Acute respiratory failure after endoscopic third ventriculostomy: A case report and review of the literature
An 8-month-old infant, weighing 9 kg, a product of uneventful pregnancy and normal delivery presented with enlarging head and sunset appearance of the eyes. His development was within normal but has difficulty in turning due to heavy head. His head circumference was above the 97th percentile, and the anterior fontanele was wide, full and slightly tense. He had upward gaze palsy and the rest of neurological examination was otherwise normal. Radiological investigations showed obstructive hydrocephalus caused by a large posterior fossa arachnoid cyst, distorting and occluding the fourth ventricle outlet; and associated with downward herniation of the cerebellar tonsils through the foramen magnum [].\nHe underwent ETV through the right angle of the anterior fontanelle successfully. On an attempt to fenestrate the posterior fossa cyst through the lateral ventricle, he bled and the procedure had to be abandoned leaving an EVD in the lateral ventricle, which was kept opened at a level of 10-cm height from the patient's head. Anesthesia was induced with 7-8% sevoflurane in oxygen. Ventilation with face mask was found to be easy. Fentanyl 10 microgram (mcg) and Cisatracurium 1 mg were given intravenously (i.v.) to facilitate endotracheal (ET) intubation. First attempt was with 3.5-mm internal diameter noncuffed polyvenyl chloride (PVC) ET tube was not successful as the anesthetist found it to be grade 3 intubation (Cormack and Lehane Classification).[] The second anesthetist inserted the same ET tube after repositioning the shoulder roll resulting in improved glottic view. There was little leak of air around the ET tube on gentle intermittent positive pressure ventilation (IPPV). After intubation, 125 mg paracetamol suppository was inserted. Anesthesia was maintained with 2-3% sevoflurane in 50% oxygen air mixture and patient received an additional bolus of fentanyl in the dose of 5 mcg. Anesthesia course was uneventful except slight drop in body temperature to 34°C despite of the use of fluid and body warmers. After completion of the surgery, the patient was warmed to 36.5°C and inhalational anesthetic terminated. Residual neuromuscular block was reversed with mixture of neostigmine and atropine. Trachea of the patient was extubated when the patient was fully awake after attaining adequate respiration and shifted to postanesthesia care unit (PACU). During first hour of stay in PACU, the patient's vital were stable and no additional analgesic was needed. Before shifting the patient to ward, oxygen face mask was removed to assess breathing on room air, but oxygen saturation by pulse oximeter (SPO2) dropped to 90% and mild inspiratory stridor was noted. There were no signs of respiratory distress at that stage. The SPO2 improved to 98% when oxygen face mask with 5 liters/min flow was applied. The cause of inspiratory stridor was not obvious and intubation trauma secondary to two attempts at intubation was considered to be a possibility. There was no change in the vital signs or in the severity of stridor. It was decided to shift him to the pediatric intensive care unit (PICU) for observation and further management as it was not safe to send this patient to the ward. While waiting for PICU admission, the patient received 2.5 mg dexamethasone was given i.v. followed by 2.25% racemic epinephrine nebulization in the dose of 0.25 ml in 3-ml normal saline. It resulted in rise in heart rate from 125 to 150 beats/min; however, other vital signs were unchanged during this period. After 45 minutes of nebulization the patient rapidly developed difficulty in breathing and SPO2 dropped to 80%, which improved to 95% when IPPV and PEEP were applied through anesthesia face mask attached to Ayre's T-piece circuit connected with 100% oxygen with 8 liters/min flow. The trachea of the patient was reintubated with same size ET tube after administering 10 mcg fentanyl i.v. After ET intubation, the patient developed generalized tonic-clonic seizure, which was controlled with 0.5 mg Midazolam i.v. Another episode of seizure recurred after 10 minutes and controlled with an additional dose of 1 mg midazolam i.v. An emergency CT scan was done which showed marginally smaller lateral ventricles with extra-axial fluid collection, and crowded foramen magnum. There was some blood in the occipital horns and tip of the EVD was in the lateral ventricle []. The patient was then shifted to PICU and connected to mechanical ventilation.\nHe maintained his vital signs and was stable enough next morning to arrange an MRI scan, which revealed reduction in the size of the ventricles, wide supratentorial subdural space, along with marginal increase in the posterior fossa cyst and anterior displacement and compression of the brain stem against the clivus. The brain stem was kinked and compressed, and the foramen magnum was crowded by the cerebellar tonsils compromising the medulla [].\nHe was taken back to theater for craniocervical decompression; suboccipital craniectomy and removal of the posterior arch of Atlas, followed by durotomy and Gor-tex duroplasty, and insertion of cystoperitoneal shunt. Postoperatively, he recovered and his breathing improved dramatically that he could be weaned successfully off the ventilator and discharged of the hospital in a week's time.\nHe was seen in the outpatient clinic after 1 month, his parents reported improvement in his behavior and motor development, they also noticed slight reduction in the head size. A CT scan at that time showed stable ventricular size and subdural space, while posterior fossa cyst size was marginally smaller [].