Nitin Manohar

A comparative study of midazolam and target-controlled propofol infusion in the treatment of refractory status epilepticus

Background: The recommended treatment for refractory status epilepticus (RSE) is the use of anesthetic agents, but evidence regarding the agent of choice is lacking. This study was designed to compare target-controlled infusion of propofol versus midazolam for the treatment of RSE regarding seizure control and complications. Methods: This prospective, randomized study recruited 23 adult patients with RSE due to any etiology and treated with either propofol or midazolam titrated to clinical seizure cessation and gradual tapering thereafter. The primary outcome measure was seizure control and the secondary outcomes were duration of the Intensive Care Unit stay and duration of mechanical ventilation, occurrence of super RSE (SRSE), and complications. Results: We recruited 23 patients (male:female = 18:5) into this study (propofol Group-11; midazolam Group-12). Overall, seizure control was noted in 34.8%, with successful seizure control in 45% of patients in the propofol group and 25% in midazolam group (P = 0.4). Mortality was similar in both the groups (propofol group [8/11; 72.7%] compared to the midazolam group [7/12; 58.3%] [P = 0.667]). The duration of hospital stay was significantly shorter in the propofol group compared to midazolam (P = 0.02). The overall incidence of SRSE was 69.5% in this study. The complication rate was not significantly different between the groups. Conclusions: The choice of anesthetic agent does not seem to affect the overall outcome in RSE and SRSE. Target-controlled propofol infusion was found to be equal in its efficacy to midazolam for the treatment of RSE. High mortality might be due to SRSE secondary to the underlying brain pathology.

Brainstem Contusion: A Fallacy of GCS-BIS Synchrony.

To JNA Readers: The correlation between the Glasgow Coma Scale (GCS) and the Bispectral Index (BIS) in traumatic brain injury patients has been demonstrated in multiple studies. The BIS score has also been shown to be a predictor of the outcome in this group of patients. However, the BIS value is only representative of the cortical activity of the frontal lobe over which the electrode has been placed. We present here a case of traumatic acute subdural hematoma (SDH) with midbrain contusion and poor GCS, but apparently normal cortical electrical activity as evidenced by BIS monitoring. The case was of a 46-year-old male patient with traumatic right fronto-temporo-parietal acute SDH (volumeE45mL, midline shift 8.9mm on noncontrast computed tomographic [CT] scan, approximately 9h after the injury). The patient’s admission GCS was E1V1M2, and the decision was made for emergent evacuation of SDH. The BIS electrode was placed before induction on the opposite side as described by Nelson et al3 to prevent intraoperative disruption of readings due to blood soakage. Unexpectedly, the baseline BIS of the patient was 92, with a spectral edge frequency of 25Hz. We had expected a lower BIS value due to the low GCS score. Induction of anesthesia was performed with injection thiopentone and maintained with sevoflurane with a target BIS between 40 and 60. About 0.7 to 0.8MAC of sevoflurane was required for maintenance. The intraoperative course was uneventful. Postoperative anesthetic withdrawal led to an increase in the BIS to preoperative levels, and the GCS was status quo. Because of a discrepancy between the BIS values and the GCS, the EEG waveform obtained from the BIS monitor was evaluated during and after the surgery, but spikes suggestive of seizure activity (which may artifactually elevate the BIS value) were not noted. The patient maintained a normal pattern of spontaneous respiration and hemodynamics in the postoperative period. The CT scan was reviewed again, and specks of hemorrhage were noted on the posterolateral aspect of the midbrain bilaterally with adjacent parenchymal hypodensity (Fig. 1A). Brainstem contusion was thus surmized as the cause of low GCS in a patient with apparently intact cortical electrical activity. The postoperative day 1 CT scan showed the contusions on the midbrain more clearly (Fig. 1B). Multiple applications of BIS since its introduction have the common theme of analyzing the superficial cortical neuronal activity. The apparent correlation of BIS and GCS in traumatic brain injury is based on the premise of fronto-temporal neuronal dysfunction. Our case illustrates that it is possible for a patient to have apparently normal cortical neuronal activity and a decreased level of consciousness due to damage to subcortical structures. On scrutinizing the CT scan, the brainstem injury was localized to the tegmentum, which houses the reticular formation and the red nucleus, damage to which may result in the impairment of consciousness and decerebrate posturing. A study by Paul et al1 on 29 mild to moderate head injury patients revealed a strong positive correlation between BIS values and GCS (r=0.67; P<0.001). However, they noted that the excessive scatter of the BIS values prevented the prediction of GCS from a single BIS value. In our experience, on the basis of unpublished data, we noted that headinjured patients with low GCS scores tend to have low baseline BIS values FIGURE 1. A, The preoperative computed tomographic (CT) scan showing specks of hemorrhage on the midbrain surface (black arrows). B, The postoperative day 1 CT scan shows well-defined midbrain contusions (white arrows).