H1N1 with adult respiratory distress syndrome for emergency lower segment cesarean section: A case report.

Sir,

A 21 years old, 36 weeks parturient presented with fever, cough, and breathlessness of 5-6 days duration with heart rate (HR): 120/min, blood pressure (BP): 120/70 mmHg, respiratory rate (RR): 32/min, temperature: 103.2 F and oxygen saturation (SpO2) of 92-93% with 10 L of oxygen. She had coarse crepitations in all lung fields. Arterial blood gas (ABG) showed: pH −7.462, pCO2 −19.8, pO2 −64.3, bicarbonate −14, base excess −7.5, SpO2 −91.3 lactate – 1.3.

She was started on noninvasive ventilation. Oseltamivir 75 mg was started since polymerase chain reaction test on throat swab revealed H1N1. She showed improvement in oxygenation on the 2nd day, but went into premature labor for which emergency lower segment cesarean section was decided upon. Uterine relaxant to delay labor could not be used as it causes shortness of breath and tachycardia.

On arrival, her HR was 120/min, BP: 120/70 mmHg, SpO2: 91%, and RR: 36/min. After preoxygenation with 100% oxygen for 3 min, rapid sequence induction was done with intravenous (IV) propofol 60 mg and ketamine 40 mg and succinylcholine 100 mg and intubated with number 7 size endotracheal tube. As the peak airway pressure went up to 45 cm H2O, we ventilated her with the pressure controlled mode.

Anesthesia was maintained with oxygen, air (FiO2: 0.8), isoflurane and atracurium. Our target SpO2 was at least 90% and an end-tidal carbon dioxide of 35 mmHg.

A live baby was delivered following, which airway pressure decreased to 24 cm H2O. Fentanyl 100 mcg IV was administered.

Her ABG at the end of surgery was: pH −7.335, pCO2 −49.5, pO2 −77.9, bicarbonate −25.6, base excess −0.3, SO2 −91.4 lactate −1.8, PaO2/FiO2 = 97.

A diagnosis of adult respiratory distress syndrome (ARDS) was made. Differential diagnosis includes aspiration pneumonitis, eclampsia, and amniotic fluid embolism; tocolytic induced pulmonary edema, trophoblastic embolism, endometritis, viral/bacterial pneumonia, sepsis, and trauma.[1]

She was shifted back to intensive care unit for elective ventilation. Chest X-ray revealed bilateral chest infiltrates. She was put on pressure control ventilation-volume guaranteed, positive end-expiratory pressure: 5 and FiO2 of 0.5. After 12 h, her PaO2/FiO2 improved to 154. She was put on pressure support ventilation mode with FiO2 of 0.5; her PaO2/FiO2 was 258. She was extubated on the third postoperative day (POD). She was shifted to ward on POD-4. She was discharged on POD-7 with SpO2 of 94% on room air, RR: 22/min, HR: 84/min.

Pregnancy has been a risk factor for increased illness and mortality for pandemic influenza due to shifting away from cell-mediated immunity toward humoral immunity.[2] Preoperative invasive mechanical ventilation was avoided because benzodiazepines and opiates have a high maternal to fetal ratio causing respiratory depression and floppy infant syndrome. Repeated use of neuro-muscular blocking agents poses a risk in the fetus.[3] Maternal ARDS is associated with fetal HR abnormalities, preterm labor, and fetal mortality.

For pregnant H1N1 patients, oseltamivir and paracetamol are useful.[4] Paracetamol is an important adjunct because hyperthermia has been associated with fetal damage during pregnancy including cerebral palsy and neonatal death.[4]

A combination of propofol and ketamine provides hemodynamic stability. Furthermore, ketofol has an anti-inflammatory effect in lung tissue and counters oxidative stress.[5]