Thomas Anderson, MD, PhD

Abstract

Ex vivo rodent whole nerves provide a model for assessing the effects of interventions on nerve impulse transmission and consequent sensory and/or motor function. Nerve impulse transmission can be measured through sciatic nerve compound action potential (CAP) recordings. However, de novo development and implementation of an ex vivo whole nerve resection protocol and an electrophysiology setup that retains nerve viability, that produces low noise CAP signals, and that allows for data analysis is challenging. Additionally, some of the existing literature lacks detail and accuracy and may be out of date. This article describes detailedprotocols for rodent ex vivo sciatic nerve dissection and handling; importance of an optimal physiologic solution; computer-aided designs for 3D printing of readily adaptable ex vivo rodent whole nerve electrophysiology chambers; construction of low-cost, effective suction electrodes; setup and use of nerve stimulators and amplifiers; acquisition of low noise, small voltage CAP data and digital conversion; use of software for data analyses of CAP components; and tips for troubleshooting. 2020 Wiley Periodicals LLC. Basic Protocol 1: Electrophysiology wiring and hardware setup Support Protocol 1: 3D printing an electrophysiology chamber Support Protocol 2: Building suction electrodes Basic Protocol 2: Sciatic nerve dissection and compound action potential recording Basic Protocol 3: Data export and analysis Support Protocol 3: Preparation of HEPES-buffered physiologic solution.

View details for DOI 10.1002/cpns.99

View details for PubMedID 32663369

Abstract

There is growing evidence to support the perioperative use of non-opioid analgesic medications in the pediatric population,1 but the use of, and attitudes toward, these agents among pediatric anesthesiologists is unknown. In order to characterize utilization of opioid-sparing agents in pediatric anesthesia, we designed a survey to study usage patterns for several non-opioid adjuncts by members of the Society for Pediatric Anesthesia (SPA) during and in the 24 hours following procedures.

View details for DOI 10.1111/pan.13891

View details for PubMedID 32323361

Abstract

Caudal anesthesia is a common and effective regional anesthesia technique in pediatric patients. The addition of epinephrine to local anesthetics in caudal anesthesia is a frequent practice; however, changes in hemodynamic and cardiac parameters produced by epinephrine in caudal anesthesia are not well studied. Using data collected with the ICON noninvasive cardiac output monitor, we examined the hemodynamic changes associated with the administration of epinephrine containing local anesthetics during caudal anesthesia in children.We performed a retrospective analysis of 40 patients who received caudal anesthesia among 402 patients from whom we prospectively collected continuous noninvasive cardiac output data using the ICON monitor, which estimates cardiac output by measuring changes in thoracic bioimpedance during the cardiac cycle. Twenty-three children received epinephrine with local anesthetic (ELA), and 17 children received only local anesthetic (OLA) in their caudal blocks. We compared heart rate (HR), stroke volume (SV), cardiac output (CO), and cardiac index (CI) changes from baseline before caudal injection to 1-minute intervals over 15 minutes after caudal injection for both ELA and OLA groups (Table, Supplemental Digital Content 1, http://links.lww.com/AAP/A179). We also performed subgroup analysis of the same parameters comparing both ELA and OLA groups in infants younger than 6 months and in children 6 months or older.Stroke volume, CO, and CI are significantly increased after caudal injection in the ELA group compared with baseline values at caudal injection time. Conversely, there were no statistically significant changes in SV, CO, and CI in the OLA group. There were no significant HR or blood pressure changes observed in either the ELA or OLA group within 15 minutes compared with baseline caudal injection time. In infants younger than 6 months, no significant differences were found in HR, SV, and CI in children in the ELA group compared with the OLA group. In children 6 months or older, SV and CI increased significantly in the ELA group compared with the OLA group.Epinephrine added to local anesthetic injected for caudal anesthesia produces significant increases in SV, CO, and CI in children. Stroke volume and CI changes from epinephrine added to local anesthetic for caudal anesthesia seem to take place only in children 6 months or older.

View details for DOI 10.1097/AAP.0000000000000498

View details for PubMedID 27755489

View details for DOI 10.1016/j.bja.2020.11.003

View details for PubMedID 33256991

Abstract

BACKGROUND: This study evaluated the association between neuromuscular blocking agent dose and postoperative respiratory complications in infants and children.METHODS: Data from 6507 general anaesthetics provided to children 10 years undergoing surgery were analysed to examine the effects of neuromuscular blocking agent dose on postoperative respiratory complications (primary endpoint) and secondary endpoints. Confounder-adjusted analyses addressed age, surgical duration, and comorbidity burden.RESULTS: In confounder-adjusted analyses, high doses of neuromuscular blocking agents were associated with higher risk of postoperative respiratory complications (OR 2.27; 95%CI 1.12-4.59; P=0.022). The effect was modified by age (P-for-interaction=0.016) towards a more substantial risk in infants 1 year (OR 3.84; 95%CI 1.35-10.94; P=0.012), by duration of surgery (P-for-interaction=0.006) towards a higher difference in odds for surgeries <90mins (OR 4.25; 95%CI 1.19-15.18; P=0.026), and by ASA physical status (P-for-interaction=0.015) with a greater effect among patients with higher operative risk (ASA >1: OR 3.17; 95%CI 1.43-7.04; P=0.005). Neostigmine reversal did not modify the association between neuromuscular blocking agents and postoperative respiratory complications (P-for-interaction =0.38). Instrumental variable analysis confirmed that high doses of neuromuscular blocking agents were associated with postoperative respiratory complications (probit coefficient 0.25, 95%CI 0.04-0.46; P=0.022), demonstrating robust results regarding concerns of unobserved confounding.CONCLUSIONS: High dose of neuromuscular blocking agents is associated with postoperative respiratory complications. We have identified subcohorts of paediatric patients who are particularly vulnerable to the respiratory side-effects of neuromuscular blocking agents: infants, paediatric patients undergoing surgeries of short duration, and those with a high ASA risk score.

View details for DOI 10.1111/aas.13478

View details for PubMedID 31529484

View details for DOI 10.1097/AJP.0000000000000702

View details for Web of Science ID 000467737200002

Abstract

Wide variability persists in the preparation and storage of common anesthetic medications despite the recognition of anesthesia workspace standardization as a national quality improvement priority. Syringe contamination and medication swaps continue to pose significant hazards to patient safety.We assessed differences in practice related to the availability of commonly prepared anesthetic medications. Using baseline provider surveys (n=87) and anesthesia workspace audits (n=80), we designed a custom syringe organization device using 3D printing techniques to serve as a cognitive aid and organizational tool. We iteratively tested and then deployed this device in all 60 operating rooms at a single institution, and then, repeated postintervention surveys (n=79) and workspace audits (n=75) one year after introduction.Implementation was associated with significant improvements in provider-reported medication availability during coverage and handoff situations (43.7% versus 76.2% reporting 95% confidence preintervention versus postintervention, p < 0.001). This was substantiated by audits of the anesthesia workspace which demonstrated reduced variability in the location (p < 0.001) and availability (p < 0.001) of key medications. Provider confidence in the cleanliness of syringes was also improved (p=0.01). A high degree of acceptance and compliance with the intervention was reported, with 80.4% of syringes observed to be stored in the device one year after implementation and approximately 95% of respondents reporting positive measures of usability and convenience.Use of a simple organizational device for syringes in the anesthesia workspace has numerous safety benefits. 3D printing offers improvements in adaptability and affordability compared with prior approaches.

View details for DOI 10.1155/2019/2673781

View details for PubMedID 31354811

View details for PubMedCentralID PMC6636519

Abstract

Maintaining a balance between nociception and analgesia perioperatively reduces morbidity and improves outcomes. Current intraoperative analgesic strategies are based on subjective and nonspecific parameters. The high-frequency heart rate (HR) variability index is purported to assess the balance between nociception and analgesia in patients under general anesthesia. This prospective observational study investigated whether intraoperative changes in the high-frequency HR variability index correlate with clinically relevant nociceptive stimulation and the addition of analgesics.Instantaneous and mean high-frequency HR variability indexes were measured continuously in 79 adult subjects undergoing general anesthesia for laparoscopic cholecystectomy. The indexes were compared just before and 2 minutes after direct laryngoscopy, orogastric tube placement, first skin incision, and abdominal insufflation and just before and 6 minutes after the administration of IV hydromorphone.Data from 65 subjects were included in the final analysis. The instantaneous index decreased after skin incision ([SEM], 58.7 [2.0] vs 47.5 [2.0]; P < .001) and abdominal insufflation (54.0 [2.0] vs 46.3 [2.0]; P = .002). There was no change in the instantaneous index after laryngoscopy (47.2 [2.2] vs 40.3 [2.3]; P = .026) and orogastric tube placement (49.8 [2.3] vs 45.4 [2.0]; P = .109). The instantaneous index increased after hydromorphone administration (58.2 [1.9] vs 64.8 [1.8]; P = .003).In adult subjects under general anesthesia for laparoscopic cholecystectomy, changes in the high-frequency HR variability index reflect alterations in the balance between nociception and analgesia. This index might be used intraoperatively to titrate analgesia for individual patients. Further testing is necessary to determine whether the intraoperative use of the index affects patient outcomes.

View details for DOI 10.1213/ANE.0000000000004180

View details for PubMedID 31008745

Abstract

Racial and ethnic disparities in health care are well documented in the United States, although evidence of disparities in pediatric anesthesia is limited. We sought to determine whether there is an association between race and ethnicity and the use of intraoperative regional anesthesia at a single academic children's hospital.We performed a retrospective review of all anesthetics at an academic tertiary children's hospital between May 4, 2014, and May 31, 2018. The primary outcome was delivery of regional anesthesia, defined as a neuraxial or peripheral nerve block. The association between patient race and ethnicity (white non-Hispanic or minority) and receipt of regional anesthesia was assessed using multivariable logistic regression. Sensitivity analyses were performed comparing white non-Hispanic to an expansion of the single minority group to individual racial and ethnic groups and on patients undergoing surgeries most likely to receive regional anesthesia (orthopedic and urology patients).Of 33,713 patient cases eligible for inclusion, 25,664 met criteria for analysis. Three-thousand one-hundred eighty-nine patients (12.4%) received regional anesthesia. One thousand eighty-six of 8884 (13.3%) white non-Hispanic patients and 2003 of 16,780 (11.9%) minority patients received regional anesthesia. After multivariable adjustment for confounding, race and ethnicity were not found to be significantly associated with receiving intraoperative regional anesthesia (adjusted odds ratios [ORs] = 0.95; 95% confidence interval [CI], 0.86-1.06; P = .36). Sensitivity analyses did not find significant differences between the white non-Hispanic group and individual races and ethnicities, nor did they find significant differences when analyzing only orthopedic and urology patients, despite observing some meaningful clinical differences.In an analysis of patients undergoing surgical anesthesia at a single academic children's hospital, race and ethnicity were not significantly associated with the adjusted ORs of receiving intraoperative regional anesthesia. This finding contrasts with much of the existing health care disparities literature and warrants further study with additional datasets to understand the mechanisms involved.

View details for DOI 10.1213/ANE.0000000000004456

View details for PubMedID 31569162

Abstract

The retrolaminar block (RB) is used for truncal analgesia, but its mechanism of neural blockade remains obscure. We sought to learn the pattern of local anesthetic spread after thoracic RB using cadaveric models.In 8 fresh cadavers, an ultrasound-guided T4 RB was performed with 20 mL of methylene blue 1% and bupivacaine 0.5%. For comparison, an RB at T9 in 1 cadaver and a T4 thoracic paravertebral block in another cadaver were performed. Subsequently, posterior and anterior thoracic dissections were performed to examination where the dye spread.After T4 RB, dye was noted to spread in the ipsilateral retrolaminar plane (all 8 cadavers, median cephalad spread 3.5 cm, caudad spread 10.7 cm, lateral spread 2.5 cm), the contralateral retrolaminar plane (6 cadavers), the paravertebral space (5 cadavers, median of 3 segments, T3-T5), the intercostal space (5 cadavers, median of 3.5 cm laterally), the T4 epidural space (6 cadavers), and the intervertebral foramina (4 cadavers, median of 2 segments, T4-T5). After T9 retrolaminar injection, dye was noted in the ipsilateral retrolaminar plane (5.5 cm cephalad, 13.5 cm caudad, and 2.5 cm lateral), the contralateral retrolaminar plane, and the epidural space. Dye after T4 traditional paravertebral block spread to T1-T6 paravertebral space with 15-cm lateral spread.Injectate spread to the paravertebral space, epidural space, intercostal space, and intervertebral foramina is possible in the RB but is quite variable. In comparison to the thoracic paravertebral block, injectate spread within the paravertebral space is more limited.

View details for PubMedID 29923954

Abstract

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Complications in pediatric regional anesthesia are rare, so a large sample size is necessary to quantify risk. The Pediatric Regional Anesthesia Network contains data on more than 100,000 blocks administered at more than 20 children's hospitals. This study analyzed the risk of major complications associated with regional anesthesia in children.METHODS: This is a prospective, observational study of routine clinical practice. Data were collected on every regional block placed by an anesthesiologist at participating institutions and were uploaded to a secure database. The data were audited at multiple points for accuracy.RESULTS: There were no permanent neurologic deficits reported (95% CI, 0 to 0.4:10,000). The risk of transient neurologic deficit was 2.4:10,000 (95% CI, 1.6 to 3.6:10,000) and was not different between peripheral and neuraxial blocks. The risk of severe local anesthetic systemic toxicity was 0.76:10,000 (95% CI, 0.3 to 1.6:10,000); the majority of cases occurred in infants. There was one epidural abscess reported (0.76:10,000, 95% CI, 0 to 4.8:10,000). The incidence of cutaneous infections was 0.5% (53:10,000, 95% CI, 43 to 64:10,000). There were no hematomas associated with neuraxial catheters (95% CI, 0 to 3.5:10,000), but one epidural hematoma occurred with a paravertebral catheter. No additional risk was observed with placing blocks under general anesthesia. The most common adverse events were benign catheter-related failures (4%).CONCLUSIONS: The data from this study demonstrate a level of safety in pediatric regional anesthesia that is comparable to adult practice and confirms the safety of placing blocks under general anesthesia in children.

View details for PubMedID 30074928

View details for Web of Science ID 000460106500255

Abstract

Esmolol is an ultrashort -1 receptor antagonist. Recent studies suggest a role for esmolol in pain response modulation. The authors performed a meta-analysis to determine if the intraoperative use of esmolol reduces opioid consumption or pain scores.PubMed, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, pubget, and Google Scholar were searched. Studies were included if they were randomized, placebo- or opioid-controlled trials written in English, and performed on patients 18 years of age or older. For comparison of opioid use, included studies tracked opioid consumption intraoperatively and/or in the postanesthesia care unit. Pain score comparisons were performed during the first hour after surgery.Seventy-three studies were identified, 23 were included in the systematic review, and 19 were eligible for 1 or more comparisons. In 433 patients from 7 trials, intraoperative esmolol decreased intraoperative opioid consumption (Standard Mean Difference [SMD], -1.60; 95% confidence interval [CI], -2.25 to -0.96; P .001). In 659 patients from 12 trials, intraoperative esmolol decreased postanesthesia care unit opioid consumption (SMD, -1.21; 95% CI, -1.66 to -0.77; P .001). In 688 patients from 11 trials, there was insufficient evidence of change in postoperative 1 hour pain scores (SMD, -0.60; 95% CI, -1.44 to 0.24; P = .163).This meta-analysis demonstrates that intraoperative esmolol use reduces both intraoperative and postoperative opioid consumption, with no change in postoperative pain scores.

View details for DOI 10.1213/ANE.0000000000002469

View details for Web of Science ID 000425343900041

View details for PubMedID 29028742

Abstract

Orthotopic liver transplantation (OLT) is characterized by significant intraoperative hemodynamic variability. Accurate and real-time cardiac output (CO) monitoring aids clinical decision making during OLT. The purpose of this study is to compare accuracy, precision, and trending ability of CO estimation obtained noninvasively using pulse wave transit time (estimated continuous cardiac output [esCCO; Nihon Kohden, Tokyo, Japan]) or thoracic bioimpedance (ICON; Osypka Medical GmbH, Berlin, Germany) to thermodilution cardiac output (TDCO) measured with a pulmonary artery catheter.Nineteen patients undergoing OLT were enrolled. CO measurements were collected with esCCO, ICON, and thermodilution at 5 time points: (T1) pulmonary artery catheter insertion; (T2) surgical incision; (T3) portal reperfusion; (T4) hepatic arterial reperfusion; and (T5) abdominal closure. The results were analyzed with Bland-Altman plot, percentage error (the percentage of the difference between the CO estimated with the noninvasive monitoring device and CO measured with the thermodilution technique), 4-quadrant plot with concordance rate (the percentage of the total number of points in the I and III quadrant of the 4-quadrant plot), and concordance correlation coefficient (a measure of how well the pairs of observations deviate from the 45-degree line of perfect agreement).Although TDCO increased at T3-T5, both esCCO and ICON failed to track the changes of CO with sufficient accuracy and precision. The mean bias of esCCO and ICON compared to TDCO were -2.0 L/min (SD, 2.7 L/min) and -3.3 L/min (SD, 2.8 L/min), respectively. The percentage error was 69% for esCCO and 77% for ICON. The concordance correlation coefficient was 0.653 (95% confidence interval [CI], 0.283-0.853) for esCCO and 0.310 (95% CI, -0.167 to 0.669) for ICON. Nonetheless, esCCO and ICON exhibited reasonable trending ability of TDCO (concordance rate: 95% [95% CI, 88-100] and 100% [95% CI, 93-100]), respectively. The mean bias was correlated with systemic vascular resistance (SVR) and arterial elastance (Ea) for esCCO (SVR, r = 0.610, 95% CI, 0.216-0.833, P < .0001; Ea, r = 0.692, 95% CI, 0.347-0.872; P < .0001) and ICON (SVR, r = 0.573, 95% CI, 0.161-0.815, P < .0001; Ea, r = 0.612, 95% CI, 0.219-0.834, P < .0001).The noninvasive CO estimation with esCCO and ICON exhibited limited accuracy and precision, despite with reasonable trending ability, when compared to TDCO, during OLT. The inaccuracy of esCCO and ICON is especially large when SVR and Ea were decreased during the neohepatic phase. Further refinement of the technology is desirable before noninvasive techniques can replace TDCO during OLT.

View details for DOI 10.1213/ANE.0000000000002171

View details for PubMedID 28598912

Abstract

Regional anesthesia has been used to help create local sympathectomy and improve blood flow in plastic surgery procedures involving tissue grafts and flaps. However, anesthetic techniques that reduce systemic vascular resistance must be used with caution in patients with aortic stenosis (AS). Combined neuraxial and general anesthesia with careful titration of the local anesthetic dose can be a safe approach for patients with AS undergoing microvascular procedures. We present the anesthetic management of the first North American penile transplant, on an obese patient with moderate AS.

View details for DOI 10.1213/XAA.0000000000000672

View details for PubMedID 29708917

Abstract

Heart rate variability (HRV) is a measure of the balance between both the parasympathetic and sympathetic nervous system and may provide useful information for anesthesia care providers. HRV may offer predictive information about critically ill and operative patients. Further, HRV collection provides real-time information of patient autonomic nervous system status and may allow tailoring of the analgesia for patients in the ICU and operating room.Reduced and abnormal resting HRV predict sudden and nonsudden cardiac death. Recent evidence shows that decreased HRV correlates with worsened outcomes in both trauma patients and patients with sepsis, as well as the risk of developing hypotension after induction of general anesthesia and placement of intrathecal local anesthesia. In addition, HRV appears to provide an accurate assessment of the nociception-analgesia balance in deeply sedated ICU patients and those under general anesthesia.No study has assessed the prognostic value of preoperative HRV in patients presenting for surgery. Use of HRV for patient risk stratification and intraoperative analgesia management may allow tailored perioperative care and improved outcomes. If intraoperative HRV data leads to decreased perioperative opioid use, opioid-related adverse events, a serious perioperative issue, may be decreased.Not applicable.

View details for PubMedID 28957877

Abstract

While a large number of studies has examined the efficacy of opioid-sparing analgesics in adult surgical populations, fewer studies are available to guide postoperative pain treatment in pediatric patients. We systematically reviewed available publications on the use of systemic nonopioid agents for postoperative analgesia in pediatric surgical populations. A comprehensive literature search identified meta-analyses and randomized controlled trials (RCTs) assessing the effects of systemic, nonopioid agents on postoperative narcotic requirements or pain scores in pediatric surgical populations. If a meta-analysis was located, we summarized its results and any RCTs published after it. We located and reviewed 11 acetaminophen RCTs, 1 nonsteroidal anti-inflammatory drug (NSAID) meta-analysis, 2 NSAID RCTs, 1 dexamethasone meta-analysis, 3 dexamethasone RCTs, 2 ketamine meta-analyses, 5 ketamine RCTs, 2 gabapentin RCTs, 1 clonidine meta-analysis, 3 magnesium RCTs, 2 dexmedetomidine meta-analyses, and 1 dextromethorphan RCT. No meta-analyses or RCTs were found assessing the perioperative efficacy of intravenous lidocaine, amantadine, pregabalin, esmolol, or caffeine in pediatric surgical patients. The available evidence is limited, but suggests that perioperative acetaminophen, NSAIDs, dexamethasone, ketamine, clonidine, and dexmedetomidine may decrease postoperative pain and opioid consumption in some pediatric surgical populations. Not enough, or no, data exist from which to draw conclusions on the perioperative use of gabapentin, magnesium, dextromethorphan, lidocaine, amantadine, pregabalin, esmolol, and caffeine in pediatric surgical patients. Further pharmacokinetic and pharmacodynamics studies to establish both the clinical benefit and efficacy of nonopioid analgesia in pediatric populations are needed.

View details for DOI 10.1213/ANE.0000000000002434

View details for PubMedID 29049110

View details for DOI 10.1097/ALN.0000000000001633

View details for PubMedID 28511196

View details for DOI 10.4097/kjae.2017.70.6.652

View details for PubMedID 29225750

View details for PubMedCentralID PMC5716825

Abstract

N-methyl-D-aspartate receptor antagonists have been shown to reduce perioperative pain and opioid use. The authors performed a meta-analysis to determine whether the use of perioperative dextromethorphan lowers opioid consumption or pain scores.PubMed, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Pubget, and EMBASE were searched. Studies were included if they were randomized, double-blinded, placebo-controlled trials written in English, and performed on patients 12 yr or older. For comparison of opioid use, included studies tracked total consumption of IV or intramuscular opioids over 24 to 48 h. Pain score comparisons were performed at 1, 4 to 6, and 24 h postoperatively. Difference in means (MD) was used for effect size.Forty studies were identified and 21 were eligible for one or more comparisons. In 848 patients from 14 trials, opioid consumption favored dextromethorphan (MD, -10.51 mg IV morphine equivalents; 95% CI, -16.48 to -4.53 mg; P = 0.0006). In 884 patients from 13 trials, pain at 1 h favored dextromethorphan (MD, -1.60; 95% CI, -1.89 to -1.31; P < 0.00001). In 950 patients from 13 trials, pain at 4 to 6 h favored dextromethorphan (MD, -0.89; 95% CI, -1.11 to -0.66; P < 0.00001). In 797 patients from 12 trials, pain at 24 h favored dextromethorphan (MD, -0.92; 95% CI, -1.24 to -0.60; P < 0.00001).This meta-analysis suggests that dextromethorphan use perioperatively reduces the postoperative opioid consumption at 24 to 48 h and pain scores at 1, 4 to 6, and 24 h.

View details for DOI 10.1097/ALN.0000000000000950

View details for PubMedID 26587683

View details for PubMedCentralID PMC4755866

View details for DOI 10.1097/AIA.0000000000000095

View details for PubMedID 26967805

Abstract

Neuraxial anesthesia and epidural steroid injection techniques require precise anatomical targeting to ensure successful and safe analgesia. Previous studies suggest that only some of the tissues encountered during these procedures can be identified by spectroscopic methods, and no previous study has investigated the use of Raman, diffuse reflectance, and fluorescence spectroscopies. The authors hypothesized that real-time needle-tip spectroscopy may aid epidural needle placement and tested the ability of spectroscopy to distinguish each of the tissues in the path of neuraxial needles.For comparison of detection methods, the spectra of individual, dissected ex vivo paravertebral and neuraxial porcine tissues were collected using Raman spectroscopy (RS), diffuse reflectance spectroscopy, and fluorescence spectroscopy. Real-time spectral guidance was tested using a 2-mm inner-diameter fiber-optic probe-in-needle device. Raman spectra were collected during the needle's passage through intact paravertebral and neuraxial porcine tissue and analyzed afterward. The RS tissue signatures were verified as mapping to individual tissue layers using histochemical staining and widefield microscopy.RS revealed a unique spectrum for all ex vivo paravertebral and neuraxial tissue layers; diffuse reflectance spectroscopy and fluorescence spectroscopy were not distinct for all tissues. Moreover, when accounting for the expected order of tissues, real-time Raman spectra recorded during needle insertion also permitted identification of each paravertebral and neuraxial porcine tissue.This study demonstrates that RS can distinguish the tissues encountered during epidural needle insertion. This technology may prove useful during needle placement by providing evidence of its anatomical localization.

View details for DOI 10.1097/ALN.0000000000001249

View details for PubMedID 27466032

View details for PubMedCentralID PMC5030194

Abstract

To assess the effects of desaturation on stroke index (SI), cardiac index (CI), and heart rate (HR) using the ICON continuous noninvasive cardiac output monitor in children undergoing general anesthesia.Retrospective analysis of a prospectively collected data set.Pediatric operating rooms in a tertiary academic medical center.Children younger than 20 years who experienced desaturation while undergoing general anesthesia.All records were retrospectively searched for desaturation events defined as a recorded Spo2 90%. We compared the data from the prior 4 minutes (baseline) with mild, moderate, and severe levels of desaturation.The relationship between Spo2 and percent change in SI, CI, and HR from baseline was assessed using a generalized linear model with repeated measures and the least-squares method.Data from 446 patients were reviewed; 38 events were eligible for analysis after exclusions. There were significant decreases in SI at all saturation ranges below 95%: -6.5% (P < .001) for 85%-95%, -8.9% (P = .002) for 71%-84%, and -11% (P < .001) for 70%. Based on the result from the regression, Spo2 was associated with change in SI with borderline significance (P = .053) but not that of HR and CI. There was a strong relationship to desaturation events with young age (P < .001), particularly infants younger than 6 months.Events associated with desaturation in children under general anesthesia were significantly associated with decreased SI with a greater effect with lower saturation nadirs. It is unclear if other concurrent events could have also contributed to adverse hemodynamic responses during desaturation. In most children, a compensatory increase in HR generally offsets concurrent decreases in CI. It would appear that bradycardia is a late manifestation of hypoxemia.

View details for DOI 10.1016/j.jclinane.2016.02.026

View details for PubMedID 27290971

Abstract

We hypothesized that anesthetized, apneic children could be ventilated equivalently or more efficiently by nasal mask ventilation (NMV) than face mask ventilation (FMV). The aim of this randomized controlled study was to test this hypothesis by comparing the expiratory tidal volume (Vte) between NMV and FMV.After the induction of anesthesia, 41 subjects, 3-17 years of age without anticipated difficult mask ventilation, were randomly assigned to receive either NMV or FMV with neck extension. Both groups were ventilated with pressure control ventilation (PCV) at 20 cmH2 O of peak inspiratory pressure (PIP) with positive end-expiratory pressure (PEEP) levels of 0, 5, and 10 cmH2 O. An additional mouth closing maneuver (MCM) was applied for the NMV group.The Vte was higher in the FMV group compared with the NMV group (median difference [95% CI]: 8.4 [5.5-11.6] mlkg(-1) ; P < 0.001) when MCM was not applied. NMV achieved less PEEP than FMV (median difference [95% CI]: 5.0 [4.3-5.3] cmH2 O at 10 cmH2 O; P < 0.001) though both groups achieved the set PIP level. In the NMV group, MCM markedly increased Vte (median increase [95% CI]: 5.9 [2.5-9.0] mlkg(-1) ; P < 0.005) and PEEP (median increase [95% CI]: 5.0 [0.6-8.6] cmH2 O at 10 cmH2 O; P < 0.005); however, PEEP was highly variable and lower than that of FMV (median difference [95% CI]: 2.5 [0.8-8.5] cmH2 O at 10 cmH2 O; P < 0.05).In anesthetized, apneic children greater than 2 years of age ventilated with an anesthesia ventilator and neck extension, FMV established a greater Vte than NMV regardless of mouth status. NMV could not maintain the set PEEP level due to an air leak from the mouth. The MCM increased the Vte and PEEP.

View details for DOI 10.1111/pan.12822

View details for PubMedID 26725988

Abstract

Electrical Cardiometry() (EC) estimates cardiac parameters by measuring changes in thoracic electrical bioimpedance during the cardiac cycle. The ICON(), using four electrocardiogram electrodes (EKG), estimates the maximum rate of change of impedance to peak aortic blood acceleration (based on the premise that red blood cells change from random orientation during diastole (high impedance) to an aligned state during systole (low impedance)).To determine whether continuous cardiac output (CO) data provide additional information to current anesthesia monitors that is useful to practitioners.After IRB approval and verbal consent, 402 children were enrolled. Data were uploaded to our anesthesia record at one-minute intervals. Ten-second measurements (averaged over the previous 20 heart beats) were downloaded to separate files for later comparison with routine OR monitors.Data from 374 were in the final cohort (loss of signal or improper lead placement); 292,012 measurements during 58,049 min of anesthesia were made in these children (1 day to 19 years and 1 to 107 kg). Four events had a 25% reduction in cardiac index at least 1 min before a clinically important change in other monitored parameters; 18 events in 14 children confirmed manifestations of other hemodynamic measures; eight events may have represented artifacts because the observed measurements did not seem to fit the clinical parameters of the other monitors; three other events documented decreased stroke index with extreme tachycardia.Electrical cardiometry provides real-time cardiovascular information regarding developing hemodynamic events and successfully tracked the rapid response to interventions in children of all sizes. Intervention decisions must be based on the combined data from all monitors and the clinical situation. Our experience suggests that this type of monitor may be an important addition to real-time hemodynamic monitoring.

View details for DOI 10.1111/pan.12441

View details for PubMedID 24916144

Abstract

While a few publications specify the anesthetic implications of either brain or cardiac death, they lack detail on how to provide anesthesia during organ donation surgery. We provide a thorough description of important anesthetic considerations during organ donation surgery in patients with either brain or cardiac death.A thorough literature review was undertaken to locate all relevant articles that describe systemic effects of brain and cardiac death and their anesthetic implications. We searched PubMed, Pubget, and EMBASE for relevant articles using the following search terms: anesthesia, management, donation cardiac death, donation brain death. In addition, we reviewed the relevant protocols at our own institution.Highly specific intraoperative management by an anesthesiologist is required during organ procurement after brain death. To manage the heart-beating brain-dead donor, the anesthesiologist must incorporate knowledge of the effects of brain death on each organ system as well as the effects of the preoperative measures that the donor required in the intensive care unit. It is also important to know which organs are going to be procured in order to establish specific goals and implement strategies (e.g., lung-protective ventilation or intraoperative glycemic control) to optimize donor outcome. During organ procurement after cardiac death, an anesthesiologist's direct involvement is particularly important for lung donors.Anesthesiologist-guided physiological optimization of the brain-dead donor may be a factor in determining the outcome of the organ recipient. Additionally, anesthesiologists have an important role in helping to ensure that the highest quality and most appropriate care are rendered to non-heart-beating donors. This is achieved through establishing protocols in their hospitals for donation after cardiac death that maximize the number of available organs with the best chance for long-term graft viability.

View details for DOI 10.1007/s12630-015-0345-8

View details for PubMedID 25715847

Abstract

Status asthmaticus is an acute, intractable asthma attack refractory to standard interventions that can lead to progressive respiratory failure. Successful management requires a fundamental understanding of the disease process, its clinical presentation, and proper evaluation. Treatment must be instituted early and is aimed at reversing the airway inflammation, bronchoconstriction, and hyper-reactivity that often lead to lower airway obstruction, impaired ventilation, and oxygenation. Most patients are effectively treated with standard therapy including beta2-adrenergic agonists and corticosteroids. Others necessitate adjunctive therapies and escalation to noninvasive ventilation or intubation. We will review the pathophysiology, evaluation, and treatment options for pediatric patients presenting with status asthmaticus with a particular focus on refractory status asthmaticus treated with volatile anesthetics. In addition, we include a proven approach to the management of these patients in the critical care setting, which requires close coordination between critical care and anesthesia providers. We present a case series of three patients, two of which have the longest reported cases of continuous isoflurane use in status asthmaticus. This series was obtained from a retrospective chart review and highlights the efficacy of the volatile anesthetic, isoflurane, in three pediatric patients with refractory life-threatening status asthmaticus.

View details for DOI 10.1111/pan.12577

View details for PubMedID 25580870

Abstract

Arthrogryposis is characterized by multiple, nonprogressive joint contractures which may be caused by maternal disorders such as oligohydramnios as well as fetal akinesia resulting from primary disorders of muscle, connective tissue, or neurologic tissue. Its prevalence is about 1 : 3000. Distal arthrogryposis (DA) is a heterogenous group of genetic disorders with a characteristic flexion of the joints of the hands and feet divided into different types with additional features. Sheldon-Hall Syndrome (SHS), also known as distal arthrogryposis type 2A (DA2A), has some nonorthopedic features of specific importance to anesthetic care.

View details for DOI 10.1111/pan.12303

View details for PubMedID 24829975

Abstract

Burn patients provide numerous challenges to the anesthesiologist. It is important to understand the multiple physiologic disruptions that follow a burn injury as well as the alterations in pharmacokinetics and pharmacodynamics of commonly used anesthetics. Thought must be given to surgery during initial fluid resuscitation and the airway challenges many of these patients present. Finally, the central role of pain management through all phases of care is a constant concern.

View details for DOI 10.1016/j.suc.2014.05.008

View details for PubMedID 25085092

Abstract

We describe using ultrasound-guided peripheral nerve blocks for postoperative pain control in 2 children undergoing ventricular shunt surgery. In the first patient undergoing ventriculo-peritoneal shunt revision, a combination of ultrasound-guided greater occipital nerve, superficial cervical plexus, and transversus abdominis plane blocks was used. In the second patient undergoing ventriculo-pleural shunt revision, a combination of ultrasound-guided greater occipital nerve, superficial cervical plexus, and intercostal blocks was used. Both patients, who underwent multiple revisions during their hospitalizations, showed decreased analgesic requirements after regional anesthesia. Our experience suggests this combined block technique may provide beneficial postoperative analgesia for patients undergoing shunt revision.

View details for DOI 10.1213/XAA.0000000000000109

View details for PubMedID 25612197

Abstract

Over the last 6 decades, organ transplantation has achieved great success to become standard therapy for the treatment of patients with end-stage organ failure. With this success has emerged candidate wait lists that greatly outnumber the current supply of deceased donor organs. The increasing number of candidates and transplants performed has resulted in an organ allocation process that occurs at a local, regional, and sometimes national level. A brief description of the history is presented as well as the methodologies involved in allocation of a donor organ to a single recipient.

View details for DOI 10.1016/j.anclin.2013.08.002

View details for PubMedID 24287345

Abstract

The Arc repressor of bacteriophage P22 is a dimeric member of the ribbon-helix-helix family of transcription factors. Residues 9-14 of each wild-type Arc subunit pair to form two antiparallel beta-strands and have the alternating pattern of polar and nonpolar residues expected for a beta-ribbon with one solvent-exposed face and one face that forms part of the hydrophobic core. Simultaneously switching Asn-11 to Leu and Leu-12 to Asn changes the local binary sequence pattern to that of an amphipathic helix. Previous studies have shown that this double mutation results in replacement of the wild-type beta-ribbon by two right-handed 3(10)-helices. Moreover, an Arc variant bearing just the Asn-11 --> Leu mutation has an ambiguous binary pattern and can form either the ribbon or the helical structures, which interchange rapidly. Here, we study Arc mutants in which position 11 is occupied by Gly, Ala, Val, Ile, Leu, Met, Phe, or Tyr. These mutants adopt the wild-type beta-ribbon structure in a sequence context that stabilizes this fold, but they assume the alternative helical structure in a sequence background in which the wild-type fold is precluded by negative design. In an otherwise wild-type sequence background, the detailed chemical properties of the position 11 side chain dictate which of the two competing conformational folds is preferred.

View details for DOI 10.1073/pnas.0509349102

View details for PubMedID 16344489

View details for PubMedCentralID PMC1317976

Abstract

The Arc repressor of bacteriophage P22 is a member of the ribbon-helix-helix family of transcription factors. Ser32 is a solvent-exposed position that serves a structural role as the N(cap) residue of alpha-helix B of Arc, but also serves a functional role because its side chain is packed close to the sugar-phosphate DNA backbone in the repressor-operator complex. The tolerance of this N(cap) position to amino-acid substitutions was probed by determining the repressor activity in vivo, the thermal stability and the operator-binding activity in vitro of a set of 13 mutant proteins. The stability of position-32 Arc variants, except for Cys32, correlated well with the frequencies observed for the corresponding residues at N(cap) positions in alpha-helices of other proteins. Cysteine was quite stabilizing at the helix-B N(cap) position in Arc, but surprisingly was the least frequent N(cap) residue in the protein database. This latter finding may reflect a hyper-reactivity of N(cap) cysteines, which makes them prone to chemical modification. In general, only Arc variants with small, uncharged residues at position 32 were active in vivo or showed strong operator binding in vitro. Based upon the results presented here, revised sequence alignments of the MetJ and NikR subfamilies with Arc and other ribbon-helix-helix proteins are proposed.

View details for DOI 10.1016/s0301-4622(02)00291-0

View details for PubMedID 12646376