ABSTRACT
Recently, we showed the feasibility of ventilating neurosurgical patients with acute intracranial pathology and concomitant acute respiratory distress syndrome (ARDS) according the so-called Open Lung approach. This technique consists of low tidal volume, elevated positive expiratory pressure (PEEP) level and initial recruitment maneuvers to open up collapsed alveoli. In this report, we focus on our experience to guide recruitment with brain tissue oxygenation (pbrO2) probes. We studied recruitment maneuvers in thirteen patients with ARDS and acute brain injury such as subarachnoid hemorrhage and traumatic brain injury. A pbrO2 probe was implanted in brain tissue at risk for hypoxia. Recruitment maneuvers were performed at an inspired oxygen frcation (FiO2) of 1.0 and a PEEP level of 30 40 cmH2O for 40 seconds. The mean FiO2 necessary for normoxemia could be decreased from 0.85 +/- 0.17 before recruitment to 0.55 +/- 0.12 after 24 hours, while mean PbrO2 (24.6 mmHg before recruitment) did not change. At a mean of 17 minutes after the first recruitment maneuver, PbrO2 showed peak a value of 35.6 +/- 16.6 mmHg, reflecting improvement in arterial oxygenation at an FiO2 of 1.0. Brain tissue oxygenation monitoring provides a useful adjunct to estimate the effects of recruitment maneuvers and ventilator settings in neurosurgical patients with acute lung injury.
Subject(s)
Brain Injuries/diagnosis , Brain Injuries/surgery , Brain/metabolism , Intracranial Pressure , Monitoring, Physiologic/methods , Oxygen/metabolism , Positive-Pressure Respiration/methods , Respiratory Distress Syndrome/diagnosis , Acute Disease , Brain Injuries/complications , Brain Injuries/metabolism , Humans , Neurosurgery/methods , Oxygen/analysis , Preoperative Care/methods , Respiratory Distress Syndrome/metabolism , Respiratory Distress Syndrome/surgery , Treatment OutcomeABSTRACT
OBJECTIVE: The predisposing factors for the development of posthemorrhagic hydrocephalus, requiring shunt implantation, after subarachnoid hemorrhage (SAH) are still not exactly known. Therefore we analyzed the patients with SAH, who were treated in our department with respect to the development of chronical cerebro-spinal fluid (CSF) imbalance, trying to define predictive parameters for this entity. METHODS: All patients presenting with SAH were analyzed retrospectively between September 1992 and July 1998. Special consideration was given to the initial CT scan (cistern index, Fisher grade, bicaudate index) and the requirement for an external ventricular drainage. Other possible predictive factors as age, Hunt & Hess grade, electrolyte disturbances and operative techniques were also evaluated. RESULTS: During the investigation period, 283 patients presenting with aneurysmal SAH underwent surgery. Fifty-two patients (18.4%) required a shunting procedure due to chronic posthemorrhagic hydrocephalus. The mean time interval between the initial bleeding and shunting was 28 days. All of these patients required a significantly longer external CSF drainage (p < 0.001) with a much higher amount of daily drained CSF (p < 0.001). The evaluation of the initial CT scan revealed no correlation between the amount of blood and later shunt dependency. However, there was a significant correlation with the bicaudate index (p < 0.01). CONCLUSION: Chronic hydrocephalus after aneurysmal SAH is an important complication. The recovery-time of shunt dependent patients is definitely prolonged compared to non-shunted patients. Predictive factors of shunt dependency seem to be length and amount of the external CSF drainage, as well as a high bicaudate index.
