Comparative evaluation of intraoperative use of normal saline, Ringer's lactate, and combination of normal saline and Ringer's lactate in neurosurgical patients - A preliminary randomized clinical trial.

BACKGROUND: Fluid management during intracranial surgery is an important concern. The type of fluid used can have biochemical and metabolic effects during intraoperative management. However, it is yet to be known whether biochemical and metabolic effects have an influence on the clinical outcome of a patient. OBJECTIVE: A prospective evaluation of the effects of normal saline (NS), Ringer's lactate (RL), and a combination of NS and RL on the biochemical, metabolic, and clinical outcomes in patients undergoing intracranial tumor surgery was carried out. MATERIALS AND METHODS: Ninety patients undergoing elective intracranial tumor surgery were randomized to receive NS, RL, or a combination of NS and RL. The biochemical and metabolic parameters were studied at different time points in the intraoperative and postoperative period. The hemodynamic parameters, brain relaxation score at the time of bone flap elevation, postoperative complications, and the duration of hospital stay were the clinical outcome variables of our study. RESULTS: The use of NS was associated with hyperchloremic metabolic acidosis and ionic hypocalcemia. RL caused significant hyponatremia and increase in serum lactate levels. The combination of NS and RL has least influence on biochemical and metabolic parameters. The effects of three fluids were similar on the hemodynamics, brain relaxation score, as well as on postoperative complications and the duration of postoperative hospital stay. CONCLUSION: There are variable effects of NS, RL, or its combination on the biochemical and metabolic parameters in patients undergoing intracranial tumor surgery. However, the clinical outcome of the patients remains similar.

Post-operative pulmonary complications in patients undergoing transoral odontoidectomy and posterior fixation for craniovertebral junction anomalies.

BACKGROUND: In patients with craniovertebral junction (CVJ) anomalies, the respiratory system is adversely affected in many ways. The sub-clinical manifestations may get aggravated in the postoperative period owing to anesthetic or surgical reasons. However, there is limited data on the incidence of postoperative pulmonary complications (PPCs) and associated risk factors in such patients, who undergo transoral odontoidectomy (TOO) and posterior fixation (PF) in the same sitting. MATERIALS AND METHODS: Five years data of 178 patients with CVJ anomaly who underwent TOO and PF in the same sitting were analyzed retrospectively. Preoperative status, intraoperative variables, and PPCs were recorded. Patients were divided into two groups depending on the presence or absence of PPCs. Bivariate analysis was done to find out association between various risk factors and PPCs. Multivariate analysis was done to detect relative contribution of the factors shown to be significant in bivariate analysis. P < 0.05 was considered as significant. RESULTS: The incidence of PPCs was found to be 15.7%. Factors significantly associated with PPCs were American Society of Anesthesiologists grade higher than II, preoperative lower cranial nerves palsy and respiratory involvement, duration of surgery, and intraoperative blood transfusion. In multivariate analysis, blood transfusion was found to be the sole contributing factor. The patients who developed PPCs had significantly prolonged stay in ICU and hospital. CONCLUSION: Patients with CVJ anomaly are at increased risk of developing PPCs. There is a strong association between intraoperative blood transfusion and PPCs. Patients with PPCs stay in the ICU and hospital for a longer period of time.

Effect of intraoperative dexmedetomidine on postoperative recovery profile of children undergoing surgery for spinal dysraphism.

BACKGROUND: Smooth recovery from anesthesia is desirable in children undergoing surgery for spinal dysraphism who are nursed in prone position during the postoperative period. Dexmedetomidine may be beneficial in these children owing to its sedative, anxiolytic, and opioid-sparing properties with minimal respiratory depression. METHODS: Thirty-six children with spinal dysraphism at lumbosacral area, aged 8 to 12 years, undergoing corrective surgery were randomized to receive either dexmedetomidine or volume-matched saline (placebo) after positioned prone until beginning of skin closure. Inspired concentration of sevoflurane was changed to keep the bispectral index score between 45 and 55. Perioperative hemodynamics, intraoperative fentanyl and sevoflurane consumption, and postoperative recovery profile and fentanyl consumption was observed by blinded observers. Postoperative pain, emergence agitation (EA), and discharge readiness from postanesthesia care unit was evaluated using the modified objective pain score, agitation Cole score, and modified Aldrete score, respectively. Fentanyl 0.5-1 µg/kg was administered for pain (objective pain score ≥4) or severe EA (agitation Cole score ≥4) lasting for >5 minutes. RESULTS: The 2 groups did not differ significantly with respect to demographics, duration of anesthesia, emergence, and extubation times. The intraoperative consumption of sevoflurane and fentanyl was significantly less in dexmedetomidine group (0.2±0.1 vs. 0.3±0.1 mL/min, P<0.0001 and 2.3±0.5 vs. 3.1±0.6 µg/kg, P=0.0001, respectively), along with a lower mean heart rate (P<0.001). The mean systolic blood pressure (P=0.98) and incidence of bradycardia and hypotension was comparable in between the 2 groups. Postoperatively, the children in dexmedetomidine group had significantly lower pain scores (P<0.0001), agitation scores (P<0.0001), and time to achieve full modified Aldrete score [0 (0 to 10) vs. 10 (0 to 20) min, P=0.001]. The postoperative consumption of fentanyl was significantly less in dexmedetomidine group [0 (0 to 1.04) vs. 0.88 (0 to 3) µg/kg, P=0.003], along with a longer time of first analgesic requirement [600 (5 to 2100) vs. 5 (5 to 185) min, P=0.0001]. The mean heart rate and systolic blood pressure were higher in placebo group (P<0.001), whereas no difference was observed in respiratory rate (P=0.73) and arterial oxygen saturation (P=0.36). The number of patients with postoperative nausea and vomiting was significantly lower in dexmedetomidine group [2 (11.1%) vs. 9 (50%), P=0.03]. CONCLUSIONS: Intraoperative use of dexmedetomidine in children undergoing spinal surgery results in a favorable recovery profile with reduced postoperative pain and EA, without adverse perioperative hemodynamic effects.

Comparative evaluation of percutaneous retrogasserian glycerol rhizolysis and radiofrequency thermocoagulation techniques in the management of trigeminal neuralgia.

BACKGROUND: Among the percutaneous procedures for the treatment of trigeminal neuralgia, percutaneous anhydrous glycerol rhizolysis (PRGR) and radiofrequency (RF) ablation of trigeminal neuralgia have stood the test of time. OBJECTIVE: A prospective study was conducted to compare PRGR and RF ablation techniques in patients with trigeminal neuralgia in terms of (1) efficacy of pain relief, (2) duration of pain relief and (3) side effects. METHODS: All patients presenting to our pain clinic for the first time for the treatment of trigeminal neuralgia were enrolled to receive either PRGR or RF ablation; the treatment was chosen by the patient. Demographic data, magnetic resonance imaging scan, relevant medical disease, amount of anhydrous glycerol, lesion temperature, and total duration of RF were noted. The presence or absence of cerebrospinal fluid egress, immediate pain relief, duration of pain-free period, need for repeat injection or additional peripheral nerve block, and recurrence of pain were also noted. The degree of pain relief was recorded every 3 months. Any complications during the procedure and side effects were also recorded. RESULTS: Seventy-nine patients underwent either PRGR (n = 40) or RF thermocoagulation (n = 39). A total of 23 patients (58.9%) in the PRGR group and 33 patients (84.6%) in the RF group experienced excellent pain relief. The mean duration of excellent pain relief in the PRGR and RF groups was comparable. By the end of the study period, 39.1% patients in the PRGR group and 51.5% patients in the RF group experienced recurrence of pain. CONCLUSION: Both PRGR and RF techniques can achieve acceptable pain relief with minimal side effects.

A comparative evaluation of nitrous oxide-isoflurane vs isoflurane anesthesia in patients undergoing craniotomy for supratentorial tumors: A preliminary study.

BACKGROUND: Neuroanesthesiologists are a highly biased group; so far the use of nitrous oxide in their patient population is concerned. We hypothesized that any adverse consequence with use of nitrous oxide should affect the patient so as to prolong his/her stay in the hospital. The primary aim of this preliminary trial was to evaluate if avoidance of nitrous oxide could decrease the duration of Intensive Care Unit (ICU) and hospital stay after elective surgery for supratentorial tumors. PATIENTS AND METHODS: A total of 116 consecutive patients posted for elective craniotomy for various supratentorial tumors were enrolled between April 2008 and November 2009. Patients were randomly divided into Group I: Nitrous oxide - Isoflurane anesthesia (Nitrous oxide-based group) and Group II - Isoflurane anesthesia (Nitrous oxide-free group). Standard anesthesia protocol was followed for all the patients. Patients were assessed till discharge from hospital. RESULTS: The median duration of ICU stay in the nitrous group and the nitrous-free group was 1 (1 - 11 days) day and 1 (1 - 3 days) day respectively (P = 0.67), whereas the mean duration of hospital stay in the nitrous group was 4 (2 - 16) days and the nitrous free group was 3 (2 - 9) days (P = 0.06). The postoperative complications in the two groups were comparable. CONCLUSION: From this preliminary study with a low statistical power, it appears that avoidance of nitrous oxide in one's practice may not affect the outcome in the neurosurgical patients. Further large systemic trials are needed to address this issue.

Cerebral autoregulation and CO2 reactivity before and after elective supratentorial tumor resection.

BACKGROUND: The effect of surgical decompression of tumor on autoregulation and CO2 reactivity is not known. We examined the effect of elective tumor resection on cerebral autoregulation and CO2 reactivity. METHODS: Patients with supratentorial tumors undergoing elective craniotomy for tumor resection under standard anesthesia underwent cerebral autoregulation and CO2 reactivity testing immediately before and between 6 and 24 hours after surgery. Transient hyperemic response of the middle cerebral artery after the release of 10 second compression of the ipsilateral common carotid artery was used to calculate the transient hyperemic response ratio (THRR). THRR>1.1 defined the normal autoregulation. Voluntary hyperventilation was titrated to reduce the ETCO2 by 10 mm Hg below baseline and CO2 reactivity was calculated. RESULTS: Thirty-five patients (26 male and 9 female) were studied. Overall, cerebral autoregulation was intact before and after tumor resection for the cohort (THRR 1.27+/-0.10 and 1.30+/-0.12, P=0.11). However, cerebral autoregulation was impaired preoperatively in 7 (20%) patients and remained impaired in all 7 patients after tumor resection. Larger tumor size (P=0.002), and midline shift more than 5 mm (P<0.001) were associated with impaired cerebral autoregulation. Twenty-eight (80%) patients who had intact preoperative cerebral autoregulation maintained autoregulation postoperatively. CO2 reactivity was within normal limits before and after surgery in all patients and did not change between the 2 periods (3.41+/-0.46/mm Hg and 3.60+/-0.63%/mm Hg, P=0.07). CONCLUSION: Preoperative cerebral autoregulation was impaired in a significant number of patients with large supratentorial tumor size and midline shift more than 5 mm and was associated with postoperative impaired cerebral autoregulation during the first 24 hours after the surgery.

Predicting difficult laryngoscopy in acromegaly: a comparison of upper lip bite test with modified Mallampati classification.

Upper lip bite test (ULBT) is a simple test for predicting difficult intubation. However, it has not been evaluated in acromegalic patients. The primary aim of this study was to compare ULBT with modified Mallampati classification (MMPC) to predict difficult laryngoscopy in acromegalic patients. Over a 5-year period, 64 acromegalic and 63 nonacromegalic patients presenting for excision of pituitary tumor were enrolled. Preoperative airway assessment was done using MMPC and the ULBT. Under anesthesia, laryngoscopic view was assessed using Cormack-Lehane (CL) grading. MMPC III/IV and ULBT grade III were considered predictive of difficult laryngoscopy that was defined as Cormack-Lehane grades III or IV. Difficult intubation was defined as more than 2 direct laryngoscopy attempts involving change of blade or use of bougie/fiberoptic bronchoscope/intubating laryngeal mask airway. Sensitivity, specificity, positive and negative predictive values, and accuracy of both tests in predicting difficult laryngoscopy were calculated. Incidence of difficult laryngoscopy and intubation in acromegalics were 24% and 11%, respectively. MMPC and ULBT predicted difficulty in 61% and 14% acromegalics, respectively. However, only 26% and 44% of the laryngoscopies predicted to be difficult by MMMC and ULBT, respectively, were actually difficult. MMPC failed to predict 33% of difficult laryngoscopies whereas ULBT failed to predict 73%. Neither test predicted difficulty in 33% laryngoscopies that turned out to be difficult. Twenty-seven percent of the difficult laryngoscopies were correctly predicted by both tests. In acromegalic group, MMPC was more sensitive, whereas ULBT was more specific. Sensitivity and accuracy of both tests were less in acromegalic patients compared with nonacromegalic controls.

A review of perioperative complications during frameless stereotactic surgery: our institutional experience.

PURPOSE: Frameless stereotactic neurosurgery is increasingly being used for the biopsy of intracranial tumors and the resection of deep-seated lesions where reliance on surface anatomic landmarks can be misleading, as well as in movement disorders, psychiatric disorders, seizure disorders, and chronic refractory pain. Nascent biological approaches, including gene therapy and stem-cell and tissue transplants for movement disorders, also utilize neuronavigational techniques. These procedures are complex and involve understanding of the basic principles and factors affecting neuronavigation. The procedure may appear to be simple, but serious complications may occur. METHODS: The purpose of this study was to review the intraoperative and postoperative complications occurring during frameless stereotaxy at our institution from January 2003 to July 2007. RESULTS: Seventy-eight patients underwent various neurosurgical procedures under general anesthesia. Intraoperative complications seen were intraoperative brain bulge (n = 3), seizures (n = 3), failure to extubate (n = 4), and fresh neurodeficits (n = 6). No hemodynamic disturbances such as hypertension or hypotension or bradycardia or tachycardia requiring active intervention were observed. CONCLUSION: Awareness and vigilance can help in the early identification and better management of the above intraoperative complications.

Sevoflurane provides better recovery as compared with isoflurane in children undergoing spinal surgery.

Rapid recovery is desirable in pediatric neurosurgical patients to obtain an early neurologic assessment. We compared the recovery characteristics of 2 commonly used anesthetic agents, sevoflurane and isoflurane, under bispectral index-guided anesthesia in children undergoing spinal surgery. Eighty children who underwent surgery for occult spinal dysraphism at the lumbar and sacral level were randomized to anesthesia with sevoflurane or isoflurane in oxygen and nitrous oxide. Anesthesia depth was guided by a bispectral index monitor kept between 40 and 60. In addition to time at emergence, extubation and discharge, recovery (modified Aldrete) score, and hemodynamics were compared. The 2 groups did not differ significantly with respect to demographics, duration of surgery and anesthesia, and intraoperative hemodynamic changes. Extubation (6.4+/-3.3 vs. 10.7+/-4.6) and emergence (7.8+/-3.4 vs. 12.8+/-5.6) times (minutes) were significantly shorter with sevoflurane (P<0.001). Time (minutes) to achieve full Aldrete (modified) scores was less with sevoflurane (13.9+/-5.3 vs. 20.3+/-6.5) than isoflurane (P<0.001). However, the time (minutes) to achieve discharge criteria from postanesthesia care unit (140.7+/-49.3 vs. 146+/-43.3) and first dose of postoperative analgesic (60+/-24.1 vs. 72+/-33.4) in addition to incidence of postoperative agitation were similar in both groups (P>0.05). Sevoflurane results in an earlier recovery and assessment of modified Aldrete score when compared with isoflurane.

A randomized, double-blinded comparison of ondansetron, granisetron, and placebo for prevention of postoperative nausea and vomiting after supratentorial craniotomy.

Postoperative nausea and vomiting (PONV) are frequent and distressing complications after neurosurgical procedures. We evaluated the efficacy of ondansetron and granisetron to prevent PONV after supratentorial craniotomy. In a randomized double-blind, placebo controlled trial, 90 adult American Society of Anesthesiologists I, II patients were included in the study. A standard anesthesia technique was followed. Patients were divided into 3 groups to receive either placebo (saline), ondansetron 4 mg, or granisetron 1 mg intravenously at the time of dural closure. After extubation, episodes of nausea and vomiting were noted for 24 hours postoperatively. Statistical analysis was performed using chi2 test and 1-way analysis of variance. Demographic data, duration of surgery, intraoperative fluids and analgesic requirement, and postoperative pain (visual analog scale) scores were comparable in all 3 groups. It was observed that the incidence of vomiting in 24 hours, severe emetic episodes, and requirement of rescue antiemetics were less in ondansetron and granisetron groups as compared with placebo (P<0.001). Both the study drugs had comparable effect on vomiting. However, the incidence of nausea was comparable in all 3 groups (P=0.46). A favorable influence on the patient satisfaction scores, and number needed to prevent emesis was seen in the 2 drug groups. No significant correlation was found between neurosurgical factors (presence of midline shift, mass effect, pathologic diagnosis of tumor, site of tumor) and the occurrence of PONV. We conclude that ondansetron 4 mg and granisetron 1 mg are comparably effective at preventing emesis after supratentorial craniotomy. However, neither drugs prevented nausea effectively.

EEG entropy values during isoflurane, sevoflurane and halothane anesthesia with and without nitrous oxide.

We hypothesized that like bispectral index, entropy may be anesthetic agent specific. We carried out a study to assess the entropy values of different anesthetics at equi-minimal alveolar concentrations (MACs) with air and nitrous oxide as carrier gases. Thirty adult patients undergoing spine surgery were randomized to receive halothane, isoflurane, or sevoflurane, in 2 stages, (a) with air/oxygen mixture (2:1) and (b) in nitrous oxide/oxygen (2:1). Heart rate, mean arterial blood pressure, response entropy (RE), and state entropy (SE) were noted at 1.0 and 1.5 MACs for each agent. Statistical analysis was done using the 2-way analysis of variance followed by Bonferroni correction and Student t test for paired data. P value of less than 0.05 were considered significant. The demographics and baseline values of heart rate, mean arterial blood pressure, RE, and SE were comparable. Changing from air/oxygen as carrier gas to 66% nitrous oxide in oxygen resulted in significant increase in both RE and SE at 1.0 MAC for all the agents (P<0.05). Among the agents, it was found that both RE and SE values were significantly higher during halothane anesthesia as compared with sevoflurane and isoflurane (P<0.05). At 1.5 MAC for all agents, after addition of nitrous oxide, there was an insignificant reduction in both RE and SE (P>0.05). Again the values of RE and SE remained high for halothane as compared with isoflurane and sevoflurane. In conclusion, our data suggest a possibility of misinterpretation of anesthetic hypnosis when entropy values increase with addition of nitrous oxide to 1 MAC isoflurane and sevoflurane.

Isoflurane and sevoflurane decrease entropy indices more than halothane at equal MAC values.

Recently, bispectral index (BIS) values were demonstrated to be different for various anesthetics as a result of differential effects on electroencephalographic (EEG) signals. Entropy is similar to the BIS monitor, as both process raw EEG to derive a number. We hypothesized that entropy may also be anesthetic agent-specific. Thirty adult patients undergoing spinal surgery were randomized to receive halothane, isoflurane, or sevoflurane. Entropy indices were recorded at various minimum alveolar concentration (MAC) values-0.5, 0.75, 1.0 and 1.5-both during wash-in and wash-out of the agent. Heart rate (HR), mean arterial blood pressure (MAP), response entropy (RE), and state entropy (SE) were noted. Statistical analysis was done using a one-way analysis-ofvariance test. P values less than 0.05 were considered significant. Ten patients in each group completed the study. The demographics and baseline values of HR, MAP, RE, and SE were comparable in all three groups. During the study period, for a given MAC value, both RE and SE remained low in the isoflurane and sevoflurane groups compared to the halothane group. For a given MAC, the RE and SE were comparable during wash-in and wash-out phases. Halothane produced higher entropy values as compared to isoflurane and sevoflurane at equivalent MAC levels.

Bispectral index-guided administration of anesthesia for transsphenoidal resection of pituitary tumors: a comparison of 3 anesthetic techniques.

The main aims of anesthesia for pituitary surgery include maintenance of hemodynamic stability, provision of conditions that facilitate surgical exposure, and a smooth emergence to facilitate a prompt neurologic assessment. The primary aim of our study was to compare the effects of 3 anesthetic regimens on hemodynamics and recovery characteristics of the patients. Ninety patients undergoing transsphenoidal surgery were enrolled in the study. Standard anesthesia technique was followed for induction. Patients were randomly divided to receive propofol, isoflurane, or sevoflurane for maintenance of anesthesia. The bispectral index target range during maintenance was 40 to 60. The hemodynamic variables (heart rate and mean arterial pressure) and bispectral index were noted during the various stages of the surgery. The time to emergence and extubation was noted. We evaluated cognitive function at 5 and 10 minutes posttracheal extubation. The 3 study groups were comparable with respect to age, sex, weight, and duration of surgery. We observed an increase in heart rate and blood pressure during intubation, nasal packing, and insertion of self-retaining nasal speculum. After tracheal intubation, the rise in blood pressure was more in sevoflurane group than propofol. During emergence, hypertensive response was seen in all patients. Emergence and extubation times were significantly shorter with propofol and sevoflurane. Patients who received propofol had better cognition scores. Aldrete scores were better with propofol and sevoflurane than isoflurane. The pressor response after intubation and emergence hypertension was significantly less with propofol. Better recovery profile was seen in sevoflurane and propofol groups and a better cognition in patients receiving propofol. Propofol plus nitrous oxide anesthesia could be the technique of choice in patients undergoing transnasal transsphenoidal pituitary surgery.

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 microg.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.

Effects of butorphanol and fentanyl on cerebral pressures and cardiovascular hemodynamics during tunneling phase for ventriculoperitoneal shunt insertion.

PURPOSE: Subcutaneous tunneling for ventriculoperitoneal shunt insertion is the most painful step of this surgery. It is associated with intense hemodynamic response, may influence the intracranial pressure, and thus may worsen the existing intracranial pathology. The purpose of this report is to evaluate the commonly used opioid fentanyl, along with butorphanol, an agonist-antagonist compound. METHODS: Twenty adult patients undergoing ventriculoperitoneal shunt surgery were induced with fentanyl 2-mcg.kg(-1) and thiopentone 4-5 mg.kg(-1). Intubation followed the administration of rocuronium 1 mg.kg(-1). All patients were put on mechanical ventilation to maintain end-tidal carbon dioxide levels of 32 +/- 2 mmHg. Anesthesia was maintained with isoflurane in N2O and O2 (MAC 1.0 +/- 0.2). Routine monitoring, arterial blood pressure and intracranial pressures were measured. Three minutes prior to the tunneling phase, patients received either fentanyl 1 mcg.kg(-1) or butorphanol 1 mg in a randomized manner. Thereafter hemodynamic and intracranial pressure changes were noted during tunneling and each minute in the post-tunneling period for 5 minutes. The duration of the tunneling phase was also noted. Data were presented as number (proportion) or mean +/- SD/median (range) as appropriate. Statistical analysis was done using Wilkoxon ranksum test and the repeated measures of ANOVA. The value of p < 0.05 was considered significant. RESULTS: A significant rise in the intracranial pressure and cerebral perfusion pressure along with the hemodynamic parameters was noted during the tunneling phase in both groups. The changes were of longer clinical duration in the butorphanol group. CONCLUSION: Butorphanol must be used with caution in neurosurgical patients. The ventricular end of the shunt catheter should preferably be put before the tunneling phase to avoid rise in intracranial pressure.

Rupture of intracranial aneurysm after partial clipping due to aspiration drainage system--a case report.

In neurosurgical practice, extradural or subgaleal drains are commonly placed and connected to a vacuum system. Several reports have described severe bradycardia or arterial hypotension, or both, after connection of negative suction pressure to the extradural or epicranial drains following craniotomy. We encountered an unusual complication with the use of the vacuum drain after an elective aneurysmal clipping surgery. Our case is an iatrogenic intracranial hypotension leading to a clinically significant and potentially fatal complication.