The effect of dexmedetomidine on the adjuvant propofol requirement and intraoperative hemodynamics during remifentanil-based anesthesia / 대한마취과학회지

BACKGROUND: The effects of dexmedetomidine on the propofol-sparing effect and intraoperative hemodynamics during remifentanil-based propofol-supplemented anesthesia have not been well investigated. METHODS: Twenty patients undergoing breast surgery were randomly allocated to receive dexmedetomidine (group DEX) or placebo (group C). In the DEX group, dexmedetomidine was loaded (1 microg/kg) before anesthesia induction and was infused (0.6 microg/kg/h) during surgery. Anesthesia was induced with a target-controlled infusion (TCI) of propofol (effect site concentration, Ce; 3 microg/ml) and remifentanil (plasma concentration, Cp, 10 ng/ml). The Ce of TCI-propofol was adjusted to a bispectral index of 45-55, and Cp of TCI-remifentanil was fixed at 10 ng/ml in both groups. Mean arterial blood pressure (MAP) and heart rate (HR) were recorded at baseline (T-control), after the loading of study drugs (T-loading), 3 min after anesthesia induction (T-induction), tracheal intubation (T-trachea), incision (T-incision), 30 min after incision (T-incision30), and at tracheal extubation (T-extubation). MAP% and HR% (MAP and HR vs. T-control) were determined and the propofol infusion rate was calculated. RESULTS: The propofol infusion rate was significantly lower in the DEX group than in group C (63.9 +/- 16.2 vs. 96.4 +/- 10.0 microg/kg/min, respectively; P < 0.001). The changes in MAP% at T-induction, T-trachea and T-incision in group DEX (-10.0 +/- 3.9%, -9.4 +/- 4.6% and -11.2 +/- 6.3%, respectively) were significantly less than those in group C (-27.6 +/- 13.9%, -21.7 +/- 17.1%, and -25.1 +/- 14.1%; P < 0.05, respectively). CONCLUSIONS: Dexmedetomidine reduced the propofol requirement for remifentanil-based anesthesia while producing more stable intraoperative hemodynamics.

Bronchospasm Caused by N-Acetylcysteine Intratracheal Instillation in a Patient with Bronchial Asthma: A Case Report / 대한마취과학회지

We report of a successfully treated case of fatal bronchospasm, which developed after N-acetylcysteine bolus intratracheal instillation in a 49-year-old female patient with bronchial asthma undergoing laparoscopic cholecystectomy. N-acetylcysteine has been widely used as a potent mucolytic agent since 1963, with few reported adverse reactions. Its mucolytic action is due to the breakage of disulfide bonds in mucus mucoproteins. Most adverse reactions to N-acetylcysteine are usually mild and respond to the termination of the medication and symptomatic treatment with antihistamine. However, several cases of fatal bronchospasm have been reported in asthmatic patients after inhaled or intravenous N-acetylcysteine. N-acetylcysteine induced bronchospasm could be avoided in most asthmatic patients if its concentration is not allowed to exceed 10%, and concomitant beta2-selective bronchodilators are utilized. Nevertheless, asthma is still a potent risk factor and requires special precautions, including careful risk-versus-benefit assessment, close observation and the immediate availability of resuscitation equipment and staff in the event of life-threatening bronchospasm.

Rocuronium Onset, Recovery and Effects on Blood Pressure and Heart Rates in Children Under O2- Propofol Anesthesia / 대한마취과학회지

BACKGROUND: Rocuronium(ORG 9426) is a new steroid nondepolarizing neuromuscular blocking drug with fast onset and intermittent duration of action. Its effects on vital signs are controversial. We studied onset, clinical duration, recovery index of rocuronium and its effects on blood pressures and heart rates. METHODS: We selected thirty healthy children who would receive inguinal herniorrhaphy and allocated them to 2 groups(control and rocuronium group). Without premedication or with oral medication of PocralTM (20 mg/kg), they administrated propofol(2.5 mg/kg) intravenous for loss of consciousness and we maintained anesthetic states with 20 mg/kg/hr of propofol. After 2 minutes, we checked BP(SBP/ DBP/MBP) and HR at every minutes and checked TOF, T1 height compare to control, T4 to T1 at every twenty seconds. We injected intravenously rocuronium(0.8 mg/kg, 2ED95) to rocuronium group and nothing to control group. We determined intubation time(from injection to 90% depression of maximal block), onset time(to maximal depression or T1=0), clinical duration(to T1=25%) and recovery index(from T1=25% to T1=75%). RESULTS: In children, intubation time was 93.8sec, onset time was 146.2sec, clinical duration was 34.6min, recovery index was 15.4min. SBP, DBP, MBP and HR were not changed independent of injection of rocuronium. CONCLUSION: Rocuronium is a muscle relaxant with rapid onset and intermittent clinical duration in children. It does not affect BP and HR.

The Analysis on Overtransfusion of Surgical Patients / 대한마취과학회지

BACKGROUND: Although blood is very important therapeutic agent in bleeding patients, it may transmit disease, cause an adverse reaction in the recipients, raise the cost of patient care. Since the misuse and inappropriate use of blood is common, we are to review the transfusion practice in our hospital and to reduce unnecessary blood transfusion. METHODS: During a 10-month period from June 1994 through March 1995, 347 patients received blood transfusion during the operation. Among them, we reviewed retrospectively the charts of 211 patients available. We analyzed the transfusion pattern of 47 patients whose postoperative hematocrit exceeded 32 percent to determine the magnitude and cause of unnecessary blood transfusion. RESULTS: The patients of postoperative hematocrit over 32 percent were 119 patients out of 211 patients(56.4%). The main cause of overtransfusion was no reevaluation of the patients hematocrit after the prior unit was given. CONCLUSIONS: Guidelines for transfusing patients must be constructed based on acceptable intraoperative hematocrits. Unnecessary transfusion can be decreased when the transfusion done according to the guidelines, insisting on each reevaluation of the hematocrit prior to the administration of unit of blood.

The Depth of Double Lumen Endobronchial Tube and the Effect of Lateral Decubitus Position to the Depth in Korean Adult Patients / 대한마취과학회지

BACKGROUND: During one-lung anesthesia in thoracic surgery, accurate placement of double lumen endobronchial tube(DLT) is essential. We have only a few data regarding adequate depth of DLT, especially after position change. We measured the depth of DLT and the change of depth after position change in 50 adult patients. METHODS: After endotracheal intubation with left-sided Robertshaw type polyvinyl chloride(PVC) endobronchial tube, fiberoptic bronchoscope was inserted through tracheal lumen and we positioned the proximal end of the bronchial cuff just below the carinal bifurcation. The depth of the DLT from the upper incisor was recorded, and was rechecked after position change to lateral position. RESULTS: The depth of the DLT was 29.4 +/-1.3 cm(male: 30.2+/- 0.9, female: 28.2+/- 0.8) and this was related with height. But in female group depth of DLT was not related with height. Within the same height group, the depth of DLT differ up to 3.5 cm. The change of depth more than 0.5 cm after position change ocurred in 21 out of 50 patients. CONCLUSION: The adequate depth of DLT in Korean patients, in total patients and in male group seems to related with their height, but in female group the depth of DLT was not related with their height. Within same height group, the depth of DLT may differ greatly. So, the depth of DLT must be adjusted individually. After position change, the head and neck should be kept in neutral position and the adequacy of the depth of DLT must be rechecked.

Effect of Positive End-Expiratory Pressure to the Ventilated Lung during One Lung Anesthesia on the Arterial Oxygenation / 대한마취과학회지

One lung ventilation(OLV) during thoracotomy is frequently used for the purpose of facilitating surgical exposure by collapsing the lung in the operative hemithorax. But severe hypoxemia may occur during OLV inspite of higher inspired oxygen concentration. This study was performed to evaluate the effect of positive end-expiratory pressure(PEEP) level to the ventilated lung on the arterial oxygenation in the thoracotomy patients(n-10) who showed PaO2 below 100 mmHg during one lung ventilation (OLV) at the F1O2 = 1.0 . After measuring control value of arterial blood gas(ABGA), peak inspiratory pressure and hemodynamic parameter (mean arterial pressure and heart rate), PEEP device 5 cmH2O and then 10 cmH2O was applied to the expiratory breathing circuit for 10 min at each pressure setting. Data of above parameter was collected after 10 min each PEEP application. There were no siginificant changes in the mean arterial pressure and heart rate between control, PEEP 5 cmH2O and PEEP 10 cmH2O. Although PaO2 did not significantly increased with PEEP 5 cmH2O compared to control value, the application of PEEP 5cmH2O increased PaO2 in 6 patients and decreased in 4 patients. In the PEEP 10 cmH application, PaO2 was significantly improved compared to control and PEEP 5 cmH2O values (78.4+/-11.6 mmHg, 84.6+/-19.2 mmHg vs. 95.3+/-18.5 mmHg). It is concluded that it may be necessary to adjust PEEP level to the ventilated lung to improve oxygenation when hypoxemia occurs during OLV.