Sylvia H. Wilson

Regional Anesthesia for Breast Surgery: Techniques and Benefits

Breast surgery is an exceedingly common procedure and associated with an increased incidence of acute and chronic pain. Regional anesthesia techniques may improve postoperative analgesia for patients undergoing breast surgery. While much data have supported the efficacy of paravertebral blocks, they are not without risks. More recently, pectoral blocks have shown promise for this population, whereas wound infiltration has demonstrated mixed results. In this review, regional anesthesia techniques, the associated anatomy and the evidence for their utility are reviewed. Additionally, the advantages of regional anesthesia beyond postoperative pain control are discussed.

A Prospective Observational Study of Ethnic and Racial Differences in Neuraxial Labor Analgesia Request and Pain Relief

BACKGROUND:As ethnic and racial diversity increases, it is important that anesthesia providers understand the expectations and concerns of this changing population regarding labor analgesia. Our objective was to evaluate ethnic/racial differences in labor analgesia characteristics with regard to the timing of request for neuraxial analgesia. METHODS:Three hundred ninety-seven parturients were enrolled in this prospective observational cohort study. Term laboring parturients who planned vaginal delivery and requested neuraxial labor analgesia were eligible for inclusion. Data collected included cervical dilation at the time of neuraxial analgesia request, self-identified ethnicity/race, parity, education, insurance status, pain score before and after the initiation of neuraxial analgesia, and mode of delivery. The primary outcome was cervical dilation at the time of neuraxial analgesia request. Ethnicity/race classification was determined by asking the patient, “How would you define your ethnicity?” Patients were categorized into the ethnic/racial groups of non-Hispanic White, African American, Hispanic, or other. Univariate associations between cervical dilation and categorical variables were examined. Multivariate analysis was performed for the primary outcome of cervical dilation at the time of initiation of neuraxial analgesia. RESULTS:At the time of neuraxial analgesia placement, the mean difference in cervical dilation of Hispanic parturients was 0.8 cm compared to non-Hispanic Whites (95% confidence interval [CI], 0.1–1.4; P = 0.047). After controlling for education, reason for placement, labor augmentation, and mode of delivery in a multivariate model, Hispanic parturients had 0.5 cm greater cervical dilation compared to non-Hispanic Whites, which was not significant (95% confidence interval, −0.1 to 1.1; P = 0.089). CONCLUSIONS:Our data indicate that ethnicity/race plays a small role in acceptance and request for neuraxial labor analgesia.

Perineural Versus Systemic Dexamethasone: Questions Remain Unanswered.

or that the adductor canal is a continuation of the femoral triangle. The important point that we, Tubbs et al, and Dr Bendtsen et al make is that “The vastoadductormembrane effectively creates a subcompartmentwithin the subsartorial canal.” The vastoadductor membrane separates the subsartorial plexus from the saphenous nerve contained in the “adductor canal proper” as stated in Dr Bendtsen’s aforementioned correspondence. Hence, there is a subsartorial space (or canal, if we may) containing a neural plexus that needs to be considered when providing lower limb analgesia/anesthesia. The other point we made is that the commencement and length of the adductor canal are highly variable. Tubbs’ dissection study reported a range of 20 to 32 cm for the former (from the anterior superior iliac spine to the proximal border of the vastoadductor membrane) and 5.5 to 15 cm for the latter. Thus, it is highly probable that many clinicians are injecting superior to the adductor canal when performing an adductor canal block. As our letter states, we insert our catheter in to the femoral triangle using an easily definable sonoanatomical end point. Injection of dye at this point results in minimal spread superiorly and consistent spread inferiorly, posterior to the sartorius. These results are consistent with the anatomical dye study of Ishiguro et al. We routinely insert femoral nerve catheters at this position for patients undergoing knee replacement surgery. In our experience, a continuous catheter infusion of 5 to 10 mL of 0.2% ropivacaine produces reliable analgesia of the knee, with preservation of quadriceps strength. Patients routinely walk within 24 hours of surgery. To reiterate, we believe that it is important to achieve subsartorial spread of local anesthetic anterior and posterior of the vastoadductor membrane to provide excellent analgesia for knee arthroplasty surgery. We suggested the term “subsartorial canal block” to encompass the subsartorial space and not just the “adductor canal proper.” However, we accept that there remains some ambiguity of terminology.

A Retrospective Study Evaluating the Effect of Low Doses of Perineural Dexamethasone on Ropivacaine Brachial Plexus Peripheral Nerve Block Analgesic Duration

Objective Examination of the effectiveness of perineural dexamethasone administered in very low and low doses on ropivacaine brachial plexus block duration. Design Retrospective evaluation of brachial plexus block duration in a large cohort of patients receiving peripheral nerve blocks with and without perineural dexamethasone in a prospectively collected quality assurance database. Setting A single academic medical center. Methods A total of 1,942 brachial plexus blocks placed over a 16-month period were reviewed. Demographics, nerve block location, and perineural dexamethasone utilization and dose were examined in relation to block duration. Perineural dexamethasone was examined as none (0 mg), very low dose (2 mg or less), and low dose (greater than 2 mg to 4 mg). Continuous catheter techniques, local anesthetics other than ropivacaine, and block locations with fewer than 15 subjects were excluded. Associations between block duration and predictors of interest were examined using multivariable regression models. A subgroup analysis of the impact of receiving dexamethasone on block duration within each block type was also conducted using a univariate linear regression approach. Results A total of 1,027 subjects were evaluated. More than 90% of brachial plexus blocks contained perineural dexamethasone (≤4 mg), with a median dose of 2 mg. Increased block duration was associated with receiving any dose of perineural dexamethasone (P < 0.0001), female gender (P = 0.022), increased age (P = 0.048), and increased local anesthetic dose (P = 0.01). In a multivariable model, block duration did not differ with very low- or low-dose perineural dexamethasone after controlling for other factors (P = 0.420). Conclusion Perineural dexamethasone prolonged block duration compared with ropivacaine alone; however, duration was not greater with low-dose compared with very low-dose perineural dexamethasone.

Updated Difficult Airway Algorithm: Confusing and Contradictory

To the Editor: We read with great interest and some concern the revised Practice Guidelines for Management of the Difficult Airway.1 The Difficult Airway Algorithm, presented in figure 1, has some confusing recommendations. could be devastating if not immediately successful. In these cases, the choice of an awake technique is clear and indeed the safest route with a long track record.3 The current algorithm, as written, would not assist a practitioner in this sort of situation simply because ventilation would not necessarily be predicted to be difficult. When such guidelines are generated, our society must recognize that other societies look to the American Society of Anesthesiologists for guidance and expertise. For example Emergency Medicine physicians and Critical Care physicians use our Difficult Airway Algorithm to guide and support their decision making and patient care. Omitting a critical component such as the aspiration risk assessment from this latest version may subject patients to undue risk, especially as skills with awake techniques like flexible bronchoscopy seem to be continually deemphasized in the literature for various reasons.4,5 Perhaps the task force might recognize the potential gravity of the omission of assessment of a patient’s risk to aspirate and amend the current guidelines so that 10 more years do not need to lapse before it is included.

Effect of Subcutaneous Unfractionated Heparin Prophylaxis on Activated Partial Thromboplastin Time: A Retrospective Evaluation ☆ ☆☆ ★ ★★ ☆☆☆

STUDY OBJECTIVE Characterize the incidence of elevated aPTT results in patients treated with prophylactic, subcutaneous unfractionated heparin (UFH). DESIGN Retrospective, cohort analysis. SETTING Single-center, university hospital. MEASUREMENTS Evaluation of 257 patients with activated partial thromboplastin time (aPTT) testing both prior to and following subcutaneous (SC) unfractionated heparin (UFH) therapy. MAIN RESULTS Evaluated patients received UFH 5000 units every 8 hours. Baseline aPTT values were within the normal range (mean±SD, 32.0±8.5 seconds). After initiation of UFH, aPTT values increased (mean±SD, 37.6±15.2 seconds). After 24 hours of SC UFH, mean aPTT values (mean±SD, 38.6±15.5) exceeded the normal laboratory range (23.3-35.7 seconds). An elevated aPTT result after UFH was associated with baseline aPTT, length of therapy, and weight-based UFH dose. A significant association was not identified between aPTT elevation and age, race, sex, history of liver disease, type of admission, or transfusion of blood products. CONCLUSIONS Treatment with UFH resulted in a small, but significant, increase in aPTT.

Epidural removal after perioperative myocardial infarction and coronary stent placement.

We report the case of a 77-year-old, 72.3-kg, white man with degenerative joint disease, anemia, thalassemia minor, and tobacco abuse but otherwise negative history and preoperative evaluation, who experienced an ST-segment elevation myocardial infarction (STEMI) after total hip arthroplasty with an indwelling epidural catheter. Written consent and an institutional review board exemption were obtained to report this case. On skin closure, ST-segment elevations developed and ventricular fibrillation soon followed. Advanced cardiovascular life support protocols restored sinus rhythm, and systemic anticoagulation was initiated (intravenous unfractionated heparin, rectal clopidogrel, and aspirin). On cardiac catheterization, multivessel disease was diagnosed and a bare metal stent was placed. The patient was transferred to the intensive care unit, intubated, and sedated. Based on platelet aggregometry that revealed 0% inhibition of platelets and normal coagulation studies, the epidural catheter was removed. The patient was extubated on postoperative day 1 and later discharged to a skilled nursing facility free of neurologic deficits. Neuraxial catheter removal in conjunction with thienopyridines carries the risk of spinal hematoma formation; however, dual antiplatelet therapy is a central component in the management of STEMI patients. Thienopyridine effects are time and dose dependent, with loading doses accelerating attainment of steady state. Platelet function testing may help determine the risk of thrombotic or hemorrhagic events while using antiplatelet therapy. The VerifyNow System (Accumetrics, Inc, San Diego, California) was used to investigate the effects of clopidogrel on our patient. Although the VerifyNow system lacks the sensitivity of “gold standard” conventional platelet aggregometry, it has been shown to provide significant correlation to platelet aggregometry in patients undergoing dual antiplatelet therapy. Given the emergent nature of the clinical dilemma presented, rapid point-ofcare information (VerifyNow) assisted in the clinical decision for neuraxial catheter removal. Three previous case reports have described similar situations, except medications were held until laboratory data normalized, resulting in 1 indwelling epidural catheter for 4 weeks. This case differs because it demonstrates that early assessment may permit epidural catheter removal without cessation of antiplatelet therapy.

The Influence of a Single Preoperative Ketorolac Dose on Postoperative Opiate Consumption for Ambulatory Knee Arthroscopy: A Double Blinded Placebo Controlled Study

Objectives: Ketorolac is a non-steroidal anti-inflammatory known to decrease postoperative opiate requirements. While many studies have examined serial ketorolac doses over 48 hours, the optimal ketorolac dose for analgesia following ambulatory surgery is not established. We examined postoperative opiate consumption in morphine equivalents (ME) for patients receiving a randomized ketorolac dose for knee arthroscopy. Methods: Patients undergoing elective, outpatient knee arthroscopy were randomized a dose of ketorolac (0 mg, 7.5 mg, 15 mg, 30 mg) in a double blinded placebo controlled fashion. Postoperative opiate consumption was the primary outcome. Secondary endpoints were patient satisfaction score, Visual Analog Pain Scores (VAS) pre- and postoperative, side effects and total PACU time. Logistic regression was used to compare the results among the different ketorolac groups. Results: A total of 112 patients were enrolled with comparable patient and procedural characteristics in each group. Mean postoperative opiate consumption in ME was 6.36 mg across all groups. The median VAS at PACU arrival was 3.0 and at discharge was 1.6. Median patient satisfaction across all treatment groups was 9.8 out of 10. In univariate models, increased postoperative morphine consumption was associated with decreased ketorolac dose (P=0.037) and female gender (P=0.021). In a multivariable model, patients that received 7.5 fewer mg of ketorolac consumed on average 0.6 mg more ME postoperatively controlling for other factors (P=0.034). Females consumed an average of 2.3 mg more opiates relative to males after controlling for ketorolac dose (P=0.006). Ketorolac dose was not associated with the occurrence of side effects (P=0.722). Side effects were associated with female gender (P=0.023) and increased BMI (P=0.022). Consumption of each additional 1 mg of postoperative ME had a 13% increase in the odds of having at least one side effect controlling for other factors (P=0.026, 95% CI: 1.02-1.26). Conclusion: Decreased ketorolac dose is associated with increased opiate consumption controlling other factors. Increased opiate consumption may result in increased side effects, although this did not impact patient satisfaction.

Neuraxial hypothermia incidence misinterpreted

We readwith interest the recent systematic review by Shaw et al. [1] and applaud the authors for discussing the prevalence of perioperative hypothermia in patients receiving neuraxial anesthetics. However, we have concerns that they have inaccurately interpreted the data of a 2017 publication by Frisch et al. [2] examining hypothermia in patients undergoing total hip and knee arthroplasty, a population that often receives neuraxial anesthesia. When describing the Frisk et al. study, the Shaw et al. publication states that “those receiving neuraxial anesthesia were more likely to be hypothermic than those receiving general anesthesia (52% vs. 48%, p b 0.001).” This is, in fact, not accurate. Table 2 within the Frisch et al. study does list that 52% of hypothermic patients had regional anesthesia; however, the vastmajority of patients received regional anesthesia over general anesthesia (64% vs. 36%, respectively). Thus, 457 patients out of 1541 patients in the regional anesthetic group developed hypothermia (30%), compared to 430 patients out of 856 patients in the general anesthetic group (50%). In calculating an odds ratio, we estimate that patients who received general anesthesia had 2.4 times the odds of developing hypothermia relative to patients who received regional anesthesia (p b 0.001, 95% CI: 2.01–2.84). We emphatically agree that hypothermia does occur in patients receiving neuraxial anesthesia, and it is a potentially modifiable variable to study in this

Graft reperfusion of transplanted liver–perfect storm for coronary vasospasm

Major adverse cardiac events in patients during liver transplantation are due to preexisting cardiopulmonary comorbidities and the impact of surgery on hemodynamics. Graft reperfusion of the transplanted liver is the most hemodynamically critical phase and can be associated with air embolism and the release of acidotic, cold, hyperkalemic effluent containing vaso-constrictive chemical mediators such endothelin-1 and thromboxane A2. Concomitant release of oxygen reactive species can further sensitize the coronary vasculature to vasoconstrictors creating the perfect milieu for coronary vasospasm. We report a case in which myocardial ischemia accompanied by significant ST depression followed reperfusion possibly caused by coronary vasospasm. Correspondence to: Latha Hebbar, Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, South Carolina, USA, E-mail: hebbarl@musc.edu Received: November 08, 2016; Accepted: December 24, 2016; Published: December 28, 2016 Introduction End-stage liver disease affects every organ system in the body leading to a very exhaustive preoperative workup to determine eligibility for a potential liver transplant. The AHA/ACA have established guidelines for cardiac workup of these patients, however, the frequency of surveillance while on the transplant waiting list is yet to be determined [1]. The anesthetic management of these cases is challenging with reperfusion of the transplanted graft being the most critical period. Hemodynamic changes observed during graft reperfusion include decreases in systemic vascular resistance (SVR) and mean arterial blood pressure (MAP), dysrhythmias, abrupt increases in mean PA pressure, CVP and PCWP, myocardial ischemia and cardiac arrest [2,3]. The causes of this spectrum of hemodynamic instability are multifactorial and complex. They include the sudden release of cold, acidotic, hyperkalemic preservation fluid along with vasoactive mediators into the systemic circulation, surgical anastomotic mishaps with accompanying blood loss and air embolism causing right ventricular outflow tract obstruction and failure [2-5]. Myocardial ischemia with accompanying ST-T wave changes can occur during graft reperfusion. An imbalance of myocardial oxygen supply vs demand due to systemic hypotension, profound anemia or paradoxical coronary air embolism could be contributory. We report a case of myocardial ischemia during liver reperfusion attributed to coronary vasospasm. The setting of graft reperfusion with associated decreases in core temperature, increases in endothelin-1 and thromboxane A2 levels and increases in reactive oxygen species (ROS) creates a perfect storm for this clinical phenomenon. This report describes the care of one patient who has provided us with written consent to disclose the management of his case.