Woo Seok Sim

Intravascular injection in lumbar medial branch block: a prospective evaluation of 1433 injections.

BACKGROUND: The successful outcome and validity of lumbar medial branch block (MBB) are largely dependent on technique accuracy. Intravascular uptake of injectate causes a false-negative response to block and is associated with various possible complications. In the current study, we prospectively evaluated the incidence of, and the factors associated with, intravascular injection during block. In addition, we assessed the efficiencies of generally accepted safety measures, such as preinjection aspiration and intermittent fluoroscopy to avoid intravascular injections. METHODS: We prospectively examined 1433 lumbar MBBs in 456 patients performed by seven physicians. Aspiration test, spot radiography, and contrast injection under real-time fluoroscopic visualization were performed sequentially without repositioning the needle. Incidences of blood flashback and the presence of intravascular contrast spread on spot radiographic images and during real-time fluoroscopy were checked. The factors studied for intravascular injection included physician experience, patient age and sex, needle gauge, and block spinal level. RESULTS: No specific factors were found to affect the incidence of intravascular uptake during block. The overall incidence of intravascular uptake was 6.1% per nerve block (88/1433), and 30 of these were predicted by preinjection aspiration (sensitivity = 34.1%) and 52 by spot radiography (sensitivity = 59.1%). CONCLUSIONS: The aspiration test with or without spot radiography frequently missed the intravascular uptake of contrast during lumbar MBBs. We strongly advocate the use of real-time fluoroscopy during contrast injection to increase diagnostic and therapeutic value and to avoid possible complications.

Is Intravenous Patient Controlled Analgesia Enough for Pain Control in Patients Who Underwent Thoracoscopy

This prospective randomized study was conducted to evaluate the efficacy of two common analgesic techniques, thoracic epidural patient-controlled analgesia (Epidural PCA), and intravenous patient-controlled analgesia (IV PCA), in patients undergoing lobectomy by the video-assisted thoracic surgical (VATS) approach. Fifty-two patients scheduled for VATS lobectomy were randomly allocated into two groups: an Epidural PCA group receiving an epidural infusion of ropivacaine 0.2%+fentanyl 5 µg/mL combination at a rate of 4 mL/hr, and an IV PCA group receiving an intravenous infusion of ketorolac 0.2 mg/kg+fentanyl 15 µg/mL combination at a rate of 1 mL/hr. Pain scores were then recorded using the visual analogue scale at rest and during motion (VAS-R and VAS-M, 0-10) for five days following surgery. In addition, we measured the daily morphine consumption, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), satisfaction score, and the incidence of side effects. Thirty-seven patients out of 52 completed the study (18 in the Epidural PCA group, 19 in the IV PCA group). There were no differences in the pain scores, analgesic requirements, pulmonary function, satisfaction score, and the incidence of side effects between groups. This indicates that IV PCA and Epidural PCA are equally effective to control the postoperative pain after VATS lobectomy, which suggests that IV PCA may be used instead of Epidural PCA.

Prolonged inspiratory time produces better gas exchange in patients undergoing laparoscopic surgery: A randomised trial

Laparoscopic surgery performed with a patient in the Trendelenburg position is known to have adverse effects on pulmonary gas exchange and respiratory mechanics. We supposed that prolonged inspiratory time can improve gas exchange at lower airway pressure.

Impact of hepatic macrovesicular and microvesicular steatosis on the postoperative liver functions after right hepatectomy in living donors.

PURPOSE The aim of this study was to evaluate the impact of macrovesicular (MaS) and microvesicular steatosis (MiS) on postoperative liver function in living donors undergoing right hepatectomy. METHODS We retrospectively reviewed the medical records of 450 living liver donors who underwent right hepatectomy between 2000 and 2009. First, we divided the donors into two groups according to the degree of MaS regardless of MiS: group MaS_5 (n=250), donors with <5% MaS and group MaS_30 (n=200), donors with 5% to 30% MaS. Second, we stratified donors according to the degree of MiS regardless of Mas: group MiS_5 (n=163), donors with <5% MiS, group MiS_30 (n=287), and 5%-30% MiS. We evaluated the peak values of total bilirubin (TB), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) until the thirtieth postoperative day (POD). Next, we assessed the relation between MaS or MiS and postoperative peak liver function tests using regression analysis. RESULTS Peak values of postoperative AST (227±77 vs 203±67, respectively) and ALT (232±85 vs. 198±72, respectively) were significantly higher in the group MaS_30 than MaS_5. Similarly, the peak values of AST (225±80 vs 194±50, respectively) and ALT (228±85 vs 186±60, respectively) were significantly higher in the group MiS_30 than the group MiS_5. Regression models showed a significant modifying influence of MiS (P<0.001) on postoperative peak ALT levels in addition to MaS (P<.036), suggesting have comparable influences of both MiS and MaS on hepatic injury. CONCLUSION Our results suggested that a mild degree of either MaS or MiS was associated with higher postoperative peak AST and ALT values. A regression analysis showed both MaS and MiS to display similar impacts on postoperative liver functions after living donor right hepatectomy.

Breakage of a thoracic epidural catheter during its removal -A case report-

The breakage of an epidural catheter is a rare complication during the removal of a thoracic epidural catheter. There are many causes to breakage of an epidural catheter, such as the characteristics of the catheter itself, patients factors (anatomy, position during insertion and removal of the catheter, and the BMI), and the difficulty of the procedure. Surgical removal is considered if there is a possibility that the retained catheter might cause neurological problems. We experienced a breakage of an epidural catheter during its removal, which led to surgical intervention. To prevent the catheter breakage during its removal, the catheter should be withdrawn without excessive tension. In addition, an understanding of the patients anatomy is essential.

Determination of Adequate Entry Angle of Lumbar Sympathetic Ganglion Block in Korean

Background The target of lumbar sympathetic ganglion block is the anterolateral surface of the L2, 3 and 4 vertebral bodies, where the lumbar sympathetic ganglion usually lies. In most cases, a block-needle is inserted approximately 5-8 cm lateral to spinous process on the skin and directed to the anterolateral surface of vertebral body obliquely. The purpose of this study is to determine the safe entry angle and entry point in Korean by using the abdominal CT scan images. Methods The abdominal CT images of eighty five patients were recruited to this study. The minimal angle aimed at the lumbar sympathetic ganglion that can pass through the lateral aspect of body and maximal angle that avoids puncturing the kidney, ureter or retroperitoneal space were measured. The distance from midline to skin entry point was also measured. Results There was no significant difference in entry angle among L2, 3, and 4 level. The entry angle was similar in the right and left side, and in males and females. The entry angle of old age group was significantly smaller than that of young age group. The calculated safe entry angle was 30.5 ± 0.4° and entry point was 7.7 ± 0.2 cm and 6.7 ± 0.1 cm lateral from midline in males and females respectively. Conclusions These measurements can be used as a reference for lumbar sympathetic ganglion block and radiofrequency lesioning. Prior to performing the lumbar sympathetic ganglion block for cancer patients, the abdominal CT scan should be reviewed to prevent complications.

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.

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.

The effects of intermittent inflow occlusion and hepatic steatosis on postoperative liver functions in living liver donors undergoing right hepatectomy.

BACKGROUND Intermittent inflow occlusion (IIO) is a safe, effective method to reduce blood loss during liver resection and preserve function even among patients with underlying diseases such as steatosis and cirrhosis. Therefore, we evaluated the impact of IIO on postoperative liver function tests (LFT) and on morbidity among living liver donors undergoing a right hepatectomy, including donors with mild degrees (5%-30%) of macrovesicular steatosis (MaS). METHODS We retrospectively reviewed the medical records of 186 living liver donors from August 2008 to September 2010. Donors were divided into two groups according to group IIO (n=81) versus Controls (no IIO, n=105). Within each group, donors were subdivided to evaluate Peak values of LFTs and complications into according the degree of MaS: group I_5 (n=36); IIO+<5% MaS, group I_30 (n=45); IIO+5%-30% MaS, group C_5 (n=55); Control+<5% MaS, and group C_30 (n=50); Control+5%-30% MaS. RESULTS Peak aspartate aminotransferase (AST) and alanine aminotransferase (ALT) among IIO were significantly higher than Non-IIO. These values in groups I_5 and I_30 were significantly higher than groups C_5 and C_30, respectively (all, P<.01). The overall postoperative complications were comparable between groups IIO and Non-IIO, but significantly higher among group I_30 than groups I_5 (P=0.024) and C_30 (P=.012). CONCLUSIONS Application of IIO in donors with mild macrosteatosis undergoing right hepatectomy showed significantly higher postoperative peak liver functions tests and number of overall complications than those without IIO.

A comparison of the effects of preanesthetic administration of crystalloid versus colloid on intrathecal spread of isobaric spinal anesthetics and cerebrospinal fluid movement.

BACKGROUND:Movement of the cerebrospinal fluid (CSF) is one of the most important factors in determining the intrathecal spread of isobaric spinal anesthetics. Preanesthetic administration of either crystalloid or colloid immediately before spinal anesthesia (preload) may result in different CSF pulsatile movement because of their different physical properties. We examined whether preload of crystalloid versus colloid may have different effects on the intrathecal spread of isobaric spinal anesthetics as a result of their different CSF dynamics regarding its pulsatile movement. METHODS:In a clinical study of isobaric spinal anesthesia, patients were allocated into 1 of 2 groups according to preload with either crystalloid (n = 30) or colloid (n = 30) before spinal anesthesia with 0.5isobaric tetracaine. The pulsatile movements of CSF at the L2-3 intervertebral space and midportion of the aqueduct of Sylvius were also examined by magnetic resonance images in healthy volunteers (n = 23) at 0, 30, and 60 minutes after administering either crystalloid or colloid. RESULTS:In the clinical study, the time to reach the peak sensory block level was delayed significantly in the crystalloid preload group (27.2 ± 17.8 minutes; P < 0.01) compared with the colloid preload group (13.9 ± 7.0 minutes). The median sensory block levels of the crystalloid preload group at 15 minutes (T10, P < 0.05) and 20 minutes (T9.5, P < 0.05) were significantly lower than those (T8, T7, respectively) of the colloid preload group. In the magnetic resonance imaging study, cranially directed CSF pulsatile movement decreased significantly at the L2-3 intervertebral intrathecal space at 30 minutes after crystalloid administration, but not after colloid administration. The CSF production rate significantly increased at 30 minutes (637 &mgr;L/min, P < 0.05) after crystalloid preload compared with the baseline measurement (448 &mgr;L/min), and then slightly decreased (609 &mgr;L/min) at 60 minutes. In the colloid preload group, the CSF production rate was not statistically significant compared with the baseline measurement (464, 512, and 542 &mgr;L/min at baseline, 30, and 60 minutes, respectively). CONCLUSIONS:Compared with a colloid preload, which may be comparable to the no-preload condition, crystalloid preload prolonged the time to reach the peak sensory block level in isobaric spinal anesthesia, which might have been caused by a significant decrease in CSF pulsatile movement. This attenuated CSF pulsatile movement in the crystalloid preload group might have resulted from significant increases of CSF production.