Anesthesia for Vascular access Surgery

Microsurgery and vasospasms: Spasms' predictive factors during harvesting

BACKGROUND

Vasospasm (VS) in microsurgery is a source of surgical complications, repeat operations, stress for the patient and the surgical team, as well as increased length of stay. Various risk factors have been identified but knowledge regarding the implicated mechanism remains limited.

HYPOTHESIS

Our objective was to determine if the harvesting conditions for microsurgical toe transfers could increase the risk of VS. Our secondary objective was to determine the correlation between VS occurrence before flap division, and the occurrence of vascular complications after completion of vascular anastomoses.

PATIENTS AND METHODS

Primary endpoints were the existence of locoregional anaesthesia of the lower limb, the Gilbert classification, the nature of the graft taken from the foot, the characteristics of the patients and smoking status. Our secondary endpoints were the presence of secondary VS or microsurgical failure. This series consists of 14 toe transfers over a 30-month period. Primary VS was defined as occurring prior to flap division, while secondary VS occurred after transfer.

RESULTS

In this series, we identified 4 cases of primary VS. The average age of the operated population was 30.6 ± 11.2 years (16-58). The patients who presented with primary VS had a mean age of 35.3 ± 16.2 years (21-58), with no statistical difference with the other group (p = 0.54). There was a statistically significant difference between the absence of locoregional anaesthesia and the occurrence of primary VS in toe transfer (p = 0.0008). Microsurgical failure occurred in 1 case. This failure was linked to the presence of a primary VS. Gilbert's classification and type of graft were not predictive of VS (p = 0.15 and p = 0.08, respectively). The occurrence of secondary VS was statistically linked to the occurrence of primary VS (p = 0.009).

DISCUSSION

The occurrence of VS remains unpredictable and the effectiveness of available treatments is debated in the literature. Faced with the failure of curative treatments, this study aimed to determine predictive factors for VS. The existence of secondary VS, when prolonged and non-responsive to conventional measures, can lead to anastomotic revision. Performing locoregional anaesthesia on the lower limb makes it possible to effectively combat the occurrence of VS. The absence of primary VS was correlated with an absence of secondary VS and an absence of microsurgical failure. In addition to controlling vasospasm, regional anaesthesia provides effective analgesia at the harvesting site.

LEVEL OF EVIDENCE

IV.

Effect of anesthetics on postoperative nausea and vomiting after peripheral vascular surgery in end-stage renal disease patients: A retrospective observational study

Background

Propofol-based total intravenous anesthesia (TIVA) is considered a prophylactic approach to decrease postoperative nausea and vomiting (PONV). Despite general anesthesia commonly being performed in end-stage renal disease (ESRD) patients, PONV in ESRD patients has not been well-described. We investigated PONV in peripheral vascular surgery under general anesthesia in ESRD patients.

Methods

To compare PONV between propofol-based TIVA and anesthesia with volatile anesthetics, we collected retrospective data from patients who underwent peripheral vascular surgery under general anesthesia from July 2018 to April 2020. We performed univariable and multivariable analyses, including factors that could be associated with PONV and those previously shown to affect PONV.

Result

A total of 1,699 peripheral vascular surgeries under general anesthesia in ESRD patients were eligible for analysis. Based on the multivariable analysis, TIVA (odds ratio [OR], 0.45; 95% confidence interval [CI], 0.35-0.60; P < 0.001) significantly decreased PONV. Female sex (OR, 1.85; 95% CI, 1.44-2.38; P < 0.001) and anesthetic duration (OR, 1.01; 95% CI, 1.00-1.01; P < 0.001) were associated with increased PONV.

Conclusion

Propofol-based TIVA is the most influential factor decreasing PONV after peripheral vascular surgery in ESRD patients. Anesthesiologists can apply propofol-based TIVA as an alternative to anesthesia with volatile anesthetics.

Expandability of Cephalic Veins after Brachial Plexus Block in Arteriovenous Fistula Formation for Hemodialysis

Background

Arteriovenous fistula (AVF) for hemodialysis is essential for patients with end-stage renal disease. However, it is difficult to maintain AVF reliably. It is vitally important to select proper blood vessels for AVF formation. In a previous study, a minimum diameter of 3 mm for the autologous vein was proposed. However, patients who did not meet the minimum vascular diameter before anesthesia, but fulfilled other criteria, showed satisfactory venous dilatation after brachial plexus block (BPB). This study investigated the extent of vein expansion by BPB and the surgical outcomes of dilated veins after BPB.

Methods

Sixty-one patients who underwent AVF formation using an autologous vein between August 2018 and December 2019 were included in the study. The clinical characteristics of the patient groups, hemodynamic parameters including the diameter of blood vessels before and after BPB, and complications were investigated. Based on the venous diameter measured by sonography before anesthesia, patients were divided into group A (26 patients) and group B (35 patients), with venous diameters <3 mm and ≥3 mm, respectively.

Results

The venous diameter expanded after anesthesia by 41% overall, by 62% in group A, and by 25% in group B. This difference between groups A and B was statistically significant (p=0.001). No other variables showed statistically significant differences.

Conclusion

Sufficient venous dilatation was observed after BPB. Therefore, if the vein is sufficiently dilated after BPB, even in patients with a pre-anesthesia venous diameter <3 mm, surgery may still be performed with an expected desirable outcome.

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.

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.

Axillary brachial plexus block duration with mepivacaine in patients with chronic renal failure. Case-control study

INTRODUCTION

Regional anaesthesia is commonly preferred for arteriovenous fistula (AVF) creation. Previous studies suggest a shorter block duration in patients with chronic renal failure, maybe because of the changes in regional blood flow. The aim of our study was to evaluate the duration of the axillary block with 1.5% mepivacaine in patients with chronic renal failure scheduled for AVF compared with healthy controls.

METHODS

Patients scheduled for AVF creation for the first time (GIRC) were included. They were compared with patients without renal failure (GC), with similar anthropometric characteristics. Ultrasound-guided axillary blocks with 20mL of 1.5% mepivacaine were performed on all patients. We evaluated onset time, humeral artery diameter and blood flow before and after the block, as well as the block duration.

RESULTS

Twenty-three patients (GIRC: 12 and GC: 11) were included. No differences between groups were observed in block duration (GIRC: 227±43min vs GC: 229±27min; P=.781), or in onset time (GIRC: 13±5min vs GC: 12.2±3min; P=.477). The humeral blood flow before and after block was significantly lower in the GIRC (pre-block: GIRC: 52±21ml/min GC: 100±62ml/min; P=.034 and p ost block: GIRC: 130±57ml/min and GC: 274±182ml/min; P=.010). There was no significant correlation between the duration of the block and the preblock humeral blood flow (Spearman Rho: 0.106; P=.657) or the postblock humeral blood flow (Spearman Rho: 0.267; P=.254).

CONCLUSION

The duration of the axillary block with 1.5% mepivacaine in patients with chronic renal failure was similar to that of the control patients. The duration of axillary brachial plexus block seems not to be related to changes in regional blood flow.

Upper Limb Grafts for Hemodialysis Access

Arteriovenous (AV) grafts are required for hemodialysis access when options for native fistulas have been fully exhausted, where they continue to play an important role in hemodialysis patients, offering a better alternative to central vein catheters. When planning autogenous accesses using Doppler ultrasound, adequate arterial inflow and venous outflow must be consciously preserved for future access creation with grafts. Efforts to improve graft patency include changing graft configuration, graft biology and hemodynamics. Industry offers early cannulation grafts to reduce central catheter use and a bioengineered graft is undergoing clinical studies. Although the outcome of AV grafts is inferior to fistulas, grafts can provide long-term hemodialysis access that is a better alternative to central venous catheters. AV grafts have significant drawbacks, mainly poor patency, infection and cost but also have some advantages: early maturation, ease of creation and needling and widespread availability. The outcome of AV graft surgery is variable from center to center. The primary patency rate for AV grafts is 58% at 6 months and the secondary patency rate is 76% at 6 months and 55% at 18 months. There are centers of excellence that report a 1 year secondary patency rate of up to 91%. In this review of the use of AV grafts for hemodialysis access in the upper extremities, technical issues involved in planning the access and performing the surgery in its different configurations are discussed and the role of surveillance and maintenance with their attendant surgical and radiological interventions is described.