Hideki Mamiya

Negative Pressure Pulmonary Edema After Oral and Maxillofacial Surgery

Negative pressure pulmonary edema (NPPE) following upper airway obstruction (UAO) has been reported in several clinical situations. The main cause of NPPE is reported to be increased negative intrathoracic pressure. We present a case of NPPE that occurred after general anesthesia for plate removal after jaw deformity surgery. After completion of the surgery, administration of inhaled anesthetics was stopped and the patient opened his eyes on verbal command. Immediately after extubation, the patient stopped breathing and became cyanotic. Acute UAO following laryngospasm was suspected. Soon after reintubation, pink, frothy fluid came out of the endotracheal tube, and a tentative diagnosis of NPPE was made. Continuous positive airway pressure was applied. In addition, furosemide and dexamethasone were administered. By the next day, the symptoms had almost disappeared.

The Characteristics of Intravenous Adenosine-Induced Antinociception in a Rabbit Model of Acute Nociceptive Pain: A Comparative Study with Remifentanil

BACKGROUND:Adenosine and remifentanil are potent IV analgesics with ultrashort half-lives. The antinociceptive effect of IV adenosine has not been clearly characterized. We compared the antinociceptive effects of adenosine and remifentanil in rabbits. METHODS:Sixteen rabbits, placed on a sling allowing reasonably free movement, received IV adenosine (400 &mgr;g · kg−1 · min−1) or remifentanil (0.4 &mgr;g · kg−1 · min−1) over 240 min. RESULTS:Both drugs produced profound antinociception, as assessed by the number of animals unresponsive to clamping the forepaw and the electrical stimulation threshold of escape movement. With remifentanil, the antinociceptive effect increased rapidly, reaching its peak at 60 min, and then began to decline despite continued infusion. After stopping the infusion, it decreased rapidly and disappeared within 30 min. The vasodilating effect of IV adenosine was immediate in onset and ultrashort in duration. The antinociceptive effect of adenosine increased slowly but progressively during the infusion, reaching its peak only when the infusion ended. Then it decreased slowly over the following 360 min after terminating the infusion. CONCLUSION:Remifentanil had a rapid onset and short duration of action, and probably showed signs of tolerance development, whereas the antinocieptive effect of adenosine was slow in onset and long-lasting, despite its ultrashort plasma half-life and the immediate on–off profiles of its vasodilating effect.

Localization of 14C-labeled 2% lidocaine hydrochloride after intraosseous anesthesia in the rabbit.

OBJECTIVE The purpose of this study was to investigate the tissue distribution of lidocaine hydrochloride in mandibular bone marrow after intraosseous anesthesia (IOA) in rabbits. METHODS We used macroautoradiography to examine the tissue distribution of a (14)C-labeled 2% lidocaine hydrochloride solution containing 1:80,000 epinephrine ((14)C-lidocaine). Under general anesthesia, (14)C-lidocaine was injected intraosseously or paraperiosteally. After IOA, animals were divided into three groups and observed at 1 (IOA-1), 5 (IOA-5), and 10 minutes (IOA-10) after injection. After infiltration anesthesia (IA), animals were observed at 1 minute after injection. RESULTS The accumulation of (14)C-lidocaine was observed around the injection site in both the IA and the IOA groups. Paraperiosteally injected (14)C-lidocaine diffused to the surrounding tissues such as the lip, whereas IOA showed concentrated accumulation around the root apex throughout the experiment. The distribution area was significantly smaller in the IOA-1 group than in the IA group. The distribution area in the IOA-5 group was larger than those in the IOA-1 and IOA-10 groups. CONCLUSIONS The accumulation of (14)C-lidocaine injected by IOA in rabbits was concentrated around the root apex. These results may explain the rapid onset time of IOA.