Hemodynamic monitoring

The Influence of Food Intake and Preload Augmentation on Cardiac Functional Parameters: A Study Using Both Cardiac Magnetic Resonance and Echocardiography

(1) Background: To investigate how food intake and preload augmentation affect the cardiac output (CO) and volumes of the left ventricle (LV) and right ventricle (RV) assessed using cardiac magnetic resonance (CMR) and trans-thoracic echocardiography (TTE). (2) Methods: Eighty-two subjects with (n = 40) and without (n = 42) cardiac disease were assessed using both CMR and TTE immediately before and after a fast infusion of 2 L isotonic saline. Half of the population had a meal during saline infusion (food/fluid), and the other half were kept fasting (fasting/fluid). We analyzed end-diastolic (EDV) and end-systolic (ESV) volumes and feature tracking (FT) using CMR, LV global longitudinal strain (GLS), and RV longitudinal strain (LS) using TTE. (3) Results: CO assessed using CMR increased significantly in both groups, and the increase was significantly higher in the food/fluid group: LV-CO (ΔLV-CO: +2.6 ± 1.3 vs. +0.7 ± 1.0 p < 0.001), followed by increased heart rate (HR) (ΔHR: +12 ± 8 vs. +1 ± 6 p < 0.001). LV and RV achieved increased stroke volume (SV) through different mechanisms. For the LV, through increased contractility, increased LV-EDV, decreased LV-ESV, increased LV-FT, and GLS were observed. For the RV, increased volumes, increased RV-EDV, increased RV-ESV, and at least for the fasting/fluid group, unchanged RV-FT and RV-LS were reported. (4) Conclusions: Preload augmentation and food intake have a significant impact on hemodynamic and cardiac functional parameters. This advocates for standardized recommendations regarding oral intake of fluid and food before cardiac assessment, for example, TTE, CMR, and right heart catheterization. We also demonstrate different approaches for the LV and RV to increase SV: for the LV by increased contractility, and for the RV by volume expansion.

Intensive care drug therapy and its potential adverse effects on blood pressure and heart rate in critically ill children

BACKGROUND

Owing to complex treatment, critically ill children may experience alterations in their vital parameters. We investigated whether such hemodynamic alterations were temporally and causally related to drug therapy.

METHODS

In a university pediatric intensive care unit, we retrospectively analyzed hemodynamic alterations defined as values exceeding the limits set for heart rate (HR) and blood pressure (BP). For causality assessment, we used the World Health Organization-Uppsala Monitoring Center (WHO-UMC) system, which categorizes the probability of causality as "certain," "probable," "possible," and "unlikely."

RESULTS

Of 315 analyzed patients with 43,200 drug prescriptions, 59.7% experienced at least one hemodynamic alteration; 39.0% were affected by increased HR, 19.0% by decreased HR, 18.1% by increased BP, and 16.2% by decreased BP. According to drug information databases, 83.9% of administered drugs potentially lead to hemodynamic alterations. Overall, 88.3% of the observed hemodynamic alterations had a temporal relation to the administration of drugs; in 80.2%, more than one drug was involved. Based on the WHO-UMC system, a drug was rated as a "probable" causing factor for only 1.4% of hemodynamic alterations. For the remaining alterations, the probability ratings were lower because of multiple potential causes, e.g., several drugs.

CONCLUSIONS

Critically ill children were frequently affected by hemodynamic alterations. The administration of drugs with potentially adverse effects on hemodynamic parameters is often temporally related to hemodynamic alterations. Hemodynamic alterations are often multifactorial, e.g., due to administering multiple drugs in rapid succession; thus, the influence of individual drugs cannot easily be captured with the WHO-UMC system.

Haemodynamic monitoring in acute heart failure - what you need to know

Acute heart failure (AHF) is a sudden, life-threatening condition, defined as a gradual or rapid onset of symptoms and/or signs of HF. AHF requires urgent medical attention, being the most frequent cause of unplanned hospital admission in patients above 65 years of age. AHF is associated with a 4–12% in-hospital mortality rate and a 21–35% 1-year mortality rate post-discharge. Considering the serious prognosis in AHF patients, it is very important to understand the mechanisms and haemodynamic status in an individual AHF patient, thus preventing end-organ failure and death. Haemodynamic monitoring is a serial assessment of cardiovascular function, intended to detect physiologic abnormalities at the earliest stages, determine which interventions could be most effective, and provide the basis for initiating the most appropriate therapy and evaluate its effects. Over the past decades, haemodynamic monitoring techniques have evolved greatly. Nowadays, they range from very invasive to non-invasive, from intermittent to continuous, and in terms of the provided parameters. Invasive techniques contain pulmonary artery catheterization and transpulmonary thermodilution. Minimally invasive techniques include oesophageal Doppler and noncalibrated pulse wave analysis. Non-invasive techniques contain echocardiography, bioimpedance, and bioreactance techniques as well as non-invasive pulse contour methods. Each of these techniques has specific indications and limitations. In this article, we aimed to provide a pathophysiological explanation of the physical terms and parameters used for haemodynamic monitoring in AHF and to summarize the working principles, advantages, and disadvantages of the currently used methods of haemodynamic monitoring.

Updates in Hemodynamic Monitoring: A Review for Pharmacists

Vital signs are regularly monitored in hospitalized patients. In the intensive care unit (ICU), traditional non-invasive blood pressure monitoring and telemetry may not provide enough information to determine the etiology of hemodynamic instability or guide intervention. Arterial catheters remain the gold-standard for continuous blood pressure monitoring and are commonly used in ICU patients. Pulmonary artery catheters and central venous catheters are beneficial in select patient populations and provide more advanced and specific information about a patient's hemodynamics. However, neither are benign and can increase risk of complications such as infection, arrhythmias, pneumothorax and vascular or valvular damage. In the past 10 years, the development of reliable non-invasive (NICOM), or minimally-invasive (MICOM), cardiac output monitoring devices has accelerated. The MICOM devices require an arterial catheter to obtain hemodynamic values, whereas NICOM devices do not require any arterial or venous access. These devices have emerged to be particularly useful in evaluating and managing patients with suspected mixed shock. As these devices become more prevalent, it is imperative that clinical pharmacists become familiar with interpreting this data as it may have a substantial impact on medication selection and optimization. This review will discuss the basics of NICOM and MICOM devices, limitations with these methods of monitoring, and clinical application for pharmacists.

A Physiologic Approach to Hemodynamic Monitoring and Optimizing Oxygen Delivery in Shock Resuscitation

The approach to shock resuscitation focuses on all components of oxygen delivery, including preload, afterload, contractility, hemoglobin, and oxygen saturation. Resuscitation focused solely on preload and fluid responsiveness minimizes other key elements, resulting in suboptimal patient care. This review will provide a physiologic and practical approach for the optimization of oxygen delivery utilizing available hemodynamic monitoring technologies. Venous oxygen saturation (SvO₂) and lactate will be discussed as indicators of shock states and endpoints of resuscitation within the framework of resolving oxygen deficit and oxygen debt.

Non-invasive assessment of arterial pulsatility in patients with continuous-flow left ventricular assist devices

INTRODUCTION

Long-term use of continuous-flow left ventricular assist devices may have negative consequences for autonomic, cardiovascular and gastrointestinal function. It has thus been suggested that non-invasive monitoring of arterial pulsatility in patients with a left ventricular assist device is highly important for ensuring patient safety and longevity. We have developed a novel, semi-automated frequency-domain-based index of arterial pulsatility that is obtained during suprasystolic occlusions of the upper arm: the 'cuff pulsatility index'.

PURPOSE

The purpose of this study was to evaluate the relationship between the cuff pulsatility index and invasively determined arterial pulsatility in patients with a left ventricular assist device.

METHODS

Twenty-three patients with a left ventricular assist device with end-stage heart failure (six females: age = 65 ± 9 years; body mass index = 30.5 ± 3.7 kg m^-2) were recruited for this study. Suprasystolic occlusions were performed on the upper arm of the patient's dominant side, from which the cuff pressure waveform was obtained. Arterial blood pressure was obtained from the radial artery on the contralateral arm. Measurements were obtained in triplicate. The relationship between the cuff pressure and arterial blood pressure waveforms was assessed in the frequency-domain using coherence analysis. A mixed-effects approach was used to assess the relationship between cuff pulsatility index and invasively determined arterial pulsatility (i.e. pulse pressure).

RESULTS

The cuff pressure and arterial blood pressure waveforms demonstrated a high coherence up to the fifth harmonic of the cardiac frequency (heart rate). The cuff pulsatility index accurately tracked changes in arterial pulse pressure within a given patient across repeated measurements.

CONCLUSIONS

The cuff pulsatility index shows promise as a non-invasive index for monitoring residual arterial pulsatility in patients with a left ventricular assist device across time.

Vasoactive Agents for Adult Septic Shock: An Update and Review

PURPOSE

The objective of this article is to discuss the pharmacology, side effects, and clinical application of vasoactive therapy in the management of adult septic shock.

SUMMARY

Sepsis is one of the most common reasons for admission to an intensive care unit with the incidence estimated to be greater than 750 000 cases per year in the United States. Clinicians should understand the basic pharmacology of available vasoactive agents to allow for routine and complex management of septic shock.

CONCLUSION

While advances in research, identification, and early implementation of best practices for the treatment of sepsis has reduced mortality, rates remain high. Vasopressors and inotropes remain part of the core therapeutic modalities of sepsis management. Norepinephrine is the first-line vasopressor of choice for septic shock, though secondary vasopressors can be used depending on the patient's circumstances.

Noninvasive Blood Pressure Monitor Designed for Patients With Heart Failure Supported with Continuous-Flow Left Ventricular Assist Devices

The gold standard for noninvasive blood pressure (BP) measurement, the Doppler technique, does not provide systolic blood pressure (SBP) and diastolic blood pressure (DBP) and may limit therapy outcomes. To improve patient care, we tested specifically designed experimental BP (ExpBP) monitor and the Doppler technique by comparing noninvasive measures to the intraarterial (I-A) BP in 31 patients with end-stage heart failure (4 females) 2.6 ± 3.4 days post-LVAD implantation (20 HeartMate II and 11 HeartWare). Bland-Altman plots revealed that the ExpBP monitor overestimated mean arterial pressure (MAP) by 1.2 (4.8) mm Hg (mean difference [standard deviation]), whereas the Doppler by 6.7 (5.8) mm Hg. The ExpBP SBP was overestimated by 0.8 (6.1) mm Hg and DBP by 1.9 (5.3) mm Hg compared with the respective I-A pressures. Both techniques achieved similar measurement reliability. In the measurement "success rate" expressed as a frequency (percent) of readable BP values per measurement attempts, Doppler accomplished 100% vs. 97%, 97%, and 94% of successful detections of MAP, SBP, and DBP provided by the ExpBP monitor. The ExpBP monitor demonstrated higher accuracy in the MAP assessment than the Doppler in addition to providing SBP and DBP in majority of subjects. Improved BP control may help to mitigate related neurologic adverse event rates.

Evolved role of the cardiovascular intensive care unit (CICU)

Cardiovascular intensive care refers to special systemic management for the patients with severe cardiovascular disease (CVD), which consists of heart disease and vascular disease. CVD is one of the leading causes of death in the world. In order to prevent death due to CVDs, an intensive care unit for severe CVD patients, so-called cardiovascular intensive care unit (CICU), has been developed in many general hospitals. The technological developments of clinical cardiology, such as invasive hemodynamic monitoring and intracoronary interventional procedures and devices, have resulted in evolution of intensive care for CVDs. Subsequently, severe CVD patients admitted to CICU are increasing year by year. Dedicated medical staff is required for CICU in order to perform best patient management. It is necessary for optimal patient care to select effective means from various hemodynamic tools and to adjust the usage according to the clinical situation such as cardiogenic shock and acute heart failure. Furthermore, the patients in the CICU often have various complications such as respiratory failure and renal failure. Therefore, medical staffs who work at CICU are required to have the ability to practice systemic intensive care.

Intraoperative monitoring of stroke volume variation versus central venous pressure in laparoscopic liver surgery: a randomized prospective comparative trial

BACKGROUND

Central venous pressure (CVP) is used as a marker of cardiac preload to control intraoperative blood loss in open hepatectomies, while its reliability in laparoscopy is less certain. The aim of this randomized prospective trial was to evaluate the outcome of laparoscopic resections performed with stroke volume variation (SVV) or CVP monitoring.

METHODS

All candidates for laparoscopic liver resection were assigned randomly to SVV or to CVP groups. Outcome was evaluated included conversion rate, cause of conversion, intraoperative blood loss, need for transfusions, length of surgery and postoperative results.

RESULTS

Ninety consecutive patients were enrolled: both SVV and CVP groups included 45 patients each and were comparable in terms of patient and disease characteristics. A reduced rate of conversion was recorded in the SVV compared to the CVP group (6.7% and 17.8% respectively, p = 0.02). Blood loss was lower in the SVV group (150 mL), compared to the CVP group (300 mL, p = 0.04). Morbidity, mortality, length of stay and functional recovery were comparable. On multivariate analysis, lesion location, extent of hepatectomy and type of cardiac preload monitoring were associated significantly to risk of conversion.

CONCLUSION

SVV monitoring in laparoscopic liver surgery improves intraoperative outcome, thus enhancing the benefits of the minimally-invasive approach and fast-track protocols.

Effectiveness of treatment based on PiCCO parameters in critically ill patients with septic shock and/or acute respiratory distress syndrome: a randomized controlled trial

PURPOSE

To compare treatment based on either PiCCO-derived physiological values or central venous pressure (CVP) monitoring, we performed a prospective randomized controlled trial with group sequential analysis.

METHODS

Consecutive critically ill patients with septic shock and/or ARDS were included. The planned total sample size was 715. The primary outcome was 28-day mortality after randomization. Participants underwent stratified randomization according to the classification of ARDS and/or septic shock. Caregivers were not blinded to the intervention, but participants and outcome assessors were blinded to group assignment.

RESULTS

The study was stopped early because of futility after enrollment of 350 patients including 168 in the PiCCO group and 182 in the control group. There was no loss to follow-up and data from all enrolled participants were analyzed. The result showed that treatment based on PiCCO-derived physiological values was not able to reduce the 28-day mortality risk (odds ratio 1.00, 95 % CI 0.66-1.52; p = 0.993). There was no difference between the two groups in secondary outcomes such as 14-day mortality (40.5 vs. 41.2 %; p = 0.889), ICU length of stay (median 9 vs. 7.5 days; p = 0.598), days free of vasopressors (median 14.5 vs. 19 days; p = 0.676), and days free of mechanical ventilation (median 3 vs. 6 days; p = 0.168). No severe adverse event was reported in both groups.

CONCLUSION

On the basis of our study, PICCO-based fluid management does not improve outcome when compared to CVP-based fluid management.

Conventional hemodynamic resuscitation may fail to optimize tissue perfusion: an observational study on the effects of dobutamine, enoximone, and norepinephrine in patients with acute myocardial infarction complicated by cardiogenic shock

AIM

To investigate the effects of inotropic agents on parameters of tissue perfusion in patients with cardiogenic shock.

METHODS AND RESULTS

Thirty patients with cardiogenic shock were included. Patients received dobutamine, enoximone, or norepinephrine. We performed hemodynamic measurements at baseline and after titration of the inotropic agent until cardiac index (CI) ≥ 2.5 L.min-1.m(-2) or mixed-venous oxygen saturation (SvO2) ≥ 70% (dobutamine or enoximone), and mean arterial pressure (MAP) ≥ 70 mmHg (norepinephrine). As parameters of tissue perfusion, we measured central-peripheral temperature gradient (delta-T) and sublingual perfused capillary density (PCD). All patients reached predefined therapeutic targets. The inotropes did not significantly change delta-T. Dobutamine did not change PCD. Enoximone increased PCD (9.1 [8.9-10.2] vs. 11.4 [8.4-13.9] mm.mm(-2); p<0.05), and norepinephrine tended to decrease PCD (9.8 [8.5-11.9] vs. 8.8 [8.2-9.6] mm.mm-2, p = 0.08). Fifteen patients (50%) died within 30 days after admission. Patients who had low final PCD (≤ 10.3 mm.mm-2; 64%) were more likely to die than patients who had preserved PCD (>10.3 mm.mm(-2); mortality 72% vs. 17%, p = 0.003).

CONCLUSION

This study demonstrates the effects of commonly used inotropic agents on parameters of tissue perfusion in patients with cardiogenic shock. Despite hemodynamic optimization, tissue perfusion was not sufficiently restored in most patients. In these patients, mortality was high. Interventions directed at improving microcirculation may eventually help bridging the gap between improved hemodynamics and dismal patient outcome in cardiogenic shock.