Levobupivacaine-dextran mixture for transversus abdominis plane block and rectus sheath block in patients undergoing laparoscopic colectomy: a randomised controlled trial

We performed a randomised controlled double-blinded study of patients having laparoscopic colectomy with bilateral transversus abdominis plane block plus rectus sheath block, comparing a control group receiving 80 ml levobupivacaine 0.2% in saline with a dextran group receiving 80 ml levobupivacaine 0.2% in 8% low-molecular weight dextran. Twenty-seven patients were studied in each group. The mean (SD) maximum plasma concentration of levobupivacaine in the control group (1410 (322) ng.ml(-1) ) was higher than the dextran group (1141 (287) ng.ml(-1) ; p = 0.004), and was reached more quickly (50.6 (30.2) min vs 73.2 (24.6) min; p = 0.006). The area under the plasma concentration-time curve from 0 min to 240 min in the control group (229,124 (87,254) ng.min.ml(-1) ) was larger than in the dextran group (172,484 (50,502) ng.min.ml(-1) ; p = 0.007). The median (IQR [range]) of the summated numerical pain rating score at rest during the first postoperative 24 h in the control group (16 (9-20 [3-31]) was higher than in the dextran group (8 (2-11 [0-18]); p = 0.0001). In this study, adding dextran to levobupivacaine decreased the risk of levobupivacaine toxicity while providing better analgesia.

Increased heart rate variability correlation between mother and child immediately pre-operation

BACKGROUND

Maternal distress would correlate with the children's mental status, thereby influencing the activity of the autonomic nervous system (ANS) of the children and mothers. We hypothesized that pre-anesthetic maternal ANS activity, when approaching close to their children's operation time, would correlate with children's ANS activity, and that the values of heart rate variability (HRV) would correlate.

METHODS

We calculated maternal and children's HRVs and analyzed the relationship between the two. A total of 24 pairs of mother and child were analyzed. Maternal and children's HRVs were recorded from the night before the child's surgery to the arrival to the operation room.

RESULTS

The ratios of low-frequency components (LF) to high-frequency components (HF) (LF/HF ratio) of children's and maternal HRVs obtained during the immediate pre-operative period (06:00-08:00 hours) showed a significantly, positive correlation, but no correlation was found for the LF/HF ratios obtained during the pre-operative night.

CONCLUSION

The LF/HF ratios of HRV immediately before surgery in children and mothers showed a significant positive correlation.

Intra-articular injection of warmed lidocaine improves intraoperative anaesthetic and postoperative analgesic conditions

BACKGROUND

Although local anaesthesia for knee arthroscopy is a well-documented procedure, arthroscopy under local anaesthesia is often interrupted because of intolerable discomfort and pain. Warming local anaesthetic solutions may increase its anaesthetic effect. We tested whether intra-articular injection of warmed lidocaine solution could improve intraoperative anaesthetic and postoperative analgesic conditions.

METHODS

Patients in the warmed group received 20 ml warmed (40 degrees C) lidocaine 1% intra-articularly 20 min before surgery. The patients in the control group received 20 ml room-temperature (25 degrees C) lidocaine 1% intra-articularly 20 min before surgery. During surgery, the patients reported pain on a visual analogue scale (VAS).

RESULTS

The median VAS pain score was 1.5 (range, 0.0-3.0) in the warmed lidocaine group and 5.0 (4.0-8.0) in the control group (P<0.001). The median intra- and postoperative analgesic requirements in the control group were significantly greater than that in the warmed group.

CONCLUSION

Warmed lidocaine injected intra-articularly provides improved intraoperative anaesthetic and postoperative analgesic conditions for patients undergoing knee arthroscopy.

Pre-anesthetic presence of an injured dam influences pups' locomotor behavior during emergence from anesthesia in rats

BACKGROUND

Pre-anesthetic mother-infant interaction is an important factor for smooth emergence of pediatric anesthesia. In many mammalian species, disruptions of the mother-infant relationship cause psychological and behavioral changes. This study was to investigate whether or not pre-anesthetic presence of an injured dam has an impact on locomotor behavior of rat pups.

METHODS

We used a video-tracking system to test the effects of pre-anesthetic relations between pups and their dams on pups' locomotor behavior during emergence from general anesthesia, in 40 3-week-old Sprague-Dawley male rats. Pups were divided into two groups: pups housed with a dam (n = 20) and those housed with an injured dam (n = 20). Pups were anesthetized with 1.2% halothane for 30 min. At emergence, we recorded their locomotor behavior for 15 min.

RESULTS

Pre-anesthetic manipulation to dams significantly increased the distance traveled by pups. However, the manipulation did not cause any difference in the maximum velocity.

CONCLUSION

Pre-anesthetic presence of an injured dam influenced pups' locomotor behavior at emergence from anesthesia.

Preoperative stellate ganglion blockade prevents tourniquet-induced hypertension during general anesthesia

BACKGROUND

Prolonged and excessive inflation of pneumatic tourniquets leads to a hyperdynamic circulatory response. Sympathomimetic activity is an important factor in tourniquet-induced hypertension. Stellate ganglion block specifically blunts sympathetic efferent nerves and prevents hypertension induced by sympathomimetic stimulation. The present study was performed to investigate the effects of stellate ganglion block (SGB) on arterial pressure and heart rate during prolonged tourniquet use under general anesthesia.

METHODS

Twenty patients scheduled for knee arthroscopy were either treated with 10 ml of 1% lidocaine for SGB (SGB group; n = 10), or intramuscular injection (IM group; n = 10) before tourniquet inflation. Comparisons of systolic and diastolic arterial pressure and heart rate were made before and after the induction of anesthesia, 10 min after the lidocaine treatment, every 5 min during the first 60 min after tourniquet inflation, and immediately before and 5 min following deflation. The maximum values of the circulatory variables were compared.

RESULTS

Tourniquet inflation caused increases in the circulatory variables in both groups. Systolic arterial pressure in the SGB group was significantly lower than that in the IM group after 55 min of tourniquet inflation. Diastolic arterial pressure also was significantly lower in the SGB group immediately before the deflation. The maximum values of the three hemodynamic variables were significantly lower in the SGB group. Arterial pressure significantly decreased after tourniquet deflation in the IM group.

CONCLUSION

Ipsilateral SGB attenuated the hyperdynamic response mediated by prolonged tourniquet inflation during knee arthroscopy.

Pre-anesthetic maternal separation increases pups' locomotor behavior during emergence from anesthesia in rats

BACKGROUND

Problematic behavior at emergence from anesthesia in children, partly linked with maternal separation, is a major problem in pediatric anesthesia. In humans, as well as in many other mammalian species, such separation causes psychological and behavioral changes. This study was to investigate whether or not pre-anesthetic maternal separation has a similar effect on rat pups.

METHODS

This study was conducted on 66 3-week-old Sprague-Dawley male rats. The rats were divided into two groups; pups housed with a dam (n = 33) and those housed without (n = 33). Pups were anesthetized with 1.2% halothane for 30 min. Afterwards we recorded their locomotor behavior at emergence from general anesthesia using a video tracking system.

RESULTS

Pre-anesthetic maternal separation significantly increased the maximum velocity and the distance traveled by pups at the emergence.

CONCLUSION

Pre-anesthetic maternal separation influenced pups' locomotive behavior at emergence.

Haemodynamic effects of the lateral decubitus position and the kidney rest lateral decubitus position during anaesthesia

We measured the haemodynamic effects of changing from the supine position to the lateral decubitus (lateral) position, and then to the kidney rest lateral decubitus (kidney) position in 12 patients undergoing nephrectomy under isoflurane anaesthesia. Eight control patients undergoing pulmonary surgery remained in the lateral position. The lateral position produced no significant changes. In the kidney position, however, significant reductions occurred in the mean arterial (P < 0.01), right atrial (P < 0.05) and pulmonary artery wedge pressures (P < 0.01). There were also significant reductions in cardiac index (from 3.04 (SD 0.21) to 2.44 (0.26) litre min-1 m-2, P < 0.01) and stroke volume index (from 40 (5) to 31 (5) ml beat-1 m-2, P < 0.01). The systemic vascular resistance index increased significantly (P < 0.05). Cardiac output was probably reduced by a decrease in venous return and an increase in systemic vascular resistance.

Increased production of interleukin-10 by human blood monocytes stimulated with Mycobacterium avium-intracellulare complex

Macrophages produce various cytokines in response to mycobacteria, including interleukin 10 (IL-10) and tumor necrosis factor alpha (TNF-alpha). IL-10 has been shown to down-regulate numerous macrophage functions, including microbicidal activity against intracellular bacteria and parasites. IL-10 also inhibits interferon-gamma (IFN-gamma) production and antigen-specific proliferation of Th1 cells mediating immunologic resistance to mycobacterial infection. In contrast, TNF-alpha activates macrophages and may augment their mycobacterial activity. In this study, peripheral blood mononuclear cells (PBMC) or blood monocytes obtained from healthy tuberculin reactors were stimulated in vitro with heat-killed Mycobacterium tuberculosis or heat-killed M. avium-intracellulare complex (MAC) to produce IL-10 and TNF-alpha. We studied a total of 26 clinical isolates of M. tuberculosis and 28 isolates of MAC. MAC-stimulated PBMC and monocytes released significantly larger amounts of IL-10 than those cells stimulated with M. tuberculosis. However, there was no difference in induction of TNF-alpha production between MAC and M. tuberculosis. When TNF-activity was neutralized by the addition of anti-TNF-alpha mAb in culture, MAC still induced more IL-10 secretion than did M. tuberculosis. These findings suggest that increased production of IL-10 by MAC-stimulated monocytes may play a role in the intractable disease caused by these organisms.

[A case of pheochromocytoma incorrectly diagnosed before and during surgery]

In a patient with an adrenal tumor, although norepinephrine levels in the blood and urine were abnormally high, findings in CT and 131 I-MIBG scintigraphy denied pheochromocytoma. The preoperative diagnosis was metastatic adrenal tumor. The surgical manipulation of the tumor increased the blood pressure from 110/60 to 210/110 mmHg. However, intraoperative microscopic examination in frozen section excluded again possibility of pheochromocytoma. Later, findings in the permanent specimen confirmed that the tumor was pheochromocytoma. The problem of this case was that each specialist made judgment only on the subject of his own interest without considering of the patient's status as a whole. Anesthesiologist should have the ability to make preoperative assessment of a patient by using all available information with his unbiased mind.

Greater incidence of delirium during recovery from sevoflurane anesthesia in preschool boys

BACKGROUND

In the authors' clinical experience, preschool children are more likely to show delirium after sevoflurane than are older children.

METHODS

Sixty-three preschool boys aged 3-5 yr (classified as American Society of Anesthesiologists [ASA] physical status I), and 53 school-age boys aged 6-10 yr (ASA physical status I) who underwent minor urologic surgery were randomly assigned to receive either halothane or sevoflurane, thus creating four groups: preschool-halothane (n = 32), preschool-sevoflurane (n = 31), school-halothane (n = 27), and school-sevoflurane (n = 26). Anesthesia was induced by inhalation of halothane or sevoflurane in oxygen and was maintained at 1 minimum alveolar concentration of each agent throughout surgery. For intra- and postoperative analgesia, caudal block with 0.5-1.0 ml/kg 0.25% plain bupivacaine and topical infiltration with 3-5 ml 1% lidocaine were provided for all patients. Recovery characteristics and incidence of delirium on emergence were compared among the four groups.

RESULTS

Two patients in the preschool-halothane group, one in the preschool-sevoflurane group, and one in the school-halothane group were excluded from the comparison because of insufficient analgesia or agitation before induction. In both age groups, the time to emergence from sevoflurane was significantly faster (about 3 min) than from halothane. The incidence of delirium during recovery in the preschool-sevoflurane group (40%) was significantly greater than that in the other groups (preschool-halothane, 10%; school-halothane, 15.4%; school-sevoflurane, 11.5%).

CONCLUSION

Sevoflurane provided quicker emergence and early recovery compared with halothane, but the incidence of delirium was greater in preschool boys after sevoflurane.

Differences in hormonal responses to preoperative emotional stress between preschool and school children

BACKGROUND

The behavior of children under emotional stress differs according to whether they are of preschool or school age.

METHODS

To examine the effect of age on hormonal responses to preoperative emotional stress, we measured the concentrations of catecholamines (adrenaline and noradrenaline) and cortisol in 56 healthy boys before surgery.

RESULTS

Among preschool boys (3-5 years old), those showing anxious behavior showed significantly higher cortisol, adrenaline, and noradrenaline concentrations in the blood circulation than those not showing such behavior (P < 0.0001, P < 0.0001 and P < 0.005, respectively). However, among the schoolboys (6-11 years old), anxiety was associated only with the cortisol concentration (P < 0.01).

CONCLUSION

Hormonal responses to preoperative emotional stress in preschool boys differ from those in schoolboys.

Ephedrine-induced increases in arterial blood pressure accelerate regression of epidural block

We investigated the hypothesis that ephedrine-induced increases in blood pressure accelerate the regression of epidural block. In patients undergoing minor gynecologic surgery, we performed lumbar epidural blockade using 2% lidocaine containing 1:200,000 epinephrine to which was added 0.1 mg of fentanyl. Eighty minutes after the epidural injection, we started an ephedrine infusion to increase the systolic blood pressure by 20% in 10 min and maintained the value for the following 20 min. Then we compared the proximal extent of sensory analgesia at 80 min with that at 140 min. Ephedrine significantly (P = 0.001) hastened the regression of sensory analgesia. We conclude that an ephedrine-induced blood pressure increase accelerates regression of epidural blockade.

[Effect of dopamine administration on ICG-disappearance rate during prone position anesthesia]

We evaluated the effect of dopamine administration (3 micrograms.kg-1.min-1) on ICG-disappearance rate during prone position in 10 patients undergoing elective spinal cord surgery. Anesthesia was maintained with isoflurane and 50% nitrous oxide in oxygen. ICG-disappearance rate was determined at 3 points, i.e., the day before surgery, during prone position and during the administration of dopamine. Systolic arterial pressure showed no significant difference before and during dopamine administration. ICG-disappearance rate during prone position was significantly lower than the preoperative value. However, ICG-disappearance rate showed no significant difference during dopamine administration and preoperative period. We conclude that dopamine administration may attenuate the depressant effect of the prone position on the hepatic blood flow.

[ICG-disappearance rate during sevoflurane- or neurolept anesthesia]

We evaluated the effect of sevoflurane or neuroleptanesthesia on ICG-disappearance rate in 22 patients undergoing elective extra-abdominal surgery. We divided the patients into three groups, i.e., SN-group (n = 8), SH-group (n = 8) and NLA-group (n = 6). Systolic arterial pressure (SAP) in the patients of SN-group or SH-group was maintained with sevoflurane at about 100% or 70% of the preoperative value respectively. There was no significant difference in SAP between SN-group and NLA-group. In SN-group and NLA-group, there was no significant difference in the ICG-disappearance rate between the values during anesthesia and those during preoperative period. In SH-group, however, it was significantly lower than the preoperative value. We conclude that, when normal systolic arterial pressure can be maintained, sevoflurane or neuroleptanesthesia has little effect on the liver function and hepatic blood flow. Sevoflurane anesthesia with 70% of preoperative SAP, however, may depress the liver function and hepatic blood flow.

Lidocaine inhibits priming and protein tyrosine phosphorylation of human peripheral neutrophils

The addition of agents, such as tumor necrosis factor-alpha, to human peripheral neutrophils (HPPMN) induces priming, which enhances the receptor-mediated superoxide (O2-) generation and tyrosine phosphorylation of several HPPMN proteins. Lidocaine, a local anesthetic, inhibited both enhanced O2- generation and tyrosine phosphorylation of a 115 kDa protein in a concentration- and time-dependent manner. Lidocaine also inhibited protein kinase C sensitive O2- generation induced by phorbol myristate acetate, but not time dependently. Furthermore, lidocaine inhibited O2- generation by non-primed HPPMN induced by formylmethionyl-leucyl-phenylalanine, but this inhibition needed a higher concentration of lidocaine compared with that of primed HPPMN. These results suggest that lidocaine inhibits the priming step of neutrophil activation and that it is linked to the inhibition of tyrosine phosphorylation of a 115 kDa protein.

Effect of gentle massage on regression of sensory analgesia during epidural block

We investigated the effect of gentle epigastric massage on the regression of the sensory analgesia of epidural block. Sixteen patients, who underwent minor obstetric or gynecologic surgery under epidural block with lidocaine, were divided into two groups. Group A was the control group. Group B received gentle massage of the epigastric area for 30 min. The proximal extent of sensory analgesia before massage and 0 and 30 min after the massage was T9 +/- 1, T10 +/- 1, and T10 +/- 1 in group A, and T9 +/- 1, T11 +/- 1 and L1 +/- 1 in group B (mean +/- SD), respectively. The regression of sensory analgesia in group B was significantly (P < 0.001) faster than in group A 30 min after the massage. We conclude that peripheral sensory stimulation as weak as gentle massage may initiate a series of indirect mechanisms that lead to accelerated regression of sensory analgesia.

[Effect of deliberate hypotension with PGE1 on PaO2 in pediatric patients]

We compared the effect of deliberate hypotension with PGE1 on PaO2 between pediatric and adult patients. Seven children, aged 3-9 yrs and 10 adults, aged 35-65 yrs who were scheduled for elective head and neck surgeries were studied. Anesthesia was maintained with enflurane, 50% N2O in oxygen and supplemental infusion of fentanyl. Ventilation was controlled to maintain PaCO2 at 35-40 mmHg. Hypotension was induced with continuous infusion of PGE1 and the systolic blood pressure was maintained at 70% of the presurgical value. Blood gases were measured three times, i.e. before, during, and after hypotension. The hypotension in adults caused a significant reduction in PaO2. In children, on the contrary, PaO2 was not affected by the hypotension. The results suggest that intrapulmonary shunting is smaller in children than in adults during PGE1-induced hypotension.

Modification of intravenous lidocaine-induced convulsions by epinephrine in rats

We studied intravenous lidocaine-induced convulsions in rats to determine whether added epinephrine influences the provocation of lidocaine toxicity. Wistar rats (200-250 g) were divided into three groups of ten, depending on the concentration of epinephrine added to lidocaine. Group 1: plain 1.5% lidocaine; Group 2: 1.5% lidocaine with 1:200,000 epinephrine; Group 3: 1.5% lidocaine with 1:100,000 epinephrine. After surgical preparation and recovery from anaesthesia, all rats received a continuous i.v. infusion of lidocaine (15 mg.ml-1) at a rate of 4.0 mg.kg-1 x min-1 until generalized convulsions occurred. The epinephrine-treated animals developed acute hypertension after one minute of lidocaine infusion (105 +/- 2 to 141 +/- 2 mmHg in Group 2 and 103 +/- 2 to 151 +/- 2 mmHg in Group 3). The PaO2 values in the epinephrine groups at the onset of convulsions were decreased significantly (88.3 +/- 1.0 to 84.0 +/- 1.5 mmHg in Group 2 P < 0.05 and 86.9 +/- 1.2 to 78.1 +/- 2.4 mmHg in Group 3 P < 0.01). However, these values were still within physiological ranges. Serum potassium concentrations in all groups were decreased P < 0.05, (4.24 +/- 0.09 to 3.52 +/- 0.12 mEq.L-1 in Group 1, 4.02 +/- 0.09 to 3.63 +/- 0.17 mEq.L-1 in Group 2, and 4.15 +/- 0.10 to 3.69 +/- 0.17 mEq.L-1 in Group 3).(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of the prone position on ICG excretion during normotensive or hypotensive isoflurane anesthesia]

We evaluated the effect of prone position on ICG excretion during normotensive and hypotensive isoflurane anesthesia. In supine position, either normotensive or hypotensive anesthesia produced no significant prolongation in ICG excretion. In prone position, however, both normotensive and hypotensive anesthesia caused a significant prolongation in the excretion. The results suggest that prone position decreases the hepatic blood flow or hepatic function during isoflurane anesthesia.

[Perioperative blood glucose levels in children]

The perioperative blood glucose (BG) level may represent autonomic responses to various stresses by anesthesia and surgery. We studied the effects of regional blocks combined with general anesthesia on the BG response in pediatric patients. We could not find any significant differences in BG levels between blocked and non-blocked patients. However, BG levels of the children who had been hysterical or crying during the induction of anesthesia were significantly higher than those of the children who had been calm or sleeping. Forty healthy children, aged 1-3 yrs who were scheduled for elective urological surgery were studied. Anesthesia was induced with halothane in oxygen. The anesthesiologist recorded the children's attitude before and during the induction of anesthesia, and described as "calm or asleep (Calm-group), and hysterical or crying (Crying-group)". Patients were assigned randomly to two groups as follow; Group A (n = 20): receiving nerve blocks, Group B (n = 20): without the blocks. The anesthesia was maintained with 1-2.5% halothane in oxygen required to maintain the hemodynamic parameters within 10% of baseline value before surgery. Both groups received lactated-Ringer's solution during the study period. The venous BG levels were determined 5 times, i.e. immediately after asleep, 5, 15, 30 minutes after skin incision and at the conclusion of surgery. BG levels were compared between groups using Mann-Whitney Test. There was no significant difference in BG levels between Group A and B throughout the study period. But BG values of Crying-group (n = 9) were significantly higher than those of Calm-group (n = 31) during perioperative period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenaline absorption: effect of pH in mepivacaine and bupivacaine solutions. A clinical study during halothane anesthesia

The effect of the pH of the solution on the rate of absorption into the blood stream of locally-injected adrenaline using an adrenaline solution mixed with either mepivacaine or bupivacaine was investigated. Forty patients undergoing elective craniotomy received one of the following five solutions for subcutaneous and subgaleaic injection in the dose 0.5 ml/kg: 1) mepivacaine-adrenaline (pH = 6.1), 2) mepivacaine-adrenaline (pH = 7.5), 3) bupivacaine-adrenaline (pH = 6.1), 4) bupivacaine-adrenaline (pH = 7.4), or 5) adrenaline (pH = 6.1). Both mepivacaine and bupivacaine added to the adrenaline solution increased the plasma concentration of adrenaline. Alkalinization attenuated the peak concentration of adrenaline in the case of a mepivacaine-adrenaline solution, but not in the case of a bupivacaine-adrenaline solution.

Role of afferent neural input in regression of sensory paralysis during epidural analgesia

This study was designed to determine the role of the afferent peripheral neural input in the regression of sensory analgesia during epidural analgesia. Eighteen patients who underwent minor obstetric or gynecologic surgery under lumbar epidural analgesia with lidocaine were divided into three groups. Group A received electrical single twitch stimulation at the spinal nerve dermatome one segment rostrad of the proximal extent of sensory paralysis. Group B received electrical twitch stimulation at the anterior crural region where nerve block may have been most profound in this study. Group C was assigned as a control and did not receive any stimulation. The patients received the stimulation for 60 min (i.e., from 80 to 140 min after the epidural injection). The range of sensory analgesia at 140 min was compared with that at 80 min. The regression of sensory analgesia in group B or C was 1 +/- 0 (mean +/- SD) spinal nerve segments, but in group A it was 5 +/- 1, which was significantly (P less than 0.0025) larger than the others. We conclude that the afferent peripheral neural input to a spinal segment where the nerve block is incomplete may accelerate the regression of sensory analgesia from epidural analgesia.

[Effects of lidocaine on stimulation-coupled responses of neutrophils and protein kinase C activity]

The effects of lidocaine on superoxide generation and other stimulation-coupled responses of neutrophils induced by 12-phorbol myristate 13-acetate (PMA) were studied. Depolarization of membrane potential, superoxide generation and chemiluminescence response were inhibited by lidocaine in a concentration dependent manner. Lidocaine inhibited protein kinase C (PKC) activity in a manner competitive with phosphatidylserine. Lidocaine also inhibited the phosphorylation of 47 kDa neutrophil cytoplasmic protein, a phosphorylated protein required for activation of NADPH oxidase. The inhibitory action of lidocaine on PKC activity may correlate with the inhibition of superoxide generation induced by PMA.

[Anesthesia for a patient with Bloom's syndrome]

Bloom's syndrome (BS) is a rare autosomal recessive disorder. The disease is due to chromosome breakage and recombination. The principal features of the syndrome are short stature of prenatal onset, a photosensitive telangiectasic erythema of the face and a marked predisposition to the development of malignant diseases. We are unaware of any previous report of the anesthetic management of a BS patient. In this paper, we reported the anesthetic experience of a male patient (37-yr-old, 26 kg, 136 cm) with Bloom's syndrome who underwent emergency laparotomy. The awake laryngoscopy was carried out, but we could not see the vocal cord directly. The trachea was blindly intubated and anesthesia was induced and maintained with fentanyl, vecuronium and enflurane in 100% oxygen. In a BS patient we should pay attention to potential difficulties with mask fit and laryngoscopy.

Hemodynamic effect of the prone position during anesthesia

We studied 21 patients undergoing lumbar spinal surgery under halothane anesthesia on a convex saddle frame, in order to determine the hemodynamic effect of the prone position. A thermodilution pulmonary arterial catheter was placed in 14 patients (Group PA-1: n = 8; and Group PA-2: n = 6), and an inferior vena caval catheter in the remaining seven patients (Group IVC). Group PA-1 and Group IVC patients were placed in the prone position on a convex saddle frame. In the prone position, the cardiac index (CI) decreased significantly from 3.1 +/- 0.5 to 2.5 +/- 0.3 (l.min-1.m-2, mean +/- s.d., P less than 0.01) without accompanying significant changes in the other hemodynamic variables in Group PA-1. The postural change in Group IVC did not exert a significant effect on the inferior vena caval pressure. Group PA-2 were initially placed in the flat prone position on a flat saddle frame, which produced no significant changes in the hemodynamic variables. Then the convex curvature of the frame was adjusted to the grade appropriate for surgery, which produced a significant reduction in CI (from 2.9 +/- 0.3 to 2.4 +/- 0.4, P less than 0.05). We conclude that the prone position itself may not interfere with the circulatory function. The prone position using a convex saddle frame causes significant reductions in CI, but little change in the other hemodynamic variables.

[TDM (therapeutic drug monitoring) for dosing theophylline]

In order to maximize the effectiveness and safety of drug therapy, it is important to individualize the dosage of potent drugs. Some drugs can not be titrated against the intensity of the therapeutic or toxic actions. Determination of the blood concentration of such drugs can be a helpful guide in adjusting the dosage during their therapeutic use. The drug dosing guided by pharmacokinetics is called TDM or therapeutic drug monitoring. In conventional pharmacokinetics, a large number of blood samples are collected from one patient to determine the individual pharmacokinetic parameters. In TDM, the pharmacokinetic parameters obtained from a group of patients who belong to a certain category are used to guide estimation of the individual pharmacokinetic parameters and only a few blood samples from one patient are sufficient to determine the individual parameters. The blood concentration of a drug and the intensity of its pharmacodynamic action, however, is not necessarily correlated. Therapeutic decisions should never be based solely on the blood concentration of a drug.

[The CO2 absorption capacity and color indication of a newly developed soda lime (Wakolime)]

The CO2 absorption capacity and the color change of ethyl violet (color indicator) of Wakolime A (newer type). Wakolime (older type), and Sorb 800 were studied under the clinical anesthetic condition. A two chamber canister was filled with soda lime and anesthetic gas flowed upward through the canister at the rate of 4 ml.min-1. The wall temperature of each chamber was measured with surface temperature sensing device. After 30 hours of use, the colored soda lime in the first chamber was examined with a color analyzer. The change of wall temperature indicated that the CO2 absorption capacity of Sorb 800 was the largest and that of Wakolime was the smallest among the three. The indicator color of both Wakolime A and Sorb 800 was clearer and of more vivid violet than that of Wakolime, which was dull and grayish. These results indicated that Wakolime A is superior in the CO2 absorption capacity and color indication to Wakolime.

[Effect of lidocaine-epinephrine-dextran solution on the plasma epinephrine concentration during spinal surgery--how to avoid circulatory complications due to the use of epinephrine for hemostasis]

Epinephrine infiltrated for hemostasis may cause adverse effect on the circulatory system and the effect can be potentiated by surgical stimulation. Local infiltration of lidocaine-epinephrine-dextran solution (LED) at the surgical site is advantageous for this purpose since nerve blocking action of lidocaine attenuates surgical stimulation and dextran suppresses the transfer of injected epinephrine to the blood stream, thereby reducing the adverse effect of epinephrine. LED, however, could be injected accidentally into vessels. This is one of the important causes of raising the plasma epinephrine concentration to a dangerous level. The author believes that the following maneuvers are helpful to avoid the rise of plasma epinephrine concentration to a dangerous level; 1) injecting not more than 0.05 ml.kg-1 at a time, 2) monitoring the arterial pressure waves and ECG during the injection by use of a continuous recording device, and 3) halting the injection immediately whenever sudden changes in the arterial pressure and in the height of the T wave in ECG were observed. More importantly, surgeon's cooperation is essential for anesthesiologists to execute these maneuvers.

[The hemodynamic and metabolic changes following tourniquet release during halothane anesthesia]

We measured the hemodynamic and metabolic changes following the release of lower limb tourniquet during halothane anesthesia, and discussed the cause of reduction in the blood pressure and the effective method for prevention. Cardiac index decreased transiently following the release, and gradually increased afterward. Systemic vascular resistance index decreased continuously and progressively until 10 minutes after the release. These results indicate that the causative factors of reduction in the blood pressure are temporary decrease in cardiac output and subsequent decrease in systemic vascular resistance. In mixed venous blood, pH decreased, PCO2 increased and HCO3- remained unchanged after the release. It seems that pH reduction was chiefly caused by the increase in PO2. Thus, the preventive method for reduction in the blood pressure following the tourniquet release may be as follows; 1) intravenous fluid loading, 2) hyperventilation, 3) elevation of lower limb, 4) lightning the anesthesia, and 5) finally giving vasopressors.

[Determination of fentanyl concentrations in the blood with the application of high performance liquid chromatography]

We developed a method to determine the blood concentration of fentanyl by using reverse phase partition liquid chromatography. The extract rate of fentanyl from blood 10 ml was 79 +/- 2%, and the minimum detective concentration of fentanyl was 158 pg.ml-1. These performances are sufficient to determine the blood concentration of fentanyl in clinical anesthesia.

[Effect of nitroglycerin and nicardipine on ICG excretion during halothane anesthesia]

We evaluated the effect of nitroglycerin and nicardipine on ICG excretion during halothane anesthesia in man. Induced hypotension with nitroglycerin during halothane anesthesia produced a significant prolongation in ICG excretion. No such significant prolongation occurred in the patients who received nicardipine. The results suggest that a reduction in hepatic blood flow during anesthesia may be much less in patients who receive halothane with nicardipine than in those who receive halothane with nitroglycerin.

[Convenient and useful computer software for the anesthesiologist]

Convenient and useful computer software for the anesthesiologist to draw figures for presentation, or to perform statistical analysis were presented. Each software is selected in the condition that it does not need special optional hardware, and processes the data quickly even with an old type computer, and also that even a computer beginner can easily operate it. The presented software are as follows: 1) Silhouette (drawing figures), 2) NEO (drawing figures), 3) Graph note (drawing figures), 4) Chart up science (drawing figures), 5) Z's word JG (making slide manuscripts) and 6) Biostat (doing statistical analysis).