Neuro-intensive treatment targeting intracranial hypertension improves outcome in severe bacterial meningitis: an intervention-control study

Abstract

Objective: To evaluate the efficacy of early intracranial pressure (ICP)-targeted treatment, compared to standard intensive care, in adults with community acquired acute bacterial meningitis (ABM) and severely impaired consciousness.

Design: A prospectively designed intervention-control comparison study of adult cases from September 2004 to January 2012.

Patients: Included patients were confirmed ABM-cases, aged 16-75 years, with severely impaired mental status on admission. Fifty-two patients, given ICP-targeted treatment at the neuro-intensive care unit, and 53 control cases, treated with conventional intensive care, were included. All the patients received intensive care with mechanical ventilation, sedation, antibiotics and corticosteroids according to current guidelines. Additional ICP-treatment in the intervention group included cerebrospinal fluid drainage using external ventricular catheters (n = 48), osmotherapy (n = 21), hyperventilation (n = 13), external cooling (n = 9), gram-doses of methylprednisolone (n = 3) and deep barbiturate sedation (n = 2) aiming at ICP <20 mmHg and a cerebral perfusion pressure of >50 mmHg.

Measurements: The primary endpoint was mortality at two months and secondary endpoint was Glasgow outcome score and hearing ability at follow-up at 2-6 months.

Outcomes: The mortality was significantly lower in the intervention group compared to controls, 5/52 (10%) versus 16/53 (30%; relative risk reduction 68%; p<0.05). Furthermore, only 17 patients (32%) in the control group fully recovered compared to 28 (54%) in the intervention group (relative risk reduction 40%; p<0.05).

Conclusions: Early neuro-intensive care using ICP-targeted therapy, mainly cerebrospinal fluid drainage, reduces mortality and improves the overall outcome in adult patients with ABM and severely impaired mental status on admission.

Figure 1. The algorithm for inclusion and exclusion of patients.

Inclusion criteria were: 1) age 16–75 years, 2) severely impaired mental status on admission, and 3) confirmed acute bacterial meningitis (ABM). Patients were initially included in the intervention group based on clinical suspicion of ABM with or without cerebrospinal fluid analysis. SQRM = Swedish National Quality Registry for ABM. ICP = intracranial pressure. NICU = neuro-intensive care unit. ICU = intensive care unit.

Figure 2. The algorithm for treatment of increased intracranial pressure (ICP) in the neuro-intensive care unit (n = 52).

An external ventricular drainage (EVD) was established at operation in 50 patients with initial cerebrospinal fluid (Csf) drainage in 48 of these. A parenchymal ICP-monitor (Codman) was inserted in four cases. Bolus doses of Mannitol were administered in five cases prior to neuro-intervention. The shaded numbers represent different patients.

Figure 3. The highest levels of intracranial pressure (ICP), as observed continuously during episodes of more than 5 min, in the neuro-intensive care unit after initial cerebrospinal fluid drainage at operation; n = 52 (external ventricular drainage; n = 48, parenchymal ICP-monitor; n = 4).