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Biomedical subjects

J H Bahk

Publications and source records attributed to J H Bahk.

At least 19 recordsLinked to original sources
PubMed2005

Intrathecal clonidine does not reduce post-spinal shivering.

BACKGROUND: After general or epidural anesthesia, clonidine is known to be effective in suppressing established shivering. The aim of this study was to assess the preventive effect of intrathecal clonidine on post-spinal shivering compared with intravenous (i.v.) clonidine. METHODS: One hundred and fifty patients scheduled for orthopedic surgery were randomly allocated into three groups to receive either 1 microg/kg clonidine i.v. (IV group) or the same volume of isotonic saline (control and IT groups) at 5 min before spinal anesthesia. Spinal anesthesia was performed with 12-15 mg hyperbaric bupivacaine 0.5% plus either 1 ml of saline (control and IV groups) or 150 microg clonidine (IT group). Shivering was evaluated for a period of 90 min and graded as none, mild, moderate, and severe. RESULTS: Twenty patients (40%) in the control group and 17 patients (34%) in the IT group showed shivering compared with four (8%) in the IV group. Patients with moderate-to-severe shivering were only seen in the control and IT group, and the maximal intensity of shivering was not different between the two groups. Patients in the IV group were significantly more sedated than the other groups. CONCLUSIONS: The intrathecal administration of clonidine 150 microg fails to prevent post-spinal shivering; by contrast, we have confirmed that i.v. clonidine 1 microg/kg is an effective method to prevent shivering in patients undergoing spinal anesthesia for orthopedic surgery.

Adolescent↗
PubMed2005

A new technique to determine the size of double-lumen endobronchial tubes by the two perpendicularly measured bronchial diameters.

The cross-section of the mainstem bronchi is not completely round. For preoperative selection of a double-lumen endobronchial tube size, it may be necessary to measure the mediolateral and the anteroposterior bronchial diameters, which can be measured respectively on chest radiograph and computed tomography. With Internal Review Board approval and patients' informed consent, 105 elective thoracic surgical patients who needed left-sided double-lumen tubes were enrolled. Double-lumen tube size was selected depending on the arithmetic mean of the mediolateral and anteroposterior bronchial diameters. Moreover, the outer diameters of the bronchial tube should be smaller than both mediolateral and anteroposterior diameters. The recommended bronchial diameter for each double-lumen tube size was chosen so that the mean of the two bronchial diameters was 0 to 2.0 mm larger than the upper limit of 95% confidence interval of the averaged outer diameter of the bronchial tube of the selected double-lumen tube. In no case was the predicted double-lumen tube size inappropriate. Generally, anteroposterior bronchial diameters appeared to be different from mediolateral diameters (P=0.001). The double-lumen tube size to be selected based on only one bronchial diameter was different from the one selected based on two perpendicularly measured bronchial diameters in 54.3% of patients (57/105). Preoperative selection of the double-lumen tube size based on the anteroposterior, mediolateral and mean bronchial diameters seems to be useful in that this may obviate the need to change an inappropriately sized double-lumen tube and may be helpful in reducing the related complications.

Adult↗
PubMed2005

Intra- and extra-pericardial lengths of the superior vena cava in vivo: implication for the positioning of central venous catheters.

To reduce the possibility of cardiac tamponade, a rare but lethal complication of central venous catheters, the tip of the central venous catheter should be located above the cephalic limit of the pericardial reflection, not only above the superior vena cava-right atrium junction. This study was performed to measure the superior vena cava lengths above and below the pericardial reflection in cardiac surgical patients. Cardiac surgical patients (n = 61; 27 male), whose age [mean +/- SD (range)] was 47 +/- 15 (15-75) years, were studied. The intrapericardial and extrapericardial lengths, and the length of the medial duplicated part were measured separately. The whole vertical lengths of the superior vena cava on either side were calculated respectively by adding the intra-and extrapericardial and medial duplication lengths. The lateral extrapericardial was 29.1 +/- 6.5 (Mean +/- SD) (9-49) mm (range), and lateral extrapericardial length was 32.6 +/- 6.9 (20-53) mm. The medial extrapericardial length was 23.3 +/- 5.0 (11-39) mm, medical duplicated length was 7.2 +/- 3.3 (4-20) mm, and medial intrapericardial was 28.3 +/- 7.0 (20-52) mm. The averaged superior vena cava length of both sides was 60.3 +/- 9.0 (44.5-90) mm. Almost half of the superior vena cava was found to be within the pericardium and half out. This information may be helpful in deciding how far a central venous catheter should be withdrawn beyond the superior vena cava-right atrial junction during right atrial electrocardiographic guided insertion, and in the prediction of optimal central venous catheter insertion depth.

Adolescent↗
PubMed2004

The effect of bloodless pump prime on cerebral oxygenation in paediatric patients.

BACKGROUND: In paediatric patients, crystalloid prime for cardiopulmonary bypass (CPB) causes further haemodilution in comparison with blood-containing prime. Thus it may affect the cerebral oxygen supply/demand balance. The purpose of the study was to compare the effect of bloodless pump prime with that of blood-containing prime on cerebral oxygenation in children. METHODS: Thirty-six paediatric patients scheduled for elective repair of atrial or ventricular septal defect were enrolled. In Group C (n = 18), the CPB circuit was primed only with crystalloid. In Group B (n = 18), red blood cells were added to achieve a haematocrit (Hct) of 20% during CPB. The regional cerebral oxygen saturation (rSO(2)) value measured by near-infrared spectroscopy was compared between the two groups. RESULTS: In both groups, rSO(2) decreased below baseline at the start of CPB and during rewarming (P < 0.001, for both groups during each period). At the start of CPB, haemodilution was greater in Group C than in Group B (Hct 16.1 +/- 0.7% vs. 20.7 +/- 0.5%; P < 0.01), and there was a greater reduction in rSO(2) in Group C (49.0 +/- 5.4% vs. 59.2 +/- 7.0%; P < 0.01). During rewarming, rSO(2) was significantly lower in Group C than in Group B (57.8 +/- 5.3% vs. 62.8 +/- 6.2%; P < 0.01). CONCLUSIONS: In paediatric patients, the haemodilution associated with crystalloid priming causes a greater reduction in rSO(2) than with blood-containing prime at the starting period of CPB and the rewarming period.

Analysis of Variance↗
PubMed2004

The effect of acute normovolemic haemodilution on cerebral oxygenation.

Acute normovolemic haemodilution (ANH) may cause an imbalance in cerebral oxygen metabolism because it decreases the arterial oxygen content. This study was designed to investigate the effect of ANH on cerebral oxygenation. By using cerebral oximetry, the regional cerebral oxygen saturation (rSO2) was monitored during ANH in 26 patients without systemic illness (initial haematocrit = 42 +/- 1%). The rSO2 did not show a significant change until the Hct reached >30%. However, it decreased significantly thereafter to reach 88% of the baseline value when the ANH was completed with a Hct value of 24 +/- 1% (before ANH; 71 +/- 6% vs. after ANH; 62 +/- 4%, p < 0.01). In conclusion, an ANH can lead to a reduction in cerebral oxygenation when a patient's Hct goes below 30%.

Blood Flow Velocity↗
PubMed2003

Clinical trial of esmolol-induced controlled hypotension with or without acute normovolemic hemodilution in spinal surgery.

BACKGROUND: Drug-induced controlled hypotension (CH) combined with acute normovolemic hemodilution (ANH) is being widely used for blood conservation in surgical patients. The purpose of this study was to investigate the efficacy and safety of esmolol-induced CH combined with ANH (hematocrit down to 28%). METHODS: Thirty patients who were scheduled to receive spinal surgery were randomly divided into two groups: an esmolol-induced CH alone group (esmolol group, n=15) and a CH-ANH combined group (E-ANH group, n=15). Controlled hypotension was induced with esmolol 500 micro g/kg, followed by a continuous infusion of 0-300 micro g/kg/min to maintain mean arterial pressure at 55-65 mmHg. RESULTS: The mean infusion rate of esmolol in the esmolol-ANH group was 46+/-6 micro g/kg/min (mean+/-SD), which was significantly lower than the 77+/-9 micro g/kg/min used in the esmolol group (P<0.05). The number of units of homologous blood (packed RBC) transfused perioperatively was 2.2+/-0.6 units in the esmolol-ANH group, which was significantly less than 4.3+/-0.4 units used in the esmolol group (P<0.01). While O2 delivery decreased significantly during CH, O2 consumption remained unchanged in both groups. No complications resulted from CH or ANH in any of the groups. CONCLUSION: Our data suggest that ANH of moderate degree can be combined with esmolol-induced CH to improve blood conservation in surgical patients.

Adrenergic beta-Antagonists↗
PubMed2003

Use of a Fogarty catheter as a bronchial blocker through a single-lumen endotracheal tube in patients with subglottic stenosis.

One-lung ventilation can be achieved with a double-lumen tube or a bronchial blocker. However, the larger outer diameters of double-lumen or Univent tubes may prevent their passage through an area of subglottic stenosiss. We present five cases of subglottic stenosis in which a Fogarty catheter was used as a bronchial blocker through a single-lumen endotracheal tube. The outer diameters of a double-lumen tube, Univent tube and single-lumen tube were compared. Despite special equipment designed for one-lung ventilation, the use of a bronchial blocker through a single-lumen tube, which has the thinnest available wall thickness, seems to be one of the most effective and safest ways of achieving one-lung ventilation in patients with subglottic stenosis or narrowing.

Aged↗
PubMed2002

Coiling of lumbar epidural catheters.

BACKGROUND: The difficulties in threading an epidural catheter to vertebral levels remote to the puncture level have been well documented. This study was undertaken to determine the length that a single orifice epidural catheter can be threaded into the lumbar space without coiling (coiling length), and whether this is affected by the direction of the epidural needle bevel. METHODS: Forty-five young male patients scheduled for surgery under epidural analgesia were enrolled. The epidural space was identified using a midline approach at the L(2-3) or L(3-4) interspace with the loss of resistance to air technique. A 19-G single-orifice epidural catheter (Flextip Plus, Arrow International, Inc, Reading, PA, USA) was inserted through a Tuohy needle oriented either cephalad (n=20) or caudad (n=25). During insertion, the path and the position of the catheter tip was determined by fluoroscopy using iohexol dye. RESULTS: The median coiling length was 2.8 cm, ranging from 1.0 to 8.0 cm. Only 13% of epidural catheters could be threaded 4 cm beyond the tip of the needle without coiling. No significant difference was found in coiling length between the cephalad group (2.9 cm) and the caudad group (2.5 cm). CONCLUSION: This study demonstrates that coiling length is independent of whether the bevel of the Tuohy needle is directed cephalad or caudad. We recommend that an optimal insertion depth of an end-hole single orifice catheter is 3 cm.

Adult↗
PubMed2001

The laryngeal mask airway in infants and children.

PURPOSE: To compare the effectiveness of various laryngeal mask airway (LMA) sizes and their performance during positive pressure ventilation (PPV) in paralyzed pediatric patients. METHODS: Pediatric patients (n = 158), < 30 kg, ASA 1 or 2 were studied. After paralysis, an LMA of the recommended size was inserted and connected to a volume ventilator. Fibreoptic bronchoscopy (FOB) was performed and graded: 1, larynx only seen; 2, larynx and epiglottis posterior surface seen; 3, larynx, and epiglottis tip or anterior surface seen--visual obstruction of epiglottis to larynx: < 50%; 4, epiglottis down-folded, and its anterior surface seen--visual obstruction of epiglottis to larynx: > 50%; 5, epiglottis down-folded and larynx not seen directly. Inspiratory and expiratory tidal volumes (V(T)), and airway pressure were measured by a pneumo-tachometer, and the fraction of leakage (F(L)) was calculated. In 79 cases, LMA was used for airway maintenance throughout surgery. RESULTS: Successful LMA placement was achieved in 98% of cases: three failures were due to gastric insufflation. For LMA # 1, 1.5, 2, and 2.5, FOB grades [median (range)] were 3(1-5), 3(1-5), 1(1-5) and 1(1-3) respectively. In smaller LMAs, the cuff more frequently enclosed the epiglottis (P < .001). F(L) of LMA # 1 was higher than those of LMA # 1.5 and LMA # 2.5 (P < .05), and F(L) of LMA # 2 was higher than that of LMA # 2.5 (P < .05). In the 79 patients, the number of patients experiencing complications decreased as LMA size increased (P < .05). CONCLUSION: Use of the LMA in smaller children results in more airway obstruction, higher ventilatory pressures, larger inspiratory leak, and more complications than in older children.

Child↗
PubMed2000

Positioning of a double-lumen endobronchial tube without the aid of any instruments: an implication for emergency management.

BACKGROUND: Lung isolation and preservation of normal lung are the first lines of therapy in life-threatening massive hemoptysis. If bleeding continues but the side of origin is uncertain, use of a double-lumen tube (DLT) is reasonable. Utilizing a blind method to locate the bronchial cuff of a left-sided DLT without using any instrument, a DLT (Broncho-Cath, Mallinckrodt Medical Ltd., Athlone, Ireland) was successfully positioned without delay in a patient with massive hemoptysis, where auscultation could be misleading or useless and fiberoptic bronchoscope (FOB) was inapplicable. This study was performed to discern whether this blind method could substitute for FOB verification or auscultation in most circumstances where these two methods are unavailable or inapplicable. METHODS: After receiving informed consent and hospital ethics board approval, 58 elective thoracic surgical patients, aged 17 to 67 years, were enrolled in the study and divided into two groups. A conventional method using an FOB was used to locate the left-sided DLT in 29 patients (group 1). In the other 29 patients (group 2), the blind manual method was used. The left-sided DLT was inserted until some resistance was felt, at which time the bronchial cuff was inflated with approximately 2.0 mL of air. While gently holding the pilot with thumb and index finger of the nondominant hand, the DLT was slowly withdrawn until an abrupt decrease of pilot pressure was sensed. At that moment, the bronchial cuff was deflated, and the DLT was advanced approximately 1.5 cm; using an FOB, its position was checked by an independent observer not involved in positioning the DLT. Success was defined as the point when the proximal margin of the carina was within the margin of safety for the DLT, which is defined as the difference between the length of the left main bronchus and the length of the tube between the proximal margin of the left bronchial cuff and the left lumen tip. Postoperative FOB was performed to evaluate bronchial injury. RESULTS: In 26 of 29 patients (group 2), the position of the DLT was bronchoscopically confirmed to be a success. The other three cases were deemed to be too shallow; specifically, the bronchial cuffs were slightly herniated onto the carina (acceptable position). This method was more traumatic than FOB-guided DLT intubation (conventional method) (p = 0.001); however, the most severe damage was erosion. CONCLUSION: This method, which requires no specific instrument and no time-consuming technique, can be taught easily and may be used in a situation where the rapidity of lung isolation or collapse is the key to saving life. We conclude that this blind method can be an alternative to the FOB and/or auscultation for the positioning of DLT in an emergency situation.

Adolescent↗