Lethal pulmonary thromboembolism misdiagnosed as pneumonia: A case report / 대한마취과학회지

Although pulmonary thromboembolism (PTE) is not rare, unfortunately for anesthesiologists, the signs and symptoms of PTE are unreliable and nonspecific. PTE is a potentially lethal condition without an accurate diagnosis and prompt treatment. We report a case of PTE misdiagnosed as simple pneumonia. A 60-year-old female, not receiving prophylactic anticoagulant therapy, underwent elective surgery for a left proximal tibial fracture. During induction of general anesthesia, a temporary bronchospasm occurred and subsided quickly. Because vital signs were stable and patient monitoring was normal, we did not identify a serious hypercarbic condition. After surgery, a massive hemoptysis occurred and the patient expired due to cardiopulmonary collapse. According to autopsy, the cause of death was a PTE originating in deep vein thrombosis.

The Effects of Low Molecular Weight Hydroxyethyl Starch Replacement Solution in Acute Normovolemic Hemodilution / 대한마취과학회지

BACKGROUND: Unlikely crystalloid, hydroxyethyl starch (HES) solution as a replacement fluid during acute normovolemic hemodilution (ANH) compromises hemodilution-mediated hypercoagulability. However a new HES [130/0.4] preparation may influence hemostasis minimally due to an improved molecular distribution in plasma. This study was designed to estimate the effect of low molecular weight HES solutions (HES [70/0.55] and HES [130/0.4]) during ANH. METHODS: Twenty healthy patients scheduled for spine surgery were randomly enrolled in HES 70 and HES 130 groups. All patients underwent moderate ANH before the induction of anesthesia. While whole blood (20 ml/kg) was being procured, blood deficits were replaced with the same volume of the respective HES solutions. Hematocrit, platelet count, plasma fibrinogen concentration, ionized calcium level, and factor VIII activity were assayed and thrombelastography (TEG) was performed before and after ANH. Statistical tests were conducted to determine the effect of each HES solution. RESULTS: Hematocrit, platelet count, plasma fibrinogen concentration and factor VIII activity were lower than baseline in each group after ANH. According to TEG findings, MA was lower in both groups but R shortened and alpha enhanced in the HES 130 group alone. Comparisons between the HES 70 and HES 130 groups showed that hematocrit, R, alpha and MA changes during ANH differed significantly between the two (repectively, P = 0.019, 0.043, 0.023 and 0.019). CONCLUSIONS: HES [130/0.4] solution administered for ANH impairs the hemostatic system to a lesser extent than HES [70/0.55] solution. However, because the volume effect of HES [130/0.4] solution persists for a few hours, a chance of hypovolemia remains during ANH.

The Influences of 6% HES (130/0.4) Solution on Hemostasis / 대한마취과학회지

BACKGROUND: Hydroxyethyl starches (HES) solutions are the most commonly used colloids for treating hypovolemia and expanding plasma, but they compromise platelet function and reduce the level of coagulation factors. As opposed to other HES solutions, 6% HES (130/0.4) solution may influence hemostasis minimally due to its low mean molecular weight and degree of substitution. This study was designed to establish the safety of HES (130/0.4) infusion in the presence of massive blood loss. METHODS: Twelve healthy adult patients scheduled for spine surgery were enrolled in this study. Before the induction of general anesthesia, all patients underwent acute normovolemic hemodilution (ANH), which was independent of surgical stress and other confounding factors. While approximately 30% of the estimated blood volume was procured, the blood deficit was replaced with the same volume of 6% HES (130/0.4) solution. Hematocrit, platelet count, factor VIII activity and plasma fibrinogen concentration were determined and thrombelastography was performed to evaluate the hemodilution effect and hemostatic impairment before and after ANH. Statistical testing was conducted to analyze the effect of HES on hemostasis. RESULTS: Hematocrit, platelet count, factor VIII activity and plasma fibrinogen concentrations decreased significantly (P < 0.05 respectively) after the ANH. On comparing pre-ANH and post-ANH thrombelastographic findings, the R time was shortened (P = 0.045), the alpha angle increased (P = 0.01) and MA decreased (P = 0.003) significantly. CONCLUSIONS: Summarizing, little effect was observed on the hemostatic system when 20 ml/kg of 6% HES (130/0.4) solution was infused. HES (130/0.4) solution as used to maintain normovolemia during ANH may be free from bleeding risk.

Selective Cerebral Perfusion Through the Right Axillary Artery for Aortic Arch Replacement: A Case Report / 대한마취과학회지

To prevent ischemic brain damage, different techniques, such as, the deep hypothermic circulatory arrest (DHCA), selective antegrade cerebral perfusion (SACP) and retrograde cerebral perfusion (RCP), have been widely used in patients undergoing aortic arch replacement. However, these techniques have been reported to have potential hazards, and in these techniques. Coagulation defect, atheremboli and cerebral edema are known to lead to neuropsychological deficits after cardiopulmonary bypass (CPB). We believe that cerebral perfusion through the right axillary artery, modification of SACP, is the safer, more physiologic and feasible technique. Selective cerebral perfusion (flow: 8-10 mL/kg/min) by right axillary artery cannulation during deep hypothermic arrest was applied in two male patients; a 71-year-old male with ascending aortic aneurysm and a 76-year-old male with aortic dissection (Stanford type A). Both operations were successful and no neurologic complication occurred postoperatively.

Coagulopathy Detected with a Thrombelastography during ANH after Induction of General Anesthesia: A case report / 대한마취과학회지

Thrombelastography (TEG) performed by an anesthesiologist provides a rapid assessment of coagulation at the bedside. TEG analyzing coagulation status of native whole blood is a more accurate test with a relatively good sensitivity and specificity than PT and aPTT. We experienced an unexpected coagulopathy during the perioperative period. The case was a 47-year-old male patient with blood type O who underwent elective spine surgery. Perioperative coagulation tests (PT, aPTT, BT, CT, etc.) were within normal limits. Anesthesia was induced with propofol 90 mg, vecuronium 8 mg and alfentanil 0.5 mg and maintained with 1.0 1.5 vol% enflurane and 50% N2O in O2. Then we performed acute normovolemic hemodilution (ANH) with monitoring pre- and post-hemodilutional TEG. Hemostasis was revealed as abnormal by a pre-hemodilution TEG (CI = -11.06) and post-hemodilution TEG (CI = -13.06). We managed this coagulopathy with blood components and drugs on the basis of a follow-up TEG so that abnormal hemostasis and TEG findings improved (CI = -4.35). We report a case where undetected coagulopathy was revealed and treated successfuly with TEG.

The Changes of Coagulation State among ABO Blood Types during Acute Normovolemic Hemodilution / 대한마취과학회지

BACKGROUND: Improvement of coagulation function by acute normovolemic hemodilution (ANH) is well evidenced in modern medical practice. It has been reported that there are fixed differences in the plasma concentrations of von Willebrand factor and factor VIII according to ABO blood types. Therefore, the changes of coagulation state among ABO blood types during ANH are expected but have not yet been studied. This study was designed to establish the changes of coagulation state among ABO blood types during ANH by intraoperative thrombelastography (TEG). METHODS: Fifty one healthy adult patients scheduled for spine surgery were enrolled in this study. All patients were grouped by ABO blood types and underwent ANH after the induction of general anesthesia. While autologous blood (25% of EBV) was procured, warmed 0.9% saline, 3 times the blood volume deficit, was infused to maintain normovolemia. Platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT), factor VIII activity and TEG were performed to evaluate coagulation state before and after ANH. Statistical analysis was conducted to determine the dilutional effects and intergroup differences. RESULTS: Improvement of coagulation function after ANH was visible only by TEG, and not by PT, APTT or factor VIII activity. Fourteen of fifteen patients with type O blood showed decreased factor VIII activity to under the normal limit after ANH. In patients with blood type O, changes of APTT (P = 0.093, P = 0.086) and factor VIII activity (P = 0.001, P = 0.004) during ANH were remarkable in comparison with blood type B and AB. CONCLUSIONS: ANH enhances coagulation function evaluated by means of TEG. No difference was observed in terms of the changes of coagulation state among ABO blood types during ANH. However, ANH should be instituted cautiously in patients with type O blood because there is a possibility of impairing factor VIII activity.

The Effects of N2O on Intubation Not Using Muscle Relaxant with Propofol-Alfentanil / 대한마취과학회지

BACKGROUND: The combination of propofol and alfentanil for nonrelaxant intubation produces hypotension and bradycardia. N2O, a commonly used inhaled anesthetic, has been known to augment the anesthetic depth in propofol anesthesia. Conversely, N2O was reported to increase the incidences of opioid-induced cough and rigidity. This study was designed to evaluate the effect of additional N2O on propofol requirement and intubating conditions. METHODS: Eighty healthy premedicated female patients were divided into N2O group (n = 40) and non-N2O group (n = 40). In each group, they were randomly assigned to four subgroups according to the propofol dose (1.0-2.5 mg/kg). With or without N2O (FiN2O = 0.5), propofol and 30mug/kg of alfentanil were administered during the induction of anesthesia. Expired concentrations of N2O were measured. Intubation was the attempted and intubating condition was scored (0-6). Incidences of cough and rigidity were also recorded. Dose of propofol for smooth intubation (score > 5) was analyzed and compared between groups. The conditions for smooth intubation were analyzed with variables (expired concentration of N2O, dose of propofol, age, incidences of hypotension, bradycardia, cough and rigidity) by logistic regression. RESULTS: The expired concentration of N2O was 33.0-3.8%. Propofol ED50 for smooth intubation was 1.67 mg/kg (1.26-2.19) in the N2O group and 2.27 mg/kg (1.78-3.47) in the non-N2O group. A smooth intubating condition was correlated well with increased concentrations of N2O and doses of propofol and inversely correlated with incidences of cough and rigidity. However, we failed to prove a significant difference in incidences of hypotension, bradycardia, cough and rigidity between the two groups. CONCLUSIONS: We cannot reduce the propofol requirement for smooth intubation without relaxant by using N2O. The success rate of intubation was increased by additional N2O.

The Effects of Alfentanil on Mother and Neonate during the Induction of General Anesthesia for a Cesarean Section / 대한마취과학회지

BACKGROUND: During general anesthesia for a cesarean section, light depth of anesthesia frequently leads to maternal awareness and pain responses. The aim of this study was to evaluate the effects of alfentanil on the mother and neonate during a cesarean section. METHODS: Forty four parturients undergoing general anesthesia for an elective cesarean section were enrolled in this study. General anesthesia was induced with propofol 2 mg/kg and succinylcholine 1.5 mg/kg after an intravenous injection of normal saline 0.02 ml/kg for the control group or alfentanil 10microgram/kg for the alfentanil group. After tracheal intubation, anesthesia was maintained with O2 (2 L/min)-N2O (2 L/min)-isoflurane (0.5% end tidal). Mean blood pressure (MBP), heart rate, bispectral index (BIS) and maternal pain responses by an isolated forearm technique were measured every 1 min until delivery. Apgar scores of neonates were measured at 1 min and 5 min after delivery. RESULTS: There were no differences between groups in the MBP, BIS or maternal pain responses. However heart rates were lower in the alfentanil group than in the control group (P = 0.017). CONCLUSIONS: The supplemental administration of alfentanil 10microgram/kg can attenuate the changes in maternal heart rate during general anesthesia for a cesarean section without neonatal Apgar score decline.