Evaluating Patterns of Injectate Spread After Rectus Sheath Block: A Cadaveric Dissection Study.

INTRODUCTION: This cadaveric dye study assesses the effect of volume and number of injections on the spread of solution after ultrasound-guided rectus sheath injections. In addition, this study evaluates the impact of the arcuate line on solution spread. MATERIALS AND METHODS: Ultrasound-guided rectus sheath injections were performed on seven cadavers on both sides of the abdomen, for a total of 14 injections. Three cadavers received one injection of 30 mL of a solution consisting of bupivacaine and methylene blue at the level of the umbilicus. Four cadavers received two injections of 15 mL of the same solution, one midway between the xiphoid process and umbilicus and one midway between the umbilicus and pubis. RESULTS: Six cadavers were successfully dissected and analyzed for a total of 12 injections, while one cadaver was excluded due to poor tissue quality that was inadequate for dissection and analysis. There was a significant spread of solution with all injections caudally to the pubis without limitation by the arcuate line. However, a single 30 mL injection showed inconsistent spread to the subcostal margin in four of six injections, including in a cadaver with an ostomy. A double injection of 15 mL showed consistent spread from xiphoid to pubis in five of six injections, except in a cadaver with a hernia. CONCLUSIONS: Injections deep to the rectus abdominis muscle, using the same technique as an ultrasound-guided rectus sheath block, achieve spread along a large and continuous fascial plane without limitation by the arcuate line and may provide coverage of the entire anterior abdomen. A large volume is necessary for complete coverage and spread is improved with multiple injections. We suggest that two injections with a total volume of at least 30 mL per side may be needed to achieve adequate coverage in the absence of preexisting abdominal abnormalities.

Pneumothorax Following Breast Surgery at an Ambulatory Surgery Center.

Pneumothorax is a known complication following breast surgery but is likely underappreciated by anesthesiologists. Iatrogenic pneumothorax can be caused by needle injury during local anesthetic injection, surgical damage to the intercostal fascia or pleura, or pulmonary injury from mechanical ventilation. We present two cases of pneumothorax following bilateral mastectomy with bilateral pectoral blocks and immediate breast reconstruction. Both cases occurred at a freestanding ambulatory surgery center in patients with no history of lung disease. One patient was found to have bilateral pneumothoraxes after complaining of shortness of breath and chest pain in the post-operative care unit. The second patient was asymptomatic but found to have a right-sided pneumothorax on a chest X-ray (CXR) that was ordered to rule-out left-sided pneumothorax due to concern of intraoperative breach of the left chest wall. Both patients were treated with chest tubes, transferred to a nearby hospital, and discharged several days later. Anesthesiologists must be aware of this potentially life-threatening complication and consider pneumothorax in the differential diagnosis of perioperative hypoxemia, shortness of breath, chest pain, and hemodynamic collapse in patients undergoing breast surgery. Though traditionally diagnosed via radiograph, pneumothorax can be rapidly diagnosed with ultrasound. Tension pneumothorax should be decompressed immediately with a needle. A clinically significant, non-tension pneumothorax is treated with chest tube placement. Equipment necessary to treat pneumothorax should be available for emergency treatment in facilities wherever breast surgery is performed.

Anesthetic Challenges Posed by Heavy Kratom Users.

Kratom is a herbal and natural dietary supplement from Southeast Asia that is gaining popularity in the United States. Its leaves contain multiple psychoactive chemicals that stimulate opioid, alpha-2, and serotonergic receptors. Kratom is used as a stimulant and in the treatment of anxiety, pain, and opioid withdrawal. In most states, kratom can be purchased legally and is sold at smoke shops, gas stations, and online. To date, only limited data is available on the impact of habitual kratom use on patients undergoing anesthesia. The following case report highlights multiple anesthetic challenges posed by a heavy kratom user.

COVID-19 mRNA Vaccination, ABO Blood Type and the Severity of Self-Reported Reactogenicity in a Large Healthcare System: A Brief Report of a Cross-Sectional Study.

Introduction It has been anecdotally observed that ABO blood type may have an impact on the severity of the side-effects experienced by those receiving mRNA vaccination for COVID-19.  Methods As part of a larger study, a retrospective cross-sectional survey was made available to approximately 33,000 front-line healthcare workers, students and volunteers who were offered voluntary vaccination in a state-wide healthcare system during phase one of the state's vaccine roll-out. A secondary endpoint of the survey was to determine if there was any relationship between vaccination reactogenicity and ABO blood type.  Results 4009 responses were received - a 12.15% response rate. 3700 respondents answered the blood type question, and of those, 2878 knew their blood type. By Kruskal-Wallis test, there was no statistically significant association between any blood type and any side effect for either of the COVID-19 mRNA vaccines.  Conclusions COVID-19 mRNA vaccination may cause significant reactogenicity. However, ABO blood type does not appear to be a predictor of vaccine reactogenicity.