H. H. Dash

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.

Catheter malplacement during central venous cannulation through arm veins in pediatric patients.

For successful catheter placement, central venous cannulation (CVC) through internal jugular vein and subclavian vein has been recommended in both adult and pediatric patients. But it carries a risk of serious complications, such as pneumothorax, carotid, or subclavian artery puncture, which can be life-threatening, particularly in critically ill children. So a prospective study was carried out to determine the success rate of correct catheter tip placement during CVC through antecubital veins in pediatric neurosurgical patients. A total of 200 pediatric patients (age 1-15 years) of either sex were studied. Basilic or cephalic veins of either arm were selected. All the patients were cannulated in the operation room under general anesthesia. Single lumen, proper size catheters (with stillete) were used for cannulation. The catheter was inserted in supine position with the arm abducted at right angle to the body and neck turned ipsilaterally. The length of insertion was determined from cubital fossa to the right second intercostal space. The exact position of the tip of the catheter was confirmed radiologically in ICU. Correct catheter tip placement was achieved in 98 (49%) patients. Multivariate logistic regression analysis of data shows that there was no statistically significant difference among correct and incorrect catheter tip placement in relation to factors including sex, side of cannulation (left or right), and type of vein (basilic or cephalic). The analysis of correct catheter tip placement in relation to age showed that the highest success rate was achieved in children of age group 6 to 10 years (60.2%) followed by 30.6% in the 11 to 15 year group. The lowest success rate of tip placement of only 9.2% was observed in younger children of age 1 to 5 years, which is statistically significant (P = 0.001). Of 102 incorrect placements reported, 37% were in 1 to 5 year age group versus 9.2% correct tip placements. The most common unsatisfactory placements were either in the ipsilateral internal jugular vein (N = 38, 37.2%) or in the ipsilateral subclavian vein (N = 27, 26.4%). In 10 patients the catheter crossed over to the opposite subclavian vein, in 16 patients the catheter tips were found in the axillary vein, and in 10 patients each the catheter tip was observed in right atrium and right ventricle. No major complication during and following CVC was observed. To conclude, CVC using single orifice catheter through arm veins in pediatric patients is easy to perform, but the proper catheter tip placement is highly unreliable, particularly in younger children 1 to 5 years of age.

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.

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.

Locked-in syndrome during stellate ganglion block

Intra-arterial injection of a local anaesthetic during stellate ganglion blockade may cause life-threatening complications. The usual complications are apnoea, unconsciousness and seizures. However, occasionally an unusual complication, ‘locked-in’ syndrome, has also been reported. In this syndrome the patients remain conscious despite their inability to move, breathe or speak. Here we describe a patient who developed features akin to the locked-in syndrome along with severe hypotension and bradycardia, after an injection of only 2 ml of lignocaine during a stellate ganglion block.

Effect of cerebrospinal fluid return on success rate of percutaneous retrogasserian glycerol rhizotomy

Background and Objective Trigeminal neuralgia is a painful syndrome, which has been commonly treated with percutaneous retrogasserian glycerol rhizotomy (PRGR). This study was performed to evaluate the effect of cerebrospinal fluid (CSF) return on the success rate of PRGR. Methods In this retrospective, nonrandomized, observational case series, 100 cases underwent 140 PRGRs under fluoroscopic guidance and were followed up for 6 to 36 months. The results were compared in the presence or absence of CSF return before PRGR. Results The PRGR was successful in 115 procedures (82.1%). CSF return was present in 84 procedures (60%) and, among these, 76 PRGRs (90.5%) produced pain relief. More than 1 year of pain relief without medications was present in 60 of 84 procedures (71.4%). CSF return before PRGR was absent in 56 procedures (40%) and success resulted in 39 procedures (69.6%). Pain relief for more than 1 year without medications was present in 19 procedures (33.9%). The success rate and duration of pain relief was greater in the presence of CSF return compared with absence of CSF return (P ≤ .005). The incidence of complications such as facial dysesthesia (40%), corneal anesthesia (2.8%), herpes simplex (3.5%), and nonbacterial meningitis (0.7%) was not significantly different in 2 groups (P > .05). Conclusion The presence of CSF is an important factor in determining the success rate and duration of pain relief of PRGR.

Anaesthesia for awake craniotomy: A retrospective study of 54 cases.

Background and Aims: The anaesthetic challenge of awake craniotomy is to maintain adequate sedation, analgesia, respiratory and haemodynamic stability in an awake patient who should be able to co-operate during intraoperative neurological assessment. The current literature, sharing the experience on awake craniotomy, in Indian context, is minimal. Hence, we carried out a retrospective study with the aim to review and analyse the anaesthetic management and perioperative complications in patients undergoing awake craniotomy, at our centre. Methods: Medical records of 54 patients who underwent awake craniotomy for intracranial lesions over a period of 10 years were reviewed, retrospectively. Data regarding anaesthetic management, intraoperative complications and post-operative course were recorded. Results: Propofol (81.5%) and dexmedetomidine (18.5%) were the main agents used for providing conscious sedation to facilitate awake craniotomy. Hypertension (16.7%) was the most commonly encountered complication during intraoperative period, followed by seizures (9.3%), desaturation (7.4%), tight brain (7.4%), and shivering (5.6%). The procedure had to be converted to general anaesthesia in one of patients owing to refractory brain bulge. The incidence of respiratory and haemodynamic complications were comparable in the both groups (P > 0.05). There was less incidence of intraoperative seizures in patients who received propofol (P = 0.03). In post-operative period, 20% of patients developed new motor deficit. Mean intensive care unit stay was 2.8 ± 1.9 day (1-14 days) and mean hospital stay was 7.0 ± 5.0 day (3-30 days). Conclusions: ′Conscious sedation′ was the technique of choice for awake craniotomy, at our institute. Fentanyl, propofol, and dexmedetomidine were the main agents used for this purpose. Patients receiving propofol had less incidence of intraoperative seizure. Appropriate selection of patients, understanding the procedure of surgery, and judicious use of sedatives or anaesthetic agents are key to the success for awake craniotomy as a procedure.

Metformin-associated lactic acidosis following contrast media-induced nephrotoxicity

Metformin-associated lactic acidosis following contrast media-induced nephrotoxicity V. Jain;D. Sharma;H. Prabhakar;H. Dash; European Journal of Anaesthesiology

Cardiorespiratory arrest during trigeminal rhizolysis.

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A comparative study between preoperative and postoperative pulmonary functions and diaphragmatic movements in congenital craniovertebral junction anomalies.

Respiratory dysfunctions in patients with craniovertebral junction (CVJ) anomalies may occur due to compression of brainstem affecting the respiratory centers, and weakening of the muscles of respiration. We assessed pulmonary functions [forced vital capacity (FVC), forced expiratory volume in first second (FEV1), maximum mid-expiratory flow rate (FEF25%-75%), FEV1%], mouth pressures (maximum inspiratory pressure, maximum expiratory pressure), and diaphragmatic movements in 30 patients of CVJ anomalies and compared them with their mean predictive values. These parameters were also assessed in the postoperative period. It was found that the mean values of FVC, FEV1, and FEF25%-75% were significantly lower (P<0.001) than their mean predictive values (2.4+/-0.8 L, 2.0+/-0.7 L, 2.5+/-0.9 L vs. 3.7+/-0.9 L, 3.2+/-0.7 L, and 3.4+/-0.7 L, respectively). In the postoperative period there was significant reduction (P<0.05) in all these parameters (2.2+/-0.8 L, 1.7+/-0.7 L, and 2.1+/-0.8 L, respectively). The postoperative FEV1% was 78.8% compared with the preoperative value of 85.7%. A restrictive pattern of lung disease was observed which persisted in the postoperative period. The postoperative maximum inspiratory pressure and maximum expiratory pressure were comparable to their preoperative values (47.9+/-19.6 and 47.0+/-16.7 cmH2O vs. 42.6+/-17.3 and 43.9+/-18.2 cmH2O, respectively). Similarly, the diaphragmatic movements were also comparable to the preoperative values, both during quiet and deep breathing (13.7+/-3.9 and 38.0+/-9.3 mm vs. 13.8+/-3.9 and 39.0+/-9.1 mm, respectively). There was no improvement of pulmonary functions in the early postoperative period. However, a long-term follow-up is needed to determine subsequent changes of these parameters.