Comparison of clinical symptoms and bioimpedance to pulmonary capillary wedge pressure in heart failure.

Introduction: Clinical symptoms of heart failure commonly include fatigue, edema, and shortness of breath. Unfortunately, clinical monitoring has proven unreliable in predicting congestion and the need for hospitalization. Biosensing wearables have been developed as a potential adjunct to clinical signs and symptoms to detect congestion before it becomes severe thus preventing a heart failure hospitalization. Hypothesis: Clinical signs and symptoms of heart failure will correlate with thoracic bioimpedance measurements (ZOE®) and pulmonary capillary wedge pressure (PCWP). Methods: One hundred and fifty-five subjects undergoing right heart catheterization (RHC) were prospectively enrolled. A Zo value (ohms) was obtained, jugular venous pressure (JVP) was estimated, edema graded, and shortness of breath (SOB) assessed in all subjects. RHC was performed by a scheduled cardiologist per routine. One-way ANOVA was performed to assess the relationship between variables. A Pearson correlation coefficient was used to compare the Zo value and PCWP. Results: Neither estimated JVP (cmH2O) (p = 0.65, n = 110) nor edema scores (p = 0.12, n = 110) demonstrated a significant relationship to PCWP. The presence of subjective SOB also did not demonstrate a significant association with PCWP (p = 0.99, n = 110). There was no correlation between ZOE® and PCWP (r = -0.08, p = 0.56, n = 56). Conclusions: These findings support the idea that traditional measures for monitoring heart failure patients are limited.

Hemodynamic Parameters in the Assessment of Fluid Status in a Porcine Hemorrhage and Resuscitation Model.

BACKGROUND: Measuring fluid status during intraoperative hemorrhage is challenging, but detection and quantification of fluid overload is far more difficult. Using a porcine model of hemorrhage and over-resuscitation, it is hypothesized that centrally obtained hemodynamic parameters will predict volume status more accurately than peripherally obtained vital signs. METHODS: Eight anesthetized female pigs were hemorrhaged at 30 ml/min to a blood loss of 400 ml. After each 100 ml of hemorrhage, vital signs (heart rate, systolic blood pressure, mean arterial pressure, diastolic blood pressure, pulse pressure, pulse pressure variation) and centrally obtained hemodynamic parameters (mean pulmonary artery pressure, pulmonary capillary wedge pressure, central venous pressure, cardiac output) were obtained. Blood volume was restored, and the pigs were over-resuscitated with 2,500 ml of crystalloid, collecting parameters after each 500-ml bolus. Hemorrhage and resuscitation phases were analyzed separately to determine differences among parameters over the range of volume. Conformity of parameters during hemorrhage or over-resuscitation was assessed. RESULTS: During the course of hemorrhage, changes from baseline euvolemia were observed in vital signs (systolic blood pressure, diastolic blood pressure, and mean arterial pressure) after 100 ml of blood loss. Central hemodynamic parameters (mean pulmonary artery pressure and pulmonary capillary wedge pressure) were changed after 200 ml of blood loss, and central venous pressure after 300 ml of blood loss. During the course of resuscitative volume overload, changes were observed from baseline euvolemia in mean pulmonary artery pressure and central venous pressure after 500-ml resuscitation, in pulmonary capillary wedge pressure after 1,000-ml resuscitation, and cardiac output after 2,500-ml resuscitation. In contrast to hemorrhage, vital sign parameters did not change during over-resuscitation. The strongest linear correlation was observed with pulmonary capillary wedge pressure in both hemorrhage (r2 = 0.99) and volume overload (r2 = 0.98). CONCLUSIONS: Pulmonary capillary wedge pressure is the most accurate parameter to track both hemorrhage and over-resuscitation, demonstrating the unmet clinical need for a less invasive pulmonary capillary wedge pressure equivalent.

Effects of an anesthesia perioperative surgical home for total knee and hip arthroplasty at a Veterans Affairs Hospital: a quality improvement before-and-after cohort study.

BACKGROUND: A perioperative surgical home, the Anesthesia Perioperative Care Service (APCS), was created to execute enhanced recovery after surgery pathways for total knee and total hip arthroplasty patients at the Tennessee Valley Health System Nashville VA Medical Center. We hypothesized that the APCS would be associated with reduced length of stay, in-hospital and post-discharge opioid exposure, costs, and hospital readmissions. METHODS: Data were collected for all patients admitted to the Nashville VA Medical Center following their respective surgery, for 400 days after the initiation of the APCS and for a 400-day period prior. This cohort study was based on a quality improvement project set up at the initiation of the service. The adjusted effect on each quantitative outcome was evaluated using proportional odds logistic regression methods. In addition, each regression analysis was performed in segmented regression fashion to identify changes in the outcomes over time. RESULTS: We included 282 patients in our cohort-96 prior and 186 post-implementation. Median hospital length of stay, intravenous (IV) and per os (PO) inpatient opioid administration, outpatient opioid quantity, and total days of supply were all reduced in the cohort cared for by the APCS. After adjusting for potential cofounders and evaluated outcome over time, the APCS remained independently associated with a reduction of hospital length of stay of one day (95% confidence interval, 0.09 to 1.97; P = 0.05) and with decreased IV and PO inpatient opioid administration, while continuing to show no increase in hospital readmissions. CONCLUSIONS: This cohort study showed significant improvements in important post-surgical outcomes after total knee and hip arthroplasty that were associated with the implementation of an APCS.

RéSUMé: CONTEXTE: Un centre de soins chirurgicaux périopératoires (perioperative surgical home), le Service de soins périopératoires en anesthésie (SSPA), a été créé pour mettre en œuvre des trajectoires de soins de récupération rapide après la chirurgie pour les patients ayant subi une arthroplastie totale du genou ou de la hanche au centre médical Tennessee Valley Health System Nashville VA Medical Center. Nous avons émis l'hypothèse que le SSPA serait associé à une réduction de la durée du séjour, de l'exposition aux opioïdes à l'hôpital et après le congé, ainsi qu'à une diminution des coûts et des réadmissions à l'hôpital. MéTHODE: Les données ont été recueillies pour tous les patients admis au centre médical Nashville VA Medical Center après leur chirurgie respective, pendant 400 jours avant et après la création du SSPA. Cette étude de cohorte se fondait sur un projet d'amélioration de la qualité mis en place lors de l'inauguration du service. L'effet ajusté sur chaque résultat quantitatif a été évalué à l'aide de méthodes de régression logistique proportionnelles. De plus, chaque analyse de régression a été effectuée de façon segmentée afin d'identifier l'évolution des résultats au fil du temps. RéSULTATS: Nous avons inclus 282 patients dans notre cohorte ­ 96 avant et 186 après la mise en œuvre. La durée médiane du séjour à l'hôpital, l'administration d'opioïdes par voie intraveineuse (IV) et per os (PO) pendant le séjour hospitalier, la quantité d'opioïdes en ambulatoire et sa durée en jours ont tous été réduites dans la cohorte prise en charge par le SSPA. Après avoir procédé à des ajustements pour tenir compte des facteurs de confusion potentiels et évalué l'évolution des résultats au fil du temps, le SSPA est demeuré indépendamment associé à une réduction de la durée de séjour à l'hôpital d'un jour (intervalle de confiance 95 %, 0,09 à 1,97; P = 0,05), à une réduction de l'administration d'opioïdes IV et PO durant le séjour, et il n'y a eu aucune augmentation des réadmissions à l'hôpital. CONCLUSION: Cette étude de cohorte a montré des améliorations significatives en matière de résultats post-chirurgicaux importants après une arthroplastie totale du genou et de la hanche associés à la mise en œuvre d'un SSPA.

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 brief report on the effects of vasoactive agents on peripheral venous waveforms in a porcine model.

OBJECTIVES: Non-invasive venous waveform analysis (NIVA) is a recently described, novel technique to assess intravascular volume status. Waveforms are captured with a piezoelectric sensor; analysis in the frequency domain allows for calculation of a "NIVA value" that represents volume status. The aim of this report was to determine the effects of vasoactive agents on the venous waveform and calculated NIVA values. DESIGN: Porcine experimental model. SETTING: Operating theatre. PARTICIPANTS: A piezoelectric sensor was secured over the surgically exposed saphenous vein in eight anesthetized pigs. MAIN OUTCOME MEASURES: NIVA value, pulmonary capillary wedge pressure (PCWP), and mean arterial pressure prior to and post intravenous administration of 150-180 µg of phenylephrine or 100 µg of sodium nitroprusside. RESULTS: Phenylephrine led to a decrease in NIVA value (mean 9.2 vs. 4.6, p < 0.05), while sodium nitroprusside led to an increase in NIVA value (mean 9.5 vs. 11.9, p < 0.05). Mean arterial pressure increased after phenylephrine (p < 0.05) and decreased after sodium nitroprusside (p < 0.05). PCWP did not change significantly after phenylephrine (p = 0.25) or sodium nitroprusside (p = 0.06). CONCLUSIONS: Vasoactive agents lead to changes in non-invasively obtained venous waveforms in euvolemic pigs, highlighting a potential limitation in the ability to NIVA to estimate static volume in this setting. Further studies are indicated to understand the effects of vasoactive agents in the setting of hypovolemia and hypervolemia.

Creation and Execution of a Novel Anesthesia Perioperative Care Service at a Veterans Affairs Hospital.

Physician-led perioperative surgical home models are developing as a method for improving the American health care system. These models are novel, team-based approaches that help to provide continuity of care throughout the perioperative period. Another avenue for improving care for surgical patients is the use of enhanced recovery after surgery pathways. These are well-described methods that have shown to improve perioperative outcomes. An established perioperative surgical home model can help implementation, efficiency, and adherence to enhanced recovery after surgery pathways. For these reasons, the Tennessee Valley Healthcare System, Nashville Veterans Affairs Medical Center created an Anesthesiology Perioperative Care Service that provides comprehensive care to surgical patients from their preoperative period through the continuum of their hospital course and postdischarge follow-up. In this brief report, we describe the development, implementation, and preliminary outcomes of the service.

ECG-based signal analysis technologies for evaluating patients with acute coronary syndrome: a systematic review.

BACKGROUND/OBJECTIVES: Timely identification of cardiac ischemia is critical in patients with acute coronary syndrome (ACS). The first test is often the standard, resting 12-lead ECG. Given its limitations, signal analysis enhancements have been proposed. We summarize the published evidence for commercially available ECG-based signal analysis technologies. METHODS: This is a systematic review of the English-language published literature. RESULTS: Published evidence meeting inclusion criteria was available for two devices: PRIME ECG and LP 3000. Meta-analysis of eight studies estimated a 68.4% sensitivity (95% CI, 35.1%-89.7%) and 91.4% specificity (CI, 83.6%-95.7%) for the PRIME ECG, compared with 40.5% sensitivity (CI, 19.6%-65.5%) and 95.0% specificity (CI, 87.9%-98.0%) for the standard 12-lead ECG. CONCLUSIONS: Existing evidence is insufficient to confidently inform the appropriate use of ECG-based signal analysis technologies for detecting ischemia or infarct in ACS. Further research is needed to determine in what circumstances, if any, these devices might precede, replace, or add to the standard ECG in test strategies for detecting ischemia or infarct in ACS.