Dexmedetomidine Sedation in an Old Patient for Revision Total Hip Arthroplasty

A revision total hip arthroplasty (THA) that anticipated massive bleeding and the need for blood transfusion was scheduled. The patient was a 73-year-old man who had well controlled hypertension. A combined spinal and epidural anesthesia was performed. Dexmedetomidine was administered from the beginning of the arterial and central line catheterization, until the end of the operation. During the 10 hours and 30 minutes surgery, the estimated blood loss was about 7,000 mL, with a total infused red blood cell amount of 14 units, total fresh frozen plasma of 6 units, a total crystalloid of 6,850 mL and of colloid 1,500 mL. The Ramsay sedation score was maintained within 3 and the hemodynamic condition was stable. We found that dexmedetomidine can be safely used for sedation, even during an operation requiring massive transfusions and a prolonged operation time.

Comparison of Changes in Bispectral Index and Auditory Evoked Potential Index during Endotracheal Intubation / 대한마취과학회지

BACKGROUND: Depth of anesthesia monitoring needs a consistent and reliable measure in close to real time. The aim of this study was to compare auditory evoked potential (AEP) as determined using the autoregressive model with exogenous input (ARX-model) versus the bispectral index (BIS) by conventional averaging. The hypothesis of the present study was that since the ARX-model extracts AEP faster than BIS, the former should be able to detect changes during the brief, intense stimulus of endotracheal intubation. METHODS: Forty ASA physical status I or II patients scheduled for orthopaedic surgery were randomly assigned to 2 groups (group 1; BIS and group 2; AEP). Anesthesia was induced with target-controlled infusions of propofol. After the effect-site concentration of propofol was reached at 4 microliterml, vecuronium 0.1 mg/kg was administered. The trachea was intubated 3 min after the administration of vecuronium. AAI and BIS were compared during endotracheal intubation. RESULTS: During endotracheal intubation, the ARX-extracted AEP Index showed a significant increase (P < 0.05), the BIS did not change significantly. There is a significant difference between the ARX-extracted AEP and the BIS, in terms of response time. CONCLUSIONS: The ARX-extracted AEP Index increases during the brief, intense stimulus of endotracheal intubation. For tracing short-term changes at the hypnotic level, ARX-extracted AEP is considered as the more useful monitoring device in terms of a real time measure.

Comparison of Bispectral Index at Each Thiopental Sodium Induction Dose / 대한마취과학회지

BACKGROUND: Thiopental sodium is one of the most commonly used intravenous anesthetics, but there exists no reliable report of BIS that can predict the hypnotic state. Our purpose was to compare BIS values after administering different doses of thiopental sodium. METHODS: With institutional review board approval and informed consent, sixty adult patients scheduled for elective surgery were studied. The patients were divided into three groups according to induction doses as follows: group 1: 3 mg/kg, group 2: 4 mg/kg, group 3: 5 mg/kg. After induction the BIS was monitored at 15 second intervals to 90 seconds. The number of patients with a BIS of less than 55 was recorded. RESULTS: The BIS at baseline and 15 seconds after administration were not statistically different in the three groups. The BIS at 30 seconds in group 1 differed from those of groups 2 and 3, but all of the mean BIS values were more than 55. The BIS values at 45 and 90 seconds were statistically different for three groups, and the mean BIS values of groups 2 and 3 were less than 55. The number of patients with a BIS of less than 55 at any point was eight in group 1, and twenty in groups 2 and 3. CONCLUSIONS: BIS monitoring suggests that a dosage above 4 mg/kg of thiopental sodium is sufficient for the reliable induction of anesthesia.

The Effects of Intraperitoneal CO2 , Insufflation on the Blood pressure , pH and Blood Gases during Laparoscopy / 대한마취과학회지

We studied the effects of intraperitoneal CO2 insufflation on the blood pressure, acid-base balance and blood gas changes by continuous recording of blood pressure, heart rate and repeated determinations of blood pH and blood gas. This was done by direct method in various conditions such as the horizontal position without CO2 insufflation, lithotomy and Trendeledburg positions with CO2 insufflation and the horizontal position after deflation in 20 women having had laparoscopies. The following data are the experimental results. 1) Laparoscopy in 20 women with intraperitoneal CO2 insufflation of up to 10~15 mmHg in the lithotomy and Trendelenburg positions under controlled ventilation was sccompanied with elevated arterial pressure, increased heart rate, increased PCO2, and a decrease in blood pH. 2) When the abdomen was completely deflated and the patient was placed in horizontal position under controlled ventilation, all recordings returned close to the original control values. 3) The present study represented the remarkable stability of the cardiovascular system, acid-base balance and blood gases with the aid of controlled ventilation during CO2 pneumoperitoneum.