Artery Catheter Research Articles

Radial Arterial Cannulation by Ultrasound-Guided Dynamic Needle-Tip Positioning Using the Short-Axis Out-of-Plane Approach Versus the Long-Axis In-Plane Approach: A Randomized Controlled Study.

Introduction Radial artery cannulation is a commonly performed invasive procedure for assessing a patient's hemodynamic status and collecting blood samples. Ultrasound guidance has shown benefits in improving the success rate of first-attempt cannulation. Two main approaches, short-axis out-of-plane (SAOOP) and long-axis in-plane (LAIP), are commonly used. A modified technique called dynamic needle-tip positioning (DNTP) using the short-axis out-of-plane approach has been reported to enhance arterial catheterization. This study aims to compare the first-attempt success rates of radial artery cannulation using the two techniques, DNTP versus LAIP, along with overall success rates, cannulation time, and number of attempts. Methods This prospective, randomized, controlled, clinical study was conducted after obtaining clearance from the Institute Ethics Committee of AIIMS, Raipur. Ninety-six patients between the ages of 18 and 50 years, undergoing elective surgery under general anesthesia, and required radial arterial cannulationwere randomized and equally allocated into two groups as the LAIP and DNTP approaches. The first-pass success rate, time to achieve successful cannulation, number of attempts needed, overall success rate within five minutes, and potential complications, such as thrombosis, vasospasm, and hematoma, were recorded. Results A total of 96 patients were included, with 48 in the LAIP group and 48 in the DNTP group. The DNTP group showed statistically significant advantages over the LAIP group, with a higher first-pass success rate (97.9% vs. 83.3%; p = 0.014) and shorter time to achieve successful cannulation (9.29±3.79 vs. 26.16±20.22 seconds; p = 0.001). Conclusion The ultrasound-guided short-axis DNTP technique for radial artery cannulation demonstrated a significant advantage as compared to the LAIP technique. The DNTP technique resulted in higher first-attempt cannulation success and shorter cannulation time.

Hemodynamic Monitoring In The Cardiac Surgical Patient: Comparison of Three Arterial Catheters

ObjectiveSystemic systolic (SAP) and mean (MAP) arterial pressure monitoring is the cornerstone in hemodynamic management of the cardiac surgical patient and the radial artery is the most common site of catheter placement. The present study compares three different arterial line procedures. It is hypothesized that a 20-G 12.7cm catheter inserted in the radial artery will be equal to 20-G 12.7cm angiocath placed in the brachial artery, and superior to a 20-G 5.0cm angiocath placed in the radial artery. DesignA prospective randomized control was performed. SettingSingle Academic University Hospital ParticipantsAdult patients ≥ 18 years old undergoing non-emergent cardiac surgery utilizing cardiopulmonary bypass. InterventionsAfter approval by the Rhode Island Hospital institutional review board, a randomized prospective control study to evaluate three different peripheral intra-arterial catheter systems was performed: 1) Radial Short (RS). 20-G 5cm catheter, 2) Radial Long (RL): 20-G 12cm catheter, 3) Brachial Long (BL): 20-G 12cm catheter. Measurements&ResultsGradients between central aortic and peripheral catheters (CA-P) were compared and analyzed prior to CPB, and 2 and 10 minutes after separation from CPB. The placement of femoral arterial lines, and administration of vasoactive medications were recorded. After exclusions 67 BL, 61 RL, and 66 RS patients were compared. Prior to CPB CA-P SAP and MAP gradients were not significant among the three groups. Two minutes after CPB the CA-P SAP gradient was significant for the RS group (p=0.005) and insignificant for BL (p=0.47) and RL (p=0.39). Two-group analysis reveal that CA-P SAP gradients are similar between BL and RL (p=0.84), both of which were superior to RS (p=0.02 and p=0.04 resp.). At 10 minutes after CPB, the CA-P SAP gradient for RS remained significant (p=0.004) and similar to the gradient at 2 minutes. The CA-P SAP gradients increased from 2 to 10 minutes for BL (p=0.13) and RL (p=0.06). Two minutes after CPB the CA-P MAP gradients are significant for BL(p=0.003), RL(p< 0.0001), and RS(p< 0.0001) groups. Two-group analysis reveal that the CA-P MAP gradients were lower for the BL group compared to RL (p=0.054) and RS (p< 0.05) groups. Ten minutes after CPB, the CA-P MAP gradients in the RL and RS groups remained significant (p< 0.0001) and both greater than the BL group (p=0.002). A femoral arterial line was placed more frequently in the RS group (8/66=12.1%), than RL group (3/61=4.9%), and the BL group (2/67=3.0%). Vasopressin was administered significantly more frequently in the RS group… ConclusionRegarding CA-P SAP gradients, the RL group performed equally to the BL group, both being superior to RS. Regarding CA-P MAP gradients BL was superior to RL and RS. Clinically, femoral line placement and vasopressin administration was less for the BL and RL groups when compared to the RS group. This study demonstrates the benefits of a long (12.7cm) 20 G angiocath placed in the radial artery.

Cannula Placement for Cerebral Protection Without Circulatory Arrest in Patients Undergoing Hemiarch Aortic Aneurysm Repair.

Aortic aneurysms involving the proximal aortic arch, which require hemiarch-type repair, typically require circulatory arrest with antegrade cerebral perfusion. Left carotid antegrade cerebral perfusion (LCP) via distal arch cannulation without circulatory arrest was used in this study's patient population. The goal was to assess the operative efficiency and clinical outcomes of using a distal arch cannulation technique that would not require any hypothermic circulatory arrest (HCA) time compared with more traditional brachiocephalic artery cannulation with right-sided unilateral antegrade cerebral perfusion (RCP) and HCA. A single-center retrospective review of patients with replacement of the distal ascending aorta involving the proximal arch was performed. Patients with an intramural hematoma or dissection were excluded. Between January 2015 and December 2019, 68 adult patients had undergone a hemiarch repair because of aneurysmal disease. Analysis of baseline demographics, operative data, and clinical outcomes was performed. Comparing the 68 patients: 21 patients were treated with RCP (via brachiocephalic artery graft with HCA), and 47 patients were treated with LCP (via distal aortic arch cannulation with cross-clamp between the brachiocephalic and left common carotid arteries without HCA). Baseline characteristics and outcomes were evaluated for both groups. The LCP group was younger (LCP median [IQR] age, 60 [53-65] years vs RCP median [IQR] age, 67 [59-71] years]. Sex, race, body mass index, comorbidities, and ejection fraction were similar between the groups. Cardiopulmonary bypass time (LCP, 123 minutes vs RCP, 149 minutes) and unilateral cerebral perfusion time (LCP, 17 minutes vs RCP, 22 minutes) were longer in the RCP group. Bleeding, prolonged ventilatory support, kidney failure, and length of stay were similar. In-hospital mortality was 2% in the LCP group vs 0% in the RCP group. Stroke occurred in 2 patients (4.2%) in the LCP group and in 0% of the RCP group. Mortality at 6 months in the LCP and RCP groups was 3% and 10%, respectively. Distal arch cannulation with LCP without HCA is a reasonable and safe alternative strategy for patients requiring hemiarch replacement for aneurysmal disease. This technique may provide additional benefits by avoiding circulatory arrest in these complex cases.

Percutaneous retrieval of embolized umbilical arterial catheter in extreme premature infant

Background: Umbilical arterial catheterization is a common procedure performed on critically ill neonates, especially those with extreme prematurity. Various complications have been described following umbilical artery catheter (UAC) placement including thrombosis, embolism, vasospasm, vascular perforation, hemorrhage, and infection. However, treatment of these complications is challenging due to the small size of this very fragile subset of patients. Methods: A 3-day old extremely preterm infant was referred to our institution for percutaneous removal of a fragmented and embolized umbilical arterial catheter. Results: Catheter retrieval was successful via a carotid approach utilizing techniques from percutaneous closure of PDA in preterm infants and trans-carotid access for PDA stent and aortic interventions. Conclusion: This case report describes the successful percutaneous retrieval of an embolized UAC fragment in an extremely preterm infant, the smallest documented in literature to date.

Validity and reliability of measurement of peripheral oxygen saturation during the 6-Minute Walk Test in patients with systemic sclerosis

Peripheral oxygen saturation (SpO2) using the fingers may have important limitations due to Raynaud’s phenomenon and sclerodactyly in patients with systemic sclerosis (SSc). Sensors located at more central body positions may be more accurate as these as less prone to Raynaud attacks. To determine the validity and reliability of the SpO2 measured at the finger, forehead, and earlobe during the 6-Minute Walk Test (6MWT). Eighty two patients with SSc had an arterial line placed while performing the 6MWT. Peripheral oxygen saturation was simultaneously measured by finger, forehead, and earlobe sensors and compared to the arterial oxygen saturation (SaO2) measured before and after the 6MWT. 40 patients repeated the 6MWT one week later to determine re-test reliability. We used Bland–Altman plots to display the agreement between SpO2 and SaO2. The intraclass correlation coefficient for repeated measurement of minimum SpO2 was calculated. The mean difference between SpO2 and SaO2 after the 6MWT was − 3% (SD: ± 5), 0% (SD: ± 2), and 1% (SD: ± 2) for the finger, forehead, and earlobe, respectively. The minimum SpO2 measured at the finger demonstrated the poorest re-test reliability: The ICC (95% CI) showed good agreement using the ear and forehead probe (ICCear = 0.89 [95% CI 0.80; 0.94]; ICCforehead = 0.77 [95% CI 0.60; 0.87]), while a modest reliability was found using the finger probe (ICCfinger = 0.65 95% CI [0.43; 0.80]). SpO2 should be measured using either the earlobe or forehead during the 6MWT in patients with SSc. Clinical Trials.Gov (NCT04650659).

Validation of a noninvasive cardiac output monitor in maternal cardiac disease: comparison of NICOM and transthoracic echocardiogram

The physiological changes to the cardiovascular system during pregnancy are considerable and are more pronounced in those with cardiac disease. In the general population, noninvasive hemodynamic monitoring is a valid alternative to pulmonary artery catheterization, which poses risk in the pregnant population. There is limited data on noninvasive cardiac output monitoring in pregnancy as an alternative to pulmonary artery catheterization. We sought to compare transthoracic echocardiography with a noninvasive cardiac output monitor (NICOM, Cheetah Medical) in pregnant patients with and without cardiac disease. This was a prospective, open-label validation study that compared 2-dimensional transthoracic echocardiography with NICOM estimations of cardiac output in each trimester of pregnancy and the postpartum period. Participants with and without cardiac disease with a singleton gestation were included. NICOM estimations of cardiac output were derived from thoracic bioreactance and compared with 2-dimensional transthoracic echocardiography for both precision and accuracy. A mean percentage difference of ±30% between the 2 devices was considered acceptable agreement between the 2 measurement techniques. A total of 58 subjects were enrolled; 36 did not have cardiac disease and 22 had cardiac disease. Heart rate measurements between the 2 devices were strongly correlated in both groups, whereas stroke volume and cardiac output measurements showed weak correlation. When comparing the techniques, the NICOM device overestimated cardiac output in the control group in all trimesters and the postpartum period (mean percentage differences were 50.3%, 52.7%, 48.1%, and 51.0% in the first, second, and third trimesters and the postpartum period, respectively). In the group with cardiac disease, the mean percentage differences were 31.9%, 29.7%, 19.6%, and 35.2% for the respective timepoints. The NICOM device consistently overestimated cardiac output when compared with 2-dimensional transthoracic echocardiography at all timepoints in the control group and in the first trimester and postpartum period for the cardiovascular disease group. The physiological changes of pregnancy, specifically the mean chest circumference and total body water, may alter the accuracy of the cardiac output measurement by the NICOM device as they are currently estimated. Although NICOM has been validated for use in the critical care setting, there is insufficient data to support its use in pregnancy.

Current Use and Impact of Pulmonary Artery Catheters on the Short-Term Outcomes in Patients With Cardiogenic Shock Treated With an Impella: Findings From the Japan Registry for Percutaneous Ventricular Assist Device (J-PVAD).

This study aimed to investigate the current use and impact of pulmonary artery catheters (PACs) in patients with cardiogenic shock (CS) who underwent Impella support. This was a prospective multicenter observational study between January 2020 and December 2021 that registered all patients with drug-refractory acute heart failure and in whom the placement of an Impella 2.5, CP, or 5.0 pump was attempted or successful in Japan. Cardiac ICUs in Japan. Between January 2020 and December 2021, a total of 3112 patients treated with an Impella were prospectively enrolled in the Japan registry for percutaneous ventricular assist device (J-PVAD). Among them, 2063 patients with CS were divided into two groups according to the PAC use. None. The primary endpoint was the 30-day mortality, and the secondary endpoints were hemolysis, acute kidney injury, sepsis, major bleeding unrelated to the Impella, and ventricular arrhythmias within 30 days. PACs were used in 1358 patients (65.8%) who underwent an Impella implantation. The use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) was significantly higher in the patients with PACs than in those without. Factors associated with PAC use were the prevalence of hypertension, out-of-hospital cardiac arrest, New York Heart Association classification IV, the lesser prevalence of a heart rate less than 50, and the use of any catecholamine. The primary and secondary endpoints did not significantly differ according to the PAC use. Focusing on the patients with VA-ECMO use, the 30-day mortality and hemolysis were univariately lower in the patients with PACs. The J-PVAD findings indicated that PAC use did not have a significant impact on the short-term outcomes in CS patients undergoing Impella support. Further prospective studies are required to explore the clinical implications of PAC-guided intensive treatment strategies in these patients.

Comparative analysis of antibiotic susceptibility patterns and clinical features of mucoid and non-mucoid Pseudomonas aeruginosa infections: a retrospective study.

Pseudomonas aeruginosa (PA) is a prevalent opportunistic pathogen that has close associations with both acute and chronic infections. However, there exists an insufficiency of accurate and comprehensive data pertaining to the antimicrobial susceptibility patterns and clinical characteristics of both mucoid and non-mucoid strains of PA (mPA and non-mPA, respectively). From January 1, 2021 to December 31, 2022, a thorough retrospective study was carried out to examine and compare the antibiotic susceptibility test outcomes and clinical characteristics of hospitalized patients with mPA and non-mPA infections. This study investigated a cohort of 111 patients who were diagnosed with mPA infections, as well as 792 patients diagnosed with non-mPA infections. Significant demographic disparities, including gender (p < 0.001), age (p < 0.001), length of hospital stay (p < 0.001), diabetes (p = 0.043), and hypertension (p < 0.001), are evident between the mPA and non-mPA groups. The mPA group commonly necessitates hospitalization for respiratory system diseases, whereas the non-mPA group is associated with concomitant cardiovascular and cerebrovascular diseases. The mPA group demonstrates lower utilization rates of medical devices, such as Foley catheter (p < 0.001), nasogastric tube (p < 0.001), mechanical ventilation (p < 0.001), tracheostomy (p < 0.001), arterial and venous catheterization (p < 0.001), and exhibits superior organ function status, including lower incidences of hypoalbuminemia (p < 0.001), septic shock (p < 0.001), liver dysfunction (p < 0.001), renal failure (p < 0.001), and respiratory failure (p < 0.001). The non-mPA group is more vulnerable to infection with two or more bacterial pathogens compared to the mPA group, with the non-mPA group frequently resulting in Enterobacteriaceae infections and the mPA group being associated with fungal infections. Variations in antibiotic sensitivity are noted for Amikacin (p < 0.001), Ciprofloxacin (p < 0.001), Cefepime (p = 0.003), and Levofloxacin (p < 0.001) in antibiotic susceptibility testing, with resistance patterns closely tied to specific antibiotic usage. There are significant demographic characteristics, clinical manifestations and antibiotic susceptibility between mPA and non-mPA infections. It is crucial to emphasize these characteristics due to their significant role in preventing and treating PA infections.

Linezolid brain penetration in neurointensive care patients.

Linezolid exposure in critically ill patients is associated with high inter-individual variability, potentially resulting in subtherapeutic antibiotic exposure. Linezolid exhibits good penetration into the CSF, but its penetration into cerebral interstitial fluid (ISF) is unknown. To determine linezolid penetration into CSF and cerebral ISF of neurointensive care patients. Five neurocritical care patients received 600 mg of linezolid IV twice daily for treatment of extracerebral infections. At steady state, blood and CSF samples were collected from arterial and ventricular catheters, and microdialysate was obtained from a cerebral intraparenchymal probe. The median fAUC0-24 was 57.6 (24.9-365) mg·h/L in plasma, 64.1 (43.5-306.1) mg·h/L in CSF, and 27.0 (10.7-217.6) mg·h/L in cerebral ISF. The median penetration ratio (fAUCbrain_or_CSF/fAUCplasma) was 0.5 (0.25-0.81) for cerebral ISF and 0.92 (0.79-1) for CSF. Cerebral ISF concentrations correlated well with plasma (R = 0.93, P < 0.001) and CSF levels (R = 0.93, P < 0.001).The median fAUC0-24/MIC ratio was ≥100 in plasma and CSF for MICs of ≤0.5 mg/L, and in cerebral ISF for MICs of ≤0.25 mg/L. The median fT>MIC was ≥80% of the dosing interval in CSF for MICs of ≤0.5 mg/L, and in plasma and cerebral ISF for MICs of ≤0.25 mg/L. Linezolid demonstrates a high degree of cerebral penetration, and brain concentrations correlate well with plasma and CSF levels. However, substantial variability in plasma levels, and thus cerebral concentrations, may result in subtherapeutic tissue concentrations in critically ill patients with standard dosing, necessitating therapeutic drug monitoring.

Accuracy of a zero-heat-flux thermometer in cardiac surgery, a prospective, multicentre, method comparison study

Accurate measurement of core temperature is of utmost importance during on-pump cardiac surgery, for detection of hypothermia before cardiopulmonary bypass (CPB), guidance of temperature management on CPB, active rewarming on CPB and guidance of warming therapy after CPB. Most temperature measurement methods are known to become inaccurate during rapid changes in core temperature and suffer from delayed detection of temperature changes. Zero-heat-flux temperature (ZHF) measurement from the lateral forehead may be an alternative, non-invasive method quantifying the core temperature. A prospective, observational, multicentre study was conducted in one hundred patients scheduled for on-pump coronary artery bypass grafting. Core temperatures were measured every minute by two zero-heat-flux thermometer (SpotOn™) and a bladder thermometer and a pulmonary artery catheter (PAC) in the period after induction of anesthesia until CPB. Accuracy and precision of both methods were compared against core temperature measured in the pulmonary artery using the method of Bland and Altman. A high accuracy (around 0.1 °C) and a very good precision (Limits of agreement (LoA) − 0.6; 0.4 °C) were found between zero-heat-flux thermometer and core temperature measured by PAC. Among the two ZHF thermometers the bias was negligible (− 0.003 °C) with narrow LoA of − 0.42 °C and 0.41 °C. In contrast, bias between bladder temperature and PAC temperature was large (0.51 °C) with corresponding LoA of − 0.06 °C and 1.1 °C. ZHF thermometers are in contrast to bladder temperature a reliable core temperature monitor in cardiac surgery during the period after induction of anestesia until CPB. The zero-heat-flux method can provide clinicians reliably with continuous and non-invasive measurements of core temperature in normothermic and mild hypothermic temperature ranges and therefore can be helpful to guide temperature management.

Comparison of noninvasive cardiac output and stroke volume measurements using electrical impedance tomography with invasive methods in a swine model.

Pulmonary artery catheterization (PAC) has been used as a clinical standard for cardiac output (CO) measurements on humans. On animals, however, an ultrasonic flow sensor (UFS) placed around the ascending aorta or pulmonary artery can measure CO and stroke volume (SV) more accurately. The objective of this paper is to compare CO and SV measurements using a noninvasive electrical impedance tomography (EIT) device and three invasive devices using UFS, PAC-CCO (continuous CO) and arterial pressure-based CO (APCO). Thirty-two pigs were anesthetized and mechanically ventilated. A UFS was placed around the pulmonary artery through thoracotomy in 11 of them, while the EIT, PAC-CCO and APCO devices were used on all of them. Afterload and contractility were changed pharmacologically, while preload was changed through bleeding and injection of fluid or blood. Twenty-three pigs completed the experiment. Among 23, the UFS was used on 7 pigs around the pulmonary artery. The percentage error (PE) between COUFS and COEIT was 26.1%, and the 10-min concordance was 92.5%. Between SVUFS and SVEIT, the PE was 24.8%, and the 10-min concordance was 94.2%. On analyzing the data from all 23 pigs, the PE between time-delay-adjusted COPAC-CCO and COEIT was 34.6%, and the 10-min concordance was 81.1%. Our results suggest that the performance of the EIT device in measuring dynamic changes of CO and SV on mechanically-ventilated pigs under different cardiac preload, afterload and contractility conditions is at least comparable to that of the PAC-CCO device. Clinical studies are needed to evaluate the utility of the EIT device as a noninvasive hemodynamic monitoring tool.

The 10Hz dynamic response of a fluid-filled pressure monitoring system is a novel alternative to the fast flush test and indicative of unacceptable systolic pressure overshoot.

The standard method for qualitatively evaluating the dynamic response is to see if the gain of the amplitude spectrum curve approaches 1 (input signal = output signal) over the frequency band of the blood pressure waveform. In a previous report, Watanabe reported that Gardner's natural frequency and damping coefficient, which are widely used as evaluation methods, do not reflect the dynamic response of the circuit. Therefore, new parameters for evaluating the dynamic response of pressure monitoring circuits were desired. In this study, arterial pressure catheters with length of 30, 60, 150, and 210 cm were prepared, and a blood pressure wave calibrator, two pressure monitors with analog output and a personal computer were used to analyze blood pressure monitoring circuits. All data collection and analytical processes were performed using step response analysis program. The gain at 10 Hz was close to 1 and the systolic blood pressure difference was small in the short circuits (30 cm, 60 cm), and the gain at 10 Hz was 1.3-1.5 in the 150 cm circuit and over 1.7 in the 210 cm circuit. The difference in systolic blood pressure increased in proportion to the length of the circuit. It could also be inferred that the gain at 10 Hz should be less than 1.2 to meet a clinically acceptable blood pressure difference. In conclusion, the gain at 10 Hz is sufficiently useful as an indicator to determine the correct systolic blood pressure.

Radiographic scores as a predictor of oxygenation index in very low-birthweight infants.

Very low birthweight infants (VLBWIs) often undergo chest radiographic examinations without standardization or objectivity. This study aimed to assess the association of two radiographic scores, the Brixia and radiographic assessment of lung edema (RALE), with oxygenation index (OI) in ventilated VLBWIs and to determine the optimal cutoff values to predict hypoxic respiratory severity. VLBWIs who received invasive respiratory support with arterial lines between January 2010 and October 2023 were enrolled in this study (n = 144). The correlation between the Brixia or RALE scores and OI was investigated. Receiver operating characteristic curve analysis was performed to determine the optimal cutoff points of the two radiographic scores for predicting OI values (OI ≥5, ≥10, and ≥15). The enrolled infants had a median gestational age of 27 weeks (interquartile range [IQR], 25-28 weeks) and a median birthweight of 855 g (IQR, 684-1003 g). Radiographic scoring methods correlated with the OI (Brixia score: r = 0.79, p < 0.001; RALE score: r = 0.72, p < 0.001). The optimal cutoff points for predicting OI values were as follows: Brixia score: OI ≥5, 10; OI ≥10, 13; OI ≥15, 15; RALE score: OI ≥5, 22; OI ≥10, 31; and OI ≥15, 40. Brixia and RALE scores are useful predictive markers of the oxygenation status in intubated VLBWIs with stable hemodynamics. These scores are easy to use and promising tools for clinicians to identify patients with a higher risk of hypoxic respiratory failure.

In-hospital outcomes in unhoused patients with cardiogenic shock in the United States: Insights from The National Inpatient Sample 2011-2019.

Unhoused patients face significant barriers to receiving health care in both the inpatient and outpatient settings. For unhoused patients with heart failure who are in extremis, there is a lack of data regarding in-hospital outcomes and resource utilization in the setting of cardiogenic shock (CS). Unhoused patients hospitalized with CS have increased mortality and decreased use of invasive therapies as compared to housed patients. The National Inpatient Sample (NIS) database was queried from 2011 to 2019 for relevant ICD-9 and ICD-10 codes to identify unhoused patients with an admission diagnosis of CS. Baseline characteristics and in-hospital outcomes between patients were compared. Binary logistic regression was used to adjust outcomes for prespecified and significantly different baseline characteristics (p < .05). We identified a weighted sample of 1 202 583 adult CS hospitalizations, of whom 4510 were unhoused (0.38%). There was no significant difference in the comorbidity adjusted odds of mortality between groups. Unhoused patients had lower odds of receiving mechanical circulatory support, left heart catheterization, percutaneous coronary intervention, or pulmonary artery catheterization. Unhoused patients had higher adjusted odds of infectious complications, undergoing intubation, or requiring restraints. These data suggest that, despite having fewer traditional comorbidities, unhoused patients have similar mortality and less access to more aggressive care than housed patients. Unhoused patients may experience under-diuresis, or more conservative care strategies, as evidenced by the higher intubation rate in this population. Further studies are needed to elucidate long-term outcomes and investigate systemic methods to ameliorate barriers to care in unhoused populations.

Reliability of Bioreactance and Pulse-Power Analysis in Measuring Cardiac Index During Open Abdominal Aortic Surgery

To investigate the accuracy, precision, and trending ability of noninvasive bioreactance-based Starling SV and the mini invasive pulse-power device LiDCOrapid as compared to thermodilution cardiac output (TDCO) as measured by pulmonary artery catheter when assessing cardiac index (CIx) in the setting of elective open abdominal aortic (AA) surgery. A prospective method-comparison study. Oulu University Hospital, Finland. Forty patients undergoing elective open abdominal aortic surgery. Intraoperative CI measurements were obtained simultaneously with TDCO and the study monitors, resulting in 627 measurement pairs with Starling SV and 497 with LiDCOrapid. The Bland-Altman method was used to investigate the agreement among the devices, and four-quadrant plots with error grids were used to assess trending ability. The agreement between TDCO and Starling SV was associated with a bias of 0.18 L/min/m2 (95% confidence interval [CI] = 0.13 to 0.23), wide limits of agreement (LOA = -1.12 to 1.47 L/min/m2), and a percentage error (PE) of 63.7 (95% CI = 52.4-71.0). The agreement between TDCO and LiDCOrapid was associated with a bias of -0.15 L/min/m2 (95% CI = -0.21 to -0.09), wide LOA (-1.56 to 1.37), and a PE of 68.7 (95% CI = 54.9-79.6). The trending ability of neither device was sufficient. The CI measurements achieved with Starling SV and LiDCOrapid were not interchangeable with TDCO, and the ability to track changes in CI was poor. These results do not support the use of either study device in monitoring CI during open AA surgery.

Impact of mechanical power and positive end expiratory pressure on central vs. mixed oxygen and carbon dioxide related variables in a population of female piglets.

The use of the pulmonary artery catheter has decreased overtime; central venous blood gases are generally used in place of mixed venous samples. We want to evaluate the accuracy of oxygen and carbon dioxide related parameters from a central versus a mixed venous sample, and whether this difference is influenced by mechanical ventilation. We analyzed 78 healthy female piglets ventilated with different mechanical power. There was a significant difference in oxygen-derived parameters between samples taken from the central venous and mixed venous blood (S O2 = 74.6%, ScvO2 = 83%, p < 0.0001). Conversely, CO2-related parameters were similar, with strong correlation. Ventilation with higher mechanical power and PEEP increased the difference between oxygen saturations, (Δ[ScvO2-S O2 ] = 7.22% vs. 10.0% respectively in the low and high MP groups, p = 0.020); carbon dioxide-related parameters remained unchanged (p = 0.344). The venous oxygen saturation (central or mixed) may be influenced by the effects of mechanical ventilation. Therefore, central venous data should be interpreted with more caution when using higher mechanical power. On the contrary, carbon dioxide-derived parameters are more stable and similar between the two sampling sites, independently of mechanical power or positive end expiratory pressures.

Abstract WP145: Quantifying Blood Pressure Variability Within the First Hour Following Endovascular Therapy

Background: Blood pressure variability (BPV) during the first 24 hours following endovascular therapy is associated with poor functional outcome. However, to be a viable treatment target, BPV needs to be recognized very quickly after large vessel recanalization. Hypothesis: We hypothesized that high frequency arterial line data will facilitate BPV quantification within 1 hour of large vessel recanalization, which will correlate with 24-hour BPV. Methods: This single-center retrospective cohort included acute stroke patients who underwent endovascular therapy during 2022 for large vessel occlusion. Eligible patients had an invasive radial artery catheter for continuous blood pressure monitoring during and after endovascular therapy. Systolic and diastolic blood pressure were recorded at 1Hz. For both systolic and diastolic, BPV was calculated over one hour and 24 hours following endovascular therapy using four techniques: (1) standard deviation, (2) coefficient of variation, (3) successive variation, and (4) average real variation. Correlation between the two time windows was evaluated for each BPV metric. Results: Of 198 patients who underwent EVT during the study time frame, 108 had the required arterial line data. BPV metrics calculated based on systolic blood pressure were at least moderated correlated between the 1-hour and 24-hour window. When calculated based on diastolic blood pressure, BPV metrics were strongly correlated between the 1-hour and 24-hour window ( Table ). Conclusions: With high frequency arterial line data, BPV, in particular diastolic variability can be reliably assessed within the first hour following large vessel recanalization. Given the previously observed relationship between BPV and functional outcome, future study is needed to explore the possibility of leveraging BPV as a treatment target during post-endovascular supportive care.

Feasibility study of a SiPM-fiber detector for non-invasive measurement of arterial input function for preclinical and clinical positron emission tomography

Pharmacokinetic positron emission tomography (PET) studies rely on the measurement of the arterial input function (AIF), which represents the time-activity curve of the radiotracer concentration in the blood plasma. Traditionally, obtaining the AIF requires invasive procedures, such as arterial catheterization, which can be challenging, time-consuming, and associated with potential risks. Therefore, the development of non-invasive techniques for AIF measurement is highly desirable. This study presents a detector for the non-invasive measurement of the AIF in PET studies. The detector is based on the combination of scintillation fibers and silicon photomultipliers (SiPMs) which leads to a very compact and rugged device. The feasibility of the detector was assessed through Monte Carlo simulations conducted on mouse tail and human wrist anatomies studying relevant parameters such as energy spectrum, detector efficiency and minimum detectable activity (MDA). The simulations involved the use of 18F and 68Ga isotopes, which exhibit significantly different positron ranges. In addition, several prototypes were built in order to study the different components of the detector including the scintillation fiber, the coating of the fiber, the SiPMs, and the operating configuration. Finally, the simulations were compared with experimental measurements conducted using a tube filled with both 18F and 68Ga to validate the obtained results. The MDA achieved for both anatomies (approximately 1000 kBq/mL for mice and 1 kBq/mL for humans) falls below the peak radiotracer concentrations typically found in PET studies, affirming the feasibility of conducting non-invasive AIF measurements with the fiber detector. The sensitivity for measurements with a tube filled with 18F (68Ga) was 1.2 (2.07) cps/(kBq/mL), while for simulations, it was 2.81 (6.23) cps/(kBq/mL). Further studies are needed to validate these results in pharmacokinetic PET studies.

Systematic approach to obtain axillary arterial access for pediatric heart catheterizations.

Axillary arterial access (AAA) in pediatric heart catheterizations is undervalued. We retrospectively reviewed children with congenital heart diseases (CHDs) who received trans-axillary arterial catheterizations between January 2019 and February 2023. We aimed ultrasound-guided punctures in the proximal two-thirds of axillary arteries with diameters ≥2 mm to insert 7 cm/4 Fr short introducers. We administrated intra-arterial verapamil (1.25 mg) and heparin (100 UI/kg). We infiltrated per-operatively 2% lignocaine (10 mg) for arterial spasms, long sheaths use (≥5 Fr), and ≥60 min procedures in <3 kg patients. We identified 30 patients (66.7% males) with a median age of 1.1 months (IQR, 0.3-5.4), and a median weight of 3.1 kg (IQR, 2.7-3.7). 5/30 patients had six redo interventions after a median of 3.9 months (IQR, 1.7-5.1). Overall, 27/36 procedures were interventional, including 6 aortic valvuloplasties, 6 balloon angioplasties, and 15 stenting procedures. The median arterial axillary angiographic diameter was 2.6 mm (IQR, 2.4-3). Access was right-sided in 23/36 (63.9%) procedures and obtained using 21G/2.5 cm bevel needles in 25/36 (69.4%) procedures. No hemodynamical change occurred after introducing spasmolytic drugs. The median fluoroscopy time was 26.1 min (IQR, 19.2-34.8). There were two self-resolving arterial dissections, one sub-occlusive arterial thrombosis (resolved with 6 weeks of enoxaparin), and one occlusive arterial thrombosis (resolved with alteplase thrombolysis and 6 weeks of enoxaparin). Median follow-up was 11.7 months (IQR, 8-17.5). Four patients with complex univentricular hearts died from non-procedural causes at a median of 40 days (IQR, 31-161) postoperative. Systematic approach for AAA is the key to success and unlocks the many potentials of trans-axillary pediatric cardiology interventions.

Effects of vitamin C on the pharmacokinetics and pharmacodynamics of nimodipine in rats.

In recent years, researchers have shown a growing interest in the interactions between different pharmaceutical agents. An intriguing instance lies in the possible interaction between nimodipine and vitamin C. To investigate the pharmacokinetic and pharmacodynamic effects of vitamin C on nimodipine in rats, rats were randomly divided into a nimodipine only group and a combination group (nimodipine + vitamin C). The two groups were given intragastric administration and nimodipine blood concentrations were determined using high-performance liquid chromatography-tandem mass spectrum at different time points. Blood pressure and heart rate were measured via carotid artery cannulation. Pharmacokinetic differences were observed between the nimodipine only group and the combination group at the same dose. Compared with the nimodipine only group, the combination group's main pharmacokinetic parameters of peak concentration and area under the curve increased significantly, and the difference was statistically significant (p < 0.05); furthermore, the combination group exhibited a significant reduction in average blood pressure, while no significant effects on heart rate were observed. Vitamin C did not affect the activity of CYP450 in rat liver. The pharmacokinetic characteristics and pharmacodynamics of nimodipine were changed by vitamin C administration in rats.