Roman Kluger

Ultrasound guidance reduces the risk of local anesthetic systemic toxicity following peripheral nerve blockade.

Background and Objectives Local anesthetic systemic toxicity (LAST) is a potentially life-threatening complication of local anesthetic administration. In this article, the results of the Australian and New Zealand Registry of Regional Anaesthesia were analyzed to determine if ultrasound-guided peripheral nerve blockade (PNB) was associated with a reduced risk of LAST compared with techniques not utilizing ultrasound technology. Methods The period of study for this multicenter study involving 20 hospitals was from January 2007 through May 2012. The primary outcome was LAST comprising minor, major, and cardiac arrest (due to toxicity) events determined using standardized definitions. Multivariable logistic regression models and propensity score analyses were used to determine significant event predictors. Results The study population comprised 20,021 patients who received 25,336 PNBs. There were 22 episodes of LAST, resulting in an incidence of LAST of 0.87 per 1000 PNBs (95% confidence interval, 0.54–1.3 per 1000). Ultrasound guidance was associated with a reduced incidence of local anesthetic toxicity. Site of injection, local anesthetic type, dose per weight, dose, and patient weight were all predictors of LAST. Conclusions This study provides the strongest evidence, to date, that ultrasound guidance may improve safety because it is associated with a reduced risk of LAST following PNB.

Epidural anesthesia for coronary artery bypass surgery compared with general anesthesia alone does not reduce biochemical markers of myocardial damage.

High thoracic epidural anesthesia/analgesia (HTEA) for coronary artery bypass grafting (CABG) surgery may have myocardial protective effects. In this prospective randomized controlled study, we investigated the effect of HTEA for elective CABG surgery on the release of troponin I, time to tracheal extubation, and analgesia. One-hundred-twenty patients were randomized to a general anesthesia (GA) group or a GA plus HTEA group. The GA group received fentanyl (7–15 &mgr;g/kg) and a morphine infusion. The HTEA group received fentanyl (5–7 &mgr;g/kg) and an epidural infusion of ropivacaine 0.2% and fentanyl 2 &mgr;g/mL until postoperative Day 3. There were no differences in troponin I levels between study groups. The time to tracheal extubation [median (interquartile range)] in the HTEA group was 15 min (10–320 min), compared with 430 min (284–590 min) in the GA group (P < 0.0001). Analgesia was improved in the HTEA group compared with the GA group. Mean arterial blood pressure poststernotomy and systemic vascular resistance in the intensive care unit were lower in the HTEA group. We conclude that HTEA for CABG surgery had no effect on troponin release but improved postoperative analgesia and was associated with a reduced time to extubation.

Stimulating Catheters for Continuous Femoral Nerve Blockade After Total Knee Arthroplasty : A Randomized, Controlled, Double-Blinded Trial

BACKGROUND: Continuous femoral nerve blockade (CFNB) is often used for postoperative analgesia after total knee arthroplasty (TKA). CFNB can be instituted using a variety of techniques. Stimulating catheters (SC) have the advantage of confirming placement of the catheter close to the nerve during advancement. METHODS: In this randomized, controlled, double-blind trial, we compared a SC with a nonstimulating catheter (NSC) technique for institution of CFNB and its effects on quality of analgesia after TKA performed under general anesthesia in 82 patients. Patients were randomized to have CFNB instituted using either a NSC or a SC technique. Sensory blockade was assessed 10 and 20 min after injection of lidocaine via femoral catheter and on postoperative days 1 (POD 1) and 2 (POD 2). A standardized multimodal analgesic technique, including a single injection sciatic block (preoperative), IV morphine (patient-controlled analgesia), celecoxib, and paracetamol, was administered to all patients. Outcome variables included morphine requirements, pain scores, and markers of early recovery. RESULTS: The proportion of patients with sensory blockade in the femoral nerve distribution was between 90% and 95% at all measurement times with no difference between groups. In the first 24 h, the NSC group required 19.5 (1–67) [median (10th–90th centiles)] mg morphine compared with the SC Group 18 (2–51) mg (P = 0.69). At 24 h, the 95% confidence interval for difference in morphine consumption between groups was −8 to 5 mg. There was no difference between groups in visual analog scale scores at rest on POD 1 and POD 2, during active and passive physiotherapy; and in markers of early recovery after surgery. CONCLUSIONS: In this study, blind catheter advancement was as reliable as a SC technique for establishing and maintaining CFNB for postoperative analgesia as a part of multimodal analgesia technique after TKA.

Evaluation of systolic murmurs using transthoracic echocardiography by anaesthetic trainees.

Focused transthoracic echocardiography by anaesthetists in the peri‐operative period has recently been described; the data suggest that the specific skills required can be obtained by non cardiology physicians with limited training. Aortic stenosis is known to increase significantly the peri‐operative risk in non‐cardiac surgery. This study aimed to assess the ability of echocardiography naive trainee anaesthetists to recognise and assess the severity of aortic stenosis after a set amount of training. Five trainees underwent 2 h of didactic and hands‐on teaching in evaluation of the aortic valve, after which they scanned 20 patients each. Their results were compared with those obtained by an experienced cardiac anaesthetist with echocardiography training and qualifications. There was 100% concordance between trainees and the consultant for assessment of clinically significant aortic stenosis, with no cases of misdiagnosis. There was also 90–100% agreement (kappa statistic 0.8–1) between the consultant and each trainee’s assessment of clinically significant aortic stenosis based on a peak aortic velocity > 3 m.sec−1. Anaesthesia trainees can be successfully and rapidly trained to recognise and estimate the severity of aortic stenosis.

Carbon dioxide field flooding versus mechanical de-airing during open-heart surgery: a prospective randomized controlled trial

Removal of intracardiac air during valvular surgery should be accomplished in the most effective manner. We conducted a prospective randomized controlled trial to compare mechanical de-airing and carbon dioxide (CO2) field flooding in 18 patients undergoing elective valvular surgery. Transoesophageal echocardiography was used to record intracardiac bubbles, and this was assessed postoperatively by two independent echocardio-graphers blinded to treatment group. Both assessors graded the bubble count higher in the mechanical de-airing group compared with the CO2 flooding group, and there was good agreement between assessors. CO2 field flooding is more effective than mechanical de-airing in removing intracardiac bubbles following valvular surgery.

Flow reversal in the descending aorta: a guide to intraoperative assessment of aortic regurgitation with transesophageal echocardiography.

This study assessed the value of biplane transesophageal echocardiographic assessment of diastolic flow reversal in the descending aorta as an alternative to Doppler color flow imaging in determining severity of aortic regurgitation. In 45 patients undergoing cardiac operations, the severity of aortic regurgitation was assessed by semiquantitative grading of the width of the Doppler color flow regurgitant jet relative to the left ventricular outflow tract, and the presence of diastolic flow reversal was assessed with pulsed-wave Doppler measurements at three sites in the descending aorta. In four patients, the diastolic flow reversal method was the only available form of assessment because of inadequate visualization of the left ventricular outflow tract beneath a mitral valve prosthesis. Diastolic flow reversal in the descending aorta was not observed in patients without aortic regurgitation and was always present in patients with severe aortic regurgitation. Aortic valve replacement successfully eliminated descending aortic flow reversal in all 19 patients in whom it was present before valve replacement. Identification of diastolic flow reversal at multiple sites in the descending aorta with biplane transesophageal echocardiography helps to confirm the presence of severe aortic regurgitation and can serve as an alternative method of assessment when visualization of the left ventricular outflow tract is impaired.

ε-aminocaproic Acid in Coronary Artery Bypass Graft SurgeryPreincision or Postheparin?

BACKGROUND Epsilon-aminocaproic acid (epsilon-ACA), an antifibrinolytic agent, is used in cardiac surgery to decrease postoperative bleeding. Theoretical concerns exist about the potential for epsilon-ACA to contribute to thrombotic complications. For this reason epsilon-ACA administration is sometimes delayed until after heparinization. This study investigated the impact of the timing of epsilon-ACA administration on its efficacy. METHODS In this double-blind study, 90 patients undergoing primary coronary artery bypass graft surgery were prospectively randomized to receive either epsilon-ACA commencing prior to skin incision (bolus 150 mg/kg, followed by an infusion at 15 mg x kg(-1) x hr(-1), epsilon-ACA commencing after heparin (same doses), or placebo. All infusions were terminated at the end of cardiopulmonary bypass. Criteria for the transfusion of blood products were standardized. Postoperative chest tube drainage (at 6 h, 12 h, and at chest tube removal) and blood transfusion requirements of the three groups were compared. RESULTS At all time intervals, the placebo group had significantly greater chest tube drainage than either of the two epsilon-ACA groups (P < 0.005). At no time did a significant difference exist between the two epsilon-ACA groups. A trend existed for the placebo group to require more blood products than either epsilon-ACA group. CONCLUSIONS Epsilon-ACA produces a reduction in chest tube drainage in patients undergoing primary coronary artery bypass graft surgery. This effect is similar whether the drug is given prior to incision or following anticoagulation. Given the similar hemostatic efficacy and the theoretical potential for thrombotic complications, it may be prudent to administer epsilon-ACA following anticoagulation.

Defining intra-operative hypotension – a pilot comparison of blood pressure during sleep and general anaesthesia*

The scientific justification for particular values of intra‐operative hypotension is poorly substantiated. To provide a rationale for appropriate values we recorded blood pressure measurements at home for 24 h using an automated non‐invasive ambulatory blood pressure measurement device. These blood pressures were compared with blood pressure measured before and during general anaesthesia in 18 subjects undergoing elective day surgery. We confirmed that a pre‐operative reading taken upon admission to hospital is significantly elevated compared to a usual daytime blood pressure in the same patient. The median (IQR [range]) increases in systolic and mean arterial pressures were 10 (2–15 [−5 to 59]) mmHg, p = 0.003 and 10 (5–14 [−5 to 35]) mmHg, p = 0.002, respectively. When using this admission blood pressure measurement as a ‘baseline’, systolic and mean arterial pressures decreased during sleep by 41 (30–46 [6–83]) mmHg and 34 (26–36 [6–58]) mmHg, respectively (p = 0.001). This decreased even further intra‐operatively: systolic blood pressure by 49 (36–64 [15–96]) mmHg and mean arterial pressure by 36 (26–46 [8–66]) mmHg (p = 0.001).

Are patients satisfied after peripheral nerve blockade? Results from an International Registry of Regional Anesthesia.

Introduction Peripheral nerve blockade (PNB) is associated with superior outcomes compared with opioids; however, little is known regarding patients’ perceptions of the care they have received. Patient satisfaction is emerging as an important indicator of quality of health care, and identifying deficiencies in discrete aspects of satisfaction may allow targeted interventions to improve quality. In this study, we analyze data relevant to patient satisfaction from the International Registry of Regional Anesthesia. The primary objective of this analysis was to report the results of a patient-satisfaction questionnaire and to determine predictors associated with unwillingness to have PNB repeated in the case of future surgery. Methods The questionnaire used in this study was derived from this registry’s results and from previously validated questionnaires and addressed 3 domains of importance, namely, provision of information, pain, and interaction with the anesthesiologist. The 11-item written, multidimensional questionnaire was given to patients within 2 days postoperatively. The primary outcome was willingness to have PNB repeated in the event of future similar surgery. Results Data related to 9969 surgical procedures were collected between July 1, 2011, and March 31, 2013. The survey response rate was 61.6%. Most respondents—94.6% (95% confidence interval, 94.0%–95.1%)—stated that they were willing to have a repeat PNB. Ninety percent of respondents were satisfied or completely satisfied with the information provided about the nerve block, as well as the anesthesiologist-patient interaction. Patients who were dissatisfied with either of these domains (ie, information provision or professional interaction) were less willing to undergo repeat PNB, as were patients who reported significant pain during the nerve block procedure. Conclusions A high proportion of survey respondents were willing to undergo repeat PNB in case of future surgery and were satisfied with their anesthetic care. Targeted interventions to improve quality of PNB should be aimed at improving comfort, information provision, and physician-patient interaction.

Evaluation of a task-specific checklist and global rating scale for ultrasound-guided regional anesthesia.

Background and Objectives Checklists and global rating scales (GRSs) are used for assessment of anesthesia procedural skills. The purpose of this study was to evaluate the reliability and validity of a recently proposed assessment tool comprising a checklist and GRS specific for ultrasound-guided regional anesthesia. Methods In this prospective, fully crossed study, we videotaped 30 single-target nerve block procedures performed by anesthesia trainees. Following pilot assessment and observer training, videos were assessed in random order by 6 blinded, expert observers. Interrater reliability was evaluated with intraclass correlation coefficients (ICCs) based on a 2-way random-effects model that took into account both agreement and correlation between observer results. Construct validity and feasibility were also evaluated. Results The ICC between assessors’ total scores was 0.44 (95% confidence interval, 0.27–0.62). All 6 observers scored “experienced trainees” higher than “inexperienced trainees” (median total score 76.7 vs 54.2, P = 0.01), supporting the test’s construct validity. The median time to assess the videos was 4 minutes 29 seconds. Conclusions This is the first study to evaluate the reliability and validity of a combined checklist and GRS for ultrasound-guided regional anesthesia using multiple observers and taking into account both absolute agreement and correlation in determining the ICC of 0.44 for interrater reliability. There was evidence to support construct validity.