Woon-Seok Kang

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

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 µg/kg) before anesthesia induction and was infused (0.6 µg/kg/h) during surgery. Anesthesia was induced with a target-controlled infusion (TCI) of propofol (effect site concentration, Ce; 3 µg/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 µg/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.

Effect of ulinastatin on perioperative organ function and systemic inflammatory reaction during cardiac surgery: a randomized double-blinded study.

Background This study evaluated the efficacy of ulinastatin for attenuating organ injury and the release of proinflammatory cytokines due to cardiopulmonary bypass (CPB) during cardiac surgery. Methods Patients undergoing valvular heart surgery employing CPB were assigned to receive either ulinastatin (group U, n = 13) or a placebo (group C, n = 11) before the commencement of CPB. Hemodynamic data, parameters of major organ injury and function, and proinflammatory cytokines were measured after the induction of anesthesia (T1), after CPB (T2), at the end of anesthesia (T3), and at 24 hours after surgery (POD). Results The demographic data, CPB duration, and perioperative transfusions were not different between the groups. PaO2/FiO2 in group U was significantly higher than that in group C at T3 (3.8 ± 0.8 vs. 2.8 ± 0.7, P = 0.005) and at POD (4.0 ± 0.7 vs. 2.8 ± 0.7, P < 0.001). Creatine kinase-MB at POD in group U was significantly lower than that in group C (17.7 ± 8.3 vs. 33.7 ± 22.1, P = 0.03), whereas troponin I at POD was not different between the groups. Creatinine clearance and the extubation time were not different between the groups at POD. The dopamine infusion rate during the post-CPB period in group U was significantly lower than that in group C (1.6 ± 1.6 vs. 5.5 ± 3.3 µg/kg/min, P = 0.003). The interleukin-6 and tumor necrosis factor-α concentrations at T1, T2, and T3 as well as the incidences of postoperative cardiac, pulmonary and kidney injuries were not different between the groups. Conclusions Ulinastatin pretreatment resulted in an improved oxygenation profile and reduced inotropic support, probably by attenuating the degree of cardiopulmonary injury; however, it did not reduce the levels of proinflammatory cytokines.

Comparison of pulmonary gas exchange according to intraoperative ventilation modes for mitral valve repair surgery via thoracotomy with one-lung ventilation: a randomized controlled trial.

OBJECTIVE Impaired pulmonary gas exchange after cardiac surgeries with cardiopulmonary bypass (CPB) often occurs, and the selection of mechanical ventilation mode, pressure-controlled ventilation (PCV) or volume-controlled ventilation (VCV), may be important for preventing hypoxia and improving oxygenation. The authors hypothesized that patients with PCV would show better oxygenation, compared with VCV, during one-lung ventilation (OLV) for mitral valve repair surgery (MVP) via thoracotomy. DESIGN Randomized controlled trial. SETTING University teaching hospital. PARTICIPANTS Sixty patients in each group. INTERVENTIONS MVP was performed using thoracotomy with OLV by PCV or VCV. MEASUREMENTS AND MAIN RESULTS Arterial partial pressure of oxygen (PaO2) and fraction of inspired oxygen (FIO2) were measured before anesthesia induction (T0), at skin incision (T1), after administration of heparin (T2), at 30 minutes after CPB weaning (T3), just before departure from the operating room to the intensive care unit (ICU) (T4), and 1 hour after ICU admission (T5), and PaO2/FIO2 ratio was calculated. Peak inspiratory pressure (PIP) and mean inspiratory pressure (Pmean) were recorded at T1, T2, T3, and T4. No significant difference was noted in the PaO2/FIO2 ratio between the groups at any measured point. PIP in the PCV group at all measured points was lower than that in the VCV group (T1, p<0.001; T2, p<0.001; T3, p<0.001; T4, p=0.025, respectively). Pmean was not different between the two groups at any measured point. CONCLUSIONS PCV during OLV in patients undergoing MVP via a thoracotomy with OLV showed lower PIP compared with VCV, but this did not improve pulmonary gas exchange.

The Effect of Ulinastatin on Postoperative Blood Loss in Patients Undergoing Open Heart Surgery with Cardiopulmonary Bypass

This prospective, randomized, double-blind study evaluated the effect of ulinastatin on postoperative blood loss and transfusion requirements of patients undergoing open-heart surgery with cardiopulmonary bypass (CPB) and aortic cross-clamping (ACC). CPB and ACC produce variable systemic inflammatory reactions that are associated with multiorgan dysfunction via leucocytes, especially polymorphonuclear neutrophils (PMNs). PMNs increase blood loss and transfusion requirements. Ulinastatin, a urinary trypsin inhibitor, inhibits PMN activity and reduces the systemic inflammatory response. Patients received either 5000 U/kg ulinastatin or the equivalent volume of normal saline (control group) before ACC. Postoperative blood loss and transfusion requirements were recorded. Duration of intubation and length of stay in the intensive care unit (ICU) were also noted. There were no statistically significant between-group differences in postoperative blood loss and transfusion requirements. Ulinastatin caused a non-significant decrease in duration of intubation. Patients who received ulinastatin had significantly shorter ICU stays than control patients.

The influence of positive end-expiratory pressure on stroke volume variation in patients undergoing cardiac surgery: an observational study.

OBJECTIVES Measurements of stroke volume variation for volume management in mechanically ventilated patients are influenced by various factors, such as tidal volume, respiratory rate, and chest/lung compliance. However, research regarding the effect of positive end-expiratory pressure on stroke volume variation is limited. METHODS Patients were divided into responder and nonresponder groups according to the prediction of fluid response by the passive leg raising test and hemodynamic parameters, including stroke volume variation, measured in all patients at the following ventilator settings: (1) conventional ventilation (C), tidal volume 10 mL · kg(-1) with positive end-expiratory pressure settings of 0 (C0), 5 (C5), and 10 cmH2O (C10) and (2) lung protective ventilation (P), tidal volume 6 mL · kg(-1) with positive end-expiratory pressure settings of 0 (P0), 5 (P5), and 10 cmH2O (P10). RESULTS Regardless of ventilator setting, stroke volume variation in the responder group had an increasing trend as increased positive end-expiratory pressure level and was significantly higher than in the nonresponder group at each positive end-expiratory pressure level. The area under the curve was (1) 0.899 at C0, 0.942 at C5, and 0.985 at C10; and (2) 0.901 at P0, 0.932 at P5, and 0.947 at P10. Optimal threshold values given by receiver operating characteristic curve analysis were (1) 13.5%, 13.5%, and 14.5%; and (2) 13.5%, 13.5%, and 14.5%, respectively. CONCLUSIONS The threshold value of stroke volume variation in predicting fluid responsiveness may change when positive end-expiratory pressure 10 cmH2O is applied. This must be considered when stroke volume variation is used to detect the fluid responsiveness to prevent volume overload in this mechanical ventilation setting.

Noninvasive cardiac output monitoring in paediatric cardiac surgery: correlation between change in thoracic fluid content and change in patient body weight.

Objective: Change in thoracic fluid content (TFC) derived via a bioreactance technique with a noninvasive cardiac output monitoring device (NICOM) reportedly shows a good correlation with the amount of fluid removed. The present study prospectively evaluated the utility and clinical application of TFC in the intraoperative fluid management of paediatric patients with congenital heart disease, undergoing cardiac surgery with bioreactance-based noninvasive monitoring. Methods: Haemodynamic parameters, patient body weight and parameters derived from the NICOM device (including cardiac output, cardiac index, TFC, percentage change in TFC compared with baseline [TFCd0%] and stroke volume variation) were recorded after anaesthesia induction but before surgical incision, and just before departure from the operating room to the intensive care unit. Results: In the 80 paediatric patients included in this study, linear regression analyses demonstrated good correlations between body weight gain and TFCd0%, between body weight gain % and TFCd0%, and between intra -operative fluid balance and TFCd0%. Conclusion: TFCd0% may be a useful indicator for intraoperative fluid management in paediatric patients with congenital heart disease, undergoing cardiac surgery.

The influence of different mechanical ventilator settings of peak inspiratory pressure on stroke volume variation in pediatric cardiac surgery patients

Background The usefulness of dynamic parameters derived by heart-lung interaction for fluid responsiveness in pediatric patients has been revealed. However, the effects of peak inspiratory pressure (PIP) that could affect the absolute values and the accuracy in pediatric patients have not been well established. Methods Participants were 30 pediatric patients who underwent ventricular septal defect repair. After completion of surgical procedure and sternum closure, mean arterial blood pressure, heart rate, central venous pressure, cardiac output, cardiac index and stroke volume variation (SVV) were measured at PIP 10 cmH2O (PIP10), at PIP 15 cmH2O (PIP15), at PIP 20 cmH2O (PIP20) and at PIP 25 cmH2O (PIP25). Results SVV at PIP15 was larger than that at PIP10 (13.7 ± 2.9% at PIP10 vs 14.7 ± 2.5% at PIP15, P < 0.001) and SVV at PIP20 was larger than that at PIP10 and PIP15 (13.7 ± 2.9% at PIP10 vs 15.4 ± 2.5% at PIP20, P < 0.001; 14.7 ± 2.5% at PIP15 vs 15.4 ± 2.5% at PIP20, P < 0.001) and SVV at PIP25 was larger than that at PIP10 and PIP15 and PIP20 (13.7 ± 2.9% at PIP10 vs 17.4 ± 2.4% at PIP25, P < 0.001; 14.7 ± 2.5% at PIP15 vs 17.4 ± 2.4% at PIP25, P < 0.001; 15.4 ± 2.5% at PIP20 vs 17.4 ± 2.4% at PIP25, P < 0.001). Conclusions SVV is affected by different levels of PIP in same patient and under same volume status. This finding must be taken into consideration when SVV is used to predict fluid responsiveness in mechanically ventilated pediatric patients.

Effect of Mechanical Ventilation Mode Type on Intra- and Postoperative Blood Loss in Patients Undergoing Posterior Lumbar Interbody Fusion Surgery: A Randomized Controlled Trial.

Background:The aim of study was to evaluate the effect of mechanical ventilation mode type, pressure-controlled ventilation (PCV), or volume-controlled ventilation (VCV) on intra- and postoperative surgical bleeding in patients undergoing posterior lumbar interbody fusion (PLIF) surgery. Methods:This was a prospective, randomized, single-blinded, and parallel study that included 56 patients undergoing PLIF and who were mechanically ventilated using PCV or VCV. A permuted block randomization was used with a computer-generated list. The hemodynamic and respiratory parameters were measured after anesthesia induction in supine position, 5 min after patients were changed from supine to prone position, at the time of skin closure, and 5 min after the patients were changed from prone to supine position. The amount of intraoperative surgical bleeding, fluid administration, urine output, and transfusion requirement were measured at the end of surgery. The amount of postoperative bleeding and transfusion requirement were recorded every 24 h for 72 h. Results:The primary outcome was the amount of intraoperative surgical bleeding, and 56 patients were analyzed. The amount of intraoperative surgical bleeding was significantly less in the PCV group than that in the VCV group (median, 253.0 [interquartile range, 179.0 to 316.5] ml in PCV group vs. 382.5 [328.0 to 489.5] ml in VCV group; P < 0.001). Comparing other parameters between groups, only peak inspiratory pressure at each measurement point in PCV group was significantly lower than that in VCV group. No harmful events were recorded. Conclusion:Intraoperative PCV decreased intraoperative surgical bleeding in patients undergoing PLIF, which may be related to lower intraoperative peak inspiratory pressure.

Placing a Saline Bag Underneath the Heart Enhances Transgastric Transesophageal Echocardiographic Imaging During Cardiac Displacement for Off-Pump Coronary Artery Bypass Surgery

OBJECTIVE The authors hypothesized that placing a saline bag (saline-filled surgical glove) underneath a displaced heart would improve ultrasound transmission for transgastric (TG) imaging and transesophageal echocardiography (TEE) to visualize left ventricular regional wall motion (LV-RWM) during cardiac displacement for off-pump coronary artery bypass (OPCAB) surgery. DESIGN Prospective observational study. SETTING Tertiary University Hospital. PARTICIPANTS Adult patients undergoing OPCAB surgery. INTERVENTIONS Intraoperative TEE examination MEASUREMENT AND MAIN RESULTS For off-line analyses of LV-readable segments, mid-esophageal (ME, 4-chamber, 2-chamber, and long-axis) and TG (basal- and mid-short-axis) TEE views were recorded under 3 different intraoperative conditions in 13 cases of OPCAB surgery: Before cardiac displacement (Tcontrol), after cardiac displacement (Tdisplaced), and after placing the saline bag underneath the displaced heart (Tsaline-bag). There were more LV-readable segments in the 17-segment model using integrated ME and TG views(ME + TG views) at Tsaline-bag and Tcontrol (mean[95% confidence interval], 17[17-17] and 17[17-17]) than using ME+TG at Tdisplaced (15[15-16], P = 0.002 and P<0.001, respectively). Using ME + TG views provided more LV-readable segments in the 17-segment model than using ME views at Tsaline-bag (vs. 16[14-16], P < 0.001), but not at Tdisplaced (vs. 15[14-15]). Incidences of inadequate RWM monitoring (LV-readable segments<14/17 using ME + TG views) at Tsaline-bag and Tcontrol (all 0/13) were less frequent than at Tdisplaced (3/13, all P = 0.038). There were more LV-readable segments in TG basal- and mid-short-axis views at Tsaline-bag (median [range], 6[5-6] and 5[5-6]) than at Tdisplaced (0[0-2] and 0[0-1], all P < 0.05). CONCLUSIONS Placing a saline bag underneath the displaced heart enhances the ability of TEE to visualize global LV-RWM by improving TG TEE imaging during OPCAB surgery.

Comparison of the PaO2/FiO2 ratio in sternotomy vs. thoracotomy in mitral valve repair: a randomised controlled trial.

Objective Cardiac surgery through a thoracotomy using one-lung ventilation (OLV) is thought to be associated with worse postoperative pulmonary gas exchange than sternotomy using two-lung ventilation (TLV), but this has not been confirmed yet. We, therefore, compared postoperative pulmonary gas exchange after mitral valve repair between sternotomy (group TLV) and thoracotomy (group OLV). Design Randomised controlled study. Setting University teaching hospital. Participants Cardiac surgery patients. Intervention Sternotomy or thoracotomy was used for mitral valve repair. Measurements The ratio of arterial partial pressure of oxygen (PaO2) to fraction of inspired oxygen (FiO2) was compared in both groups before induction of anaesthesia (T0) and just before departure from the operating room to the ICU (T1). Fluid administration, transfusion requirements and urine output were checked intraoperatively. Postoperative haemoglobin (Hb), haematocrit (Hct) and creatinine were evaluated. Cardiopulmonary bypass (CPB) time, intubation time and ICU stay were also recorded. Results The PaO2/FiO2 ratio (mean ± SD) at T1 was significantly lower than at T0 in both groups (326.9 ± 120.1 vs. 431.9 ± 73.7 mmHg in group TLV, P < 0.001; 374.9 ± 130.9 vs. 445.4 ± 73.7 mmHg in group OLV, P = 0.001), but did not differ significantly between the two groups. The doses of inotropes and vaopressors used were not significantly different between the groups. Intraoperative fluid administration, transfusion requirements, urine output and postoperative Hb/Hct and creatinine did not differ significantly between the groups. CPB time, intubation time and ICU stay also did not differ significantly between the groups. Conclusion Perioperative pulmonary function following OLV via a thoracotomy was not significantly worse than that following TLV via a sternotomy in mitral valve repair. Clinical trial registration Not registered.