Peripheral Venous Pressure Research Articles

Correlation between Central Venous Pressure and Peripheral Venous Pressure in Medical Intensive Care Unit Patients

Introduction: Central venous pressure (CVP) is a hemodynamic variable commonly used in the intensive care setting to estimate right arterial pressure for evaluation and monitoring a patient's volume status. Risks such as infection, arterial puncture, hematoma, and pneumothorax associated with central venous cannulation can outweigh its benefits. This study was undertaken to determine if peripheral venous pressure (PVP) predicts CVP in medical intensive care unit (ICU) patients. Materials and Methods: This study was conducted on patients admitted to the medical ICU at AlJamhoriya Teaching Hospital in the period from January to September 2009. Sixty-six patients (aged 40–70 years) who were required a central venous line (CVL) were included prospectively in the study. CVP measured through internal jugular vein or subclavian vein by three ways CVL set insertion; and CVL placement was confirmed by chest X-ray. We used the manometers for the measurement of PVP; and 66 paired recordings of CVP and PVP were made. The correlation and Bland-Altman analysis of agreement were performed. Results: The mean (standard deviation [SD]; range) CVP was 11.3778 cmH2O (±5.6; −1.0–27.0); the mean PVP was 15.80 cmH2O (±5.9; 0.0–33.0); offset (bias) of PVP > CVP was 4.42 cmH2O with SD ± 3.62. The correlation of PVP on CVP was r = 0.8059, (r 2 = 0.65), P < 0.0001. The 95% confidence intervals for the bias were 3.5352–5.3133 cmH2O. In the Bland-Altman analysis, lower and upper limits of agreement (95% LOA) were 2.7 (4.43–−7.20) and 11.63 (4.4–7.2) cmH2O. Four out of 66 points were outside the LOA. The dashed zero lies between the LOA. Conclusion: Measurement of PVP from both antecubital area and dorsum of the hand correlated with CVP measurement with acceptable agreement. PVP measurement may be a noninvasive alternative way for estimating CVP.

Central and peripheral hemodynamic responses to orthostasis in hypertensive males with chronic venous disorders taking combined therapy with a calcium channel blocker and an angiotensin-converting enzyme inhibitor

Aim . To study the characteristics of central and peripheral hemodynamic responses to orthostasis in hypertensive (HTN) males with chronic venous disorders (CVD) taking combined therapy with a calcium channel blocker (CCB) and an angiotensinconverting enzyme (ACE) inhibitor. Material and methods . In 46 men 30-50 years old with uncontrolled HTN taking antihypertensive therapy, a comparative assessment of the dynamics of systolic blood pressure (SBP), diastolic blood pressure (DBP), peripheral venous pressure (PVP), lumen diameter and area, blood flow velocity of superficial and deep veins of the left leg in response to orthostasis. Venous hemodynamics was studied by duplex ultrasound. PVP was assessed by oscillometry on the thigh and ultrasound of the great superficial vein. A comparative dynamic analysis of these parameters was carried out in patients of two groups: 23 hypertensive patients without CVD and 23 patients with HTN and CVD. CVD was assessed using Comprehensive Energy Assistance Program (CEAP). Orthostasis was performed before and after 14 days of antihypertensive therapy with a combination of CCB and ACE inhibitors. Results . Central and peripheral hemodynamic responses to orthostasis before treatment in patients of both groups was the same — a decrease in SBP, DBP and PVP, expansion of superficial and deep veins, and a decrease in venous blood flow velocity. As a result of treatment, 43 patients achieved the first target office SBP (<140 mm Hg). Of these, there were 21 HTN patients without CVD and 22 patients with CVD. After treatment, most responses to orthostasis in both groups was similar to pre-treatment ones. However, differences were also noted — in both groups, the DBP increased; SBP decreased only in men with CVD. In patients with CVD, the posterior tibial vein (PTV) dilated and blood flow velocity decreased after treatment in response to orthostasis, while in patients without CVD, there was a narrowing of PTV and blood flow acceleration. After treatment, patients with CVD were characterized by a larger diameter and area of the lumen of superficial and deep veins than those without CVD in response to orthostasis. Conclusion . Orthostasis before antihypertensive therapy in patients both with and without CVD is characterized by an identical hemodynamic response — a decrease in SBP, DBP, PVP expansion of superficial and deep veins, and a decrease in venous blood flow velocity. After 14-day antihypertensive therapy, there were differences in hemodynamic response between the study groups. In patients with HTN and CVD, CCB and ACE inhibitors therapy leads to a redistribution of central and peripheral circulation and increases the dilatation of the veins in response to orthostasis.

Noninvasive Technique for Measuring Central Venous and Arterial Pressure Using Controlled Compression Sonography.

Objective: Devices that can noninvasively measure central and peripheral venous pressures with relative ease and in a short time were developed, but the resolution of the data that can be recorded with these devices is limited to 50 mmHg.Materials and Methods: We aimed to develop a system that could overcome this limitation. We used an innovative noninvasive controlled compression sonography device that could theoretically measure pressures higher than 200 mmHg. First, to validate the accuracy of our device, an in vitro study was conducted. Then, the values measured by our system were compared to conventionally obtained measurements of central venous, peripheral venous, and brachial artery pressures. Finally, regression analyses were used to determine the correlations between measurements obtained from different devices.Results: With our device, the measurement of venous and arterial pressures required only 3 to 15 sec. All regression analyses revealed a significant statistical correlation between measurements, although the correlation coefficient was relatively low for arterial pressure.Conclusion: For venous pressure, our system can provide measurements that could not be measured noninvasively with conventional methods. Regarding arterial pressure, although our system could measure systolic pressure, further studies are needed to confirm the clinical efficacy of our device.

Peripheral venous pressure accurately predicts central venous pressure in the adult Fontan circulation

BackgroundPatients with the Fontan circulation lack a subpulmonary ventricular pump and thus the main driver for pulmonary blood flow is a high central venous pressure. Peripheral venous pressure (PVP) measurement has been shown to be a reproducible and fairly accurate surrogate for central venous pressure (CVP), but not specifically for the adult Fontan circulation. This study aims to determine the relationship of PVP to CVP in adult Fontan patients. MethodsAll adult patients (≥18 yo) with a Fontan circulation undergoing cardiac catheterization were included. Both CVP and PVP were measured during the catheterization. The relationship between the peripheral venous and central venous pressures was assessed using simple linear regression and the Bland-Altman plot analysis for differences. ResultsThirty-eight adult Fontan patients (mean age 30.7 ± 8.5, range 18–52 years) undergoing 43 cardiac catheterizations were analyzed. The mean CVP was 17.3 +/− 4.7 mmHg. The mean PVP was 18.4 +/− 5 mmHg. CVP and PVP were highly correlated, with an R2 value of 0.83 (p < 0.001). The CVP can be estimated with PVP measurements using the formula CVP = (0.86 * PVP) + 1.3. A Bland-Altman plot for PVP and CVP demonstrated that the PVP overestimated CVP by a mean of 1.2 mmHg, with a 95% limit of agreement of −5.2 mmHg to 2.8 mmHg. ConclusionsIn adult Fontan patients, measuring PVP is a reliable, less-invasive, and accurate method of estimating the CVP during cardiac catheterization procedures. These findings may enable outpatient monitoring of Fontan hemodynamics.

Peripheral venous pressure changes during exercise are associated with adverse Fontan outcomes

ObjectiveElevated central venous pressure (CVP) plays an important role in the development of adverse Fontan outcomes. Peripheral venous pressure (PVP) has been validated as a surrogate for CVP in Fontan...

Relation of Peripheral Venous Pressure to Central Venous Pressure in Patients With Heart Failure, Heart Transplant, and Left Ventricular Assist Device

Peripheral venous pressure (PVP) monitoring is a noninvasive method to assess volume status. We investigated the correlation between PVP and central venous pressure (CVP) in heart failure (HF), heart transplant (HTx), and left ventricular assist device (LVAD) patients undergoing right heart catheterization (RHC). A prospective, cross-sectional study examining PVP in 100 patients from October 2018 to January 2020 was conducted. The analysis included patients undergoing RHC admitted for HF, post-HTx monitoring, or LVAD hemodynamic testing. Sixty percent of patients had HF, 30% were HTx patients, and 10% were LVAD patients. The mean PVP was 9.4 ± 5.3 mm Hg, and the mean CVP was 9.2 ± 5.8 mm Hg. The PVP and CVP were found to be highly correlated (r = 0.93, p < 0.00001). High correlation was also noted when broken down by HF (r = 0.93, p < 0.00001), HTx (r = 0.93, p < 0.00001), and LVAD groups (r = 0.94, p < 0.00005). In conclusion, there is a high degree of correlation between PVP and CVP in HF, HTx, and LVAD patients. PVP measurements can be used as a rapid, reliable, noninvasive estimate of volume status in these patient populations.

Venous Pulse Wave Velocity variation in response to a simulated fluid challenge in healthy subjects

PurposeThe evaluation of a mini or simulated fluid challenge is still a complex and open issue in the clinical setting and it is of paramount significance for the fluid therapy optimization. We here investigated the capacity of a new hemodynamic parameter, the venous Pulse Wave Velocity (vPWV), to detect the effect of passive leg raising (PLR). Materials and methodsIn 15 healthy volunteers (7 M, 8 F, age 26 ± 3) venous pressure pulses were elicited by pneumatic compressions of the left hand and proximally detected by ultrasound for calculation of the vPWV. We also non-invasively measured the basilic vein (BV) cross-sectional perimeter, and peripheral venous pressure (PVP). The PLR manoeuvre was performed twice to evaluate reliability of the assessment. ResultsThe PLR had an overall statistically significant effect on the entire set of variables (MANOVA, p < 0.05): vPWV increased from 2.11 ± 0.46 to 2.30 ± 0.47 m/s (p = 0.01; average increase: 10%). This effect was transient and dropped below 5% after about 3 min. A significant increase was also exhibited by BV size and PVP. In consecutive measurements vPWV showed little intra-subject variability (CoV = 8%) and good reliability (ICC = 0.87). Finally, the vPWV responses to the two PLRs exhibited good agreement (paired T-test: p = 0.96), and moderate reliability (ICC = 0.57). ConclusionThese results demonstrated that vPWV can be non-invasively, objectively and reliably measured in healthy subjects and that it is adequate to detect small pressure/volume variations, as induced by PLR-from-supine. These characteristics make it suitable for clinical applications.

Unsupervised anomaly detection in peripheral venous pressure signals with hidden Markov models

This paper proposes an automatic anomaly detection and removal algorithm for peripheral venous pressure (PVP) signals, which can be used to predict intravascular volume loss in humans. PVP signal collection is a minimally invasive procedure that can be performed by using a standard peripheral intravenous (PIV) catheter and a commercial pressure-monitoring transducer. PVP signals are highly susceptible to motion and noise artifacts such as patient movements or unintended manipulation of PIV lines. Anomalies in PVP signals can corrupt useful information and seriously affect the integrity of PVP signal analysis. We propose to detect and remove such anomalies by exploiting the properties of PVP signals. Specifically, a dynamic linear model (DLM) with a Kalman filter is used to track and predict the time-domain evolution of PVP signals. The prediction residuals of the Kalman filter are then modeled with a hidden Markov model (HMM), with the normal and anomalous status of the signal modeled by using binary states of a hidden Markov chain. The HMM parameters along with the hidden states are iteratively estimated by using an unsupervised learning algorithm with a modified Baum–Welch method. The anomaly detection algorithm is applied to clinical data from a cohort of 24 pediatric patients with hypertrophic pyloric stenosis. Experimental results demonstrate that the proposed unsupervised anomaly detection algorithm can efficiently remove anomalies in PVP signals without the need of a training phase. The algorithm can also be applied to other time series signals, such as Electrocardiography (ECG) and Photoplethysmogram (PPG) signals.

Comparison of Conventional Central Venous Pressure with Peripheral Venous Pressure and External Jugular Venous Pressure in Patients with Sepsis

Comparison of Conventional Central Venous Pressure with Peripheral Venous Pressure and External Jugular Venous Pressure in Patients with Sepsis

A new approach to complicated and noisy physiological waveforms analysis: peripheral venous pressure waveform as an example.

We introduce a recently developed nonlinear-type time-frequency analysis tool, synchrosqueezing transform (SST), to quantify complicated and noisy physiological waveform that has time-varying amplitude and frequency. We apply it to analyze a peripheral venous pressure (PVP) signal recorded during a seven hours aortic valve replacement procedure. In addition to showing the captured dynamics, we also quantify how accurately we can estimate the instantaneous heart rate from the PVP signal.

Sleep disordered breathing in adults living with a Fontan circulation and CPAP titration protocol

BackgroundFontan-type single ventricle physiology has exquisite respiratory dependence. Obstructive sleep apnoea (OSA) and continuous positive airway pressure (CPAP) are likely to have deleterious haemodynamic consequences. MethodsAsymptomatic and symptomatic Fontan-adults underwent diagnostic polysomnography; The overnight CPAP titration employed echocardiography and peripheral venous pressure (PVP) measurements to determine the upper limit of pressure prior to haemodynamic deterioration (> 20% rise in PVP or 20% fall in stroke volume). ResultsIn asymptomatic adults (n = 7), mean age was 32 ± 9 years and awake oxygen saturations were 92 ± 3%. There was no significant OSA with Apnoea Hypopnoea Index (AHI) of 0.6 ± 1.1 events/h and mild nocturnal hypoxaemia (nadir 89 ± 4%). In sleepy patients (n = 7, age 36 ± 7 years, awake saturations 84 ± 5%, NYHA Class III ± I), sleep efficiency was 81 ±10% with mild OSA on average (AHI 7.9 ± 10.1) events/h) and marked desaturation (nadir of 76 ± 6%); Most episodes were obstructive in nature. BMI correlated with AHI (n = 14, R = 0.7, p = .005). Two of 7 (29%) had moderate OSA characterised by an early fall in PVP, 3 ± 1 mmHg and a 2 ± 1 mmHg increase at event termination. CPAP was successfully applied through in-laboratory titration (stroke volume fall was the end-point determinant in both). ConclusionOur cohort of asymptomatic adults did not have significant SDB but SDB was common in sleepy patients. Fontan-adults with symptoms suggestive of SDB should be offered polysomnography and can be safely treated with CPAP employing echocardiographic titration.

The effects of the combination of angiotensin-converting enzyme inhibitor and diuretic on the lower limb venous circulation in men with hypertension and chronic venous disorders

Aim. To study the effects of angiotensin converting enzyme (ACE) inhibitor and diuretic combination on the lower limb venous circulation in men with hypertension (HTN) and chronic venous disorders (CVD).Material and methods. The study included 37 men with uncontrolled hypertension at the age of 46 (40-49) years, which were divided into two groups: 20 patients with objective signs of CVD (CEAP criteria) and 17 patients without CVD. During hospitalization, all participants received antihypertensive therapy with a combination of ACE inhibitor and diuretic. Vein Doppler ultrasound at rest was performed on the day of hospitalization and after 14 days. The diameter and the area of vein lumen, flow velocity and peripheral venous pressure (PVP) were recorded. Mann-Whitney and Wilcoxon tests were used for statistical analysis.Results. Initially, patients with CVD had higher values of PBP (by 26%), diameter and area of the vein lumen (53%) and flow velocity (by 14%) than in patients without CVD. As a result of therapy, in the group of patients with HTN and without CVD, systolic (SBP) and diastolic blood pressure (DBP) decreased to the target levels, PVP decreased by 13%, vein diameter increased by 27%, blood flow velocity decreased by 15%. Therapy in patients with CVD led to the normalization of SBP, DBP, and a decrease in PVP and flow velocity by 31% and 33%, respectively. No significant changes in the diameter and cross-sectional area of lower limb veins were noted.Conclusion. The obtained data showed that 14-day antihypertensive therapy with ACE inhibitor and diuretic in patients with HTN and CVD, unlike patients with HTN and without CVD, did not led to vein dilation, but was associated with flow velocity and PVP decrease. By therapy’s end, most of venous hemodynamic parameters, including PVP, were identical in the studied groups.

Physiology and clinical utility of the peripheral venous waveform

The peripheral venous system serves as a volume reservoir due to its high compliance and can yield information on intravascular volume status. Peripheral venous waveforms can be captured by direct transduction through a peripheral catheter, non-invasive piezoelectric transduction, or gleaned from other waveforms such as the plethysmograph. Older analysis techniques relied upon pressure waveforms such as peripheral venous pressure and central venous pressure as a means of evaluating fluid responsiveness. Newer peripheral venous waveform analysis techniques exist in both the time and frequency domains, and have been applied to various clinical scenarios including hypovolemia (i.e. hemorrhage, dehydration) and volume overload.

A self-powered insulin patch pump with a superabsorbent polymer as a biodegradable battery substitute.

Highly popular insulin patch pumps have in-built non-removable batteries. These batteries are routinely disposed of together with the used pumps as medical waste and end up in landfills. This is an environmental contamination conundrum by design. To address this issue, we proposed a self-powered patch pump that uses a biodegradable superabsorbent polymer (SAP) instead of a battery as a power source to drive the infusion. Continuous infusion rates from 6.1 μL min-1 to 49.1 μL min-1 were achieved. Together with valve throttling, basal and bolus infusion rates of ∼10 μL h-1 (1 U h-1) and 100 μL (10 U) in ∼11 min could also be implemented for glycemic control. The generated pressure at ∼0.7 psi is also adequate for infusion as it exceeded an adult's maximum peripheral venous pressure of 0.6 psi. Given the current number of patch pump users, the proposed design could prevent ∼100 000 used batteries from entering the medical waste stream and landfill daily. Most importantly, this work highlights the possibility of addressing environmental contamination without compromising on healthcare standards by using SAP as an alternative means of energy storage.

Abstract 20: Peripheral Intravenous Analysis Detects Return of Spontaneous Circulation Without Interruption of Chest Compressions in a Rat Model of Cardiopulmonary Resuscitation

Introduction: A higher chest compression fraction (CCF) or percentage of time providing chest compressions is associated with improved survival after cardiac arrest (CA). Pauses in chest compression duration during cardiopulmonary resuscitation (CPR) to palpate a pulse can reduce the CCF. Peripheral Intravenous Analysis (PIVA) is a novel method for determining cardiac and volume status using waveforms from a standard peripheral intravenous (IV) line. We hypothesize that PIVA will demonstrate the onset of return of spontaneous circulation (ROSC) without interruption of CPR. Methods: Eight Zucker Diabetic Fatty (ZDF) rats (4 lean, 4 diabetic) were intubated, ventilated, and cannulated with a 24g IV in the tail vein and a 22g IV in the femoral artery, each connected to a TruWave pressure transducer. Mechanical ventilation was discontinued to achieve CA. After 8 minutes, CPR began with mechanical ventilation, IV epinephrine, and chest compressions using 1.5 cm at 200 times per minute until mean arterial pressure (MAP) increased to 120 mmHg per arterial line. All waveforms were recorded and analyzed in LabChart. PIVA was measured using a Fourier transform of the peripheral venous waveform. Data are mean ± SD. Statistics: Unpaired student’s t-test (two-tailed), α = 05. Results: CA and ROSC were achieved in all 8 rats. Within 1 minute of CPR, there was a 70 ± 35 fold increase/decrease in PIVA during CPR that was temporally associated with ROSC. Within 8 ± 13 seconds of a reduction in PIVA, there was a rapid increase in end-tidal CO 2 . In all rats, ROSC occurred within 38 ± 9 seconds of the maximum PIVA value. Peripheral venous pressure decreased by 1.2 ± 0.9 mmHg during resuscitation and ROSC, which was not significant different at p=0.05. Conclusion: In this pilot study, PIVA detected ROSC without interrupting CPR. Use of PIVA may obviate the need pause CPR for pulse checks, and may result in a higher CCF and survival. Future studies will focus on PIVA and CPR efficacy.

Re-pericardiectomy for recurrent chronic constrictive pericarditis: left anterolateral thoracotomy is a better approach

BackgroundPericardiectomy is the final treatment for constrictive pericarditis. However, this greatest surgical approach is still very controversial. This study pursued to assess the outcomes in patients with recurrent chronic constrictive pericarditis undergoing reoperated pericardiectomy via median sternotomy versus left anterolateral thoracotomy and to explain which surgical approaches might be better for recurrent chronic constrictive pericarditis.MethodsA total of 24 patients were identified with recurrent chronic constrictive pericarditis and underwent reoperation with pericardiectomy between July 2003 and July 2015. The decision for this surgical approach was mainly dependent on the operating surgeon’s preference. Out of 20 patients, 16 patients underwent pericardiectomy via median sternotomy and 8 patients via left anterolateral thoracotomy pericardiectomy. Their data were obtained retrospectively from the case notes.ResultsBoth groups of patients were similar in age, gender between two operations, and also in peripheral venous pressure, cardiac rhythm and New York Heart Association (NYHA) class distribution. The mortality rates were similar in both groups with one death (12.5%) due to low cardiac output syndrome in the left anterolateral thoracotomy group and two deaths (12.5%) in the median sternotomy group. All the deaths were associated with cardiac complications and happened in the perioperative period. NYHA functional class status enhanced in most of the patients. Patients in both groups had a similar and significant improvement in their NYHA status that improved from 3.4 ± 0.7 to 1.8 ± 0.1 (P = 0.001) in the left anterolateral thoracotomy group and reduced from 3.3 ± 0.6 to 1.9 ± 0.4 (P = 0.001) in the median sternotomy group. There was a significantly greater rate of pulmonary infection in the thoracotomy group than in the median sternotomy group (50% versus 25%, P = 0.02). Nevertheless, there was a significantly greater occurrence of wound infections in the median sternotomy group in 3 patients versus in one patient of the left anterolateral thoracotomy group (18.8% versus 12.5%, P = 0.02).ConclusionsLeft thoracotomy incision was preferred to sternotomy in the current setting of this situation and was done safely without CPB. It avoided life-threatening sternal infection and it also has showed an equal as well las significant enhancement of NYHA status of the patients.

Peripheral Venous Pressure to Predict Congestive Heart Failure Readmission

Introduction Acute decompensated heart failure (ADHF) readmission rates are high and act as a burden to both the patient and the healthcare system. Non-invasive measures of hemodynamic status are limited in accuracy, leading to patients being discharged with residual congestion and a higher likelihood of subsequent readmission for ADHF. Peripheral venous pressure (PVP) measurement involves transducing a peripheral intravenous (PIV) catheter and may serve as a minimally invasive method of determining hemodynamic status in patients with ADHF. PVP measurements have been shown to correlate with CVP measurements in heart failure patients, but the clinical relevance of this has not yet been established. We sought to examine if PVP measurements may predict heart failure readmission. Methods A prospective feasibility study was conducted from July to December 2018. Patients admitted with ADHF were enrolled on day-of-discharge. Using a standard pressure transducer leveled to the phlebostatic access, measurement of PVP was performed at the bedside using a previously-inserted PIV. The electronic medical record was reviewed for subsequent readmissions. The primary end-point was readmission at 30 days post-discharge. Results 29 patients were enrolled. The mean age of participants was 65.6 +/- 10.8 years. 66% of patients were male and 55% of patients were black. 72% of patients had a reduced ejection fraction (EF) and 28% had a preserved EF. At the time of discharge, the mean PVP was 11.6 +/- 4.9 mmHg. 5 patients (17%) were readmitted within 30 days. Mean PVP for those readmitted was 12.0 +/- 2.1 mmHg vs 11.5 +/- 5.3 mmHg for those without readmission (difference of the means 0.5 mmHg, p= 0.86). PVP was not significantly impacted by whether a 22-gauge or 20-gauge PIV was used (difference of means 2.3 mmHg, p= 0.51). Waveform analysis on a subset of patients showed lower PVP in those with a sinusoidal waveform as opposed to a flatline or static waveform (12.8 vs. 17.4 mmHg, p=0.32). Conclusion In this small feasibility study, few patients were readmitted for heart failure in 30 days. PVP was similar among the 5 patients readmitted with ADHF. PVP measurement was readily obtainable and PVP was not significantly impacted by PIV gauge. Further study of this clinical application to PVP measurement is warranted.

Lessons learned measuring peripheral venous pressure waveforms in an anesthetized pediatric population

Objectives: The purpose is to describe our institution’s experience with collecting peripheral venous pressure (PVP) waveforms using a standard peripheral intravenous catheter in a pediatric patient under general anesthesia. Approach: PVP waveforms, piezoelectric monitoring, arterial blood pressure recording, and electrocardiogram (EKG) tracings were collected from patients undergoing cranial vault reconstruction for craniosynostosis. Data was obtained prospectively in a continuous manner from time of patient final positioning to closure of incision. Description of the technical aspects are discussed. Main Results: The waveform data collection was affected by the following: use of electrocautery, location of electrocautery in relation to PVP monitor, and movement of the operating room table. Significance: PVP waveforms can be collected in a pediatric patient undergoing general anesthesia with accurate data acquisition. Additionally, the set-up used also allows for accurate collecting of piezoelectric monitoring, arterial blood pressure recording, and EKG tracings in real time.

Fast Fourier Transformation of Peripheral Venous Pressure Changes More Than Vital Signs with Hemorrhage.

Vital signs are included in the determination of shock secondary to hemorrhage; however, more granular predictors are needed. We hypothesized that fast Fourier transformation (FFT) would have a greater percent change after hemorrhage than heart rate (HR) or systolic blood pressure (SBP). Using a porcine model, nine 17 kg pigs were hemorrhaged 10% of their calculated blood volume. Peripheral venous pressure waveforms, HR and SBP were collected at baseline and after 10% blood loss. FFT was performed on the peripheral venous pressure waveforms and the peak between 1 and 3 hertz (f1) corresponded to HR. To normalize values for comparison, percent change was calculated for f1, SBP, and HR. The mean percent change for f1 was an 18.8% decrease; SBP was a 3.31% decrease; and HR was a 0.95% increase. Using analysis of variance, FFT at f1 demonstrates a statistically significant greater change than HR or SBP after loss of 10% of circulating blood volume (p = 0.0023). Further work is needed to determine if this could be used in field triage to guide resuscitation.

Venous Physiology Predicts Dehydration in the Pediatric Population

BackgroundNo standard dehydration monitor exists for children. This study attempts to determine the utility of Fast Fourier Transform (FFT) of a peripheral venous pressure (PVP) waveform to predict dehydration. Materials and methodsPVP waveforms were collected from 18 patients. Groups were defined as resuscitated (serum chloride ≥ 100 mmol/L) and hypovolemic (serum chloride < 100 mmol/L). Data were collected on emergency department admission and after a 20 cc/kg fluid bolus. The MATLAB (MathWorks) software analyzed nonoverlapping 10-s window signals; 2.4 Hz (144 bps) was the most demonstrative frequency to compare the PVP signal power (mmHg). ResultsAdmission FFTs were compared between 10 (56%) resuscitated and 8 (44%) hypovolemic patients. The PVP signal power was higher in resuscitated patients (median 0.174 mmHg, IQR: 0.079-0.374 mmHg) than in hypovolemic patients (median 0.026 mmHg, IQR: 0.001-0.057 mmHg), (P < 0.001). Fourteen patients received a bolus regardless of laboratory values: 6 (43%) resuscitated and 8 (57%) hypovolemic. In resuscitated patients, the signal power did not change significantly after the fluid bolus (median 0.142 mmHg, IQR: 0.032-0.383 mmHg) (P = 0.019), whereas significantly increased signal power (median 0.0474 mmHg, IQR: 0.019-0.110 mmHg) was observed in the hypovolemic patients after a fluid bolus at 2.4 Hz (P < 0.001). The algorithm predicted dehydration for window-level analysis (sensitivity 97.95%, specificity 93.07%). The algorithm predicted dehydration for patient-level analysis (sensitivity 100%, specificity 100%). ConclusionsFFT of PVP waveforms can predict dehydration in hypertrophic pyloric stenosis. Further work is needed to determine the utility of PVP analysis to guide fluid resuscitation status in other pediatric populations.