Sonia Bansal

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.

Perioperative stroke following anterior cervical discectomy.

We describe a case of postoperative stroke in a patient undergoing anterior cervical discectomy caused by a combination of intraoperative retraction of an atherosclerotic carotid vessel and arterial hypotension.

Massive cerebral air embolism during stent-assisted coiling of internal carotid artery aneurysm

The clinical and radiological findings are given in Table 1. In both the patients, there was no desaturation throughout the procedure. Dexamethasone and mannitol was given to prevent cerebral edema and loading dose of phenytoin was administered for seizures prophylaxis. Both patients developed seizures within 24 h of Neurointensive Care Unit (NICU) stay. Case 1 received only benzodiazepine as treatment for seizures, whereas Case 2 received in addition low‐dose thiopentone infusion for seizures and vasopressors to induce hypertension (systolic BP ≥ 150 mmHg). In Case 1, there was no improvement in the neurological status. She had tracheostomy and weaned from ventilator and later transferred to a general hospital in a severely disabled state. Case 2 improved completely and was extubated on day 3. The exact source of air entry could not be identified in Case 1 and it was assumed that air might have entered during hand injection of the contrast agent. In Case 2, the pressurized nimodepine arterial flush bottle was found empty.

ECG contamination of EEG signals: effect on entropy

Entropy™ is a proprietary algorithm which uses spectral entropy analysis of electroencephalographic (EEG) signals to produce indices which are used as a measure of depth of hypnosis. We describe a report of electrocardiographic (ECG) contamination of EEG signals leading to fluctuating erroneous Entropy values. An explanation is provided for mechanism behind this observation by describing the spread of ECG signals in head and neck and its influence on EEG/Entropy by correlating the observation with the published Entropy algorithm. While the Entropy algorithm has been well conceived, there are still instances in which it can produce erroneous values. Such erroneous values and their cause may be identified by close scrutiny of the EEG waveform if Entropy values seem out of sync with that expected at given anaesthetic levels.

Good airway reflexes and normal sensorium do not assure safe tracheal extubation in patients with cerebral hemispheric pathology.

Abstract Following brain injury, return of consciousness and cough reflex are presumed to be associated with safe airway. We describe two patients who had a normal cough reflex, but impaired swallowing, which led to prolonged hospital stay. This report highlights the dissociation between the cough reflex and swallowing function in such patients.

Quantitative analysis of changes in cerebral oxygenation during induction of anaesthesia and in different positions in spine surgery using near-infrared spectroscopy

168 Journal of Neuroanaesthesiology and Critical Care | Vol. 3 • Issue 2 • May-Aug 2016 | Background and Objectives: Additional dose of anticonvulsants are administered during supratentorial craniotomy. It has impact on recovery time, haemodynamics and depth of anaesthesia. Our study compared the recovery time in patients who received additional anticonvulsant with those who received the regular dose during craniotomy. Patient and Methods: After the Institutional Review Board approval, the study was carried out in 36 patients who underwent supratentorial craniotomy. Patients were divided into two groups; Group 1: Regular dose, Group 2: Additional dose. Patients were anaesthetised using standard anaesthesia protocol. Anticonvulsant was administered during craniotomy, and the haemodynamics and changes in bispectral index were noted during and 1 h after administration of the anticonvulsant. Plasma anticonvulsant levels were measured before and after craniotomy. Extubation time, time to open eyes, obeys commands and orientations were noted. Patients were followed up for 48 h to note the occurrence of seizures. Results: Of 36 patients, 19 patients received regular dose; 17 received an additional dose. Age, sex, weight, tumour location and tumour pathology, dose of propofol, fentanyl administered were comparable between the two groups. There was no significant difference in recovery time between the two groups as they were analysed as additional versus regular dose. However, the subgroup analysis showed significant delay in recovery especially, time to obey commands (>15 min) and time to get orientation (>1 h) in patients who received additional dose of phenytoin. Although these differences looked clinically very significant, it was not statistically significant because of smaller sample size. Plasma anticonvulsant levels had significantly dropped in patients who received regular dose (P 0.004). There was a positive correlation between intravenous fluid administered and drop in plasma anticonvulsant level. Five patients had post-operative seizures, of which four had preoperative seizure. There was no correlation with postoperative plasma anticonvulsant levels and occurrence of post-operative seizures. Conclusion: Administration of additional dose of phenytoin causes delays the recovery and causes haemodynamic fluctuations. Administration of additional dose of sodium valproate did not affect either the recovery time or the haemodynamics. The presence of pre‐operative seizures is one of the significant risk factors for developing post-operative seizure. Due to the small sample size, it is very difficult to comment on the occurrence of post-operative seizures and the plasma anticonvulsant level. This warrants larger randomised control trials to see the correlation statistically.

Anesthetic management of a paraparetic patient with multiple lung bullae.

To JNA Readers: A 60-year-old man presented with history of a fall 6 months back after which he developed neck pain, lower limb weakness, and urinary retention. There were no respiratory complaints. Medical history was not significant. Hypertonia was present in both the lower limbs with power of 3/5. The lungs were clear on auscultation. Magnetic resonance imaging of the spine revealed cord compression at the cervical (C3-C5) and thoracic (T10) levels. Laminectomy at T10T11 and excision of T10-T12 ossified ligamentum flavum were planned. X-ray reports of the chest showed bilateral upper-zone focal abnormalities with fibrotic bands and emphysematous changes. Computed tomography scan of the chest showed bilateral gross pleural thickening, upper-zone lesions with fibrotic strands, and calcified mediastinal lymph nodes (Fig. 1A). On the right side, multiple large emphysematous bullae were seen (Fig. 1B). Radiologic findings were suggestive of pulmonary tuberculosis. Pulmonary function test revealed severe restriction. In view of emphysematous bullae, general anesthesia (GA) with spontaneous respiration was planned to avoid positive pressure ventilation (PPV). Patient was premedicated with 0.2mg of glycopyrrolate and 1mg of midazolam intravenously. Airway was anesthetized with 4% lignocaine nebulization, topical 10% spray, and transtracheal block. A dosage of 50mg of propofol and a dosage of 40mg IV fentanyl were given to facilitate intubation. Anesthesia was maintained using 1% to 2% sevoflurane and O2 with air (35:75). Analgesia was provided with fentanyl boluses. Throughout the procedure, spontaneous respiration was maintained (respiratory rate 8 to 12/min, end tidal carbon dioxide 40 to 42mm Hg). Airway pressures and systemic parameters were monitored carefully to diagnose the occurrence of pneumothorax at the earliest. Postoperatively, patient was breathing comfortably with no new complications. Bulla is a pathologic entity caused by a confluence of 2 or more terminal elements of bronchial tree. It may get infected or enlarge progressively and may lead to pneumothorax. It exists frequently in conditions like tuberculosis. Various anesthetic techniques have been tried in patients with bullae presenting for extrathoracic surgery such as GA with double-lumen tube,1 inhalational anesthetics and spontaneous ventilation,2 and awake craniotomy using dexmedetomidine sedation. Iwakura et al used spontaneous ventilation, although initially succinylcholine was used to facilitate intubation. Because of preoperative paraparesis, we avoided succinylcholine. To blunt airway reflexes, we used topical anesthesia and airway blocks. In another case report, authors have used laryngeal mask airway with epidural catheter in a spontaneously breathing patient. We did not consider regional anesthesia, despite being a good option in patients with lung bulla, in view of preoperative limb weakness. Placing a patient in prone position presents significant challenges to the anesthetist. A decrease in the mean arterial pressure, stroke volume, and the cardiac index can occur. Abdominal compression can worsen the obstruction to inferior vena cava leading to an increased surgical-site bleeding. Accidental extubation and endotracheal tube obstruction are other feared complications. Prone position increases functional residual capacity and improves oxygenation by reducing the ventilation perfusion mismatch. Spontaneous breathing can have synergistic effect with prone position. Active

Influence of acute haemodynamic changes on the oxygen saturation during electro-convulsive therapy

Background: Electro-convulsive therapy (ECT) is a safe and effective treatment for various psychiatric disorders. Among the various complications associated with ECT, acute haemodynamic responses and decrease in the oxygen saturation are the most common. The current study is designed to evaluate the relationship between the haemodynamic response and oxygen de-saturation occurring during ECT. Materials and Methods: Patients undergoing modified ECT for their psychiatric illness over a one-year period were prospectively included in this observational study. The following parameters were collected from each patient: Age, body mass index (BMI), doses of thiopentone and suxamethonium, stimulus current, ECT session number, pre-and post-ECT heart rate, systolic, diastolic and mean arterial pressure, seizure duration and pre- and post-ECT oxygen saturation. Results: The incidence of oxygen de-saturation was 27% (139/507 sessions). The change in the heart rate and systolic blood pressure caused by ECT and the BMI of the patient were independently predictive of the change in the oxygen saturation. Conclusions: The current study identified ECT-induced acute haemodynamic changes as independent predictors of severity of oxygen de-saturation.