Multi-Modal Multi-Array Electrochemical and Optical Sensor Suite for a Biological CubeSat Payload.

CubeSats have emerged as cost-effective platforms for biological research in low Earth orbit (LEO). However, they have traditionally been limited to optical absorbance sensors for studying microbial growth. This work has made improvements to the sensing capabilities of these small satellites by incorporating electrochemical ion-selective pH and pNa sensors with optical absorbance sensors to enrich biological experimentation and greatly expand the capabilities of these payloads. We have designed, built, and tested a multi-modal multi-array electrochemical-optical sensor module and its ancillary systems, including a fluidic card and an on-board payload computer with custom firmware. Laboratory tests showed that the module could endure high flow rates (1 mL/min) without leakage, and the 27-well, 81-electrode sensor card accurately detected pH (71.0 mV/pH), sodium ion concentration (75.2 mV/pNa), and absorbance (0.067 AU), with the sensors demonstrating precise linear responses (R2 ≈ 0.99) in various test solutions. The successful development and integration of this technology conclude that CubeSat bio-payloads are now poised for more complex and detailed investigations of biological phenomena in space, marking a significant enhancement of small-satellite research capabilities.

Serratus Anterior Plane Block and Intercostal Nerve Block after Thoracoscopic Surgery.

BACKGROUND: This study aimed to compare the postoperative analgesic effect between ultrasound-guided serratus anterior plane block (Group S, SAPB) and intercostal nerve block (Group I, ICNB) after single port video-assisted thoracoscopic surgery (S-VATS) in primary spontaneous pneumothorax. METHODS: In this prospective randomized controlled study, 54 patients were randomly assigned to two groups. Patients in Group S underwent the SAPB before the surgical drape by an anesthesiologist, and in Group I, ICNBs were performed just before the wound closure after S-VATS by an attending thoracic surgeon. The primary outcome was the numeric pain rating scale (NRS) score given by the patients for pain at the surgical incision site. NRS was assessed during resting and coughing statuses at 3, 6, and 12 hours postoperatively and at the time of the chest tube removal. The secondary outcomes included the number of nonsteroidal anti-inflammatory drugs (NSAIDs) and opioid administration until time to chest tube removal. RESULTS: There were no statistical differences between the two groups regarding age, body mass index, duration of operation, duration of anesthesia, and average NRS scores for the assigned time periods. There was no statistical significance in the number of opioid injections; however, NSAIDs were administered 2.8 times per patient in Group I, and 1.9 times per patient in Group S (p = 0.038). CONCLUSION: In the patients who underwent S-VATS with primary spontaneous pneumothorax, the SAPB provided similar postoperative pain relief with reducing the NSAIDs consumption compared with ICNB.

High Frequency, 2 mm-diameter Forward-viewing 2D Array for 3D Intracoronary Blood Flow Imaging.

Coronary artery disease (CAD) is one of the leading causes of death globally. Currently, diagnosis and intervention in CAD are typically performed via minimally-invasive cardiac catheterization procedures. Using current diagnostic technology such as angiography and FFR, interventional cardiologists must decide which patients require intervention and which can be deferred. 10% of patients with stable CAD are incorrectly deferred using current diagnostic best practices. By developing a forward-viewing intravascular ultrasound (FV-IVUS) 2D array capable of simultaneously evaluating morphology, hemodynamics, and plaque composition, physicians would be better able to stratify risk of major adverse cardiac events in patients with intermediate stenosis. For this application, a forward-viewing, 16 MHz 2D array transducer was designed and fabricated. A 2 mm-diameter aperture consisting of 140 elements, with element dimensions of 98 µm × 98 µm × 70 µm (w × h × t) and a nominal inter-element spacing of 120 µm was designed for this application based on simulations. The acoustic stack for this array was developed with a designed center frequency of 16 MHz. A novel via-less interconnect was developed to enable electrical connections to fan out from a 140-element 2D array with 120 µm inter-element spacing. The fabricated array transducer had 96/140 functioning elements operating at a center frequency of 16 MHz with a -6 dB fractional bandwidth of 62 ± 7%. Single element SNR was 23 ± 3 dB, and the measured electrical crosstalk was -33 ± 3 dB. In imaging experiments, the measured lateral resolution was 0.231 mm and the measured axial resolution was 0.244 mm at a depth of 5 mm. Finally, the transducer was used to perform 3D B-mode imaging of a 3 mm-diameter spring and 3D B-mode and power Doppler imaging of a tissue-mimicking phantom.

Dynamic Coronary Blood Flow Velocity and Wall Shear Stress Estimation Using Ultrasound in an Ex Vivo Porcine Heart.

PURPOSE: Wall shear stress (WSS) is a critically important physical factor contributing to atherosclerosis. Mapping the spatial distribution of local, oscillatory WSS can identify important mechanisms underlying the progression of coronary artery disease. METHODS: In this study, blood flow velocity and time-varying WSS were estimated in the left anterior descending (LAD) coronary artery of an ex vivo beating porcine heart using ultrasound with an 18 MHz linear array transducer aligned with the LAD in a forward-viewing orientation. A pulsatile heart loop with physiologically-accurate flow was created using a pulsatile pump. The coronary artery wall motion was compensated using a local block matching technique. Next, 2D and 3D velocity magnitude and WSS maps in the LAD coronary artery were estimated at different time points in the cardiac cycle using an ultrafast Doppler approach. The blood flow velocity estimated using the presented approach was compared with a commercially-available, calibrated single element blood flow velocity measurement system. RESULTS: The resulting root mean square error (RMSE) of 2D velocity magnitude acquired from a high frequency, linear array transducer was less than 8% of the maximum velocity estimated by the commercial system. CONCLUSION: When implemented in a forward-viewing intravascular ultrasound device, the presented approach will enable dynamic estimation of WSS, an indicator of plaque vulnerability in coronary arteries.

Deficiency of circadian clock gene Bmal1 exacerbates noncanonical inflammasome-mediated pyroptosis and lethality via Rev-erbα-C/EBPß-SAA1 axis.

Circadian arrhythmia has been linked to increased susceptibility to multiple inflammatory diseases, such as sepsis. However, it remains unclear how disruption of the circadian clock modulates molecular aspects of innate immune responses, including inflammasome signaling. Here, we examined the potential role of the circadian clock in inflammasome-mediated responses through myeloid-specific deletion of BMAL1, a master circadian clock regulator. Intriguingly, Bmal1 deficiency significantly enhanced pyroptosis of macrophages and lethality of mice under noncanonical inflammasome-activating conditions but did not alter canonical inflammasome responses. Transcriptome analysis of enriched peritoneal myeloid cells revealed that Bmal1 deficiency led to a marked reduction in Rev-erbα expression at steady state and a significant increase in serum amyloid A1 (SAA1) expression upon poly(I:C) stimulation. Notably, we found that the circadian regulator Rev-erbα is critical for poly(I:C)- or interferon (IFN)-ß-induced SAA1 production, resulting in the circadian oscillation pattern of SAA1 expression in myeloid cells. Furthermore, exogenously applied SAA1 markedly increased noncanonical inflammasome-mediated pyroptosis of macrophages and lethality of mice. Intriguingly, our results revealed that type 1 IFN receptor signaling is needed for poly(I:C)- or IFN-ß-induced SAA1 production. Downstream of the type 1 IFN receptor, Rev-erbα inhibited the IFN-ß-induced association of C/EBPß with the promoter region of Saa1, leading to the reduced transcription of Saa1 in macrophages. Bmal1-deficient macrophages exhibited enhanced binding of C/EBPß to Saa1. Consistently, the blockade of Rev-erbα by SR8278 significantly increased poly(I:C)-stimulated SAA1 transcription and noncanonical inflammasome-mediated lethality in mice. Collectively, our data demonstrate a potent suppressive effect of the circadian clock BMAL1 on the noncanonical inflammasome response via the Rev-erbα-C/EBPß-SAA1 axis.

Effects of propofol-remifentanil versus sevoflurane-remifentanil on acute postoperative pain after total shoulder arthroplasty: a randomized trial.

BACKGROUND: While some evidence indicates that propofol-based anesthesia has less postoperative pain than sevoflurane-based anesthesia, these results are controversial. We compared acute postoperative pain intensity and opioid consumption after total shoulder arthroplasty between propofol-remifentanil (PR) and sevoflurane-remifentanil (SR) anesthesia. METHODS: Among 48 patients undergoing shoulder arthroscopic surgery anesthetized with PR or SR, postoperative pain intensity was assessed at 30 minutes and at 2, 6, 12, and 24 hours. The total patient-controlled analgesia volume and number of patients requiring rescue analgesics were assessed. RESULTS: No significant difference in postoperative pain intensity was observed between the two groups. Postoperative opioid consumption and analgesic requirements were also comparable in the first 24 hours after surgery. CONCLUSION: PR and SR anesthesia for shoulder arthroscopic surgery provide comparable postoperative analgesia results.

Sugammadex-induced bronchospasm: a case report.

Sugammadex has shown faster reversal of steroidal neuromuscular blockade (NMB) than neostigmine, a traditional reversal agent for NMB, even in the intense block phase. This efficiency is possible because of the unique mechanism of action by encapsulating the NMB molecules. Therefore, with the use of sugammadex, we can also expect to avoid direct interactions with the cholinergic system and its subsequent side effects, which are disadvantages of traditional drugs. However, despite these benefits and US Food and Drug Administration (FDA) approval in 2015, rare adverse events associated with sugammadex have been reported. Herein, we report a case of bronchospasm that developed immediately after sugammadex administration.

Intra-abdominal hypertension during hip arthroscopy: a case report.

Symptomatic extravasation of irrigation fluid is a rare complication of hip arthroscopy. However, depending on the amount of fluid, intra-abdominal hypertension (IAH) may occur and even develop into abdominal compartment syndrome, which can seriously alter hemodynamic circulation. Therefore, it is important for anesthesiologists to promptly recognize the abnormal signs of IAH for early diagnosis and better clinical outcomes. Nevertheless, these signs are difficult to detect because they are usually obscured when the patient is under anesthesia and masked by surgical drapes. We report a case of IAH under general anesthesia during hip arthroscopy to highlight possible symptoms and signs.

The effect of transcutaneous electrical nerve stimulation on pain during venous cannulation.

BACKGROUND: The venous cannulation procedure was widely used in many clinical procedures; however, it is associated with pain or discomfort. OBJECTIVES: The purpose of this study was to investigate whether transcutaneous electrical nerve stimulation (TENS) could reduce pain during cannulation of vein. METHODS: One hundred patients were allocated randomly to 2 groups. In the active TENS group, TENS was delivered via 2 electrodes on the venous cannulation site (radial side of the wrist of dominant forearm) 20 minutes before venous cannulation, and the control group received placebo (no current) TENS. Venous cannulation with a 22-gauge cannula was performed. During venous cannulation, the pain intensity (0 = no pain, 10 = worst pain imaginable) was measured. Any side effects during study periods were recorded. RESULTS: The incidence of pain during venous cannulation was similar between the 2 groups. However, pain intensity was significantly lower in the active TENS group than placebo group (P < 0.01). There was no significant difference in the side effects such as erythema and itching between the groups. CONCLUSIONS: TENS may be a suitable option for reducing the pain intensity during venous cannulation. ClinicalTrials.gov identifier: NCT01607463.

Management of symptomatic cervical facet cyst with cervical interlaminar epidural block: A case report.

BACKGROUND: Symptomatic cervical facet cysts are relatively rare compared to those in the lumbar region. These cysts are usually located in the 7th cervical and 1st thoracic vertebral (C7/T1) area, and surgical excision is performed in most cases. However, facet cysts are associated with degenerative conditions, and elderly patients are often ineligible for surgical procedures. Cervical interlaminar epidural block has been used in patients with cervical radiating symptoms and achieved good results. Therefore, cervical interlaminar epidural block may be the first-choice treatment for symptomatic cervical facet cysts. CASE SUMMARY: A 70-year-old man complained of a tingling sensation in the left hand, focused on the 4th and 5th fingers, for 1 year, and posterior neck pain for over 5 mo. The patient's numeric rating scale (NRS) score was 5/10. The patient was diagnosed with symptomatic cervical facet cyst at the left C7/T1 facet joint. Fluoroscopy-guided cervical interlaminar epidural block at the C7/T1 level with 20 mg triamcinolone and 5 mL of 0.5% lidocaine was administered. The patient's symptoms improved immediately after the block, with an NRS score of 3 points. After 3 mo, his left posterior neck pain and tingling along the left 8th cervical dermatome were relieved, with an NRS score of 2. CONCLUSION: A cervical interlaminar epidural block is a good alternative for managing symptomatic cervical facet cysts.

A performance improvement of enzyme-based electrochemical lactate sensor fabricated by electroplating novel PdCu mediator on a laser induced graphene electrode.

A lactate sensor for lactate sensing using porous laser-induced graphene (LIG) electrodes with an electrodeposited PdCu catalyst was developed in this study. CO2 laser was used to convert the polyimide film surface to multilayered LIG. The morphology and composition of LIG were analyzed through field-emission scanning electron microscopy and Raman spectroscopy, respectively, to confirm that the fabricated LIG electrode was composed of porous and stacked graphene layers. PdCu was electrodeposited on the LIG electrode and lactate oxidase (LOx) was immobilized on the LIG surface to create a LOx/PdCu/LIG structure. According to the Randles-Sevcík equation, the calculated active surface area of the fabricated PdCu/LIG electrode was ∼12.8 mm2, which was larger than the apparent area of PdCu/LIG (1.766 mm2) by a factor of 7.25. The measured sensitivities of the fabricated lactate sensors with the LOx/PdCu/LIG electrode were -51.91 µA/mM·cm2 (0.1-5 mM) and -17.18 µA/mM·cm2 (5-30 mM). The calculated limit of detection was 0.28 µM. The selectivity of the fabricated lactate sensor is excellent toward various potentially interfering materials such as ascorbic acid, uric acid, lactose, sucrose, K+ and Na+.

Accidental esophageal intubation via a large type C congenital tracheoesophageal fistula: A case report.

BACKGROUND: Tracheoesophageal fistula (TEF) is a congenital anomaly characterized by interruptions in esophageal continuity with or without fistulous communication to the trachea. Anesthetic management during TEF repair is challenging because of the difficulty of perioperative airway management. It is important to determine the appropriate position of the endotracheal tube (ETT) for proper ventilation and to prevent excessive gastric dilatation. Therefore, the tip of the ETT should be placed immediately below the fistula and above the carina. CASE SUMMARY: A full-term, one-day-old, 2.4 kg, 50 cm male neonate was diagnosed with TEF type C. During induction, an ETT was inserted using video laryngoscope and advanced deeply to ensure that the tip passed over the fistula, according to known strategies. The passage of the ETT through the vocal cords was confirmed via video laryngoscope. However, after inflating the ETT cuff, breath sounds were not heard on bilateral lung auscultation. Instead, gastric sounds were heard. Considering that a large fistula (approximately 6.60 mm × 4.54 mm) located 10.2 mm above the carina was confirmed on preoperative tracheal computed tomography, the possibility of unintentional esophageal intubation was highly suspected. Therefore, we decided to uncuff and withdraw the ETT carefully for repositioning, while monitoring auscultation and end-tidal CO2 simultaneously. At a certain point (9.5 cm from the lip), clear breath sounds and proper end-tidal CO2 readings were suddenly achieved, and adequate ventilation was possible. CONCLUSION: Preanesthetic anatomical evaluation with imaging studies in TEF is necessary to minimize complications related to airway management.

Surgical Catheterization for Continuous Serratus Anterior Plane Block after Thoracoscopic Lobectomy: A Report of 3 Cases.

Serratus anterior plane block (SAPB) has been used for perioperative pain control during video-assisted thoracoscopic surgery (VATS), and the effects of continuous SAPB have been studied. This procedure is usually performed by the anesthesiologist; however, it could be performed more simply and safely by the thoracic surgeon through the use of meticulous finger dissection to create a space in the deep serratus anterior plane during surgery. We describe 3 cases of surgical catheterization for continuous SAPB in patients with lung cancer during VATS lobectomy, in which postoperative pain was effectively reduced.

Forward-viewing estimation of 3D blood flow velocity fields by intravascular ultrasound: Influence of the catheter on velocity estimation in stenoses.

Coronary artery disease is the most common type of cardiovascular disease, affecting > 18 million adults, and is responsible for > 365 k deaths per year in the U.S. alone. Wall shear stress (WSS) is an emerging indicator of likelihood of plaque rupture in coronary artery disease, however, non-invasive estimation of 3-D blood flow velocity and WSS is challenging due to the requirement for high spatial resolution at deep penetration depths in the presence of significant cardiac motion. Thus we propose minimally-invasive imaging with a catheter-based, 3-D intravascular forward-viewing ultrasound (FV US) transducer and present experiments to quantify the effect of the catheter on flow disturbance in stenotic vessel phantoms with realistic velocities and luminal diameters for both peripheral (6.33 mm) and coronary (4.74 mm) arteries. An external linear array ultrasound transducer was used to quantify 2-D velocity fields in vessel phantoms under various conditions of catheter geometry, luminal diameter, and position of the catheter relative to the stenosis at a frame rate of 5000 frames per second via a particle imaging velocimetry (PIV) approach. While a solid catheter introduced an underestimation of velocity measurement by > 20% relative to the case without a catheter, the hollow catheter introduced < 10% velocity overestimation, indicating that a hollow catheter design allowing internal blood flow reduces hemodynamic disturbance. In addition, for both peripheral and coronary arteries, the hollow catheter introduced < 3% deviation in flow velocity at the minimum luminal area compared to the control case. Finally, an initial comparison was made between velocity measurements acquired using a low frequency, catheter-based, 3-D intravascular FV US transducer and external linear array measurements, with relative error < 12% throughout the region of interest for a flow rate of 150 mL/min. While further system development is required, results suggest intravascular ultrasound characterization of blood flow velocity fields in stenotic vessels could be feasible with appropriate catheter design.

Correlation Between Intravascular Injection Rate, Pain Intensity, and Degree of Cervical Neural Foraminal Stenosis During a Cervical Transforaminal Epidural Block.

PURPOSE: Cervical transforaminal epidural blocks (CTEBs) are useful for the treatment of cervical radicular pain. However, during CTEBs, inadvertent intravascular injection can introduce particulate steroids into the bloodstream, thus leading to serious complications. Moreover, the risk factors associated with intravascular injection during CTEBs have not been identified. Cervical neural foraminal stenosis (CNFS) is a form of neural foraminal narrowing and a common cause of cervical radicular pain. In this study, we aimed to identify whether there is a correlation between the incidence of intravascular injection during CTEB, pain intensity, and the degree of CNFS. PATIENTS AND METHODS: A total of 126 patients were recruited. The patients were classified into two subgroups (group M and group S) based on the routine cervical T2-weighted axial magnetic resonance imaging (MRI) findings. Group M (n = 63) consisted of moderate CNFS patients, while group S (n = 63) consisted of severe CNFS patients. The occurrence of intravascular injection during CTEB was established using real-time fluoroscopy. The intravascular injection was determined by the spreading of the contrast medium through the vascular channel during the injection. Additionally, pain intensity was scored using a Numeric Rating Scale (NRS) before the procedure and 1 month after the procedure. RESULTS: There was no significant difference in the incidence of intravascular injection during CTEB between group M and group S (41.3% vs 39.7%, respectively; p = 0.99) and in the NRS scores before and 1 month after CTEB. However, both groups showed a significant decrease in the NRS scores at 1 month after the procedure compared with that before the procedure. CONCLUSION: The degree of CNFS does not affect the incidence of intravascular injection during CTEB. Regardless of whether patients have moderate or severe CNFS, caution should be exercised during CTEB procedures.

Serratus anterior plane block versus intercostal nerve block for postoperative analgesic effect after video-assisted thoracoscopic lobectomy: A randomized prospective study.

BACKGROUND: Serratus anterior plane block (SAPB) and intercostal nerve block (ICNB) are attractive options for multimodal analgesia in patients undergoing thoracoscopic surgery, but which block is superior remains unclear. OBJECTIVE: The present study aimed to assess the effect of SAPB versus ICNB on reducing postoperative pain after video-assisted thoracoscopic surgery (VATS) for lobectomy. METHODS: This prospective, randomized, active-intervention-controlled, subject-assessor-blinded, single-center, parallel-group trial allocated 18- to 80-year-old patients with American Society of Anesthesiologists status I to III to receive either SAPB or ICNB in a 1:1 ratio. The primary outcome was numerical pain rating scale (NRS) scores during the first 24 hours postoperatively. The secondary outcomes were postoperative cumulative doses of ketorolac and fentanyl, and the occurrence of postoperative adverse effects. RESULTS: Among the 57 patients assessed for eligibility, 50 were randomly assigned in a 1:1 ratio. Due to conversion to open thoracotomy and patient-controlled analgesia pump failure, 4 patients were excluded and 46 were analyzed. The intergroup differences in NRS scores were not statistically significant at any time point. Cumulative consumptions of fentanyl and ketorolac were also not significantly different. No perioperative adverse events occurred. Postoperative complications were also absent, except for nausea (2/23 patients [8.7% in both groups]). CONCLUSION: Results of the present study do not clarify whether SAPB or ICNB has a superior effect on reducing pain after VATS, thereby suggesting they may exert similar analgesic effects.

Comparison of Whitacre needle and Chiba needle on the incidence of intravascular injection during caudal epidural injections: A single-blind, randomized clinical consort study.

ABSTRACT: Caudal epidural injection (CEI) is effective for lumbar spinal pain. However, accidental intravascular injection reduces therapeutic efficacy of CEI and leads to fatal complications such as hematoma, and neurologic deficit. Whitacre needle has been reported to be effective for reducing intravascular injection during transforaminal epidural injection, compared with Quincke needle. The bevel of Chiba needle is shorter than that of Quincke needle. In this study we compared Whitacre needle and Chiba needle on incidence of intravascular injection during CEI.This was a single-blind, randomized clinical consort study. After institutional Review Board approval, a total of 164 patients underwent CEI were randomly allocated to one of 2 group (Whitacre needle or Chiba needle group). Intravascular injection was assessed with real-time fluoroscopy. In addition, total procedure time was measured. Data were compared between groups, and P < .05 was consideredstatistically significant.There were no differences between groups in terms of patient demographic and clinical characteristics. There was no significant difference on incidence of intravascular injection between Whitacre and Chiba needle group (11% vs 19.5%, P = .192). However, the procedure time is significantly longer in the Whitacre than Chiba needle group (172.8 ±â€Š53.8 sec vs 147.1 ±â€Š61.1 sec, P = .005).Based on current study, our results indicated that Whitacre needle was not effective to decrease the incidence of intravascular injection during CEI, compared to Chiba needle.

Comparison of the intraoperative analgesic efficacy between ultrasound-guided deep and superficial serratus anterior plane block during video-assisted thoracoscopic lobectomy: A prospective randomized clinical trial.

BACKGROUND: The serratus anterior plane block (SAPB) is a novel method that provides lateral chest wall analgesia. There are 2 methods of SAPB; deep and superficial SAPB. Each of these methods has been demonstrated to provide effective perioperative analgesia in thoracic surgery. The aim of this study was to compare the intraoperative hemodynamic and analgesic benefits of deep versus superficial SAPB during video-assisted thoracic surgery (VATS) lobectomy. METHODS: We performed a prospective, randomized, patient/assessor-blinded trial. We included patients who were 20 to 75 years of age and scheduled to undergo VATS lobectomy with American Society of Anesthesiologists physical status 1 or 2. Patients were randomly allocated to receive either ultrasound-guided deep SAPB (Group D) or superficial SAPB (Group S). The primary outcome was intraoperative remifentanil consumption. We also recorded intraoperative systolic blood pressure (SBP), heart rate (HR), emergence time, and doses of rescue drugs used to manage hemodynamic instability. RESULTS: Data for 50 patients undergoing 3-port VATS lobectomy were analyzed. Intraoperative remifentanil consumption did not differ significantly between Group D (n = 25, 715.62 ±â€Š320.36 µg) and group S (n = 25, 721.08 ±â€Š294.48 µg) (P = .97). Additionally, there were no significant differences between the 2 groups in SBP and HR at any time point, emergence time, or amount of rescue drugs used. CONCLUSION: Our study suggests that the intraoperative analgesic efficacy is similar for deep and superficial SAPB during VATS lobectomy.

3-D Intravascular Characterization of Blood Flow Velocity Fields with a Forward-Viewing 2-D Array.

Risk stratification in coronary artery disease is an ongoing challenge for which few tools are available for quantifying physiology within coronary arteries. Recently, anatomy-driven computational fluid dynamic modeling has enabled the mapping of local flow dynamics in coronary stenoses, with derived parameters such as WSS exhibiting a strong capability for predicting adverse clinical events on a patient-specific basis. As cardiac catheterization is common in patients with coronary artery disease, minimally invasive technologies capable of identifying pathologic flow in situ in real time could have a significant impact on clinical decision- making. As a step toward in vivo quantification of slow flow near the arterial wall, proof-of-concept for 3-D intravascular imaging of blood flow dynamics is provided using a 118-element forward-viewing ring array transducer and a research ultrasound system. Blood flow velocity components are estimated in the direction of primary flow using an unfocused wave Doppler approach, and in the lateral and elevation directions, using a transverse oscillation approach. This intravascular 3-D vector velocity system is illustrated by acquiring real-time 3-D data sets in phantom experiments and in vivo in the femoral artery of a pig. The effect of the catheter on blood flow dynamics is also experimentally assessed in flow phantoms with both straight and stenotic vessels. Results indicate that 3-D flow dynamics can be measured using a small form factor device and that a hollow catheter design may provide minimal disturbance to flow measurements in a stenosis (peak velocity: 54.97 ± 2.13 cm/s without catheter vs. 51.37 ± 1.08 cm/s with hollow catheter, 6.5% error). In the future, such technologies could enable estimation of 3-D flow dynamics near the wall in patients already undergoing catheterization.

Effects of Blood Transfusion on Hepatic Ischemia-Reperfusion Injury-Induced Renal Tubular Injury.

OBJECTIVES: Hepatic ischemia-reperfusion injury and transfusion of red blood cells in liver surgery are wellknown risk factors to induce acute tubular injury. Transfusion of stored red blood cells may affect hepatic ischemia-reperfusion injury-induced acute tubular injury. Here, we hypothesized whether preischemic (due to increased severity of hepatic injury) and postischemic (due to renal uptake of free heme and iron) transfusion of stored red blood cells may potentiate acute tubular injury in rats subjected to hepatic ischemia-reperfusion injury. MATERIALS AND METHODS: Sprague Dawley rats (n = 24) were divided into 4 groups: sham operation (sham group), hepatic ischemia-reperfusion injury only (injury-only group), red blood cell transfusion before hepatic ischemia-reperfusion injury (preinjury transfusion group), and red blood celltransfusion after hepatic ischemia-reperfusion injury (postinjury transfusion group). Partial hepatic ischemia was induced for 90 minutes, with reperfusion allowed for 12 hours. Hepatic and renal tubular injury markers, renal mRNA levels of oxidant stress markers, and inflammatory markers were assessed. Renal cortex samples were examined under hematoxylin and eosin staining for tubular histopathologic score and immunohistochemical staining forinflammatory cells. RESULTS: With regard to hepatic and renal tubular injury markers, serum alanine aminotransferase, serum urea nitrogen, and histopathologic scores were increased in the preinjury and postinjury transfusion groups versus injury-only group, with moderate to strong correlation between alanine aminotransferase and tubular injury markers. Renal oxidative stress markers (heme oxygenase-1 and neutrophil gelatinaseassociated lipocalin) were correlated with increased alanine aminotransferase, with upregulation of oxidant stress markers in the preinjury transfusion group versus sham group (all markers), as well as in the injury-only and postinjury transfusion groups (heme oxygenase-1 only). We observed no changes in renal inflammatory responses among the groups. CONCLUSIONS: Preischemic transfusion potentiated acute tubular injury without triggering renal inflammatory responses. Exacerbation of hepatic injury may induce acute tubular injury via renal oxidant stress.