Kamath Sriganesh

An equiosmolar study on early intracranial physiology and long term outcome in severe traumatic brain injury comparing mannitol and hypertonic saline.

The impact of hypertonic saline (HTS) on long term control of intracranial hypertension (ICH) is yet to be established. The current prospective randomized controlled study was carried out in 38 patients with severe traumatic brain injury (TBI). Over 450 episodes of refractory ICH were treated with equiosmolar boluses of 20% mannitol in 20 patients and 3.0% HTS in 18 subjects. Intracranial pressure (ICP) was monitored for 6days. ICP and cerebral perfusion pressure (CPP) were comparable between the groups. The mannitol group had a progressive increase in the ICP over the study period (p=0.01). A similar increase was not seen in the HTS group (p=0.1). The percentage time for which the ICP remained below a threshold of 20 mmHg on day6 was higher in the HTS group (63% versus 49%; p=0.3). The duration of inotrope requirement in the HTS group was less compared to the mannitol group (p=0.06). The slope of fall in ICP in response to a bolus dose at a given baseline value of ICP was higher with HTS compared to mannitol (p=0.0001). In-hospital mortality tended to be lower in the HTS group (3 versus 10; p=0.07) while mortality at 6 months was not different between the groups (6 versus 10; p=0.41). Dichotomized Glasgow Outcome Scale scores at 6months were comparable between the groups (p=0.21). To conclude, immediate physiological advantages seen with HTS over mannitol did not translate into long term benefit on ICP/CPP control or mortality of patients with TBI.

An abrupt reduction in end-tidal carbon-dioxide during neurosurgery is not always due to venous air embolism: a capnograph artefact

Venous air embolism (VAE) is a well recognized complication during neurosurgery. Pre-cordial doppler and trans-esophageal echocardiography are sensitive monitors for the detection of VAE. A sudden, abrupt reduction in the end-tidal carbondioxide (ETCO2) pressure with associated hypotension during neurosurgery might suggest VAE, when more sensitive monitors are not available. We describe an unusual cause for sudden reduction in ETCO2 during neurosurgery and discuss the mechanism for such presentation.

Acute kidney injury in survivors of surgery for severe traumatic brain injury: Incidence, risk factors, and outcome from a tertiary neuroscience center in India

Abstract Background. Non-neurological complications like acute kidney injury (AKI) can affect outcome of traumatic brain injury (TBI). This study aims to analyze the incidence, predictive factors, and impact of AKI in operated patients with severe TBI. Methods. We retrospectively reviewed the data of 395 patients who underwent surgery for severe TBI and survived to be discharged from the hospital over a 1-year period. Of these, 95 patients were finally included in the analysis. Their demographic data, laboratory parameters, and clinical courses were reviewed. Diagnosis and staging of AKI was made using Acute Kidney Injury Network (AKIN) criteria. Results. The incidence of AKI was 11.6% (11 patients). Out of the11 patients who had AKI, 7 were in stage I (63.6%), 3 were in stage II (27.3%), and 1 in stage III (9.1%). Nine Patients (81.8%) developed AKI within 5 days of admission. Aminoglycoside therapy had an association with occurrence of AKI. There was no mortality and none of the patients required renal replacement therapy (RRT). Renal function of all these patients returned to baseline before hospital discharge. Hospital stay and intensive care unit (ICU) stay were longer and Glasgow coma scale (GCS) was lower in patients with AKI when compared with patients without AKI group at discharge. Conclusion. Reversible AKI without need for RRT occurred in nearly12% of patients with severe TBI requiring surgical intervention. Aminoglycoside therapy was the only predictive factor for the occurrence of AKI. Patients with AKI have a longer period of mechanical ventilation, longer ICU and hospital stay, and poorer GCS at discharge.

Indocyanine green dye administration can cause oxygen desaturation

Indocyanine green (ICG) video-angiography is used intraoperatively to visualize the vascular integrity during neurovascular surgical procedures [1]. Oxygen desaturation following ICG injection has not been described previously nor is it mentioned in the list of adverse effects of the dye by the manufacturer. We report here a 42-year-old female who underwent clipping of the basilar artery aneurysm. The ICG dye (Aurogreen , Aurolab, Madurai, India) was injected at the recommended dose of 0.25 mg/kg before clip application to visualize the vessels and their branches. After clipping, ICG was repeated to confirm correct clip placement and patency of parent and perforator vessels. On both occasions, there was reduction in the pulse-oximeter saturation reading (99–96 %), the decrease more after the second dose (94 %). We had a monitor (Radical-7 Pulse CO-Oximeter (Masimo Corporation, Irvine, CA) where we observed that the methemoglobin level too increased during desaturation from 0.2 to 0.9 % and gradually returned to previous value in 8 min along with return of saturation to 99 %. The patient did not have any complications associated with these changes. This finding was reproducible and consistent in other patients as well. Decreased pulse-oximeter reading has been observed in dogs following ICG administration [2]. Therefore, though the change is insignificant and transient, it is desirable that this effect be listed by the manufacturer in the list of side effects. Caution should be exercised when repeat doses of ICG are administered especially within short periods of time.

Clonidine as a sole sedative agent for MRI study in a child with Joubert syndrome

alize the glottis (grade 4 C–L view with direct laryngoscopy), and the case was rescheduled and proceeded successfully following asleep fiberoptic nasotracheal intubation. The plan for airway management for this patient was GlideScope Cobalt Infant Video Laryngoscopy following inhalation induction. This approach revealed a clear view of the glottis, and a size 5.0 cuffed Portex tracheal tube was easily inserted in the trachea. Direct laryngoscopy with a Wisconsin 1 blade revealed a grade 4 C–L view. Pediatric anesthesiologists experienced in difficult airway management will often use a small straight blade for tracheal intubation even in older children. This combined with a retromolar or paraglossal technique of laryngoscopy allows for an improved glottic view in micrognathic patients (3). Similarly, the smaller and narrower infant GlideScope Cobalt Video Laryngoscope may allow for a superior glottic view in older children with retroor micrognathia by allowing for a greater degree of mobility and maneuverability once inserted in the oropharynx. The authors feel that the infant Glidescope is useful in older patients with severe micrognathia because the shorter distance to the glottis will allow the infant scope to visualize the glottis and allow for more room in the oral cavity because of its smaller size. In conclusion we present a series of three cases wherein the infant GlideScope Cobalt Video Laryngoscope proved vitally instrumental in facilitating tracheal intubation in older children with retro ⁄ micrognathia. In two cases, flexible fiberoptic laryngoscopy had failed and the infant GlideScope Cobalt Video Laryngoscope proved useful even in the presence of epistaxis. The authors recommend the infant GlideScope Cobalt Video Laryngoscope be considered when planning the airway management not only of infants but also of older children with retroor micrognathia. This manuscript highlights the following teaching points: (i) The Glidescope can be a useful teaching tool and has been shown to be valuable in patients with a difficult airway; (ii) the approach to the patient with severe retrognathia requires an appreciation for the extremely short distance between the mandible and glottis and (iii) an airway instrument designed for infants (such as the infant GlideScope Cobalt Video Laryngoscope) may be useful in larger patients with severe retroor micrognathia. C E N G I Z K A R S L I T A R A D E R Assistant Professor, Staff Anesthesiologist, Department of Anesthesia and Pain Medicine, University of Toronto, The Hospital for Sick Children, Toronto, Canada (email: cengiz.karsli@sickkids.ca)

Effect of Hyperoxia on Cerebral Blood Flow Velocity and Regional Oxygen Saturation in Patients Operated on for Severe Traumatic Brain Injury–The Influence of Cerebral Blood Flow Autoregulation

BACKGROUND The effect of normobaric hyperoxia on brain oxygenation in the presence or absence of intact autoregulation has not been studied previously in acute traumatic brain injury (TBI). METHODS In this prospective clinical investigation of 50 patients operated on for severe TBI, cerebral blood flow (CBF) velocity in the middle cerebral artery was measured using transcranial Doppler. Regional cerebral oxygen saturation using near-infrared spectroscopy at 3 different fractions of inspired oxygen (Fio2) (0.4, 0.6, and 1) was measured in the last 25 of these patients. RESULTS There was no difference in the hemodynamic and respiratory variables except for Pao2, which increased with increasing Fio2. The CBF velocities and pulsatility indices did not vary at different levels of Fio2 (0.4, 0.6, and 1) both on the operated and on the nonoperated side. The regional cerebral oxygen saturation as evaluated by bifrontal near-infrared spectroscopy sensors increased with increasing Fio2 on the operated (pathologic) side with impaired cerebral autoregulation and not with intact autoregulation. CONCLUSIONS In severe TBI, middle cerebral artery CBF velocity is not affected by hyperoxia in both the pathologic and the normal side. The cerebral oxygen saturation increased with increasing arterial hyperoxia in the operated cerebral hemisphere and remained within baseline range in the nonoperated hemisphere. Impairment in the cerebral autoregulation in the pathologic hemisphere contributes to this luxury oxygenation.

Incidence and risk factors for oxygen desaturation during recovery from modified electroconvulsive therapy: A prospective observational study.

BACKGROUND AND AIMS Electroconvulsive therapy (ECT) is an established modality of treatment for severe psychiatric illnesses. Among the various complications associated with ECT, oxygen desaturation is often under reported. None of the previous studies has evaluated the predictive factors for oxygen desaturation during ECT. The objective of this study was to evaluate the incidence of oxygen desaturation during recovery from anesthesia for modified ECT and evaluate its risk factors in a large sample. MATERIALS AND METHODS All patients aged above 15 years who were prescribed a modified ECT for their psychiatric illness over 1 year were prospectively included in this observational study. The association between age, body mass index (BMI), doses of thiopentone and suxamethonium, stimulus current, ECT session number, pre- and post-ECT heart rate and mean arterial pressure, seizure duration, and pre- and post ECT oxygen saturation, was systematically studied. RESULTS The incidence of oxygen desaturation was 29% (93/316 patients). Seizure duration and BMI were found to be significantly correlated with post ECT desaturation. CONCLUSION In this prospective observational study, the incidence of oxygen desaturation during recovery from anesthesia for ECT was high. The study identified obesity and duration of seizure as the independent predictors of this complication. This knowledge is likely to help in identifying and optimizing such patients before subsequent ECT sessions.

Effect of Atropine Premedication on Cardiac Autonomic Function During Electroconvulsive Therapy: A Randomized Crossover Study

Objectives Electroconvulsive therapy (ECT) results in significant cardiovascular changes. The acute cardiac autonomic changes during ECT remain unexplored. The primary objective of this study was to compare autonomic dysfunction with and without atropine premedication during ECT and secondarily to evaluate dysautonomia across psychiatric diagnoses before and after ECT. Methods In this crossover study, 41 psychiatric patients were monitored during 82 ECT sessions. Patients were randomized either to receive atropine or not to receive atropine during their second ECT session and were crossed over during their third session. Heart rate, blood pressure, and oxygen saturation were continuously monitored from stimulus application until 300 seconds after ECT. Demographic characteristics and ANSiscope indices derived pre- and post-ECT were collected. Results Autonomic dysfunction (%) before ECT was similar between atropine and no-atropine sessions (32.4 ± 15.7 vs 32.8 ± 16.7; 95% confidence interval, −7.6 to 6.7; P = 0.90) but increased significantly after ECT to 60.9 ± 16.3 and to 47.0 ± 17.3, respectively, and this difference was significant (95% confidence interval, 6.5–21.3; P < 0.001). There was no difference in the autonomic function across psychiatric diagnoses both before (P = 0.07) and after ECT (P = 0.12). Conclusions Cardiac autonomic dysfunction worsens after ECT in patients with psychiatric illnesses and to a significantly greater extent with atropine premedication. The degree of dysautonomia is similar across various psychiatric diagnoses both before and after ECT. Atropine premedication during ECT should be restricted to select patients susceptible to bradyarrhythmia and could be avoided in others.

Audit of the Functioning of the Elective Neurosurgical Operation Theater in India: A Prospective Study and Review of Literature

BACKGROUND Knowledge about the utilization of the operation theater (OT) is essential to improve its efficiency. This study evaluated the neurosurgical operation theater utilization in a neurosciences teaching hospital. METHODS Data collected included OT start time, delay in start, anesthesia induction time, surgical preparation time, anesthesia recovery time, operating time, time between cases, and theater closing time. RESULTS Five hundred thirty-seven surgeries were performed during the study period. The percentage of time used for anesthesia induction, actual surgical procedure, recovery from anesthesia, and theater preparation between the two cases were 8%, 70%, 6% and 5%, respectively. Fourteen percent of scheduled cases were cancelled. On 220 occasions (70.51%), theater was over-run. Late start contributed to loss of 8370 minutes (140 hours) of theater time. CONCLUSIONS This study identified the proportion of time spent on each activity in the neurosurgical OT. This knowledge is likely to facilitate better planning of neurosurgical theater schedule and result in optimal utilization.

Carotid Cavernous Fistula

A 26-year-old man who had had blunt trauma to the head 2 months earlier presented with rapidly progressive swelling, pain, and diminishing vision in the left eye. The physical examination of the left eye revealed chemosis, pulsating proptosis, and an ulcerated cornea.