The Effect of Adrenaline on the Blockade of Compound Action Potential by Local Anesthetics in Rat Sciatic Nerves / 대한마취과학회지

BACKGROUND: Adrenaline has often been used to prolong the local anesthetic effect during surgical procedures. As a possible explanation for this, a local vasoconstriction caused by adrenaline has been proposed. However, in a recent study, clonidine, an alpha2 adrenergic receptor agonist, was reported to block the conduction of mammalian nerves in vitro. Thus, there is a possibility that adrenaline may block nerve conduction by acting on the adrenergic receptor. The present study is performed to see : (1) If adrenaline directly affects nerve conduction ; (2) If adrenaline affects conduction blockade caused by local anesthetic. METHODS: Recordings of compound action potentials (CAPs) of A- and C-components were obtained from isolated sciatic nerves of adult male Sprague-Dawley rats. Dose-response curves of lidocaine and adrenaline regarding depression of CAPs were determined. Effects of adrenaline on the lidocaine-induced nerve block was assessed by comparing the effect of lidocaine (3.5x 10 5) with a lidocaine-epinephrine mixture (Lido-Epi, 3.5 x10 5 lidocaine with 1:100,000 epinephrine). RESULTS: Adrenaline, near the clinical concentrations, had no effect on the size of either A- or C-component of CAPs. The ED50 of lidocaine was 3.5x 10 5. Lidocaine depressed A-CAP 45.9+/- 7.0 when compared with baseline value, and the Lido-Epi solution depressed A-CAP to 41.7+/- 5.0 (P > 0.05). Lidocaine depressed C-CAP 59.8 +/- 3.4 when compared with the baseline value, and the Lido-Epi solution depressed C-CAP to 60.5 8.1 (P > 0.05). Consequently, adrenaline did not augment lidocaine induced nerve blockade. CONCLUSION: This study confirmed that adrenaline applied to the peripheral nerve has no effect either on nerve conduction itself or on conduction block produced by lidocaine.

Effect of Additional Lidocaine on the Onset Time of Vecuronium / 대한마취과학회지

BACKGROUND: Local anesthetics have been shown to interact with neuromuscular blockers. Most local anesthetics decrease neuromuscular transmission and potentiate neuromuscular block from muscle relaxants. The purpose of this study was to examine the effectiveness of lidocaine on the onset time of vecuronium and to compare that with other method such as simply increasing the dose of vecuronium. METHODS: Sixty patients of ASA physical status I or II were induced with thiopental (4-5 mg/kg) and maintained with O2-enflurane (2.5 vol%). They were randomly divided into four groups: Vecuronium (0.1 mg/kg) was administered intravenously in Group C (n = 15), additional lidocaine (1 mg/kg) was given intravenously 1 min prior to administration of vecuronium in Group L (n = 15), increased vecuronium (0.15 mg/kg) was given in Group V (n = 15) and succinylcholine was given in Group S (n = 15), respectively. Neuromuscular blockade was assessed by train-of-four (TOF) at the adductor pollicis muscle with supramaximal stimulation of ulnar nerve (2 Hz, 0.2 ms) every 12 sec. Endotracheal intubation was performed and intubating conditions were evaluated according to the standard scoring method after measuring the onset time (from the end of giving each muscle relaxants to the 90% suppression of the first twitch). RESULTS: The onset time of Group L (122.0+/-11.0 sec) and that of Group V (98.0+/-16.9 sec) were shorter than that of Group C (135.2+/-16.0 sec) (P<0.05), but these were not shorter than that of Group S (42.0+/-6.2 sec). There was no statistical difference between Group L and Group V. Intubating conditions were good or excellent in all groups. CONCLUSIONS: Additional lidocaine for attenuating sympathetic response could accelerate the onset of vecuronium. But the onset time of this method was not shorter than that of simply increasing the dose of vecuroium nor that of succinylcholine.

Effects of Aminophylline on the Dose-Response Curve of Vecuronium on Rat Hemidiaphragm Preparation / 대한마취과학회지

BACKGROUND: Aminophylline is an inhibitor of phosphodiesterase; it increase the cAMP and, in turn, the level of acetylcholine at the neuromuscular junction. In doing so, it has an antifatigue action. It antagonizes nondepolarizing neuromuscular blockade in animals, and has been anecdotally noted to do so in humans, as well. We investigated the interaction of aminophylline and vecuronium on the dose response curve in vitro. METHODS: Institutional approval was obtained. Thirty seven male Spague Dawley rats (150~200 g) were divided into four groups (control, aminophylline 2.5, 5.0 and 7.5 microgram/ml). The animal were anesthetized with 40 mg/kg phentobarbital. The left hemidiaphragm with phrenic nerve was dissected and mounted within 5 minutes in bath containing 100 ml Krebs solution at 32oC. The phrenic nerve was stimulated at supramaximal intensity by a Grass S88 stimulator through an SIU5 isolation unit. The twitch height was measured by precalibrated Grass FT03 force displacement transducer and recorded. After stabilization of twitch response, vecuronium was added to the solution to obtained an initial concentration 1.0 microgram/ml with aminophylline 0, 2.5, 5.0, or 7.5 microgram/ml. When a stable 3~5 twitch was obtained after first dose, additional vecuronium was added to the Krebs solution in increments of 0.5 microgram/ml to achieve a more than 90% neuromuscular block. The data were analyzed by repeated measures of ANOVA and kappa2 test. RESULTS: There was a significant increase in the effective dose of vecuronium needed to depress the twitch response in aminophylline 5.0 and 7.5 microgram/ml added groups compared with control group and aminophylline 2.5 microgram/ml group. CONCLUSIONS: We conclude that aminophylline shows decreased sensitivity to vecuronium in the phrenic nerve diaphragm preparation of rats.

Endotracheal Intubation through the Intubating LMA / 대한마취과학회지

BACKGROUND: The fundamental responsibility of an anesthesiologist is to maintain adequate ventilation and to supply oxygen in the face of unexpected difficulties with tracheal intubation. The laryngeal mask airway (LMA) has been used as a ventilatory device familiarly for routine or difficult intubation but it has been hard to intubate with it the larger than 6 mm internal diameter (ID) endotracheal tube (ET). The intubating LMA is a new prototype of the LMA; it is partey composed of an anatomically curved rigid airway tube of ID 13 mm for larger ET tube insertion (such as ID 9.0 mm) into a 15 mm connector at its outer end which is fixed permanently to a laryngeal mask. This study was performed to evaluate the technique and facility of the intubating LMA as an apparatus for endotracheal intubation when used by an inexperienced anesthesiologist. METHODS: With informed consent, 43 patients of ASA physical status I or II were selected. Either lubricated polyvinyl chloride or an armored wire tube of ID 7.0 or 7.5 mm was intubated through the No. 4 or 5 intubating LMA. During this procedure, we observed the technical method and success rate, and recorded systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) changes. 24 hours after each operation, we observed subjective symptoms such as sore throat, hoarseness, and difficult in swallowing. RESULTS: The success rate of intubating LMA insertion was as follows: 33 (77%) patients were successed on first attempt, 6 (14%) patients on second attempt, 4 (9%) patients on third attempt. The insertion of the intubating LMA was carried out facilely without another maneuver such as neck extension or tongue expulsion. The success rate of tracheal intubation was 86.1%. In 32 (74.5%) patients there was easy intubation, but 5 (11.6%) patients required more adjustment and the failure rate with them was 6 (13.9%). SBP, DBP were only increased by endotracheal intubation through the intubating LMA, but HR was significantly increased during both insertion and intubation (p < 0.05). Postoperative sore throat was complained of in 11 patients; hoarseness in 1 patient. CONCLUSIONS: Insertion of the intubating LMA is facile due to the absence of need for the maneuvers of neck motion or tongue expulsion. The intubating technique through the intubating LMA is a relatively rapid and easy method, but it requires technical experience which in some cases is lacking in inexperienced anesthesiologists.

Endotracheal Intubation through the Intubating LMA / 대한마취과학회지

BACKGROUND: The fundamental responsibility of an anesthesiologist is to maintain adequate ventilation and to supply oxygen in the face of unexpected difficulties with tracheal intubation. The laryngeal mask airway (LMA) has been used as a ventilatory device familiarly for routine or difficult intubation but it has been hard to intubate with it the larger than 6 mm internal diameter (ID) endotracheal tube (ET). The intubating LMA is a new prototype of the LMA; it is partey composed of an anatomically curved rigid airway tube of ID 13 mm for larger ET tube insertion (such as ID 9.0 mm) into a 15 mm connector at its outer end which is fixed permanently to a laryngeal mask. This study was performed to evaluate the technique and facility of the intubating LMA as an apparatus for endotracheal intubation when used by an inexperienced anesthesiologist. METHODS: With informed consent, 43 patients of ASA physical status I or II were selected. Either lubricated polyvinyl chloride or an armored wire tube of ID 7.0 or 7.5 mm was intubated through the No. 4 or 5 intubating LMA. During this procedure, we observed the technical method and success rate, and recorded systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) changes. 24 hours after each operation, we observed subjective symptoms such as sore throat, hoarseness, and difficult in swallowing. RESULTS: The success rate of intubating LMA insertion was as follows: 33 (77%) patients were successed on first attempt, 6 (14%) patients on second attempt, 4 (9%) patients on third attempt. The insertion of the intubating LMA was carried out facilely without another maneuver such as neck extension or tongue expulsion. The success rate of tracheal intubation was 86.1%. In 32 (74.5%) patients there was easy intubation, but 5 (11.6%) patients required more adjustment and the failure rate with them was 6 (13.9%). SBP, DBP were only increased by endotracheal intubation through the intubating LMA, but HR was significantly increased during both insertion and intubation (p < 0.05). Postoperative sore throat was complained of in 11 patients; hoarseness in 1 patient. CONCLUSIONS: Insertion of the intubating LMA is facile due to the absence of need for the maneuvers of neck motion or tongue expulsion. The intubating technique through the intubating LMA is a relatively rapid and easy method, but it requires technical experience which in some cases is lacking in inexperienced anesthesiologists.

Postanesthetic Complications of Outpatient Surgery / 대한마취과학회지

BACKGROUND: Outpatient surgery has grown in many hospitals. This rapid recently been on the increase in ambulatory surgery would not have been possible without the changing role of the anesthesiolosist and the development of new and short-acting anesthetic drugs. Specific care and knowledge are required for outpatient anesthesia. The aim of this study was to review the clinical experiences of postanesthetic patients at the Oneday Surgery Center (OSC). METHODS: We reviewed the 720 records of the recovery unit in OSC and the 620 records of telephone interviewers? after discharge from January to December 1997. The PACU Record contained Aldrete scores and discharge summaies (about such things as vital signs, alertness and orientation, dizziness, nausea and vomiting, pain, the state of the neurovascular system, the ability to ambulate or dress, voiding, oral intake, etc). Records of telephone interviewers? after discharge contained questionnaires about wound status, limitations a activity and other abnormal symptoms relating to feeding, nausea and vomiting, pain, and medications. RESULTS: The most largest percentages of parameters of patients were below 10 years of age; They had undergone general anesthesia in method, and Herniorraphies. All the patients achieved Alderete score of 7 10 on arrival at the First recovery unit (1st RU) in OSC and achieved 10 points within an hour, when they were transfered to the Second recovery unit (Comfortable room). 41 (5.4%) patients suffered from nausea or vomiting in the Recovery unit. One (0.1%) patient had nausea or vomiting and 5 (0.7%) patients had pain at discharge. The mean durations of stay at the 1st RU and Comfortable room were 90 min and 240 min respectively. Records of telephone visits after discharge showed that 30 (4.8%) patients had nausea or vomiting and 27 (4.3%) patients had postoperative pain after discharge. 20 patients (3.2%) had abnormal symptoms (e.g., fever, coughing, dysuria, epistaxis). There were no limitations in activities or feeding. CONCLUSIONS: For the assurance of a rapid and complication-free recovery in the increasings needed ambulatory surgery, much effort is reguired to increase its quality and safety.

Postanesthetic Complications of Outpatient Surgery / 대한마취과학회지

BACKGROUND: Outpatient surgery has grown in many hospitals. This rapid recently been on the increase in ambulatory surgery would not have been possible without the changing role of the anesthesiolosist and the development of new and short-acting anesthetic drugs. Specific care and knowledge are required for outpatient anesthesia. The aim of this study was to review the clinical experiences of postanesthetic patients at the Oneday Surgery Center (OSC). METHODS: We reviewed the 720 records of the recovery unit in OSC and the 620 records of telephone interviewers? after discharge from January to December 1997. The PACU Record contained Aldrete scores and discharge summaies (about such things as vital signs, alertness and orientation, dizziness, nausea and vomiting, pain, the state of the neurovascular system, the ability to ambulate or dress, voiding, oral intake, etc). Records of telephone interviewers? after discharge contained questionnaires about wound status, limitations a activity and other abnormal symptoms relating to feeding, nausea and vomiting, pain, and medications. RESULTS: The most largest percentages of parameters of patients were below 10 years of age; They had undergone general anesthesia in method, and Herniorraphies. All the patients achieved Alderete score of 7 10 on arrival at the First recovery unit (1st RU) in OSC and achieved 10 points within an hour, when they were transfered to the Second recovery unit (Comfortable room). 41 (5.4%) patients suffered from nausea or vomiting in the Recovery unit. One (0.1%) patient had nausea or vomiting and 5 (0.7%) patients had pain at discharge. The mean durations of stay at the 1st RU and Comfortable room were 90 min and 240 min respectively. Records of telephone visits after discharge showed that 30 (4.8%) patients had nausea or vomiting and 27 (4.3%) patients had postoperative pain after discharge. 20 patients (3.2%) had abnormal symptoms (e.g., fever, coughing, dysuria, epistaxis). There were no limitations in activities or feeding. CONCLUSIONS: For the assurance of a rapid and complication-free recovery in the increasings needed ambulatory surgery, much effort is reguired to increase its quality and safety.