Pleth variability index can predict spinal anaesthesia-induced hypotension in patients undergoing caesarean delivery.

BACKGROUND: Spinal anaesthesia carries a risk of hypotension. We hypothesized that pleth variability index and perfusion index would assess maternal volume status, and thus, allow identification of patients at higher risk of developing hypotension after spinal anaesthesia for caesarean delivery. METHODS: Fifty patients undergoing elective caesarean delivery were enrolled. All patients received spinal anaesthesia with 0.5% hyperbaric bupivacaine (10 mg) and fentanyl (10 mcg). Blood pressure was measured every minute. Pleth variability index and perfusion index were automatically measured throughout the procedure using pulse oximetry on the index finger. In case of hypotension (systolic blood pressure below 90 mmHg or 80% of the baseline value), ephedrine 5 mg was administered. Receiver-operating characteristic and multivariate logistic regression analyses for spinal anaesthesia-induced hypotension were performed. RESULTS: Hypotension occurred in 32 patients (64%). The areas under the receiver-operating characteristic curve were 0.751 (95% confidence interval: 0.597-0.904) for pleth variability index before anaesthesia, 0.793 (95% confidence interval: 0.655-0.930) for pleth variability index after anaesthesia and 0.731 (95% confidence interval: 0.570-0.892) for perfusion index change (percent change in perfusion index induced by spinal anaesthesia). The optimal threshold value of pleth variability index (after anaesthesia) for predicting hypotension was 18% (sensitivity: 78.1%, specificity: 83.3%). Pleth variability index after spinal anaesthesia was an independent factor for hypotension (odds ratio: 1.21, P = 0.041). CONCLUSIONS: Pleth variability index after spinal anaesthesia was a good predictor of spinal anaesthesia-induced hypotension in patients undergoing caesarean delivery. In addition, perfusion index change after spinal anaesthesia has the potential to predict hypotension.

Accuracy and precision of non-invasive cardiac output monitoring devices in perioperative medicine: a systematic review and meta-analysis†.

Cardiac output (CO) measurement is crucial for the guidance of therapeutic decisions in critically ill and high-risk surgical patients. Newly developed completely non-invasive CO technologies are commercially available; however, their accuracy and precision have not recently been evaluated in a meta-analysis. We conducted a systematic search using PubMed, Cochrane Library of Clinical Trials, Scopus, and Web of Science to review published data comparing CO measured by bolus thermodilution with commercially available non-invasive technologies including pulse wave transit time, non-invasive pulse contour analysis, thoracic electrical bioimpedance/bioreactance, and CO2 rebreathing. The non-invasive CO technology was considered acceptable if the pooled estimate of percentage error was <30%, as previously recommended. Using a random-effects model, sd, pooled mean bias, and mean percentage error were calculated. An I2 statistic was also used to evaluate the inter-study heterogeneity. A total of 37 studies (1543 patients) were included. Mean CO of both methods was 4.78 litres min−1. Bias was presented as the reference method minus the tested methods in 15 studies. Only six studies assessed the random error (repeatability) of the tested device. The overall random-effects pooled bias (limits of agreement) and the percentage error were −0,13 [−2.38 , 2.12] litres min−1 and 47%, respectively. Inter-study sensitivity heterogeneity was high (I2=83%, P<0.001). With a wide percentage error, completely non-invasive CO devices are not interchangeable with bolus thermodilution. Additional studies are warranted to demonstrate their role in improving the quality of care.

Goal-Directed fluid therapy with closed-loop assistance during moderate risk surgery using noninvasive cardiac output monitoring: A pilot study.

BACKGROUND: Goal directed fluid therapy (GDFT) has been shown to improve outcomes in moderate to high-risk surgery. However, most of the present GDFT protocols based on cardiac output optimization use invasive devices and the protocols may require significant practitioner attention and intervention to apply them accurately. The aim of this prospective pilot study was to evaluate the clinical feasibility of GDFT using a closed-loop fluid administration system with a non-invasive cardiac output monitoring device (Nexfin™, BMEYE, Amsterdam, Netherlands). METHODS: Patients scheduled for elective moderate risk surgery under general anaesthesia were enrolled. The primary anaesthesia team managing the case selected GDFT targets using the controller interface and all patients received a baseline 3 ml kg(-1) h(-1) crystalloid infusion. Colloid solutions were delivered by the closed-loop system for intravascular volume expansion using data from the Nexfin™ monitor. Compliance with GDFT management was defined as acceptable when a patient spent more than 85% of the surgery time in a preload independent state (defined as pulse pressure variation <13%) or when average cardiac index during surgery was >2.5 litre min(-1) m(-2). RESULTS: A total of 13 patients were included in the study group. All patients met the established criteria for delivery of GDFT for greater than 85% of case time. The median length of stay in the hospital was 5 [3-6] days. CONCLUSION: In this pilot study, GDFT management using the closed-loop fluid administration system with a non-invasive CO monitoring device was feasible and maintained a high rate of protocol compliance. CLINICAL TRIAL REGISTRATION: NCT02020863.

The utility of intra-operative three-dimensional transoesophageal echocardiography for dynamic measurement of stroke volume.

Measurement of left ventricular stroke volume and cardiac output is very important for managing haemodynamically unstable or critically ill patients. The aims of this study were to compare stroke volume measured by three-dimensional transoesophageal echocardiography with stroke volume measured using a pulmonary artery catheter, and to examine the ability of three-dimensional transoesophageal echocardiography to track stroke volume changes induced by haemodynamic interventions. This study included 40 cardiac surgery patients. Haemodynamic variables were measured before and 2 min after haemodynamic interventions, which consisted of phenylephrine 100 µg or ephedrine 5 mg. We used Bland-Altman analysis to assess the agreement between the stroke volume measured by three-dimensional transoesophageal echocardiography and by the pulmonary artery catheter. Polar-plot and 4-quadrant plot analyses were used to assess the trending ability of three-dimensional transoesophageal echocardiography compared with the pulmonary artery catheter. Bias and percentage error were -1.2 ml and 20%, respectively. The concordance rate in the 4-quadrant analysis after phenylephrine and ephedrine administration was 75% and 84%, respectively. In the polar-plot analysis, the angular concordance rate was 66% and 73% after phenylephrine and ephedrine administration, respectively. Three-dimensional transoesophageal echocardiography was clinically acceptable for measuring stroke volume; however, it was not sufficiently reliable for tracking stroke volume changes after haemodynamic interventions.

Systemic vascular resistance has an impact on the reliability of the Vigileo-FloTrac system in measuring cardiac output and tracking cardiac output changes.

BACKGROUND: The aim of this study was to examine the ability of the Vigileo-FloTrac system to measure cardiac output (CO) and track changes in CO induced by increased vasomotor tone, under different states of systemic vascular resistance (SVR). METHODS: Forty patients undergoing cardiac surgery were enrolled. Haemodynamic variables including CO measured by the Vigileo-FloTrac system (version 3.02) (APCO), CO measured by a pulmonary artery catheter (ICO), and SVR index (SVRI) were recorded before (T1) and 2 min after (T2) phenylephrine administration (100 µg). Bland and Altman analysis was used to compare ICO and APCO at T1. We used four-quadrant plots and polar plots to compare the trending abilities between ICO and APCO. Patients were divided into three groups according to the SVRI value at T1, with low (<1200 dyn cm(-5) m(2)), normal (1200-2500 dyn cm(-5) m(2)), and high (>2500 dyn cm(-5) m(2)) SVRI states. RESULTS: A total of 155 paired data were collected. The adjusted percentage error was 46.3%, 26.4%, and 61.4%, and the concordance rate between ΔICO and ΔAPCO was 67.5%, 28.8%, and 7.7% in the low, normal, and high SVRI state, respectively. The polar plot analysis showed that the mean angular bias was -22.3°, -46.0°, and -3.51°, and the radial limits of agreement were 70°, 85°, and 87°, in the low, normal, and high SVRI state, respectively. CONCLUSIONS: These results indicate that the reliability of the Vigileo-FloTrac system to measure CO and track changes in CO induced by phenylephrine administration was not clinically acceptable.

Spike-monitoring of anaesthesia for corpus callosotomy using bilateral bispectral index.

During corpus callosotomy for intractable epilepsy, the electrocorticogram is commonly recorded from electrodes placed on the brain surface to monitor of epileptic activity and assess the synchronisation of epileptic signals between the left and the right hemispheres. We evaluated the usefulness of bilateral bispectral index monitoring using two monitors and two sensors placed above the frontal region. Spikes were readily detected on the electroencephalogram on the bispectral index monitor, and the frequency of their occurrence increased or decreased in response to adjustment of the sevoflurane concentration. The disappearance of synchronisation between the left and the right hemispheres was observed with use of the bispectral index - in concordance with the electrocorticogram. Thus, 'spike-monitoring anaesthesia' using bilateral bispectral index was useful in assessing both the effect of anaesthetics on the electroencephalogram signals and the surgical therapeutic effect.

[Coronary artery bypass grafting for simultaneous subacute stent thrombosis after sirolimus-eluting stent implantation].

An 82-year-old man developed simultaneous stent thrombosis 11 days after the implantation of a sirolimus-eluting stent (SES) in the proximal left anterior descending artery (LAD) and the proximal right coronary artery (RCA). The patient immediately underwent percutaneous coronary intervention; however, his condition became critical due to the development of recurrent stent thrombosis, and emergent coronary artery bypass grafting with saphenous vein grafts was performed. Postoperative angiography showed good patency of both grafts; thrombus formation in the LAD and RCA was negative. Since the patient had a history of liver dysfunction due to ticlopidine administration, the thienopyridine derivative was not administered; this was believed to be the main cause of subacute stent thrombosis. He was administered aspirin, cilostazol, and sarpogrelate instead. A good postoperative course was achieved only using aspirin. This case demonstrates that simultaneous SES thrombosis in multivessel lesions poses a life-threatening situation.

Peculiar clinical features of cellulitis in peripheral lymphedema.

Although the occurrence of cellulitis in lymphedema (LE) is believed to be an infection-related event, many findings in its clinical course seem to suggest that it is unlikely to be an infection. Therefore, we tried to clarify the specific features of cellulitis in LE. In-hospital courses of cellulitis obtained from medical charts were reviewed in the patients with leg LE (LE; 24 patients, 72admissions), chronic venous insufficiency (CVI; 28 patients, 29 admissions), and leg cellulitis secondary to wound infection without underlying disease (N; 42 patients, 42 admissions). The patients with LE complained of less local pain (peak numerical scale; LE: 1.4 ± 1.7, CVI: 4.1 ± 2.5, N: 3.2 ±2.0, p < 0.0001), showed an abnormally higher peak procalcitonin level (LE: 33.8 ± 34.8 (N = 7), CVI: 2.9 ± 5.8 (N = 8), N: 0.4 ± 0.6(N = 10), p < 0.05), and required fewer antibiotics (LE: 1.1 ± 0.3, CVI: 1.8 ± 0.9, N: 1.5 ± 0.9, p < 0.0001). These findings suggested that the occurrence of cellulitis in LE seems unlikely to be an infection-related type of cellulitis similar to that found in CVI.

[Rupture of the descending thoracic aortic aneurysm in the lung: report of a case].

A 65-year-old man underwent a prosthetic graft replacement for a rupture of the saccular descending thoracic aneurysm in the lung. Chest computed tomography (CT) performed on the day of admission was suggestive of a thrombosed localized aortic dissection. However, sagittal plane CT performed on the following day indicated the rupture of a penetrating atherosclerotic ulcer. The operation was performed approximately 36h after the onset of the symptom since diagnosis was difficult due to the following reasons. First, the size of the saccular aortic aneurysm was not sufficiently large, i.e., it was 4.5 cm diameter and 3.0 cm in length. Second, the aneurysm was completely filled with thrombus: therefore, it could not be enhanced on CT scanning. Third, since the aneurysm was present on the side of the greater curvature of the descending aorta, the protrusion of the aneurysm was very indistinct. Fourth, the amount of bleeding was not significant because the rupture was extremely small, approximately 2 mm in width. Fifth, only an interlobar hematoma was observed due to the tight adhesion of the lung with the aorta.

[Emergent coronary artery bypass grafting in a survivor of out-of-hospital cardiac arrest].

We report a case of emergent coronary artery bypass grafting (CABG) in a survivor of an out-of-hospital cardiac arrest. A 64-year-old male driver lost consciousness and collapsed in a rice paddy field. A bystander placed him in a car and immediately started cardiopulmonary resuscitation after confirming the presence of pulselessness and apnea. Emergency medical service providers performed a defibrillation of ventricular fibrillation by using an automated external defibrillator (AED), and the patient was transferred to the critical care center in our hospital. Coronary angiography revealed a thrombus in the left main trunk (LMT), total occlusion of the left anterior descending artery (LAD) and the right coronary artery (RCA), and 90% stenosis of the left circumflex artery (Cx). Since the patient recovered consciousness 1 hour after admission and did not undergo any critical trauma, an on-pump CABG was performed for 3 vessels. He was discharged on the postoperative day 23, and he resumed a normal life.

[Giant cardiac metastasis of myxoid liposarcoma causing cardiac tamponade; report of a case].

We report a very rare case of cardiac metastasis of myxoid liposarcoma. A 55-year-old man presented with dyspnea. Two and a half years ago, he underwent resection of myxoid liposarcoma in the left thigh. Magnetic resonance imaging (MRI) revealed a giant tumor occupying the pericardiac cavity and pressing the heart and consequently causing cardiac tamponade. The patient underwent surgery through a left thoracotomy approach. The pericardiac cavity was filled with a giant tumor with a stalk from the right ventricle and 2 small nodules on the main pulmonary artery. He was relieved from the symptom: however, he had a recurrence of the tumor at the same site 5 months after the operation. He underwent surgery for the removal of the second tumor; however, he died 49 days after the operation. Although cardiac metastasis is a very rare condition, its awareness is essential for careful long-term follow-up for the early detection of a metastatic cardiac liposarcoma after the resection of the primary tumor.

Effect of three-size too large strong stocking on venous hemodynamics in normal subjects.

OBJECTIVES: To study the differences in impact on venous hemodynamics between larger size strong graduated elastic compression stockings (GECS) and appropriate size strong/moderate GECS. METHOD: In healthy legs fitted for a small (Group S; n = 8) and large (Group L; n = 8) GECS, air plethysmography was performed without GECS, with an appropriate size strong GECS (GECS1), with a three-size too large strong GECS (GECS2), and with an appropriate size moderate GECS (GECS3) in this order. RESULTS: In Group S, interface pressure with GECS2 was equal to or higher than that with GECS3. Decreased venous volume, unchanged ejection volume, and decreased residual volume were achieved by GECS, but differences in these parameters among GECS were not observed. Although insignificant, a similar tendency was found in Group L. CONCLUSIONS: A larger size strong GECS seemed to have equivalent interface pressure and impact on venous hemodynamics compared to an appropriate size moderate or strong GECS.

Study on different bandages and application techniques for achieving stiffer compression.

OBJECTIVES: The objective of this study was to investigate the relationship between interface pressure and stiffness of compression achieved by various combinations of bandages and application techniques. METHOD: There were eight healthy volunteers. One roll (4.5 m) of four types of bandages with different extensibilities (0, 90, 108 and 218%) was applied to the leg in single-layer bandage fashion with eight random tensions. Then, the leg was wrapped with one to eight rolls in multi-layer bandage fashion. RESULTS: Each combination of bandage and application technique displayed an indigenous linear interface pressure-static stiffness index relationship. With single-layer bandage, lower extensibility was associated with higher static stiffness index at a given interface pressure. With multi-layer bandage, the static stiffness index at a given interface pressure was independent of the bandage type. CONCLUSION: The stiffness at a given interface pressure was affected by the extensibility with single-layer bandage but not with multi-layer bandage.

Ligand recognition by beta 3 integrins.

Integrins are alpha/beta heterodimeric adhesion receptors, alpha IIb beta 3 (GPIIb-IIIa) and alpha v beta 3 (the vitronectin receptor) share the same beta subunit, beta 3, but have distinct alpha subunits. These sister integrins not only recognize many of the same ligands but also have certain unique ligands. Based upon current information in the literature, we propose that four classes of beta 3 ligands can be distinguished. Since the beta 3 integrins have multiple functions in vivo and are targets for therapy, this classification system may be useful in the design and characterization of therapeutic agents.

Direct coronary artery perfusion from the left ventricle.

OBJECTIVES: Trends in coronary bypass surgery require less invasive techniques and more conduits. We investigated the ability of direct coronary perfusion from the left ventricle to support regional and global cardiac function. METHODS: A conduit was established between the left ventricle and left anterior descending coronary artery (n = 6) with an interposed Starling resistor that allowed for graded regulation of backward flow. Changes of coronary flow, regional function in the territory of the left anterior descending coronary artery, and reactive hyperemia were studied. In 3 separate dogs, functional tolerance to increased heart rate was tested. In another 3 dogs, left ventricle-left anterior descending and left ventricle-left circumflex coronary artery conduits were established simultaneously (double conduit), and global function was tested. RESULTS: Without flow regulation, flow through the left ventricle-left anterior descending conduit exhibited high peaking (102 +/- 35 mL/min), midsystolic forward flow, and large pandiastolic backward flow (peaking at -47 +/- 22 mL/min). Mean coronary flow and regional function were maintained at 46.0% +/- 7.1% (35.8%-54.2%) and 45.3% +/- 29.1% (-1.8%-74.2%) of their respective normal values. When the Starling resistor was used to regulate backward flow, these values increased to 70.8% +/- 12.5% (56.8%-90.4%) and 70.2% +/- 27.8% (23.6%-107.7%), respectively. Coronary and functional reserve with a left ventricle-left anterior descending conduit were not observed. With the double conduit, global ventricular contractility indexed by end-systolic pressure-volume relation averaged 46% +/- 35% of its normal value. CONCLUSIONS: A left ventricle-coronary artery conduit supplied approximately 45% of normal blood flow and regional function, and both were improved by regulation of backward flow. Therefore, a conduit from the left ventricle to an epicardial vessel could serve as a rapidly deployable means of revascularizing totally occluded coronary vessels for which suitable natural conduits are not available.

Fibrinogen binds to integrin alpha(5)beta(1) via the carboxyl-terminal RGD site of the Aalpha-chain.

Fibrinogen interactions with vascular endothelial cells are implicated in various physiological and pathophysiological events, including angiogenesis and wound healing. We have shown previously that integrin alpha(5)beta(1) is a fibrinogen receptor on endothelial cells [Suehiro, K., Gailit, J., and Plow, E.F. (1997) J. Biol. Chem. 272, 5360-5366]. In the present study, we have characterized fibrinogen interactions with purified alpha(5)beta(1) and have identified the recognition sequence in fibrinogen for alpha(5)beta(1). The binding of fibrinogen to immobilized alpha(5)beta(1) was selectively supported by Mn(2+). Fibrinogen bound to purified alpha(5)beta(1) in a time-dependent, specific, and saturable manner in the presence of Mn(2+), and the binding was blocked completely by Arg-Gly-Asp (RGD)-containing peptides and by anti-alpha(5) and anti-alpha(5)beta(1) monoclonal antibodies. A monoclonal antibody directed to the C-terminal RGD sequence at Aalpha572-574 significantly inhibited the binding of fibrinogen to alpha(5)beta(1), whereas monoclonal antibodies directed to either the N-terminal RGD sequence at Aalpha95-97 or the C-terminus of the gamma-chain did not. Furthermore, substituting RGE for RGD at position Aalpha95-97 in recombinant fibrinogen had a minimal effect on binding, whereas substituting RGE for RGD at position Aalpha572-574 decreased binding by 90%. These results demonstrate that the C-terminal RGD sequence at Aalpha572-574 is required for the interaction of fibrinogen with alpha(5)beta(1).

Short-latency vergence eye movements elicited by looming step in monkeys.

The looming associated with forward and backward motion of the observer has been shown to elicit vergence eye movements with short-latency (approximately 80 ms) in human subjects. We studied the vergence eye movements elicited by looming in three monkeys (Macaca fuscata). The animals faced a large tangent screen onto which a random dot pattern was back-projected. The movements of both eyes were recorded with an electromagnetic induction technique. Fifty milliseconds after a centering saccade, this first pattern was replaced with a new one that showed the same image viewed from a slightly different distance. This looming step (two-frame movie) included both radial optic flow and a size change. As expected from the optical geometry, centrifugal flow coupled with enlargement (signaling forward motion) increased the vergence angle, whereas the converse combination decreased the vergence angle. In both cases, the optimal step-change in apparent viewing distance was 2%. The latency of these vergence responses was very short and similar to those induced when disparity steps are applied to such large patterns (approximately 60 ms). We suggest that these two systems act in synergy to help maintain binocular alignment during forward and backward motion of the observer.

Effects of smooth pursuit eye movement on ocular responses to sudden background motion in humans.

We studied the effects of horizontal smooth pursuit on the ocular tracking responses to brief perturbations of a textured background in humans. When the subject was fixating a stationary spot, a brief perturbation (60 degrees/s, 40 ms) of the background in any one of four directions (right, left, up, down) elicited a small tracking response. When the subject was pursuing a target moving against the stationary background, the same background perturbation elicited a larger response when in the same direction as the pursuit, but a smaller response when its direction was opposite to the pursuit; the response to vertical background perturbations was also enhanced during pursuit. When the subject was pursuing while the target and background were moving together, the same background perturbations elicited the larger responses regardless of their direction. These results indicate that the sensitivity to background motion is increased during smooth pursuit. However, when pursuit is executed against a stationary background--the usual situation in everyday life--the system is selectively insensitive to the reafferent visual input associated with pursuit, thereby reducing the potentially adverse effect of the background on pursuit performance.

Posttransplant function of a nonbeating heart is predictable by an ex vivo perfusion method.

BACKGROUND: We attempted to predict the posttransplant cardiac function of nonbeating donor hearts. METHODS: A total of 13 dogs were studied. Hearts were left in situ for 45 minutes after cardiac arrest caused by exsanguination. Hearts were then excised and reperfused in an ex vivo perfusion apparatus after 60 minutes of warm ischemia to test whether they could eject against an 80 mm Hg afterload from a preload of 10 mm Hg. Thereafter, all hearts were transplanted orthotopically. RESULTS: Four of 13 hearts were able to eject in the apparatus (group A). However, the other nine hearts could not eject under the defined conditions (group B). All four hearts in group A showed good posttransplant hemodynamics (systolic arterial pressure > 80 mm Hg with mean left atrial pressure < 10 mm Hg) without dopamine. However, none of nine hearts in group B could support the circulation without dopamine. CONCLUSIONS: Nonbeating donor heart function evaluated in the perfusion apparatus predicts posttransplant heart function. This method may be applicable for selection of transplantable hearts from nonbeating heart donors.

Blood clotting factor IX Nagoya 3: the molecular defect of zymogen activation caused by an arginine-145 to histidine substitution.

Factor IX Nagoya 3 (IX Nagoya 3) is a natural mutant of factor IX recognized in a patient with moderately severe hemophilia B. The patient had 0.60 units/ml of factor IX antigen and 2-5% of clotting activity. IX Nagoya 3 was purified from the patient's plasma by immunoaffinity chromatography with an anti-factor IX monoclonal antibody column. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the treatment of IX Nagoya 3 with factor XIa/calcium ions resulted in cleavage only at the Arg180-Val181 bond. The amino acid sequence analysis of one of the lysyl endopeptidase peptides derived from IX Nagoya 3 revealed that Arg-145 is replaced by His. This substitution impairs the cleavage between the light chain and the activation peptide by factor XIa/calcium ions.