The initial dose of labetalol, when it is your chosen agent, is 20 mg IV, with BP measured 10 minutes later. If the target BP threshold is not achieved, administer 40 mg, 80 mg, and 80 mg at 10-minute intervals, as needed, again measuring BP 10 minutes after every dose. If, after a maximum dose of 240 mg, the desired BP threshold still has not been reached, give 5 to 10 mg IV hydralazine and measure BP 20 minutes later. If the target BP threshold still has not been achieved, it is essential to obtain consultation on the need for continuous infusion of labetalol, nicardipine, or sodium nitroprusside.
The initial dose of hydralazine, when it is your chosen agent, is 5 to 10 mg IV, with BP measured 20 minutes later. If needed, give another 10 mg and measure BP after another 20-minute interval. After a maximum dose of hydralazine 20 mg, switch to IV labetalol, using the regimen described above for labetalol, if the BP threshold still has not been achieved.
This drug is an arterial—but mostly venous—dilator. It is administered via IV infusion at an initial rate of 5 µg/min, with the rate gradually increased every 3 to 5 minutes (titrated to BP) to a maximum dose of 100 µg/min. It is the drug of choice in any hypertensive emergency associated with pulmonary edema and for control of hypertension associated with tracheal manipulation during intubation and extubation with general anesthesia.
Nitroglycerin is contraindicated in hypertensive encephalopathy because it increases cerebral blood flow and intracranial pressure. This drug should be administered only under the supervision of an experienced obstetric intensivist.
This agent causes arterial and venous relaxation by interfering with the influx and intracellular activation of calcium. It is the drug of choice in hypertensive encephalopathy because it controls both afterload (vascular resistance) and preload (fluid status). It should be used only in the setting of intensive care.
The recommended dose is IV infusion at a rate of 0.25 to 5.00 µg/kg/min. Sodium nitroprusside has an immediate onset of action and may continue to exert an effect 3 to 5 minutes after discontinuation. Any hypotension caused by the drug should subside within minutes after discontinuation of the drip, due to the drug’s short half-life.
Nitroprusside is metabolized into thiocyanate and excreted in the urine. Cyanide can accumulate with large doses (>10 µg/kg/min) or prolonged administration (>48 hours), or if the patient has renal insufficiency or decreased hepatic metabolism. Signs of toxicity include anorexia, disorientation, headache, fatigue, restlessness, tinnitus, delirium, hallucinations, nausea, vomiting, and metabolic acidosis. When infused at a rate of less than 2 µg/kg/min, however, cyanide toxicity is unlikely.
As is the case with nitroglycerin, this drug should be administered only under the supervision of an experienced obstetric intensivist.
Upon arrival at the ED, the patient exhibits shallow, rapid breathing and foaming from the mouth. She is placed in a lateral decubitus position, an oral airway is established, and all secretions are suctioned. Oxygen is administered via face mask at a rate of 8 L/min. Her initial oxygen saturation level is 92%. IV access is secured, and a loading dose of magnesium sulfate 6 g is given over 20 minutes. Oxygen saturation increases to 94% to 96%. Auscultation of both lungs is normal.
The patient remains in a postictal state for about 15 minutes, but then orients to name, place, and time. FHR monitoring of both fetuses reveals a normal baseline with moderate variability, as well as variable decelerations in the presenting twin.
A maintenance dose of magnesium sulfate is initiated at a rate of 2 g/h, with the BP level recorded every 15 minutes. Systolic values remain between 170 and 180 mm Hg, and diastolic values between 108 and 112 mm Hg for 60 minutes. The obstetrician administers IV labetalol (20 mg) over 2 minutes. About 15 minutes later, the BP level is 154/100 mm Hg, with values remaining in the range of 150 to 156 mm Hg systolic and 92 to 104 mm Hg diastolic.
Ultrasonography reveals that the presenting twin is in a breech position, with estimated fetal weight below the 10th percentile and oligohydramnios. As a result, the obstetrician elects to proceed to cesarean delivery. The twins are delivered by cesarean section using spinal anesthesia. Although the infants are premature, there are no complications.Witnessing an eclamptic convulsion can be a frightening experience for nurses and medical providers. The convulsion usually lasts 60 to 90 seconds and occurs in two phases:
- Phase 1 (15–25 seconds) involves facial twitching, rolling of the eyes, and stiffening of the body, with generalized muscular contractions.
- Phase 2 (20–50 seconds) involves alternate contraction and relaxation of the muscles of the body in rapid succession, starting in the face and spreading throughout the body. Foaming at the mouth also occurs, and the patient may bite her tongue if it isn’t protected.
Apnea develops during and immediately after the convulsion, lasting about 120 seconds. A period of hyperventilation follows to compensate for the respiratory acidosis during the apneic period.
A postictal state follows the convulsion, and the patient usually remembers nothing of the episode. Some patients also become restless, combative, and agitated, requiring sedation. Aspiration is possible during or after the convulsion.
