Hemostatic capability of ultrafiltrated fresh frozen plasma compared to cryoprecipitate.

This in vitro study evaluated the potential hemostatic effect of fresh frozen plasma (FFP) ultrafiltration on clotting factors, coagulation parameters, and plasma properties. ABO-specific units of FFP (n = 40) were prepared for the concentrated FFP and cryoprecipitate. Plasma water was removed from FFP by ultrafiltration using a dialyzer with a pump running at a 300 mL/min. The aliquot of each concentrated FFP after 50, 100, 200, and 250 mL of fluid removal were measured the standard coagulation assay, clotting activity, and plasma properties to compare those parameters of cryoprecipitate. Concentrated FFP contained 36.5% of fibrinogen in FFP with a mean concentration of 7.2 g/L, lower than the cryoprecipitate level. The levels of factor VIII (FVIII), von Willebrand factor (VWF):antigen (Ag), and VWF:ristocetin cofactor (RCo) were also lower in concentrated FFP, whereas the levels of factor V, factor IX, factor XIII, antithrombin and albumin was higher in concentrated FFP. Maximum clot firmness (MCF) in thromboelastometry was approximately one-half of that in cryoprecipitate. Although the levels of VWF:Ag, VWF:RCo, and FVIII differed depending on the ABO blood types, fibrinogen levels, and MCF were not significantly different among the ABO blood groups in FFP and concentrated FFP.

Effects of room temperature and cold storage on the metabolic and haemostatic properties of whole blood for acute normovolaemic haemodilution.

BACKGROUND: Acute normovolaemic haemodilution (ANH), as a blood-conservation technique, avoids the need for allogeneic blood transfusions. The historic practice of cold-storing type-O whole blood (WB) in military fields popularised the transfusion of refrigerated WB to treat acute bleeding. In this study, we compared the effects of room temperature (RT) and refrigeration up to 24 hours on the coagulation properties of WB for ANH. MATERIALS AND METHODS: Each WB sample, collected from 12 male volunteers, was divided into two parts, one stored at RT and the other refrigerated for 24 hours. Complete blood counts (CBC), blood gas levels, and coagulation profiles were measured, and rotational thromboelastometry (ROTEM) measurements were performed at the initial collection time point (baseline) and at 6, 12, and 24 hours after initial collection. RESULTS: The preservation of platelet aggregation response induced by arachidonic acid and adenosine diphosphate was better in cold-stored WB compared to that in RT-stored WB. The platelet aggregation response induced by thrombin receptor-activating peptide 6 was significantly decreased in all samples after 24 hours of storage when compared with that at baseline. The lactate levels in WB stored at RT increased significantly after 6 hours of storage compared to that of cold-stored samples. There were no significant differences in CBC, coagulation parameters, and ROTEM variables between the cold-stored and RT-stored WB samples. CONCLUSION: WB for ANH stored in the refrigerator showed better metabolic characteristics after 6 hours of storage and better aggregation response after 12 hours of storage than WB stored at RT.

Storage-Related Changes in Autologous Whole Blood and Irradiated Allogeneic Red Blood Cells and Their Ex Vivo Effects on Deformability, Indices, and Density of Circulating Erythrocytes in Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass.

OBJECTIVES: Blood-processing techniques and preservation conditions cause storage lesions, possibly leading to adverse outcomes after transfusion. The authors investigated the metabolic changes and deformability of red blood cells (RBCs) during storage and determined the effect of storage lesions on circulating RBCs during cardiac surgery. DESIGN: Prospective study. SETTING: Tertiary care center affiliated with a university hospital. PARTICIPANTS: Adults who underwent elective cardiac surgery requiring cardiopulmonary bypass. INTERVENTIONS: The authors collected aliquots of autologous and irradiated allogeneic RBCs and blood samples from seven patients who received autologous whole blood and nine patients who received irradiated allogeneic RBCs before incision (baseline), at the start and end of cardiopulmonary bypass, and at completion of surgery. MEASUREMENTS AND MAIN RESULTS: The authors analyzed RBC deformability, erythrocyte indices, and density distribution to evaluate blood banking-induced alterations of autologous and allogeneic RBCs and changes in circulating RBCs in recipients, after blood transfusion. Time-dependent biochemical changes and significant decreases in deformability during storage occurred in both groups; however, homologous RBCs had significantly lower deformability than autologous RBCs. Trends in mean corpuscular volume and mean corpuscular hemoglobin concentration differed in both groups. In the homologous transfusion group, during cardiac surgery, RBC deformability, mean corpuscular volume, and mean corpuscular hemoglobin concentration showed significant changes compared with baseline values, and a greater number of denser subpopulations was observed at surgery completion. CONCLUSIONS: Blood-processing techniques contribute to storage lesions, suggesting that transfusion of autologous whole blood, rather than allogeneic RBCs, could maintain the ability of circulating RBCs to deform and lead to potentially better transfusion outcomes.

Refractory ventricular arrhythmias during aortic valve replacement and cardiac artery bypass requiring 16 attempts of electrical cardioversion: a case report.

BACKGROUND: We report a patient in whom we failed to suppress ventricular fibrillation (VF) using nifekalant but succeeded using amiodarone during cardiopulmonary bypass (CPB). CASE PRESENTATION: A 65-year-old male with hemodialysis complained of dyspnea and was diagnosed with aortic valve stenosis and angina pectoris; he was opted for elective aortic valve replacement. When the aortic forceps were declamped during CPB, immediate VF was observed; several attempts of electrical cardioversion (EC) with lidocaine and landiolol and three administrations of nifekalant were temporarily effective. However, the rhythm subsequently changed to torsades de pointes. We administered 2 g of magnesium sulfate followed by three doses of amiodarone and initiated continuous infusion. Furthermore, we initiated the pacemaker and intra-aortic balloon pumping. These procedures seemed to be effective; the sinus rhythm was sustained until the end of the surgery. CONCLUSION: We experienced a cardiac surgery requiring 16 EC attempts to terminate the life-threatening arrhythmias using amiodarone.

Thromboelastometry and a hemostasis management system are most beneficial for guiding hemostatic therapy in cardiac surgery patients with a EuroSCORE II of ≥1.83%: a randomized controlled two-step trial.

PURPOSE: We evaluated the efficacy of hemostatic therapy based on point-of-care (POC) testing in patients undergoing cardiac surgery. METHODS: This was a single-institution, prospective, randomized, double-blinded study. In step 1, 90 patients scheduled for elective cardiac surgery underwent complete blood count and fibrinogen measurements at baseline, after cardiopulmonary bypass (CPB) initiation (CPB start), just after CPB end, and in the intensive care unit (ICU). In step 2, 72 patients scheduled for elective cardiac surgery underwent conventional laboratory coagulation tests (control group) or POC coagulation tests (POC group). Transfusions were prepared using the fibrinogen and platelet values at mainly "CPB start" for the control group, and using the ROTEM values at mainly "CPB end" for the POC group. Consequently, the step 2 patients were divided into high- and low-risk subgroups based on the EuroSCORE II by logistic regression analysis; transfusion data and bleeding volumes were compared between the control and POC groups within the high- and low-risk subgroups. RESULTS: In step 1, all blood components were significantly decreased at CPB start compared with baseline, and platelet and fibrinogen levels remained almost constant from CPB start to end. In step 2, the transfusion rates and perioperative bleeding volumes did not significantly differ between the control and POC groups. Subgroup analysis suggested that only the high-risk subgroup significantly differed regarding perioperative red blood cell transfusion and total bleeding volume in the ICU. CONCLUSIONS: POC testing is beneficial for cardiac surgery patients with a EuroSCORE II of ≥1.83%.

Changes in Erythrocyte Morphology at Initiation of Cardiopulmonary Bypass Without Blood Transfusion Were Not Associated With Less Deformability During Cardiac Surgery.

OBJECTIVES: During cardiac surgery, circulating red blood cells (RBCs) are at risk of exposure to environmental factors during extracorporeal circulation and transfusion of stored RBCs. For this study, the authors observed morphological differences, deformability, density distribution, and erythrocyte indices of RBCs during cardiac surgery with cardiopulmonary bypass (CPB). DESIGN: Prospective study. SETTING: Tertiary care center affiliated with a university hospital. PARTICIPANTS: Adults who underwent elective cardiac surgery requiring CPB. INTERVENTIONS: Blood samples were obtained from 13 patients before incision (baseline), at initiation of CPB, after separation from CPB, and at completion of surgery. MEASUREMENTS AND MAIN RESULTS: The morphological index (MI) in RBCs using light microscopy and the maximum deformability index (DImax) using an ektacytometer were evaluated. In addition, the fractionation of RBCs and erythrocyte indices were measured. The MI at initiation of CPB was significantly higher without blood transfusion compared with baseline, although the DImax did not significantly decrease simultaneously. The DImax after separation from CPB and at completion of surgery were significantly lower than that at baseline. This lowered DImax was accompanied by a significantly reduced mean corpuscular volume and elevated mean corpuscular hemoglobin concentration compared with baseline. Dense RBC subpopulations increased after initiating CPB. The MI after separation from CPB and at completion of surgery partially recovered. Administered stored RBCs showed a high MI and the lowest DImax. CONCLUSIONS: Morphological changes at initiation of CPB are considered potentially reversible transformations without loss of the membrane surface area and do not have a significant effect on the DImax. A decrease in deformability likely is due to transfusion of stored RBCs.

Effects of crystalloids and colloids on microcirculation, central venous oxygen saturation, and central venous-to-arterial carbon dioxide gap in a rabbit model of hemorrhagic shock.

OBJECTIVE: The effects of hydroxyethyl starch (HES) on microcirculation, central venous oxygen saturation (ScvO2), and the central venous-to-arterial carbon dioxide gap (dCO2) are studied in a rabbit model of hemorrhagic shock for elucidating the advantages and drawbacks of resuscitation with HES compared with crystalloids. METHODS: An ear chamber and sublingual mucosa were used to examine blood vessels by intravital microscopy. Hemorrhagic shock was induced by removing nearly half of the blood volume. Twenty-two rabbits received 20 mL of HES by intravenous infusion immediately after bloodletting. Additional HES was then administered intravenously to a total volume of 100 mL. The other 22 rabbits (control) were intravenously given 40 mL of normal saline solution (NSS), followed by additional NSS to a total volume of 200 mL, administered under the same conditions as HES. RESULTS: After the infusion, the vessel density and perfusion rate of the sublingual microcirculation recovered in the HES group. The arteriolar diameter, blood flow velocity, and blood flow rate of the ear microcirculation were maintained in this group, and microcirculatory failure did not develop. In the NSS group, however, all 5 of the aforementioned measured variables were significantly smaller than those in the HES group after the completion of infusion. The recovery of ScvO2 and dCO2 to the respective baseline values was significantly better in the HES group than in the NSS group. CONCLUSION: Intravenous infusion of HES effectively maintains adequate tissue oxygenation and perfusion in hemorrhagic shock.

Dose-dependent effect of stored-blood transfusions on recipient red blood cell indices, deformability and density.

We prospectively studied the dose-dependent effect of transfused stored red blood cells (RBCs) on recipient RBC indices, deformability and cell density in 10 patients administered stored RBCs for blood transfusion during general surgery. There were dose-dependent decreases in mean corpuscular volume and increases in mean corpuscular haemoglobin concentration after completion of 4- and 6-unit stored RBC transfusions. The amount of dense populations increased proportionately with the amount of stored RBCs transfused. The maximal deformability index value was significantly and dose-dependently decreased, suggesting that hemodynamic blood flow, especially the microcirculation may be impaired in patients who receive large amounts of stored RBCs.

Introduction of thromboelastometry-guided administration of fresh-frozen plasma is associated with decreased allogeneic blood transfusions and post-operative blood loss in cardiopulmonary-bypass surgery.

BACKGROUND: Cardiac surgery is frequently associated with excessive blood loss requiring multiple blood transfusions which are, in turn, associated with increased morbidity and mortality. We evaluated the effectiveness of rotational thromboelastometry (ROTEM®)-guided administration of fresh-frozen plasma (FFP) with regards to blood loss, transfusion requirements, and major post-operative complications. MATERIALS AND METHODS: Coagulation management in 68 prospective patients undergoing cardiac surgery with cardiopulmonary bypass was based on a treatment algorithm guided by ROTEM® measurements. The primary end-point was blood loss at 24 hours after surgery. Secondary end-points were: (i) need for allogeneic blood products after cardiopulmonary bypass and 24 hours post-operatively, and (ii) post-operative complications until discharge. The results were compared with those of a retrospective, control group of 69 patients who received empirical coagulation management before implementation of the ROTEM®-guided algorithm. RESULTS: Although patients with significantly lower haemoglobin levels received less packed red blood cells (PRBC) (840 vs 1,120 mL; p=0.031) and FFP (480 vs 720 mL; p=0.007) after introduction of the ROTEM® algorithm, the intra-operative blood loss and post-operative haemoglobin levels were similar in the ROTEM® and the retrospective control groups. In addition to significantly reduced blood loss and decreased requirements for PRBC (30.8 vs 62.3%; p<0.001) and FFP (25.0 vs 56.5%; p<0.001), the amounts of PRBC (315 vs 840 mL; p<0.001) and FFP (480 vs 840 mL; p=0.001) received during the first 24 hours after surgery were significantly reduced in the ROTEM® group, as was the duration of post-operative hospitalisation. DISCUSSION: Compared with empirical treatment, timely ROTEM®-guided FFP administration during cardiac surgery can reduce not only overall blood product use and blood loss but also the duration of hospitalisation.

Association Between Platelet Count and Postoperative Blood Loss in Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass and Fresh Frozen Plasma Administration Guided by Thromboelastometry.

BACKGROUND: Coagulopathy after cardiopulmonary bypass (CPB) is caused by multiple factors, including reduced coagulation factors and a low platelet count.Methods and Results:In this study, we undertook a post hoc analysis to identify factors associated with increased postoperative blood loss in 97 patients undergoing cardiac surgery with CPB, with fresh frozen plasma administered according to a ROTEM-guided algorithm. We identified 24 patients for the top quartile of postoperative blood loss, >528 mL and defined as having excessive blood loss. Using Spearman's rank correlation test and multivariable linear regression, we reanalyzed the participants' demographic, surgical and anesthetic variables, laboratory test results, blood loss, and transfusion data. Univariate analysis indicated that patients who experienced higher postoperative blood loss received a significantly higher heparin dose, had a higher requirement for fresh frozen plasma transfusion during surgery, and had a significantly lower hematocrit and platelet count at the end of surgery compared with patients without excessive blood loss. Multivariate analysis showed that platelet count at the end of surgery (odds ratio 0.780, 95% confidence interval 0.629-0.967; P=0.024) was an independent factor for excessive blood loss. CONCLUSIONS: Low platelet count at the end of surgery was associated with excessive postoperative bleeding during cardiac surgery with CPB.

Changes in heparin dose response slope during cardiac surgery: possible result in inaccuracy in predicting heparin bolus dose requirement to achieve target ACT.

INTRODUCTION: The substantial interpatient variability in heparin requirement has led to the use of a heparin dose response (HDR) technique. The accuracy of Hepcon-based heparin administration in achieving a target activated clotting time (ACT) using an HDR slope remains controversial. METHODS: We prospectively studied 86 adult patients scheduled for cardiac surgery requiring cardiopulmonary bypass. The total dose of calculated heparin required for patient and pump priming was administered simultaneously to achieve a target ACT of 450 s for HDR on the Hepcon HMS system. Blood samples were obtained after the induction of anesthesia, at 3 min after heparin administration and after the initiation of CPB to measure kaolin ACT, HDR slope, whole-blood heparin concentration based on the HDR slope and anti-Xa heparin concentration, antithrombin and complete blood count. RESULTS: The target ACT of 450 s was not achieved in 68.6% of patients. Compared with patients who achieved the target ACT, those who failed to achieve their target ACT had a significantly higher platelet count at baseline. Correlation between the HDR slope and heparin sensitivity was poor. Projected heparin concentration and anti-Xa heparin concentration are not interchangeable based on the Bland-Altman analysis. CONCLUSION: It can be hypothesized that the wide discrepancy in HDR slope versus heparin sensitivity may be explained by an inaccurate prediction of the plasma heparin level and/or the change in HDR of individual patients, depending on in vivo factors such as extravascular sequestration of heparin, decreased intrinsic antithrombin activity level and platelet count and/or activity.

[Empathy to be Shown by Pharmacists toward Home Patients - Initiatives Undertaken by Pharmacists to Promote the Proper Use of Pharmaceutical Products].

Separation of medical and dispensary services has taken root in Japan as a healthcare system;8 00 million prescriptions have been issued, and 70% of medical institutions now participate in this practice. Additionally, discussions are ongoing regarding patient-oriented family pharmacies from a"back-to-basics"perspective of the separation drug dispensing from medical practice. Through a series of such discussions, the Ministry of Health, Labour and Welfare published a paper entitled"Vision for Pharmacies Working for Patients"with a focus on 3 functions to be implemented by family pharmacists and pharmacies. In home healthcare, there have been cases so far, as shown in the Vision paper, of suggestions from and initiatives taken by pharmacists that have helped improve patient home care services. This paper explores home care-related initiatives undertaken by our pharmacy, including 2 cases in which our pharmacists intervened to prevent duplicate prescriptions and promoted adherence to a medication regimen, having noticed a change in a patient's physical abilities caused by the presence of drug residues. Our pharmacists will inform other relevant professionals about this issue. The study discusses our experience, which may help provide insight on the ideal roles of pharmacists in this time of partnerships among professionals.

In vitro and in vivo effects of hemodilution on kaolin-based activated clotting time predicted heparin requirement using a heparin dose-response technique.

PURPOSE: The heparin dose-response (HDR) technique is based on activated clotting time (ACT) response to a fixed-dose heparin bolus, which varies substantially among patients. It is unclear, however, whether hemodilution-associated reductions in coagulation and anticoagulation factors affect the HDR slope. METHODS: For in vitro hemodilution, aliquots of whole blood from healthy volunteers were diluted 9:1 and 8:2 v/v with normal saline. For in vivo hemodilution, a prospective observational study was performed on 46 patients who underwent elective cardiovascular surgery with or without cardiopulmonary bypass. HDR slope, antithrombin (AT) activity, complete blood count, and other coagulation parameters were compared after induction of anesthesia and after hemodilution with 500 ml of intravenous fluid. RESULTS: In vitro 10 and 20 % hemodilution significantly increased the HDR slope relative to baseline, reducing the heparin requirement. Hemodilution of heparinized samples significantly prolonged ACT, whereas there was no significant change in non-heparinized blood. The percent changes in fibrinogen and AT activity were significantly greater at 20 % than those of the other coagulation variables. In vivo, hemodilution significantly increased the HDR slope and reduced heparin requirement. The percent change in fibrinogen due to hemodilution was significantly greater than the change in AT activity. Target ACTs of 300 and 450 s were not achieved in 83.3 and 53.8 % of patients, respectively. CONCLUSION: In vitro and in vivo hemodilution significantly increased the HDR slope and reduced the requirement for heparin. In vitro, the HDR slope did not change in parallel but became steeper, depending on the degree of hemodilution.

Safety of lipid emulsion in very low-birthweight infants according to cytokine level.

BACKGROUND: The aim of this study was to verify whether lipid emulsion treatment aggravates infection and inflammation in very low-birthweight (VLBW) infants. STUDY DESIGN: Very low-birthweight (<1500 g) infants born at <32 weeks gestational age between October 2013 and October 2014 at Dokkyo Medical University Hospital (Mibu, Tochigi, Japan) were treated with or without i.v. nutrition with a lipid emulsion. Infants were excluded who had congenital abnormalities, could not receive i.v. nutrition because of poor general condition, or on physician decision. Lipid emulsion with purified soybean oil was initiated at 0.5 g/kg/day on postnatal day 1. The dose was increased to 1 g/kg/day, and then to 1.5 g/kg/day (maximum dose). Blood tests were performed before (day 1) and after (day 8) initiation of lipid emulsion treatment. Interleukin (IL)-6, IL-8, monocyte chemotactic protein 1 (MCP-1), tumor necrosis factor-α (TNF-α), C-reactive protein (CRP), total bilirubin (T-Bil), direct bilirubin (D-Bil) and insulin were measured. Changes in respiratory condition, amount of oxygen used, and phototherapy duration were investigated. RESULTS: A total of 17 treated and 15 untreated VLBW infants were enrolled. IL-6, IL-8, MCP-1, TNF-α, CRP, T-Bil, D-Bil and insulin on days 1 and 8; respirator or surfactant use; amount of oxygen used; and phototherapy duration were not significantly different between the two groups. CONCLUSIONS: Lipid emulsion treatment did not increase inflammatory cytokine levels or aggravate respiratory disorders. Lipid emulsions, if proven safe, could be used to treat VLBW infants soon after birth, which may prevent extrauterine growth restriction and improve intellectual development prognosis.

[The Use of Thromboelastometry and Tranexamic Acid Reduces Blood Loss and Transfusion Requirements in Cardiac Surgery under Cardiopulmonary Bypass].

BACKGROUND: We evaluated whether using thromboelastometry and tranexamic acid influenced blood loss and transfusion requirements in cardiac surgery requiring cardiopulmonary bypass. METHODS: We perfomed a retrospective analysis examining perioperative coagulation results, and the transfusion requirements of concentrated red cells (CRCs), fresh frozen plasma (FFP) and platelet administration between 12 months before and 10 months after thromboelastometry and tranexamic acid had been introduced in our institution. We also recorded patients' demographic details, the surgery performed and patient outcomes. RESULTS: After the introduction of thromboelastometry and tranexamic acid, fewer units of CRC were transfused during surgery, and fewer patients required postoperative CRC transfusion. Intra- and postoperative FFP requirements were also reduced. Intraoperative blood loss, blood loss in the first 24 hr after surgery, and length of hospital stay were also reduced. CONCLUSIONS: The use of ROTEM and tranexamic acid can potentially reduce blood loss and transfusion requirements in cardiac surgery.

Reappearance of circulating heparin in whole blood heparin concentration-based management does not correlate with postoperative bleeding after cardiac surgery.

OBJECTIVE: The Hepcon Heparin Management System (HMS) facilitates administration of higher heparin and lower protamine doses, which may affect bleeding potential due to heparin rebound. The present study evaluated heparin rebound in patients for whom the Hepcon HMS was used to determine whether point-of-care tests detect residual heparin and residual heparin is associated with postoperative blood loss. DESIGN: Prospective study. SETTING: Tertiary care center affiliated with a university hospital. PARTICIPANTS: Adults undergoing elective cardiac surgery requiring cardiopulmonary bypass. INTERVENTIONS: In blood samples obtained at baseline, at 2 minutes, and at 1, 2, 4, 6, and 24 hours after heparin neutralization, heparin concentrations were measured using an automated chromogenic assay. Activated coagulation time (ACT), activated partial thromboplastin time (APTT), and thromboelastometry 2 hours after heparin neutralization also were examined in the last 22 study patients enrolled. MEASUREMENTS AND MAIN RESULTS: All 31 patients had measurable heparin levels 2 hours after protamine administration; 22 patients exhibited a primary failure to reverse heparin after protamine administration, and 9 patients had measureable heparin levels 2 hours after complete heparin reversal (ie, heparin rebound). The thromboelastometric variable, INTEM-CT:HEPTEM-CT ratio, correlated with heparin concentration (r=0.72), but ACT (r=-0.12), APTT (r=0.36), and whole blood heparin concentration, determined using the Hepcon HMS, did not. Peak heparin concentration (0.18±0.07 U/mL) at 4 hours was not correlated with mediastinal blood loss. CONCLUSION: Circulating heparin detected by the chromogenic assay was too low to be clinically significant based on postoperative bleeding, although all 31 patients had residual heparin or heparin rebound at 2 hours after protamine administration with use of the Hepcon HMS.

Current problems and working status of female anesthesiologists in Japan.

The rapid growth of the elderly population and the progress in surgical techniques in Japan have led to increased numbers of patients who undergo surgery. Anesthetics are essential for surgery. A survey conducted by the Japanese Society of Anesthesiologists showed that, during the past 10 years, the proportion of females among all the members has increased from 27 to 35 %, and the proportion of female councilors has risen from 3.9 to 6.7 %. However, the conditions of full-time employment remain inadequate for female physicians. Therefore, many female physicians in their 30s or older do not work as anesthesiologists. To support female anesthesiologists and their vital roles in surgical diagnosis and treatment, return-to-work assistance programs have been developed. It is also necessary to improve the working conditions for female anesthesiologists to allow them to continue their work, and to provide education for young female physicians to enhance their professional pride.

Auditory evoked potential index does not correlate with observer assessment of alertness and sedation score during 0.5% bupivacaine spinal anesthesia with nitrous oxide sedation alone.

PURPOSE: The aim of this study was to evaluate the auditory evoked potential (AEP) index as a hypnosis monitor during nitrous oxide (N(2)O) sedation added to spinal analgesia. METHODS: Forty-five patients scheduled to undergo surgery under spinal anesthesia were recruited after giving informed consent. Adequate anesthesia levels were confirmed, and a disposable AEP index sensor (aepEX, Medical Device Management) was placed. A tight facemask was fitted, and a fresh gas flow of 100% oxygen 10 L/min was provided. AEP index monitoring was then initiated, and measurements and observer assessment of alertness/sedation (OAA/S) scores were recorded manually. N(2)O was administered in stepwise increases in the end-tidal concentration of 33%, 50%, and 67%. Paired AEP index and OAA/S scores were obtained immediately before each change in N(2)O concentration. RESULTS: Sixteen patients were excluded from final analysis because of nausea, vomiting, or abnormal excitatory behaviors. The increases in N(2)O concentration induced significant decreases in OAA/S scores and no substantial AEP index changes. Although OAA/S scores of 1 and 2 were observed in only two and five patients, respectively, a reduction in the OAA/S score from 5 to 1 was associated with a significant decrease in AEP index to the level indicative of moderate sedation. CONCLUSION: The AEP index might not be a suitable indicator of light hypnosis as defined by an OAA/S score of ≥3 during sedation with N(2)O alone.

[Prolonged hoarseness and arytenoid dislocation after endotracheal intubation].

We present a case of prolonged hoarseness after tracheal intubation in a 62-year-old woman with bronchial asthma who underwent a pylorogastrectomy under a combination of epidural and general anesthesia. After the induction of anesthesia, the patient was carefully intubated using a 7.5-mm cuffed endotracheal tube without a stylet to avoid causing an asthma attack; the patient was extubated approximately 6 hours after the tracheal intubation. On the first postoperative day, the patient complained of hoarseness, vocal fatigue, and dysphagia. A direct laryngoscopy performed by an otorhinolaryngologist revealed dyskinesia of the left vocal cord and sufficient arytenoid cartilage mobility. The poor vocal fold mobility was probably caused by the force exerted on the left arytenoid by the convex curvature of the endotracheal tube, which had been inserted from the right side of the mouth, or a backward pressure on the thyroid cartilage during intubation. Early treatment is crucial in such cases, since the cricoarytenoid joint can become fibrosed in an unfavorable position. Fortunately, all the symptoms disappeared after one month in the present case. Although the trigger responsible for the spontaneous healing remains unknown, natural recovery might be associated with proper use of the vocal cords.