Time-dependent changes in epidural catheter aspirate after injection of a local anesthetic.

STUDY OBJECTIVE: A glucose check is used for investigation of a suspected accidental dural puncture in epidural anesthesia. However, glucose-positive clear fluid is sometimes aspirated from an epidural catheter in cases without clinical evidence of puncture. The goal of the study was to investigate time-dependent changes in the aspirate composition after injection of a local anesthetic into the epidural space. DESIGN: Observational study. SETTING: Operating rooms at Hamamatsu University Hospital. PATIENTS: The subjects were 30 patients (ASA I or II) undergoing surgery with combined epidural and general anesthesia. INTERVENTIONS: After epidural injection of local anesthetics, aspiration through the catheter was performed every 10min until fluid could not be aspirated. pH, Na, K, Cl, Ca and glucose were measured in fluid samples using a blood gas analysis apparatus. MAIN RESULTS: No patients had pain or clinical signs suggesting dural puncture throughout the perioperative period. Fluid aspiration was possible in 15 patients (50%) after 10min and in 7, 3, 2 and 2 patients after 20, 30, 40 and 50min, respectively. Glucose was detected in each aspirated fluid sample and gradually increased with time to become closer to the level in cerebrospinal fluid (CSF). Each electrolyte also changed to approach the level found in CSF. CONCLUSIONS: A glucose check may increase the risk of a false-positive finding for accidental dural puncture with increasing time after local anesthetic injection. Conversely, detection of glucose at the time of epidural catheter placement may provide useful information for detection of accidental dural puncture.

[The Effectiveness of Two Anesthesia Machines in the Water Generation of the Anesthesia Circuit during the Prolonged Low Flow Desflurane Anesthesia].

BACKGROUND: Water is generated by a reaction of carbon dioxide and a carbon dioxide absorbent We evaluated the effectiveness of the anesthesia machines about the water generation which occurs to an anes- thetic circuit during the prolonged low flow anesthesia. METHODS: Fifteen patients were divided into three groups; group HHS (n=5) in which a hot heater system was equipped inside anesthesia machine, group WCD (n=5) in which a water catchment device was connected with anesthesia machine, and control group N(n=5)in which normal anesthesia machine was used without special device, and studies were performed with FGF 11 - min- low flow desflurane anesthesia for more than 6 hours. The water situation in an anesthe- sia circuit was observed during the operation and was compared after the operation between these groups. RESULTS: In an anesthesia circuit of the anesthesia machines inside there was no water in group HHS and WCD, but more water in group N. In an anesthesia circuit of the anesthesia machines outside there was little water in group WCD, but more water in group HHS and N. CONCLUSIONS: Two anesthesia machines, group HHS and WCD, were effective about reduction of water generation in an anesthesia circuit of the anesthesia machines inside during FGF 11 - min-I prolonged low flow desflurane anesthesia.

[Nasogastric tube syndrome suspected at the end of anesthesia].

The case of a patient who might have developed nasogastric tube syndrome at the end of anesthesia is presented. A 62-year-old woman was scheduled for a general anesthesia with fiberscopic oro-tracheal intubation because of a predicted difficult airway. After the smooth and gentle intubation without any trauma and injury, a nasogastric tube was inserted blindly. At the end of surgery, the anesthesiologists observed the pharyngeal tissue and found significant edema on the epiglottis and arytenoids. Extubation was cancelled and the patient was moved to an intensive care unit for respiratory management. On the next day, fiberscopic observation revealed a complete recovery and the endotracheal tube was removed without any difficulty. We strongly suspected the pharyngeal injury as acute nasogastric tube syndrome and an attention to this rare complication is required by anesthesiologists.