Showing papers in "Masui. The Japanese journal of anesthesiology in 1997"

[Which laryngoscope is the most stressful in laryngoscopy; Macintosh, Miller, or McCoy?].

Abstract: Stress responses during laryngoscopy were compared among the situations using three different laryngoscopes, Macintosh (curved standard blade), Miller (straight blade), or McCoy (levering). Blood pressure, heart rate (in 58 patients) and plasma concentration of catecholamines (in 29 patients) were measured before, during and after laryngoscopy without tracheal intubation. Systolic blood pressure after laryngoscopy was significantly higher in the Miller group than in other two groups. Plasma epinephrine concentrations after laryngoscopy in the McCoy group were lower than other two groups. Heart rate and plasma norepinephrine concentration were not different among the three groups. These results suggest that the stress response during laryngoscopy without intubation is the biggest in using the Miller laryngoscope and the smallest in using the McCoy laryngoscope.

[Respiratory arrest after a ventriculoscopic surgery in infants: two case reports].

Abstract: Case-1: A 4 month old, 7120 g, girl with hydrocephalus underwent endoscopic fenestration of the septum pellucidum. Her development had been normal without signs or symptoms of intracranial hypertension. She had no history of convulsion or apnea. Ventriculoscopic diagnosis was complete obstruction of the right foramen of Monro and partial defect of right ependyma. Intraoperative course was uneventful under general anesthesia. She had two episodes of respiratory arrest accompanied with myoclonus and the left conjugate deviation 15 min after extubation. Postoperative CT scan showed no abnormal findings such as intracranial hemorrhage. The respiratory arrest and conjugate deviation disappeared after phenobarbital administration. She had no further respiratory arrest. Case-2: A 1-month old boy with congenital hydrocephalus underwent endoscopic third ventriculostomy. He had no signs or symptoms of intracranial hypertension. CT scan showed enlargement of lateral ventricle and third ventricle due to aqueductal stenosis. Respiratory arrest was noted 10 min after extubation in the recovery room. His anterior fontanel sank abnormally and rigidity of the extremities was observed. His trachea was reintubated and he was transferred to ICU. After 24 h of respiratory care in the ICU he was extubated and discharged to the ward. He had no further episodes of respiratory arrest. We believe that postanesthetic apnea monitoring is mandatory in young infants who undergo ventriculoscopic surgery.

Effects of thiopental and sevoflurane on hemodynamics during anesthetic management of electroconvulsive therapy

Abstract: The effect of thiopental and sevoflurane (1 MAC, 2 MAC) on hemodynamics was assessed in a randomized study involving 38 adult patients undergoing electroconvulsive therapy (ECT). Blood pressure, heart rate and electrocardiogram (ECG) were monitored during the ECT procedure. After oxygenation, hypnosis was induced with a bolus injection of thiopenal (TPS) 4 mg.kg-1. Muscle relaxation was achieved by succinylcholine, 1 mg.kg-1 intravenously before ECT procedure. Ventilation was assisted using a face mask with 100% oxygen (TPS group), 1.7% sevoflurane (1 MAC group) or 3.4% sevoflurane (2 MAC group), plus 50% nitrous oxide and 50% oxygen. Thereafter, an electrical stimulus was administered. A total of 150 treatment sessions were evaluated. The rate pressure product increased in every group right after ECT, but the use of sevoflurane (2 MAC) significantly diminished the response compared with sevoflurane (1 MAC) and thiopental. In the sevoflurane (2 MAC) group, no ventricular arrhythmias were observed. In general, it seems that sevoflurane (2 MAC) is as effective as thiopental and sevoflurane (1 MAC) as an induction agent for ECT.

Decreasing heart rate and shortening of the arterial pulse propagation time by acupuncture in the spectral analyses

Abstract: By utilizing NAITO's analytical indices of the high frequency energy (HFEI) [sigma p x f (0.15 Hz < frequency < 0.45 Hz)] and the low frequency energy (LFEI) [sigma p x f (0.025 Hz < f < 0.15 Hz)] of R-R intervals combined with UEDA's index of fluctuation in propagation time of radial arterial pulses (i.e. R-P intervals), the author investigated relation between elongation in R-R and shortening in R-P intervals by application of electrical acupuncture (1 Hz) on traditional acupoints (HT7:SHENMEN and PC4: XIMEN). The spectral heart rate analyses have been performed in 16 males and 14 females (total 30, i.e. 18 physically healthy volunteers and 12 patients). Those who were suffering from any cardiovascular diseases were excluded. Results obtained are as follows; (1) The mean R-R intervals were significantly prolonged from 10 minutes after needle insertion to the end, i.e. 10 minutes after removal of the needles. (2) The R-P intervals were significantly shortened after 10 minutes of needle insertion. It is assumed that the decrease in heart rate by acupuncture was due to relative superiority of the vagal tone and the shortened R-P intervals, and was due to sympathetic nerve activities stimulated by acupuncture, so as to expedite arterial pulse wave propagation by the arterial contraction. Thus, increased activities of both sympathetic and vagal nerves can coexist simultaneously during acupuncture.

Breakage of a Seldinger spring guide wire during percutaneous catheterization of a subclavian vein

Abstract: Spring guide wires have been widely used for the central venous catheterization with the popularity of the Seldinger technique. We report here an accidental breakage of a spring guide wire during percutaneous catheterization of a subclavian vein. The venipuncture by a plastic catheter over an introducer needle and the insertion of a spring guide wire through the catheter were easily achieved. However, the insertion of an indwelling catheter over the guide wire was difficult to perform, and the pulling out of the guide wire from the catheter was more difficult, which brought the uncoiling of the spring part of the guide wire from the mandrel. The tip of the guide wire was not cut off, and there were no sequelae in the patient. A plastic catheter over an introducer needle for a subclavian venipuncture is so flexible that it is occasionally bent between the clavicle and the first rib after pulling out of the inside needle. Probably, that is the reason of the difficulties of the insertion of an indwelling catheter and the pulling out of a guide wire. The use of a rigid metal needle for the venipuncture is an alternative way to avoid these troubles.

[A risk of pulmonary edema associated with G-CSF pretreatment].

Abstract: We reported a case of severe pulmonary edema in the normal adult after bone marrow harvesting (BMH), who had received granular cell stimulating factor (G-CSF) pretreatment. The patient was 38 year old healthy man who was a donor to his son suffering from SCID (severe complicated immunodefficiency). He was administered total of G-CSF 750 mcg for three days before BMH. At the end of the BMH procedure, the patient was becoming dyspneic followed by severe pulmonary edema that continued about 8 hours. The levels of TNF alpha and IL-6 in his plasma and endotracheal exudate were abnormally as high as 10 and 130 pg.ml-1 of TNF alpha in plasma and exudate respectively and as 51.8 pg.ml-1 of IL-6 in plasma. We speculate that G-CSF activates white cells and induces leaking of cytokines from white cells, and the severity of pulmonary edema is associated with the cytokines.

Effectiveness of clonidine in postoperative nausea and vomiting - Epidural versus oral administration

Abstract: We investigated antiemetic effect of clonidine in postoperative nausea and vomiting (PONV) after laparoscopic cholecystectomy. One hundred and fifty nine patients were female, and were ranged in age 20 to 60 years. The body mass index of the patients was less than 30, and duration of operation was within 120 minutes. All patients received general anesthesia combined with epidural analgesia. One hundred and fifty nine patients were randomly divided into three groups: control group (n = 53); epidural group (n = 53) which received clonidine 150 micrograms epidurally before incision, oral group (n = 53) which received clonidine 150 micrograms orally 60-90 min prior to arrival in the operating room. The overall incidence of PONV during the first 12 h postoperatively was smaller in epidural group (15.1%, P < 0.01) and in oral group (7.5%, P < 0.05) compared with control group (32.1%). The incidence of PONV during the first postoperative hour was significantly smaller in epidural group (3.8%, P < 0.01) and in oral group (3.8%, P < 0.01) compared with control group (18.9%). Postoperative analgesic requirement was not significantly different among the three groups. We conclude that oral or epidural clonidine decreased the incidence of early PONV after laparoscopic cholecystectomy.

Aprotinin 2 million KIU reduces perioperative blood loss in patients undergoing primary total hip replacement

Abstract: We investigated consecutive patients undergoing primary total hip replacement surgery who were randomly assigned into two groups; those who received a blinded solution of aprotinin 2 million KIU (kallikrein inactivation units) (n = 11) and those who received an equivalent volume of normal saline placebo (n = 10) throughout the surgical procedure. Anesthesia and surgical techniques were standardized. All patients received spinal anesthesia combined with general anesthesia. There was no significant difference in blood loss during operation between the two groups. However, postoperative blood loss in the aprotinin group (284 +/- 155g, mean +/- SD) was significantly less compared with that in the control group (723 +/- 334g). Total blood loss in the aprotinin group (820 +/- 255g) was also significantly less than in control group (1265 +/- 389g). We conclude that the use of aprotinin 2 million KIU during total hip replacement results in significantly less perioperative blood loss, especially during the postoperative period.

[The pharmacokinetics of D-lactate, L-lactate and acetate in humans].

Abstract: In this study, the pharmacokinetics of D-lactate, L-lactate and acetate were investigated in 36 adult surgical patients. After induction of general anaesthesia, the subjects received intravenous injection of either 5 mmoles of D-lactate and 5 mmoles of L-lactate simultaneously (Group DL), 10 mmoles of L-lactate (Group L), or 10 mmoles of acetate (Group A). Serial arterial blood samples were obtained before the injection, and 3, 5, 7, 9 and 11 minutes after the infusion of each preparation. Plasma concentrations of D-lactate, L-lactate and acetate were measured by high performance liquid chromatography, enzymatic analysis and spectrophotometry. The pharmacokinetic parameters; distribution volume (Vd) and half-life (t1/2) were calculated with a one-compartment model from the incremental plasma concentration decay curve after administration. In Group DL, there were no differences between D-lactate and L-lactate in Vd and t1/2. Also, between L-lactate in Group DL and that in Group L, there were no differences in Vd and t1/2. The Vd and T1/2 of acetate, however, were smaller than those of L-lactate in Group L. We conclude that the pharmacokinetics of D-lactate is similar to those of L-lactate, and that acetate may be metabolized more rapidly than L-lactate.

The effect of sevoflurane on regional cerebral metabolism and cerebral blood flow in rhesus monkeys

Abstract: The effects of sevoflurane on cerebral metabolism and hemodynamics were studied in rhesus monkeys. Cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMR O2) as well as their regional changes were measured by means of positron emission tomography technique. After the measurement of regional CBFs and CMR O2s at 1.5% sevoflurane as control, the measurement was repeated at 3.0% sevoflurane and at the same sevoflurane concentration with the infusion of angiotensin II to restore mean arterial pressure. Regional CBFs and CMR O2s were compared among three different conditions. At 3.0% sevoflurane, regional CBFs increased significantly in response to the increase in the mean arterial pressure, suggesting the inhibition of autoregulation of CBF. However, regional CBF/CMR O2 ratio was not significantly different among the cerebral regions with each condition. It could be concluded that CBF during sevoflurane anesthesia up to 3.0% might become dependent on the cerebral perfusion pressure and the changes in regional CBFs varied among the regions. On the other hand, the ratio of oxygen consumption and delivery was well maintained throughout the brain regions.

[Repeated low-flow sevoflurane anesthesia: effects on hepatic and renal function in beagles].

Abstract: We studied the effects of repeated low-flow sevoflurane anesthesia for 6 hours. Five beagle dogs received 1.3 MAC (3%) sevoflurane anesthesia. Anesthesia of 6 hours was repeated on at the 7th day after the first anesthesia. Compound A gas samples were collected from the inspiratory limb during anesthesia. Concentrations of serum and renal fluoride, hepatic and renal function parameters were measured during and up to 7 days after the first and second anesthesia. The peak concentration of compound A was 23.7 +/- 3.6 ppm at 2 hours and the same level remained during the anesthesia. Plasma fluoride level exceeded 50 mmol.l-1 during anesthesia and rapidly decreased to the preanesthesia level thereafter. Serum GOT increased slightly only on the first postanesthesia day. No significant changes in other blood chemistry studies were observed. The excretion of renal tubular enzymes did not increase during and after anesthesia. Repeated low flow sevoflurane anesthesia in beagles did not affect hepatic and renal function significantly.

[Effects of olprinone on IL-6 and IL-10 production during and after cardiac surgery]

Abstract: Phosphodiesterase inhibitor (PDEI) has been accepted as an inodilator with positive inotoropic and vasodilating actions. Recently many new PDEIS have been available for the treatment of heart failure. We investigated the effect of a new PDEI-III agent, olprinone, on IL-6 and IL-10 production during and after coronary bypass graft surgery (CABG). Twelve patients scheduled for CABG were assigned to 2 groups. In 6 patients (Group-O), olprinone was administered continuously for 30 minutes at a rate of 0.3 micrograms.kg-1.min-1 (gamma) after the anesthesia induction. Then, the infusion rate of olprinone was decreased to 0.2 gamma and it was kept until the 3rd post-operative day. In another 6 patients (Group-C), phentolamine was used for vasodilator instead of olprinone. The plasma levels of IL-6 in Group-O did not show any significant change during perioperative period, whereas those in Group-C reached the peak at the end of extracorporeal circulation and did not recover to control level until the 3rd post-operative day. The plasma levels of IL-10 in Group-O increased to the maximum level at the end of extra-corporeal circulation and were significantly higher than those in Group-C. It is suggested that olprinone has not only inodilating action but also anti-inflammatory action at therapeutic concentrations used for heart failure.

Epidural anesthesia reduces mortality rate in the patients after emergency abdominal surgery

Abstract: Stress response and increased sympathetic stimulation constrict gastrointestinal blood vessels. In patients after abdominal surgery, anastomotic leakage and bacterial translocation may occur as a result of gastrointestinal hypoperfusion. These patients are at risk for severe SIRS and MOF, especially after emergency surgery. Epidural anesthesia decreases sympathetic stimulation and accordingly increases gastrointestinal blood flow. The purpose of this study was to test the hypothesis that epidural anesthesia has a beneficial effect on patients after emergency abdominal surgery. Seventy-seven patients older than 50 years of age having undergone emergency abdominal surgery were studied. Thirty-nine patients received general anesthesia alone (GA) and 38 patients received epidural anesthesia (EA). The data on APACHE II score, fluid intake and output management, mortality rate, and others of the subjects were collected from patient charts. The mortality rate 3 months after surgery in group GA (35.9%) was significantly higher than that in group EA (5.3%) (P < 0.01). There was no difference in APACHE II score and age. Fluid intake was significantly larger in group EA. To reduce mortality rate, epidural anesthesia and volume expansion are recommended for patients after emergency abdominal surgery.

[Effect of injection speed on sensory blockade in spinal anesthesia with 0.5% hyperbaric tetracaine].

Abstract: We investigation the effect of injection speed on sensory blockade in spinal anesthesia. Forty two female patients, scheduled for total abdominal hysterectomy, were allocated randomly to 3 groups of 14 each according to the injection speed of 0.5% hyperbaric tetracaine: Group F (fast; injection speed > or = 0.2 ml.s-1), Group M (moderate; 0.1 < injection speed < 0.2 ml.s-1) and Group S (slow; injection speed < or = 0.1 ml.s-1). Spinal puncture was performed via the median approach at the L3-4 interspace with the patient in a lateral position. The maximum level of sensory blockade was assessed by means of the pin-prick method in the midline 3, 5, 10, 20, 30, 60 minutes after injection. In Group F, the level of sensory blockade became higher quickly (within 5 min), but anesthetic effects were not so satisfactory. And, in this group, there were more patients with dyspnea than in other groups. We speculate that the turbulence made by fast injection in subarachnoid space caused unsatisfactory effects. In Group S, anesthetic level was becoming higher also 20 or 30 min after injection. The fixation of anesthetics requires about 30 min. In our opinion, anesthetics injected slowly were diluted less by CSF, and the actual baricity of them was higher, and this made the difference within 30 min. In Group M, anesthetic effects and patient's condition were stable. We suppose that this injection speed (0.1-0.2 ml.s-1) is suitable for spinal anesthesia.

Preoperative flurbiprofen provides pain relief after laparoscopic cholecystectomy

Abstract: In a single-blind randomized prospective study, postoperative pain was assessed in 60 patients undergoing elective laparoscopic cholecystectomy with three types of anesthesia: standardized general anesthesia (control group), preoperative 50 mg flurbiprofen as an addition to the same method of general anesthesia (flurbiprofen group), and conventional combined epidural and general anesthesia with epidural administration of 0.25% bupivacaine 5-8 ml and 0.1-0.2 mg buprenorphine after surgery (epidural group). After the operation we found that the average time from the end of surgery to the first request for an analgesic was 3.9 h, 22.7 h and 43.7 h in the control, flurbiprofen and epidural group, respectively. Substantially it was longer in the flurbiprofen and epidural group than in the control group (P < 0.01 and < 0.001, respectively). Patients in the control group requested analgesics for a longer period of time after the initial request compared with patients in the other groups. Our results indicate that postoperative pain can be reduced when flurbiprofen is added to general anesthesia before surgery, although use of flurbiprofen was not as effective as the conventional combined epidural and general anesthesia used for treating pain after laparoscopic cholecystectomy.

Effect of controlled hypotension on cerebral oxygen delivery

Abstract: The margin of safety for controlled hypotension is still unclear especially in the central nervous system (CNS) which is one of the most sensitive organs to hypoxia and ischemia. Recently, cerebral optical spectroscopy in the infrared light range was developed as a useful tool which makes it possible to monitor cerebral oxygenation (rSO2) non-invasively and continuously during anesthesia. Resulting rSO2 mainly reflects oxygen extracts by cerebral tissue and then indicates cerebral oxygen delivery. We examined the limitation of controlled hypotension in the brain in 12 patients by monitoring rSO2 during anesthesia. rSO2 under room air breathing (control value as normal physiological condition) was 67 +/- 3% (mean +/- SEM). It significantly increased by 5.6 +/- 0.8% under 100% oxygen breathing, but decreased near to the control value under sevoflurane anesthesia (FIO2 1.0). During moderate controlled hypotension (70% of normal blood pressure) by prostaglandin E1 under sevoflurane anesthesia (FIO2 1.0). rSO2 remained at control value, indicating that cerebral oxygen delivery was still sufficiently maintained. However rSO2 decreased significantly by 9.0 +/- 1.1% in same controlled hypotension condition under FIO2 0.4. This decrease in rSO2 could be potentially harmful for CNS although any post-operative neurological disorder was not observed in our cases. We conclude that cerebral oxygen delivery may be insufficient even in the moderate controlled hypotension, and thus higher FIO2 is recommended in such procedures.

[Cuff damage during naso-tracheal intubation for general anesthesia in oral surgery].

Abstract: In our hospital, twenty-one cases of endotracheal tube cuff rupture during naso-tracheal intubation were noted in cases using 725 polyvinyl chloride (PVC) tracheal tubes. We analysed the causes of cuff troubles in these 21 samples of tubes. When the cuffs were inflated, they were not capable of containing the air in most cases. Some cuffs had small holes (described as pinholes), and the others had longer slits on scrape marks and burst. These scrape marks may have been caused by the object with sharp edges such as spina or crista of the nasal septum, or otherwise by the tip of intubation forceps. The cuff material appeared to be slightly hardened in some samples which may be due to the lubrication. We usually lubricated the tube with lidocaine spray or gel formulation and then sometimes placed it in hot water to soften it for avoiding naso-mucosal injury. It is not generally recommended to place tubes in hot water, as this procedure may soften the cuff and make it more suspectible to damage. The clarification is also needed on the use of lidocaine. Although the gel formulation is acceptable, but the spray formulation is known to react with cuff material and make it more susceptible to inducing blistering, pinholes and sudden rupture of PVC cuffs. We conclude that these cuff damages might have occurred from various causes. A main cause must be passing the tube through the narrow nasal turbinate with spina or crista. Other causes could not only be the use of Magill forceps but also lubrication of the tube with lidocaine spray and placing it in hot water.

The differences of the cerebral and spinal vessels in sensitivity to PaCO2 and vasoconstrictors

Abstract: We investigated the differences in the response to arterial CO2 tension and vasoconstrictors between the cerebral and spinal vasculatures using cranial and spinal window technique which provided the direct observation of pial vessels. Pentobarbital anesthetized dogs (n = 18) (CO2 tension; n = 6 and vasoconstrictor; n = 12) were instrumented for measurement of pial vessel diameters by intravital microscopy in the cranial and spinal window preparation simultaneously. We achieved hypocarbia (20-25 mmHg) followed by adjusting CO2 levels for normocarbia (35-40 mmHg) and for hypercarbia (55-60 mmHg) using CO2 gas addition. After obtaining the desired PaCO2, the measurements were made. In the next experiment, we administered 2 different concentrations of epinephrine or phenylephrine solutions (1:2 x 10(6), 1:2 x 10(5)) through the window, and the measurement was made sequentially. The response of cerebral and spinal vasculature to change in PaCO2 was almost similar. Topical application of both drugs produced a significant constriction of spinal pial arterioles compared with the cerebral ones, while epinephrine but not phenylephrine constricted cerebral pial venules compared with spinal ones. These results suggest that the responses to vasoconstrictor of cerebral and spinal pial vessels are not similar, and high sensitivity of spinal arterioles to vasoconstrictors may possibly contribute to a risk of ischemic damage of the spinal cord.

Two cases of anaphylactic shock induced by chlorhexidine

Abstract: We reported two patients who developed skin eruptions and severe hypotension immediately after scrubbing their wound in the leg using 4% chlorhexidine solution. Both patients were successfully treated by epinephrine administration. Patient-1 (a 42-year-old man) had his wound scrubbed using this antiseptic several times before the operation. He showed a positive skin scratch test for chlorhexidine. Patient-2 (a 74-year-old man) had no prior treatment with chlorhexidine. Positive lymphocyte transformation test was not demonstrated in these patients. It has been reported that more than 10% of patients with anaphylactic shock induced by chlorhexidine use had previous exposure to it and 80% of them had it used for mucosa or wound washing. From these results, we should keep it in mind that chlorhexidine is not likely to be a safe antiseptic and can possibly induce anaphylactic shock.

[Acute angle-closure glaucoma after total hip replacement surgery].

Abstract: Acute angle-closure glaucoma is a rare complication of surgery. We experienced a case of postoperative acute glaucoma after total hip replacement under general anesthesia. A 49-year-old female without signs or symptoms of glaucoma was premedicated with the intramuscular administration of secobarbital, atropine and ranitidine. Following rapid induction with thiopental and vecuronium, anesthesia was maintained with N2O-O2-sevoflurane. PGE1 was administered intravenously for induced hypotension during the surgery. Hemorrhagic shock with a systolic blood pressure of 60 mmHg continued for 15 min during the surgery. Large amounts of fluid and ephedrine were required for treating this hypotensive episode. Vecuronium was reversed by bolus injection of neostigmine and atropine at the end of surgery. Soon after recovery from anesthesia, she complained of pain and blurred vision in her both eyes. The consulting ophthalmologist made a diagnosis of acute glaucoma due to high intraocular pressure (IOP). Treatment with glycerol and pilocarpine had no effect on the elevated IOP. The laser iridotomy performed on her at 5th and 7th post-operative days improved her vision completely. The post-operative glaucoma may cause serious permanent loss of vision. An early diagnosis of this post-operative complication and its treatment with drugs and surgery should be emphasized.

Living related liver transplantation for patients with ornithine transcarbamylase deficiency

Abstract: Ornithine transcarbamylase deficiency (OTCD) is an inborn error of urea synthesis inherited as an X-linked trait, a clinical manifestation of which is a repeated episodes of hyperammonemic coma. Recently, liver transplantations have been performed in these patients in the USA and Europe. We experienced the anesthetic managements of liver transplantations in two OTCD patients, who had been suffering from several episodes of hyperammonemic decompensation despite a restricted protein diet with administration of sodium benzoate. Anesthesia was induced and maintained with a combination of fentanyl and midazolam in both cases. Their postoperative courses were good without any neurological damages, though one patient had hyperammonemic attack during the operation.

[Effect of nitrous oxide at sub-MAC concentrations on sevoflurane MAC in adults].

Abstract: The interaction of sevoflurane and nitrous oxide (N2O) on the MAC was studied in the four groups of patients between 30-60 years of age scheduled for laparotomies. Patients received one of four different concentrations of N2O [0% (n = 14), 25% (n = 16), 50% (n = 15), or 70% (n = 18)]. Anesthesia was induced with sevoflurane and N2O using a semiclosed circuit with a carbon dioxide absorber. After endotracheal intubation, sevoflurane and N2O end-tidal concentrations were adjusted to predetermined concentrations until the skin incision was made. The MAC values for sevoflurane in O2 and the presence of 25%, 50%, and 70% N2O were 1.68%, 1.33%, 0.82% and 0.55%, respectively. A regression analysis through all four data points yielded a linear relationship (r = -0.997). The requirement of sevoflurane decreased by approximately 1% for each 1% of N2O administered at three N2O concentrations. The extrapolated MAC value for N2O was 102%. The MAC values of sevoflurane in O2 and N2O were similar to the previously reported values. We conclude that in adults, N2O concentrations in the dose range 0-70% reduce sevoflurane MAC in a linearly additive manner.

[Sudden onset of bronchospasm and persistent hypotension during spinal anesthesia in a patient on long-term psychotropic therapy].

Abstract: We experienced perioperative management of a patient on long-term psychotropic therapy The patient was a 65-year-old man who underwent TUR of the prostate under spinal anesthesia Bronchospasm and persistent hypotension occurred immediately after the beginning of TUR Aminophylline improved bronchospasm, but it was difficult to keep blood pressure with continuous infusion of norepinephrine or epinephrine The patient recovered from anesthesia safely We should pay attention to bronchospasm as well as hypotension in a patient on long-term psychotropic therapy during perioperative period

[Effects of cardiac output on PETCO2 and PaCO2 during combined inhalational-epidural anesthesia]

Abstract: We investigated the effects of cardiac output on PETCO2 in anesthetized patients. We studied 8 adult patients undergoing long-lasting lower abdominal surgery. Anesthesia was maintained with epidural combined with inhalational anesthesia. The minute ventilation volume was kept constant at 10 ml.kg-1 x 10 cycles.min-1. PETCO2, PaCO2, and cardiac index, (CI) by thermodilution method were measured simultaneously. PaCO2 was corrected for body temperature for comparison with PETCO2. Approximate value of alveolar dead space to tidal volume ratio was calculated as VD/ VTalv = (PaCO2-PETCO2)/PaCO2. The measurements were repeated every 10 to 20 minutes under the steady body temperature. One hundred and six sets of data were obtained from these patients. PETCO2 as well as PaCO2 correlated positively with CI, while VD/VTalv did not correlate with CI. PETCO2 correlated positively with PaCO2, while it did not correlate with VD/VTa1v. When examined in individual patients, PETCO2 correlated positively with CI in 7 patients. PaCO2 correlated positively with CI in 6 patients, while VD/VTa1v correlated negatively with CI only in 2 patients, in whom CI showed a large fluctuation. PaCO2 correlated positively with PETCO2 in 8 patient, while VD/VTa1v correlated negatively with PETCO2 only in 1 patient. By multiple regression analysis, VD/VTa1v change accounted for only 20.0 +/- 15.3% of PETCO2 change, while PACO2 or PaCO2 change accounted for 79.3 +/- 16.7%. Decreased CI was associated with a decrease in oxygen uptake (VO2), and PaCO2 correlated positively with VO2. Decreased CI was also associated with an increase in VA/Q, and PaCO2 correlated negatively with VA/Q. Thus, PETCO2 decreased with decreasing cardiac output. A decrease in PACO2 explained the decrease in PETCO2 better than an increase in VD/VT did. Decreased cardiac output caused hypocapnia through decreased CO2 production and/or increased ventilation to perfusion ratio i.e. relative hyperventilation.

Cervical spine movement during orotracheal intubation using the McCoy laryngoscope compared with the Macintosh and the Miller laryngoscopes

Abstract: The movement of cervical spine during orotracheal intubation was compared using the McCoy, Macintosh or Miller laryngoscope blade. Twenty ASA 1-2 patients requiring tracheal intubation were studied. Following induction of anesthesia and obtaining muscle relaxation, the cross-table lateral X-ray was taken before and during laryngoscopy using three types of laryngoscopes. Degree of cervical spine movement was evaluated by measuring the distance between the spinous processes of C1 and the occiput, and the amount of displacement of C1 and C5 against C3 by tracing on each films. The results indicated that delta C1-occiput was larger and delta C1 + C5 smaller with the McCoy laryngoscope compared with the others. The use of the McCoy laryngoscope results in less cervical spine movement during laryngoscopy and therefore should be of particular benefit in the presence of cervical spine instability as well as in the normal patients.

The effects of caffeine on the respiratory depression by morphine

Abstract: The effects of intravenous administration of caffeine on the discharge of the phrenic nerve were studied following vagotomy in 7 pentobarbital anesthetized mechanically ventilated rats. Morphine (0.4 mg.kg-1.min-1) was administered until the respiratory rate decreased to about half of the baseline respiratory rate. In those state, we first administered caffeine (20 mg.kg-1), intravenously and then administered naloxone (0.02 mg) intravenously. The increase of inspiratory time from 0.49 +/- 0.16 to 2.01 +/- 0.47 s by morphine recovered to 0.86 +/- 0.38 s by caffeine and 0.50 +/- 0.22 s by naloxone. Expiratory time did not change during each drug administration. The decrease of respiratory rate from 46.6 +/- 5.9 to 20.6 +/- 4.1 breaths.min-1 by morphine recovered to 39.6 +/- 6.1 breaths.min-1 by caffeine and 47.6 +/- 4.6 breaths.min-1 by naloxone. Amplitude of integrated phrenic nerve discharge increased to 117 +/- 32% by caffeine and 156 +/- 39% by naloxone compared to the baseline. These results suggest that caffeine acts as a respiratory stimulant on the respiratory depression by morphine.

[Low flow anesthesia using a fresh gas flow of 600 ml.min-1 for 5 hours].

Abstract: Low flow anesthesia (LFA) using a fresh gas flow (FGF) of 600 ml.min-1 with oxygen and nitrous oxide flow each set at 300 ml.min-1, and dial setting of sevoflurane 3% was administered to 30 patients for a duration of 5 hours. There were no problems such as unsuitable concentrations of nitrous oxide and sevoflurane in inspired and expired gases or low FIO2 below 0.3 during anesthesia in 15 patients of group A. Their body weight was 53 +/- 5 kg. FIO2 decreased below 0.29 at about 4 hours in 7 patients of group B weighing 62 +/- 6 kg, and at about 1 h in 8 patients of group C weighing 71 +/- 7 kg. In group A and B, the sum of concentrations of oxygen, nitrous oxide and sevoflurane in inspired gas decreased for a moment and recovered as anesthesia progressed, but in group C, it kept decreasing without recovery. The body weight was significantly different among the 3 groups (P < 0.05). It was suggested that in group A the FGF per body weight was suitable; in group B though oxygen flow was larger than oxygen consumption, hypoxia occurred due to saturation of nitrous oxide in the body; and in group C the FGF was insufficient. The compound A was detected in the breathing circuit, and the concentration was around 20 ppm and it did not depend on the duration of LFA. It was concluded in this study that LFA using the FGF of 600 ml.min-1 with setting of 3% sevoflurane, 50% oxygen and nitrous oxide, could be performed safely without risks such as hypoxia and severe delay of induction for patients weighing 53 +/- 5 kg for a duration of 5 hours.

Clinical use of midazolam

Abstract: Midazolam is widely used in anesthesia. This paper shows characteristics of midazolam and how to use midazolam in clinical anesthesia. As a premedication, midazolam should be injected i. m. 15 min before entering an operating room in a dose of 0.04 mg.kg-1 to 0.08 mg.kg-1 according to the patient's age. For anesthesia induction, midazolam should be used together with barbiturate or propofol to take advantage of synergistic effects. Continuous infusion of midazolam in total intravenous anesthesia with fentanyl results in hemodynamic stability and good postoperative analgesia. During spinal or epidural anesthesia, i.v. midazolam of 0.05 mg.kg-1 has anti-anxietic and sedative effects. Midazolam inhibits awakening during cardiopulmonary bypass and it has little cardiodepressant effect. In aged, hepatic damaged or renal damaged patients, the effects of midazolam are slightly increased. Therefore, lower doses may be required in such patients. In conclusion, midazolam is usable in premedication, induction, maintenance in general anesthesia and in sedation in local anesthesia.

Effect of controlled hypotension induced by prostaglandin E1 on evoked spinal cord potential and spinal cord blood flow

Abstract: We evaluated the effect of controlled hypotension induced by PGE1 on evoked spinal cord potential (ESCP) and spinal cord blood flow (SCBF) in 14 patients undergoing laminectomy or laminoplasty They were divided into two groups: hypotensive group (group H), non-hypotensive group (group N) Controlled hypotension was induced with PGE1 to maintain mean arterial blood pressure at 55-60 mmHg for 45 min The amplitude and latency of the N 1 potential were analyzed, and the SCBF was estimated by laser doppler flowmeter There were no significant differences in ESCP and SCBF These results suggest that controlled hypotension by PGE1 maintained normal local spinal cord blood flow autoregulation

[Effect of dibucaine and lidocaine on histamine release from mouse bone marrow-derived cultured mast cells].

Abstract: We examined the effects of dibucaine and lidocaine on histamine release from mouse bone marrow-derived cultured mast cells. The effects of these drugs on intracellular calcium were also monitored by assessing Fura-2 signals. Additionally, the inhibitory effects of lidocaine on IgE dependent and independent stimuli were examined. Though dibucaine induced histamine release and increases in intracellular calcium from mast cells dose-dependently, lidocaine did not. Lidocaine inhibited both the IgE-dependent and independent histamine release from mast cells in a dose dependent manner. However, the ability of lidocaine to inhibit the IgE-dependent response was greater. Lidocaine also inhibited increases in intracellular calcium to a greater extent after IgE-dependent stimulation as compared with IgE-independent stimulation. The degree of the inhibition of histamine release by lidocaine appeared to parallel decreases in calcium mobilization.