The August 2013 issue of Anesthesia and Analgesia has just posted. Highlights of this issue of the journal include:
· Is lidocaine a general anesthetic? Hamp and colleagues (The Effect of a Bolus Dose of Intravenous Lidocaine on the Minimum Alveolar Concentration of Sevoflurane: A Prospective, Randomized, Double-Blinded, Placebo-Controlled Trial) found that 1.5 mg/kg of IV lidocaine reduced the MAC of sevoflurane from 1.86% to 1.63% on average.
· In a multicenter observational trial Kotake and colleagues (Reversal with Sugammadex in the Absence of Monitoring Did Not Preclude Residual Neuromuscular Block) studied recovery in patients receiving rocuronium without neuromuscular monitoring. Although sugammadex reduced the incidence of inadequate reversal (TOFR < 0.9) compared to neostigmine, 4% of patients receiving sugammadex had inadequate reversal. The accompanying editorial by Naguib and colleagues (Residual Block after Sugammadex) explores reasons why anesthesiologists fail to monitor muscle strength and observes that sugammadex does not obviate the need for neuromuscular monitoring.
· Ethosomes are liposomes with an unusually high ethanol content, which enhances vesicular deformability and increases intradermal penetration. Zhu and colleagues (Formulation and Evaluation of Lidocaine Base Ethosomes for Transdermal Delivery) examined the ability of ethosomes to deliver lidocaine across the skin. Ethosomes delivered up to five times as much lidocaine as liposomes, resulting in more profound and longer lasting cutaneous analgesia.
· In a propensity matched cohort study of 22,851 patients, McCluskey and colleagues (Hyperchloremia After Noncardiac Surgery Is Independently Associated with Increased Morbidity and Mortality: A Propensity-Matched Cohort Study) examined the relationship between postoperative hyperchloremia (chloride > 110 mEq/L) and outcome. At 30 days hyperchloremic patients were at increased risk of mortality (odds ratio = 1.58), increased hospital duration, and renal failure. In their accompanying editorial, Butterworth and Mythen (Normal Saline and Hyperchloremia) suggest that “until an adequately powered randomized clinical trial proves us wrong, 0.9% saline will not be our crystalloid of choice.”
· Local anesthetics are frequently injected into joint tissues following surgery. In a disturbing study with cultured human chondrocytes, Breu and colleagues (The Cytotoxicity of Bupivacaine, Ropivacaine, and Mepivacaine on Human Chondrocytes and Cartilage) found that bupivacaine, ropivacaine, and mepivacaine are chondrotoxic, with toxicity increasing with anesthetic concentration and duration of exposure.
Then, there’s the cover article, by Albrecht and colleagues, (Patient Warming Excess Heat: The Effects on Orthopedic Operating Room Ventilation Performance). How appropriate that we discuss the concept of perioperative thermoregulation in the month of August. Here in the United States we find ourselves amidst the heat of the summer season. As radiant photons bombard the metal exoskeleton of our hospital, brand new trainees thrive in the most embryonic phase of their career in the cold of the operating room. One such resident doctor holds the hose of a forced air warming device and I watch as he forcibly cork-screws it into the blanket’s receiving port. The previously dormant sheet billows forth into life embracing the patient with warmth. Still in the blissful wake of a successful tracheal intubation, this young physician likely does not yet appreciate incongruent forces that impose themselves on the less-than-glamorous task of rewarming our functionally poikilothermic patient. It would appear nothing less than logical to give back what we have taken away. The articles and editorial responses in this month’s issue cast this logic into the mire of doubt as we seek to appraise the risks and benefits of even the simplest restorative measures.
These articles and more will be covered in the coming month by AA2day.