Anaesthesia and intensive care
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Anaesth Intensive Care · Mar 2019
Randomized Controlled TrialAdding low concentrations of clonidine to ropivacaine for transversus abdominis plane blocks does not reduce plasma ropivacaine levels, suggesting a lack of vasoconstrictor effect.
Clonidine has been used successfully to prolong the duration of action of local anaesthetics in peripheral nerve blocks, but its mechanism of action in this setting remains unclear. Some studies suggest that clonidine exerts a vasoconstrictor effect, limiting the washout of local anaesthetic from its site of deposition. We investigated this potential vasoconstrictor effect, using plasma ropivacaine concentrations as a surrogate measure of vasoconstriction, in patients who received transversus abdominis plane (TAP) blocks with and without clonidine. ⋯ These findings indicate that clonidine at a concentration of 1.35 μg/mL added to ropivacaine for TAP blocks did not produce a reduction in plasma ropivacaine concentrations. This suggests a lack of vasoconstrictor effect during TAP blocks. Further studies should evaluate whether vasoconstriction occurs when clonidine is used at higher concentrations or for other blocks.
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Anaesth Intensive Care · Jan 2019
Randomized Controlled TrialA comparison of different modes of pneumatic compression on muscle tissue oxygenation: An intraparticipant, randomised, controlled volunteer study.
Intermittent pneumatic compression (IPC) to the lower limbs is widely used as a mechanical means to prevent deep vein thrombosis in hospitalised patients. Due to a theoretical concern about impairing blood flow, thromboembolic-deterrent stockings and IPC are considered contraindicated for patients with peripheral vascular diseases by some clinicians. This study assessed whether IPC would alter peripheral limb muscle tissue oxygenation (StO2), and whether such changes were different during 10 minutes of sequential and single-compartment compressions. ⋯ Both sequential (3.5%, 95% confidence intervals (CI) 2.7-4.2; p < 0.001) and single-compartment IPC (1.6%, 95% CI 0.4-2.8; p = 0.039) significantly increased muscle StO2 within 10 minutes compared to no compression; and the increments were higher during sequential compressions compared to during single-compartment compressions (2.1%, 95% CI 0.7-3.5; p = 0.023). This mechanistic study showed that both modes of IPC increased upper limb muscle StO2 compared to no compression, but the StO2 increments were higher with the multiple-chamber sequential compressions mode. Contrary to the theoretical concern that IPC may impair peripheral limb tissue oxygenation, our results showed that IPC actually increases oxygenation of the peripheral limb muscles, especially during the sequential compressions mode.
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Anaesth Intensive Care · Sep 2018
Randomized Controlled Trial Comparative StudyA randomised controlled trial comparing fibreoptic-guided tracheal intubation through two supraglottic devices: Ambu® AuraGain™ laryngeal mask and LMA® Fastrach™.
The Ambu®AuraGain™ laryngeal mask (LM) (Ambu A/S, Ballerup, Denmark) is one of the few readily available second-generation supraglottic airway devices (SADs) that offer a conduit for fibreoptic-guided endotracheal intubation. We aimed to compare fibreoptic intubation through this device with the LMA® (laryngeal mask airway) Fastrach™ (Teleflex Medical, Co. Westmeath, Ireland), which has been a recommended dedicated rescue device for the management of the unanticipated difficult airway. ⋯ The AuraGain LM was also quicker to insert compared to the Fastrach LMA. Similar rates of minor complications, such as sore throat and dysphonia occurred in both groups. Our study indicates that when used in patients with complete muscle relaxation and no known airway pathology, the AuraGain LM achieves better laryngeal alignment and quicker, easier and more successful fibreoptic-guided ETT intubation than the Fastrach LMA.
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Anaesth Intensive Care · Sep 2018
Randomized Controlled TrialDoes a catheter over needle system reduce infusate leak in continuous peripheral nerve blockade: a randomised controlled trial.
Continuous peripheral nerve blockade is a common technique in the analgesic management for many procedures. Leakage of local anaesthetic from around the nerve catheter insertion site can increase the chance of catheter dislodgement, risks infective complications, and could divert anaesthetic away from the nerve causing the block to fail. We conducted a randomised controlled trial to assess whether the type of nerve catheter influenced local anaesthetic leak rate. ⋯ All seven instances of inadvertent catheter dislodgement occurred in the CTN group (P=0.006). There was no statistically significant difference between groups in the proportion of patients who had adequate analgesia on day one (CON 80% versus CTN 86.5%; P=0.294) and day two postoperatively (CON 85.5% versus CTN 91.8%; P=0.369). Our findings show the overall leak rate to be very low with both catheter systems; however, the CON system may have advantages in terms of speed of use and rate of inadvertent catheter dislodgement.
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Anaesth Intensive Care · Jul 2018
Randomized Controlled TrialThe use of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) for pre-oxygenation in neurosurgical patients: a randomised controlled trial.
This study explored the use of high-flow nasal oxygen (HFNO) in both pre-oxygenation and apnoeic oxygenation in adults who were intubated following a non-rapid sequence induction. Fifty patients were randomised to receive pre-oxygenation via a standard facemask or the Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) device. After five minutes of pre-oxygenation, induction and muscle relaxant agents were given. ⋯ No complications were observed in either group. HFNO produces a higher PaO2 after pre-oxygenation and safe PaO2 during intubation. However, the subsequent fall in PaO2 and rise in PaCO2 indicates that it is not as effective as BMV in maintaining oxygenation and ventilation following neuromuscular blockade.