Regional Anesthesia: Preferred Technique for Venodilatation in the Creation of Upper Extremity Arteriovenous Fistulae

International survey of radiocephalic arteriovenous fistula: ISRAF survey

AIMS

The objective of this survey was to encompass the full scope of international practice, entailing all technical, non-technical, preoperative stratification and functional maturation (FM) of RCAVF.

METHODS

The survey contained n = 19 questionnaires with n = 46 variables completed by n = 85 providers from n = 21 nations across n = 5 continents. The numerical values were subjected to mean with standard error whereas the nominal data to a non-parametric (Kruskal-Wallis & Spearman correlation test) and analysis of variance (ANOVA). The test of homogeneity, & probability was reported 95% confidence intervals (CI) alongside error plots. Furthermore, a decision and higher attribute tree model was constructed based on current survey for higher FM in RCAVF.

RESULTS

FM is independently associated with volume of surgeon per year (procedures performed) (p < 0.01) [High Volume: 73% (95% CI, 68-77%) versus Average volume: 63% (95% CI, 59-66%) vs Low volume: 56% (95% CI, 51-61%)]. FM increased by 8% with every 20 more procedures per group of surgeons on end point of FM. Amongst continents: Australia, America, Asia and South America demonstrated higher FM to Africa & Europe (p < 0.05). UK possessed a lower FM 58% (95% CI, 48-68%) in comparison to the world & Europe respectively [65% (95% CI, 61-70%) vs 61% (95% CI, 58--65%)]. There was a positive causal link between angle of anastomosis at 30-76° (p < 0.01), longitudinal & S-shaped incision & arteriotomy length of 3 & 4 mm to higher FM (p < 0.05).

CONCLUSION

FM in RCAVF is independently & incrementally associated with the volume of surgeon per year. There is a diverse inclusion, exclusion and technical approach in RCAVF creation. This survey advocates the importance of international collaboration and/or registry in assimilation, consolidate and development of consensus.

Similar outcomes of arteriovenous fistulae created under general or regional anesthesia

BACKGROUND

There is growing evidence that type of anesthesia can significantly change vascular access surgery outcomes. Still, there is limited evidence on the impact of regional anesthesia (RA) on patency and failure rates compared to general anesthesia (GA). The aim of this study was to compare the outcomes of RA and GA in patients who underwent vascular access creation at our center.

METHODS

Data collected in our prospectively maintained database of patients with chronic renal dysfunction requiring hemodialysis were analyzed, 464 patients were included. Outcome parameters such as maturation, primary failure, postoperative flow measurements, patency rates, and survival outcomes were compared between RA and GA groups.

RESULTS

In this study 489 vascular access procedures were performed in 464 patients, 318 included in the RA group and 171 in the GA group. Median follow-up time was 29.9 (IQR 37.3) months in the RA group versus 33.0 (IQR 40.7) in the GA group (p = 0.252). Anesthesia type did not significantly affect patient survival (HR, 1.01; CI, 0.70-1.45; p = 0.976). No significant differences were found in vascular access flow volume, primary failure, or time to cannulation between the RA and GA groups for both radiocephalic arteriovenous fistulae and brachiocephalic arteriovenous fistulae. Anesthesia type did not significantly change patency outcomes.

CONCLUSIONS

Based on our results, both RA and GA demonstrate similar results regarding patient survival, maturation, failure, or patency after vascular access creation. Still, patient-specific factors for each type of anesthesia as well as patient preference should be considered.

Efficacy of Combined Spinal-Epidural Anesthesia for Lower Extremity Microvascular Reconstruction

INTRODUCTION

Some surgeons have raised concerns regarding the sympathectomy-like effect of epidural anesthesia during lower limb microvascular reconstruction. The combined spinal-epidural (CSE) anesthetic technique incorporates several benefits of spinal and epidural techniques in a single approach. The aim of this study was to analyze the postoperative outcomes of patients undergoing soft-tissue reconstruction of the lower limb by implementing the CSE anesthesia approach.

METHODS

We reviewed medical records from patients who underwent lower limb reconstructive procedures under CSE anesthesia with free tissue transfer from January 2017 to December 2020. We evaluated the postoperative outcomes.

RESULTS

Thirty-eight patients underwent microvascular reconstructive procedures of the lower extremity over the study period. The average age and BMI were 38.4-year and 28 kg/m2. All patients only had one postoperative rescue dose with epidural anesthesia. The most common type of flap used was the anterolateral thigh flap (53%). The average splinting time and length of stay (LoS) were 8.4 days and 18.4 days, respectively. Donor-site complications included wound dehiscence (3%) and surgical site infection (3%). Recipient-site complications included partial flap loss (8%) and total flap loss (10%). No pro re nata morphine analgesia was used. Tramadol and/or ketoprofen were administered for postoperative analgesia. The average time to start physiotherapy and to resume daily activities were 10 days and 29 days, respectively.

CONCLUSIONS

The CSE anesthesia for microvascular reconstruction of the lower limb demonstrated a similar success rate compared to historical records. CSE provided adequate pain management and none of the patients required postoperative monitoring in the ICU.

Small Caliber Distal Cephalic Veins Undergo Significant Dilation under Anesthesia and Can Successfully Be Used for Arteriovenous Fistula Creation

BACKGROUND

Successful arteriovenous fistula (AVF) maturation and use for dialysis is highly dependent on preoperative diameter. Small veins (<2 mm) exhibit high failure rates and are typically avoided. This study investigates the effects of anesthesia on the distal cephalic vein diameter as compared to preoperative outpatient vein mapping for the purpose of hemodialysis access creation.

METHODS

One hundred eight consecutive procedures for dialysis access placement met inclusion criteria and were reviewed. All patients received preoperative venous mapping and postanesthesia ultrasound mapping (PAUS). All patients received either regional and/or general anesthesia. A multiple regression was conducted to determine predictors of venous dilatation. The independent variables included both demographical and operative-specific variables such as the type of anesthesia. Outcomes of fistula maturation (successful cannulation and dialysis) were analyzed.

RESULTS

In this cohort, the mean preoperative vein diameter was 1.85 mm and the mean PAUS diameter was 3.45 mm, a 2.21× increase, with only 2 patient veins failing to increase in diameter. Smaller veins (<2 mm) exhibited significantly more dilation than larger veins after anesthesia (2.73 vs. 1.47×, P < 0.001). In the multiple regression analysis, smaller vein diameter was correlated with a significantly greater degree of dilation (P < 0.001). The degree of venous dilation was not affected by patient demographic-specific factors or by the type of anesthesia (regional block versus general) in the multiple regression analysis. 6 month follow-up data for fistula maturation was available for 75 of 108 patients. Small veins (<2 mm) on preoperative ultrasound matured at a similar rate as larger veins (90% vs. 91.4%, P = 0.833).

CONCLUSIONS

Small caliber distal cephalic veins experience a significant degree of dilation under regional and general anesthesia and can successfully be used for AVF creation. Consideration should be made to perform a postanesthesia vein mapping for all patients undergoing access placement despite preoperative venous mapping results.

Anesthetic choice for arteriovenous access creation: A National Anesthesia Clinical Outcomes Registry analysis

BACKGROUND

We sought to evaluate differences in primary anesthetic type used in arteriovenous access creation with the hypothesis that administration of regional anesthesia and monitored anesthesia care (MAC) with local anesthesia as the primary anesthetic has increased over time.

METHODS

National Anesthesia Clinical Outcomes Registry data were retrospectively evaluated. Covariates were selected a priori within multivariate models to determine predictors of anesthetic type in adults who underwent elective arteriovenous access creation between 2010 and 2018.

RESULTS

A total of 144,392 patients met criteria; 90,741 (62.8%) received general anesthesia. The use of regional anesthesia and MAC decreased over time (8.0%-6.8%, 36.8%-27.8%, respectively; both p < 0.0001). Patients who underwent regional anesthesia were more likely to have ASA physical status >III and to reside in rural areas (52.3% and 12.9%, respectively; both p < 0.0001). Patients who underwent MAC were more likely to be older, male, receive care outside the South, and reside in urban areas (median age 65, 56.8%, 68.1%, and 70.8%, respectively; all p < 0.0001). Multivariate analysis revealed that being male, having an ASA physical status >III, and each 5-year increase in age resulted in increased odds of receiving alternatives to general anesthesia (regional anesthesia adjusted odds ratios (AORs) 1.06, 1.12, and 1.26, MAC AORs 1.09, 1.2, and 1.1, respectively; all p < 0.0001). Treatment in the Midwest, South, or West was associated with decreased odds of receiving alternatives to general anesthesia compared to the Northeast (regional anesthesia AORs 0.28, 0.38, and 0.03, all p < 0.0001; MAC 0.76, 0.13, and 0.43, respectively; all p < 0.05).

CONCLUSIONS

Use of regional anesthesia and MAC with local anesthesia for arteriovenous access creation has decreased over time with general anesthesia remaining the primary anesthetic type. Anesthetic choice, however, varies with patient characteristics and geography.

Cross-leg free flaps and cross-leg vascular cable bridge flaps for lower limb salvage: experience before and after COVID-19

Background

Previous reports have evidenced the disruptive effect of the COVID-19 in microsurgical and reconstructive departments. We report our experience with cross-leg free flaps and (CLFF) and cross-leg vascular cable bridge flaps (CLVCBF) for lower limb salvage, technical consideration to decrease morbidity, and some structural modifications to our protocols for standard of care adapted to the COVID-19.

Methods

We retrospectively included consecutive patients undergoing reconstruction with CLFFs and CLVCBFs for lower limb salvage from January 2003 to May 2022. We extracted data on baseline demographic characteristics, mechanism of trauma, and surgical outcomes.

Results

Twenty-four patients were included, 11 (45.8%) underwent reconstruction with CLFF while 13 had CLVCBFs (54.2%). Fifteen patients (62.5%) underwent lower limb reconstruction under general anesthesia while 9 (37.5%) had combined spinal-epidural anesthesia. During COVID-19 pandemic, six CLFF cases were performed under S-E (25%). The average time for pedicle transection of muscle CLFFs and muscle CLVCBFs was comparable between groups (60 days versus 62 days, p = 0.864). A significantly shorter average time was evidenced for pedicle division of fasciocutaneous flaps in the CLFF group when compared to CLVCBFs (45 days versus 59 days, p = 0.002).

Conclusions

In selected patients, CLFFs and CLVCBFs offer an optimal alternative for lower limb salvage using recipient vessels out of the zone of injury from the contralateral limb. Modification in the surgical protocols can decrease improve resource allocation in the setting of severely ill patients during COVID-19.Level of evidence: Level III, Therapeutic.

The Effects of Vasodilation Induced by Brachial Plexus Block on the Development of Postoperative Thrombosis of the Arteriovenous Access in Patients with End-Stage Renal Disease: A Retrospective Study

Although brachial plexus block (BPB)-induced vasodilation reduces the incidence of arteriovenous access (AC) thrombosis, BPB cannot completely prevent its development. Therefore, we retrospectively investigated the factors affecting BPB-induced vasodilation and their effects on AC thrombosis development. Ninety-five patients undergoing AC surgery under BPB were analyzed. Vessel diameters were measured before and 20 min after BPB. The surgery abandoned before the BPB placement was performed when the BPB-induced increases in vessel diameters met its indications. Complete occlusive access thrombosis (COAT) was defined as loss of pulse, thrill, or bruit. Fourteen patients (14.7%) developed COAT. The outflow vein was more dilated by BPB than the inflow artery (0.6 versus 0.1 mm in median, p < 0.001). The original surgery plan was changed for seven patients (7.4%). Diabetes mellitus (DM) and ischemic heart disease (IHD) decreased the extent of increases in the inflow artery by -0.183 mm (95% confidence interval [CI] [-0.301, -0.065], p = 0.003) and outflow vein diameters by -0.402 mm (95% CI [-0.781, -0.024], p = 0.038), respectively. However, DM, IHD, and changes in the vessel diameters had insignificant effects on the development of COAT. In conclusion, although DM and IHD attenuate the vasodilating effects of BPB, they do not contribute to the development of COAT.

A preliminary animal study on the prediction of nerve block success using ultrasonographic parameters

This study aimed to evaluate the diagnostic value of ultrasonographic parameters as an indicator for predicting regional nerve block success. Ultrasound-guided sciatic nerve block was performed in seven dogs using either 2% mepivacaine (nerve-block group) or saline (sham-block group). The cross-sectional area (CSA), nerve blood flow (NBF), and shear wave velocity (SWV) of the sciatic nerve (SWV_N), SWV of the biceps femoris muscle (SWV_M), and their ratio (SWV_NMR) were measured at 0, 30, 60, and 90 min after the nerve block as well as the change rate of each parameter from the baseline. A receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic value of each parameter in the prediction of nerve block success. No significant changes were observed in the CSA or NBF in association with the nerve block. The SWV_N and SWV_NMR in the nerve-block group were significantly higher than those in the sham-block group at 90 min and at 30, 60, and 90 min, respectively (p < 0.05). The change rates of SWV_N and SWV_NMR in the nerve-block group were significantly higher than those in the sham-block group at all time points (p < 0.05). The ROC curve analysis showed that SWV_N had a moderate diagnostic accuracy (area under the curve [AUC], 0.779), whereas SWV_NMR and change rates of SWV_N and SWV_NMR had a high diagnostic accuracy (AUC, 0.947, 0.998, and 1.000, respectively). Ultrasonographic evaluation of the SWV_N and SWV_NMR could be used as indicators for predicting nerve block success.

Ultrasound-guided cradle-like infiltrative anesthesia for percutaneous transluminal angioplasty of stenotic autogenous arteriovenous hemodialysis access

BACKGROUND

Percutaneous transluminal angioplasty (PTA) is an effective treatment for autogenous arteriovenous hemodialysis access (AAVA) stenosis; however, it causes pain in most cases. Therefore, safe and effective anesthesia for PTA is required.

METHODS

We introduced a method of ultrasound-guided cradle-like infiltration anesthesia (UCIA) to administer analgesia during PTA. Using ultrasound guidance, 1% lidocaine was injected into the bilateral and inferior perivascular spaces of the stenosis to form a cradle-like region. In this study, 100 consecutive patients were divided into two groups, and the analgesic effect of UCIA was evaluated using a numerical rating scale (NRS) with non-ultrasound-guided infiltration anesthesia (NUIA) as a control. Meanwhile, we compared the effect of PTA between the two groups with the postoperative internal diameter (ID) of the stenosis.

RESULTS

The NRS score was 4.6±1.9 and 2.0±1.6 (p<0.001) in UCIA group and NUIA group, respectively. The postoperative ID of stenosis was 3.9±0.6 mm and 4.1±0.7 mm (p=0.113); the postoperative AAVA flow volume was 627±176 mL/min and 644±145 mL/min (p=0.600).

CONCLUSION

This study preliminarily showed that UCIA is effective and safe for the analgesia of AAVA PTA.

Regional Anesthesia for Symptomatic Treatment of Stingray Envenomation

Stingray envenomation is common in coastal regions around the world and may result in intense pain that can be challenging to manage. Described therapies involve hot water immersion and potentially other options such as opioid and nonopioid analgesics, removal of the foreign body, wound debridement, antibiotics for secondary infection, and tetanus toxoid. However, for some patients, this may not be enough. Peripheral nerve blockade is a frequently used perioperative analgesic technique, but it has rarely been described in the management of stingray envenomation. Here, we report a case of stingray envenomation in an otherwise healthy 36-y-old male with pain refractory to traditional therapies. After admission for pain control, the patient received an ultrasound-guided sciatic popliteal nerve block. Upon completion of the peripheral nerve block, the patient reported rapid and complete resolution of the intense pain, which did not return thereafter.

Maturation and Patency Rates in Basilic Transposition Arteriovenous Fistula Under Regional Versus General Anesthesia: A Single-Center, Retrospective, Observational Study

Background Basilic transposition arteriovenous fistula (BT AVF) is a viable option for dialysis-dependent patients, which can be performed under either general or regional anesthesia. Regional anesthesia is reported to cause vascular dilatation during the perioperative period, leading to improved fistula success. Regional anesthesia is also considered safe as compared to general anesthesia in terms of hemodynamic stability. Limited and conflicting data are available comparing regional versus general anesthesia in terms of fistula maturation and patency. We aimed to compare the maturation, one-year patency rates, and complication rates in patients undergoing single-stage BT AVF in regional versus general anesthesia. Methods This retrospective observational study was conducted on patients undergoing single-stage BT AVF from January 2016 to December 2019. Patients were divided into regional (RA) vs. general anesthesia (GA) groups and compared in terms of maturation, one-year patency, and perioperative complication rates. Results Out of 152 patients, 110 (72.37%) were in GA while 42 (27.63%) were in the RA group. Elderly, female, diabetic, ischemic heart disease, and American Society of Anesthesiologists (ASA) class IV patients were more in the RA group. Other comorbid and vascular access-related factors were comparable between the groups. A trend toward higher maturation rates (97.6% vs. 92.1%) and one-year patency rates (62.5% vs. 56.6%) was observed in the RA vs. GA group, however, the difference did not attain statistical significance, p=0.359 and p=0.327, respectively. The rate of access abandonment was higher in the GA group (43.4% vs. 37.5%). The most prevalent cause of abandonment was death in the RA group while it was access failure in the GA group. Overall complication rates were comparable between both groups (20.2 % vs. 17.5%, p=0.816). Conclusion Regional anesthesia is a useful technique with potentially improved maturation and patency rates. Nevertheless, an assumed benefit of regional anesthesia in terms of anesthesia-related complications was not observed.

Anatomic suitability for commercially available percutaneous arteriovenous fistula creation systems

OBJECTIVE

The Food and Drug Administration recently approved two percutaneous arteriovenous fistula creation systems: the Ellipsys vascular access (EL) system and WavelinQ EndoAVF (WQ) system. Although the initial clinical trials of each system have demonstrated a high success rate, little detail on anatomic suitability was provided. We sought to determine the real-world applicability of the EL and WQ systems by studying them in a single representative cohort.

METHODS

All patients receiving a first-time arteriovenous access consultation at a single Veterans Affairs institution underwent extensive vein mapping of the bilateral upper extremities. Anatomic suitability was assessed in accordance with the manufacturer's instructions for use (IFU), and clinical usability was determined using additional published anatomic guidelines. The suitability for radiocephalic fistula (RCF) creation was also assessed. To estimate how often these systems would be used in practice, a clinical algorithm was created, with a preference for RCF creation, followed by percutaneous arteriovenous fistula (pAVF) creation, surgical fistula creation at the elbow, and, finally, graft placement.

RESULTS

During the study period, 116 upper extremities were measured in 58 male patients. Per the IFU, the rate of extremity suitability was 93% and 52% for the WQ and EL systems, respectively (P < .0001). In the same population, 32% of the extremities had acceptable anatomy for RCF creation. The overall clinical usability of these systems using more recent published guidelines was 55% for the WQ system and 44% for the EL system (P = .09). The usability of both pAVF systems was most limited by the size of the deep perforating cubital vein. The proximity of the antecubital perforator vein and proximal radial artery additionally limited EL usability. Based on the clinical algorithm, initial access creation would have been RCF creation for 31% of the cohort, followed by the WQ (32%), the EL (23%), surgical fistula creation at the elbow (18%), and graft placement (17%).

CONCLUSIONS

Anatomic suitability was greater for WQ than for EL when considering only the IFU. Once the full requirements for pAVF creation were considered, we found no significant differences in usability between the two systems. Anatomic analysis showed that pAVF creation can constitute a substantial part of a hemodialysis access practice.

Quality of postoperative recovery after upper-arm vascular surgery for hemodialysis in patients with end-stage renal disease: A prospective comparison of cervical epidural anesthesia vs general anesthesia

Cervical epidural anesthesia (CEA) is generally not used during upper-arm vascular surgery for hemodialysis in end-stage renal disease (ESRD) patients, despite its advantages. The Quality of Recovery-40 questionnaire (QOR-40) has been validated as a tool for assessing the degree of recovery after surgery. We hypothesized that CEA could provide a better outcome on the QOR-40 than general anesthesia after upper-arm vascular surgery for hemodialysis in ESRD patients.We divided anesthetic methods into general anesthesia and CEA. The QOR-40 was administered to 70 patients on the night before surgery and at 24 hours after surgery. Additional data, including consumption of opioid analgesics, occurrence of postoperative nausea and vomiting, and scores on a numeric rating scale (NRS) were collected.The total QOR-40 scores of the two groups differed significantly (P = .024) on postoperative day 1. Opioid consumption (P = .005) and occurrence of postoperative nausea (P = .019) in the post-anesthesia care unit (PACU) were significantly lower in the CEA group, whose NRS scores were significantly lower in the PACU (P < .001) and at postoperative day 1 (P = .016).Assessment of postoperative quality of recovery after upper-arm vascular surgery in ESRD patients showed that the CEA group had significantly better total QOR-40 and NRS scores. CEA could be used as an alternative anesthetic technique for upper-arm vascular surgery for hemodialysis in ESRD patients to improve the quality of recovery.

Blood flow index as an indicator of successful sciatic nerve block: a prospective observational study using laser speckle contrast imaging

BACKGROUND

Laser speckle contrast imaging allows real-time, non-invasive, quantitative measurements of regional blood flow. The objectives of this prospective observational study were to use laser speckle contrast imaging to evaluate blood flow changes after sciatic nerve block, and to determine whether this novel optical technique can evaluate block success.

METHODS

This observational study included 63 adult patients undergoing elective lower limb surgery with sciatic nerve block. Blood flow images and blood flow index (BFI) values of toes were recorded using laser speckle contrast imaging 5 min before nerve block and at 5 min intervals until 30 min after sciatic block. The sensitivity, specificity, and cut-off value of laser speckle contrast imaging for predicting successful sciatic block were determined by receiver operator characteristic (ROC) curve analysis.

RESULTS

The BFI values of toes were significantly increased at each time point after successful sciatic block, compared with the baseline value obtained 5 min before nerve block; in failed sciatic block, there were no significant differences. For successful sciatic block, the highest increase of BFI value was at the big toe. BFI increase of the big toe at 10 min after sciatic block has great potential as an indicator of block success. The area under the ROC curve was 0.954 at a cut-off value of 8.48 perfusion units (PU) with a sensitivity of 89% and a specificity of 100%.

CONCLUSIONS

Laser speckle contrast imaging might be an early, objective, quantitative, and reliable indicator of successful sciatic block. BFI increase of the big toe not reaching 8.48 PU within 10 min after sciatic block indicates block failure.

CLINICAL TRIAL REGISTRATION

NCT03169517.

Adding a PECS II block for proximal arm arteriovenous access - a randomised study

BACKGROUND

Brachial plexus block is often utilised for proximal arm arteriovenous access creation. However, the medial upper arm and axilla are often inadequately anaesthetised, requiring repeated, intraoperative local anaesthetic supplementation, or conversion into general anaesthesia. We hypothesised that the addition of a PECS II block would improve anaesthesia and analgesia for proximal arm arteriovenous access surgery.

METHODS

In this prospective, double-blinded, randomised proof-of-concept study, 36 consenting adults with end-stage renal disease aged between 21 and 90 years received either a combined supraclavicular and PECS II block (Group PECS, n = 18), or combined supraclavicular and sham block (Group SCB, n = 18) for proximal arm arteriovenous access surgery. Primary outcome was whether patients required intraoperative local anaesthetic supplementation by the surgeon.

RESULTS

In Group PECS, 33.3% (6/18) needed local anaesthetic supplementation vs. 100% (18/18) in Group SCB. Group SCB had three times (RR 3.0, 95% CI 1.6-5.8; P < 0.001) the risk of requiring intraoperative local anaesthetic supplementation. Group PECS required lower volume of supplemental local anaesthetic compared to Group SCB (0.0 ml, IQR 0.0-6.3 ml vs. 15.0 ml, IQR 7.4-17.8 ml; P < 0.001). Group SCB had twice [RR 2.2, 95% CI 1.1-4.4; (P = 0.019)] the risk of needing additional sedation or analgesia. There were no significant differences between the groups with respect to postoperative visual analogue scale pain scores, time to first rescue analgesia or patient satisfaction.

CONCLUSION

The results suggest that adding a PECS II block to a supraclavicular block improves regional anaesthesia for patients with end-stage renal disease undergoing proximal arm arteriovenous access surgery.

Post-General Anesthesia Ultrasound-Guided Venous Mapping Increases Autogenous Access Placement Rates

BACKGROUND

This study investigates the impact of introducing a post-general anesthesia ultrasound (PAUS) mapping on the type of vascular access chosen for hemodialysis in patients without previous accesses.

METHODS

Two hundred three of 297 consecutive patients met inclusion criteria and were reviewed. Within-subjects analysis was performed on patients with both an outpatient ultrasound-guided vein mapping and a PAUS using sign tests and Wilcoxon signed rank tests. Furthermore, a between-subjects analysis added patients with only the outpatient vein mapping; demographic and comorbidity data were analyzed using t-tests and chi-squared tests. An ordinal logit regression was run for the type of access placed, while a bivariate logit regression was used to compare rates of autogenous access maturation.

RESULTS

One hundred sixty-five (81%) patients received both a standard outpatient vein mapping and a PAUS. At the outpatient vein mapping, 130 (79%) patients had suitable veins for an autogenous access, whereas 35 (21%) patients did not have suitable veins for an autogenous access and were planned for a prosthetic access. During PAUS, all 165 (100%) patients were found to have suitable veins for autogenous access formation (P < 0.001). When comparing specific autogenous access configurations, Wilcoxon signed rank testing showed significantly more preferable access configurations in the PAUS group than the outpatient mapping (P < 0.001); outpatient mapping resulted in 81 (47%) radiocephalic accesses, 10 (6%) radiobasilic accesses, 20 (12%) brachiocephalic accesses, 19 (12%) brachiobasilic accesses, and 35 (21%) prosthetic accesses planned, in contrast to 149 (90%) radiocephalic accesses, 3 (2%) radiobasilic accesses, 10 (6%) brachiocephalic accesses, 3 (2%) brachiobasilic accesses, and 0 prosthetic accesses when the same patients were analyzed using PAUS. With the analysis expanded to include the 38 (19%) patients with only the outpatient vein mapping (without-PAUS), the Wilcoxon-Mann-Whitney test showed no significant differences between the groups in terms of outpatient vein mapping plans (P = 0.10); however, when comparing the PAUS plans to the outpatient vein mapping plans, there was again a significantly increased proportion of preferred access types in the PAUS group compared with the outpatient group (P < 0.001). In the ordinal logit multivariate analysis, the only significant variable was the postanesthesia ultrasound, which positively correlated with more favorable access configurations (coefficient = 2.61, P < 0.001). The bivariate logit regression for autogenous access maturation rates found no significant difference between the without-PAUS group and the PAUS group (P = 0.13).

CONCLUSIONS

Introducing a postanesthesia ultrasound mapping to guide vein-finding significantly increases the quality and quantity of suitable veins found, subsequently leading to increased proportions preferred access placement (autogenous versus prosthetic and forearm versus upper extremity).

Dose-response studies of Ropivacaine in blood flow of upper extremity after supraclavicular block: a double-blind randomized controlled study

Background

The sympathetic block of upper limb leading to increased blood flow has important clinical implication in microvascular surgery. However, little is known regarding the relationship between concentration of local anesthetic and blood flow of upper limb. The aim of this dose–response study was to determine the ED₅₀ and ED₉₅ of ropivacaine in blood flow after supraclavicular block (SB).

Methods

Patients undergoing upper limb surgery and supraclavicular block were randomly assigned to receive 30ml ropivacaine in concentrations of 0.125%(A Group), 0.2%(B Group), 0.25%(C Group), 0.375%(D Group), 0.5%(E Group), or 0.75%(F Group) (n=13 per group). All patients received supraclavicular block (SB). Time average maximum velocity (TAMAX), cross-sectional area (CSA) of brachial artery and skin temperatures (T_s) were measured repeatedly at the same marked points, they were taken at baseline (before block, t₀) and at 30min after SB (t₁). Blood flow(BF) = TAMAX× CSA×60 sec.. Relative blood flow (ΔBF) = BF_t1/ BF_t0. Success of SB was assessed simultaneously. Supplementary anesthesia and other adverse events (AE) were recorded.

Results

Significant increase in TAMAX, CSA, BF and T_s were seen in all concentration groups at t₁ comparing with t₀ (P<0.001). There was an upward trend of TAMAX, CSA, BF with the increasing concentration of ropivacaine except T_s. There was no significant different of T_s at t₁ among different concentration group. The dose-response formula of ropivacaine on ΔBF was Y=1+3.188/(1+10^((−2.451-X) × 1.730)) and ED₅₀/ED₉₅ (95%CI) were 0.35/1.94%(0.25–0.45/0.83–4.52), and R² (coefficient of determination) =0.85. ED₅₀/ED₉₅ (95%CI) values of sensory block were 0.18/0.33% (0.15–0.21/0.27–0.51), R²=0.904.

Conclusions

The dose-response curve between SB ropivacaine and the changes of BF was determined. The ED₅₀/ED₉₅ of ropivacaine of ΔBF are 0.35/1.94% (0.25–0.45/0.83–4.52). TAMAX, CSA and BF consistently increased with ropivacaine concentration. The maximal sympathetic block needs higher concentration than that complete sensation block needs which may benefit for microvascular surgery.

Trial registration

Clinicaltrials.govNCT02139982. Retrospectively registered (Date of registration: May, 2014).

Minimally invasive basilic vein transposition in the arm or forearm for autogenous haemodialysis access: A less morbid alternative to the conventional technique

OBJECTIVE

To devise a minimally invasive, less morbid yet effective alternative technique for basilic vein transposition (BVT) in the arm/forearm and to compare perioperative outcomes with the conventional technique.

PATIENTS AND METHODS

Patients undergoing BVT in the last two years (June 2013 to June 2015) were included in the study and the results were analysed. All patients were preoperatively evaluated using colour Doppler ultrasonography performed by the operating surgeon himself. For minimally invasive BVT, two or three small 1-2 cm incisions were made to completely mobilise the basilic vein, transposed in an anterolateral arm/forearm tunnel, and then anastomosed to the brachial or radial artery in the forearm and arm, respectively. The incision in the conventional technique was along the full length of the basilic vein, with the rest of the procedure remaining the same. Complications, pain, analgesic use, maturation and primary patency rates were compared between the techniques.

RESULTS

In all, 30 patients underwent minimally invasive BVT and 34 patients underwent conventional BVT, with mean age of 52 and 55 years, respectively. The complications of wound haematoma (one vs four) and wound infection/dehiscence (two vs six) were less common in the minimally invasive BVT group compared to the conventional group. The analgesic requirement and visual analogue scale pain score was significantly less in the minimally invasive BVT group. All other variables assessed, such as maturation and primary patency rate at 1 year, were not significantly different between the groups.

CONCLUSION

Minimally invasive dissection of the basilic vein for vascular access transposition is a safe, reliable procedure with patency and functional outcomes comparable with those of conventional BVT.

Regional versus local anesthesia for arteriovenous fistula creation in end-stage renal disease: a systematic review and meta-analysis

There is a consensus in the literature that regional anesthesia (RA) improves local hemodynamic parameters in comparison to local anesthesia (LA) during arteriovenous fistula (AVF) surgical construction. However, the effects of both techniques on fistula patency and failure rates are still controversial. The aim of this meta-analysis is to synthesize evidence from published randomized trials and observational studies regarding the safety and efficacy of RA versus LA in AVF surgical construction. A computer literature search of PubMed, Scopus, Web of Science, and Cochrane Central retrieved six randomized trials (462 patients) and one retrospective study (408 patients). Pooling data using RevMan software (version 5.3) showed that RA was superior to LA in terms of primary fistula patency rate (RR = 1.22, 95% CI [1.08, 1.37], p = 0.0010); however, both types were comparable in terms of primary fistula failure rate (RR = 0.81, 95% CI [0.47, 1.40], p = 0.46). In comparison to LA, RA was associated with improved hemodynamic parameters including fistula blood flow (MD = 25.08, 95% CI [19.40, 30.76], p<0.00001), brachial artery diameter (SMD = 2.63, 95% CI [2.17, 3.08], p<0.00001), and outflow venous diameter (SMD = 0.93, 95% CI [0.30, 1.75], p = 0.004). Postoperative complications were comparable between both groups (OR = 0.23, 95% CI [0.05, 0.97], p = 0.05). In conclusion, RA was associated with higher primary patency rates of AVF and improved local blood flow in comparison to LA; however, both procedures were comparable in terms of primary failure rates and postoperative complications. Larger well-designed trials with longer follow-up periods should compare both techniques in terms of long-term patency rates and safety outcomes.

General, regional or local anesthesia for successful radial cephalic arteriovenous fistula

Autogenous fistulas and in particular radiocephalic fistulas are recommended as the first vascular access for hemodialysis. Unfortunately, the rates of early failure and non-maturation are very high. For more than a decade, brachial plexus block has been proposed as the anesthesia of choice for fistula creation due to its beneficial sympathectomy-like effect, causing vasodilation and attenuation of spasm. Until recently, there was not a single randomized clinical study supporting this proposition. Because performing regional anesthesia is time-consuming and requires expertise, many surgeons prefer local or general anesthesia for vascular access surgery. However, in August 2016 a randomized clinical trial was published showing that regional anesthesia significantly reduces early failure and improves primary and functional patency at 3 months compared to local anesthesia. The aging of the dialysis population, with their attendant morbidity and increased risk for general anesthesia, makes it clear that regional anesthesia is the recommended approach for fistula creation. The excess time required for this approach will decrease with increasing expertise along the learning curve, and will be compensated by a reduction in time that would otherwise be needed for new access construction due to failure of fistulas constructed under local anesthesia.

Perioperative management of a bilateral forearm allograft

Composite tissue allotransplantation (CTA) is a complex procedure requiring a multidisciplinary collaboration between surgeons, anesthetists, and transplantation specialists. We will describe the perioperative management of a bilateral forearm allograft performed at our facility. A 40-year-old man who lost both forearms was registered on the transplant waiting list; a suitable graft was available 11months later. Anesthesia required planning for vascular access, hemodynamic monitoring, fluid therapy management and prevention of deep vein thrombosis. Blood loss was not quantifiable, which made coagulation management challenging. Reperfusion syndrome required the use of vasopressors. Postoperatively, moderate rhabdomyolysis without acute renal failure was observed. No complications such as thrombosis, hemorrhage, or opportunistic infections occurred during the early postoperative period. A comprehensive, protocol-driven, patient care strategy is crucial for the proper conduct of the surgical procedure and graft survival.

Anesthesia for Vascular access Surgery

The type of anesthesia chosen is an integral part of the decision-making process for arteriovenous access construction. We discuss the different types of anesthesia used, with emphasis on brachial plexus block, which is potentially safer than general anesthesia in this fragile patient population with end-stage renal disease. Brachial plexus block is superior to local anesthesia and enables the use of a tourniquet to minimize potential damage to the blood vessels during anastomosis using microsurgery techniques, and does not lead to the vasospasm that may be seen with local anesthesia. Regional anesthesia has a beneficial sympathectomy-like effect that causes vasodilation with increased blood flow during surgery and in the fistula postoperatively that may prevent early thrombosis and potentially improve outcome.

Regional anesthesia for vascular surgery

Patients presenting for vascular surgery present a challenge to anesthesiologists because of their severe systemic comorbidities. Regional anesthesia has been used as a primary anesthetic technique for many vascular procedures to avoid the cardiovascular and pulmonary perturbations associated with general anesthesia. In this article the use of regional anesthesia for carotid endarterectomy, open and endovascular abdominal aortic aneurysm repair, infrainguinal arterial bypass, lower extremity amputation, and arteriovenous fistula formation is described. A focus is placed on reviewing the literature comparing anesthetic techniques, with brief descriptions of the techniques themselves.

Variability in Anesthetic Considerations for Arteriovenous Fistula Creation

Introduction

Anesthetic options for arteriovenous fistula (AVF) creation include regional anesthesia (RA), general anesthesia (GA) and local anesthetic for select cases. In addition to the benefits of avoiding GA in high-risk patients, recent studies suggest that RA may increase perioperative venous dilation and improve maturation. Our objective was to assess perioperative outcomes of AVF creation with respect to anesthetic modality and identify patient-level factors associated with variation in contemporary anesthetic selection

Methods

National Surgical Quality Improvement Project (NSQIP) data (2007-2010) were accessed to identify patients undergoing AVF creation. Univariate analysis and multivariate logistic regression were performed to assess the relationships among patient characteristics, anesthesia modality and outcome.

Results

Of 1,540 patients undergoing new upper extremity AVF creation, 52% were male and 81% were younger than 75 years. Anesthesia distribution was GA in 85.2%, local/monitored anesthetic care (MAC) in 2.9% and RA in 11.9% of cases. By multivariate analysis, independent predictors of RA were dyspnea at rest (hazard ratio [HR] 2.3, 95% confidence interval [CI] 1.1-4.9), age >75 (HR 1.6, 95% CI 1.1-2.3) and teaching hospital status as indicated by housestaff involvement (HR 3.7, 95% CI 2.5-5.5). RA was associated with higher total operative time, duration of anesthesia, length of time in operating room and duration of anesthesia start until surgery start (p<0.01). There were no differences between perioperative complications or mortality among anesthetic modalities, although all deaths occurred in the GA group.

Discussions

Despite recent reports highlighting potential benefits of RA for AVF creation, GA was surprisingly used in the vast majority of cases in the United States. The only comorbidities associated with preferential RA use were advanced age and dyspnea at rest. Practice environment may influence anesthetic selection for these cases, as a nonteaching environment was associated with GA use. The trend seen here toward higher mortality in GA and the potential perioperative benefits of RA for the access should encourage more widespread use of RA in practice for this high-risk patient population.

Respiratory arrest in patients undergoing arteriovenous graft placement with supraclavicular brachial plexus block: a case series

Supraclavicular brachial plexus block is commonly used for upper extremity surgery. Respiratory arrest in three patients with end-stage renal disease after ultrasound-guided supraclavicular brachial plexus block for creation of an arteriovenous graft over a 6-month period is presented. Patients with renal failure may represent a group at particular risk for respiratory failure following supraclavicular brachial plexus block.

Preventive Hemostasis for Hemodialysis Vascular Access Surgical Reinterventions

Surgical reinterventions for treatment of complications or ligation of haemodialysis vascular access (VA), when performed in or below the mid/lower part of the upper arm, could benefit from the use of preventive haemostasis with an inflatable tourniquet. This technique offers several advantages, such as the reduced risk of bleeding and the increased accuracy of dissection allowing for a minimally invasive approach. The use of preventive haemostasis is safe, economical and time-saving. All the secondary procedures on VA that could benefit from its use are reviewed.

Anesthetic management in upper extremity transplantation: the Pittsburgh experience

BACKGROUND

Hand/forearm/arm transplants are vascularized composite allografts, which, unlike solid organs, are composed of multiple tissues including skin, muscle, tendons, vessels, nerves, lymph nodes, bone, and bone marrow. Over the past decade, 26 upper extremity transplantations were performed in the United States. The University of Pittsburgh Medical Center has the largest single center experience with 8 hand/forearm transplantations performed in 5 recipients between January 2008 and September 2010. Anesthetic management in the emerging field of upper extremity transplants must address protocol and procedure-specific considerations related to the role of regional blocks, effects of immunosuppressive drugs during transplant surgery, fluid and hemodynamic management in the microsurgical setting, and rigorous intraoperative monitoring during these often protracted procedures.

METHODS

For the first time, we outline salient aspects of upper extremity transplant anesthesia based on our experience with 5 patients. We highlight the importance of minimizing intraoperative vasopressors and improving fluid management and blood product use.

RESULTS

Our approach reduced the incidence of perioperative bleeding requiring re-exploration or hemostasis and shortened in-hospital and intensive care unit stay. Functional, immunologic and graft survival outcomes have been highly encouraging in all patients.

CONCLUSIONS

Further experience is required for validation or standardization of specific anesthetic protocols. Meanwhile, our recommendations are intended as pertinent guidelines for centers performing these novel procedures.

Pre-Operative Regional Block Anesthesia Enhances Operative Strategy for Arteriovenous Fistula Creation

Purpose

We aim to assess the effect of regional block anesthesia on vein diameter, type of AVF placement, and fistula size and flow volume.

Methods

30 patients presenting for AV access procedures were followed prospectively. Vein diameters via venous ultrasound and planned location for AV access were documented. Supraclavicular brachial plexus block was followed by repeat ultrasound and alterations in operative plan were noted. Patients returned to clinic for duplex ultrasound assessment.

Results

Average increase from baseline vein diameter with regional block was most pronounced in the lower cephalic (34%), upper cephalic (24.2%), and basilic veins (31.3%) and less in the brachial vein (8.7%). Type of AVF was modified following regional block in 14%. The rate of native AVF placement improved from 89% to 93% with regional block. Twenty-three AVF patients were available for follow-up (mean 24 weeks). Average fistula size was 7.9 mm (CI 6.9–8.9) and all patent fistulas developed flow volume >600 mL/min. Primary patency was attained in 83%. One thrombosis occurred after a basilic artery was lacerated during dialysis access. The average fistula increased 0.33 cm from post-block diameter (SD 0.22, P<.05).

Conclusions

Vein diameter increases significantly in the basilic and cephalic veins following regional block anesthesia and may improve the rate of native fistula placement. Propensity to dilate after regional block anesthesia does not predict size of the fistula.

Improving Dialysis Access: Regional Anesthesia Improves Arteriovenous Fistula Prevalence

An autologous arteriovenous (AV) fistula is the preferred form of angioaccess for chronic hemodialysis. A prospective study was carried out to evaluate the potential of regional anesthesia to improve AV fistula prevalence. One hundred ninety-three patients underwent preoperative duplex ultrasound evaluation over a 14-month period. The qualification of each patient to receive either an autologous AV fistula or a prosthetic graft was based on specific sonographic criteria. Patients scheduled for placement of a graft received an ultrasound-directed supraclavicular brachial plexus block, which produces dense sympathetic blockade. After the regional block, those patients who met criteria for primary fistula construction on repeat ultrasound received a fistula instead of a graft. Of 62 patients scheduled to receive an AV graft, 23 or 37 per cent were recruited to receive a fistula instead. The outcome of the recruited fistulas was compared with the 121 planned fistulas. There was no statistically significant difference in primary failure rate (4.3 vs 5.8%). The recruited fistulas had a shorter average maturation time, 83 ± 48 versus 132 ± 82 days ( P = 0.023). Within the study population, functioning fistula prevalence was increased from 61.7 to 79.8 per cent. Regional anesthesia and immediate preoperative ultrasound is a useful strategy for increasing fistula prevalence.

Duplex Scanning–Derived Access Volume Flow: Novel Predictor of Success Following Endovascular Repair of Failing or Nonmaturing Arteriovenous Fistulae for Hemodialysis

The objective of this study was to evaluate the feasibility of duplex scanning–derived access volume flow (DAVQ) to predict the success or failure of arteriovenous fistulae (AVF) after interventions. Eighty-eight DAVQ measurements were available for 60 AVF in 59 patients. In 25 cases, physical examination findings or inadequate dialysis suggested failing (11) or nonmaturing (14) AVF. Outflow stenoses (1–4; mean 1.2 ± 0.8) were confirmed by contrast fistulograms in 23 cases (17 peripheral; 6 central). These 23 cases underwent successful endovascular repair (17 balloon angioplasty; 6 stents) and had pre- and postintervention DAVQ measurements within 2 weeks of the procedure. Each was measured three times in a nontortuous venous segment with laminar flow, and mean values were used for comparison. The overall mean DAVQ for 65 functioning AVF was 1,199 ± 485 mL/min, whereas it was 652 ± 438 mL/min (range 150–1,840 mL/min) for the remaining 23 failing or nonmaturing cases ( p < .0001). Postintervention, the latter values changed to 867 ± 517 mL/min (range 257–2,020 mL/min), with a p < .13. Of these, 11 were still nonfunctional after endovascular procedures and had a mean DAVQ of 404 ± 111 mL/min (range 257–652 mL/min). The remaining 12 cases had a mean DAVQ of 1,280 ± 382 mL/min (range 762–2,020 mL/min) and were functional and usable for at least 6 months of follow-up ( p < .0001). It is interesting to note that none of the AVF cases with postintervention DAVQ < 700 mL/min became functional and usable, whereas all cases with a higher DAVQ underwent successful hemodialysis treatments. This early experience suggests that DAVQ can be used to predict the success or failure of an AVF following endovascular procedures. To our knowledge, this is the first such report.

[Cardiac arrest after axillary plexic anaesthesia with ropivacaine in a chronic kidney failure dialysis patient]

The local anaesthetics are responsible for an important part of morbidity and mortality during conduction anaesthesia. We describe fatal accident plexic anaesthesia with ropivacaine in spite of a classical reanimation measure in a dialysis patient.