Transcranial Doppler

Transcranial Doppler (TCD) is a bedside, non-invasive, reproducible, non-expensive neuromonitoring device which can be used in many clinical scenarios. Based on the principle of the Doppler shift, blood flow velocity (FV) in the cerebral vessels can be measured. It should be noted that TCD measures blood FV and not the cerebral blood flow (CBF). However, in a given condition, FV can be used as a surrogate marker for vessel diameter or CBF. Indirectly, it can also measure the CBF and the intracranial pressure. This review describes briefly the method of using the equipment and the various indices that can be measured. The applications of TCD are varied. The review also gives an account of the various clinical situations where TCD can be used. An inter-operator variability is an important limiting factor with the use of the TCD. However, in many of clinical scenario, the TCD can still be used to guide for decision-making

Anaesthetic management in patients with glucose-6-phosphate dehydrogenase deficiency undergoing neurosurgical procedures

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is an X-linked recessive enzymopathy responsible for acute haemolysis following exposure to oxidative stress. Drugs which induce haemolysis in these patients are often used in anaesthesia and perioperative pain management. Neurosurgery and few drugs routinely used during these procedures are known to cause stress situations. Associated infection and certain foodstuffs are also responsible for oxidative stress. Here, we present two patients with G-6-PD deficiency who underwent uneventful neurosurgical procedures. The anaesthetic management in such patients should focus on avoiding the drugs implicated in haemolysis, reducing the surgical stress with adequate analgesia, and monitoring for and treating the haemolysis, should it occur

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

Effects of Phenytoin Therapy on Bispectral Index and Haemodynamic Changes Following Induction and Tracheal Intubation

Laryngoscopy and tracheal intubation (LTI) increase blood pressure and heart rate (HR). Intensity of these changes is influenced by the anaesthetic depth assessed by the bispectral index (BIS). We determined the effect of phenytoin on anaesthetic depth and its influence on haemodynamics following LTI. Fifty patients of ASA grades I and II on oral phenytoin 200 to 300mg per day for more than one week were compared with 48 control patients. Standard anaesthesia technique was followed. BIS, non invasive mean blood pressure (MBP) and HR were recorded 30, 60, 90 and 120 sec after LTI. Phenytoin group needed lesser thiopentone for induction, 5 mg (1.1) vs. 4.3 mg (0.7) [p=0.036]. BIS was significantly lower in the phenytoin group vs. the control 30, 60, 90 and 120 sec after LTI [43.1 (16.0) vs. 48.9 (14.9), p=0.068, 56.3 (16.7) vs. 64.3 (14.4), p=0.013, 59.8 (15.8) vs. 67.5 (12.1), p=0.008, 62.6 (14) vs. 68.9 (11.2), p=0.017, and 64.2 (11.3) vs. 69 (11.7), p=0.033], respectively. MBP was also lower in the phenytoin group 30, 60, 90 and 120 sec after LTI [112.8 mmHg (13.8), vs. 117.9 mmHg (18) p=0.013, 108.6 (12.8) vs. 117.5 (16) p=0.003, 106.1 mmHg (14.1) vs. 113.2 mmHg (14.9), p=0.017, 101.8 mmHg (13.8) vs. 109.5 mmHg (14.1), p=0.007], respectively. HR was lower in phenytoin group at 30 sec. (p=0.027), 60 sec (p=0.219), and again at 120 sec (p=0.022). Oral phenytoin therapy for over a week results in greater anaesthetic depth as observed using BIS, which also attenuated haemodynamic response of LTI