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Biomedical subjects

M Miyabe

Publications and source records attributed to M Miyabe.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effect of plasma alpha1-acid glycoprotein concentration on the accumulation of lidocaine metabolites during continuous epidural anesthesia in infants and children.

OBJECTIVE: Alpha1-acid glycoprotein (AAG) is an acute-phase protein that is responsible for binding basic drugs such as lidocaine (LDC). The effect of AAG on the duration of LDC during continuous epidural anesthesia in infants and young children was investigated. PATIENTS, MATERIALS AND METHODS: Plasma levels of LDC and its active metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), were monitored in 20 infants and children, 5 months to 6 years of age, who received continuous epidural infusion of 2.5 mg kg(-1) LDC hourly during abdominal or thoracic surgeries. RESULTS: Plasma LDC concentrations were constant after the first hour of injection. In contrast, the concentrations of MEGX and GX increased continuously during epidural infusion in all patients. The plasma AAG concentration correlated significantly (r = 0.814, p<0.001) with the steady-state LDC level. In addition, significant inverse correlation was observed between the plasma AAG concentration and the accumulation rate of MEGX (r = 0.742, p = 0.002). The plasma AAG concentration and the accumulation rate of GX correlated weakly (r = 0.474, p = 0.035). There was no correlation between the age of the patient and the plasma AAG concentrations (r = 0.295, p = 0.206). CONCLUSION: Our results suggest that the plasma AAG concentration is a valuable index in preventing the toxicity caused by accumulation of MEGX during continuous epidural anesthesia of LDC.

Anesthesia, Epidural↗
PubMed1999

[Epidural anesthesia for cesarean section in a patient with dilated cardiomyopathy (DCM)].

A 23-year-old patient with dilated cardio myopathy (DCM) was scheduled for a cesarean section. We inserted an epidural catheter at the L 2/3 interspace and injected 1.5% lidocaine 6 ml with epinephrine 30 micro g and fentanyl 50 micro g. The analgesic level 15 minutes after injection was achieved up to the eighth thoracic dermatome. Dopamin 5 micro g.kg-1.min-1 was infused simultaneously. Analgesia was sufficient for the surgery, and heart rate and blood pressure were stable throughout the operation. The infant's apgar scores were 9 and 10. Epidural anesthesia is one of the options for cesarean section in pregnant women with DCM.

Adult↗
PubMed1998

Thoracic epidural block attenuates cardiovascular response to apnea in rabbits.

PURPOSE: Apnea is one of the potential complications during anaesthesia. If sympathetic nerve activity is blocked by epidural anaesthesia, circulatory responses to apnea might change. Our objective was to assess the potential modifying effects of epidural anaesthesia on the cardiovascular responses to apnea in the animals. METHODS: Twenty rabbits anaesthetised with pentobarbital (25 mg.kg-1 i.v., 8 mg.kg-1.hr-1) and pacuronium bromide (0.2 mg.kg-1.hr-1 i.v.) were randomly assigned to one of two groups: control (n = 10) and epidural (n = 10). In the control group, 0.6 ml saline, and in the epidural group, 0.6 ml lidocaine 1% was injected into the epidural space respectively. After mechanical ventilation with FIO2 0.4, apnea was induced by disconnecting the anaesthetic circuit from the endotracheal tube, and mean arterial pressure (MAP), heart rate (HR), and time to cardiac arrest were measured. RESULTS: Before apnea MAP was lower in the epidural than in the control group (73 +/- 10 vs 91 +/- 10 mmHg, P < 0.05). Heart rate was not different between groups (264 +/- 36 vs 266 +/- 24 bpm). Mean arterial pressure increased in the control group after apnea, but not in the epidural group. The time to cardiac arrest was less in the epidural group than in the control group (420 +/- 67 vs 520 +/- 61 sec, P < 0.05). Heart rate decreased markedly after apnea in the control group whereas it decreased gradually in the epidural group. CONCLUSION: Thoracic epidural anaesthesia attenuated cardiovascular response to apnea and reduced the time to cardiac arrest.

Anesthesia, Epidural↗
PubMed1998

Nitric oxide in the liver may not be involved in blood redistribution during hemorrhagic shock in the dog.

We previously reported that nitric oxide (NO) in the brain cortex increases during hemorrhagic shock (HS) and then recovers to a baseline level by a retransfusion. Accordingly, we suggested that NO may play a role in blood redistribution during HS. To ascertain whether or not NO contributes to blood redistribution, we have investigated the changes in the liver's NO production during HS. Mongrel dogs were used in the study. After each dog was anesthetized with pentobarbital, an NO-selective electrode was placed in its liver, and a probe to measure hepatic blood flow (HF) was placed on the liver's surface. HS was induced until a mean arterial blood pressure of <40 mmHg was reached. In Group I (n=5), HS was maintained for 30 min. In Group II (n=7), shed blood was reinfused at 10 min after HS. In Group III (n=7), 10 min after NG-nitro-L-arginine methyl ester 30 mg/kg intravenously (i.v.), the same procedures were performed as in Group II. In Groups II and III, although 10 min of HS produced an increase in NO-related electrical current [Group II, 2,197+/-786 pA; Group III, 983+/-77 pA (mean+/-standard error)], reinfusion of shed blood restored the NO-related electrical current to its baseline value. HF in Groups I and II decreased continuously during HS, and it recovered to baseline after the restoration from HS in Group II. In Group III, NG-nitro-L-arginine methyl ester 30 mg/kg i.v. decreased HF 12.7+/-.7 to 10.2+/-.6 mL/min/100 g (mean+/-standard error, p < .05). In conclusion, although NO produced in the liver might play an important pathophysiologic role in HS, it may not affect the blood redistribution during HS, such as in mean arterial blood pressure <40 mmHg.

Animals↗
PubMed1997

Comparative analysis of brain protection by N-methyl-D-aspartate receptor antagonists after transient focal ischemia in cats.

OBJECTIVE: We tested the hypothesis that the administration of the competitive N-methyl-D-aspartate (NMDA) receptor antagonist 2R,4R,5S-(2-amino-4,5-(1,2-cyclohexyl)-7-phosphonoheptanoic acid) (NPC 17742) or cis-4-(phosphonomethyl) piperidine-2-carboxylic acid (CGS 19755) or the noncompetitive NMDA receptor antagonist dizocilpine (MK-801), at the appropriate doses, would all have efficacy in decreasing early postischemic brain injury in a feline model of transient focal ischemia. DESIGN: Prospective, randomized, controlled animal trial. SETTING: University research laboratory. SUBJECTS: Forty mixed-breed cats. INTERVENTIONS: Halothane-anesthetized cats underwent 90 mins of left middle cerebral artery occlusion plus 4 hrs of reperfusion. At 75 mins of ischemia, control cats received intravenous saline (n = 10). Experimental cats (n = 10 in each group) were treated with NPC 17742 (5 mg/kg bolus and 2.5 mg/kg/hr throughout reperfusion), MK-801 (5 mg/kg intravenous bolus), or CGS 19755 (40 mg/kg intravenous bolus) in a randomized fashion. MEASUREMENTS AND MAIN RESULTS: Microsphere-determined blood flow to the ipsilateral inferior temporal cortex and caudate nucleus decreased to the same extent during ischemia, and recovered to the same extent during early reperfusion, in the four groups. Triphenyltetrazolium-determined injury volume of the ipsilateral caudate nucleus in cats treated with NPC 17742 (105 +/- 25 [SEM] mm3), MK-801 (97 +/- 22 mm3), and CGS 19755 (97 +/- 13 mm3) was less than in control cats (198 +/- 21 mm3). Hemisphere injury volumes with NPC 17742 (1209 +/- 405 mm3) and MK-801 (1338 +/- 395 mm3) were less than that value in controls (2193 +/- 372 mm3), whereas injury volume with CGS 19755 (1553 +/- 519 mm3) treatment did not attain significance (p < .09). CONCLUSIONS: NMDA receptor activation during reperfusion may contribute to the progression of injury in ischemic border regions after 90 mins of transient focal ischemia in the cat. At the doses chosen, there appear to be no major differences in therapeutic efficacy for competitive and noncompetitive NMDA receptor antagonists.

Amino Acids↗
PubMed1997

Nitric oxide in the brain increases during a short period of hemorrhagic shock in the rabbit.

We investigated the changes in nitric oxide (NO) concentration in the brain of the rabbit by measuring NO-related electrical current. Seventeen Japanese white rabbits were anesthetized with pentobarbital sodium and mechanically ventilated with tracheotomy tubes. An NO-selective electrode was used for the detection of NO. After a round craniotomy in the left parietal lobe, an NO-sensitive electrode was placed in the brain. Rabbits were hemorrhaged to a mean arterial blood pressure of 35 +/- 7 mmHg, from a baseline of 112 +/- 12 mmHg (mean +/- SD). The shock was maintained for 5 min. The mean extracted blood volume was 77 +/- 17 mL. Then, retransfusion of shed blood caused a rapid restoration of mean arterial blood pressure. The amount of time required to induce hemorrhagic shock was 261 +/- 34 s. The time required to retransfuse the extracted blood was 233 +/- 43 s (p > .05). During shock, the NO-selective electrode produced an extensive increase in current, from 110 +/- 94.5 pA to 1010 +/- 543 pA (mean +/- SD, p < .001). The current continued to increase for a few minutes after the recovery from shock, with a maximal increase reaching 1245 +/- 515 pA (p < .001). This enhanced release of NO-related current (1,132%) recovered to the baseline level at 44 +/- 7 min after retransfusion. When the same investigation was performed on the same animals on which had been placed the same electrode pretreated with NG-nitro-L-arginine methylester (L-NAME) 30 mg/kg intravenously, NO-related current increased from 101 +/- 158 to a maximum of 860 +/- 406 pA (752%). Our results suggest that NO may play an important role in the brain during the early period of hemorrhagic shock, and that L-NAME 30 mg/kg intravenously might not inhibit the NO production in the parietal lobe, probably due to a blood-brain barrier to the nitric oxide synthase-inhibiting drug.

Animals↗
PubMed1997

[Pre- and post-operative management of cesarean section in a parturient with severe preeclampsia accompanied by hyperdynamic state].

A 37-year-old parturient with severe preeclampsia accompanied by pulmonary edema underwent emergency cesarean section. Pulmonary artery (PA) catheter inserted while the patient was awake revealed hyperdynamic state with increased cardiac index and preload, and decreased systemic vascular resistance. Epidural anesthesia and analgesia were provided with a satisfactory outcome. Monitoring of PA pressure and cardiac index was continued postoperatively in ICU for fluid management. We conclude that preoperative PA catheterization provides useful hemodynamic information in severe preeclamptic patients associated with persistent oliguria, pulmonary edema and hyperdynamic state.

Adult↗
PubMed1996

Comparison of the Jackson-Rees circuit, the pediatric circle, and the MERA F breathing system for pediatric anesthesia.

The purpose of this study was to compare the Jackson-Rees circuit with the pediatric circle and MERA F breathing system (MERA F system) for pediatric anesthesia from the viewpoint of work of breathing (WOB). Twenty-three children (2-10 yr old) were studied during spontaneous breathing under endotracheal anesthesia with 4 L/min nitrous oxide, 2 L/min oxygen, and 1% end-tidal concentration of sevoflurane. WOB, inspiratory and expiratory airway resistance, dynamic compliance (CDYN), pressure time product (PTP), and arterial blood gasses were measured in the three circuits. The inspiratory WOB was estimated directly by measuring the esophageal pressure-volume loop using the Campbell technique. In a laboratory study, we measured the compliances of the Jackson-Rees circuit, the pediatric circle, the MERA F system, and the adult circuit. WOB differed among the three circuits (MERA F system > pediatric circle > Jackson-Rees circuit). Inspiratory and expiratory resistances, and arterial carbon dioxide tension in the Jackson-Rees circuit were significantly lower than those of both the pediatric circle and MERA F system. The CDYN and PTP in the MERA F system were significantly higher than those in both the Jackson-Rees circuit and the pediatric circle. The MERA F system had significantly higher compliance than the Jackson-Rees circuit and pediatric circle. It is concluded that the Jackson-Rees circuit is most efficient, the pediatric circle is intermediate, and the MERA F system is the least efficient from the viewpoint of WOB during spontaneous breathing for pediatric anesthesia.

Airway Resistance↗
PubMed1996

Correlation of the average water diffusion constant with cerebral blood flow and ischemic damage after transient middle cerebral artery occlusion in cats.

Magnetic resonance water diffusion imaging can detect early ischemic changes in stroke. Using a middle cerebral artery occlusion model, we examined which range of values of the orientation-independent diffusion quantity Dav = 1/3Trace(D) = 1/3(Dxx + Dyy + Dzz) is an early noninvasive indicator of reduced cerebral perfusion and focal brain injury. Cats underwent either a 30-min occlusion followed by 3.5 h reperfusion (n = 7) or a 60-min occlusion followed by 4-h reperfusion (n = 6). Repeated measurements of CBF were made with radiolabeled microspheres, and acute focal injury was measured with triphenyltetrazolium chloride (TTC) staining. During occlusion, the decrease in Dav correlated with CBF for caudate [30-min occlusion (n = 13): p < 0.0001: 60-min occlusion (n = 6): p < 0.02] and for cortex [30-min occlusion (n = 12): p < 0.0001: 60-min occlusion (n = 5): p < 0.04]. Variable caudate and hemispheric injury levels were found among cats in both groups. The area of tissue injury demarcated by TTC began to correlate with the area of reduced Dav by 30 min of occlusion (p < 0.02), and this correlation improved (p < 0.0001) at 1, 1.5, and 2.0 h after the onset of occlusion. The time necessary to reach a one-to-one correspondence between the percent of hemisphere injured and the percent of hemispheric area with Dav < 0.65 x 10(-9) m2/s was 2 h after occlusion. Thus, the absolute value of Dav is a good indicator of the risk of tissue injury, whereas the combination of Dav and the length of time of Dav reduction is an excellent predictor of acute focal tissue injury demarcated by TTC staining.

Animals↗
PubMed1995

Acute pulmonary edema associated with transfusion of packed red blood cells.

We experienced a patient who suffered noncardiogenic acute pulmonary edema after transfusion of packed red blood cells which contained antigranulocyte antibodies. The data suggested that complement activation and the release of polymorphonuclear protease were involved in the pathogenesis of the complication in the present patient. Furthermore, blood coagulative system was also activated after the transfusion. The underlying mechanisms of the complication are discussed.

Acute Disease↗
PubMed1995

The effect of lithotomy position on arterial blood pressure after spinal anesthesia.

We compared the effect of the lithotomy position on the systolic blood pressure (SBP) with the horizontal position after spinal block. The lithotomy position was performed 5 min after spinal block. The change in SBP was expressed as percent of depression from the baseline value. The SBP increased by the lithotomy position (n = 14) from a 16% decrease to an 8% decrease. On the contrary, in the horizontal group (n = 14), SBP decreased 16% at 5 min and continued to decrease to 21%. The extent of the cephalad spread of analgesia 20 min after spinal block was same between the two groups (T-5 +/- 2 vs T-5 +/- 2, respectively). From these results we conclude that the lithotomy position after spinal anesthesia attenuates the decrease in arterial blood pressure and does not affect the cephalad spread of analgesia.

Adult↗
PubMed1995

Blood coagulation and fibrinolytic activity during femoral neck prosthetic replacement using bone cement.

To assess the blood coagulative and fibrinolytic responses during cemented femoral neck replacement, we measured these parameters in 9 patients, including anti-thrombin III (AT-III), prothrombin time (PT) and activated partial thromboplastin time (APTT) before surgery, just before packing bone cement and after the insertion of the prosthesis. We also measured thrombin-anti-thrombin III complex (TAT), plasmin-alpha 2-plasmin inhibitor complex (PIC), and D-dimer. A significant increase in APTT, and decrease in AT-III and PT were observed before the insertion of bone cement and prosthesis. The value of TAT and D-dimer increased significantly after the insertion of the prosthesis, but there were no significant changes in PIC. The data suggest that blood coagulation is activated after the insertion of bone cement and prosthesis into the femoral shaft, and in addition, the fibrinolysis is also accelerated secondary to the activation of the coagulation. Further investigations are needed to establish whether the activation of the coagulation induced by the cemented replacement exerts a great influence on the appearance of pulmonary thrombosis or circulatory depression.

Adult↗
PubMed1995

[Comparison of intubating condition under sevoflurane and halothane anesthesia in pediatric patients].

We compared intubating conditions under sevoflurane (group S) and halothane (group H) anesthesia in pediatric patients for otorhinolaryngological surgery. One hundred and six patients were divided randomly into group S (n = 60) and group H (n = 46). Anesthesia was induced with nitrous oxide-oxygen-sevoflurane (GOS, end-tidal sevoflurane concentration; 4.5%) or nitrous oxide-oxygen-halothane (GOF, end-tidal halothane concentration; 1.6%). Intubating conditions were assessed according to the intubation score, which consists of the following three factors; mouth opening, visibility of vocal cord and body movement. Each factor is divided into three grades (0, 1, 2); total scores of 0 correspond to excellent. In comparing the groups with respect to anesthetic induction, group S required 180 sec for disappearance of spontaneous breathing and 660 sec for completion of intubation, while, in group H, the above time intervals were 188 and 676 sec, respectively. We achieved significantly better intubating conditions in group H than group S. There were significantly more cases in group S than in group H in which vocal cord visibility was insufficient. Body movement during intubation was observed in 27% and 26% of patients in group S and H, respectively. In conclusion, halothane anesthesia provides better intubating conditions than sevoflurane anesthesia in slow induction for pediatric patients.

Anesthesia, Inhalation↗
PubMed1995

[Hemodynamic and blood gas changes during femoral neck prosthetic replacement using a cement gun].

We investigated hemodynamic and blood gas changes in eight patients undergoing femoral neck prosthetic replacement. We measured blood pressure, heart rate, pulmonary artery pressure, cardiac output and blood gas before packing bone cement with a cement gun and 5, 10, and 15 min after the insertion of the prosthesis. Significant increases in mean pulmonary artery pressure, and arterial PCO2 were observed, but there were no significant changes in mean arterial pressure, cardiac output, or arterial PaO2. These pulmonary circulatory and blood gas alterations suggested that pulmonary embolism or pulmonary vasospasm had been brought about by the insertion of the prosthesis, but this did not result in systemic changes in the patients in this study. In conclusion, it is recommended to monitor circulatory and respiratory changes closely to detect pulmonary embolism during femoral neck prosthetic replacement using a cement gun.

Aged↗
PubMed1995

[Effect of preoperative treatment with recombinant human erythropoietin in patients undergoing hemodilutional autologous transfusion].

This study evaluated whether a combination of recombinant human erythropoietin (rHuEPO) and hemodilutional autologous transfusion could reduce homologous blood transfusion in 37 patients who underwent elective urological surgery. A single dose of 6000 IU rHuEPO was administered 2 weeks before operation to patients whose preoperative hemoglobin was less than 12.0 g.dl-1 (8.5-12.0 g.dl-1) (EPO group, n = 15) and compared these with control subjects whose preoperative hemoglobin was more than 12.0 g.dl-1 (non-EPO group, n = 22). Both hemoglobin and hematocrit levels after administration of rHuEPO in the EPO group increased significantly to the same levels as in those in the non-EPO group and remained at these levels. The mean volume of donated autologous blood was 980 g in the EPO group and 110 g in the non-EPO group. The mean surgical blood loss was 1330 g in the EPO group and 1120 g in the non-EPO group. No homologous blood transfusion was required in 80 percent of the cases in both groups: however, homologous transfusions were added to 3 cases in the EPO group and 4 cases in the non-EPO group whose surgical blood loss was over 2500 g. We conclude that the combination of preoperative rHuEPO treatment and hemodilutional autologous transfusion can reduce homologous transfusion during surgery in anemic patients.

Aged↗