Patients Who Benefit from Intracranial Pressure Monitoring without Cerebrospinal Fluid Drainage After Severe Traumatic Brain Injury.

BACKGROUND: India has a high traumatic brain injury (TBI) burden and intracranial pressure monitoring (ICP) remains controversial but some patients may benefit. OBJECTIVE: To examine the association between ICP monitor placement and outcomes, and identify Indian patients with severe TBI who benefit from ICP monitoring. METHODS: We conducted a secondary analysis of a prospective cohort study at a level 1 Indian trauma center. Patients over 18 yr with severe TBI (admission Glasgow coma scale score < 8) who received tracheal intubation for at-least 48 h were examined. Propensity-based analysis using inverse probability weighting approach was used to examine ICP monitor placement within 72 h of admission and outcomes. Outcomes were in-hospital mortality and Glasgow Outcome Scale (GOS) score at discharge, 3, 6, and 12 mo. Death, vegetative, or major impairment defined unfavorable outcome. RESULTS: The 200 patients averaged 36 [18 to 85] yr of age and average injury severity score of 31.4 [2 to 73]. ICP monitors were placed in 126 (63%) patients. Patients with ICP monitor placement experienced lower in-hospital mortality (adjusted relative risk [aRR]; 0.50 [0.29, 0.87]) than patients without ICP monitoring. However, there was no benefit at 3, 6, and 12 mo. With ICP monitor placement, absence of cerebral edema (aRR 0.54, 95% confidence interval 0.35-0.84), and absence of intraventricular hemorrhage (aRR 0.52, 95% confidence interval 0.33-0.82) were associated with reduced unfavorable outcomes. CONCLUSION: ICP monitor placement without cerebrospinal fluid drainage within 72 h of admission was associated with reduced in-patient mortality. Patients with severe TBI but without cerebral edema and without intraventricular hemorrhage may benefit from ICP monitoring.

Comparative incidence of cardiovascular changes during venous air embolism as detected by transesophageal echocardiography alone or in combination with end tidal carbon dioxide tension monitoring.

The objective of our study was to compare the incidences of cardiovascular disturbance during venous air embolism (VAE) episodes detected using transesophageal echocardiography (TEE) and end tidal carbon dioxide (ETCO(2)) tension monitoring. We retrospectively analyzed the anesthesia records of patients who underwent posterior fossa surgery while in the sitting position and who were simultaneously monitored using both TEE and ETCO(2) tension monitoring. Data on the occurrence of VAE and the cardiovascular changes associated with it were recorded. Patients were divided into the ETCO(2)-positive group (both TEE and ETCO(2) tension monitoring indicated VAE) and the ETCO(2)-negative group (TEE alone indicated VAE, no significant drop in ETCO(2)). No instances of cardiovascular disturbance were detected in the ETCO(2)-negative group, whereas the incidences of tachycardia and hypotension were 20% and 30%, respectively, in the ETCO(2)-positive group. None of the episodes of VAE detected by TEE (without a fall in ETCO(2)) were clinically significant. We conclude that ETCO(2) monitoring is sensitive enough to detect hemodynamically significant VAE episodes.

Intra-operative electrocorticography in lesional epilepsy.

Intra-operative electrocorticography (ECoG) is useful in epilepsy surgery to delineate margins of epileptogenic zone, guide resection and evaluate completeness of resection in surgically remediable intractable epilepsies. The study evaluated 157 cases (2000-2008). The preoperative evaluation also included ictal SPECT (122) and PET in 32 cases. All were lesional cases, 51% (81) of patients had >1 seizure/day and another 1/3rd (51) had >1/week. Pre and post resection ECoG was performed in all cases. A total of 372 recordings were performed in 157 cases. Second post-operative recordings (42) and third post-operative recordings (16) were also performed. Site of recordings included lateral temporal (61), frontal (39), parietal (37), hippocampal (16) and occipital (4). 129/157 cases (82%) showing improvement on ECoG, 30/42 cases showed improvement in 2nd post resection, 8/16 showed improvement in the 3rd post-operative ECoG. 116/157 (73%) patients had good outcome (Engel I and II) at follow up (12-94 months, mean 18.2 months). Of these, 104 patients (80%) showed improvement on post-operative ECoG. 12 had good outcome despite no improvement on ECoG. The improvement in ECoG correlated significantly with clinical improvement [Sensitivity: 100% (95% CI; 96-100%); specificity: 68.3% (95% CI; 51.8-81.4%); positive predictive value: 89.9% (95% CI, 83.1-94.3%); negative predictive value: 100% (95% CI, 85-100%)]. The level of agreement was 91.72% (kappa: 0.76). Concluding, pre and post resection ECoG correlated with its grade of severity and clinical outcome.

An assessment of the predictors of difficult intubation in patients with acromegaly.

Various clinical signs have been used for assessing difficult intubation in patients with acromegaly. These signs include the modified Mallampati classification, measurement of thyromental distance and head and neck movements. Some authors have also tried to establish a relationship between growth hormone levels and difficult intubation. We hypothesized that duration of symptoms in patients with acromegaly may have an association with difficult airway and difficult laryngoscopy. In this prospective study we evaluated tests of airway assessment such as: (i) the Mallampati grade; (ii) the thyromental distance; and (iii) the laryngoscopic grade (Cormack-Lehane). The growth hormone levels and the duration of disease symptoms were also examined. Significant correlation was observed between the Cormack-Lehane and Mallampati gradings (p = 0.05; rho = 19.3%), and between the thyromental distance and the duration of the symptoms (p = 0.03; rho = 26.9%). The incidence of Mallampati III and IV grades was higher in patients with acromegaly. Increased thyromental distance was noted in patients with a long duration of disease. However, increased thyromental distance was not associated with difficult laryngoscopy.

Saline flush test for bedside detection of misplaced subclavian vein catheter into ipsilateral internal jugular vein.

BACKGROUND: The most common misplacement during subclavian vein (SCV) catheterization is into the ipsilateral internal jugular vein (IJV). Chest radiography is the gold standard for the confirmation of correct placement. However, it is time-consuming and has the disadvantage of radiation exposure. We assessed the sensitivity and specificity of our previously reported 'flush test' for confirming correct central line placement. METHODS: All neurosurgical patients who underwent successful SCV catheterization on the right side by an infraclavicular approach were enrolled in this study. The flush test was performed by injecting 10 ml of normal saline in the distal port of catheter, while anterior angle of ipsilateral neck was palpated by an independent observer. A thrill of fluid elicited on the palm of hand (positive test) was suggestive of misplaced catheter into ipsilateral IJV. This was confirmed with chest fluoroscopy. RESULTS: SCV catheterization was performed in 570 patients. The flush test was positive in 19 patients (3.3%) and negative in 551 patients (96.7%). There were 26 (4.6%) misplacements as detected by chest radiography; 19 entered the IJV (3.3%) and seven the contralateral SCV (1.2%). In all patients who had a misplaced catheter into the ipsilateral IJV, the flush test results were positive, whereas the results were negative in patients who had normally placed catheter or misplaced catheter elsewhere. It was found that the test had 100% sensitivity and specificity to detect misplacement of SCV catheter into the ipsilateral IJV. CONCLUSIONS: Saline flush test is a simple and sensitive bedside test that successfully detects misplaced SCV catheters into ipsilateral IJV.

Intra-ocular pressure changes associated with intubation with the intubating laryngeal mask airway compared with conventional laryngoscopy.

This open, prospective, randomised study was designed to evaluate the changes in intra-ocular pressure and haemodynamics after tracheal intubation using either the intubating laryngeal mask airway (ILMA) or direct laryngoscopy. Sixty adult patients, ASA physical status 1 or 2 with normal intra-ocular pressure were randomly allocated to one of the two techniques. Anaesthesia was induced with propofol followed by rocuronium. Tracheal intubation was performed using either the ILMA or Macintosh laryngoscope. Intra-ocular pressure, heart rate and blood pressure were measured immediately before and after tracheal intubation and then minutely for five minutes. In the laryngoscopy group there was a significant increase in intra-ocular pressure (from 7.2+/-1.4 to 16.8+/-5.3 mmHg, P<0.01), which did not return to pre-intubation levels within five minutes, and also in mean arterial pressure after tracheal intubation, which returned to baseline levels after five minutes. In the ILMA group there were no significant changes in intra-ocular pressure (from 7.6+/-1.8 to 10.4+/-2.8 mmHg, P >0.05) or mean arterial pressure after tracheal intubation. Time to successful intubation was longer with the ILMA, 56.8+/-7.8 seconds, compared with the laryngoscopy group, 33+/-3.6 seconds (P<0.01). Mucosal trauma was more frequent with the ILMA (eight of 30) compared with the laryngoscopy group (three of 30) (P<0.01). The postoperative complications were comparable. In terms of minimising increases in intra-ocular pressure and blood pressure, we conclude that the ILMA has an advantage over direct laryngoscopy for tracheal intubation.

Intracranial pressure changes during Valsalva manoeuvre in patients undergoing a neuroendoscopic procedure.

BACKGROUND: The Valsalva manoeuvre results in an increase in intrathoracic pressure which alters the systemic and cerebral circulations significantly. We decided to record changes in the intracranial pressure and cerebral perfusion pressure resulting from a Valsalva manoeuvre in anaesthetised patients. METHODS: 11 patients of either gender submitted to surgical neuroendoscopic procedures were studied. Standard general anaesthesia was maintained for the procedure in all the patients. Passive Valsalva manoeuvres were carried out by squeezing the bag of the closed breathing circuit to maintain an airway pressure of 20 cm H2O above peak inspiratory airway pressure for 10 seconds. The variables heart rate, mean arterial pressure, intracranial pressure and cerebral perfusion pressure were noted. The variables were recorded again after the surgical correction. All cardiovascular and cerebrovascular variables were compared using the Wilcoxon sign-rank test. We considered a value of p less than 0.05 to be statistically significant. RESULTS: The median age of the 11 patients was 22 years (range: 15-43) and median weight was 50 kg (range: 30-78). On comparing the variables during the two Valsalva manoeuvres, we found significant changes in HR, ICP and CPP after the surgical correction. No complications were encountered in any of the patients. CONCLUSION: There was a significant reduction in cerebral perfusion pressure during the Valsalva manoeuvre in both stages. This was a result of change in either the intracranial pressure or the mean arterial pressure. Although our patients did not suffer a clinically significant reduction in cerebral perfusion pressure and so had an uneventful recovery, the effect of Valsalva manoeuvre on cerebral perfusion pressure cannot be denied. The marked haemodynamic changes clearly warrant a cautious use of this manoeuvre in neurosurgical practice.

Complications related to positioning in posterior fossa craniectomy.

To compare complications associated with surgical position, a retrospective study was conducted on 260 patients who underwent posterior fossa craniectomy. Data collected from the records included demographic profile, American Society of Anesthesiologists' physical status score, neurological status, cranial nerve involvement, associated medical illnesses, anaesthetic technique, patient position, haemodynamic changes, duration of surgery, venous air embolism (VAE), blood loss/transfusion, postoperative complications, duration of ICU stay, and postoperative neurological status. Statistical analysis was done using the Chi-square test and independent t-tests. The demographic profile and preoperative associated medical illnesses of patients were comparable between groups. The incidence of end-tidal carbon dioxide (EtCO2) detected VAE was more (p=0.00) in the sitting position than the horizontal positions (15.2% vs. 1.4%). Blood loss/transfusion and the duration of surgery were significantly higher in the horizontal position (p<0.05). Brainstem handling was the most common cause of prolonged postoperative mechanical ventilation and was seen more in the sitting position. Lower cranial nerve functions were preserved better in the sitting position (p<0.05). Most postoperative complications (surgical or otherwise) were comparable between the groups (p>0.05). Most patients in both groups developed mild-to-moderate disability with independent lifestyle at the seventh postoperative day. To conclude, both sitting and horizontal positions can be used safely in posterior fossa surgeries.

Scheduled prophylactic ondansetron administration did not improve its antiemetic efficacy after intracranial tumour resection surgery in children.

BACKGROUND AND OBJECTIVE: Postoperative nausea and vomiting after craniotomy may increase intracranial pressure and morbidity in children. This prospective, randomized, placebo-controlled and double-blinded study was designed to evaluate the antiemetic efficacy of prophylactic ondansetron after intracranial tumour resections in children. METHODS: Ninety children were divided into three groups and received saline (Group 1), ondansetron 150 microg kg-1 intravenously at dural closure (Group 2) or two doses of ondansetron 150 microg kg-1 intravenously, the second dose repeated after 6 h (Group 3). Episodes of nausea, emesis and side-effects were noted for 24 h postoperatively. RESULTS: Overall 24 h incidence of postoperative nausea and vomiting was not significantly different among the three groups (9 (37.5%) in Group 1 vs. 7 (27%) in Group 2 and 8 (32%) in Group 3, P = 0.73). No difference in rescue antiemetic treatment or postoperative nausea and vomiting at specific time intervals (0-6 and 6-24 h postoperative period) was seen among the three groups. No significant side-effects were noted in any of the three groups. CONCLUSIONS: Ondansetron, in this study of 90 children, was not very effective in preventing nausea and vomiting after neurosurgical operations.

Haemodynamic changes after intracisternal papaverine instillation during intracranial aneurysmal surgery.

Cerebral vasospasm remains a significant cause of mortality and morbidity after aneurysmal subarachnoid haemorrhage. Use of either intra-arterial or intracisternal papaverine as an alternative treatment of refractory cerebral vasospasm has been associated with various complications including haemodynamic instabilities. However, our search in literature did not reveal association of bradycardia and hypotension with the use of papaverine by either of these routes. Here, we describe a case of anterior communicating artery aneurysm with hydrocephalus. The patient underwent craniotomy and clipping of the aneurysm followed by third ventriculostomy. Instillation of papaverine at the surgical site caused significant haemodynamic changes possibly because of stimulation of hypothalamus in the third ventricle or vagal nuclei in the fourth ventricle, or even both. We recommend cautious use of intracisternal papaverine in such scenario especially when third ventriculostomy has been performed as an adjunct surgical procedure.

Severe bradycardia and hypotension after connecting negative pressure to the subgaleal drain during craniotomy closure.

Negative pressure drainage systems are often used after craniotomy for evacuation of potential bleeding. There are several reports of haemodynamic disturbances with epidural negative pressure drainage, but such reports are very few for subgaleal drains placed over the bone flap. We report a case in which a patient developed severe cardiovascular disturbances after the vacuum drainage was connected to a subgaleal drain after craniotomy for aneurysm clipping. The patient had no significant cardiac history, had an uneventful intra-operative course and yet developed bradycardia and hypotension, which were reproducible and severe enough to require atropine administration. Anaesthetists must be aware of these effects, so that they can anticipate and treat such complications.

Effects of stellate ganglion block on cerebral haemodynamics as assessed by transcranial Doppler ultrasonography.

BACKGROUND: Stellate ganglion block (SGB) causes vasodilatation in the skin of the head and neck because of regional sympathetic block. Its effects on cerebral haemodynamics, in health or in disease, are not clear. We evaluated the effects of SGB on ipsilateral middle cerebral artery flow velocity (MCAFV), estimated cerebral perfusion pressure (eCPP), zero flow pressure (ZFP), carbon dioxide reactivity (CO2R) and cerebral autoregulation using transcranial Doppler ultrasonography (TCD). METHODS: Twenty male patients, with pre-existing brachial plexus injury, and undergoing SGB for the treatment of complex regional pain syndrome of the upper limb, were studied. For SGB, 10 ml of plain lidocaine 2% was used and the onset of block was confirmed by presence of ipsilateral Horner's syndrome. The MCAFV, eCPP, ZFP, CO2R, and cerebral autoregulation were assessed before and after SGB using established TCD methods. The changes in these variables were analysed using Wilcoxon's signed rank test. RESULTS: The block caused a significant decrease in MCAFV from median (inter-quartile range) value of 61 (53, 67) to 55 (46, 60) cm s(-1), a significant increase in eCPP from 59 (51, 67) to 70 (60, 78) mm Hg, and a significant decrease in ZFP from 32 (26, 39) to 25 (16, 30) mm Hg. There were no significant changes in CO2R or cerebral autoregulation. CONCLUSION: The increase in eCPP, decrease in ZFP, and no changes in CO2R or cerebral autoregulation suggest that the SGB decreases cerebral vascular tone without affecting the capacity of the vessels to autoregulate. These effects may be of therapeutic advantage in relieving cerebral vasospasm in certain clinical settings.

Comparative incidence of venous air embolism and associated hypotension in adults and children operated for neurosurgery in the sitting position.

BACKGROUND AND OBJECTIVE: Venous air embolism is a constant threat during neurosurgery performed in the sitting position. No large prospective study has compared the incidence of venous air embolism and associated hypotension between adults and children. METHODS: Four hundred and thirty patients (334 adults, 96 children) scheduled to undergo planned posterior fossa surgery in the sitting position (between January 1989 to December 1994) were studied with end-tidal carbon dioxide monitoring. Intraoperatively, a sudden and sustained decrease in end-tidal carbon dioxide tension of >0.7 kPa was presumed to be due to venous air embolism. Management during the episode was on the established guidelines. Hypotension (decrease in systolic arterial pressure of 20% or more from the previous level) was treated with crystalloids and/or a vasopressor. RESULTS: Capnometry detected a 28% incidence rate of air embolism in adults (93/334) and a 22% incidence rate in children (21/96) (P = 0.29). In both groups, the highest incidence rate of embolism took place during muscle handling (44% of adults versus 38% of children, P = 0.8). Embolic episodes were accompanied by hypotension in 37% of adults (34/93) and in 33% of children (7/21) (P = 0.98). To restore arterial pressure to pre-embolic levels, 53% of adults (18/34) and 43% of children (3/7) were administered vasopressors (P = 0.94). There was no intraoperative mortality. The surgical procedure on one adult was abandoned because of persistent hypotension following the embolic episode. CONCLUSION: The incidence of venous air embolism and consequent hypotension is similar in adults and children.