Tantivitayatan K, Thienthong S, Saengchote W. Spinal versus epidural anesthesia for cesarean delivery in severe preeclampsia: a prospective randomized, multicenter study. Anesthesia & Analgesia;101(3):862-8.
7. Parekh N, Husaini SW, Russell IF. Caesarean section for placenta praevia: a retrospective study of anaesthetic management. British Journal of Anaesthesia 2000;84(6):725-30.
8. Fuller AJ, Carvalho B, Brummel C, Riley ET. Epidural anesthesia for elective cesarean delivery with intraoperative arterial occlusion balloon catheter placement. Anesthesia & Analgesia 2006;102(2):585-7.
Time of Presentation
1330
