Local or Spinal Anesthesia in Acute Knee Surgery

The aim of the study was to assess the efficacy, safety and complications of two anesthetic techniques including local and spinal anesthesia. A total of 436 patients received local (LA group=250) or spinal (SA group=186) anesthesia during a year period. SA group received 0.5% Bupivacaine 5 mg/mL. LA group received portal injection (5 mL lidocaine 2% with adrenaline) and intra-articular injection into the knee (10 mL lidocaine 2% with adrenaline). The following parameters were assessed: intraoperative pain (10 cm VAS: 0=no pain, 10=extreme pain), surgical operating conditions, patient satisfaction score (1=very satisfied, 4=very unsatisfied), postoperative analgesia, and time to discharge. In LA group, 97.6% (244/250) of patients experienced no pain throughout the procedure. Only six (2.4%) patients required conversion to general anesthesia. In SA group, two patients required conversion to general anesthesia. In both groups, 93.6% of patients were either satisfied or very satisfied with their anesthesia. The need of postoperative analgesics was higher in SA compared with LA group (p=0.001). The mean postoperative stay was significantly shorter in LA than in SA group (p=0.001). Ninety-four percent of LA and only 68% of SA patients were discharged from the hospital within 2 hours of the procedure. The rate of complications differed significantly between LA and SA groups (p=0.037). Outpatient arthroscopy of the knee under local anesthesia is a simple, reliable, and safe alternative to spinal anesthesia, for patients in whom intraarticular disorders requiring diagnostic arthroscopy and arthroscopic surgery

The effect of injection speed on haemodynamic changes immediate after lidocaine/adrenaline infiltration of nasal submucosa under general anaesthesia

Background and Purpose: Substantial systemic absorption after adrenaline-containing local anaesthetic infiltration can cause transitional changes in heart rate and arterial blood pressure in humans even during general anaesthesia. The aim of this study was to determine the effect of injection speed of local infiltration of adrenaline- containing lidocaine solution on transitional haemodynamic changes during local infiltration of nasal submucosa under general anaesthesia. Patients and Methods: A retrospective, comparative, non-randomised, open study on 1–2 ASA physical status 83 patients, aged 18 to 81 years, scheduled for septoplasty, septorhinoplasty, classical or functional endoscopic sinus surgery was performed. All patients received the submucosal infiltration of 2%lidocaine containing adrenaline solution (2ml) plus adrenaline (0.025 mg) plus plain 2% lidocaine solution (5ml) before surgical incision. Two different infiltration techniques were identified: fast infiltration (Group F, n=40) and slower, incremental infiltation (Group S, n=43). Heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and mean arterial pressure (MAP) were recorded before, five minutes after and ten minutes after infiltration. Results: There was no significant difference in HR, SAP,DAP nor MAP between the F group and the S group. There was significant decrease of HR (p=0.006), SAP (p=0.018), DAP (p=0.029), and MAP (p=0.010) at 10 minutes point within the S group compared to baseline. There was significant decrease of HR (p=0.04) at the 10 minutes point within the F group compared to baseline. Conclusions: This study did not confimed that the speed of injection of lidocaine with adrenaline made any effect on haemodynamic changes during local infiltration of nasal submucosa.However it confirmed that lidocaine with adrenaline induced a decrease of blood pressure

The effect of injection speed on haemodynamic changes immediate after lidocaine/adrenaline infiltration of nasal submucosa under general anaesthesia

Background and Purpose: Substantial systemic absorption after adrenaline-containing local anaesthetic infiltration can cause transitional changes in heart rate and arterial blood pressure in humans even during general anaesthesia. The aim of this study was to determine the effect of injection speed of local infiltration of adrenaline- containing lidocaine solution on transitional haemodynamic changes during local infiltration of nasal submucosa under general anaesthesia. Patients and Methods: A retrospective, comparative, non-randomised, open study on 1–2 ASA physical status 83 patients, aged 18 to 81 years, scheduled for septoplasty, septorhinoplasty, classical or functional endoscopic sinus surgery was performed. All patients received the submucosal infiltration of 2%lidocaine containing adrenaline solution (2ml) plus adrenaline (0.025 mg) plus plain 2% lidocaine solution (5ml) before surgical incision. Two different infiltration techniques were identified: fast infiltration (Group F, n=40) and slower, incremental infiltation (Group S, n=43). Heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and mean arterial pressure (MAP) were recorded before, five minutes after and ten minutes after infiltration. Results: There was no significant difference in HR, SAP,DAP nor MAP between the F group and the S group. There was significant decrease of HR (p=0.006), SAP (p=0.018), DAP (p=0.029), and MAP (p=0.010) at 10 minutes point within the S group compared to baseline. There was significant decrease of HR (p=0.04) at the 10 minutes point within the F group compared to baseline. Conclusions: This study did not confimed that the speed of injection of lidocaine with adrenaline made any effect on haemodynamic changes during local infiltration of nasal submucosa.However it confirmed that lidocaine with adrenaline induced a decrease of blood pressure

Local or spinal anesthesia in acute knee surgery [Bol pri kirurškoj artroskopiji koljena kod lokalne versus spinalne anestezije]

The aim of the study was to assess the efficacy, safety and complications of two anesthetic techniques including local and spinal anesthesia. A total of 436 patients received local (LA group=250) or spinal (SA group=186) anesthesia during a year period. SA group received 0.5% Bupivacaine 5 mg/mL. LA group received portal injection (5 mL lidocaine 2% with adrenaline) and intra-articular injection into the knee (10 mL lidocaine 2% with adrenaline). The following parameters were assessed: intraoperative pain (10 cm VAS: 0=no pain, 10=extreme pain), surgical operating conditions, patient satisfaction score (1=very satisfied, 4=very unsatisfied), postoperative analgesia, and time to discharge. In LA group, 97.6% (244/250) of patients experienced no pain throughout the procedure. Only six (2.4%) patients required conversion to general anesthesia. In SA group, two patients required conversion to general anesthesia. In both groups, 93.6% of patients were either satisfied or very satisfied with their anesthesia. The need of postoperative analgesics was higher in SA compared with LA group (p=0.001). The mean postoperative stay was significantly shorter in LA than in SA group (p=0.001). Ninety-four percent of LA and only 68% of SA patients were discharged from the hospital within 2 hours of the procedure. The rate of complications differed significantly between LA and SA groups (p=0.037). Outpatient arthroscopy of the knee under local anesthesia is a simple, reliable, and safe alternative to spinal anesthesia, for patients in whom intraarticular disorders requiring diagnostic arthroscopy and arthroscopic surgery

Theoretical analysis of the low-voltage cascade electro-osmotic pump

, on their low-voltage cascade electro-osmotic pump are analyzed using two different theoretical approaches. One is the semi-analytical equivalent circuit theory involving hydraulic resistances, pressures, and flow rates. The other is a full numerical simulation using computational fluid dynamics. These two approaches give the same results, and they are in good qualitative agreement with the published data. However, our theoretical results deviate quantitatively from the experiments. The reason for this discrepancy is discussed.

Electrohydrodynamic (In)Stability of Microfluidic Channel Flows: Analytical Expressions in the Limit of Small Reynolds Number

We study electrohydrodynamic (EHD) linear (in)stability of microfluidic channel flows, i.e., the stability of interface between two shearing viscous (perfect) dielectrics exposed to an electric field in large aspect ratio microchannels. We then apply our results to particular microfluidic systems known as two-liquid electroosmotic (EO) pumps. Our novel results are detailed analytical expressions for the growth rate of two-dimensional EHD modes in Couette–Poiseuille flows in the limit of small Reynolds number (R); the expansions to both zeroth and first order in R are considered. The growth rates are complicated functions of viscosity-, height-, density-, and dielectric-constant ratio, as well as of wavenumbers and voltages. To make the results useful to experimentalists, e.g., for voltage-control EO pump operations, we also derive equations for the impending voltages of the neutral stability curves that divide stable from unstable regions in voltage–wavenumber stability diagrams. The voltage equations and the stability diagrams are given for all wavenumbers. We finally outline the flow regimes in which our first-order-R voltage corrections could potentially be experimentally measured. Our work gives insight into the coupling mechanism between electric field and shear flow in parallel-planes channel flows, correcting an analogous EHD expansion to small R from the literature. We also revisit the case of pure shear instability, when the first-order-R voltage correction equals zero, and replace the renowned instability mechanism due to viscosity stratification at small R with the mechanism due to discontinuity in the slope of the unperturbed velocity profile