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.

Effects of retractor application on cuff pressure and vocal cord function in patients undergoing anterior cervical discectomy and fusion.

Anterior cervical discectomy and fusion is a commonly performed procedure for prolapse of cervical intervertebral disc. It involves retraction of soft tissue of neck for adequate exposure of anterior spinal canal. Increased cuff pressure with retractor application may affect the postoperative vocal cord function. Cuff pressures of tracheal tube were measured continuously in 37 patients using air-filled pressure transducer connected to the pilot balloon. Changes of pressure from baseline values were noted after application of cervical retractor. At the end of procedure, vocal cord movement was observed using fibreoptic bronchoscope. Significant increase in cuff pressure (168% of baseline values) and airway pressure of tracheal tube during cervical retraction was observed. The vocal cord function was assessed using fibreoptic laryngoscope. One patient developed right vocal cord palsy (2.7%) and two patients had postoperative hoarseness of voice (5.4%). All these complications improved over a period of time. It is suggested that the cuff of tracheal tube should be inflated to achieve 'just seal', with adequate cuff pressure monitoring. Intermittent release of cervical retraction may help to prevent laryngeal morbidities.

Effects of phenytoin therapy on bispectral index and haemodynamic changes following induction and tracheal intubation.

SUMMARY: 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.