Exploring hemodynamics: a review of current and emerging noninvasive monitoring techniques

Noninvasive and Minimally Invasive Cardiac Output Monitoring: A Nursing Perspective

For decades, nurses have monitored and titrated medications based on cardiac output. In the past, this was almost exclusively done through the use of an invasive pulmonary artery catheter. However, there are inherent patient risks to using a pulmonary artery catheter, and trends have shown a decreased use of this method. Advances in technology have brought about various noninvasive and minimally invasive methods to monitor cardiac output including pulse contour analysis, finger cuff technology, thoracic bioimpedance and bioreactance, and endotracheal electrical bioimpedance. A review of current noninvasive and minimally invasive methods to monitor cardiac output, and nursing considerations are discussed.

Ultrasound and Other Advanced Hemodynamic Monitoring Techniques in the Intensive Care Unit

The ideal device for hemodynamic monitoring of critically ill patients in the intensive care unit (ICU) or the operating room has not yet been developed. This would need to be affordable, consistent, have a very low margin of error (<30%), be minimally or noninvasive, and allow the clinician to make a reasonable therapeutic decision that consistently led to better outcomes. Such a device does not yet exist. This article will describe the distinct options we, as critical care physicians, currently possess for this Herculean endeavor.

CVP and echo Measurements are Associated with Improved Outcomes in Patients with Gastrointestinal (GI) Hemorrhage: A Retrospective Analysis of the MIMIC- IV Database

Purpose: Mortality associated with acute Gastrointestinal (GI) hemorrhage in intensive care units (ICU) has remained high in patients suffering from hemodynamic instability. Prompt recognition and rapid assessment of bleeding severity are crucial to improve survival. Central venous pressure (CVP) monitoring is commonly used for early recognition of intravascular imbalances, but its effectiveness in predicting fluid responsiveness is often questioned. Echocardiography (echo) is a rapid, noninvasive method to repeatedly assess cardiac function and fluid responsiveness. This study investigated the impact of CVP and echo measurements on the outcomes of critically ill patients with GI hemorrhage. Methods: The study was based on the Medical Information Mart for Intensive Care IV (MIMIC- IV) database. Patients were divided into four groups according to the usage of CVP and/or echo. The primary outcomes were 7-day, 14-day, 28-day, and overall mortalities after ICU admission. Cox Proportional-Hazards Models were used to elucidate the relationship between CVP/ Echo monitoring and mortality. The severity of illness of patients were adjusted by qSOFA score, SOFA score and base deficit level at admission. Results: Among 1705 eligible patients, 82 patients had both CVP and echo, 85 had CVP only, and 116 had Echo only. The results of survival analysis indicated that, comparing with those without either CVP or echo, the echo utilization was associated with improved mortalities at all time points during ICU stay for patients with moderate GI hemorrhage, and the combined use of CVP and echo was associated with lower 7-day,14-day and overall mortalities for patients with severe GI hemorrhage. Conclusion: Early usage of CVP and echo monitoring or echo alone are associated with lower mortality in the short and long-term when compared to patients without either measurement. Clinicians should consider goal-directed resuscitation guided by echo with/without CVP in patients with GI hemorrhage early after admission to ICU.

Utilization of Echocardiography After Acute Kidney Injury Was Associated with Improved Outcomes in Patients in Intensive Care Unit

Background

We aimed to investigate the association between usage of transthoracic echocardiography (TTE) within 24 hours after acute kidney injury (AKI) and the prognosis of patients in intensive care unit (ICU).

Methods

The Medical Information Mart for Intensive Care III (MIMIC-III) database was used to identify AKI patients with and without TTE administration. The primary outcome was 28-day mortality. Multivariable regression was used to clarify the association between TTE and clinical outcomes and propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were utilized to validate our findings.

Results

Among 23,945 eligible AKI patients, 3361 patients who received TTE and 3361 who did not conduct TTE had similar propensity scores which were included in this study. After matching, the TTE group had a significantly lower 28-day mortality (OR 0.80, 95% CI 0.72–0.88, P<0.001). Patients in the TTE group received more fluid on day 1 and day 2 and had a more urine volume on day 1 and day 3, and the reduction in serum creatinine was greater than that in the no TTE group. The mediating effect of creatinine reduction was remarkable for the whole cohort (P=0.02 for the average causal mediation effect).

Conclusion

TTE utilization was associated with decreased risk-adjusted 28-day mortality for AKI patients in ICU and was proportionally mediated through creatinine reduction.

Utilization of echocardiography during septic shock was associated with a decreased 28-day mortality: a propensity score-matched analysis of the MIMIC-III database

Background

Hemodynamic management is of paramount importance in patients with septic shock. Echocardiography has been increasingly used in assessing volume status and cardiac function. However, whether the utilization of echocardiography has an impact on prognosis is unknown. Thus, we intended to explore its effect on the outcomes of patients with septic shock.

Methods

The study was based on the Medical Information Mart for Intensive Care (MIMIC) III database. Septic shock patients were divided into two groups according to the usage of echocardiography during the onset of septic shock. The primary outcome was 28-day mortality. Secondary outcomes included the usage of inotropes, ventilation-free and norepinephrine-free time, and fluids input. Propensity-score matching was used to reduce the imbalance.

Results

Among 3,291 eligible patients, 1,289 patients who underwent echocardiography (Echo), and 1,289 who did not receive the Echo, had similar propensity scores and were included in the analyses. After matching, the Echo group had a significantly lower 28-day mortality (33.2% vs. 37.7%, P=0.019). More patients in the Echo group received pulmonary artery catheter (PAC) (4.2% vs. 0.2%, P<0.001) and inotropes (17.8% vs. 7.1%, P<0.001). In the survival analysis, Echo utilization was associated with improved 28-day mortality [hazard ratio (HR): 0.83; 95% confidence interval (CI), 0.73-0.95, P=0.005]. A reduced likelihood of 28-day mortality in patients with Echo vs. those without Echo was maintained either when excluding patients receiving multiple echocardiography scans (HR, 0.82; 95% CI, 0.72-0.94; P=0.004) or when excluding patients undergoing PAC or pulse index continuous cardiac output (PiCCO) (HR, 0.87; 95% CI, 0.76-0.99; P=0.034).

Conclusions

Utilization of echocardiography was associated with improved 28-day outcomes in patients with septic shock.

Stroke Volume Optimization: Utilization of the Newest Cardiac Vital Sign: Considerations in Recovery from Cardiac Surgery

The hemodynamic monitoring landscape is rapidly evolving from pressure-based and static parameters to more blood flow-based and dynamic parameters. Consensus guidelines for cardiac surgery state that the pulmonary artery catheter is neither required nor helpful in most patients. In the meantime, critical care has been searching for the alternatives to the pulmonary artery catheter and protocols for use. Best available evidence for any protocol developed suggests the inclusion of stroke volume optimization to determine fluid responsiveness. Additional strategies to using stroke volume to optimize hemodynamics, including case studies, are discussed.

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.