Inadequate control of postoperative pain remains a major clinical problem. A reliable method of providing long-lasting postoperative analgesia with a single dose would be very useful. We synthesized a liposomal morphine formulation and compared it to free morphine with regard to duration of analgesia in the mouse. Analgesia was assessed after intraperitoneal injection using the tail-flick test. The systemic toxicity after administration of liposomal and free morphine was compared. The release rate of morphine from liposomes in vitro was also evaluated. The lethal intraperitoneal dose of free morphine in 50% of mice (LD50) was 400 mg/kg. The maximum safe (non-lethal) dose of free morphine was 130 mg/kg. The highest dose of liposomal morphine administered (1650 mg/kg) did not cause death in any animal. Duration of analgesia was significantly prolonged with the highest dose of liposomal morphine (21.5 +/- 5.3 h) compared to the maximum safe dose of free morphine (3.7 +/- 0.75 h), P < 0.01. In vitro experiments showed a slow release rate of morphine from the liposome depot. Prolonged analgesia and decreased systemic toxicity for liposomal morphine are explained by sustained release of morphine from the liposomal depot. These results suggest that liposomal narcotic formulations may provide prolonged analgesia with single-dose administration.

For spinal anesthesia in patients undergoing ambulatory knee arthroscopy, chloroprocaine has the shortest time to complete recovery of sensory and motor block compared with bupivacaine and lidocaine.

Introduction: During upper airway surgery in a narrowed airway due to tumor or stenosis, safe ventilation, good laryngotracheal exposure, and preservation of an adequate surgical working space are of paramount importance. This can be achieved by small-lumen ventilation such as High Frequency Jet Ventilation (HFJV). However, this technique has major drawbacks, such as air-trapping and desaturation in patients with poor pulmonary reserve. Recently, an innovative ventilating system with flow-controlled ventilation (FCV) and a small-lumen endotracheal tube, the Evone ® (Ventinova, Eindhoven, The Netherlands), was introduced, claiming to counter the drawbacks of HFJV.Objectives: To evaluate feasibility and safety of the Evone ® FCV system in difficult upper airway surgery and to critically appraise this novel ventilation method.Patients and methods: Evone ® is a FCV-device using a small-bore cuffed tube (Tritube ® ). This ventilator actively sucks air out of the lungs, rather than relying on the passive backflow of air like in HFJV. Data related to the medical history, surgery, and anesthesia of all consecutive patients undergoing upper airway surgery with Evone ® FCV ventilation were included in a tertiary center retrospective observational study.Results: Fifteen Patients, with a median age of 54 years, were included. Surgical procedures and indications included laser-assisted endoscopic treatment of idiopathic subglottic stenosis (n = 3), tracheal stenosis (n = 1), and posterior glottic stenosis (n = 2), biopsy and/or Transoral Laser Microsurgery for laryngeal (pre)malignancy (n = 7) and resection of benign lesions with posterior (supra)glottic location (n = 2). Mean ventilation duration was 52.0 min (range 30-115 min, SD 19.6 min), mean surgery duration was 31.7 min (range 15-65 min, SD 13.2 min), mean minimal SaO 2 was 96.3% (range 89-100%, SD 4.0%) and mean peak pCO 2 was 41.4 mmHg (range 31-50 mmHg, SD = 5.5 mmHg). No anesthesia-or surgery-related complications, adverse events or intra-operative difficulties were reported during or after any of the 15 procedures. In all cases, compared to HFJV, Evone ® FCV ventilation allowed a superior visualization and working space during the surgical procedure.Meulemans et al. Evone ® During Upper Airway SurgeryConclusion: The Evone ® FCV ventilation system provides excellent conditions in patients undergoing upper airway surgery, as it combines excellent accessibility and visibility of the operation site with safe and stable ventilation.