Selective sensory spinal anaesthesia with hypobaric lidocaine for anorectal surgery

Spinal Anaesthesia Using Hypobaric Drugs: A Review of Current Evidence

Spinal anesthesia is one of the most widely used techniques in modern anesthesia practice. It involves the injection of local anesthetic drugs into the cerebrospinal fluid (CSF) within the subarachnoid space. The choice of drug, its concentration, and baricity play a crucial role in determining the characteristics of the spinal block and has evolved over the years with continuous advancements in drug formulations and administration methods. Spinal anesthesia with hypobaric drugs represents a valuable technique in the armamentarium of anesthesiologists, offering distinct advantages in terms of targeted action, reduced systemic toxicity, and enhanced hemodynamic stability. This review aims to scan the characteristics of hypobaric drugs, factors influencing their spread within the spinal canal, challenges associated with their use, clinical applications in various surgical scenarios, and potential implications for patient outcomes and healthcare practice. PubMed and Google Scholar databases were searched for relevant articles and a total of 23 relevant articles were selected for the review based on inclusion and exclusion criteria. Hypobaric drugs have many advantages in high-risk morbidly ill patients for some select surgical procedures and daycare surgeries. The concentration and volume of hypobaric drugs need to be selected according to the extensiveness of the surgery and the desired block can be achieved by giving spinal injection in specific positions. The dynamic field of anesthesiology encompasses the integration of emerging technologies and evidence-based practices, which will contribute to further refining the safety and efficacy of spinal anesthesia with hypobaric drugs.

Impact of Anesthetic Choice on Time to Discharge for Same-Day Discharge Joints

INTRODUCTION

As total joint arthroplasty programs continue to move towards same-day discharge (SDD), time to discharge is an increasingly important performance indicator. The primary objective of this study was to determine the impact of the choice of anesthetic on the time to discharge after SDD primary hip and knee arthroplasty.

METHODS

A retrospective chart review was conducted within our SDD arthroplasty program, with 261 patients identified for analysis. Baseline characteristics, length of surgery, anesthetic drug, dose, and perioperative complications were extracted and recorded. The time from the patient leaving the operating room (OR) to physiotherapy (PT) assessment, and from OR to discharge were recorded. These were referred to as ambulation time and discharge time respectively.

RESULTS

The ambulation time was significantly reduced when hypobaric lidocaine was used in a spinal block compared to isobaric or hyperbaric bupivacaine-135 minutes (range, 39 to 286), 305 minutes (range, 46 to 591), 227 minutes (range, 77 to 387) respectively-p<0.0001). Similarly, the discharge time was also significantly lower with hypobaric lidocaine compared to isobaric bupivacaine, hyperbaric bupivacaine, and general anesthesia-276 minutes (range, 179 to 461), 426 minutes (range, 267 to 623), 375 minutes (range, 221 to 511), 371 minutes (range, 217 to 570) respectively-(p<0.0001). No cases of transient neurologic symptoms were reported.

CONCLUSIONS

Patients receiving a hypobaric lidocaine spinal block experienced significantly reduced ambulation time and time to discharge compared to other anesthetics. Surgical teams should feel confident in using hypobaric lidocaine during spinal anesthesia as it is quick and efficacious.

The Density of Different Local Anesthetic Solutions, Opioid Adjuvants and Their Clinically Used Combinations: An Experimental Study

Various opioids are added to local anesthetic solutions for spinal anesthesia. This may change the final density of the local anestetic (LA) mixture. This effect regarding current concepts in spinal anesthesia needs to be re-evaluated. In order to re-evaluate such effects, hyperbaric and isobaric local anesthetic (LA) solutions were mixed with opioid adjuvants (A) using the equipment available in the operating room. Ten density measurements for each composition (LA-A) were performed. The density change of 0.0006 g/mL was regarded as significant. Measured densities were also compared with theoretical values calculated using Hare's. As a result, the addition of an opioid adjuvant caused a significant reduction in the final density of the LA-A solution. In hyperbaric LA mixtures, it did not change the baricity from hyperbaric to isobaric. However, the addition of highly hypobaric fentanyl 0.99360 g/mL (SD ± 0.00004) changes all isobaric LA solutions baricity to hypobaric. The comparison of measured and theoretical densities revealed significant differences (p > 0.05). However, the absolute reduction reached 0.0006 g/mL in only two LA-A compositions. We conclude that the addition of fentanyl to isobaric LA results in a hypobaric solution that may affect the distribution of the block. The inadequacy of LA-A in a clinical setting is unlikely to influence block characteristics.

Transient neurological symptoms (TNS) following spinal anaesthesia with lidocaine versus other local anaesthetics in adult surgical patients: a network meta-analysis

BACKGROUND

Spinal anaesthesia has been implicated as one of the possible causes of neurological complications following surgical procedures. This painful condition, occurring during the immediate postoperative period, is termed transient neurological symptoms (TNS) and is typically observed after the use of spinal lidocaine. Alternatives to lidocaine that can provide high-quality anaesthesia without TNS development are needed. This review was originally published in 2005, and last updated in 2009.

OBJECTIVES

To determine the frequency of TNS after spinal anaesthesia with lidocaine and compare it with other types of local anaesthetics by performing a meta-analysis for all pair-wise comparisons, and conducting network meta-analysis (NMA) to rank interventions.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Elsevier Embase, and LILACS on 25 November 2018. We searched clinical trial registries and handsearched the reference lists of trials and review articles.

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials comparing the frequency of TNS after spinal anaesthesia with lidocaine to other local anaesthetics. Studies had to have two or more arms that used distinct local anaesthetics (irrespective of the concentration and baricity of the solution) for spinal anaesthesia in preparation for surgery. We included adults who received spinal anaesthesia and considered all pregnant participants as a subgroup. The follow-up period for TNS was at least 24 hours.

DATA COLLECTION AND ANALYSIS

Four review authors independently assessed studies for inclusion. Three review authors independently evaluated the quality of the relevant studies and extracted the data from the included studies. We performed meta-analysis for all pair-wise comparisons of local anaesthetics, as well as NMA. We used an inverse variance weighting for summary statistics and a random-effects model as we expected methodological and clinical heterogeneity across the included studies resulting in varying effect sizes between studies of pair-wise comparisons. The NMA used all included studies based on a graph theoretical approach within a frequentist framework. Finally, we ranked the competing treatments by P scores.

MAIN RESULTS

The analysis included 24 trials reporting on 2226 participants of whom 239 developed TNS. Two studies are awaiting classification and one is ongoing. Included studies mostly had unclear to high risk of bias. The NMA included 24 studies and eight different local anaesthetics; the number of pair-wise comparisons was 32 and the number of different pair-wise comparisons was 11. This analysis showed that, compared to lidocaine, the risk ratio (RR) of TNS was lower for bupivacaine, levobupivacaine, prilocaine, procaine, and ropivacaine with RRs in the range of 0.10 to 0.23 while 2-chloroprocaine and mepivacaine did not differ in terms of RR of TNS development compared to lidocaine. Pair-wise meta-analysis showed that compared with lidocaine, most local anaesthetics were associated with a reduced risk of TNS development (except 2-chloroprocaine and mepivacaine) (bupivacaine: RR 0.16, 95% confidence interval (CI) 0.09 to 0.28; 12 studies; moderate-quality evidence; 2-chloroprocaine: RR 0.09, 95% CI 0.01 to 1.51; 2 studies; low-quality evidence; levobupivacaine: RR 0.13, 95% CI 0.02 to 0.69; 2 studies; low-quality evidence; mepivacaine: RR 1.01, 95% CI 0.18 to 5.82; 4 studies; very low-quality evidence; prilocaine: RR 0.18, 95% CI 0.07 to 0.49; 4 studies; moderate-quality evidence; procaine: RR 0.14, 95% CI 0.04 to 0.52; 2 studies; moderate-quality evidence; ropivacaine: RR 0.10, 95% CI 0.01 to 0.78; 2 studies; low-quality evidence). We were unable to perform any of our planned subgroup analyses due to the low number of TNS events.

AUTHORS' CONCLUSIONS

Results from both NMA and pair-wise meta-analysis indicate that the risk of developing TNS after spinal anaesthesia is lower when bupivacaine, levobupivacaine, prilocaine, procaine, and ropivacaine are used compared to lidocaine. The use of 2-chloroprocaine and mepivacaine had a similar risk to lidocaine in terms of TNS development after spinal anaesthesia. Patients should be informed of TNS as a possible adverse effect of local anaesthesia with lidocaine and the choice of anaesthetic agent should be based on the specific clinical context and parameters such as the expected duration of the procedure and the quality of anaesthesia. Due to the very low- to moderate-quality evidence (GRADE), future research efforts in this field are required to assess alternatives to lidocaine that would be able to provide high-quality anaesthesia without TNS development. The two studies awaiting classification and one ongoing study may alter the conclusions of the review once assessed.

Spinal hemianesthesia: Unilateral and posterior

The injection of a non-isobaric local anesthetic should induce a unilateral spinal anesthesia in patients in a lateral decubitus position. The posterior spinal hemianesthesia only be obtained with hypobaric solutions injected in the jackknife position. The most important factors to be considered when performing a spinal hemianesthesia are: type and gauge of the needle, density of the local anesthetic relative to the CSF, position of the patient, speed of administration of the solution, time of stay in position, and dose/concentration/volume of the anesthetic solution. The distance between the spinal roots on the right-left sides and anterior-posterior is, approximately, 10-15 mm. This distance allows performing unilateral spinal anesthesia or posterior spinal anesthesia. The great advantage of obtaining spinal hemianesthesia is the reduction of cardiovascular changes. Likewise, both the dorsal and unilateral sensory block predominates in relation to the motor block. Because of the numerous advantages of producing spinal hemianesthesia, anesthesiologists should apply this technique more often. This review considers the factors which are relevant, plausible and proven to obtain spinal hemianesthesia.

[Low-dose hypobaric spinal anesthesia for anorectal surgery in jackknife position: levobupivacaine-fentanyl compared to lidocaine-fentanyl]

OBJECTIVE

To compare the percentage of patients who were able to bypass the postoperative intensive care recovery unit after selective spinal anesthesia with lidocaine-fentanyl versus levobupivacaine-fentanyl for anorectal surgery in jackknife position.

MATERIAL AND METHODS

Randomized double-blind clinical trial comparing 2 groups of 30 patients classified ASA 1-2. One group received 18 mg of 0.6% lidocaine plus 10 microg of fentanyl while the other group received 3 mg of 0.1% levobupivacaine plus 10 microg of fentanyl. Intraoperative variables were time of start of surgery, maximum extension of sensory blockade, requirement for rescue analgesics, and hemodynamic events. The level of sensory blockade was recorded at 5, 10, and 15 minutes after the start of surgery and at the end of the procedure. The degrees of postoperative motor blockade and proprioception were recorded, as were the results of the Romberg test and whether or not the patient was able to bypass the postoperative recovery unit. Also noted were times of start of ambulation and discharge, complications, and postoperative satisfaction.

RESULTS

Intraoperative variables did not differ significantly between groups, and all patients in both groups bypassed the postoperative recovery unit. Times until walking and discharge home, complications, and overall satisfaction after surgery were similar in the 2 groups.

CONCLUSIONS

Both spinal anesthetic solutions provide effective, selective anesthesia and are associated with similar rates of recovery care unit bypass after anorectal surgery in jackknife position.