Jean Pierre P Ouanes

Analgesic efficacy of ultrasound-guided regional anesthesia: a meta-analysis

STUDY OBJECTIVE To determine if the use of ultrasound guidance (vs non-ultrasound techniques) improves the success rate of nerve blocks. DESIGN Meta-analysis of randomized controlled trials (RCTs) in the published literature. SETTING University medical center. MEASUREMENTS 16 RCTs of patients undergoing elective surgical procedures were studied. Patients underwent ultrasound-guided or non-ultrasound techniques (nerve stimulation, surface landmark) for peripheral nerve blocks. Success rates were measured. MAIN RESULTS Ultrasound guidance (vs all non-ultrasound techniques) was associated with a significant increase in the success rate of nerve blocks [relative risk (RR) = 1.11 (95% confidence interval [CI]: 1.06 to 1.17, P < 0.0001]). When compared with nerve stimulator techniques only, ultrasound guidance was still associated with an increase in the success rate (RR = 1.11 [95% CI: 1.05 to 1.17, P = 0.0001]). For specific blocks, ultrasound guidance (vs all non-ultrasound) was associated with a significant increase in successful brachial plexus (all) nerve blocks (RR = 1.11 [95% CI: 1.05 to 1.20, P = 0.0001]), sciatic popliteal nerve block (RR = 1.22 [95% CI: 1.08 to 1.39, P = 0.002]) and brachial plexus axillary nerve block (RR = 1.13 [95% CI: 1.00 to 1.26, P = 0.05]) but not brachial plexus infraclavicular nerve block (RR = 1.25 [95% CI: 0.88 to 1.76, P = 0.22]). CONCLUSIONS Ultrasound-guided peripheral nerve block is associated with an increased overall success rate when compared with nerve stimulation or other methods. Ultrasound-guided techniques also increase the success rate of some specific blocks.

The role of perioperative high inspired oxygen therapy in reducing surgical site infection: a meta-analysis.

BACKGROUND: The clinical role of hyperoxia for preventing surgical site infection remains uncertain because randomized controlled trials on this topic have reported disparate results. Our objective in this systematic review was to determine whether perioperative hyperoxia reduces surgical site infection. METHODS: An electronic search was conducted using the National Library of Medicines MEDLINE, Cochrane Collaborations CENTRAL, and EMBASE databases. Included studies consisted of randomized controlled trials in an adult population with a clearly defined comparison of high oxygen versus low oxygen or control, and with a documented assessment for perioperative infection. Pooled estimates for odds ratios (ORs) with 95% confidence intervals were obtained for our primary outcome (surgical site infection) using the Cochrane Collaborations RevMan version 5.0.25 (Cochrane Collaboration, Oxford, UK). ORs were calculated using a random effects model. RESULTS: The literature search ultimately yielded 7 trials, enrolling 2728 patients, that were included in the analysis. There were 1358 patients randomly assigned to hyperoxia and 1370 to control. The pooled infection rate in the hyperoxia group was 15.5% versus 17.5% in the control group. Hyperoxia resulted in an OR of 0.85 for surgical site infection (95% confidence interval: 0.52, 1.38) (P = 0.51). However, 2 subgroup analyses (general anesthesia and colorectal surgery trials) showed a benefit for high inspired oxygen therapy of decreasing surgical site infection. CONCLUSIONS: Perioperative high inspired oxygen therapy overall was not found to be beneficial for preventing surgical site infection based on this meta-analysis. The positive results of 2 subgroup analyses (general anesthesia and colorectal surgery trials) suggest a benefit for hyperoxia in decreasing surgical site infection. Additional studies are needed to further investigate this intervention.

No Pain Labor & Delivery: A Global Health Initiative's Impact on Clinical Outcomes in China.

The availability of labor analgesia is highly variable in the People’s Republic of China. There are widespread misconceptions, by both parturients and health care providers, that labor epidural analgesia is harmful to mother and baby. Meanwhile, China has one of the highest cesarean delivery rates in the world, exceeding 50%. The goal of the nongovernmental No Pain Labor & Delivery (NPLD) is to facilitate sustainable increases in vaginal delivery rates by increasing access to safe neuraxial labor analgesia, thereby decreasing the cesarean delivery rate. NPLD was launched in 2008 with the stated goal of improving labor outcome in China by increasing the absolute labor epidural analgesia rate by 10%. NPLD established 10 training centers over a 10-year period. We hypothesized that increased availability of labor analgesia would result in reduced requests for cesarean delivery and better labor outcomes for mother and baby. Multidisciplinary teams of Western clinicians and support staff traveled to China for 8 to 10 days once a year. The approach involved establishing 24/7 obstetric anesthesia coverage in Chinese hospitals through education and modeling multidisciplinary approaches, including problem-based learning discussions, bedside teaching, daily debriefings, simulation training drills, and weekend conferences. As of November 2015, NPLD has engaged with 31 hospitals. At 24 of these sites, 24/7 obstetric anesthesia coverage has been established and labor epidural analgesia rates have exceeded 50%. Lower rates of cesarean delivery, episiotomy, postpartum blood transfusion, and better neonatal outcomes were documented in 3 impact studies comprising approximately 55,000 deliveries. Changes in practice guidelines, medical policy, and billing codes have been implemented in conjunction with the modernization of perinatal practice that has occurred concurrently in China since the first NPLD trip in 2008.

Special Anesthetic Consideration for the Patient with a Fragility Fracture

In this article, an overview is presented of perioperative management of the patient with a fragility fracture, including preoperative risk stratification and optimization, anesthesia risks, anesthesia options, and postoperative pain management. Issues of preoperative evaluation that are of concern for the anesthesiologist because of their direct effect on intraoperative care are discussed. A team interdisciplinary approach and good communication between specialties involved in care of elderly surgical patients is important for optimal patient outcomes and to avoid perioperative complications. Cooperation between anesthesiology and medicine is indispensable in reaching a reasonable consensus regarding preoperative evaluation and should occur on a case-by-case basis.

Evaluation of epidural and peripheral nerve catheter heating during magnetic resonance imaging

Background Many epidural and peripheral nerve catheters contain conducting wire that could heat during magnetic resonance imaging (MRI), requiring removal for scanning. Methods We tested 2 each of 6 brands of regional analgesia catheters (from Arrow International [Reading, Pennsylvania], B. Braun Medical Inc [Bethlehem, Pennsylvania], and Smiths Medical/Portex [Keene, New Hampshire]) for exposure to clinical 1.5- and 3-T MRI. Catheters testing as nonmagnetic were placed in an epidural configuration in a standard human torso–sized phantom, and an MRI pulse sequence applied at the maximum scanner-allowed radiofrequency specific absorption rate (SAR) for 15 minutes. Temperature and SAR exposure were sampled during MRI using multiple fiberoptic temperature sensors. Results Two catheters (the Arrow StimuCath Peripheral Nerve and B. Braun Medical Perifix FX Epidural) were found to be magnetic and not tested further. At 3 T, exposure of the remaining 3 epidural and 1 peripheral nerve catheter to the scanner’s maximum RF exposure elicited anomalous heating of 4°C to 7°C in 2 Arrow Epidural (MultiPort and Flex-Tip Plus) catheters at the entry points. Temperature increases for the other catheters at 3 T, and all catheters at 1.5 T were 1.4°C or less. When normalized to the body-average US Food and Drug Administration guideline SAR of 4 W/kg, maximum projected temperature increases were 0.1°C to 2.5°C at 1.5 T and 0.7°C to 2.7°C at 3 T, except for the Arrow MultiPort Flex-Tip Plus catheter at 3 T whose increase was 14°C. Conclusions Most but not all catheters can be left in place during 1.5-T MRI scans. Heating of less than 3°C during MRI for most catheters is not expected to be injurious. While heating was lower at 1.5 T versus 3 T, performance differences between products underscore the need for safety testing before performing MRI.

The role of perioperative chewing gum on gastric fluid volume and gastric pH: a meta-analysis.

STUDY OBJECTIVE To determine if preoperative gum chewing affects gastric pH and gastric fluid volume. DESIGN Systematic review and meta-analysis. METHODS Data sources included Cochrane, PubMed, and EMBASE databases from inception to June 2012 and reference lists of known relevant articles without language restriction. Randomized controlled trials in which a treatment group that chewed gum was compared to a control group that fasted were included. Relevant data, including main outcomes of gastric fluid volume and gastric pH, were extracted. RESULTS Four studies involving 287 patients were included. The presence of chewing gum was associated with small but statically significant increases in gastric fluid volume (mean difference = 0.21 mL/kg; 95% confidence interval, 0.02-0.39; P = .03) but not in gastric pH (mean difference = 0.11 mL/kg; 95% confidence interval, -0.14 to 0.36; P = .38). Gastric fluid volume and gastric pH remained unchanged in subgroup analysis by either sugar or sugarless gum type. CONCLUSIONS Chewing gum in the perioperative period causes small but statically significant increases in gastric fluid volume and no change in gastric pH. The increase in gastric fluid most likely is of no clinical significance in terms of aspiration risk for the patient. Elective surgery should not necessarily be canceled or delayed in healthy patients who accidentally chew gum preoperatively.

Effect of Depth of Sedation in Older Patients Undergoing Hip Fracture Repair on Postoperative Delirium: The STRIDE Randomized Clinical Trial

Importance Postoperative delirium is the most common complication following major surgery in older patients. Intraoperative sedation levels are a possible modifiable risk factor for postoperative delirium. Objective To determine whether limiting sedation levels during spinal anesthesia reduces incident delirium overall. Design, Setting, and Participants This double-blind randomized clinical trial (A Strategy to Reduce the Incidence of Postoperative Delirum in Elderly Patients [STRIDE]) was conducted from November 18, 2011, to May 19, 2016, at a single academic medical center and included a consecutive sample of older patients (≥65 years) who were undergoing nonelective hip fracture repair with spinal anesthesia and propofol sedation. Patients were excluded for preoperative delirium or severe dementia. Of 538 hip fractures screened, 225 patients (41.8%) were eligible, 10 (1.9%) declined participation, 15 (2.8%) became ineligible between the time of consent and surgery, and 200 (37.2%) were randomized. The follow-up included postoperative days 1 to 5 or until hospital discharge. Interventions Heavier (modified observer’s assessment of sedation score of 0-2) or lighter (observer’s assessment of sedation score of 3-5) propofol sedation levels intraoperatively. Main Outcomes and Measures Delirium on postoperative days 1 to 5 or until hospital discharge determined via consensus panel using Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) criteria. The incidence of delirium was compared between intervention groups with and without stratification by the Charlson comorbidity index (CCI). Results Of 200 participants, the mean (SD) age was 82 (8) years, 146 (73%) were women, 194 (97%) were white, and the mean (SD) CCI was 1.5 (1.8). One hundred participants each were randomized to receive lighter sedation levels or heavier sedation levels. A good separation of intraoperative sedation levels was confirmed by multiple indices. The overall incident delirium risk was 36.5% (n = 73) and 39% (n = 39) vs 34% (n = 34) in heavier and lighter sedation groups, respectively (P = .46). Intention-to-treat analyses indicated no statistically significant difference between groups in the risk of incident delirium (log-rank test &khgr;2, 0.46; P = .46). However, in a prespecified subgroup analysis, when stratified by CCI, sedation levels did effect the delirium risk (P for interaction = .04); in low comorbid states (CCI = 0), heavier vs lighter sedation levels doubled the risk of delirium (hazard ratio, 2.3; 95% CI, 1.1- 4.9). The level of sedation did not affect delirium risk with a CCI of more than 0. Conclusions and Relevance In the primary analysis, limiting the level of sedation provided no significant benefit in reducing incident delirium. However, in a prespecified subgroup analysis, lighter sedation levels benefitted reducing postoperative delirium for persons with a CCI of 0. Trial Registration clinicaltrials.gov Identifier: NCT00590707

Comparison of Air and Liquid for Use in Loss-of-Resistance Technique During Labor Epidurals: A Meta-analysis

Background: Air and saline are commonly used in the loss-of-resistance technique to identify the epidural space. However, it is unclear which method promotes more effective analgesic delivery after subsequent epidural catheter placement. Methods: We conducted a meta-analysis to determine the efficacy of air and saline identification methods. We performed a systematic literature search of the National Library of Medicine’s PubMed database using terms related to air, saline, epidural, and loss of resistance. Only randomized controlled trials that compared air with saline or local anesthetic were included for analysis. No restrictions were placed on the language of identified articles. Data on pertinent study characteristics and relevant outcomes were extracted from accepted articles. A random effects model was used. Results: The literature search yielded six articles that met all inclusion criteria. A review of the articles reveal 515 subjects for whom air had been used to identify the epidural space and 522 for whom liquid had been used. We were able to obtain pooled estimates for unblocked segments, need for additional medications, and replaced catheters. Use of air was associated with an increased risk for unblocked segments [relative risk (RR) = 2.12, 95% confidence interval (CI): 1.07, 4.21; p = 0.03], but there was no difference with regard to replaced catheters [RR = 0.69, 95% CI: 0.26, 1.82; p = 0.45] or additional medication [RR = 1.59, 95% CI: 0.85, 2.41; p = 0.18]. Conclusion: Our pooled analysis revealed that use of air in the loss-of-resistance technique results in decreased analgesia in one parameter (unblocked segments) but not others (additional medications, replaced catheters). The results should be interpreted with caution, and additional examination with a larger randomized controlled trial is warranted, as the overall number of subjects was relatively small.