Spinal Anesthesia and Severe Gestational Hypertension Dr. Alison Macarthur Department of Anesthesia University of Toronto

Outline t Review of population / current obstetric practices t Methods of anesthesia for cesarean delivery (past / present) t Suggestions for future practice

Classification of PIH

Incidence of Complicated Gestational Hypertension t Incidence of GH: (U.S ) 26 / 1000 live births t contrast this with other nations: 20.3 / 1000 live births (Taiwan ) 103 / 1000 live births (Turkey 1986) t Incidence of severe disease: 5.2 / 1000 live births (U.S. 1986) 7.8 / 1000 live births (Taiwan )

Incidence of Gestational Hypertension t Incidence of eclampsia: 0.56 / 1000 live births (U.S.) 19 / 1000 live births (Turkey) t Mortality: (U.S ) 1.5 / 100,000 live births

Spinal anesthesia - introduction into practice t Obstetric anesthesiologists started using spinal anesthesia for cesarean delivery (1990’s) in mild - moderate disease t change from 1 st to 2 nd ed. Chestnut’s Obstetric Anesthesia: “Some anesthesiologists consider spinal anesthesia contraindicated in preeclampsia because of the risk of severe hypotension.”…

Old Evidence

Hood - Hemodynamic results Epidural Spinal

Wallace - Hemodynamic results

Karinen - Fetal Outcome (Pulsatility index)

New Evidence SOAP 2001; A34

Spinal Anesthesia for Eclamptics t No. of antepartum eclamptic parturients requiring immediate delivery: 1505 / 1846 (81.5%) t No. of cesarean deliveries: 1185 / 1505 (78.7%)

Spinal Anesthesia for Eclamptics t Method of anesthesia for cesarean delivery: 915 / 1185 spinal anesthesia (77.2%) 270 / 1185 general anesthesia (22.8%)

Spinal Anesthesia for Eclamptics t No. of deaths amongst women requiring LSCS delivery: 58 / 1505 (3.9%) [total deaths = 176 / 1846 (9.5%) ]

Spinal Anesthesia for Eclamptics t No. of deaths by method of anesthesia: spinal = 31 / 915 (3.4%) general = 27 / 270 (10%) t Odds Ratio (general / spinal) 3.17 (95% C.I. 1.86, 5.41)

Spinal Anesthesia for Eclamptics - Remaining Questions? 1. What factors determined type of anesthetic? 2. What were the causes of death in each group? 3. Where there complications in each group? 4. Not all the women with antepartum eclampsia (1846) delivered (1505). What happened to these women?

New Evidence Regional Anesthesia and Pain Medicine 2001; 26: 46-51

Ramanathan - Study Methods t Design: case series of 46 women, severe preeclampsia receiving CSE for cesarean delivery t Intervention: intrathecal bupivicaine 7.5 mg + fentanyl 25 mcg (+ epidural lidocaine 2%)

Ramanathan - Study Methods t Outcomes: BP, Ephedrine doses, Apgar score, umb ABG t Results: –8% epidural supplementation / 34% prior to closure –median sensory level T4 (T2-T5) –52% req’d ephedrine use, nadir w/i 5 min of spinal

Ramanathan - Hemodynamic changes SBPDBPMAP

Comments: Dr. Hood t Oral exam preparation: does the clinical scenario leave time for an epidural? t Urgent clinical scenario: spinal anesthetic t Residents taught to use spinal anesthesia t 2/ OAA meeting use spinal anesthetics

Personal Pearls t Choosing patient: consider airway, bleeding diathesis, neurological status, urgency t Methods: hyperbaric bupivicaine 0.75% mg preservative-free morphine mg t Consider intra-arterial monitor t Pre-determine % change in MAP or systolic bp to respond with vasopressor

Conclusions Future research: Await RCT …… however……. 1. Changing obstetric practice: 327 / 444 (73.6%) labored 2. Lack of clinical equipoise: “.....we could not do a randomised epidural versus spinal trial for severe pre-eclamptics.”

Future Studies t Sophisticated evaluation of fetal / neonatal wellbeing during course of regional anesthesia t Continued reporting of observational data (specifically: morbidity)

Conclusion t … are not to convince that spinal anesthesia should replace epidural anesthesia t instead…. to convince you that spinal anesthesia should be an option instead of general anesthesia