ABSTRACT
BACKGROUND AND AIMS: Sound knowledge about effect site concentration (Ce) of propofol aids in smooth induction, maintenance and early recovery. We studied the correlation between Ce of propofol at loss of response to verbal command and recovery concentration using target-controlled infusion (TCI) in Indian patients who underwent spine surgeries. METHODS: Ninety patients undergoing spine surgeries were included. Total intravenous anaesthesia (TIVA) technique with TCI for propofol using modified Marsh model was used. Entropy and neuromuscular transmission were used. Ce at induction and recovery and the corresponding state entropy (SE) values were noted. RESULTS: The mean propofol Ce and SE at induction were 2.34 ± 0.24 µg/ml and 52 ± 8, respectively. The mean propofol Ce and SE at recovery were 1.02 ± 0.22 µg/ml and 86.80 ± 2.86, respectively. The Ce at recovery was approximately 50% of the induction value. The correlation coefficient 'r' between Ce at induction and recovery was 0.56. The mean infusion dose of propofol during the maintenance period was 81 ± 14.33 µg/kg/min. The average induction dose of propofol was 1.17 ± 0.2 mg/kg. CONCLUSION: There is a positive correlation between Ce at induction and recovery. Ce for recovery may have to be set at a lower level during TCI-TIVA and appropriately infusion should be stopped for early recovery. The induction and maintenance doses of propofol are lower than the recommended doses. Data emphasise the need for pharmacokinetic model based on our population characteristics.
ABSTRACT
BACKGROUND AND AIMS: Patients with intracranial tumour are usually on anticonvulsants. Patients on phenytoin therapy demonstrate rapid metabolism of nondepolarising muscle relaxants secondary to enzyme induction. Infusion dose requirement of rocuronium in such patients has been sparingly studied. We studied the continuous infusion dose requirement of rocuronium bromide in patients on phenytoin therapy and its correlation with serum levels of phenytoin. METHODS: Seventy-five patients scheduled for supratentorial tumour surgery were included in the study. Patients not on phenytoin were taken as control. The primary outcome variable studied was the infusion dose requirement of rocuronium in patients on phenytoin. Based on pre-operative serum phenytoin levels, study group patients were divided into two groups: sub-therapeutic level group (phenytoin level <10 µg/mL) and therapeutic level group (phenytoin level >10 µg/mL). Following anaesthesia induction, rocuronium bromide 0.6 mg/kg was administered to achieve tracheal intubation. Rocuronium infusion was titrated to maintain zero response on the train-of-four response. RESULTS: Demographic data were comparable. Patients receiving phenytoin required higher infusion dose compared to the control group (0.429 ± 0.2 mg/kg/h vs. 0.265 ± 0.15 mg/kg/h, P < 0.001). The serum phenytoin level had no correlation to infusion dose requirement of rocuronium (0.429 ± 0.205 mg/kg/h vs. 0.429 ± 0.265 mg/kg/h (P = 0.815). The recovery was faster in the phenytoin group compared to the control group. Haowever, it was not clinically significant. CONCLUSION: The infusion dose requirement of rocuronium bromide in patients on phenytoin is higher and the serum levels of phenytoin does not influence the dose required.
ABSTRACT
BACKGROUND AND AIMS: Pre-operative investigations are performed before any surgical intervention under anaesthesia. Many are considered as routine. However, there are no clear guidelines regarding these in India. We aim to look at the relevance of the laboratory investigations ordered routinely and their cost implications compared with the National Institute of Clinical Excellence (NICE) guidelines. METHODS: This prospective study was carried out at a tertiary care hospital. A total of 163 patients scheduled for elective surgical procedures were included in this study. Neither the surgeons nor anaesthesiologists involved in the case were aware of the study. The laboratory investigations of the patients who underwent surgery were noted. All values were categorised as normal or abnormal and they were assessed as indicated or unindicated based on NICE guidelines. RESULTS: One hundred and sixty-three patients were subjected to a total of 984 tests. Forty three patients (26%) were subjected to tests as per NICE guidelines. Of the 984 tests, 515 tests were unindicated (52%). Out of the 515 unindicated tests, 7 (1.3%) were abnormal. None of these seven tests required any intervention or change of anaesthetic plan. The most common unindicated tests done were cardiac echocardiography and chest X-ray (92.5% and 93% respectively). The additional cost incurred towards unindicated tests was 63% of the total cost for the tests. CONCLUSION: Pre-operative laboratory investigations add to cost significantly. Patient premorbid conditions and surgical grade should guide the clinician to request for the relevant laboratory tests.
