The head-down tilt(HDT) position infuses changes in cerebral blood flow, intracranial pressure, hemodynamic and respiratory system. This study was performed to evaluate the changes in cerebral blood flow and the onset of autoregulation according to the different degree of HDT.

The subjects were 12 healthy adult female volunteers. They were divided two groups : 10° HDT(group 1) and 15° HDT(group 2). The systolic, diastolic and mean blood pressure, heart rate, end-tidal CO₂ concentration and cerebral blood flow velocity on middle cerebral artery by transcranial Doppler were measured before positioning and 1,2,3,5,7,9,11 minute after positioning.

There was no significant changes in cerebral blood flow velocities statistically according to the HDT under 15 degrees. In group 1, vean arterial blood pressure were increased at 5 minutes and returned to control value at 7 minutes after HDT with statistical significances. Diastolic blood pressure in group 1 were increased at 1 and 2 minutes after HDT with statistical significances. In froup 2, systolic blood pressure were increased at 5,7,9,11 minutes after HDT statistically significantly.

There were no significant changes of cerebral blood flow under less than 15° HDT. But systolic blood pressure were increased with 15° HDT in the healthy adults statistically significantly(p<0.05) not but clinically. So, we suggested that if HDT is required, we should take care of the partients more than 10 minutes after HDT.

Pneumocephalus is a pathologic collection of gas within the cranial cavity. Patients undergoing neurosurgical procedures may be at increased risk for the development of tension paneumocephalus if nitrous oxide(N₂O) is used during a subsequent anesthetic.

Thirty-seven patients undergoing cerebral aneurysm surgery had a computed tomographic scan of the head performed on or after the day of their surgery. 64 scans were examined for the presence of intracranial air. The magnitude of pneumocephalus was recorded as A-P(mm), width(m),& numbers of section.

Air was seen in all scans obtained in the first three postoperative days, During the second postoperative weeks, the incidence and the size of pneumocephalus decreased. A significant number of patients have an intracranial air collection in the first two weeks after the procedure.

These data indicate that all patients have pneumocephalus immediately after a cerebral aneurysm surgery. This information should be considered in the evaluation of the patient and the selection of anesthetic agents during a second anesthetic in the first 2 weeks after the first procedure.

Axillary block is a common anesthetic technique for operation on the hand and forearm. Many variations of the axillary approach have been described. Therefore we studied the results obtained when the axillary approach to brachial plexus blockade is attempted utilizing peripheral nerve stimulation(PNS).

Axillary brachial plexus block with PNS(0.5mA, 2Hz) was used in 30 adult patients undergoing hand and forearm surgery. 20ml of 1.5% lidocaine and 20ml of 0.375% bupivacaine solution was injected. A pin prick test was performed at 5, 10, 15, 20, 25 and 30 min. and quality of the clock in the distribution of 7 peripheral nerve of the brachial plexs was evaluated.

Block were 28 cases(93.3%) including 6 cases(20%) of incomplete block and total failure were 2 cases. Average number of blocked peripheral nerve of upper extrmity was 4.4±1.7. The order of rate of block was medial cutaneous n. of forearm, ulnar n., medial cutaneous n. of arm, median n., radial n., musculocutaneous n. and axillary n..

We found that a PNS can be utilized to establish blockade of the upper extrimity, but the success rate is not different than other methods, But it is appropriate for blocks established by beginner without complication.

There are controversies about the analgesic effects of intraaarticular morphine and local anethetics bupivacaine. This study sought to compare the effects of saline with mor-phine, bupivacaine with or without epinephrine, administrated intraarticularly upon pos-toperative pan following arthroscopic knee surgery under general anesthesia.

In a double-blined, randommized manner, 40 patients received one of saline(20ml, n=10), morphine(1mg in 20ml NaCl, n=10), bupivacaine(0.25%, 20ml, n=10), bu-pivacaine with epinephrine(0.25%, 20ml, 200ug of epinephrine, n=10) intaarticularly at the completion of surgery. The pain scores by VAS were determined after 1,2,3,4 and 24 hours after intraarticular administration.

There were no significant statistical differences between four groups in the pain score. The maximal pain scores were 37.5 in control group, 48.0 in morphine group, 33.6 in bupivacaine group postoperative 1 hour and 32.9 in bupivacaine with epinephrine group pos-toperative 2 hours. The pain scores were decreased as the time went by and were minimin as 21.4 in control group, 17.6 in morphine group, 11.2 in bupivacaine group and 12.3 in bu-pivacaine with epinephrine group 24 hour postoperatively.

Though there were no significant statistical significances with those doses, there were tendencies that the bupivacaine group with or without epinephrine had the postoperative analgesic effect rather than control group, and morphine group had a slow onset of analgesic ef-fect. So, we should study to decide the dose or volume of the drugs and appropriate time to evaluate for the anagesic effects after knee arthroscopy further.

Spectral analysis of heart rate variability(HRV) resulted in a characteristic power spectrum with two main regions, a high frequency at 0.15-0.5Hz(HFP) corresponding to the parasympathetic system and a low frequency at 0.017-0.l5Hz(LFP) corresponding to both parasympathetic and sympathetic influences. The ratio of low : high frequency(LFP/HFP) has been postulated as an index of sympathetic activation. We propose that the LFP/HFP ratio will provide important information concerning autonomic nervous system activity during spinal anesthesia especially geriatric patients.

LFP, HFP and LFP/HFP were checked in 30 patients at the baseline and 5, 10, 15, 20, 25 and 30 minutes after subarachnoidal block. We divided patients into two groups: group 1 is 15 patients under 60 years old and group 2 is 15 patients over 65 years old, and we compared those parameters in both groups.

Spinal anesthesia did produce a significant decrease in LFP and HFP in both groups. But sympathetic-parasympathetic balance(LFP/HFP) increased at 5 minutes after spinal block. In group 1, LFP/HFP decreased at 10 minutes after spinal block, thereafter increased gradually. In group 2, LFP/HFP decreased at 10, 15 and 20 minutes and increased at 25 and 30 minutes after spinal block.

These data suggest that autonomic tone decreased with spinal anesthesia and sympathetic-parasympathetic balance decreased for a long time in geriatric patients.

Preoxygenation is recommended in order to prevent hypoxemia with hypoventilation or apnea during induction of anesthesia. The purpose of this study was to determine the duration of preoxygenation required to achieve an end-tidal oxygen fraction(FE'O₂) of 0.9 in children and adults.

In 24 healthy children and adults breathing 100% oxygen, end tidal oxygen and carbon dioxide concentration have been measured at 15 seconds interval from the start of liter per minute. The gas sampling line of the Capnomac II(Datex, Helsinki, Finland) was placed in the nasal cavity.

The study showed that all children attained an FE'O₂ of 0.9 within 75s of preoxygenation, but adults had not reached an FE'O₂ of 0.9 within 180s.

More oxygen wash-in would be expected in children. We suggested that at least 3 min of preoxygenation should be performed before intravenous induction of anesthesia in children.