In the early postpartum period, the unwary may attribute unexplained hypotension to sympathetic block (from neuraxial blockade) rather than to bleeding. The important causes of PPH are outlined in Table 74.1. Once a diagnosis of PPH has been made, the patient must be rapidly assessed (Table 74.2) and volume replacement and other resuscitative measures must be initiated in earnest (Table 74.3).
A number of drugs are available to limit the degree of bleeding. The most common cause of PPH is uterine atony and the most important agents which can enhance uterine contraction and increase uterine tone or reinitiate contractions are:
1. Oxytocin, eg. Synthetic oxytocin (Syntocinon) administered as a 5 to 10 International Units (IU) bolus slowly IVI followed by an infusion of 10 to 20 IU (some recommend doses as high as 50 IU) syntocinon in 1000 mL 4% dextrose in 1/5N Saline or an isotonic electrolyte solution at 250 mL/hr. Occasionally, the vasodilatation produced by a bolus of syntocinon can produce profound hypotension and reflex tachycardia (1, 2, 3, 4, 12).
2. Prostaglandin, eg. 15-methyl analogue of prostaglandin (PG) F2-alpha (Prostinfenem) 0.25 mg IV in 500 ml 5% dextrose. PG E2-alpha (Prostin E2-alpha) can be used by intrauterine irrigation, rectal suppositories or vaginal pessaries or gel. PG F2-alpha (Prostin F2-alpha, 1 to 5 mg.) should be used intramyometrially because of its extensive multisystem effects. Prostinfenem (250 to 500 mcg) can also be used by this route. Systemic prostaglandins can cause pulmonary oedema, hypotension or hypertension and should be avoided in those with hypertensive heart disease or severe pre-eclampsia. Bronchospasm is also not uncommon so that its use in asthmatics is contraindicated (5, 6, 7, 8, 9, 14).
3. Ergot, eg. Methylergobasin (Ergometrine) 1 to 2 mg. slowly IV or, methylergonovine (Ergonovine) up to 0.2 mg. very slowly IVI or 0.2 to 0.3 mg. IMI. Ergometrine (4 to 6 mg.) can also be injected directly into uterine muscle. Ergometrine can produce peripheral vasoconstriction and further compromise organ perfusion (eg. myocardial ischaemia can occur) (2, 3, 13).
More rarely, PPH is due to a coagulopathy. In selected cases the following pharmacological agents may be useful: 1. Desmopressin acetate (DDAVP) in those with a platelet function abnormality (10). 2. Epsilon aminocaproic acid (EACA, Amicar) in those with disseminated intravascular coagulation.
References:
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