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Re: Eclampsia From: JOHN ANTHONY (anthonyj@uctgsh1.uct.ac.za) Thu Mar 28 00:24:40 1996 Messages sorted by: [ date ][ thread ][ subject ][ author ] Next message: Bert Gold: "HCFA PLAN TO CLOSE HOSPITALS?" Previous message: Roland Armstrong: "Re: Health Options" Maybe in reply to: Dr. Carlos Chase: "Eclampsia" Next in thread: Lynn D. Montgomery: "Re: Eclampsia" Dear Dr Montgomery In your reply to Dr Lisse, you wrote , > I am sorry to hear that you have such a difference with epidural management > of an eclamptic patient. Let me address these concerns with some facts. > > Hodgkinson et al have investigated the systemic and pulmonary arterial > pressure and PCWP that occur during induction of general anesthetic and > epidural anesthetic in patients with severe pregnancy induced hypertension. > They found that there were minimal changes in the parameters with epidural. > However, with induction of general anesthetic, they noted a increase in the > mean arterial pressure of 45mm Hg, in the mean pulmonary artery pressure of > 20mm Hg and in the PCWP of 20mm Hg. (Hodgkinson, et al: Systemic and > pulmonary blood pressure during caesarean section in parturients with > gestational hypertension. Can Anaesth Soc J 1980; 27:389) > > There is significantly less risk of airway complications associated with > epidural anesthesia. Laryngeal edema can result in difficulty with the airway. > Epidural anesthesia actually lessens the risk of aspiration associated with > general anesthesia. (Joupilla, et al: Laryngeal oedema as an obstetric > anaesthesia complication. Acta Anaesth Scand 1980; 24:97. Seager, et al: > Laryngeal oedema and preeclampsia. Anaesthesia 1980; 35:360. Heller, et > al: Pharyngolaryngeal edema as a presenting symptom in preeclampsia. > Obstet Gynecol 1983; 62:523) > > Further, epidural anesthesia improves intervillous blood flow by decreasing > uterine vascular resistance. (Hollmen, et al: Regional anesthesia and > uterine blood flow. Ann Chir et Gynaecol 1984; 73:149) Postoperatively, > epidural lessens the catecholamine response associated with pain, therefore > lessening the systemic vascular resistance. > > Finally in Critical Care Obstetrics, Clark, et al, it is stated, "Most > obstetrical anesthesiologists prefer epidural analgesia for providing pain > relief for PIH patients. Contraindications to regional analgesia include > (a) the presence of a coagulopathy (prolonged PT or PTT, platelet count < > 100,000 mL or fibrinogen level < 150mg/dL, (b) uncorrected hypovolemia, (c) > infection, and(d) patient refusal." > > In regard to the time it takes to administer an epidural, this was studied > at the institution where I trained. Despite the notion that a general > anesthetic is faster, it indeed was no faster than administration on an > epidural. > > In conclusion, given these proven facts, it would seem that when one has a > choice between regional or general anesthetic in a preeclamptic/eclamptic > patient, the logical choice would be regional. > Firstly, may I say that where there is such diversity of opinion on the subject, I am puzzled to see such a definite dividing line being drawn between what is "right" and what is "wrong". You quote "facts" each of which in their own right merit critical scientific examination. I run an obstetric critical care unit that receives referrals from a pool of approximately 30 000 deliveries per annum. Our unit has a 1% utilisation rate, the commonest reason for admission being pre-eclampsia. We do a lot of invasive monitoring (recent audit published Johanson R, Anthony J, Dommisse J: J Obstet Gyanecol 1995; 15(3) 174 - 178), and I must say that despite our volume of pathology, I am considerably less certain than you about the safety of regional anaesthesia. Lets us get around to your "facts": 1. Yes, intubating patients leads to a hypertensive surge. However there are ways of successfully obtunding this response using alfentanyl and bolus dose magnesium sulphate at the time of induction (see Allen RW, James MF, Uys PC Attenuation of the pressor response to tracheal intubation in hypertensive proteinuric pregnant patients by lignocaine, alfentanil and magnesium sulphate. Br J Anaes 1991; 66(2), 216 -223). 2. Laryngeal oedema: this cannot be divorced from considerations revolving around airway management as a whole - ie the prevention of aspiration either in consequence of general anaesthesia or because of seizures. In the case of eclamptic patients - and this is what this discussion has been about - regardless of the general undesirability of intubation - the question of preventing recurrent seizures and the accompanying risk of aspiration must be addressed. This includes the intraoperative period. 3. The supposition that vasodilatation (of any description) will improve choriodecidual perfusion is suspect. Measuring uterine blood flow accurately is notoriously difficult and looking at simple haemodynamic changes where vasodilatation is the sole intervention does not necessarily lead to improved perfusion (see Wallenburg HCS. Hemodynamics in hypertensive pregnancy. Handbook of Hypertension, Vol 10: Hypertension in pregnancy. Rubin PC (ed). Elsevier Science). Beyond Wallenburgs observations should also lie the realisation that the nature of the pathology seen in the spiral arteries is such that intraluminal changes may partially obstruct these vessels and contribute to distal ischaemia and that vasodilatation alone cannot reverse these changes and that a certain (increased) head of perfusing pressure may be necessary to maintain perfusion (see June 1996 edition Current Obstetrics and Gynaecology Anthony J Johanson R: Critical care in pregnancy). 4. Clarks opinion re Obstetric anesthesiologists remains just that - opinion. In practising clinical medicine, we all have to make choices; hopefully those choices will be based on scientific evidence; where the evidence is lacking we may have to rely on intuition. That we do so is inevitable but let us never forget that we are acting on intuition alone and that those practices guided by opinion should not become entrenched dogma and a barrier to free thought and change when better evidence comes along. Finally may I say that the biggest problem I have with regional anaesthesia for pre-eclampsia arises from concern about plasma volume expansion - I have addressed that in a previous e-mail and my views are further set out in Critical Care management of severe pre-eclampsia (Anthony J, Johanson R, Dommisse J: Fetal and Maternal Medicine Review 1994; 6: 219 - 229). I therefore remain concerned that the evidence either in favour of or against the use of epidural anaesthesia is inconclusive and that we should all keep an open mind rather than adopting a rigid attitude to the issue. Regards -- John Anthony Dr John Anthony Maternal and Fetal Medicine Unit Groote Schuur Hospital Department of Obstetrics and Gynaecology University of Cape Town Telephone 021 404 2380 Fax 021 448 6921 Next message: Bert Gold: "HCFA PLAN TO CLOSE HOSPITALS?" Previous message: Roland Armstrong: "Re: Health Options" Maybe in reply to: Dr. Carlos Chase: "Eclampsia" Next in thread: Lynn D. Montgomery: "Re: Eclampsia"

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