Margin of Safety in Positioning Double-lumen Endotracheal Tubes Using a Fiberoptic Bronchoscope in Korean Adult / 대한마취과학회지

BACKGROUND: The margin of safety is the length of the mainstem bronchi, over which double-lumen endotracheal tubes (DLTs) can be moved and still be correctly positioned. A negative value of margin of safety means that DLTs may not be safe. We measured the length of the left and right mainstem bronchi and margin of safety in Korean adults. METHODS: One hundred and fifty-six ASA I or II adult patients undergoing an elective surgery were examined. After nduction of general anesthesia, we measured the lengths from the upper incisor to the tracheal carina, to the proximal margin of the left and right upper lobe bronchial opening using a fiberoptic bronchoscope. We calculated the lengths of the left and right mainstem bronchi and margin of safety using the measured lengths. RESULTS: In Korean adults, the average margin of safety of left-sided DLTs of males and females was 2.4 +/- 1.0 cm and 1.9 0.7 cm and right-sided DLTs of males and females was 1.0 +/- 0.9 cm and 0.8 +/- 0.3 cm, respectively. The percentage of a negative value of the margin of safety in positioning right-sided DLTs was 10.4% in males and 8.6% in females. However, all values of the margin of safety in left-sided DLTs were positive. CONCLUSIONS: Using left-sided DLTs, regardless of the operative side, is better than right-sided DLTs because left-sided DLTs have a greater margin of safety in positioning. If we use right-sided DLTs, we should confirm the proper position of tubes using a fiberoptic bronchoscope.

The Application of Total Intravenous Anesthesia & Propofol-N2O Anesthesia for Cesarean Section / 대한마취과학회지

BACKGROUND: According to the increasing rate of cesarean section, the efforts of seeking safer and more satisfactory obstetric anesthesia techniques have been continued. Propofol, 2,6 di-isopropyl phenol, is a relatively new intravenous anesthetic agent and has been used for induction and maintenance for total intravenous anesthesia (TIVA). Authors examined the anesthetic technique using following anesthetics combinations; N2O-propofol, fentanyl-propofol, ketamine-propofol and made comparison of these ones for intraoperative hemodynamic stability, maternal and fetal safety. METHODS: Sixty patients (ASA physical status 1 or 2) scheduled for cesarean section were randomly allocated into three groups, group N (propofol-N2O, n=20), group F (propofol-fentanyl, n=20), group K (propofol-ketamine, n=20). We checked the changes of blood pressure and heart rates during operation, anesthetic induction time, neonatal status (Apgar score, umbilical vein blood gas analysis), presence of intraoperative awareness and recovery time. RESULTS: No significant differences in intraoperative hemodynamic changes, induction time and baby status. Total propofol dosages were greater in group N than group K (p<0.05) and maternal recovery time was prolonged in group K than group N or F (p<0.05). CONCLUSIONS: Anesthetic management using propofol-N2O or propofol-fentanyl or propofol-ketamine for cesarean section would provide satisfactory anesthesia without significant adverse effects to both mother and fetus.

The Effects of Endobronchial Insufflation of Air on Cardiopulmonary System in Apneic Dogs / 대한마취과학회지

BACKGREOUND: Mass casualties from organophosphrous inhalation die from respiratory depression. Gas supplies and equipment are limited for mechanical ventilation of multiple subjects. Endobronchial insufflation of air (EIA) requires only a compresssor and airway catheters. We examined clinical usefulness of EIA in a model of apnea produced by tetrodotoxin (TTX) infusion. METHODS: Five anesthetized dogs were applied the conventional mechanical ventilation (CMV) while 12 mcg/kg TTX was infused IV over 90 min to produce apnea. EIA at 1 L/kg/min was delivered through a 35 cm long 0.8 cm I.D. catheter with a forked end placed astride the carina. Measurements of cardiovascular and respiratory function were made after TTX (time=0) on CMV, and then serially for 4 hours of EIA. RESULTS: All dogs survived through 4 hours study. PaO2 decreased significantly within 30 min and then slowly increased significantly after 60 min. PaCO2 increased significantly within 30 min and decreased significantly after 60 min. HR increased significantly after 20 min and MAP increased significantly after 60 min. Mean SD of PaO2, PaCO2, pHa, SaO2, cardiac output, mean pulmonary pressure, mean arterial pressure, systemic vascular resistance, central venous pressure and Qs/Qt are shown in table. Spontaneous respiratory efforts slowly returned after 45 min of EIA and resulted in the improvement of gas exchange. CONCLUSION: EIA is a field ventilatory technique useful when other equipment may not be available. The airway catheter can be placed by cricothyroidotomy. EIA supports life and produces normal survivors in apneic dogs.

The Effect of Lidocaine with Combined Drugs on Onset Time and Duration of Caudal Anesthesia / 대한마취과학회지

BACKGROUND: caudal anesthesia is a safe and reliable technique for surgical anesthesia as well as an alternative to narcotics for postoperative analgesia for procedure below umbilicus. Onset time and duration of local anesthetics had been influenced by local anesthetics with combined drugs. We wanted that the time required for the onset of local anesthesia should be short and long enough to allow time for the contemplated surgery. METHOD: To investigated the effect of lidocaine with combined drugs, 120 ASA physical status I, II patients who underwent perianal surgery with caudal anethesia. The patients were diveded into 5 groups : control group received 1.5% lidocaine 27ml, group I received lidocaine with epinephrine (1:200,000), group II received lidocaine with morphine 2mg, group III received lidocaine with fentanyl 50 g, group IV received lidocaine with clonidine 75 g. We have compared the onset time and duration of analgesia of 5 groups. RESULTS: 1. The onset time of analgesia for pin prick test were not significantly changes between groups. 2. The duration of analgesia was significantly more prolonged in group II(863.8 222.1 min) than other three group I, III, IV. 3. The most common side effect was urinary retention(20 cases, 16.7%) in all groups(n=120). 6 cases(24%) in group II(n=25), 2 cases(8%) in group III(n=25) were complained of pruritus. Bradycardia and hypotension were observed in group IV(n=20) (each 1 cases, 5%). CONCLUSIONS: It is suggested from the above results that the morhine group during caudal anesthesia can produce more prolonged duration of analgesia.

Comparison of Propofol-N2O and Propofol-fentanyl Anesthesia for Outpatient Surgery / 대한마취과학회지

BACKGROUND: The choice of anesthetic agents and adjuvants during outpatient surgery is of critical importance. Propofol is widely used for the induction and maintenance of outpatient anesthesia. Because propofol lacks analgesic properties, very high concentrations may be required when propofol is used as the sole anesthetic drug. Propofol is used with adjuvants such as nitrous oxide or opioid. This study was designed to evaluate the intraoperative hemodynamic response, recovery characteristics and side effects of propofol-fentanyl anesthesia compared with propofol-N2O anesthesia for outpatient surgery. METHODS: Twenty six healthy and unpremedicated patients scheduled for outpatient surgery were randomly allocated to receive either propofol-N2O anesthesia (N-group) or propofol-fentanyl anesthsia (F-group). The patients in N-group were ventilated with nitrous oxide 60~70% in oxygen and the patients in F-group were ventilated with oxygen 40% in nitrogen via laryngeal mask airway (LMA). RESULTS: There was no significant difference in blood pressure during anesthesia, recovery time and side effects between two group. There was significant decrease of heart rate in F-group. CONCLUSION: We concluded that nitrous oxide and fentanyl are reasonable adjuvants of propofol anesthesia in outpatient anesthesia.