A Comparison of Soda Lime (Intersurgical) with Amsorb® plus: The Cost Implications

This was a prospective study comparing the cost implications between two carbon dioxide (CO2) absorbers, soda lime (Intersurgical) and AMSORB® PLUS. The study was conducted over two 4-week periods in two dedicated operating theatres using Datex Ohmeda Aestiva/5 anaesthetic machines. AMSORB® PLUS was used during the first four weeks and soda lime (Intersurgical) the following four weeks. General anaesthesia was administered as routinely done but fresh gas flow (FGF) during the maintenance phase was limited to a maximum flow of 2 L/min. The CO2 absorber was only changed when there was evidence of exhaustion. Total duration of anaesthesia, sevoflurane (bottles) and CO2 absorber (kg) consumption, and amount of waste product (kg) was calculated at the end of each study period. The total cost of delivering general anaesthesia was lower in the AMSORB® PLUS group, RM82.40 (USD19.89)/hour versus the soda lime group, RM91.50 (USD 22.09)/hour (p=0.17), which translates to a 10% reduction in cost per hour. Reduction in sevoflurane consumption in the AMSORB® PLUS compared to the soda lime group was also not statistically significant (p=0.22). The only significant finding was the reduction in CO2 absorber consumption in the AMSORB® PLUS group as compared to soda lime group (p=0.001). In conclusion, AMSORB® PLUS consumption was significantly reduced compared to that of soda lime. However, the use of AMSORB® PLUS did not significantly reduce sevoflurane consumption nor the total cost of delivering general anaesthesia. Given the superior safety profile, AMSORB® PLUS may be a suitable, cost-effective alternative to soda lime in the daily practice of anaesthesia.

Sedation with Dexmedetomidine versus Propofol during Regional Anaesthesia: Comparing Haemodynamic Parameters, Respiratory Rates and Offset Times

This study aimed to compare dexmedetomidine and propofol, in terms of haemodynamic parameters, respiratory rates and offset times, when used for sedation in patients undergoing elective orthopaedic and surgical procedures under regional anaesthesia. This was a prospective, randomised, single-blind study where 88 patients were recruited. Patients were randomised into two groups to receive either dexmedetomidine or propofol infusion. Central neuraxial blockade (spinal, epidural or combined spinal epidural) was performed. After ensuring an adequate block and stable haemodynamic parameters, dexmedetomidine was infused 15 minutes later at 0.4 μg/kg/hr, and propofol, at a target concentration of 2.5 μg/ml. Both drugs were titrated to achieve a bispectral index score of 70 before surgery commenced. Sedation level was monitored using the bispectral index score and assessed by the Observer Assessment of Alertness Scale score. Drug infusion was adjusted to maintain bispectral index scores ranging between 70-80 during surgery. Both groups showed reductions in mean arterial pressure and heart rate from baseline readings throughout the infusion time. However there was no significant reduction in the first 15 minutes from baseline (p > 0.05). Haemodynamic parameters and respiratory rate between both groups were not significantly different (p > 0.05). No patient demonstrated significant respiratory depression or SpO2 ≤ 95%. Offset times were also not significantly different between both groups (p = 0.594). There were no significant differences in haemodynamic parameters, respiratory rates and offset times between dexmedetomidine and propofol used for sedation in patients undergoing elective orthopaedic and surgical procedures under regional anaesthesia.

Comparison between the Use of LMA™ and SLIPA™ in Patients Undergoing Minor Surgeries

Supraglottic airway devices have been used as safe alternatives to endotracheal intubation in appropriate types of surgery. This was a prospective, randomised, single blind study comparing the use of LMA™ and SLIPA™ in terms of ease of insertion, haemodynamic changes and occurrence of adverse effects (e.g. blood stains on the device upon removal and sore throat). A total of 62 ASA I or II patients, aged between 18 to 70 years were recruited for this study. Patients were randomised into two groups; LMA™ and SLIPA™ group. Following induction of anaesthesia, an appropriate sized LMA™ or SLIPA™ was inserted after ensuring adequate depth of anaesthesia. Anaesthesia was maintained with oxygen, nitrous oxide and sevoflurane. The ease of insertion was graded and haemodynamic changes were recorded at 2 minute intervals up to 10 minutes after insertion of the airway devices. The presence of blood stains upon airway device removal at the end of surgery and incidence of sore throat was also recorded. No difficult insertion was experienced in either of these devices. Insertion was either easy [LMA™ 87.1% versus SLIPA™ 80.6% (p = 0.49)] or moderate [LMA™ 12.9% versus SLIPA™ 19.4% (p = 0.16)]. Throughout the study period, the haemodynamic changes that occurred in both groups were not statistically different. Traces of blood were noted on the surface of the device in 9.7% of patients in the SLIPA™ group versus 6.5% of patients in the LMA™ group. The incidence of sore throat was recorded in 12.9% versus 19.4% of patients in the SLIPA™ and the LMA™ groups respectively. These findings were not statistically significant. In conclusion, this study showed no significant differences between the use of LMA™ and SLIPA™ in terms of ease of insertion, haemodynamic changes and adverse effects in patients undergoing minor surgical procedures.

Estimation of Endotracheal Tube Cuff Pressure among Anaesthesia Providers Does Experience Matter?

The endotracheal tube (ETT) cuff pressure is usually estimated and assumed to be within the appropriate range. However, the estimation of cuff pressure may be influenced by the various estimation techniques used by anaesthesia providers and their different experience level. The main aim of this study was to observe the correlation between the experience of the anaesthesia providers and their ability to estimate endotracheal cuff pressure in a correct manner. One hundred anaesthesia providers were classified into three different groups based on their months of anaesthetic experience: Group I (< 36 months), Group II (36 to 59 months) and Group III (≥ 60 months). Following intubation, the ETT cuff was inflated by the anaesthetic nurse and ETT placement verified by the anaesthesia provider. Using the pilot balloon palpation technique (PBPT), the cuff pressure was estimated to be within the appropriate pressure range, over or under-inflated. The necessary adjustments were made if needed after measurement with a VBM™ Manometer Pressure Gauge. More number of months of anaesthesia experience was not associated with a greater ability to correctly estimate the ETT cuff pressure. However, this correlation was poor (r = - 0.177). The pilot balloon palpation technique was found to be only moderately sensitive (76.5%) but poorly specific (42.9%) for correct estimation of the ETT cuff pressure, whereby PPV and NPV were 58.2% and 63.6%, respectively. The technique was 50% (95% CI 24.04 - 75.95) sensitive while correctly estimating the under-inflated cuff and 60% (95%CI 13.25-37.81) sensitive to correctly estimating the over-inflated cuff. The results depict that the experience of anaesthesia providers did not correlate with the ability to correctly estimate the ETT cuff pressure.