Spinal Anaesthesia as an Adjunct to General Anaesthesia for Laparoscopic Abdominoperineal Rectal Amputation

Background

Spinal anaesthesia as an adjunct to general anaesthesia may reduce postoperative pain and opioid consumption after laparoscopic abdominoperineal rectal amputation. We designed a randomized double blinded pilot study with two objectives: 1) to explore potential benefits of spinal anaesthesia as an adjunct to general anaesthesia and 2) to provide power and sample size estimations for potential differences between the groups. Primary outcome measures were postoperative pain and oral morphine equivalent (OMEq) consumption.

Methods

Patients scheduled for elective laparoscopic abdominoperineal rectal amputation at the University Hospital of North Norway were randomised to spinal (n=5) or a sham spinal procedure (n=5). Numeric rating scale (NRS) and OMEq were monitored postoperatively for 72 h.

Results

Age, sex, body mass index, and ASA were not significantly different between the groups. During surgery, patients in the spinal group received less remifentanil (p=0.06). NRS was lower in the spinal group 1 hr after admittance to the post-anaesthesia care unit (PACU) (p=0.06) and on the first postoperative day at 8 AM (p=0.03). OMEq consumption in the PACU was lower in the spinal group (p=0.008), but no differences between the groups were detected after discharge to the ward. Sample size estimations revealed that eight patients in each group would be needed to study potential NRS differences after admission to the PACU and 23 patients in each group to study potential differences in OMEq consumption on day 1.

Conclusion

Spinal anaesthesia as an adjunct to general anaesthesia reduces postoperative pain and opioid consumption after laparoscopic abdominoperineal rectal amputation. Data from the current study should be followed up by a sufficiently powered randomized controlled trial.

Clinical Trial Registration

Trial registered at https://clinicaltrials.gov (NCT05406765).

Incidence and related factors for intraoperative failed spinal anaesthesia for lower limb arthroplasty

BACKGROUND

Spinal anaesthesia is the preferred choice for total hip- and knee arthroplasty (THA/TKA), due to the claimed superior outcome profile, relative simple technique and without the need for advanced airway support. However, choosing and informing about spinal anaesthesia should also include the risk for intraoperative failed spinal anaesthesia with associated pain, discomfort and suboptimal settings for airway management. Small-scale studies suggest incidences from 1 to 17%; however, no multi-institutional large data exists on failed spinal incidence and related factors during THA/TKA, hindering evidence-based information and potential anaesthesia stratification.

METHODS

In a sub-analysis, data from a prospective study on spinal anaesthesia for THA/TKA were examined for incidence of intraoperative conversion to general anaesthesia. Potential perioperative factors (age, gender, American Society of Anaesthesiologist (ASA) score, height, weight, BMI, procedure, bupivacaine dosage and duration of time from spinal administration until end of surgery) were analysed with logistic regression for relation to failed spinal anaesthesia.

RESULTS

In all, 1451 patients were included for analysis, whereof 57 (3.9%) had failed spinal anaesthesia. Spinal failure patients were significantly younger (61 vs. 67 years, P = 0.003), and operation time longer in the failed spinal group vs no-failure, respectively (133 vs. 89 min, P < 0.001). No significant differences were found with regard to bupivacaine volume, gender, ASA-score, height, weight, BMI or THA vs. TKA.

CONCLUSION

Failed spinal anaesthesia for THA and TKA is a relatively frequent occurrence and identification of risk patients is not feasible. These results should be considered when choosing anaesthesia and included in the information to patients.

Approach to failed spinal anaesthesia for caesarean section

Failure of spinal anaesthesia for caesarean section may have deleterious consequences for the mother as well as the newborn baby. In this article, we discuss the mechanisms of failure of spinal anaesthesia as well as the approach to a failed block. We performed a literature search in Google Scholar, PubMed, and Cochrane databases for original and review articles concerning failed spinal anaesthesia and caesarean section. Strategies for a failed spinal anaesthetic include manoeuvers to salvage the block, repeating the block, epidural anaesthesia or a combined spinal-epidural (CSE) technique, or resorting to general anaesthesia. Factors influencing the choice of these alternative options are discussed. A "failed spinal algorithm" can guide the anaesthesiologist and help reduce morbidity and mortality.

Total Spinal Anesthesia Failure: Have You Assessed the Sensory Anesthesia in Sacral Dermatomes?

Intrathecal local anesthetic maldistribution is a well-known cause of spinal anesthesia failure (SAF). This could potentially result in sensory blockade restricted to the sacral dermatomes. We sought to determine the overall incidence of SAF and the role of sacral dermatomes in differentiating between total and partial failures. Of the 3111 spinals prospectively examined, 194 (6.2%) were classified as failures. Of the 72 presumed total failures based on the initial assessment, evaluation of the sacral dermatomes revealed sensory blockade in 32 (44%; 95% confidence interval, 32.7%-56.6%). Sacral dermatome assessment after SAF may be important in safely guiding subsequent anesthetic management.

Understanding pharmacokinetics using realistic computational models of fluid dynamics: biosimulation of drug distribution within the CSF space for intrathecal drugs

We introduce how biophysical modeling in pharmaceutical research and development, combining physiological observations at the tissue, organ and system level with selected drug physiochemical properties, may contribute to a greater and non-intuitive understanding of drug pharmacokinetics and therapeutic design. Based on rich first-principle knowledge combined with experimental data at both conception and calibration stages, and leveraging our insights on disease processes and drug pharmacology, biophysical modeling may provide a novel and unique opportunity to interactively characterize detailed drug transport, distribution, and subsequent therapeutic effects. This innovative approach is exemplified through a three-dimensional (3D) computational fluid dynamics model of the spinal canal motivated by questions arising during pharmaceutical development of one molecular therapy for spinal cord injury. The model was based on actual geometry reconstructed from magnetic resonance imaging data subsequently transformed in a parametric 3D geometry and a corresponding finite-volume representation. With dynamics controlled by transient Navier–Stokes equations, the model was implemented in a commercial multi-physics software environment established in the automotive and aerospace industries. While predictions were performed in silico, the underlying biophysical models relied on multiple sources of experimental data and knowledge from scientific literature. The results have provided insights into the primary factors that can influence the intrathecal distribution of drug after lumbar administration. This example illustrates how the approach connects the causal chain underlying drug distribution, starting with the technical aspect of drug delivery systems, through physiology-driven drug transport, then eventually linking to tissue penetration, binding, residence, and ultimately clearance. Currently supporting our drug development projects with an improved understanding of systems physiology, biophysical models are being increasingly used to characterize drug transport and distribution in human tissues where pharmacokinetic measurements are difficult or impossible to perform. Importantly, biophysical models can describe emergent properties of a system, i.e. properties not identifiable through the study of the system’s components taken in isolation.