Effect of Single Dose Pre-induction Dexmedetomidine on Anaesthetic Requirement and Pain Profile in Orthopaedic Surgery: A Placebo-controlled Double Blind Randomised Controlled Trial

@#Introduction: Dexmedetomidine, a selective α2 -adrenoreceptor agonist is an important adjuvant to general anaesthetic practice in view of its potent sedative, anaesthetic-sparing and analgesic effects. We investigated the effect of a single dose pre – induction dexmedetomidine on the anaesthetic requirement during surgery and pain profile. Methods: 60 patients who were ASA I - II and planned for orthopaedic procedures under general anaesthesia were recruited. Patients were randomized into 2 groups: Group D received intravenous (IV) dexmedetomidine 1 µg/ kg (n=30) preoperatively or Group P received normal saline (n=30) instead. Both groups were induced with standardised IV induction agents and anaesthesia maintained with Sevoflurane, titrated using the bispectral index scale. The expired fraction of sevoflurane and haemodynamic parameters were recorded at 5-minute intervals intraoperatively. Postoperatively, postoperative pain score (VAS) was documented at 30 minutes recovery. Results: Our study showed a 27.8% reduction in the intraoperative expired fraction of sevoflurane requirement in group D versus 11.5% reduction in Group P (p < 0.001) and a lower mean heart rate in Group D as compared to Group P [mean (CI): 69.20 (64.03, 74.37) versus 82.00 (72.12, 91.87) per minute, p = 0.00]. The mean (SD) VAS for 30 minutes postoperative pain was significantly lower in group D when compared to group P [1.507(0.275) vs 2.209(0.403), p = 0.00]. Conclusion: This study has shown that a single dose of pre-induction dexmedetomidine was able to significantly reduce anaesthetic requirement of sevoflurane and mean heart rate intraoperatively and postoperative pain.

Comparison of the Effects of Dexmedetomidine on the Induction of Anaesthesia Using Marsh and Schnider Pharmacokinetic Models of Propofol Target-Controlled Infusion

Background: The study aimed to determine the effects of dexmedetomidine on the induction of anaesthesia using different models (Marsh and Schnider) of propofol targetcontrolled infusion (TCI). Methods: Sixty-four patients aged 18–60 years, American Society of Anaesthesiologists (ASA) class I-II who underwent elective surgery were randomised to a Marsh group (n = 32) or Schnider group (n = 32). All the patients received a 1 μg/kg loading dose of dexmedetomidine, followed by TCI anaesthesia with remifentanil at 2 ng/mL. After the effect-site concentration (Ce) of remifentanil reached 2 ng/mL, propofol TCI induction was started. Anaesthesia induction commenced in the Marsh group at a target plasma concentration (Cpt) of 2 μg/mL, whereas it started in the Schnider group at a target effect-site concentration (Cet) of 2 μg/mL. If induction was delayed after 3 min, the target concentration (Ct) was gradually increased to 0.5 μg/mL every 30 sec until successful induction. The Ct at successful induction, induction time, Ce at successful induction and haemodynamic parameters were recorded. Results: The Ct for successful induction in the Schnider group was significantly lower than in the Marsh group (3.48 [0.90] versus 4.02 [0.67] μg/mL; P = 0.01). The induction time was also shorter in the Schnider group as compared with the Marsh group (134.96 [50.91] versus 161.59 [39.64]) sec; P = 0.02). There were no significant differences in haemodynamic parameters and Ce at successful induction. Conclusion: In the between-group comparison, dexmedetomidine reduced the Ct requirement for induction and shortened the induction time in the Schnider group. The inclusion of baseline groups without dexmedetomidine in a four-arm comparison of the two models would enhance the validity of the findings.

The First Awake Clipping of a Brain Aneurysm in Malaysia and in ASEAN: Achieving International Standards

World-renowned neurosurgeon, Professor Saleem Abdulrauf, has been featured in several medical journals for his successful “Awake Brain Aneurysm Surgery”. Regarded as a “world first”, this surgery, involves clipping un-ruptured brain aneurysms while patients are awake. Only one or two neurosurgery centres worldwide are capable of this. Performing the surgery while the patient is awake lowers risks of brain ischemia with neurological deficits and ventilator associated morbidities. The technique has been viewed as the start of a new era in brain surgery. Physicians from the Universiti Sains Malaysia (USM) School of Medical Sciences, at the Health Campus in Kelantan, headed by Professor Dr Zamzuri Idris (neurosurgeon) and Dr Wan Mohd Nazaruddin Wan Hassan (neuroanaesthetist), recently performed a similar procedure, the first such surgery in Malaysia and Southeast Asia. The USM team can therefore be considered to be among the first few to have done this brain surgery and achieved successful patient outcomes.

Balanced Fluid Versus Saline-Based Fluid in Post-operative Severe Traumatic Brain Injury Patients: Acid Base and Electrolytes Assessment

Background: Normal saline (NS) is a common fluid of choice in neurosurgery and neurointensive care unit (ICU), but it does not contain other electrolytes and has the potential to cause hyperchloremic metabolic acidosis with prolonged infusion. These problems may be reduced with the availability of balanced fluid (BF), which becomes a more physiological isotonic solution with the presence of complete electrolyte content. This study aimed to compare the changes in electrolytes and acid–base between NS and BF (Sterofundin® ISO) therapy for post-operative severe traumatic brain injury (TBI) patients in neuro-ICU. Methods: Sixty-six severe TBI patients who required emergency craniotomy or craniectomy and were planned for post-operative ventilation were randomised into NS (n = 33) and BF therapy groups (n = 33). The calculation of maintenance fluid given was based on the Holliday-Segar method. The electrolytes and acid–base parameters were assessed at an 8 h interval for 24 h. The data were analysed using repeated measures ANOVA. Results: The NS group showed a significant lower base excess (-3.20 versus -1.35, P = 0.049), lower bicarbonate level (22.03 versus 23.48 mmol/L, P = 0.031), and more hyperchloremia (115.12 versus 111.74 mmol/L, P < 0.001) and hypokalemia (3.36 versus 3.70 mmol/L, P < 0.001) than the BF group at 24 h of therapy. The BF group showed a significantly higher level of calcium (1.97 versus 1.79 mmol/L, P = 0.003) and magnesium (0.94 versus 0.80 mmol/L, P < 0.001) than the NS group at 24 h of fluid therapy. No significant differences were found in pH, pCO2, lactate, and sodium level. Conclusion: BF therapy showed better effects in maintaining higher electrolyte parameters and reducing the trend toward hyperchloremic metabolic acidosis than the NS therapy during prolonged fluid therapy for postoperative TBI patients.

Target-controlled Infusion Propofol Versus Sevoflurane Anaesthesia for Emergency Traumatic Brain Surgery: Comparison of the Outcomes

Background: The choice of anaesthetic techniques is important for the outcome of traumatic brain injury (TBI) emergency surgery. The objective of this study was to compare patient outcomes for target-controlled infusion (TCI) of propofol and sevoflurane anaesthesia. Methods: A total of 110 severe TBI patients, aged 18–60, who underwent emergency brain surgery were randomised into Group T (TCI) (n = 55) and Group S (sevoflurane) (n = 55). Anaesthesia was maintained in Group T with propofol target plasma concentration of 3–6 μg/mL and in Group S with minimum alveolar concentration (MAC) of sevoflurane 1.0–1.5. Both groups received TCI remifentanil 2–8 ng/mL for analgesia. After the surgery, patients were managed in the intensive care unit and were followed up until discharge for the outcome parameters. Results: Demographic characteristics were comparable in both groups. Differences in Glasgow Outcome Scale (GOS) score at discharge were not significant between Group T and Group S (P = 0.25): the percentages of mortality (GOS 1) [27.3% versus 16.4%], vegetative and severe disability (GOS 2–3) [29.1% versus 41.8%] and good outcome (GOS 4–5) [43.6% versus 41.8%] were comparable in both groups. There were no significant differences in other outcome parameters. Conclusion: TCI propofol and sevoflurane anaesthesia were comparable in the outcomes of TBI patients after emergency surgery.

Life-Threatening Dyskalaemia after Barbiturate Coma Therapy: The Strategy of Management

Barbiturate coma therapy (BCT) is a treatment option that is used for refractory intracranial hypertension after all other options have been exhausted. Although BCT is a brain protection treatment, it also has several side effects such as hypotension, hepatic dysfunction, renal dysfunction, respiratory complications and electrolyte imbalances. One less concerning but potentially life-threatening complication of BCT is dyskalaemia. This complication could present as severe refractory hypokalaemia during the therapy with subsequent rebound hyperkalaemia after cessation of the therapy. Judicious potassium replacement during severe refractory hypokalaemia and gradual cessation of the therapy to prevent rebound hyperkalaemia are recommended strategies to deal with this complication, based on previous case series and reports. In this case report, we show that these strategies were applicable in improving severe hypokalaemia and preventing sudden, life-threatening rebound hyperkalaemia. However, even with use of these strategies, BCT patients could still present with mild, asymptomatic hyperkalaemia.

The History of Awake Craniotomy in Hospital Universiti Sains Malaysia

Awake craniotomy is a brain surgery performed on awake patients and is indicated for certain intracranial pathologies. These include procedures that require an awake patient for electrocorticographic mapping or precise electrophysiological recordings, resection of lesions located close to or in the motor and speech of the brain, or minor intracranial procedures that aim to avoid general anaesthesia for faster recovery and earlier discharge. This type of brain surgery is quite new and has only recently begun to be performed in a few neurosurgical centres in Malaysia. The success of the surgery requires exceptional teamwork from the neurosurgeon, neuroanaesthesiologist, and neurologist. The aim of this article is to briefly describe the history of awake craniotomy procedures at our institution.