Mechanics of artificial ventilation was analyzed with regards to the weight of the lung and of other organs. Consideration of the "weight" revealed the followings:
1. "Low compliance" is considered ordinarily being "hard" or "solid", but it may be caused also by "being heavy".
2. "Weight" is a force, or pressure multiplied by area. Moving or supporting a weight requires pressure, apparantly decreasing the compliance.
3. The lung has its own weight: this pushes the down-lung further down decreasing the compliance of the down-lung. In the supine position, the diaphragm is being pushed and displaced by the abdominal content. These two factors decrease, though nothing to do with elasticity, and flatten the PV-relationship.
5. The spontaneous ventilation, achieved by the increased tension of the diaphragm, ventilates preferentially the down-lung, because it straightens the diaphragm by increasing the internal tension. The artificial ventilation, on the other hand, ventilates according to the pressure differesce. During inspiration, this is higher in the upper part of the lung, achieving preferentially the ventilation of the upper-lung.
6. From such consideration, the pressure-volume curve of the lung-thorax system should be convex downwards, contrary to commonly-believed convex upwards shape. This was supported by the experiment. This explains various notions so far inexplicable.

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The alveolar-arterial O₂ difference (A-a DO₂) decreased at severe metabolic acidosis in the three cyanotic infants.
Case 1. A 47-day-old infant was diagnosed as Tetralogy of Fallot and operated on for a subclavian-pulmonary shunt. The A-a DO₂ decreased from 120mmHg to 81mmHg at severe metabolic acidosis after the surgery.
Case 2. A 9-day-old infant was diagnosed as giant hemangioma in the liver. The A-a DO₂ decreased from 220mmHg to 80mmHg at severe metabolic acidosis after the angiography.
Case 3. A 53-day-old infant was diagnosed as Tetralogy of Fallot and operated on for an aorto-pulmonary shunt. A cardiac arrest occured during the surgery but it was successful in a resuscitation. The A-a DO₂ decreased from 650mmHg to 400mmHg at severe metabolic acidosis after the resuscitation.
The A-a DO₂ could be decreased by the increase of PvO₂, the decrease of the intra cardiac right to left shunt and the improvement of V/Q. On the other hand, it also might be decreased directly by the H⁺ ion. The decrease of pH and the increase of PO₂ were observed at the same time after a little addition of weak HC1 to the other patient's arterial blood.
The A-a DO₂ might be decreased by the right shift of the oxygen dissociation curve.

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Following the caudal epidural administration of lidocaine 10mg/kg, pulmonary arterial pressure, aortic pressure and heart rate were measured before and one year after surgical treatment of heart defects in 7 children with congenital heart disease (ventricular septal defects, patent ductus arteriosus, atrioventricular canal) and pulmonary hypertension. Mean pulmonary arterial pressure was 34mmHg before surgery and increased to 40mmHg 15 minutes after injection of lidocaine. After correction of congenital heart defects, mean pulmonary arterial pressure was 15mmHg and slightly increased after injection. Following the administration of lidocaine, mean aortic pressures were decreased by 6% and 5% respectively before and after surgical treatment of congenital heart defects. Heart rate stayed unchanged after injection.
It is concluded that caudal anesthesia is undesirable in the children with congenital heart disease and pulmonary hypertension, but it is useful for cardiac catheterization in those without pulmonary hypertension.

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We used enflurane for maintenance anesthetic during induced hypothermia in 9 cases of intracranial operations. Anesthesia was induced with thiopental and maintained with enflurane and nitrous oxide. Ventiration was controlled with a respirator. With administration of Triflupromazine 0.78-1.36mg/kg, hypothermia was induced by surface cooling technique. During hypothermia enflurane concentration was maintained between 0.4 and 0.8%. Throughout the course of hypothermic anesthesia there were no severe arrythmias or no metabolic acidosis, and the cotrol of intracranial pressure was satisfactory. We are impressed by the fact that in this method hemodynamics is stable and the return of consciousness takes short time. This method will be usefull for neurosurgical operations of vascular rich tumors.

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Anesthetic management of Progressive Systemic Sclerosis with Paranoia
We report a case of progressive systemic sclerosis (PSS) with paranoia who had undergone gastric resection.
Patients with PSS have many problems for the anesthetist, because they often have multiorgan failures
-Skin (masked face and inability to open the mouth), muscles, bones (sclerodactyly), mucous membranes, heart (scleroderma heart disease resulting from myocardial fibrosis), lungs (lung volume reduction resulting from lung fibrosis), intestinal tract (inadequete alimentation), and other internal organs.
This patient had the skin lesions, sclerodactyly, lung dysfunction and others.
In this case, Continuous epidural anesthesia (1.5% lidocaine) was combined with light general anesthesia (nitrous oxide, oxygen, diazepam and pancuronium)
We had few troubles with this patient before, during and after anesthesia, and besides did not observe the prolongation of regional anesthesia following the administration of lidocaine.

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There are various problems associated with spinal anesthesia such as the fact that the duration of anesthesia is short, as well as complications like hypotension, headache or etc. But we obtained excellent results using bupivacaine in spinal anesthesia, and have reported them here along with the results of comparison with the use of tetracaine.
26 patients scheduled for lower abdominal surgery and orthopedic surgery of lower limb under spinal anesthesia were included. In these patients, sixteen patients were anesthetized with 0.5% bupivacaine and ten patients with 1% tetracaine (hyperbaric solution).
Results: There was no significant difference in the spread of anesthesia in both groups.
In bupivacaine group, no correlation was found between the age of the patients and the spread of anesthesia.
A significant decrease in blood pressure was noticed in the tetracaine group, but, in bupivacaine group, it was stable. The duration of anesthesia showed an average level of 7.2±1.0 hours in the bupivacaine group, which was a significant longer than in the tetracaine group.
Conclusion: 0.5% bupivacaine was used in spinal anesthesia, and excellent anesthetic state were obtained. Regardless of age, hemodynamics was stable, duration of anesthesia long, and complications relatively rare.
We can look forward, therefore, to wide clinical applications of its use in the future.

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Caudal analgesia for surgical procedures was performed on 65 children, newborn to 8 years of age. A 0.25 per cent solution of bupivacaine was used for infants less than 5kg in body weight, 0.5 per cent solution of bupivacaine for larger children.
The segmental dose requirements for caudal analgesia increased with increases in body weight (r=0.97, p<0.001). The resultant regression equation stated that the dose requirements (ml/spinal segment) of bupivacaine were equal to [0.050 x body weight (kg)-0.025]. The mean maximum concentration of bupivacaine were 0.62±0.24 (mean ±S.D.)μg/ml and occurred at 30 and 45 minutes after injection of bupivacaine 3.7mg/kg with epinephrine 1:200, 000. These blood concentrations were measured by venous and whole blood samples. The patients had adequate analgesia for 2.5 hours through the surgical procedures and managed whth incremental intravenous administration of thiamylal 3mg/kg.
The dose requirements of bupivacaine for caudal analgesia in children are less than those of lidocaine calculated previously. I recommend the caudal extradural administration of bupivacaine for long-lasting operation and postoperative pain relief.

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ABM is the new monitor system consisted of measuring systems of EMG, EEG, NMT, expiratory CO₂ and blood pressure and little is known about the reliability of these systems.
So we examined the reliability about EEG and EMG system.
In EEG, we compared the main power spectrum by high speed Fourier analysis with mean frequency using "zero-crossing method." in ABM systems, and induced EMG by Myogram-Type 2000 with responses in neuromuscular transmission module (NMT).
In the results, there existed definite correlations between main power spectrum (x) and mean frequency (y), y=1.01x-0.04 (r=0.88).
Concerning the train of four twich ratio (T₁) and train of four ratio (Tr), we could found good correlation between EMG and NMT,
T₁: y=0.97x+20.3 (r=0.78)
Tr: y=1.0x+14.3 (r=0.97)
x: EMG by Myogram-Type 2000
y: NMT in ABM
From these results, it is concluded that EEG and NMT system in ABM were reliable for clinical use.

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It was speculated that waste sampling gas from CO₂ monitor might be another source of air pollution in the operating room.
We measured N₂O concentrations in the operating room when CO₂ monitor was in use.
In the poorly ventilated room, N₂O concentrations reached near 100ppm due to waste gas from CO₂ monitor.
Thus, the waste gas from CO₂ monitor is another source of air pollution in the operating room, and waste gas should be scavenged.

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