Plasma exchange: an option for the treatment of life-threatening status asthmaticus in pregnancy.

Status asthmaticus during pregnancy is a rare but lifethreatening condition for the mother and foetus. Some authors favour the termination of pregnancy by caesarean section, while others have succeeded in saving the life of both the mother and the baby by the use of artificial ventilation in addition to conventional drug therapy. We report our experience with a rather unusual approach for the treatment of drug-resistant status asthmaticus with respiratory failure in a 37-yr-old pregnant female. Following many years of stable allergic seasonal asthma, the patient experienced a severe asthmatic attack following a positive pregnancy test at home. The emergency was overcome by i.v. corticosteroids (250 mg) and theophylline (200 mg). When the pregnancy with a gestational age of 13 weeks was confirmed by an obstetrician 3 days later, the patient experienced a relapse of her asthma and was admitted to her community hospital in severe respiratory distress. Her respiratory condition deteriorated despite immediate treatment using high doses of selective b2-agonists and anticholinergic compounds, i.v. theophylline, corticosteroids and sodium bicarbonate. Obvious physical exhaustion, signs of hyperventilation and respiratory acidosis (arterial oxygen tension (Pa,O2)=11.6 kPa (87 mmHg), arterial carbon dioxide tension (Pa,CO2) =9.2 kPa (69 mmHg), standard bicarbonate=25 mval.L, base excess=2.9 mval.L, pH=7.24, respiratory frequency 35 breaths.min) necessitated orotracheal intubation and artificial ventilation on the day after admission (day 2) (fig. 1). Despite profound sedation, muscle relaxation and repetitive bronchial lavage, the respiratory situation did not stabilize. The following selected drugs given to the patient (weight=52 kg) on this 3rd day after admission (May 14th) illustrate her outstanding drug requirements: ketamine 2,330 mg.day, diazepam 160 mg.day, pancuronium 72 mg.day, prednisone 2 g.day, reproterol 0.45 mg.day, theophylline 1.7 g.day and clemastin 11 mg.day. After counselling with an obstetrician, an anaesthesiologist, a neonatologist and the patient's husband, a decision was made to give the patient every possible treatment irrespective of the baby's fate. Although Pa,O2 had stabilized above normal, Pa,CO2 continued to be elevated and varied according to the state of sedation or relaxation. Of particular concern were the progressively increasing inspiratory pressures required to maintain the tidal volume. On the 3rd day of the ongoing status asthmaticus, it was decided to apply plasma exchange as an ultimate therapeutic regimen (fig. 1). Based on theoretical grounds, our previous unpublished experience and anecdotal reports [1, 2], we attempted to eliminate circulating antigens and/or immunoglobulin E (IgE) which were supposed to be responsible for the sustained asthmatic response. Informed consent was obtained from the patient's husband. Matching with the estimated blood volume (2.95 L), on each of the 3 consecutive days, 3±3.5 L of plasma was exchanged via a double-lumen Sheldon catheter inserted in the right femoral vein. No technical or clinical complications occurred with these procedures. Immediately after the first plasma exchange (day 3) the patient's clinical and respiratory function improved. The inspiratory pressures decreased dramatically, resulting in an increase in minute volume and concomitant drop in Pa,CO2 (fig. 1). However, there were additional benefits,