The Role of Dexmedetomidine as an Additive to Intravenous Regional Anesthesia: A Systematic Review and Meta-analysis.

BACKGROUND: Intravenous Regional Anesthesia (IVRA) is a reliable and cost-effective anesthetic method for minor surgical procedures to the extremities. Limitations of this block include tourniquet discomfort, short duration of anesthesia, and absence of postoperative analgesia. Dexmedetomidine has been used as an adjuvant to minimize these negative characteristics with inconclusive results. AIM: To perform a systematic review of the existing evidence on the role of dexmedetomidine as an additive to intravenous regional anesthesia in upper limb surgery. STUDY DESIGN: Systematic Review and Meta-analysis. METHODS: The databases searched were MEDLINE, Embase, PubMed, CINAHL, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials databases, and clinicaltrials. gov (1990-2019). Seven randomized controlled trials (RCTs) were included. We analyzed the duration of analgesia, onset time of sensory and motor block, intraoperative tourniquet pain scores, the incidence of tourniquet pain, need for rescue analgesia, intraoperative rescue analgesia consumption, sedation scores, postoperative pain scores, and anesthesia quality. RESULTS: Intraoperative analgesia duration (MD 11.08 min; 95% CI 5.42, 16.75; P < .0001) was longer and sensory block onset time (MD -2.10 min; 95% CI -3.345, -0.86; P = .00009) was shorter in the dexmedetomidine group. Anesthesia quality scores (MD 0.58; 95% CI 0.47, 0.70; P < .00001) and postoperative sedation scores (MD 1.03; 95% CI 0.88, 1.24; P < .00001) were significantly higher. There was a significant reduction in intraoperative rescue analgesia consumption (MD -19.70 mg; 95% CI -24.15, -15.26; P < .00001) in the dexmedetomidine group. The risk of tourniquet pain as well as postoperative pain scores were lower in favor of dexmedetomidine. The addition of dexmedetomidine to IVRA slightly increased the risk of sedation. A limitation of our study is that some of the interesting outcomes derive from a small number of RCTs. CONCLUSION: The addition of dexmedetomidine to IVRA ameliorates the block's characteristics and carries a low risk of potential side effects.

Volatiles or TIVA: Which is the standard of care for pediatric airway procedures? A pro-con discussion.

Anesthesia for pediatric airway procedures constitutes a true art form that requires training and experience. Communication between anesthetist and surgeon to establish procedure goals is essential in determining the most appropriate anesthetic management. But does the mode of anesthesia have an impact? Traditionally, inhalational anesthesia was the most common anesthesia technique used during airway surgery. Introduction of agents used for total intravenous anesthesia (TIVA) such as propofol, short-acting opioids, midazolam, and dexmedetomidine has driven change in practice. Ongoing debates abound as to the advantages and disadvantages of volatile-based anesthesia versus TIVA. This pro-con discussion examines both volatiles and TIVA, from the perspective of effectiveness, safety, cost, and environmental impact, in an endeavor to justify which technique is the best specifically for pediatric airway procedures.

Impact of timing of continuous intravenous anesthetic drug treatment on outcome in refractory status epilepticus.

BACKGROUND: Patients in refractory status epilepticus (RSE) may require treatment with continuous intravenous anesthetic drugs (cIVADs) for seizure control. The use of cIVADs, however, was recently associated with poor outcome in status epilepticus (SE), raising the question of whether cIVAD therapy should be delayed for attempts to halt seizures with repeated non-anesthetic antiepileptic drugs. In this study, we aimed to determine the impact of differences in therapeutic approaches on RSE outcome using timing of cIVAD therapy as a surrogate for treatment aggressiveness. METHODS: This was a retrospective cohort study over 14 years (n = 77) comparing patients with RSE treated with cIVADs within and after 48 h after RSE onset, and functional status at last follow-up was the primary outcome (good = return to premorbid baseline or modified Rankin Scale score of less than 3). Secondary outcomes included discharge functional status, in-hospital mortality, RSE termination, induction of burst suppression, use of thiopental, duration of RSE after initiation of cIVADs, duration of mechanical ventilation, and occurrence of super-refractory SE. Analysis was performed on the total cohort and on subgroups defined by RSE severity according to the Status Epilepticus Severity Score (STESS) and by the variables contained therein. RESULTS: Fifty-three (68.8%) patients received cIVADs within the first 48 h. Early cIVAD treatment was independently associated with good outcome (adjusted risk ratio [aRR] 3.175, 95% confidence interval [CI] 1.273-7.918; P = 0.013) as well as lower chance of both induction of burst suppression (aRR 0.661, 95% CI 0.507-0.861; P = 0.002) and use of thiopental (aRR 0.446, 95% CI 0.205-0.874; P = 0.043). RSE duration after cIVAD initiation was shorter in the early cIVAD cohort (hazard ratio 1.796, 95% CI 1.047-3.081; P = 0.033). Timing of cIVAD use did not impact the remaining secondary outcomes. Subgroup analysis revealed early cIVAD impact on the primary outcome to be driven by patients with STESS of less than 3. CONCLUSIONS: Patients with RSE treated with cIVADs may benefit from early initiation of such therapy.

Bispectral index to guide induction of anesthesia: a randomized controlled study.

BACKGROUND: It is unknown to what extent hypotension frequently observed following administration of propofol for induction of general anesthesia is caused by overdosing propofol. Unlike clinical signs, electroencephalon-based cerebral monitoring allows to detect and quantify an overdose of hypnotics. Therefore, we tested whether the use of an electroencephalon-based cerebral monitoring will cause less hypotension following induction with propofol. METHODS: Subjects were randomly assigned to a bispectral index (BIS)-guided (target range 40-60) or to a weight-related (2 mg.kg- 1) manual administration of propofol for induction of general anesthesia. The primary endpoint was the incidence of hypotension following the administration of propofol. Secondary endpoints included the degree of hypotension and correlations between BIS and drop in mean arterial pressure (MAP). Incidences were analyzed with Fisher's Exact-test. RESULTS: Of the 240 patients enrolled into this study, 235 predominantly non-geriatric (median 48 years, 25th - 75th percentile 35-61 years) patients without severe concomitant disease (88% American Society of Anesthesiology physical status 1-2) undergoing ear, nose and throat surgery, ophthalmic surgery, and dermatologic surgery were analyzed. Patients who were manually administered propofol guided by BIS (n = 120) compared to those who were given propofol by weight (n = 115) did not differ concerning the incidence of hypotension (44% vs. 45%; p = 0.87). Study groups were also similar regarding the maximal drop in MAP compared to baseline (33% vs. 30%) and the proportion of hypotensive events related to all measurements (17% vs. 19%). Final propofol induction doses in BIS group and NON-BIS group were similar (1.93 mg/kg vs. 2 mg/kg). There was no linear correlation between BIS and the drop in MAP at all times (r < 0.2 for all) except for a weak one at 6 min (r = 0.221). CONCLUSION: Results of our study suggest that a BIS-guided compared to a weight-adjusted manual administration of propofol for induction of general anesthesia in non-geriatric patients will not lower the incidence and degree of arterial hypotension. TRIAL REGISTRATION: German Registry of Clinical Trials ( DRKS00010544 ), retrospectively registered on August 4, 2016.

Anesthetic Considerations for Patients Undergoing Bronchial Thermoplasty.

Bronchial thermoplasty (BT) is a novel, Food and Drug Administration-approved nondrug treatment for patients whose asthma remains uncontrolled despite traditional pharmacotherapy. BT involves application of controlled radiofrequency energy to reduce airway smooth muscle in large- and medium-sized airways. Although BT is often performed under general anesthesia, anesthetic management strategies for BT are poorly described. We describe the anesthetic management of 7 patients who underwent 19 BT treatments in a tertiary academic medical center.

Total intravenous anaesthesia versus single-drug pharmacological antiemetic prophylaxis in adults: A systematic review and meta-analysis.

BACKGROUND: Postoperative nausea and vomiting (PONV) are among the most unfavourable anaesthetic outcomes attributed to the administration of inhaled anaesthetics. Accordingly, inhaled anaesthetics are frequently substituted by propofol when patients are at risk of PONV. As, on some occasions, inhalational anaesthesia may be favourable, the relative impact of propofol anaesthesia needs to be established based on robust data. OBJECTIVE: To compare the effectiveness of a single-drug pharmacological prophylaxis with total intravenous anaesthesia (TIVA) for prevention of PONV. DESIGN: Systematic review of randomised controlled trials with meta-analyses. DATA SOURCES: All available studies until 29 April 2015 were retrieved from MEDLINE, CENTRAL and EMBASE. ELIGIBILITY CRITERIA: Randomised controlled trials on adult patients undergoing general anaesthesia with at least one group receiving propofol-based intravenous anaesthesia without further antiemetic prophylaxis, and one group receiving inhalational anaesthesia with single-drug antiemetic prophylaxis. RESULTS: Fourteen studies involving 2051 patients were included. Compared with TIVA, after inhalational anaesthesia and single-drug antiemetic prophylaxis, there was no difference in the overall risk of PONV [relative risk (RR) 1.06, 95% confidence interval (CI) 0.85; 1.32, GRADE rating moderate], nor was there any difference in the risk of postoperative vomiting (RR 1.17, 95% CI 0.78; 1.76), need for rescue medication (RR 1.16, 95% CI 0.68; 1.99) or early PONV (RR 1.06, 95% CI 0.88; 1.27). However, TIVA was associated with an increased risk of late PONV (RR 1.41, 95% CI 1.10; 1.79, P = 0.006). Six studies investigated other side-effects associated with anaesthesia and found no differences between the two groups. Finally, there was evidence of a publication bias that included smaller studies favouring TIVA. CONCLUSION: This meta-analysis confirms the results from indirect comparisons in individual studies: instead of substituting inhalational anaesthesia with propofol-based TIVA, a similar antiemetic effect can be achieved by adding single-drug pharmacological prophylaxis to the inhalational anaesthetic. STUDY REGISTRATION: This systematic review with meta-analysis was registered at PROSPERO (www.crd.york.ac.uk/PROSPERO), study number CRD42015019571.

Target-controlled versus fractionated propofol sedation in flexible bronchoscopy: A randomized noninferiority trial.

BACKGROUND AND OBJECTIVE: Fractionated propofol administration (FPA) in flexible bronchoscopy (FB) may lead to oversedation and an increased risk of adverse events, because a stable plasma concentration of propofol is not maintainable. The purpose of this randomized noninferiority trial was to evaluate whether target-controlled infusion (TCI) of propofol is noninferior to FPA in terms of safety in FB. METHODS: Coprimary outcomes were the mean lowest arterial oxygen saturation (SpO2 ) during FB and the number of propofol dose adjustments in relation to procedure duration. Secondary outcomes were the number of occasions with SpO2 < 90% and/or oxygen desaturations of >4% from baseline, number of occasions with systolic blood pressure < 90 mm Hg, cough frequency, cumulative propofol dose, recovery time, maximum transcutaneous CO2 , mean SpO2 and O2 delivery during FB. RESULTS: Seventy-seven patients were included. TCI was noninferior to FPA in terms of mean (standard deviation) lowest SpO2 during the procedure (88.3% (5.4%) vs 86.9% (7.3%)) and required fewer dose adjustments (0.04/min vs 0.28/min, P < 0.001) but a higher cumulative propofol dose (264 vs 194 mg, P = 0.003). All other secondary outcomes were comparable between the groups. CONCLUSION: We suggest that TCI of propofol is a favourable sedation technique for FB with equal safety issues and fewer dose adjustments compared with FPA.

Avances en el manejo de la vía aérea: el futuro ya está aquí / Advances in airway management: the future is here

No disponible

Análisis de la regresión temporal en el ensanchamiento del intervalo QRS inducido por bupivacaína con la administración de Intralipid. Estudio en un modelo experimental porcino / Analysis of the temporal regression of the QRS widening induced by bupivacaine after Intralipid administration. Study in an experimental porcine model

Objetivo: La toxicidad cardiaca inducida por la bupivacaína (B) se relaciona con el bloqueo de los canales de sodio, que se traduce por un ensanchamiento del intervalo QRS. Estudios experimentales recientes, sugieren que el Intralipid (IL) es eficaz en revertir la toxicidad cardiaca de la B. Nuestro objetivo fue analizar la evolución temporal del ensanchamiento del QRS inducido por la B con la administración de IL. Material y método: Doce cerdos fueron anestesiados con tiopental sódico, 5 mg kg−1, y sevoflurano a concentración alveolar mínima de 2,6%. Tras la instrumentalización se administró un bolo de B de 4-6 mg kg−1 con el objetivo de inducir un aumento de 150% en la duración del QRS. El grupo IL recibió 1,5 mL kg−1 de IL seguido de 0,25 mL kg min−1; el grupo control (C) recibió salino. Se registraron los parámetros electrocardiográficos tras la infusión de B y a 1, 5,10 y 30 min de la administración de Intralipid/salino. Resultados: La administración de B (4,33°æ 0,81 mg/kg en el grupo IL y 4,66°æ 1,15 mg/kg en el grupo C) indujo cambios electrocardiográficos similares en ambos grupos; el porcentaje medio de incremento máximo en el QRS fue de 184°æ 62% en el grupo IL, y de 230°æ 56% en el grupo C. El IL revirtió el ensanchamiento del QRS inducido por la B, a los 10 min de su administración el intervalo QRS disminuyó 132°æ 56% vs. 15°æ 76%, en relación al máximo incremento inducido por la B, en el grupo IL y grupo C respectivamente. Conclusión: El IL revirtió eficazmente el ensanchamiento del intervalo QRS inducido por la B. El tiempo hasta la normalización de los parámetros electrocardiográficos puede prolongarse más de 10 min. Mientras persistan los fenómenos de toxicidad cardíaca, las medidas de resucitación y monitorización deben continuarse hasta que los parámetros de conducción cardíaca se hayan restaurado de forma adecuada (AU)

Objective: The principal mechanism of cardiac toxicity of bupivacaine relates to the blockade of myocardial sodium channels, which leads to an increase in the QRS duration. Recently, experimental studies suggest that lipid emulsion is effective in reversing bupivacaine cardiac toxicity. We aimed to evaluate the temporal evolution of the QRS widening induced by bupivacaine with the administration of Intralipid. Material and methods: Twelve pigs were anesthetized with intravenous sodium thiopental 5 mg kg−1 and sevoflurane 1 MAC (2.6%). Femoral artery and vein were canalized for invasive monitoring, analysis of blood gases and determination of bupivacaine levels. After instrumentation and monitoring, a bupivacaine bolus of 4-6 mg kg−1 was administered in order to induce a 150% increase in QRS duration (defined as the toxic point). The pigs were randomized into two groups of six individuals. Intralipid group (IL) received 1.5 mL kg−1of IL over one minute, followed by an infusion of 0.25 mL kg min−1. Control group (C) received the same volume of a saline solution. The electrocardiographic parameters were recorded, and blood samples were taken after bupivacaine and 1, 5, 10 and 30 minutes after Intralipid/saline administration. Results: Bupivacaine (4.33°æ 0.81 mg/kg in IL group and 4.66°æ 1.15 mg/kg in C group) induced similar electrocardiographic changes in both groups; mean maximal percent increase in QRS interval was 184°æ 62% in IL group, and 230°æ 56% in control group (NS). Lipid administration reversed the QRS widening previously impaired by bupivacaine. After ten minutes of the administration of IL, the mean QRS interval decreased to 132°æ 56% vs. 15°æ 76% relative to the maximum widening induced by bupivacaine, in IL and C group, respectively. Conclusion: Intralipid reversed the lengthening of QRS interval induced by the injection of bupivacaine. Time to normalization of electrocardiographic parameters can last more than 10 minutes. While the phenomena of cardiac toxicity persist, resuscitation measures and adequate monitoring should be continued until adequate heart conduction parameters are restored (AU)

Total intravenous anesthesia for aortic aneurysm replacement surgery in a patient with limb-girdle dystrophy / Anestesia total intravenosa para sustitución de aorta ascendente por aneurisma en paciente con distrofia muscular de cinturas

We report the anesthetic management with total intravenous anesthesia of a 61-year-old male diagnosed with limb-girdle muscular dystrophy admitted for replacement of ascending aorta due to an aortic aneurysm. Limb-girdle muscular dystrophy belongs to a genetically heterogeneous group of muscular dystrophies involving shoulder and hip girdles. Although the risk of malignant hyperthermia does not seem to be increased in these patients compared with the general population, the exposure to inhaled anesthetics and succinylcholine should probably be avoided because these patients have a predisposition to hyperkalemia and rhabdomyolysis. We chose to use total intravenous anesthesia with propofol, remifentanil and muscle relaxants to reduce oxygen consumption, and later to reduce the doses of propofol and remifentanil. The combination of a carefully planned anesthetic strategy, anesthetic depth, and neuromuscular blockade monitoring is explained (AU)

Presentamos el tratamiento anestésico con anestesia total intravenosa de un varón de 61 años diagnosticado de distrofia muscular de cinturas para sustitución de aorta ascendente por aneurisma aórtico. La distrofia muscular de cinturas es un grupo genéticamente heterogéneo de distrofias musculares que afecta predominantemente la cintura escapular y pélvica. Aunque el riesgo de hipertermia maligna no parece estar aumentado en estos pacientes en comparación con la población general, la exposición a anestésicos inhalatorios y succinilcolina probablemente deba evitarse ya que existe una predisposición a la hiperpotasemia y rabdomiólisis. Utilizamos anestesia intravenosa total con propofol y remifentanilo, además de bloqueanttes musculares durante el procedimiento quirúrgico, para reducir el consumo de oxígeno y minimizar las dosis de propofol y remifentanilo. La combinación de una estrategia anestésica cuidadosa, monitorización de bloqueo neuromuscular y profundidad anestésica se describen a continuación (AU)

The effect of ketamine with remifentanil for improving the quality of anaesthesia and recovery in paediatric patients undergoing middle-ear ventilation tube insertion.

This prospective randomized study evaluated the effects of ketamine with remifentanil to improve the quality of anaesthesia and postoperative recovery, following brief procedures, in 60 paediatric patients undergoing middle-ear ventilation tube insertion (MEVTI). Patients were randomly assigned to either ketamine 2 mg/kg intravenous [i.v.] bolus plus normal saline by i.v. infusion (K group, n = 30) or ketamine 2 mg/kg i.v. bolus, plus remifentanil 0.15 µg/kg per min i.v. infusion (KR group, n = 30). Parameters that were assessed included intraoperative patient movement, surgeon satisfaction, anaesthesia time, total ketamine dose, postoperative recovery time, agitation and side-effects. Intraoperative patient movement scores were significantly lower, and surgeon satisfaction scores were significantly higher, in the KR group than in the K group. Time to recovery was significantly shorter in the KR group than in the K group. In conclusion, remifentanil was a good adjuvant to ketamine, improving the quality of anaesthesia and postoperative recovery in children undergoing MEVTI.

Comparison of spectral entropy and bispectral index electroencephalography in coronary artery bypass graft surgery.

OBJECTIVE: The study's aim was to compare response entropy (RE) and state entropy (SE) with bispectral index (BIS) electroencephalography (EEG) as an alternative cerebral monitoring tool in patients scheduled for coronary artery bypass graft surgery. DESIGN: Prospective, observational single-center study. SETTING: University hospital. PARTICIPANTS: Thirty patients undergoing coronary artery bypass graft surgery receiving remifentanil-propofol anesthesia. INTERVENTIONS: Surgery was performed with cardiopulmonary bypass (CPB) and cardiac arrest in 15 patients, with CPB without cardiac arrest in 9 patients and without CPB in 6 patients. MEASUREMENTS AND MAIN RESULTS: RE, SE, BIS, burst suppression ratio (BSR), and frontal electromyography (f-EMG) were detected simultaneously. RE and SE compared favorably with BIS and their correlations were strong (r(2) = 0.6, r(2) = 0.55, respectively). The mean bias of RE and BIS was -1.8, but limits of agreement were high (+20.5/-24.1). RE and SE tended to be lower than the BIS values in the CPB subgroups. The detection of BSR was similar with RE and SE and the BIS. A strong correlation existed between BIS and f-EMG (r(2) = 0.62) in contrast to RE (r(2) = 0.45) and SE (r(2) =0.39). BIS monitoring was significantly more disturbed than RE and SE with 9.1% +/-10.9% and 0.1% +/- 0.2% of the total anesthesia time, respectively. Neither implicit nor explicit memory was shown. CONCLUSION: RE and SE are comparable with the BIS but showed significantly less interference from f-EMG and superior resistance against artifacts. Thus, spectral entropy is more suitable than the BIS during propofol-remifentanil anesthesia in cardiac surgery patients.

Clinical adaptation of a pharmacokinetic model of Propofol plasma concentrations in children.

BACKGROUND: A previously published pharmacokinetic simulation suggested a simple manual infusion regimen to achieve propofol plasma concentrations of 3 microg.ml(-1). This study investigated if a simple variation in propofol infusion rates is able to achieve distinct propofol plasma concentrations and whether these are close to the propofol plasma concentrations predicted by the Kataria model. METHODS: With Research Ethics Board approval and written parental consent, a total of 17 healthy children requiring general anaesthesia were enrolled. Following inhalational induction of anaesthesia, a propofol bolus of 5 mg.kg(-1) was given and anaesthesia maintained using an adaptation of the McFarlan continuous propofol infusion regimen to achieve three distinct depths of propofol anaesthesia. Weight and propofol infusion data were used to calculate simulated propofol concentrations using the Kataria dataset and the TIVA simulation program. The performance of the infusion regimen was assessed by calculating the median performance error, median absolute performance error, wobble, and divergence. RESULTS: Measured propofol concentrations were (mean +/- sd) 7.15 +/- 1.4, 4.3 +/- 0.85, and 2.85 +/- 0.53 microg.ml(-1) against simulation values of 6.6, 4.1, and 2.8 microg.ml(-1), respectively, at 30, 50, and 70 min using the Kataria dataset. These differences were not significant. Formal assessment of the infusion regimen's performance was acceptable. CONCLUSION: The manual propofol infusion regimen achieved three distinct depths of propofol anaesthesia. The manual infusion regimen produced higher plasma propofol concentrations than predicted during the early part of the infusion period but was more accurate for later time points.

Intravenous regional anesthesia administered by the operating plastic surgeon: is it safe and efficient? Experience of a medical center.

BACKGROUND: Intravenous regional anesthesia (Bier's block) is an effective method of providing anesthesia for extremity surgery. This technique is most suitable for short-duration, less than 60-minute surgical procedures in distal extremities. Earlier studies recommended that intravenous regional anesthesia be performed by anesthesiologists who are familiar with the technique and fully trained to treat its complications. This study was conducted to demonstrate that intravenous regional anesthesia administered by the operating plastic surgeon is safe, efficient, and simple to perform. METHODS: A 5-year retrospective chart review (January of 2000 to December of 2004) was undertaken. The study included patients who underwent surgical procedures and were administered intravenous regional anesthesia by the surgeon. RESULTS: Four hundred forty-eight patients were included in the study, and 479 operations of 483 scheduled were completed under intravenous regional anesthesia performed by the operating surgeon. Intravenous regional anesthesia was efficient in 478 of 479 of the cases (99.8 percent). Tourniquet-related technical problems were noted in five of 483 cases (1 percent), resulting in cancellation of four operations, with no reported consequent anesthetic toxicity. Minor complications were reported in six of 479 of the cases (1.2. percent). No major complications occurred. CONCLUSIONS: Despite earlier worries about the safety of intravenous regional anesthesia if not administered by anesthesiologists, the authors found that intravenous regional anesthesia represents a safe and efficient technique of anesthesia for extremity surgery when performed carefully and appropriately by the operating surgeon. The authors suggest that plastic surgeons familiarize themselves with this technique, which is simple to perform. This could probably result in lower overall costs and greater autonomy for the surgeon.