Diabetic parturients can be classified either:
(1) according to White's classification (Table 81.1) (1), or
(2) according to the universal classification
(Type 1: insulin dependent, Type 2: non-insulin dependent).
Because White's classification is based mainly on the duration of diabetes and the extent of organ involvement it immediately conveys to anesthesiologists the nature and severity of the diabetic state.
Major maternal problems include:
(1) Hypertension with associated nephropathy or pre-eclampsia,
(2) Impairment of the normal hemodynamic adjustments to pregnancy due to preclinical diabetic cardiomyopathy and subclinical autonomic neuropathy (2),
(3) Impairment of uteroplacental blood flow (UPBF) in diabetic parturients. UPBF can be further decreased in the presence of a high blood glucose. Aggressive treatment of maternal hypotension is very important, and,
(4) Prolonged exposure to an elevated blood sugar level leads to an increased hemoglobin A1C (Hb A1C) in diabetic parturients (3). The correlation between Hb A1C and Fasting Blood Sugar (FBS) is illustrated in Figure 81.1. Hb A1C is a poor oxygen carrier and the chances of hypoxia in the fetus will increase if the maternal diabetes is not properly controlled.
Major fetal problems include:
(1) The occurrence of severe intrauterine growth retardation (lUGR) due to decreased placental perfusion as well as increased maternal HbA1C. These babies may be very sensitive to reduced placental perfusion due to maternal hypotension. At the other extreme, management of fetal macrosomia may be a real challenge (4). Shoulder dystocia can complicate vaginal delivery and accidental extension of the uterine incision can occur during difficult abdominal delivery. These extremes of growth abnormality are shown in Figure 81.2. The infant on the left has severe IUGR (470g) and the one on the right has macrosomia (5100g).
(2) Major fetal congenital anomalies may be associated with uncontrolled maternal diabetes.
Anesthetic Management:
Labor and Delivery
Epidural analgesia for labor and delivery is associated with obvious advantages:
(1) It can indirectly increase uteroplacental blood flow by decreasing the endogenous catecholamine concentrations,
(2) It will reduce the maternal lactic acid production, and, hence, reduce fetal acidosis,
(3) It will provide excellent pain relief during the first, as well as the second, stage of labor, especially during a difficult delivery, and
(4) The existing epidural catheter can be used should an emergency cesarean section be necessary.
Cesarean Section
Although both spinal and epidural anesthesia can be used with good neonatal outcome, epidural anesthesia may be preferable in patients with longstanding diabetes for maintenance of cardiovascular stability. Regional anesthetic management for cesarean section for diabetic parturients should include:
(1) acute hydration with non-dextrose solution,
(2) routine left uterine displacement,
(3) prompt treatment of hypotension with intravenous ephedrine (5).
Because there are some suggestions of abnormal hemodynamic adjustments from associated diabetic cardiomyopathy and autonomic neuropathy in long-standing diabetic parturients, careful volume expansion may be necessary. Epidural anesthesia may be the preferable technique for cesarean section.
Stiff joint syndrome (diabetic scleredema) is a recognised cause of difficult intubation and has been associated with anterior spinal artery syndrome following administration of epidural anesthesia in a parturient with this condition (6). A rigid epidural space associated with reduced spinal cord circulation from administration of a large volume of local anesthetic was the postulated mechanism. Judicious use of a reduced volume of epidural local anesthetic is indicated in these cases.
References:
1. White P. Pregnancy complicating diabetes. Am J Med 1949; 7:609-616.
2. Airaksinen KEJ, Ikaheimo MJ, Slmea PI, et al. Impaired cardiac adjustment to pregnancy in Type I diabetes. Diabetes Care 1986; 9:376-382.
3. O'Shaughnessy R, Russ J, Zuspan FP. Glycosylated hemoglobins and diabetes mellitus in pregnancy. Am J Ob Gyn 1979; 135:783-790.
4. Landon MB. Diabetes mellitus and other endocrine diseases. In Gabbe SG, Niebyl JR, Simpson JL (eds): Obstetrics: normal and problem pregnancies. New York 1991, pp. 100.
5. Datta S, Kitzmiller JL, Naulty JS, et al. Acid-base status of diabetic mothers and their infants following spinal anesthesia for cesarean section. Anes Analg 1982; 61:662.
6. Eastwood DW. Anterior spinal artery syndrome after epidural anesthesia in a pregnant diabetic patient with scleredema. Anes Analg 1991; 73:90-91.