Comparison of circulatory and respiratory responses between supplementary epidural buprenorphine and eptazocine administration during and immediately after total intravenous anesthesia

Opioid supplements are often required in total intravenous anesthesia (TIVA). Most ϰ-opiate receptors are found in the spinal cord, wherea μ-opiate receptors are widespread throughout the brain and spinal cord. Buprenorphine has a strong μ-action with a minute ϰ-action, while eptazocine stimulates ϰ-receptors only. From these, epidural eptazocine is expected to exert strong spinal analgesia by ϰ-stimulation without μ-action, which produces circulatory and respiratory depression. Therefore, the clinical effects of epidural opioids on circulation, respiration, and analgesia were compared. Continuous epidural administration of eptazocine or buprenorphine was combined with TIVA in patients scheduled for elective abdominal surgery. Epidural opioid administration was continued throughout and for 72h after anesthesia. A significant analgesic effect (P<0.01) of epidural eptazocine without circulatory and respiratory depression was observed. With epidural buprenorphine, circulatory and respiratory depression during and immediately after anesthesia were significant (P<0.05). These results suggest that medullary μ-stimulation by an epidural opioid induces circulatory (hypervagotonicity and hypervagosensitivity) and respiratory depression, while ϰ-stimulation produces only minimal effects on circulatory and respiratory systems.     

Our Distal Aortic Perfusion System in Descending Thoracic and Thoracoabdominal Aortic Aneurysm Repairs

Abstract: We have used heparin-bonded partial cardio-pulmonary bypass to support distal aortic circulation during aortic cross-clamping. However, there were no cardiotomy reservoirs with fully reliable thromboresistance. To resolve this problem, a short-acting anticoagulant (nafamostat mesilate) was added into a cardiotomy reservoir. The present study was designed to evaluate the efficacy of our distal perfusion system. From May 1995 through the end of May 1996, 27 patients underwent descending thoracic and thoracoabdominal aortic aneurysm repairs with this adjunct, 4 being excluded from the experiment. Twenty patients who had undergone conventional partial cardiopulmonary bypass were defined as the control group. There were no significant differences between the 2 groups in the morbidity, mortality, gas transfer, or transfusion requirements despite the fact that more complicated surgical procedures (shown by a two-fold increase in the prevalence of reoperation) were required in the group that had received the current distal perfusion adjunct. the heparin-bonded group. In conclusion, our perfusion system is very effective for descending thoracic and thoracoabdominal aortic aneurysm repairs.     

Microsurgical and magnetic resonance imaging anatomy of the cerebello-medullary fissure and its application during fourth ventricle surgery.

The cerebellomedullary fissure, the only entrance or exit to the fourth ventricle, is surrounded rostrally by the cerebellar tonsils and the biventral lobules and caudally by the medulla oblongata, the tela choroidea, and the lateral recesses. This fissure is an important route in operations on the fourth ventricle. We studied the microsurgical and magnetic resonance imaging (MRI) anatomy of the fissure by using autopsied normal cerebellum. MRI revealed that the fissure is visible as a slit and is indicated by the enhanced choroid plexus and the flocculus. Oriented by the anatomical information thus obtained, we have surgically treated nine patients with a tumor either in or around the fourth ventricle. Preoperative MRI clearly demonstrated the tumors in relation to the cerebellomedullary fissure. It revealed the precise anatomical location and extension of the tumor, not only its inferior extension but also its lateral one. The MRI findings and microsurgical anatomy of the cerebellomedullary fissure were quite useful for the removal of the tumors in the fourth ventricle.     

Hyperthermo-chemo-radiotherapy as a definitive treatment for patients with early esophageal carcinoma.

Ten patients with early stage esophageal carcinoma were treated with hyperthermo-chemo-radiotherapy (HCR) without surgery. The reasons for the inoperability of these patients included medically inoperable unresectable cancers, advanced age, and/or refusal to undergo surgery. The diagnosis of early esophageal carcinoma was determined by esophagograms, endoscopy, and ultrasonography. Squamous cell carcinoma was histopathologically confirmed in each case. Each patient underwent four to nine sessions of hyperthermic treatment combined with external irradiation and chemotherapy using bleomycin; eight of these patients received additional radiation, and two terminated treatment after the HCR therapy. The tumors in all patients showed either a complete response (CR) or a partial response (PR) after HCR therapy; in two patients viable cancer cells remained, but later disappeared after additional radiation. Five patients experienced no local recurrence for 12 to 70 months and are now alive and doing well, three died of other medical conditions without any evidence of esophageal cancer, and two died of recurrent esophageal cancer 20 to 27 months after initial admission. All ten patients tolerated the HCR well without any systemic side effects. However, in two patients, esophageal erosion was recognized endoscopically. HCR therapy therefore deserves serious consideration when treating patients with small malignant lesions of the esophagus who, for various reasons, are unable to undergo surgery.     

The relation between EEG and mental development following cardiac surgery performed under simple deep hypothermia in children

In order to assess the accuracy of electroencephalography (EEG), in children who have undergone cardiac surgery under simple deep hypothermia, the relation between IQ or schoolwork achievement and the duration of circulatory arrest was investigated in 75 such children. Abnormal preoperative EEG's were found in 16 per cent of the children while abnormal postoperative EEG's were found in 17 per cent. The children were divided into 4 groups, according to pre- and postoperative EEG results. Schoolwork achievement scores ranged between 3.0 and 3.2, the difference among the groups being insignificant. Moreover, no significant shift in IQ was found among the groups. Finally, regarding the number of children who were able to go on to a higher level of education, including high school the college or university, again no significant differences were found among the 4 groups. In a comparison with the number of such children in neighboring Nagasaki prefecture able to continue on to a higher level of education, no significant differences were seen either. The findings and statistics of this investigation therefore indicate that pre- and postoperative EEG's are not always a reliable reference for assessing the prognosis of cerebral activity.     

Middle-ear pressure variations during total intravenous anesthesia with propofol, fentanyl, and ketamine

Purpose As the middle-ear cavity is one of the noncompliant gas-filled cavities, an increase in middle-ear pressure (MEP) instead of volume expansion is observed with inhalation of nitrous oxide (N₂O). Changes in MEP cause many complications, such as ear pain, temporary hearing impairment, and postoperative emesis. Therefore, we investigated changes in MEP during total intravenous anesthesia (TIVA) with propofol, fentanyl, and ketamine (PFK) and inhalation of N₂O. Methods Twelve patients were anesthetized with PFK until 60 min after the induction of anesthesia, and then N₂O (60%) inhalation was started. MEP was measured by impedance audiometry (ranging from −300 daPa to +200 daPa) at 10-min intervals during PFK, and at 2-min intervals after the inhalation of N₂O. Results MEP gradually but significantly increased from the preanesthetic value of 16±8 to 34±12 (SEM) daPa 50 min after the induction of PFK. However, MEP did not exceed the normal limit. The values of MEP in all patients were more than 200 daPa within 36 min after the start of inhalation of N₂O in oxygen. Conclusion PFK had a minimal effect on MEP, whereas addition of N₂O to PFK increased MEP dramatically. Therefore, TIVA, or at least PFK, would be a better choice for patients with middle-ear or upper-airway diseases.     

Hepatic angiomyolipoma developing during the follow-up of ulcerative colitis: Report of a case and review of the literature

Hepatic angiomyolipoma is a rare tumor composed of spindle-shaped and epithelioid smooth muscle cells, adipose tissue, and proliferating blood vessels. We report the first documented case of this tumor developing in a patient with ulcerative colitis. A solitary tumor (7.5×7.5×7cm) was detected in the left lateral segment of the liver and a left hepatic lobectomy was performed. The diagnosis of angiomyolipoma was confirmed by a pathological examination. We also review the literature on previously reported cases of hepatic angiomyolipoma.