Suppressive effects of volatile anesthetics on cytokine release in human peripheral blood mononuclear cells

This study investigated the effects of three volatile anesthetics (sevoflurane, isoflurane, and enflurane) on cytokine release by human peripheral mononuclear cells (PBMCs) stimulated by natural killer (NK)-sensitive tumor cells, K562, in vitro. PBMCs, as effector cells, obtained from 31 volunteers were randomly allocated to two groups in the first set of experiments. One group was incubated with K562 (n = 21) and the other with medium alone as a control (n = 10). In a second set of experiments, PBMCs from each volunteer (n = 21) were divided into three groups: nonanesthetic, 1.5-MAC, and 2.5-MAC groups (n = 7 for each anesthetic). After 2 h exposure to anesthetic gas or air, K562 cells were added to the effector cells. After 4 h incubation, interleukin-1 beta (IL-1 beta), interleukin-2 (IL-2), tumor necrosis factor-alpha (TNF-alpha), and interferon-alpha (INF-alpha) in the supernatant were assayed. IL-1 beta and TNF-alpha levels were significantly increased in comparison with those in the control group. IL-2 levels tended to be higher than those in the control group. No effect on IFN-alpha levels was found. After anesthetic exposure, the releases of IL-1 beta and the release of TNF-alpha were significantly inhibited compared with those after air exposure. None of the anesthetics inhibited IL-2 release. The anesthetics studied are capable of altering the release of cytokines by NK and NK-like cells in response to tumor cells.

An inhibitor of nitric oxide synthase, N omega-nitro-L-arginine-methyl ester, attenuates hypotension but does not improve cardiac depression in anaphylaxis in dogs

We investigated whether a nitric oxide synthase (NOS) inhibitor improves cardiovascular depression associated with anaphylaxis. After induction of anaphylactic circulatory depression, one group received an NOS inhibitor (Group I, n = 6) and the other received saline solution (Group II, n = 5). Mean arterial pressure and right atrial pressure were significantly higher in Group I than in Group II. Hematocrit was significantly lower in Group I than in Group II. Cardiac output, stroke volume, mean pulmonary arterial pressure, the maximum rate of increase in left ventricular pressure, and the time constant of the fall in isovolumic left ventricular pressure did not differ between the groups. In conclusion, L-NAME attenuates hypotension, but does not improve cardiac depression in anaphylaxis in dogs. Our finding that NOS inhibitor did not improve cardiac function implies that the production of NO in anaphylaxis may have a protective effect with regard to cardiac performance.

[Effect of horizontal lithotomy position on spread of hyperbaric dibucaine spinal anesthesia]

We have studied the effect of horizontal lithotomy position on the spread of hyperbaric dibucaine spinal anesthesia. In three groups of 20 patients, 7.2 mg of hyperbaric dibucaine was injected intrathecally in the lateral decubitus position. In group supine, the patients were kept in supine horizontal position in which patient's legs and thighs were extended throughout the operation. In group lithotomy A, immediately after the spinal injection, the patients were placed into the lithotomy position. In group lithotomy B, after the spinal injection, the patients were placed immediately in the supine horizontal position for 15 min and then placed into the lithotomy position. There were no significant differences in height of sensory blockade among the three groups. The lithotomy position did not significantly affect the level of sensory blockade with hyperbaric dibucaine.

[Continuous monitoring of arterial blood oxygen saturation with a pulse oximeter during spinal anesthesia]

The arterial oxygen saturation was continuously monitored in 50 patients under spinal anesthesia. Of the 50 patients, low oxygen saturation below 95% and/or its decrease of more than 5% was observed in 19 patients (38%). The remaining 31 patients (62%) showed a normal oxygen saturation. Pentazocine 0.5 mg.kg-1 i.v. correlated significantly with arterial oxygen desaturation (P = 0.0001). It is possible that laparotomy is associated with the desaturation (P = 0.0582). No correlation between desaturation and the other factors (level of analgesia, position during operation, and hydroxyzine premedication) was found.

[Rectal diclofenac coupled with continuous epidural infusion with buprenorphine and bupivacaine for pain relief after upper and lower abdominal surgery]

This investigation was conducted to determine the analgesic efficacy of rectal diclofenac coupled with continuous epidural infusion with buprenorphine and bupivacaine for pain relief after upper and lower abdominal surgery. Forty patients in control group received epidural buprenorphine 0.1 mg in 8 ml of 0.25% bupivacaine immediately after surgery and subsequently infusion was started with the solution of epidural buprenorphine 15 micrograms in 1 ml of 0.23% bupivacaine at a rate of 1 ml.h-1 for 48 h. Forty patients in study group received rectal diclofenac 50 mg immediately after surgery in addition to the same epidural injection method described above. Adding rectal diclofenac to continuous epidural infusion of buprenorphine and bupivacaine produced enhanced analgesia and reduced pain scores measured by VAS after upper abdominal surgery. However, after lower abdominal surgery, such effects of rectal diclofenac obtained after upper abdominal surgery were not demonstrable.

Infrared angiography of the anterior ocular segment

We performed angiography with indocyanine green (ICG) and fluorescein using a scanning laser ophthalmoscope (SLO) in the anterior segments of seven normal and 35 diseased eyes. ICG angiography revealed the radical stromal vessels and minor arterial circle in brown irides, which were not detected by fluorescein angiography. High penetration of infrared fluorescence through the pigmented tissue and absence of extravasation of ICG facilitated demonstration of the fine structure of iris rubeosis and its origins from stromal vessels. In 11 diabetic eyes, the iris rubeosis showed three basic patterns of location: along the pupillary margin; originating from the iris root; and arising from stromal radial vessels near the collarette. ICG gonioangiography with SLO showed fine structure of angle rubeosis because of its high resolution and greater depth in focus. Rubeotic vessels in the chamber angle were perfused by neovascular trunks which arose from the iris root in all 12 rubeotic eyes. Rubeosis in the iris and the angle consistently showed no extravasation of the ICG dye, while fluorescein quickly leaked out. ICG angiography with SLO in the anterior ocular segment proved to be a useful means to study the structure and the hemodynamics of normal and newly formed vessels.

[Spinal anesthesia for oophorectomy in a patient with pulmonary lymphangiomyomatosis accompanied by hypochondriasis]

A 41-year-old woman with pulmonary lymphangiomyomatosis had been scheduled for bilateral oophorectomy which led to amelioration of the pulmonary pathology. The discrepancy between her dyspnea on exertion and lung function tests suggested that she had a marked tendency toward hypochondria. Therefore, we chose spinal anesthesia because of its technical simplicity, rapid onset, and effectiveness of some sedatives used perioperatively. Surgery was performed uneventfully. The anesthetic method mentioned above did not worsen respiratory function perioperatively. Spinal anesthesia is thought to be appropriate anesthesia for patients with pulmonary lymphangiomyomatosis, if feasible.

[Postoperative analgesia service by continuous epidural infusion with buprenorphine]

We examined the analgesic efficacy and side effects of continuous epidural infusion with buprenorphine in 340 surgical patients. The patients received epidural injection of 0.1 mg of buprenorphine in 8 ml of 0.25% bupivacaine immediately after surgery. The patients who underwent thoracotomy or intraabdominal surgery were subsequently infused with buprenorphine 15 micrograms in 1 ml of 0.25% buprenorphine at a rate of 1 ml.h-1 for 48 h. In the other kinds of surgery, patients were infused with buprenorphine 8 micrograms in 1 ml of 0.25% buprenorphine at a rate of 1 ml.h-1 for 48 h. The patients who did not need additional narcotics were 68% and 83% on the postoperative day 1 and 2, respectively. Visual analogue scale (VAS) was 22 +/- 2 mm at rest and 43 +/- 2 mm at movement on the postoperative day 1. Corresponding values on the postoperative day 2 were 16 +/- 2 mm and 37 +/- 2 mm, respectively. Nausea and vomiting were found in 12.4% of the patients.

Spread of subarachnoid hyperbaric amethocaine in pregnant women

In order to examine how the gestational period influences the spread of spinal anaesthesia, we have measured the extent of spinal block produced by hyperbaric amethocaine 8 mg in 90 women. The patients were allocated to one of five groups according to the gestational period: non-pregnant group (n = 17), first trimester group (6-12 weeks, n = 14), second trimester group (13-24 weeks, n = 26), third trimester group (25-36 weeks, n = 15) and term group (37-41 weeks, n = 18). Maximum cephalad spread of analgesia was significantly higher in the second trimester (median T3 (range T9-C6)), third trimester (T3 (T4-C7)) and term groups (T2.5 (T4-C8)) than in the nonpregnant (T4 (T8-T2)) and first trimester groups (T4 (T11-C7)). We found that not only term pregnancy but also second and third trimester pregnancies enhanced the spread of spinal anaesthesia, and that first trimester pregnancy did not affect the spread of spinal anaesthesia.

[Continuous epidural buprenorphine for postoperative pain relief after thoracotomy]

To evaluate postoperative analgesia and side effects of epidural buprenorphine, 60 patients after thoracotomy were divided into 6 groups. All patients received a bolus epidural administration of buprenorphine 0.1 mg in 8 ml of 0.25% bupivacaine. Following this epidural bolus, 10 patients in each group were given 0.25% bupivacaine alone (group A), buprenorphine 5 micrograms in 1 ml of 0.25% bupivacaine (group B), buprenorphine 8 micrograms in 1 ml of 0.25% bupivacaine (group C), buprenorphine 12 micrograms in 1 ml of 0.25% bupivacaine (group D), buprenorphine 15 micrograms in 1 ml of 0.25% bupivacaine (group E) or buprenorphine 18 micrograms in 1 ml of 0.25% bupivacaine (group F) with a portable disposable device at a rate of 1 ml.h-1 for 48 h. The percentages of patients who did not need additional narcotics for the first 24 hours postoperatively in group A, B, C, D, E, and F were 20%, 40%, 30%, 50%, 60%, and 70%, respectively. Those for the second 24 hours postoperatively in each group were 40%, 50%, 70%, 60%, 90%, and 90%, respectively. No significant difference in the incidence of side-effect was found among 6 groups. We concluded that optimal epidural doses of buprenorphine for post-thoracotomy pain relief are 15 and 18 micrograms.h-1 in the first and second 24 hours postoperatively, respectively.

[Reevaluation of hypothermia as protective measures against cerebral ischemia]

Two patients underwent carotid artery ligation for the purpose of surgical hemostasis either under hypothermia or under normothermia. One was 56-year-old man with rupture of brachiocephalic artery following esophagectomy. The bilateral common carotid arteries were ligated for bypass-grafting between the right internal carotid artery and the left common carotid artery for 35 min under surface-induced hypothermia at a rectal temperature of 30.7 degrees C. No postoperative neurological deficit developed. The other was 40-year-old woman with a malignant parotid tumor involving left internal carotid artery. The left carotid artery was ligated for 20 min at a rectal temperature of 37.3 degrees C. Cerebral ischemia developed postoperatively. Mild to moderate hypothermia should be reevaluated as one of useful measures to protect the brain from cerebral ischemia.

[Psychological evaluation of out-patients in our pain clinic using self-rating depression scale and state-trate anxiety inventory questionnaire]

In 98 out-patients who visited our pain clinic, we evaluated their psychological status before the first examination and one month after the treatment, using self-rating depression scale (SDS) and state-trate anxiety inventory (STAI). SDS, state anxiety, and trate anxiety scores were significantly higher in the patients with pain (trigeminal neuralgia, neck-shoulder-arm pain syndrome, lumbago and psychological pain, n = 55) compared with the patients without pain (sudden deafness and facial nerve palsy, n = 43) (P < 0.01, 0.05, 0.01). Of the patients with pain, patients with psychogenic pain showed the highest score in every test. The scores of SDS and state anxiety became significantly lower one month after the treatments compared with ones before the first examination (P < 0.01). It was considered that the decline in every score was due to the treatments in our pain clinic. In patients whose score of trate anxiety before the first examination was more than 50 points, the SDS and state anxiety showed high scores even one month after the treatments. This finding suggests that these patients need psychosomatic managements.

[Diagnosis of accidental subdural block]

Accidental subdural block occurred in a 47-year-old man who underwent gastrectomy under nitrous oxide-sevoflurane anesthesia combined with continuous epidural block. The development of subdural block was suspected from unexpectedly severe hypotension with small doses of mepivacaine during operation and was confirmed by a characteristic X-ray photograph after operation. The subdural block should be suspected from abnormal changes in vital signs and by careful observation of X-ray photographs, because it is not always easy to determine the presence of contrast media either in the subdural space or in the epidural space.

[Patient's complaints preceding severe bradycardia and hypotension during spinal anesthesia]

We reported an episode of sudden bradycardia and hypotension during spinal anesthesia, in which the patient complained of nausea before the bradycardia and hypotension were recognized by the monitors, such as, intermittent measurement of arterial pressure, electrocardiography, pulse oxymetry and continuous arterial blood gas analysis. We emphasize the importance of strict vigilance during spinal anesthesia.

[Lumbar epidurography with iohexol: the effect of aging on the leakage of contrast media from the intervertebral foramina]

The lateral and longitudinal spread of contrast media was investigated by lumbar epidurography with 8 ml of iohexol in 47 patients aged 25 yr to 86 yr. Iohexol was injected through the epidural catheter epidurally advanced by 5 cm cephalad from the L 1-4 interspace. A significant correlation was found between the longitudinal spread of iohexol and aging. No correlation was found between the leakage of iohexol from the intervertebral foramina and aging. This finding may deny the hypothesis that in elderly patients, the more extensive longitudinal spread of local anesthetics in the epidural space may be caused by its smaller leakage from the intervertebral foramina.

[A radiological analysis of the position of lumbar epidural catheters: a comparison between median and paramedian approach]

The position of lumbar epidural catheters was confirmed by radiography in 71 patients. Catheters were advanced by 5 cm cephalad in the lumbar epidural space by paramedian approach (Group P: n = 28) or median one (Group M: n = 43) and contrast media was injected through the catheters. If the contrast media was present in the paravertebral regions, the catheter was considered to be in the abnormal position. The incidence of the abnormal position of the catheters was higher in group M than in group P significantly. To advance an epidural catheter longer into the lumbar epidural space, paramedian approach may be superior to median one.

Spread of subarachnoid hyperbaric amethocaine in adolescents

We have compared the spread of subarachnoid hyperbaric amethocaine in adolescents with that in adults. Amethocaine 8 mg in 2 ml of 10% glucose was injected through a 25-gauge spinal needle inserted at the L3-4 interspace in 21 adolescents aged 12-16 yr and in 111 adults aged 17-82 yr. Although we found no differences in height, weight or body mass index between the adolescents and adults, maximum spread of analgesia was significantly higher in the adolescents (median T3 (range T4-C5) than in the adults (T4 (T9-C7)). We conclude that subarachnoid injection of hyperbaric amethocaine produces an unexpectedly higher level of analgesia in adolescents than in adults.

[Severe bradycardia and hypotension during epidural anesthesia in a patient undergoing hemorrhoidectomy]

Severe bradycardia and hypotension developed suddenly in two patients undergoing hemorrhoidectomy under lumbar epidural anesthesia in the jackknife position, about 5 to 10 min after epidural administration of buprenorphine. Severe vago-vagal reflex was supposed to have been induced with buprenorphine in a situation where venous return was decreased by epidural anesthesia and the jackknife position.

Methylmethacrylate bone cement does not release histamine in patients undergoing prosthetic replacement of the femoral head

This study was designed to see if methylmethacrylate monomer bone cement released histamine in 13 patients undergoing total hip replacement surgery with a cemented prosthesis, compared with seven control patients receiving a cementless porous-coated prosthesis. Blood samples for plasma concentrations of histamine were obtained before the start of anaesthesia, immediately before insertion of methylmethacrylate bone cement into the shaft of the femur in the cemented fixation group or before insertion of the femoral component of the prosthesis in the cementless fixation group, and 15, 30 and 60 min after the start of implantation of the prosthesis. In both groups, changes in plasma histamine did not differ significantly from baseline before implantation of cement. There were no significant differences between groups. We conclude that methylmethacrylate bone cement does not release histamine during total hip replacement surgery.

Principal component analysis, using the measurements during running and swimming test, in thoroughbred horses

To investigate whether the running exercise fitness of individual horses could be assessed by a standardized swimming exercise test, the results of multivariate analysis of the exercise parameters measured during incremental running and swimming tests were compared. Ten thoroughbred horses were subjected to different types of exercise tests on a track or in a pool, and the maximum heart rate during and the blood lactate concentration immediately after the exercise were examined. Serial exercise parameters (VLA2, VLA4, LA0, V150, V200, HRS, HRLA2, HRLA4) referred to as the indices related to the adaptation of cardiovascular or metabolic systems were computed using the relationships between these measurements and velocity during each test, and were analyzed by a multivariate procedure, i.e. the principal component analysis. The correlation diagram between the exercise parameters on the first two component axes in running were similar to that in swimming. When the exercise fitness in each horse was compared between running and swimming, three horses trained by short-term endurance exercise were statistically distinguished in both tests and differed as a group from the other horses. Therefore, it is thought that evaluation of the exercise fitness in swimming using the multivariate analysis is useful for predicting poor performing horses on a track.

[Effects of intravenous and intramuscular atropine on bradycardia during spinal anesthesia]

The effects of intravenous and intramuscular atropine on pulse rate have been studied in 40 patients undergoing gynecological surgery. Intramuscular atropine 0.5 mg was administered 30 min before induction of spinal anesthesia in 20 patients (i.m. group). Intravenous atropine 0.5 mg was administered immediately after induction of spinal anesthesia in 20 patients (i.v. group). Decrease in heart rate after spinal block was significantly less in i.v. group than in i.m. group. Although no one in i.v. group was given an additional atropine, 10% of the patients in i.m. group was given an additional atropine for bradycardia. Authors conclude that intravenous atropine has more significant effect on prevention of bradycardia during spinal anesthesia compared with intramuscular atropine.

Production of nitric oxide in anaphylaxis in rabbits

To verify production of nitric oxide (NO) in anaphylaxis, we measured NO in peripheral tissue in anaphylactic rabbits using an NO-sensitive electrode. Rabbits were sensitized to horse serum, which was later administered over 10 s into the systemic circulation to induce anaphylaxis. Blood pressure (BP), central venous pressure (CVP), heart rate, and NO were recorded continuously for 80 min after antigen challenge. The NO-sensitive electrode was placed between the superficial abdominal fascia and the rectus abdominis fascia. The NO concentration increased to 3000-4800 pA (about 3-4.8 microM NO) within 4 min after initiation of anaphylaxis, at which time BP was decreased and CVP increased; however, NO production was continuously observed 30-60 min after antigen challenge, during which time changes in BP and CVP were not correlated with changes in NO concentration. In conclusion, NO production can be detected using an NO-selective electrode in anaphylactic rabbits.

Sevoflurane and isoflurane protect against bronchospasm in dogs

BACKGROUND

Halothane and isoflurane have been shown to be effective in reversing bronchoconstriction; however, the effects of sevoflurane have not been well defined. We studied whether sevoflurane, compared with isoflurane, attenuates bronchospasm in dogs.

METHODS

Twenty-four dogs sensitized to Ascaris suum were assigned to three groups: control (n = 8), sevoflurane (n = 8), or isoflurane (n = 8). In all dogs, anesthesia was induced with pentobarbital. In the sevoflurane and isoflurane groups, the volatile anesthetics were administered at an end-tidal anesthetic concentration of 1 MAC throughout the study. After measurement of pulmonary resistance (RL) and dynamic pulmonary compliance (Cdyn) at baseline, A. suum antigen was administered intravenously into the systemic circulation to induce anaphylaxis, and RL and Cdyn were recorded continuously for 120 min after antigen challenge.

RESULTS

Effects on RL and Cdyn were maximal 5 min after the start of systemic administration of antigen in all groups. Both 1 MAC sevoflurane and 1 MAC isoflurane significantly attenuated the increase in RL provoked by antigen challenge, but the attenuation from 10 to 15 min after challenge in the sevoflurane group was not significantly different from that in the control group. There was no significant difference in RL between sevoflurane and isoflurane. For both sevoflurane and isoflurane, attenuation of the decrease in Cdyn was not statistically significant. There was no significant difference in Cdyn between sevoflurane and isoflurane.

CONCLUSIONS

Sevoflurane is as effective as isoflurane in attenuating bronchoconstriction associated with anaphylaxis in dogs. Sevoflurane may be a useful alternative to halothane, enflurane, or isoflurane in the treatment of bronchospasm in asthma or anaphylaxis.