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Biomedical subjects

M Kawamata

Publications and source records attributed to M Kawamata.

At least 73 records · Page 4Linked to original sources
PubMed1992

[An unusual cause of anesthetic ventilator malfunction].

We report a case of malfunction of an anesthetic ventilator by an unusual cause. A 48-year-old male with gastric cancer was scheduled for gastrectomy. Anesthesia was maintained with enflurane, N2O, O2 and epidural blockade using a semiclosed circuit system. The patient was ventilated using AV1 anesthetic machine (Dräger Co.). Forty minutes after induction of anesthesia, chest movement of the patient suddenly stopped. There was no gas flow to the patient during inspiratory phase. Air leak was not found in anesthetic respiratory circuit and at the bellows of the ventilator. The supply of oxygen and air to the anesthetic machine was sufficient. Since we could not find any cause of the ventilator failure, anesthesia was maintained with manual ventilation by using another anesthetic machine until completion of the surgery. After the surgery, we recognized that the controller unit of expiratory valve of the ventilator was obstructed by a Tamper Proof Film, which seals the outlet of a commercial bag of lactated Ringer's solution (Solulact, Terumo Co.). It seems that the film dropped accidentally between the main part and the ventilator system of anesthetic machine when the bellows was exchanged before the surgery, and moved on to the controller unit of the expiratory valve of the ventilatory system during surgery. In conclusion, it is necessary for anesthetists to understand the inner structure and system of the anesthetic machine and to check the anesthetic machine to avoid the troubles and accidents related to anesthetic machine.

Anesthesia, Closed-Circuit↗
PubMed1992

[Effects of induced hypotensive anesthesia on the blood coagulation-fibrinolysis system measured by thrombelastography--comparison between prostaglandin E1 and trimethaphan].

The coagulation-fibrinolysis system has been studied in two groups of 16 patients classified ASA 1 undergoing radical mastectomy during controlled hypotensive anesthesia induced by prostaglandin E1 (PGE1) or by trimethaphan (TMP) under enflurane anesthesia. Thrombelastography (TEG) was used to evaluate both coagulation and fibrinolysis systems, while simultaneously measuring platelet aggregation in response to ADP and collagen, prothrombin time (PT), activated partial thromboplastin time (APTT), serum concentrations of fibrinogen, and platelet counts. In the PGE1 group, APTT was significantly shortened (P less than 0.05) while the drug was being infused, but there was no statistically significant difference between the two groups, which was considered due to the effect of enflurane. Also, no statistically significant changes were noted in the other measured parameters. These results suggest that controlled hypotensive anesthesia using either PGE1 or TMP under enflurane anesthesia produces no significant changes in the blood coagulation-fibrinolysis system and that both are useful for the management of bleeding during surgery. Further, TEG was found to reflect other parameters properly. It is therefore useful for monitoring the blood coagulation-fibrinolysis system during anesthesia.

Adult↗
PubMed1992

[Hemodilutional and blood salvaging autotransfusions in a case of aplastic anemia].

A 28-year-old female, weighing 46 kg, 155 cm in height, with aplastic anemia underwent implantation of iliac bone to the head of the femur. A combined technique of hemodilution and intraoperative blood salvaging was applied to supplement the blood loss during the operation. Intraoperative monitoring included continuous arterial pressure, heart rate, electrocardiograph, SVO2, bleeding time, prothrombin time (PT), activated thromboplastin time (APTT), and thromboelastography. A total of 900 ml of blood was drawn and the same volume of 5% albumin solution was infused over half an hour before the beginning of the surgery. During the operation, 2100 ml of blood was lost, and 1260 ml of autologous blood, 400 ml of homogeneous red blood cells and 5 units of fresh platelet were infused. The values of PT, APTT, bleeding time were within normal ranges after the surgery. Only 3 units of fresh platelet was infused in 2 weeks after the surgery. It was suggested that hemodilution and salvaging autotransfusion is safely performed and beneficial to minimize homogeneous blood transfusion even in a case of aplastic anemia.

Adult↗
PubMed1991

[Continuous infusion of ketamine and midazolam for prolonged sedation in the intensive care unit].

The clinical effects and pharmacokinetics of ketamine and midazolam, administered continuously for prolonged sedation were studied in 7 critically ill patients under mechanical ventilation. Initially ketamine 1 mg.kg-1 and midazolam 0.1 mg.kg-1 were administered intravenously and these were followed by infusion at a rate of 1.0 mg.kg-1.hr-1 of ketamine and 0.05 mg.kg-1.hr-1 of midazolam. The infusion rate was changed every 30 minute with increments of 0.5 mg.kg-1.hr-1 of ketamine and 0.05 mg.kg-1.hr-1 of midazolam until the sedative score by Ramsy RAE reached rank 4 (i.e. slow response to loud verbal commands). The plasma concentrations of ketamine were analyzed using high performance liquid chromatography and those of midazolam using gas chromatography. The mean maintenance doses of ketamine and midazolam were 2.25 +/- 0.61 mg.kg-1.hr-1 and 0.11 +/- 0.05 mg.kg-1.hr-1 (mean +/- SD), respectively. There were no significant changes in blood pressure or heart rate before and after the injection of ketamine and midazolam in all the patients. The plasma concentrations of ketamine and midazolam were 2.98 +/- 0.20 micrograms.ml-1 and 494.1 +/- 66.7 ng.ml-1, respectively. The time to clear response to verbal commands after cessation of the continuous infusion was 168 +/- 109 min. The plasma concentrations of ketamine and midazolam decreased rapidly, and plasma half-life of ketamine was about 1 hour and for midazolam less than 2 hours. In conclusion, continuous infusion of ketamine and midazolam was very useful to sedate critically ill patients under mechanical ventilation, with minimal effect on the cardiovascular system and rapid recovery of consciousness.

Adult↗
PubMed1991

[A case of brain metastasis of rhabdomyosarcoma in a child].

We report here a specific case of metastatic brain tumor orienting from rhabdomyosarcoma. An 11-year-old boy came to our hospital with complaints including headache, exophthalmos and tumors in the right frontal and left occipital region. 6 months previously subtotal removal of rhabdomyosarcoma in his right foot had been performed. CT scan demonstrated tumors in the right orbit, right frontal region and left occipital region. The tumors existed bilaterally in the skull and markedly enhanced by contrast medium. But the changes of the cranium were mild, only the dipole was slightly dilated. MRI showed that the tumors were extraaxial masses. Right external carotid angiogram revealed numerous tumor vessels fed by the meningeal artery. On April 3rd, biopsy was performed at the right frontal region. The tumor had spread in the epidural space but the cortical surface seemed to be intact. Histologically, the tumor consisted of small round cells and revealed multinuclear giant cells. It involved the skull bone, dura mater and subdural tissues. Accordingly the tumor was diagnosed as rhabdomyosarcoma. Although tumor increased rapidly, the intracranial region did not change remarkably. It was an interesting phenomenon. Eventually, rhabdomyosarcoma metastasized to the lung, and the patient died due to respiratory distress.

Brain Neoplasms↗
PubMed1991

[Interpleural administration of 1.0% and 1.5% lidocaine with epinephrine for pain relief after thoracotomy].

Pain relief following thoracotomy and arterial concentration profiles after interpleural administration of lidocaine were studied in 23 adult patients. They were allocated to three groups and given interpleural injection of 20 ml each of 1.0% (group 1, N = 9, non-pneumonectomy patients), 1.5% (group 2, N = 10, non-pneumonectomy patients), and 1.5% (group 3, N = 4, pneumonectomy patients) lidocaine with epinephrine (5 micrograms.ml-1). Complete pain relief was obtained within 20 min after injection in all patients. The mean duration of analgesia was 2.8 hr, 3.1 hr, and 5.1 hr in group 1, 2, and 3, respectively. The maximum plasma concentrations of lidocaine (Cmax) were 1.7 +/- 1.0 (mean +/- SD) microgram.ml-1, 2.2 +/- 0.6 micrograms.ml-1, and 0.7 +/- 0.2 micrograms.ml-1 in group 1, 2, and 3, respectively. The mean duration of analgesia was significantly longer in group 3 than in group 2 (P less than 0.01). Cmax was significantly lower in group 3 than in group 2 (P less than 0.01). In conclusion, we consider interpleural injection of lidocaine with epinephrine to be an effective method of providing postoperative analgesia after thoracotomy. Our data also suggest that the duration of analgesia may increase and the plasma levels of lidocaine may remain quite low in total pneumonectomy patients, because local anesthetic solution is not absorbed through the visceral pleura but absorbed only through the parietal pleura alone in these patients.

Adult↗
PubMed1985

Aneurysms associated with fenestrated anterior cerebral arteries. Report of four cases and review of the literature.

Four cases of aneurysms associated with a fenestrated anterior cerebral artery are presented. The combination of aneurysms and fenestration of the anterior cerebral artery is rare, and nine cases including ours have been reported. In all cases fenestrations were found within the distal two-thirds of the horizontal portion of the anterior cerebral artery. It may be presumed that fenestration of the anterior cerebral artery is the remnant of the plexiform anastomosis in the fetal stage, especially between the anterior cerebral artery and the primitive olfactory artery.

Aged↗
PubMed1981

Brain tumors in tuberous sclerosis. Report of 4 cases.

We report on 4 cases of brain tumors associated with tuberous sclerosis. In each case the tumor was in the region of Monro's foramen and was associated with ventricular dilatation. Computer tomography scans, which were performed in 3 cases, revealed well-circumscribed high-density masses which were markedly enhanced by contrast medium. 3 patients underwent craniotomy. Total extirpation was performed in 2 patients. Both of them are doing well postoperatively. However, 1 patients whose tumor had been partially resected died of recurrence 6 years after surgery. The pathology of three tumors was different in each case: plump cell astrocytoma, hemangioma and astroblastoma.

Adolescent↗