Control of anesthesia requires the determination of quantities assessing the depth or adequacy of anesthesia. The well-known scheme of Guedel for assessing depth of ether anesthesia is not valid when applied to techniques using neuromuscular blocking agents, opiods and other intravenous anesthetic agents.
Pharmacokinetics and pharmacodynamivs constitute the clinical pharmacological framework within which the time course of i.v. anesthetic drug action in man has been investigated in the past. The common understanding is that virtually all i.v. anesthetics obey linear pharmacokinetics if used in the therapeutic range. Common to all anesthetic agents is their ability to induce EEG frequency slowing. Median EEG frequency has been used to quantitate such slowing. It is shown that median EEG frequency is concentration dependent and is a sigmoid function of drug concentration. In addition median EEG frequency correlates with clinical signs of anesthesia. The interval between 2-3Hz has been identified as that range which minimizes the probability of occurrence of signs of undue light or deep levels of anesthesia. On the basis of these findings i.v. drug delivery devices have been developed for the computer assisted titration of intravenous anesthesia using the pharmacokinetic model of the drug while EEG monitoring is suggested as a noninvasive approach to the therapeutic monitoring of anesthetic drug action.
In most recent times the combined use of computer assisted drug delivery and EEG monitoring was further developed to a closed-loop feedback control system for i.v. anesthetic drug delivery. Such system has been applied to the delivery of methohexitone and propofol in total intravenous anesthesia in volunteers and surgical patients as well as to anesthetic techniques using alfentanil and nitrous oxide. In clinical research such feedback systems allow for an efficient investigation of dose-effect relationships in that they inverse the common approach of such investigations. Instead of giving a dose and observing the emerging effects a feedback systems allows to fix a desired effect and to observe the dose necessary to obtain and maintain this action.

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Removal rate and hemolysis were evaluated during use of a leukocyte removal filter, RC-100, under conditions of massive and rapid blood transfusion.
The filtration procedure was performed under 3 conditions: gravity infusion, pumping at a constant pressure of 150mmHg using a pressure infuser, and sucking and pumping with a plastic syringe. For all procedures, we processed 4 units through the same filter.
Blood samples were taken before and after filtration and WBC count, plasma hemoglobin, and screen filtration pressures were measured.
Both in gravity infusion and the pressured pumping infusion leukocyte removal rate was more than 99.3% after 4 units filtration, but in the sucking and pumping infusion it was 96.6%.
In addition, plasma-free hemoglobin was greater in the sucking and pumping-in infusion, which was related to increasing filtrated units.
In conclusion, sucking and pumping-in infusion for rapid, massive blood transfusion using leukocyte removal filters should not be conducted to avoid hemolysis and inefficacy in leukocyte removal.

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The author measured the margin of safety (MS) in positioning disposable doublelumen endotracheal tubes (DLT) in Japanese adults. MS in posittoning left and right sided DLT was defined as the length of the left mainstem bronchus (LL) minus the length from the proximal margin of the left cuff to left lumen tip (DL), and the length of the right mainstem bronchus (LR) minus the length of the right cuff (DR), respectively, as being described by Benumof and others. Remaining negative value MS indicated it would not be possible to position DLT without some degree of upper lobe obstruction. The incidence of negative value MS was associated with the manufacturers and the size of DLT (27% at MAX). As DLT size decreased, however, MS did not increase except in some cases. Even if using DLT of the same manufacturer and same size, MS was different because of the variations of DL and DR Since the incidence of negative value MS in positioning right-sided DLT is greater than that in positioning left-sided DLT, left-sided DLT should be used whenever possible. Before intubating DLT, not only LL and LR but also DL or DR should be measured, and MS should be confirmed to be enough or not.

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Hypotension frequently occurse in aged patients during epidural block because of sympathetic block and cardiac depression by relatively high volumes of local anesthetic solutions.
We compared the changes in heart rate and systolic blood pressure between aged patients who underwent thoratic epidural block with 2% (0.1ml/kg), 4% (0.05 ml/kg) and 6% (0.05ml/kg) of lidocaine. Decrease in systolic blood pressure was significant in the 2% group during every 5 minutes until 60 minutes, while it was stable in the 6% group.
The pharmacokinetic study of 6% lidocaine (0.1ml/kg) was done in 63 surgical patients who underwent cervical, thoratic and lumbar epidural anesthesia.
The highest Cmax (7.6±1.3/ml) was seen in cervical epidural anesthesia, while the shortest Tmax (8.8±2.0min) and the largest Ka was recognized in lumbar epidural anesthesia. We concluded that a small volume of 6% lidocaine is safe and useful in epidural anesthesia for aged patients.

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Intraoperative hemodynamics and incidence of perioperative myocardial infarction (PMI) were retrospectively studied in 69 operations in 56 patients who had prior coronary artery bypass grafting (CABG group), 17 operations in 15 patients who had prior percutaneous transluminal coronary angioplasty (PTCA group) and 144 opera-tions in 99 patients with definite coronary artery disease (CAD) who had neither CABG nor PTCA (NoTx group). Intraoperative hypotension occurred significantly in the CABG and PTCA group compared to the NoTx group (p<0.01, respectively), while intraoperative hypertension occurred only in the NoTx group (p<0.01). The incidence of arrhythmia in the CABG group was significantly low (p<0.01), compared to that in the NoTx group. There were three PMI (2.1%) only in the NoTx group, but the incidence of PMI was not significant compared to the other two groups. All three patients who had PMI had periods of hypotension during anesthesia. Mortality of coronary revascularization, especially CABG, should be considered when coronary revascularization precedes non-cardiac surgery in patients with severe CAD.

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The effect of preanesthetic famotidine on gastric fluid pH and volume in 28 women undergoing elective radical mastectomy was studied. All patients were given general anesthesia with epidural anesthesia during surgery. These patients were randomly allocated into four groups. Patients in Group 1 served as control, Group 2 received 20mg of famotidine intramuscularly 60 minutes before induction of anesthesia, Group 3 received 20mg of f amotidine orally at bedtime the night before surgery, and Group 4 received the same dosage orally at the same time and 120 minutes before induction of anesthesia. The incidence of a combination of gastric fluid pH above 3.5 and a volume below 25ml was 71% on induction of anesthesia in Group 1, 100% in Group 2, 86% in Group 3, and 100% in Group 4. The same incidence was 29% at the end of anesthesia in Group 1, 89% in Group 2, 43% in Group 3, and 100% in Group 4. In summary, oral administration of famotidine at bedtime and 120 minutes before induction of anesthesia may be effective in reducing gastric acid production and increasing gastric fluid pH. Intramuscular injection of famotidine may be the best method because the effect of f amotidine is stable and quite dependable.

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We reported on three cases of myocardial damage suspected from ultrasonic cardio-graphy (UCG) following subarachnoid hemorrhage (SAH). In two cases, ECG on admis-sion indicated abnormalities similar to severe myocardial infarction. However, cardiac isoenzymes showed no evidence of acute myocardial infarction. The degree of hypo-kinesis on UCG was parallel with the abnormal findings on ECG. Cardiac function recovered by the 9th and 15th day respectively. The ECG in the third case was normal but the UCG showed deterioration of cardiac functions. Induction of anesthesia was very difficult due to heart failure.
Cardiac dysfunction associated with cerebrovascular disease has been believed to be reversible. Recent studies have demonstrated that focal myocytolysis after SAH may cause severe myocardial damage. UCG is more sensitive than ECG in detecting cardiac dysfunction caused by SAH, and UCG monitoring is recommended for safe perioper-ative management.

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