A comparison of different methods to maximise signal extraction when using central venous pressure to optimise atrioventricular delay after cardiac surgery

Objective

Our group has shown that central venous pressure (CVP) can optimise atrioventricular (AV) delay in temporary pacing (TP) after cardiac surgery. However, the signal-to-noise ratio (SNR) is influenced both by the methods used to mitigate the pressure effects of respiration and the number of heartbeats analysed. This paper systematically studies the effect of different analysis methods on SNR to maximise the accuracy of this technique.

Methods

We optimised AV delay in 16 patients with TP after cardiac surgery. Transitioning rapidly and repeatedly from a reference AV delay to different tested AV delays, we measured pressure differences before and after each transition. We analysed the resultant signals in different ways with the aim of maximising the SNR: (1) adjusting averaging window location (around versus after transition), (2) modifying window length (heartbeats analysed), and (3) applying different signal filtering methods to correct respiratory artefact.

Results

(1) The SNR was 27 % higher for averaging windows around the transition versus post-transition windows. (2) The optimal window length for CVP analysis was two respiratory cycle lengths versus one respiratory cycle length for optimising SNR for arterial blood pressure (ABP) signals. (3) Filtering with discrete wavelet transform improved SNR by 62 % for CVP measurements. When applying the optimal window length and filtering techniques, the correlation between ABP and CVP peak optima exceeded that of a single cycle length (R = 0.71 vs. R = 0.50, p < 0.001).

Conclusion

We demonstrated that utilising a specific set of techniques maximises the signal-to-noise ratio and hence the utility of this technique.

Clinical value of CVP+VIVC in predicting fluid resuscitation in patients with septic shock

Objective

To explore the clinical value of central venous pressure (CVP) + inferior vena cava respiratory variability (VIVC) in fluid resuscitation in spontaneously breathing patients with septic shock.

Methods

In retrospective observational study, during October 2019 to December 2021, 145 patients with septic shock treated in our hospital were enrolled by the method of observational study. According to the change rate of cardiac output (ΔCO) ≥15% or ΔCO<15% after 30 minutes, they were assigned into volume-responsive and volume-unresponsive group depending early fluid resuscitation in sepsis. The clinical value of combination of CVP and VIVC in predicting fluid resuscitation in patients with septic shock was compared.

Results

The CVP of the study group was higher at 12h and 24h after fluid resuscitation, and the VIVC level of the study group at 6h, 12h and 24h after fluid resuscitation was higher (P<0.05). Pearson correlation analysis indicated that CVP, and VIVC levels were noticeably correlated with fluid resuscitation in patients with septic shock (P<0.05). The area under curve (AUC) of receiver operating characteristic curve (ROC) of CVP for predicting fluid resuscitation in septic shock patients was 0.694 and the cut-off value was 0.932, the sensitivity was 46.9%, and the specificity was 87.5%. VIVC predicted fluid resuscitation in septic shock patients with an AUC of 0.776, which was a cut-off value of 0.688, a sensitivity of 50.0%, and a specificity of 90.0%. Combination of CVP and VIVC predicted fluid resuscitation in septic shock patients with an AUC of 0.948, which was a cut-off value of 1.420, a sensitivity of 90.6%, and a specificity of 87.5%.

Conclusion

Combination of CVP and VIVC may have a good effect on the evaluation of volume responsiveness in patients with septic shock, which is better than single CVP and VIVC. Combination of CVP and VIVC can be adopted to predict fluid responsiveness volume responsiveness in septic shock patients, which is of great significance for guiding clinical fluid responsiveness therapy.

Comparing the associations of central venous pressure and pulmonary artery pulsatility index with postoperative renal injury

Objective

Cardiac surgery-associated acute kidney injury (CS-AKI) is associated with significant morbidity and mortality. We investigated the association of postoperative central venous pressure (CVP) and pulmonary artery pulsatility index (PAPi) with the development of CS-AKI.

Methods

This was a single-center, retrospective cohort study of patients undergoing cardiac surgery. CVP and PAPi were acquired hourly postoperatively and averaged for up to 48 h. PAPi was calculated as [(Pulmonary Artery Systolic Pressure–Pulmonary Artery Diastolic Pressure) / CVP]. The primary aim was CS-AKI. Secondary aims were need for renal replacement therapy (RRT), hospital and 30-day mortality, total ventilator and intensive care unit hours, and hospital length of stay. Logistic regression was used to calculate odds of development of renal injury and need for RRT.

Results

One thousand two hundred eighty-eight patients were included. The average postoperative CVP was 10.3 mmHg and average postoperative PAPi was 2.01. Patients who developed CS-AKI (n = 384) had lower PAPi (1.79 vs. 2.11, p < 0.01) and higher CVP (11.5 vs. 9.7 mmHg, p < 0.01) than those who did not. Lower PAPi and higher CVP were also associated with each secondary aim. A standardized unit decrease in PAPi was associated with increased odds of CS-AKI (OR 1.39, p < 0.01) while each unit increase in CVP was associated with both increased odds of CS-AKI (OR 1.56, p < 0.01) and postoperative RRT (OR 1.49, p = 0.02).

Conclusions

Both lower PAPi and higher CVP values postoperatively were associated with the development of CS-AKI but only higher CVP was associated with postoperative RRT use. When differences in values are standardized, CVP may be more associated with development of CS-AKI when compared to PAPi.

Central Venous Pressure Measurement Is Associated With Improved Outcomes in Patients With or at Risk for Acute Respiratory Distress Syndrome: An Analysis of the Medical Information Mart for Intensive Care IV Database

Background

Central venous pressure (CVP) monitoring is widely used in the intensive care unit (ICU). However, the formal utility of CVP measurement to altering patient outcomes among ICU patients with or at risk for acute respiratory distress syndrome (ARDS) has never been investigated. Our study aimed to explore the association of CVP measurement with 28-day mortality specifically in that population.

Methods

This study was based on the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Patients were divided into CVP and no CVP groups according to whether they had CVP measurement within 24 h of admission to the ICU. The primary outcome was 28-day mortality. Multivariate regression was used to elucidate the association between CVP measurement and 28-day mortality, and propensity score matching (PSM) and propensity score-based overlap weighting (OW) were employed to verify the stability of our results.

Results

A total of 10,198 patients with or at risk for ARDS were included in our study, of which 4,647 patients (45.6%) belonged to the CVP group. Multivariate logistic regression showed that the early measurement of CVP was independently associated with lower 28-day mortality (OR: 0.49; 95% CI: 0.42–0.57; p < 0.001). This association remained robust after PSM and OW (both p < 0.001). Patients in the CVP group had shorter ICU stay, lower in-hospital mortality, more fluid on day 1 and higher clearance of blood lactate than those in the no CVP group.

Conclusion

Early CVP measurement is associated with an improvement in 28-day mortality among a general population of critically ill patients with or at risk for ARDS.

Measuring the ratio of femoral vein diameter to femoral artery diameter by ultrasound to estimate volume status

Background

Currently, the accepted effective method for assessing blood volume status, such as measuring central venous pressure (CVP) and mean pulmonary artery pressure (mPAP), is invasive. The purpose of this study was to explore the feasibility and validity of the ratio of the femoral vein diameter (FVD) to the femoral artery diameter (FAD) for predicting CVP and mPAP and to calculate the cut-off value for the FVD/FAD ratio to help judge a patient’s fluid volume status.

Methods

In this study, 130 patients were divided into two groups: in group A, the FVD, FAD, and CVP were measured, and in group B, the FVD, FAD, and mPAP were measured. We measured the FVD and FAD by ultrasound. We monitored CVP by a central venous catheter and mPAP by a Swan-Ganz floating catheter. Pearson correlation coefficients were calculated. The best cut-off value for the FVD/FAD ratio for predicting CVP and mPAP was obtained according to the receiver operating characteristic (ROC) curve.

Results

The FVD/FAD ratio was strongly correlated with CVP (R = 0.87, P < 0.0000) and mPAP (R = 0.73, P < 0.0000). According to the ROC curve, an FVD/FAD ratio ≥ 1.495 had the best test characteristics to predict a CVP ≥ 12 cmH₂O, and an FVD/FAD ratio ≤ 1.467 had the best test characteristics to predict a CVP ≤ 10 cmH₂O. An FVD/FAD ratio ≥ 2.03 had the best test characteristics to predict an mPAP ≥ 25 mmHg. According to the simple linear regression curve of the FVD/FAD ratio and CVP, when the predicted CVP ≤ 5 cmH₂O, the FVD/FAD ratio was ≤ 0.854.

Conclusion

In this study, the measurement of the FVD/FAD ratio obtained via ultrasound was strongly correlated with CVP and mPAP, providing a non-invasive method for quickly and reliably assessing blood volume status and providing good clinical support.

Central venous pressure monitoring in critical care settings

Patients who present with acute cardiovascular compromise require haemodynamic monitoring in a critical care unit. Central venous pressure (CVP) is the most frequently used measure to guide fluid resuscitation in critically ill patients. It is most often done via a central venous catheter (CVC) positioned in the right atrium or superior or inferior vena cava as close to the right atrium as possible. The CVC is inserted via the internal jugular vein, subclavian vein or via the femoral vein, depending on the patient and their condition. Complications of CVC placement can be serious, so its risks and benefits need to be considered. Alternative methods to CVC use include transpulmonary thermodilution and transoesophageal Doppler ultrasound. Despite its widespread use, CVP has been challenged in many studies, which have reported it to be a poor predictor of haemodynamic responsiveness. However, it is argued that CVP monitoring provides important physiologic information for the evaluation of haemodynamic instability. Nurses have central roles during catheter insertion and in CVP monitoring, as well as in managing these patients and assessing risks.

GreenLight HPS laser 120 W vs diode laser 300 W vaporization of the prostate for the treatment of benign prostatic hyperplasia in Japanese patients: A prospective, single-center, randomized clinical trial

OBJECTIVES

This study aimed to compare the safety and efficacy of laser vaporization with 532 nm GreenLight High Performance System (HPS) laser 120 W (PVP) and 980 nm diode laser 300 W (CVP) for the treatment of benign prostatic hyperplasia (BPH) in a prospective, single-center, randomized clinical trial.

METHODS

A total of 153 consecutive patients with symptomatic BPH were included; 79 patients were treated with PVP and 74 with CVP. Patients were assessed preoperatively and at 3, 6, and 12 months postoperatively using the International Prostate Symptom Score, quality of life index, peak urinary flow rate, and postvoid residual urine volume. All perioperative and postoperative complications were noted.

RESULTS

There were significant and comparable improvements in each of the outcome variables over a follow-up period of 12 months in both groups. The mean operation/vaporization duration (minutes) was comparable at 74/38 (PVP) and 76/34 (CVP), whereas the mean applied laser energy was significantly higher with CVP than with PVP at 260 vs 195 (kJ), respectively. The mean vaporization rate (mL/min) was not significantly different between the two groups (0.53 PVP vs 0.56 CVP). Immediately after surgery, the rate of recatheterization for urinary retention was significantly higher with CVP than with PVP (17.6% vs 6.8%; P < 0.05).

CONCLUSIONS

Both laser systems provided comparable improvement in the subjective and objective parameters with excellent hemostatic properties. Although our results suggest that both procedures are useful treatment choices, further follow-up is needed to draw definitive conclusions regarding the most ideal laser for treating patients with symptomatic BPH.

Plant Virus Nanoparticles for Vaccine Applications

In the rapidly evolving field of nanotechnology, plant virus nanoparticles (pVNPs) are emerging as powerful tools in diverse applications ranging from biomedicine to materials science. The proteinaceous structure of plant viruses allows the capsid structure to be modified by genetic engineering and/or chemical conjugation with nanoscale precision. This means that pVNPs can be engineered to display peptides and proteins on their external surface, including immunodominant peptides derived from pathogens allowing pVNPs to be used for active immunization. In this context, pVNPs are safer than VNPs derived from mammalian viruses because there is no risk of infection or reversion to pathogenicity. Furthermore, pVNPs can be produced rapidly and inexpensively in natural host plants or heterologous production platforms. In this review, we discuss the use of pVNPs for the delivery of peptide antigens to the host immune in pre-clinical studies with the final aim of promoting systemic immunity against the corresponding pathogens. Furthermore, we described the versatility of plant viruses, with innate immunostimulatory properties, in providing a huge natural resource of carriers that can be used to develop the next generation of sustainable vaccines.

[Central venous pressure in liver surgery : A primary therapeutic goal or a hemodynamic tessera?]

Central venous pressure (CVP) is deemed to be an important parameter of anesthesia management in liver surgery. To reduce blood loss during liver resections, a low target value of CVP is often propagated. Although current meta-analyses have shown a connection between low CVP and a reduction in blood loss, the underlying studies show methodological weaknesses and advantages with respect to morbidity and mortality can hardly be proven. The measurement of the CVP itself is associated with numerous limitations and influencing factors and the measures to reduce the CVP have been insufficiently investigated with respect to hepatic hemodynamics. The definition of a generally valid target area for the CVP must be called into question. The primary objective is to maintain adequate oxygen supply and euvolemia. The CVP should be regarded as a mosaic stone of hemodynamic management.

The Correlation Between Inferior Vena Cava Diameter Measured by Ultrasonography and Central Venous Pressure

OBJECTIVE

To find a correlation between inferior vena cava (IVC) diameters, IVC compressibility index (CI) and central venous pressure (CVP).

METHODS

Prospective observational study was done at pediatric intensive care unit (PICU) of Kalawati Saran Children's Hospital (KSCH). Fifty children aged 5-18 y, presenting with shock were enrolled for the study. IVC diameters, CI and relevant clinical data were noted at enrollment, 30 min, 1 h, 6 h, and 12 h. Central line was placed at the time of admission.

RESULTS

Of 50 children enrolled, 28 were boys, with a mean age of 11 y. More than 80% of cases were diagnosed as septic shock. Mean maximum and minimum IVC diameter of 8.3 ± 2 mm and 3.7 ± 1.7 mm, respectively CI 58.2 ± 7% and CVP of 5.4 ± 1.5 cm of H₂O was observed at admission. CVP and IVC diameters showed a serial improvement with treatment; CI showed a serial decrease with treatment. Heart rate (HR) and systolic blood pressure (SBP) also showed a serial improvement at 12 h (p < 0.05). CVP showed a positive correlation with IVC diameter (r +0.312; p < 0.05), and a negative correlation with CI (r -0.343; p < 0.05).

CONCLUSIONS

Effective fluid resuscitation improves IVC diameters with a decrease in CI. IVC diameter has a positive correlation to CVP and CI has a negative correlation to CVP.

Multiple Cranial Organ Defects after Conditionally Knocking Out Fgf10 in the Neural Crest

Fgf10 is necessary for the development of a number of organs that fail to develop or are reduced in size in the null mutant. Here we have knocked out Fgf10 specifically in the neural crest driven by Wnt1cre. The Wnt1creFgf10fl/fl mouse phenocopies many of the null mutant defects, including cleft palate, loss of salivary glands, and ocular glands, highlighting the neural crest origin of the Fgf10 expressing mesenchyme surrounding these organs. In contrast tissues such as the limbs and lungs, where Fgf10 is expressed by the surrounding mesoderm, were unaffected, as was the pituitary gland where Fgf10 is expressed by the neuroepithelium. The circumvallate papilla of the tongue formed but was hypoplastic in the conditional and Fgf10 null embryos, suggesting that other sources of FGF can compensate in development of this structure. The tracheal cartilage rings showed normal patterning in the conditional knockout, indicating that the source of Fgf10 for this tissue is mesodermal, which was confirmed using Wnt1cre-dtTom to lineage trace the boundary of the neural crest in this region. The thyroid, thymus, and parathyroid glands surrounding the trachea were present but hypoplastic in the conditional mutant, indicating that a neighboring source of mesodermal Fgf10 might be able to partially compensate for loss of neural crest derived Fgf10.

A Review of Central Venous Pressure and Its Reliability as a Hemodynamic Monitoring Tool in Veterinary Medicine

OBJECTIVE

To review the current literature regarding central venous pressure (CVP) in veterinary patients pertaining to placement (of central line), measurement, interpretation, use in veterinary medicine, limitations, and controversies in human medicine.

ETIOLOGY

CVP use in human medicine is a widely debated topic, as numerous sources have shown poor correlation of CVP measurements to the volume status of a patient. Owing to the ease of placement and monitoring in veterinary medicine, CVP remains a widely used modality for evaluating the hemodynamic status of a patient. A thorough evaluation of the veterinary and human literature should be performed to evaluate the role of CVP measurements in assessing volume status in veterinary patients.

DIAGNOSIS

Veterinary patients that benefit from accurate CVP readings include those suffering from hypovolemic or septic shock, heart disease, or renal disease or all of these. Other patients that may benefit from CVP monitoring include high-risk anesthetic patients undergoing major surgery, trending of fluid volume status in critically ill patients, patients with continued shock, and patients that require rapid or large amounts of fluids.

THERAPY

The goal of CVP use is to better understand a patient's intravascular volume status, which would allow early goal-directed therapy.

PROGNOSIS

CVP would most likely continue to play an important role in the hemodynamic monitoring of the critically ill veterinary patient; however, when available, cardiac output methods should be considered the first choice for hemodynamic monitoring.

Plant-Derived Chimeric Virus Particles for the Diagnosis of Primary Sjögren Syndrome

Plants are ideal for the production of protein-based nanomaterials because they synthesize and assemble complex multimeric proteins that cannot be expressed efficiently using other platforms. Plant viruses can be thought of as self-replicating proteinaceous nanomaterials generally stable and easily produced in high titers. We used Potato virus X (PVX), chimeric virus particles, and Cowpea mosaic virus, empty virus-like particles to display a linear peptide (lipo) derived from human lipocalin, which is immunodominant in Sjögren's syndrome (SjS) and is thus recognized by autoantibodies in SjS patient serum. These virus-derived nanoparticles were thus used to develop a diagnostic assay for SjS based on a direct enzyme linked immunosorbent assay format. We found that PVX-lipo formulations were more sensitive than the chemically synthesized immunodominant peptide and equally specific when used to distinguish between healthy individuals and SjS patients. Our novel assay therefore allows the diagnosis of SjS using a simple, low-invasive serum test, contrasting with the invasive labial biopsy required for current tests. Our results demonstrate that nanomaterials based on plant viruses can be used as diagnostic reagents for SjS, and could also be developed for the diagnosis of other diseases.

Precision of echocardiographic estimates of right atrial pressure in patients with acute decompensated heart failure

BACKGROUND

Several methods that estimate right atrial pressure (RAP) from echocardiographic parameters have been proposed. However, their precision (i.e., how much they decrease RAP estimation uncertainty) is unknown. The aim of this prospective study was to evaluate and compare the precision of previously proposed RAP estimates in patients with acute decompensated heart failure.

METHODS

Echocardiographic and invasive hemodynamic data were acquired in 75 patients with acute decompensated heart failure. Measurements were made at the start and 48 to 72 hours after the beginning of treatment. RAP was estimated by method 1, using the cutoffs defined by inferior vena cava diameter (IVCd) and IVCd percentage change (IVCd%change) during inspiration, and by method 2, using IVCd%change and systolic to diastolic hepatic flow ratio (S/Dhep). Method 3 was used in patients with sinus rhythm, using the ratio of early tricuspid inflow and early diastolic tissue Doppler tricuspid annular velocities (E/E'ta). RAP was also estimated by resting IVCd, IVCd during inspiration, IVCd%change, right ventricular regional isovolumetric relaxation time, E/E'ta, right atrial volume index, S/Dhep, right ventricular Tei index, right ventricular E/A, and right atrial emptying fraction. Precision gain was measured as the difference between the standard deviation of RAP and the standard error of the estimate of RAP.

RESULTS

Method 1 (r = 0.48, P < .05), IVCd during inspiration (r = 0.49, P < .0001), IVCd%change (r = 0.41, P < .0001) and IVCd (r = 0.40, P < .0001) had the highest correlation with RAP. The highest gain in precision was also observed with the above methods (9%, 13%, 9%, and 8%, respectively). All other parameters had poor correlation with RAP.

CONCLUSION

In patients with advanced heart failure, echocardiographic RAP prediction methods showed only modest precision. Furthermore, none of the tested methods resulted in clinically relevant improvements of RAP estimates. Estimating RAP from a single IVCd measurement is at least as precise as using complex prediction methods.

The relationship between inferior vena cava diameter measured by bedside ultrasonography and central venous pressure value

Objective: We aimed to present inferior vena cava (IVC) diameter as a guiding method for detection of relationship between IVC diameter measured noninvasively with the help of ultrasonography (USG) and central venous pressure (CVP) and evaluation of patient's intravascular volume status.

Methods: Patients over the age of 18, to whom a central venous catheter was inserted to their subclavian vein or internal jugular vein were included in our study. IVC diameter measurements were recorded in millimeters following measurement by the same clinician with the help of USG both at the end-inspiratory and end-expiratory phase. CVP measurements were viewed on the monitor by means of piezoelectric transducer and recorded in mmHg. SPSS 18.0 package program was used for statistical analysis of data.

Results: Forty five patients were included in the study. The patients had the diagnosis of malignancy (35.6%), sepsis (13.3%), pneumonia, asthma, chronic obstructive pulmonary disease (11.1%). 11 patients (24.4%) required mechanical ventilation while 34 (75.6%) patients had spontaneous respiration. In patients with spontaneous respiration, a significant relationship was found between IVC diameters measured by ultrasonography at the end of expiratory and inspiratory phases and measured CVP values at the same phases (for expiratory p = 0.002, for inspiratory p= 0.001). There was no statistically significant association between IVC diameters measured by ultrasonography at the end of expiration and inspiration and measured CVP values at the same phases in mechanically ventilated patients.

Conclusions: IVC diameter measured by bedside ultrasonography can be used for determination of the intravascular volume status of the patients with spontaneous respiration.

3:1 compression to ventilation ratio versus continuous chest compression with asynchronous ventilation in a porcine model of neonatal resuscitation

OBJECTIVE

In contrast to the resuscitation guidelines of children and adults, guidelines on neonatal resuscitation recommend synchronized 90 chest compressions with 30 manual inflations (3:1) per minute in newborn infants. The study aimed to determine if chest compression with asynchronous ventilation improves the recovery of bradycardic asphyxiated newborn piglets compared to 3:1 Compression:Ventilation cardiopulmonary resuscitation (CPR).

INTERVENTION AND MEASUREMENTS

Term newborn piglets (n=8/group) were anesthetized, intubated, instrumented and exposed to 45-min normocapnic hypoxia followed by asphyxia. Protocolized resuscitation was initiated when heart rate decreased to 25% of baseline. Piglets were randomized to receive resuscitation with either 3:1 compressions to ventilations (3:1C:V CPR group) or chest compressions with asynchronous ventilations (CCaV) or sham. Continuous respiratory parameters (Respironics NM3(®)), cardiac output, mean systemic and pulmonary artery pressures, and regional blood flows were measured.

MAIN RESULTS

Piglets in 3:1C:V CPR and CCaV CPR groups had similar time to return of spontaneous circulation, survival rates, hemodynamic and respiratory parameters during CPR. The systemic and regional hemodynamic recovery in the subsequent 4h was similar in both groups and significantly lower compared to sham-operated piglets.

CONCLUSION

Newborn piglets resuscitated by CCaV had similar return of spontaneous circulation, survival, and hemodynamic recovery compared to those piglets resuscitated by 3:1 Compression:Ventilation ratio.

The incidence and significance of bacteremia in out of hospital cardiac arrest

BACKGROUND

The most common etiology of cardiac arrest is presumed of myocardial origin. Recent retrospective studies indicate that preexisting pneumonia, a form of sepsis, is frequent in patients who decompensate with abrupt cardiac arrest without preceding signs of septic shock, respiratory failure or severe metabolic disorders shortly after hospitalization. The contribution of pre-existing infection on pre and post cardiac arrest events remains unknown and has not been studied in a prospective fashion. We sought to examine the incidence of pre-existing infection in out-of hospital cardiac arrest (OHCA) and assess characteristics associated with bacteremia, the goal standard for presence of infection.

METHODS AND RESULTS

We prospectively observed 250 OHCA adult patients who presented to the Emergency Department (ED) between 2007 and 2009 to an urban academic teaching institution. Bacteremia was defined as one positive blood culture with non-skin flora bacteria or two positive blood cultures with skin flora bacteria. 77 met pre-defined exclusion criteria. Of the 173 OHCA adults, 65 (38%) were found to be bacteremic with asystole and PEA as the most common presenting rhythms. Mortality in the ED was significantly higher in bacteremic OHCA (75.4%) compared to non-bacteremic OHCA (60.2%, p<0.05). After adjustment for potential confounders, predictive factors associated with bacteremic OHCA were lower initial arterial pH, higher lactate, WBC, BUN and creatinine.

CONCLUSIONS

Over one-third of OHCA adults were bacteremic upon presentation. These patients have greater hemodynamic instability and significantly increased short-term mortality. Further studies are warranted to address the epidemiology of infection as possible cause of cardiac arrest.

Ductus venosus closure results in transient portal hypertension--is this the silent trigger for necrotizing enterocolitis?

INTRODUCTION

The etiology of necrotizing enterocolitis (NEC) remains elusive and no definite trigger has been identified. There are no studies to date examining the potential role of closure of the ductus venosus (DV), its effect on increasing portal venous pressure (PVP) and its association to mesenteric venous ischemia in the development of NEC. Our aim was to develop an animal model to examine this physiology.

METHODS

Fifteen near-term lambs were used. The DV was occluded in experimental animals by a balloon tip catheter, while the sham controls underwent catheterization without DV occlusion. Vital signs and PVP were monitored for 4h, followed by intestinal biopsy.

RESULTS

The experimental group (n=5) demonstrated a significant increase in PVP following DV occlusion (11.87 mm Hg [95% CI: 11.40-12.34]), compared to controls (8.95 mm Hg [95% CI: 8.34-9.56]) (F=12.16, p=0.001). Histology of the terminal ileum showed vacuolar degeneration, indicative of reversible cellular damage in the experimental group.

CONCLUSIONS

We demonstrate that DV closure in the neonatal lamb leads to transient portal hypertension which is associated with cellular damage and inflammatory changes of the intestinal mucosa. Additional studies will be necessary to determine if the transient portal hypertension following DV closure leads to clinically apparent intestinal ischemia and NEC.

A case of severe heatstroke and review of pathophysiology, clinical presentation, and treatment

Heatstroke is life-threatening condition characterized by hyperthermia and central nervous system disturbances. It can also be classified as a form of systemic inflammatory response syndrome with multiple organ dysfunction and in many ways resembles sepsis. Like sepsis, most patients with heatstroke demonstrate a hyperdynamic hemodynamic response. In contrast to sepsis, rhabdomyolysis may complicate management and initial fluid resuscitation is not well defined. We present an illustrative case report and review of literature.

Comparison of the central venous pressure from internal jugular vein and the pressure measured from the peripherally inserted antecubital central catheter (PICCP) in liver transplantation recipients

Background

Unlike its use during stable conditions, central venous pressure (CVP) monitoring from a peripherally inserted central venous catheter (PICC) has not often been used in surgeries with significant hemodynamic alterations. The aim of this study was to evaluate the feasibility of measuring PICC pressure (PICCP) as an alternative to measuring centrally inserted central catheter pressure (CICCP) in adult liver transplantation (LT) patients.

Methods

We measured PICCP and CICCP simultaneously during each main surgical period in adult LT. Statistical analysis was performed using simple linear regression analysis to observe whether changes in PICCP paralleled by simultaneous changes in CICCP. Correlation analysis and Bland-Altman analysis were used to determine the degree of agreement between the two devices. Differences were considered statistically significant when P values were less than 0.05.

Results

A total of 1342 data pairs were collected from 35 patients. The PICCPs and CICCPs were highly correlated overall (r = 0.970, P < 0.001) as well as at each period measured. The differences among each period were not clinically significant (0.33 mmHg for pre-anhepatic, 0.32 mmHg for anhepatic, -0.15 mmHg for reperfusion, and -0.10 mmHg for neohepatic periods). The overall mean difference was 0.14 mmHg (95% confidence interval: 0.09-0.19) and PICCP tended to give a higher reading by between 0.09 and 0.19 mmHg overall. The limit of agreement was -1.74 to 2.02 overall.

Conclusions

These findings suggest that PICCP can be a reasonable alternative to CICCP in situations of dynamic systemic compliance and preload, as well as under stable hemodynamic conditions.