A 53-year-old hypertensive woman (actual body weight, 70 kg; height, 160 cm) was admitted to the hospital with coma (Glasgow Coma Scale E1+M3+V1t) after acute onset ictal headache. Computed tomography (CT) of the head showed subarachnoid hemorrhage with severe intraventricular extension and right temporal intraparenchymal hematoma (Figure 43-1). Cerebral angiography demonstrated 2 aneurysms of the carotid siphon, at the origin of posterior communicating arteries, bilaterally, with likely bleeding from the right one (9 mm diameter, neck 3.5 mm). An external ventricular drain was placed, the blood pressure was controlled with nicardipine drip, and the patient underwent endovascular coiling of the right carotid artery aneurysm.
Computed tomographic (CT) scan of the head on admission showing subarachnoid hemorrhage with severe intraventricular extension.
On ICU admission, after coiling, her pupils were equal and reactive to light. Sedation was maintained with infusions of propofol, 30 to 60 µg/kg/min, and remifentanyl, 0.5 to 1 μg/kg/min. The patient, whose predicted body weight (PBW) was 52.2 kg, was ventilated by pressure-limited, volume-cycled ventilation with a tidal volume of ≈8 mL/kg per PBW, respiratory rate of 20 breaths per min, positive end-expiratory pressure (PEEP) of 8 cm H2O and Fio2 of 0.4. Arterial gas analysis revealed pH 7.42, Po2 164 mm Hg, Pco2 41 mm Hg, HCO3− 27 mmol/L, base excess 3.2 mmol/L, lactate 1.3 mmol/L, Po2/Fio2 ratio (P/F) 410. Her hemodynamic profile was characterized by hypertension, which was tolerated following the aneurysm coiling procedure. Intracranial pressure (ICP) remained within normal values, neurologic examination revealed GCS E3+M4+V1T. Enteral nimodipine, 60 mg q4h, was administered Fio2
On day 6, the clinical course was complicated by fever, presence of abundant pulmonary secretions and a decrease of the P/F ratio to 170. Chest radiograph showed a right basilar infiltrate (Figure 43-2). Empiric antibiotic therapy for nosocomial, ventilator-associated pneumonia was started with linezolid, 600 mg IV q12h, and piperacillin-tazobactam, 4.5 g IV q8h.
Chest radiograph on day 6 showing a focal right lower lobe infiltrate.
On day 8, CT angiography of the head revealed moderate vasospasm in the territory of right anterior and middle cerebral arteries, confirmed by cerebral angiography and treated with intraarterial nicardipine. On day 10 tracheostomy was performed. On day 11, she developed severe hypoxemia and met criteria for ARDS according to the Berlin Definition,1 (the P/F ratio dropped to 140 and then to 80), pH 7.45, Pco2 35 mm Hg, Po2 56 mm Hg, HCO3− 24.8 mmol/L, base excess 0.6 mmol/L, lactate 1.4 mmol/L; chest radiograph revealed diffuse and bilateral opacities involving 3 quadrants (Figure 43-3...