Hemant Bhagat

Planning for early emergence in neurosurgical patients: a randomized prospective trial of low-dose anesthetics.

BACKGROUND: For early detection of a cerebral complication, rapid awakening from anesthesia is essential after craniotomy. Systemic hypertension is a major drawback associated with fast tracking, which may predispose to formation of intracranial hematoma. Although various drugs have been widely evaluated, there are limited data with regards to use of anesthetics to blunt emergence hypertension. We hypothesized that use of low-dose anesthetics during craniotomy closure facilitates early emergence with a decrease in hemodynamic consequences. METHODS: Three emergent techniques were evaluated in 150 normotensive adult patients operated for supratentorial tumors under standard isoflurane anesthesia. At the time of dural closure, the patients were randomized to receive low-dose propofol (3 mg · kg−1 · h−1), fentanyl (1.5 &mgr;g · kg−1 · h−1) or isoflurane (end-tidal concentration of 0.2%) until the beginning of skin closure. Nitrous oxide was discontinued after head dressing. RESULTS: Median time to emergence was 6 min with propofol, 4 min with fentanyl, and 5 min with isoflurane (P = 0.008). More patients had hypertension in the pre-extubation compared with extubation or postextubation phase (P = 0.009). Comparing the three groups, fewer patients required esmolol with fentanyl use overall, and in the pre-extubation phase (P = 0.01). Significant midline shift in the preoperative cerebral imaging scans was found to be an independent risk factor for emergence hypertension. CONCLUSIONS: Pain during surgical closure may be an important cause of sympathetic stimulation leading to emergence hypertension. The use of low-doses of fentanyl during craniotomy closure is more advantageous than propofol or isoflurane for early emergence in neurosurgical patients and is the most effective technique for preventing early postoperative hypertension.

Comparison of Small Dose Ketamine and Dexmedetomidine Infusion for Postoperative Analgesia in Spine Surgery--A Prospective Randomized Double-blind Placebo Controlled Study.

Background: High doses of opioids are frequently used to treat postoperative pain after spine surgery. This leads to opioid-related side effects like nausea, vomiting, respiratory depression, etc. The current study is an attempt to find a safe analgesic adjuvant, which will afford opioid sparing property. Method: Sixty-six patients undergoing spine surgery were randomized into 1 of the 3 groups—group K (ketamine bolus 0.25 mg/kg followed by infusion of 0.25 mg/kg/h with midazolam bolus 10 &mgr;g/kg and infusion of 10 &mgr;g/kg/h mixed in the same infusion pump), group D (dexmedetomidine bolus 0.5 &mgr;g/kg followed by 0.3 &mgr;g/kg/h infusion), and group C (normal saline). Study drugs were started in the postoperative period and continued for 24 hours. Pain-free period, pain scores, rescue analgesic (morphine) requirements, and side effects were noted for 48 hours postoperatively. Result: Mean pain-free periods in the ketamine group (860 min) and the dexmedetomidine group (580 min) were longer than in the saline group (265 min) (P<0.002) during the observation period of 48 hours. There was a significant decrease in the rescue analgesic requirement in both ketamine and dexmedetomidine group (P<0.05) (cumulative morphine requirement at 24 h—group C 15.64±9.31 mg, group D 6.89±5.88 mg, group K 2.45±2.06 mg; at 48 h—group C 21.09±12.88 mg, group D 7.98±7.72 mg, group K 2.59±1.97 mg). Hemodynamics were maintained within normal range in all the groups. Patients in ketamine and dexmedetomidine groups were sedated, but none required assistance for maintaining airway patency. Few patients in the ketamine group had nausea, dizziness, and diplopia, but the difference was insignificant in comparison with other groups (P>0.05). Conclusions: Infusion of low-dose ketamine and dexmedetomidine both provide good postoperative analgesia with minimal side effects. Both of the tested analgesic regimes can be used safely and effectively for postoperative pain relief in patients after spine surgery.

ST elevation - An indication of reversible neurogenic myocardial dysfunction in patients with head injury

This report describes a patient who presented with signs of meningitis four days after head injury. The patient had ST elevation on electrocardiography along with hypotension and positive tropinin T test, mimicking inferior wall infarction. The ST changes resolved within 48 hours of intensive care management. Subsequent investigations failed to document any myocardial infarction.

Hemodynamic and bispectral index changes following skull pin attachment with and without local anesthetic infiltration of the scalp

We studied the hemodynamic and bispectral index (BIS) changes in 44 patients undergoing cervical diskectomy with attachment of a Gardner-Wells tong (with two sharp conical pins) to the skull to facilitate intraoperative bone graft insertion. Patients were induced with fentanyl, thiopentone, and rocuronium and maintained with 66% nitrous oxide and 0.5% isoflurane, Before insertion of the pins, patients were randomly allocated to have either saline or lidocaine infiltration of the scalp at the proposed pin sites. Two minutes later, the pins were driven into the scalp. The BIS, mean arterial pressure (MAP), and heart rate (HR) were recorded before (baseline) and at 30, 60, 90, and 120 s after pin insertion. Data were compared with the baseline values and between the groups. A significant increase in MAP and HR occurred throughout the study period in the saline group. Skull pinning increased BIS throughout the study period in the saline group only, with maximal increases observed at 90 and 120 s (66.1 ± 6.3 at 90 s and 65.7 ± 6.4 at 120 s versus a baseline value of 62 ± 8, P < 0.001). The increase in BIS was significant in the saline group compared with the lidocaine group at each time point. In conclusion, increases in MAP, HR, and BIS produced by skull pinning were prevented by prior local anesthetic infiltration.

Is phenytoin administration safe in a hypothermic child

A male neonate with a Chiari malformation and a leaking myelomeningocoele underwent ventriculoperitoneal shunt insertion followed by repair of myelomeningocoele. During anaesthesia and surgery, he inadvertently became moderately hypothermic. Intravenous phenytoin was administered during the later part of the surgery for seizure prophylaxis. Following phenytoin administration, the patient developed acute severe bradycardia, refractory to atropine and adrenaline. The cardiac depressant actions of phenytoin and hypothermia can be additive. Administration of phenytoin in the presence of hypothermia may lead to an adverse cardiac event in children. As phenytoin is a commonly used drug, clinicians need to be aware of this interaction.

Capnography as an aid in localizing the phrenic nerve in brachial plexus surgery. Technical note

Background To determine whether monitoring end- tidal Carbon Dioxide (capnography) can be used to reliably identify the phrenic nerve during the supraclavicular exploration for brachial plexus injury. Methods Three consecutive patients with traction pan-brachial plexus injuries scheduled for neurotization were evaluated under an anesthetic protocol to allow intraoperative electrophysiology. Muscle relaxants were avoided, anaesthesia was induced with propofol and fentanyl and the airway was secured with an appropriate sized laryngeal mask airway. Routine monitoring included heart rate, noninvasive blood pressure, pulse oximetry and time capnography. The phrenic nerve was identified after blind bipolar electrical stimulation using a handheld bipolar nerve stimulator set at 2–4 mA. The capnographic wave form was observed by the neuroanesthetist and simultaneous diaphragmatic contraction was assessed by the surgical assistant. Both observers were blinded as to when the bipolar stimulating electrode was actually in use. Results In all patients, the capnographic wave form revealed a notch at a stimulating amplitude of about 2–4 mA. This became progressively jagged with increasing current till diaphragmatic contraction could be palpated by the blinded surgical assistant at about 6–7 mA. Conclusion Capnography is a sensitive intraoperative test for localizing the phrenic nerve during the supraclavicular approach to the brachial plexus.

Airway obstruction after extubation following use of transesophageal echocardiography for posterior fossa surgery in the sitting position.

We report respiratory obstruction following surgery in the sitting position with tracheal intubation and placement of a transesophageal echocardiography probe. Obstruction was due to pharyngeal oedema, which resolved with 24 hours. The mechanisms of this complication are discussed.

Use of spontaneous ventilation to monitor the effects of posterior fossa surgery in the sitting position

We describe the successful excision, guided by spontaneous ventilation, of a cervico-medullary hemangioblastoma in a 22-year-old female in the sitting position. A balanced anesthesia technique comprising an oxygen, nitrous oxide, sevoflurane, fentanyl and vecuronium mixture was used. Apart from routine monitors, electroencephalographic spectral entropy monitoring was used to determine the depth of anesthesia and transesophageal echocardiography for detection of venous air embolism. The patient remained in spontaneous ventilation for 235min during tumor excision. The intraoperative and postoperative course were uneventful. The patient recovered without any major neurological deficit.

Evaluation of the Effect of Aneurysmal Clipping on Electrocardiography and Echocardiographic Changes in Patients With Subarachnoid Hemorrhage: A Prospective Observational Study.

Background: Electrocardiographic (ECG) and echocardiographic changes that are subsequent to aneurysmal subarachnoid hemorrhage (a-SAH) are commonly observed with a prevalence varying from 27% to 100% and 13% to 18%, respectively. There are sparse data in the literature about the pattern of ECG and echocardiographic changes in patients with SAH after clipping of the aneurysm. Hence, we observed the effect of aneurysmal clipping on ECG and echocardiographic changes during the first week after surgery, and the impact of these changes on outcome at the end of 1 year. Materials and Methods: This prospective, observational study was conducted in 100 consecutive patients with a-SAH undergoing clipping of ruptured aneurysm. ECG and echocardiographic changes were recorded preoperatively and every day after surgery until 7 days. Outcome was evaluated using the Glasgow outcome scale at the end of 1 year. Results: Of 100 patients, 75 had ECG changes and 17 had echocardiographic changes preoperatively. The ECG changes observed were QTc prolongation, conduction defects, ST-wave and T-wave abnormalities, tachyarrhythmias, and bradyarrhythmias. The echocardiography changes included global hypokinesia and regional wall motion abnormalities. Both echocardiographic and ECG changes showed significant recovery on the first postoperative day. Patients presenting with both echocardiographic and ECG changes were found to require higher ionotropic support to maintain the desired blood pressure, and were associated with poor outcome (Glasgow outcome scale, 1 to 2) at 1 year after surgery. There was no association of ECG and echocardiographic changes with mortality (both in-hospital or at 1 year). Conclusions: The ECG changes, such as QTc prolongation, bradycardia, conduction abnormality, and echocardiographic changes, recover on postoperative day-1, in most of the cases after clipping. Patients with combined ECG and echocardiographic changes tend to have poor neurological outcome at the end of 1 year.

A comparison of 3% saline and mannitol for brain relaxation during elective supratentorial brain tumor surgery.

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