Robert M. Raw

Ultrasound-guided approach for axillary brachial plexus, femoral nerve, and sciatic nerve blocks in dogs

OBJECTIVE To describe an ultrasound-guided technique and the anatomical basis for three clinically useful nerve blocks in dogs. STUDY DESIGN Prospective experimental trial. ANIMALS Four hound-cross dogs aged 2 +/- 0 years (mean +/- SD) weighing 30 +/- 5 kg and four Beagles aged 2 +/- 0 years and weighing 8.5 +/- 0.5 kg. METHODS Axillary brachial plexus, femoral, and sciatic combined ultrasound/electrolocation-guided nerve blocks were performed sequentially and bilaterally using a lidocaine solution mixed with methylene blue. Sciatic nerve blocks were not performed in the hounds. After the blocks, the dogs were euthanatized and each relevant site dissected. RESULTS Axillary brachial plexus block Landmark blood vessels and the roots of the brachial plexus were identified by ultrasound in all eight dogs. Anatomical examination confirmed the relationship between the four ventral nerve roots (C6, C7, C8, and T1) and the axillary vessels. Three roots (C7, C8, and T1) were adequately stained bilaterally in all dogs. Femoral nerve block Landmark blood vessels (femoral artery and femoral vein), the femoral and saphenous nerves and the medial portion of the rectus femoris muscle were identified by ultrasound in all dogs. Anatomical examination confirmed the relationship between the femoral vessels, femoral nerve, and the rectus femoris muscle. The femoral nerves were adequately stained bilaterally in all dogs. Sciatic nerve block. Ultrasound landmarks (semimembranosus muscle, the fascia of the biceps femoris muscle and the sciatic nerve) could be identified in all of the dogs. In the four Beagles, anatomical examination confirmed the relationship between the biceps femoris muscle, the semimembranosus muscle, and the sciatic nerve. In the Beagles, all but one of the sciatic nerves were stained adequately. CONCLUSIONS AND CLINICAL RELEVANCE Ultrasound-guided needle insertion is an accurate method for depositing local anesthetic for axillary brachial plexus, femoral, and sciatic nerve blocks.

Epidural Spread After Continuous Cervical Paravertebral Block: A Case Report

Background and Objective: This report illustrates epidural spread after continuous cervical paravertebral block (CCPVB). By fluoroscopy, it also explains the mechanism of the complication. Case Report: A healthy 22-year-old male developed bilateral upper-extremity motor weakness immediately after placement of a continuous cervical paravertebral block for postoperative pain control after shoulder stabilization surgery. The tip of the stimulating catheter was demonstrated in the C7 neuroforamen. Contrast injected through the catheter demonstrated epidural spread. The contralateral block resolved after 4 hours and the patient suffered no respiratory embarrassment or other untoward sequelae. Conclusion: Continuous cervical paravertebral block is a relatively new, but generally well-accepted, modality for postoperative pain control after major surgery to the upper limb. Epidural spread is recognized as a complication. In this particular case, medial placement of the catheter was possibly caused by unintentional medial direction of the bevel of the Tuohy needle. Meticulous attention to the direction of the needle bevel and early recognition and management of adverse events are mandatory. The same principles may apply for continuous thoracic, lumbar, and sacral paravertebral blocks.

The overpowered mega-study is a new class of study needing a new way of being reviewed.

well as the retrospective database-derived nature of the study should prompt us to ask whether or not the results justify a change in anesthesia practice? Huge studies such as this are unquestionably valuable, because they CAN detect differences in the incidence of rare events—differences that could never be detected in prospective, randomized trials—largely because performing such trials would be prohibitively difficult. However, such retrospective studies, unlike prospective trials, can never define causality, only association, and the inherent problems produced by missing data, miscoded information, and unrecognized (and hence unincorporated) covariants may be large enough to influence the reliability of any conclusions particularly when differences between groups are very small (perhaps regardless of statistical significance). A recent editorial by Collins et al.,2 commenting on a 10-million patient database study, recognized such observational mega-study limitations and emphasized the need to develop tools and consensus-based guidelines for authors, editors, and readers to better study and understand the deeper meanings and limitations of such observational analyses.3 What factors (e.g., missing covariates) might have confounded the work by Memtsoudis et al.? We believe that two critical questions are (1) why was neuraxial anesthesia chosen for any patient and (2) how was neuraxial anesthesia conducted? There are always some subtle (and perhaps not so subtle) variations in patient’s comorbidities, individual anesthesiologist and surgeon training, skills, and experience and decisionmaking processes and institutional resources of anesthesia drugs, equipment, and patient care facilities. Another recent mega-study on 367,796 patients examining viewing general surgical mortality showed patients being operated within one unitary healthcare system, but in a different hospital, could experience a significantly 30-day mortality 200% difference between best and worst scoring hospitals and this correlated with the number of intensive care unit beds available.4 The decision to use a regional anesthesia technique on an arthroplasty patient is often decided by a surgeon’s idiosyncratic likes or dislikes for regional anesthesia, similar idiosyncrasies of the anesthesiologist, the time available to perform the regional anesthetic, and finally the personal fears and preferences of the patient. Thus three parties commonly contribute to the decision to use neuraxial anesthesia or not and only one of those three parties is trained in anesthesia. Anesthetic considerations in choosing an anesthesia plan for an individual patient may be overshadowed by unscientific covariables around the anesthesia plan decision process which may in turn influence mortality directly, if only slightly. Such factors could easily influence small mortality differences in a mega-study—but would almost certainly be impossible to incorporate as covariates in the analysis. It could be also speculated that the increased use of neuraxial anesthesia is only a marker for the fact that neuraxial blocks are more likely performed by anesthesiologists more skilled in The Overpowered Mega-study Is a New Class of Study Needing a New Way of Being Reviewed

Never trust a drug that can be pronounced in three different ways: medication errors in anaesthesia

Medication errors cause patient death or injury. The worst medication errors involve patient-adverse events with an unknown medication error. This leads to wrong factors being incorrectly blamed and to the development of an illogical adverse event preventive protocol. Most medication errors cause no patient harm. There is a higher risk of medication errors occurring in paediatric than in adult anaesthesia as more drugs need to be diluted. 1

Could the Open Door Crack on Perioperative Visual Loss Be Even Bigger

men. Fixation on body mass index as the index of obesity obscures the gender difference in absolute height, also imparting a different absolute “thickness.” The combination of increased thickness and length together may contribute to significant differences in periocular congestion and edema. The Wilson frame’s absolute height may be fixed, but measurements of “thicker” and longer males will result in a greater total prone body height as measured from base (eyes) to apex (skin incision site) geometrically (Pythagorus). This is minimized by Jackson style frames, where the shoulders and hips are preferentially supported in a level position. The shortest female’s face may never reach to the base of the Wilson’s arch. Geometry has been implicated as a significant factor in vision loss in prolonged supine surgical positioning: robotic prostatectomy. Certainly the prone and head-down positions impart increased ventilation pressures to increase central venous pressure and venous pressure in the optic area, with prolonged surgery promoting intensification of edema accumulation. If we accept the geometry theory of this process, the rational conclusion to eliminate ischemic optic neuropathy is clear: Perform prolonged spinal surgery only in the left lateral position! The head is now uniformly placed above the heart, facilitating minimal venous back pressure from gravity and ventilation, while maximizing the filling pressure of the now “dependent” heart. Can geometric considerations drive a change in “routine standard neurosurgical practice?” Is the prone position primarily used for obsolete “historical reasons?” Geometry considerations have reduced sitting craniotomy numbers to an unparalleled historical minimum only by exposing the dangers of air embolism, which was also a “rare event.” Is ischemic optic neuropathy any less devastating? Can the authors examine the geometry factors in their available data because the published material is inadequate in this regard? Can surgeons be led to use the lateral position, especially for prolonged surgical procedures? What problems would be introduced or need solutions? Is it time to reexamine the premise and study this theory prospectively as optimal preventive strategy? The suggestion that staging procedures may represent a preventative strategy deserves consideration here. Staging recently has been demonstrated to impart increased morbidity and possibly mortality in major spinal surgery. The multicenter retrospective data indicate, but do not prove, that increased morbidity and mortality, prolonged hospital stay, increased costs, and infections are to be expected. It is also possible that nonarteritic ischemic optic neuropathy occurring during prone surgeries simply reflects coincidental occurrences found in the general nonsurgical population, given the relatively similar frequency of occurrence. Vasopressors commonly used during these surgeries or delayed detection in the intensive care unit with causative association to surgery may also play a role. Clearly, comparing prone to lateral surgery in a prospective fashion may be the single most effective means to improve patient outcome and clarify cause versus effect in this devastating surgical complex.

LIA-PAI for arthroplasty seems better than nothing but is it best?

In this issue of Pain Medicine , Wei Liu and XiaoHua Li studied a solution of ropivacaine, morphine, and epinephrine (adrenaline) injected intra-articularly and infiltrated peri-articularly for analgesia after hip arthroplasty [1]. They called this local and intraarticular infiltration analgesia (LIA). Related techniques are periarticular infiltration (PAI), periarticular injection, and periarticular analgesia [2–4]. The term LIA–PAI will be used here. LIA–PAI infiltration solutions contain long-acting local anesthetics commonly with additives like morphine, epinephrine (adrenaline), nonsteroidal anti-inflammatory drugs, corticosteroids, and antibiotics. Major arthroplasty is painful and causes the patient suffering [5]. Poorly treated pain contributes to impaired physical rehabilitation, immobility-associated complications such as pneumonia and deep venous thrombosis, stress-precipitated cardio- and cerebro-vascular …

Regional Anesthesia for Breast Surgery

When a woman receives a diagnosis of breast cancer, concerns naturally turn towards survival, closely followed by the physical discomfort of treatment. These can emerge from surgical care, systemic therapies, as well as radiotherapy. The anesthesiologist can play an important role in minimizing discomfort during surgical care. For example, the woman who has undergone the physical loss of her breast through a mastectomy is spiritually injured as well. The first treatment of her spirit starts with providing maximal pain relief. No woman whose femininity and beauty are injured by necessary therapies needs to also suffer physical pain. Regional anesthesia, by offering total physical pain relief, can also be the start of spiritual pain relief. Regional anesthesia also offers decreased opiate requirements as this may fully abolish postoperative nausea.

Reply to Dr. Baumgarten

1. Boezaart AP, Raw RM. Sleeping beauty or big bad wolf? Reg Anesth Pain Med 2006;31:189-191. 2. Reisner LS, Hochman BN, Plumer MH. Persistent neurologic deficit and adhesive arachnoiditis following intrathecal 2-chloroprocaine injection. Anesth Analg 1980;59:452454. 3. Albright GA. Cardiac arrest following regional anesthesia with etidocaine or bupivacaine. Anesthesiology 1979;51: 285-287. 4. Covino BG, Wildsmith JAW. Clinical pharmacology of local anesthetic agents. In: Cousins MJ and Bridenbaugh PO, eds. Neural Blockade in Clinical Anesthesia and Management of Pain. 2nd ed. Philadelphia, PA: Lippincott-Raven; 1998: 117. 5. Van Zundert A, Vaes L, Soetens M, De Vel M, Van der Aa P, Van der Donck A, Meeuwis H, De Wolf A. Every dose given in epidural analgesia for vaginal delivery can be a test dose. Anesthesiology 1987;67:436-440. 6. Greengrass R, Steele S. Paravertebral blocks for breast surgery. Tech Reg Anesth Pain Manage 1998;2:8-12. 7. Kairaluoma PM, Bachmann MS, Korpinen AK, Rosenberg PH, Pere PJ. Single-injection paravertebral block before general anesthesia enhances analgesia after breast cancer surgery with and without associated lymph node biopsy. Anesth Analg 2004;99:1837-1843. 8. Baumgarten RK, Thompson GE. Is ultrasound necessary for routine axillary block? Reg Anesth Pain Med 2006;31:8889; author reply 89-90.