Comparing outcomes after peripheral nerve block versus general anesthesia for lower extremity amputation: a nationwide exploratory retrospective cohort study in Japan

Ultrasound-Guided peripheral nerve blocks for major amputation in critically ill patients with peripheral artery disease

OBJECTIVE

The aim of this study was to assess the safety and efficacy of major amputation under ultrasound-guided peripheral nerve blocks in critical peripheral artery disease (PAD) patients.

METHODS

We reviewed the medical records of consecutive patients who underwent major amputation at our center between December 2012 and December 2020. The patients' baseline demographics and comorbidities were collected. The primary outcomes were 30-day and 12-month mortality. The secondary outcomes were intraoperative events, complications and intensive care unit (ICU) admission.

RESULTS

Fifteen patients classified as American Society of Anesthesiologist (ASA) III and 13 ASA IV (mean age: 76.07 ± 11.78 years) were included in the study. These patients were critically ill and had many comorbidities, such as coronary artery disease. All amputations were successfully performed under ultrasound-guided PNB without conversion to GA, but intravenous analgesia was given in 7 patients during the operation. The majority of the patients had stable hemodynamics except for 2 patients who had hypoxia, so none of the patients were transferred to the ICU postoperatively. None of the patients suffered from acute cardio-cerebral events. However, 5 patients had wound infections, and 4 of 5 patients had to receive reamputation. None of the patients died within 48 h after amputation. However, the 30-day mortality was 3.57%, and the 12-month mortality was up to 35.71%.

CONCLUSION

This study demonstrates that major amputation could be safely and effectively performed under ultrasound-guided peripheral nerve blocks for critically ill patients, and ultrasound-guided peripheral nerve blocks could be an alternative for patients at high risk of general anesthesia or spinal anesthesia.

Focused ultrasound-induced inhibition of peripheral nerve fibers in an animal model of acute pain

BACKGROUND

Moderate-to-severe acute pain is prevalent in many healthcare settings and associated with adverse outcomes. Peripheral nerve blockade using traditional needle-based and local anesthetic-based techniques improves pain outcomes for some patient populations but has shortcomings limiting use. These limitations include its invasiveness, potential for local anesthetic systemic toxicity, risk of infection with an indwelling catheter, and relatively short duration of blockade compared with the period of pain after major injuries. Focused ultrasound is capable of inhibiting the peripheral nervous system and has potential as a pain management tool. However, investigations of its effect on peripheral nerve nociceptive fibers in animal models of acute pain are lacking. In an in vivo acute pain model, we investigated focused ultrasound's effects on behavior and peripheral nerve structure.

METHODS

Focused ultrasound was applied directly to the sciatic nerve of rats just prior to a hindpaw incision; three control groups (focused ultrasound sham only, hindpaw incision only, focused ultrasound sham+hindpaw incision) were also included. For all four groups (intervention and controls), behavioral testing (thermal and mechanical hyperalgesia, hindpaw extension and flexion) took place for 4 weeks. Structural changes to peripheral nerves of non-focused ultrasound controls and after focused ultrasound application were assessed on days 0 and 14 using light microscopy and transmission electron microscopy.

RESULTS

Compared with controls, after focused ultrasound application, animals had (1) increased mechanical nociceptive thresholds for 2 weeks; (2) sustained increase in thermal nociceptive thresholds for ≥4 weeks; (3) a decrease in hindpaw motor response for 0.5 weeks; and (4) a decrease in hindpaw plantar sensation for 2 weeks. At 14 days after focused ultrasound application, alterations to myelin sheaths and nerve fiber ultrastructure were observed both by light and electron microscopy.

DISCUSSION

Focused ultrasound, using a distinct parameter set, reversibly inhibits A-delta peripheral nerve nociceptive, motor, and non-nociceptive sensory fiber-mediated behaviors, has a prolonged effect on C nociceptive fiber-mediated behavior, and alters nerve structure. Focused ultrasound may have potential as a peripheral nerve blockade technique for acute pain management. However, further investigation is required to determine C fiber inhibition duration and the significance of nerve structural changes.

A Systematic Review and Meta-analysis of General versus Regional Anesthesia for Lower Extremity Amputation

OBJECTIVE

Postoperative morbidity in patients undergoing lower extremity amputation (LEA) has remained high. Studies investigating the influence of the anesthetic modality on the postoperative outcomes have yielded conflicting results. The aim of our study was to assess the effects of regional anesthesia vs general anesthesia on postoperative complications for patients undergoing LEA.

METHODS

We systematically searched PubMed, Embase, MEDLINE, Web of Science, and Google Scholar from 1990 to 2022 for studies investigating the effect of the anesthetic modality on the postoperative outcomes after LEA. Regional anesthesia (RA) included neuraxial anesthesia and peripheral nerve blocks. The outcomes included 30-day mortality, respiratory failure (unplanned postoperative intubation, failure to wean, mechanical ventilation >24 hours), surgical site infection, cardiac complications, urinary tract infection, renal failure, sepsis, venous thrombosis, pneumonia, and myocardial infarction.

RESULTS

Of the 25 studies identified, we included 10 retrospective observational studies with 81,736 patients, of whom 69,754 (85.3%) had received general anesthesia (GA) and 11,980 (14.7%) had received RA. In the GA group, 50,468 patients were men (63.8%), and in the RA group, 7813 patients were men (62.3%). The results of the meta-analyses revealed that GA was associated with a higher rate of respiratory failure (odds ratio, 1.38; 95% confidence interval, 1.06-1.80; P = .02) and sepsis (odds ratio, 1.21; 95% confidence interval, 1.11-1.33; P < .0001) compared with RA. No differences were found in postoperative 30-day mortality, surgical site infection, cardiac complications, urinary tract infection, renal failure, venous thrombosis, pneumonia, and myocardial infarction between the GA and RA groups.

CONCLUSIONS

The results of our meta-analysis have shown that GA could be associated with a higher rate of respiratory failure and sepsis compared with RA for LEA.

Minimizing Post-Intensive Care Syndrome to Improve Outcomes for Intensive Care Unit Survivors

TOPIC

Post-intensive care syndrome is a collection of symptoms that more than half of patients who survive a critical illness, and their family caregivers, experience after the illness. Those symptoms include weakness/ fatigue, sleep disturbances/insomnia, cognitive dysfunction, posttraumatic stress disorder, other mental health conditions, and a lack of effective coping strategies.

CLINICAL RELEVANCE

To minimize the risk of a patient developing post-intensive care syndrome, intensive care unit nurses must adopt practices that reduce the severity of disability and optimize patient outcomes. They must also advocate for patients who need additional expert care.

PURPOSE

To describe interventions that critical care nurses can implement to minimize a patient's risk for post-intensive care syndrome.

CONTENT COVERED

This article describes patients who have a high risk of developing post-intensive care syndrome and interventions that are within nurses' purview.

Comparing the effects of peripheral nerve block and general anesthesia with general anesthesia alone on postoperative delirium and complications in elderly patients: a retrospective cohort study using a nationwide database

INTRODUCTION

The difference between the effects of peripheral nerve block (PNB) with general anesthesia (GA) and GA alone on the patients' postoperative clinical outcomes remains unknown. We assessed whether there is a difference in postoperative delirium and composite morbidity between patients receiving GA with PNB and GA alone using a national clinical database in Japan.

METHODS

We compared the outcomes of patients receiving GA with PNB and GA alone from April 2016 to October 2019. The primary outcome was postoperative delirium, defined as a status requiring newly prescribed antipsychotic drugs or that given the code of a reimbursable disease after the surgery date. The secondary outcome was morbidity incidence as the occurrence of at least one of any of the following life-threatening complications. We conducted propensity score-matched analyses using covariates for patients who underwent any surgical procedure. We used instrumental variables and restricted the definition of postoperative delirium and subgroup for sensitivity analyses.

RESULTS

Of 653,759 patients, 90,358 received GA-PNB and 563,401 received only GA. After 1:4 propensity score matching, 89,754 patients were included in the GA-PNB and 359,015 in the GA. The adjusted ORs for postoperative delirium and composite morbidity were 0.96 (95% CIs 0.94 to 0.99; p<0.01), 0.80 (95% CIs 0.76 to 0.83; p<0.001), respectively, for the GA-PNB concerning the GA. For sensitivity analyses, findings were also consistent with instrumental variables and subgroup analyses.

DISCUSSION

This retrospective, nationwide cohort study demonstrated that GA-PNB was associated with a small reduction in the likelihood of postoperative delirium and a moderate reduction in the likelihood of composite morbidity.

The Effect of General Anesthesia vs. Regional Anesthesia on Postoperative Delirium-A Systematic Review and Meta-Analysis

Background

Postoperative delirium (POD) commonly occurs in patients following major surgeries and is associated with adverse prognosis. The modes of anesthesia may be associated with POD occurrence. General anesthesia (GA) causes loss of consciousness in the patient by altering the levels of some neurotransmitters as well as signaling pathways. We conducted this meta-analysis to investigate the effect of GA vs. regional anesthesia (RA) on POD incidence in surgical patients.

Methods

The databases of Pubmed, Embase, and Cochrane Library were searched till October 22, 2021. The eligible criteria were participants aged 18 years or older, patients undergoing surgery under GA and RA, and articles reporting the effect of GA vs. RA on POD incidence. RevMan 5.3 was used to perform statistical analyses.

Results

A total of 21 relevant trials with a total of 1,702,151 patients were included. The pooled result using random-effects model with OR demonstrated significant difference in POD incidence between patients with GA and RA (OR = 1.15, 95% CI: [1.02, 1.31], I² = 83%, p for effect = 0.02). We did not obtain the consistent pooled result after sensitivity analysis (OR = 0.95, 95% CI: [0.83, 1.08], I² =13%, p for effect = 0.44) and excluded the articles without the information on preoperative cognitive or neuropsychological assessment (OR = 1.12, 95% CI: [1.00, 1.25], I² =80%, p for effect = 0.05), respectively.

Conclusion

This meta-analysis could not identify that GA was significantly associated with POD occurrence in surgical patients compared with RA.

Chan D, Y. Liu C. Effects of regional anaesthesia on mortality in patients undergoing lower extremity amputation: A retrospective pooled analysis

Background and Aims:

Lower extremity amputation (LEA) is a commonly performed surgery and is associated with significant mortality and morbidity. This review compares the impact of anaesthetic technique on 30-day mortality and other perioperative outcomes in patients undergoing LEA.

Methods:

A systematic search of databases including PubMed, Embase, Scopus and Cochrane Central Register of Controlled Trials, from January 2010 to March 2021, was performed. Studies were eligible if they compared 30-day mortality following either general anaesthesia (GA) or regional anaesthesia (RA), in adult patients undergoing LEA.

Results:

Ten retrospective observational studies were identified. Four of these studies utilised a propensity-score matching technique. Based on these four studies, RA when compared to GA, is not associated with a reduction in the 30-day mortality (Odds ratio 0.83, 95% confidence interval (CI): 0.65, 1.05, I² 20%, P = 0.12). Also there is a very low level of evidence that RA may result in a decrease in the hospital length-of-stay and intensive care unit admissions of patients undergoing LEA.

Conclusion:

RA does not decrease the 30-day postoperative mortality in patients undergoing LEA when compared to GA.

Regional anaesthesia in the elderly patient a current perspective

PURPOSE OF REVIEW

The world's population is ageing. Although regional anaesthesia is well established, it seems there is limited evidence to support its use over general anaesthesia in the elderly. This review aims to examine recent publications of regional anaesthesia in relation to this specific patient subgroup.

RECENT FINDINGS

There is a paucity of evidence specifically relating to regional anaesthesia in the elderly patient. Studies tend to be small, retrospective and can combine assessment of multiple surgical and anaesthetic techniques in single studies. Surgical stimulus and the associated stress response are linked with an increased risk of morbidity in elderly patients. Regional anaesthesia is associated with reduced morbidity, improved pain scores, improved patient satisfaction and reduced resource allocation. Regional anaesthesia can potentially offset some of the surgical stress response and should be considered as part of a multimodal and, where possible, the primary approach to anaesthesia and analgesia in the elderly patient.

SUMMARY

Undoubtedly, peripheral nerve blocks improve analgesia and reduce opioid consumption and their associated side effects. This is beneficial in the perioperative care of elderly patients who may have less physiologic reserve to withstand these side effects. Future large prospective trials are required to evaluate the duration of action and safety profile of local anaesthetic agents and adjunct agents in the older patient.