Microcirculation during surgery

Throughout the long history of surgery, there has been great advancement in the hemodynamic management of surgical patients. Traditionally, hemodynamic management has focused on macrocirculatory monitoring and intervention to maintain appropriate oxygen delivery. However, even after optimization of macro-hemodynamic parameters, microcirculatory dysfunction, which is related to higher postoperative complications, occurs in some patients. Although the clinical significance of microcirculatory dysfunction has been well reported, little is known about interventions to recover microcirculation and prevent microcirculatory dysfunction. This may be at least partly caused by the fact that the feasibility of monitoring tools to evaluate microcirculation is still insufficient for use in routine clinical practice. However, considering recent advancements in these research fields, with more popular use of microcirculation monitoring and more clinical trials, clinicians may better understand and manage microcirculation in surgical patients in the future. In this review, we describe currently available methods for microcirculatory evaluation. The current knowledge on the clinical relevance of microcirculatory alterations has been summarized based on previous studies in various clinical settings. In the latter part, pharmacological and clinical interventions to improve or restore microcirculation are also presented.

Newly detected patent ductus arteriosus by transesophageal echocardiography in patient who underwent cardiopulmonary bypass: A case report

Transesophageal echocardiography is a useful device to evaluate the posterior structure of heart with an advantage of enabling clearer images, as compared to transthoracic echocardiography. With intraoperative transesophageal echocardiography, we can reconfirm pre-diagnosed lesions, determine the success of the operation, and in particular, diagnose new lesions that are undetected in pre-operative evaluation. In the present case, undiagnosed patent ductus arteriosus was found on intraoperative transesophageal echocardiography during cardiopulmonary bypass. Subsequently, the patent ductus arteriosus was ligated successfully. With transesophageal echocardiography, we can diagnose the structural and functional abnormality of heart unidentified in the pre-operative evaluation. Also, transesophageal echocardiography can play the role of a rescuer to solve the problems that occur during cardiopulmonary bypass.

Anesthetic management of antiphospholipid syndrome patients who underwent cardiac surgery: three cases report / 대한마취과학회지

Antiphospholipid syndrome (APS) is a rare disease in which patients display prolonged coagulation test results in vitro, but usually develop thrombotic symptoms in vivo. Patients with APS are at increased risk of valvular heart disease or coronary vascular disease, conditions that often necessitate cardiac surgery via bypass. The management of anticoagulation during cardiopulmonary bypass (CPB) is particularly challenging in these patients because of the unique features of APS. Patients with APS are constantly at risk of arterial and venous thrombotic events. Therefore it is very important to maintain proper anticoagulation perioperatively, especially during CPB. In this paper, we present three successful cases of APS patients who underwent cardiac surgery with CPB.

Left ventricular outflow tract obstruction with systolic anterior motion of the mitral valve in patient with pericardial effusion caused by ascending aortic dissection: A case report / 대한마취과학회지

Left ventricular outflow tract (LVOT) obstruction with systolic anterior motion (SAM) of mitral valve is not only limited to patients with hypertrophic cardiomyopathy. A diagnosis of LVOT obstruction with SAM is important because conventional inotropic support may potentially aggravate hemodynamic deterioration. We present a case of LVOT obstruction with SAM in a patient who underwent an emergent surgery for ascending aortic dissection with pericardial effusion. The patient showed refractory hypotension after standard pharmacologic interventions during induction of anesthesia. Transesophageal echocardiography (TEE) revealed LVOT obstruction with SAM and it was managed appropriately under the guidance of TEE. Intraoperative TEE can play an important role in diagnosis and management of LVOT obstruction with SAM caused by pericardial effusion.

Predictability of passive leg raising test on anesthesia-induced hypotension in patients undergoing cardiac surgery

BACKGROUND: Hypotension often occurs after induction of general anesthesia. Although preload status has been considered as an important factor for the occurrence of this hypotension, there have been inconsistent results on this topic. The dynamic preload parameters have not been studied as a predictor of hypotension, and therefore we hypothesized that the passive leg raising (PLR) test, a dynamic preload parameter, could predict anesthesia-induced hypotension and conducted a prospective clinical study. METHODS: In 40 patients undergoing elective cardiac surgery, mean arterial pressure (MAP), stroke volume variation, stroke volume (SV) and cardiac index (CI) were measured using arterial line and FloTrac(TM)/Vigileo(TM) system before, during and after PLR test, respectively. Occurrence of anesthesia-induced hypotension was recorded. The ability of PLR test to predict hypotension was evaluated by receiver operating characteristic (ROC) curve analysis. RESULTS: The incidence of hypotension was 90%, which includes 12.5% of refractory hypotension. Changes in MAP and CI induced by PLR test predicted hypotension (area under ROC curves: 0.722 and 0.788, respectively). Changes in SV and CI induced by PLR test predicted refractory hypotension (area under ROC curves: 0.863 and 0.789, respectively). CONCLUSIONS: Our results suggest that PLR test can predict hypotension and refractory hypotension occurring after induction of anesthesia in patients undergoing cardiac surgery.

An undiagnosed pseudoaneurysm found during arterial catheterization in a Takayasu arteritis patient / 대한마취과학회지

No abstract available.

Effect of airway pressure on lumbar epidural pressure during positive pressure ventilation / 대한마취과학회지

BACKGROUND: The purpose of this study was to measure lumbar epidural pressure (EP) during the insertion of a Tuohy needle under general anesthesia and to evaluate the influence of airway pressure on EP. METHODS: Lumbar EP was measured directly through a Tuohy needle during intermittent positive pressure ventilation in fifteen patients. Mean and peak EP were recorded after peak inspiratory pressures (PIP) of 0, 15, and 25 cmH2O. RESULTS: All measured lumbar EPs were positive, with the pressure increasing during inspiration and decreasing during expiration. Median EP was 6.0 mmHg (interquartile range, 4.0-8.0) at 0 cmH2O of PIP, 6.5 mmHg (4.5-8.5) at 15 cmH2O, and 8.5 mmHg (6.0-10.5) at 25 cmH2O, increasing significantly at 15 cm H2O PIP, and further increasing at 25 cmH2O (P < 0.001). CONCLUSIONS: We demonstrate the influence of increased airway pressure on lumbar EP measured directly through a Tuohy needle. Lumbar EPs were positive, and increasing PIP levels significantly increased lumbar EP.

Preoperative Aspirin Resistance does not Increase Myocardial Injury during Off-pump Coronary Artery Bypass Surgery

We performed a prospective cohort trial on 220 patients undergoing elective off-pump coronary artery bypass surgery and taking aspirin to evaluate the effect of aspirin resistance on myocardial injury. The patients were divided into aspirin responders and aspirin non-responders by the value of the aspirin reaction units obtained preoperatively using the VerifyNow(TM) Aspirin Assay. The serum levels of troponin I were measured before surgery and 1, 6, 24, 48 and 72 hr after surgery. In-hospital major adverse cardiac and cerebrovascular events, graft occlusion, the postoperative blood loss and reexploration for bleeding were recorded. Of the 220 patients, 181 aspirin responders (82.3%) and 39 aspirin non-responders (17.7%) were defined. There were no significant differences in troponin I levels (ng/mL) between aspirin responders and aspirin non-responders: preoperative (0.04 +/- 0.08 vs 0.03 +/- 0.06; P = 0.56), postoperative 1 hr (0.72 +/- 0.87 vs 0.86 +/- 1.10; P = 0.54), 6 hr (2.92 +/- 8.76 vs 1.50 +/- 2.40; P = 0.94), 24 hr (4.16 +/- 13.44 vs 1.25 +/- 1.95; P = 0.52), 48 hr (2.15 +/- 7.06 vs 0.65 +/- 0.95; P = 0.64) and 72 hr (1.20 +/- 4.63 vs 0.38 +/- 0.56; P = 0.47). Moreover, no significant differences were observed with regard to in-hospital outcomes. In conclusion, preoperative aspirin resistance does not increase myocardial injury in patients undergoing off-pump coronary artery bypass surgery. Postoperative dual antiplatelet therapy might have protected aspirin resistant patients.

Anesthetic management of a patient with Mounier-Kuhn syndrome undergoing off-pump coronary artery bypass graft surgery: A case report / 대한마취과학회지

Mounier-Kuhn-syndrome patients have markedly dilated trachea and main bronchi due to an atrophy or absence of elastic fibers and thinning of smooth muscle layers in the tracheobronchial tree. Although this syndrome is rare, airway management is challenging and general anesthesia may produce fatal results. However, only a few cases have been reported and this condition is not widely known among anesthesiologists. We present the case of a tracheobronchomegaly patient undergoing an emergency off-pump coronary artery bypass. Although the trachea was markedly dilated with numerous tracheal diverticuli, there was an undilated 2 cm portion below the vocal cords found on the preoperative CT. Under a preparation of extracorporeal membrane oxygenation, we intubated and placed the balloon of an endotracheal tube (I.D. 9 mm) at this portion, and maintained ventilation during the operation. This case showed that a precise preoperative evaluation and anesthetic plan is essential for successful anesthetic management.

Influence of the Head Posture on Central Venous Catheter Position during Right Subclavian Catheterization / 대한마취과학회지

BACKGROUND: Confirmation of central venous catheter position with chest X-ray is recommended, but frequently omitted in clinical practice. It was suggested that the head posture during right subclavian catheterization affects the incidence of catheter malposition in infants. We evaluated the influence of the head posture on catheter position during right subclavian catheterization in adults. METHODS: Two-hundred and seventy four patients scheduled for thoracic or neuro-surgery requiring central venous catheterization were enrolled. Patients were divided into 3 groups depending on the head posture during catheter insertion: the neutral group (n = 109), the turn away group (n = 72), and the turn toward group (n = 93). The catheter position was confirmed with postoperative chest X-ray. RESULTS: Central venous catheterization was failed in 5 patients. There were no differences in the incidence of catheter malposition and the complications among the 3 groups. CONCLUSIONS: The head posture during right subclavian catheterization did not affect catheter malposition and immediate complication rates.

The Efficacy of Epinephrine-Containing Test Dose during Propofol-Nitrous Oxide Anesthesia with High Dose Fentanyl / 대한마취과학회지

BACKGROUND: The aim of this study is to determine the effect of high dose fentanyl on the test dose containing 15microgram epinephrine during propofol anesthesia. METHODS: One hundred patients with ASA physical status 1 were randomized to receive 2 mg/kg propofol with or without 10microgram/kg fentanyl at the induction of anesthesia (n = 50 each). Anesthesia was maintained with propofol 8 mg/kg/h and 67% nitrous oxide in oxygen. Each group of patients were further divided into a test dose group receiving 1.5% lidocaine 3 ml plus epinephrine 15microgram or a saline group receiving 3 ml of isotonic saline (n = 25 each). Heart rate (HR) and systolic blood pressure (SBP) were monitored for 4 min after intravenous injection of the study drugs. RESULTS: In the propofol and the propofol-fentanyl group, the intravenous injection of the test dose produced a HR increase > or = 20 bpm (conventional HR criterion) in 25 and 23 out of the total 25 patients, respectively. Therefore, in the propofol-fentanyl group, sensitivity, specificity, positive predictive value, and negative predictive value were 82%, 100%, 100%, and 92.6%. According to the modified HR criterion (HR increase > or = 10 bpm), all the values were 100%. All patients receiving test dose developed SBP increase > or = 15 mmHg. CONCLUSIONS: Our results indicate that both HR increase > or = 10 bpm or SBP increase > or = 15 mmHg are clinically applicable during propofol-nitrous oxide anesthesia with 10microgram/kg fentanyl.

Could Modified Thromboelastogram Assess Platelet Inhibition by Aspirin in off Pump Coronary Artery Bypass Surgical Patients and Healthy Volunteers? / 대한마취과학회지

BACKGROUND: Thromboelastogram (TEG) is regarded as a method by which coagulation can be measured during surgery. Off pump coronary artery bypass (OPCAB) surgical patients are routinely placed on aspirin. But conventional TEG could not detect platelet dysfunction by antiplatelet agent. We used modified TEG (addition of heparin and platelet agonists) to determine whether this modified TEG could assess the platelet dysfunction by aspirin in OPCAB surgical patients and healthy volunteers. METHODS: After institutional review board approval and consent, platelet function of 10 OPCAB patients (group 1) and 10 healthy subjects (group 2: before aspirin, group 3: after aspirin) were measured using modified TEG. In each group, TEG parameters (R, K time and MA) were analyzed using paired t-test and one way ANOVA was used to determine the difference between groups. RESULTS: In group 1 (OPCAB patients) and group 2 (healthy subjects, before aspirin), the R and K time were increased significantly with the addition of heparin and then decreased subsequently with the platelet agonists (ADP or collagen) in the presence of anticoagulation (heparin). MA showed a decrease in both groups. This compares with no significant difference in all parameters in group 3 (healthy subjects, after aspirin) with the addition of heparin, ADP and collagen. There were no significant differences in each TEG parameter between groups. CONCLUSIONS: This study suggested that aspirin medication obliterated the effect of anticoagulation and platelet agonists in modified TEG. However modified TEG does not provide a comprehensive and sensitive reflection of platelet inhibition by aspirin. TEG should be supplemented by other methods of platelet function assessment.

Hemodynamics of Milrinone and Low-Dose Vasopressin Infusion during OPCAB / 대한마취과학회지

BACKGROUND: AVP (arginine vasopressin) shows unique hemodynamic characteristics, as a vasopressor. AVP has been tried in many cathecholamine refractory vasodilatory situations, and sometimes resulted in effective hemodynamic improvement. In this study, we hypothesized that low dose AVP infusion could recover the decreased SVR (systemic vascular resistance) induced by milrinone infusion with minimal effect on PVR (pulmonary vascular resistance). METHODS: Sixteen patients undergoing OPCAB participated in this study. After a loading dose milrinone was infused, low dose vasopressin infusion was started and titrated until the systemic blood pressure increased by 20%. During the study, hemodynamic factors including pulmonary capillary wedge pressure and cardiac output were measured using a continuous thermodilution technique with a Swan-Ganz catheter. RESULTS: Milrinone infusion reduced both SVR and PVR. And vasopression infusion increased SVR, but show relatively less effect on PVR. CONCLUSIONS: Low-dose vasopressin infusion could be used to recover the SVR decrease caused by milirinone infusion with little effect on PVR.

Use of Preoperative Transthoracic Echocardiography to Predict the Prognosis after Off-Pump Coronary Artery Bypass Grafting / 대한마취과학회지

BACKGORUND: Echocardiography is usually performed for preoperative cardiac evaluation before coronary bypass graft surgery. if the variables detected by this noninvasive method could predict the outcome of the off-pump coronary bypass surgery (OPCAB), it would be very helpful. The purpose of this study is the evaluation of preoperative transthoracic echocardiographic findings as the predictor of OPCAB outcome. METHODS: We evaluated the relationships between preoperative variables identified by the transthoracic echocardiography and postoperative outcomes. RESULTS: Among the doppler findings trans-mitral flow shows no relationship with the postoperative outcome. But, left ventricular mass had the predictability of postoperative time of extubation, iCU stay, and hospital stay. CONCLUSiONS: Left ventricular mass can be used to predict the outcome after OPCAB and There are the need of further study to find out the reason the left ventricular mass show relationship with the postoperative outcome.