Byung Seop Shin

Neck circumference to thyromental distance ratio: a new predictor of difficult intubation in obese patients

BACKGROUND This study was performed to assess whether intubation is more difficult in obese patients and to assess the ability of a new index: the ratio of the neck circumference to thyromental distance (NC/TM), to predict difficult intubation in obese patients. METHODS The incidence of difficult tracheal intubation in 123 obese (BMI≥27.5 kg m(-2)) and 125 non-obese patients was compared. Difficult intubation was determined using the intubation difficulty scale (IDS≥5). The NC/TM ratio was calculated and its ability to predict difficult intubation in obese patients was compared with that of established predictors including high BMI, the Mallampati score, the Wilson score, NC, width of mouth opening, sternomental distance, TM, and a previous history of difficult intubation. RESULTS Difficult intubation was more frequent in obese patients than in non-obese patients (13.8% vs 4.8%; P=0.016). Multivariate analysis revealed that the Mallampati score, the Wilson score, and NC/TM independently predicted difficult intubation in obese patients. Among these three indices, NC/TM showed the highest sensitivity and a negative predictive value, and largest area under the curve on an ROC curve. CONCLUSIONS Difficult intubation was more common in obese patients and the NC/TM was a better method for predicting difficult intubation than other established indices.

Insulin reverses bupivacaine-induced cardiac depression in dogs

We tested the hypothesis that an insulin infusion would effectively treat bupivacaine-induced cardiac depression in dogs. In 24 mongrel dogs anesthetized with pentobarbital (5 mgkg−1h−1, IV), 0.5% bupivacaine was administrated at a rate of 0.5 mgkg−1min−1 until the mixed venous oxygen saturation decreased to 60% or less. The bupivacaine infusion induced a decrease in mean arterial pressure, cardiac output, and heart rate. The dogs were randomly assigned to one of four groups after the end of bupivacaine infusion. The Control (C, n = 6) and Glucose (G, n = 6) groups received an IV infusion of normal saline (2 mL/kg) and glucose (2 mL/kg of 50% dextrose in water) for 15 min, respectively. The Insulin-Glucose (IG, n = 6) group received an IV bolus of regular insulin (1 U/kg), plus a glucose infusion (2 mL/kg of 50% dextrose in water) for 15 min. The Insulin-Glucose-Potassium (IGK, n = 6) group received the same dose of insulin and glucose as the IG group, plus potassium (1–3 mEqkg−1h−1). Mean arterial pressure, cardiac output, heart rate, and mixed venous oxygen saturation recovered toward baseline level more rapidly in the IG and IGK groups than in the C group (within 5 min versus more than 20 min). These results suggest that the infusion of insulin and glucose might reverse bupivacaine-induced cardiac depression in dogs. Implications We found that insulin and glucose rapidly reversed hemodynamic abnormality in dogs with bupivacaine-induced cardiac depression. This study implies a possible clinical application of insulin treatment for bupivacaine-induced cardiac depression.

Effects of Repeat Bolus Ethanol Injections on Cardiopulmonary Hemodynamic Changes during Embolotherapy of Arteriovenous Malformations of the Extremities

PURPOSE This study was designed to investigate the effects of repeat bolus absolute ethanol injections on cardiopulmonary hemodynamic changes during ethanol embolotherapy of inoperable congenital arteriovenous (AV) malformations in the extremities. MATERIALS AND METHODS Thirty adult patients (14 male, 16 female; age range, 22-51 years) who underwent ethanol embolotherapy of extremity AV malformations were enrolled in the study. A pulmonary artery catheter was used to measure hemodynamic profiles at baseline (T(baseline)), immediately before (T(pre)) and after (T(post)) a bolus injection of absolute ethanol, at the time of the maximum mean pulmonary arterial pressure (PAP) value during a session (T(highest)), 10 minutes after the final injection (T(final)), and after restoration of spontaneous breathing (T(resp)). RESULTS The systolic, mean, and diastolic PAP (P < .01, P < .01, and P < .01, respectively) and the systemic vascular resistance index (P < .05) and pulmonary vascular resistance index (PVRI; P < .05) of T(highest) and T(resp) were significantly higher than values for T(final). The volume of a single bolus injection of absolute ethanol from 0.023 to 0.175 mL/kg of body weight showed that the systolic PAP (P = .02), pulmonary capillary wedge pressure (P = .02), and PVRI (P < .01) significantly increased in accordance with the increased single volume of absolute ethanol. A significant increase of the right ventricular end-diastolic volume index and right ventricular end-systolic volume index were observed at a dose of more than 0.14 mL/kg of body weight for a single bolus injection of absolute ethanol. CONCLUSIONS During ethanol embolotherapy of extremity AV malformations, significant hemodynamic changes can arise during a bolus injection of absolute ethanol. Cardiopulmonary hemodynamic profiles should be monitored closely after a bolus injection of more than 0.14 mL/kg of body weight of absolute ethanol.

Predictive factors for response of peripheral arteriovenous malformations to embolization therapy: Analysis of clinical data and imaging findings

PURPOSE To find a significant predictive factor for the efficacy of endovascular treatment of peripheral arteriovenous malformations (AVMs). MATERIALS AND METHODS One hundred seventy-six patients (73 male patients and 103 female patients; mean age, 29.4 y) who underwent treatment for AVMs in the body or extremities were included. Per Schobinger classification, lesions in 31 patients (18%) were stage II, those in 136 (77%) were stage III, and those in nine (5%) were stage IV. AVMs were located in the extremities in 130 patients (74%) and in the trunk in 46 patients (26%). AVMs were angiographically classified as type I (n = 1), type II (n = 36), type IIIa (n = 6), type IIIb (n = 9 1), or complex type (n = 42). Demographic factors, clinical data, and imaging data were analyzed to determine a statistically significant relationship with overall clinical outcomes. RESULTS Overall, 68 patients (39%) were cured, 91 patients (52%) showed a partial response, nine patients (5%) showed no response, treatment failed in seven patients (4%), and treatment aggravated the condition in one patient (1%). The overall complication rate was 45% (79 of 176 patients). Minor complications developed in 62 patients (35%) and major complications developed in 17 (10%). Statistically, the extent of AVMs (odds ratio, 0.199) and angiographic classification (odds ratio, 0.162) were significant predictive factors for overall clinical outcome. CONCLUSIONS Endovascular treatment of peripheral AVMs, planned with consideration of anatomic extent and angiographic subtypes, is likely to yield good clinical results with low complication rates.

The Effects of Prehydration on the Properties of Cerebrospinal Fluid and the Spread of Isobaric Spinal Anesthetic Drug

BACKGROUND: In a two-part clinical study, we investigated the effect of the administration of fluids “prehydration” on the physical properties of cerebrospinal fluid (CSF) and intrathecal spread of local anesthetics. METHODS: First, in the clinical spinal anesthesia study, 68 patients were allocated randomly into the prehydration or nonprehydration groups. One group was prehydrated with 10 mL/kg of lactated Ringers solution, and spinal anesthesia was performed with 12 mg of 0.5% isobaric tetracaine in all patients at the lumbar level. The arterial blood pressure, heart rate, and sensory block level were assessed. Second, in a magnetic resonance image study, 24 male volunteers were enrolled. CSF motion variables were measured after infusion of 10 mL/kg of lactated Ringers solution to examine the net flow and volume displacement of the CSF at the L2–3 disk level. RESULTS: In the clinical study, there were no significant differences in arterial blood pressure, heart rate, and median peak sensory block level between the two groups, but the median time to reach peak sensory block level (26.4 ± 15.7 vs 16.5 ± 9.2 min, P < 0.05) was longer in group P. In posthydration magnetic resonance images, the CSF regurgitant fraction (caudal flow) was significantly increased after hydration, but the stroke volume, absolute stroke volume, mean flux, stroke distance, and mean velocity in the cranial direction were significantly decreased. CONCLUSIONS: Rapid crystalloid prehydration can affect CSF flow in the lumbar region, reducing cephalic spread of 0.5% isobaric tetracaine and delaying the time to reach the peak sensory level.

Efficacy of Milrinone versus Nitroglycerin in Controlling Pulmonary Arterial Hypertension Induced by Intravenous Injections of Absolute Ethanol in Anesthetized Dogs

PURPOSE To compare the attenuating effects of milrinone versus nitroglycerin on pulmonary artery pressure (PAP) increase caused by repeat intravenous bolus injection of absolute ethanol in anesthetized dogs. MATERIALS AND METHODS Twenty-four dogs were randomly distributed into three groups: a control group (group C), a nitroglycerin group (treated with a continuous infusion of nitroglycerin at 5.0 microg/kg/min; group N), and a milrinone group (treated with a continuous infusion of milrinone at 3.0 microg/kg/min after an initial bolus dose of 100 microg/kg; group M). Absolute ethanol (0.1 mL/kg) was injected at 10-minute intervals via a 5-F angiographic catheter advanced into the proximal portion of the inferior vena cava. Immediately before and after each intravenous injection of absolute ethanol, hemodynamic values were obtained through a pulmonary arterial catheter. RESULTS Group M showed more stable hemodynamic values of systolic, mean, and diastolic PAP and pulmonary vascular resistance (PVR) compared with groups C and N. In addition, group M showed significantly higher values of cardiac output versus group C at 10 minutes after the 10th bolus of ethanol. After restoration of spontaneous breathing, group M also showed the least hemodynamic changes in systolic, mean, and diastolic PAPs and PVR among the groups. CONCLUSIONS Although a continuous infusion of nitroglycerin or milrinone effectively prevented cardiovascular deterioration, milrinone was superior to nitroglycerin in managing the acute hemodynamic changes that resulted from repeated intravenous bolus injections of absolute ethanol (0.1 mL/kg) in healthy anesthetized dogs.

Comparison of respiratory mechanics between sevoflurane and propofol-remifentanil anesthesia for laparoscopic colectomy

Background The creation of pneumoperitoneum and Trendelenburg positioning during laparoscopic surgery are associated with respiratory changes. We aimed to compare respiratory mechanics while using intravenous propofol and remifentanil vs. sevoflurane during laparoscopic colectomy. Methods Sixty patients undergoing laparoscopic colectomy were randomly allocated to one of the two groups: group PR (propofol-remifentanil group; n = 30), and group S (sevoflurane group; n = 30). Peak inspiratory pressure (PIP), dynamic lung compliance (Cdyn), and respiratory resistance (Rrs) values at five different time points: 5 minutes after induction of anesthesia (supine position, T1), 3 minutes after pneumoperitoneum (lithotomy position, T2), 3 minutes after pneumoperitoneum while in the lithotomy-Trendelenburg position (T3), 30 minutes after pneumoperitoneum (T4), and 3 minutes after deflation of pneumoperitoneum (T5). Results In both groups, there were significant increases in PIP and Rrs while Cdyn decreased at times T2, T3, and T4 compared to T1 (P < 0.001). The Rrs of group PR for T2, T3, and T4 were significantly higher than those measured in group S for the corresponding time points (P < 0.05). Conclusions Respiratory mechanics can be adversely affected during laparoscopic colectomy. Respiratory resistance was significantly higher during propofol-remifentanil anesthesia than sevoflurane anesthesia.

A comparison among infusion of lidocaine and dexmedetomidine alone and in combination in subjects undergoing coronary artery bypass graft: a randomized trial.

BACKGROUND Previous studies have reported the cardioprotective effect of dexmedetomidine and lidocaine. We compared the effect of lidocaine and dexmedetomidine infusion during off-pump coronary artery bypass graft (OPCAB). METHODS 153 patients undergoing OPCAB were enrolled. The lidocaine group (n=36, Group LIDO) received an infusion of lidocaine 2 mg/kg/h after bolus 1.5 mg/kg; the dexmedetomidine group (n=40, Group DEX) received dexmedetomidine 0.3-0.7 μg/kg/h; the combined group (n=39, Group Combined) received infusion of both drugs; and the control group (n=38) received nothing. We measured serum creatinine kinase-myocardial band (CK-MB) and cardiac troponin I (cTnI) concentration before and immediately after the surgery, postoperative day (POD)#1 and #2. The complication rate and clinical outcomes were compared. RESULTS The concentration of cTnI was significantly lower in the Group LIDO and Group Combined than the control group on POD#2. The concentration of CK-MB was significantly lower in the Group LIDO and Group Combined compared to the control group on POD#1 and #2 [CK-MB on POD#1: 7.67 (5.78-11.92) vs. 7.18 (5.01-11.72) vs. 13.19 (6.85-23.87) in the Group LIDO, combined and control, respectively, Group LIDO vs. control: p=0.003, Group Combined vs. control: p=0.015]. The AUC of CK-MB was significantly lower in the Group LIDO and Group Combined than the control group. However, clinical variables including complication rate, ICU stay and one-year mortality were not different. CONCLUSIONS Lidocaine infused at 2 mg/kg/h, but not dexmedetomidine infused at 0.3-0.7 μg/kg/h reduced postoperative myocardial injury marker levels compared with the control group. However, no other clinical benefits were observed.

Cardiovascular Effects and Predictability of Cardiovascular Collapse after Repeated Intravenous Bolus Injections of Absolute Ethanol in Anesthetized Pigs

PURPOSE To evaluate the effects of repeated intravenous bolus injections of absolute ethanol on cardiopulmonary hemodynamic changes and to investigate the predictability of ethanol-induced cardiovascular collapse in anesthetized pigs. MATERIALS AND METHODS Twenty pigs aged 3-6 months and weighing 28-38 kg were enrolled in the study. Absolute ethanol (0.1 mL/kg of body weight) was repeatedly injected through the inferior vena cava central to the renal vein at 10-minute intervals up to a total volume of 1.0 mL/kg. The subjects were divided into a cardiovascular collapse group and a no-collapse group according to the development or absence of cardiac collapse. RESULTS Among the 20 pigs, 12 died before the final injection. Hemodynamic parameters measured immediately before the injection of absolute ethanol did not differ between the cardiovascular collapse group and the no-collapse group except that among animals with cardiovascular collapse, the injection immediately before the one causing cardiovascular collapse resulted in significant increases in the following hemodynamic parameters: mean pulmonary arterial pressure (P < .01), pulmonary vascular resistance (P = .04), and right ventricular end-diastolic volume (P = .02). No such increases were observed in the no-collapse group. CONCLUSIONS Hemodynamic profiles in pigs obtained immediately before intravenous injection of absolute ethanol did not predict the subsequent occurrence of cardiovascular collapse except after the injection immediately preceding the one resulting in cardiovascular collapse. In this animal model, significant increases in select hemodynamic parameters occurred after the injection immediately preceding the one resulting in cardiovascular collapse.

Sensitive micro-sample analysis of bisphenol A in serum by high-performance liquid chromatography with fluorescence detection

SummaryA rapid and sensitive HPLC method with fluorescence detection has been developed for the micro-sample analysis of bisphenol A in rat serum. Compounds were separated on a Spherisorb C18 analytical column with acetonitrile-0.1% triethylamine in deionized water, 54:46 (v/v), as mobile phase. Bisphenol A was isolated by one-step extraction with dichloromethane. The calibration plot was linear (r=0.999) over the concentration range 1–1000 ng mL−1. The limits of detection and quantitation were 0.2 ng mL−1 and 1 ng mL−1, respectively, for 100-μL serum samples. The assay was successfully used for a pharmacokinetic study after intravenous administration of a low dose (0.1 mg kg−1) of bisphenol A to rats.