Is there still a place for the Swan-Ganz catheter? Yes

A new perspective on an old method: gated SPECT imaging for left ventricular contractile function assessment

The ejection fraction (LVEF) is a commonly used marker of left ventricular function. However, because it is strongly influenced by loading conditions, it can be inaccurate in representing cardiac contractility. We therefore evaluated a gated SPECT based tool to simultaneously assess preload, afterload, and contractility. Using gated SPECT-determined ventricular volumes and arterial tension measurements, we calculated ventricular and arterial elastance (Ev and Ea), as well as end-diastolic volumes, which are surrogates for contractility, afterload, and preload, respectively. We applied this protocol to 1462 consecutive patients and assessed the ventricular function in patients with and without myocardial infarction. The median LVEF was 68% (IQR 62-74%). Patients with infarction exhibited decreased contractility (ventricular elastance of 3 mmHg/ml vs. 6 mmHg/ml), compensated by an increase of preload (end-diastolic volume of 100 ml vs. 78 ml) and a decrease in afterload (arterial elastance of 1.8 mmHg/ml vs. 2.2 ml/mmHg). These interactions yielded a preserved ejection fraction in both groups. Gated SPECT-measured volumes were consistent with values reported in the literature. In addition, the combination of nuclear imaging and arterial tension measurement accounted for not only the ejection fraction but also the loading context, providing a more accurate representation of cardiac contractility.

Study of the accuracy of a radial arterial pressure waveform cardiac output measurement device after cardiac surgery

BACKGROUND

Less invasive monitoring, such as radial arterial pulse contour analysis (ProAQT® sensor), represents an alternative when hemodynamic monitoring is necessary to guide postoperative management and invasive monitoring is not technically feasible. The aim of the study is to evaluate the accuracy of the ProAQT® sensor cardiac output measurements in comparison with Pulmonary Artery Catheter (PAC) during the postoperative course of patients who underwent cardiac surgery with cardiopulmonary bypass.

CASE PRESENTATION

Prospective observational study in a Surgical Intensive Care Unit of a tertiary university hospital. Ten patients with a mean age of 73.5 years were included. The main comorbidities were hypertension, diabetes, dyslipidemia and the preoperative left ejection fraction was 43.8 ± 14.5%. Regarding the type of surgery, six patients underwent valve surgery, two underwent coronary artery bypass grafting and two underwent aortic surgery. The cardiac index measured simultaneously by the ProAQT® sensor was compared with the PAC. The parameters were evaluated at predefined time points during the early postoperative courses (6 h, 12 h, 24 h, 48 h and 72 h). The degree of agreement with the cardiac index between the PAC and the ProAQT® sensor along the time points was measured using the concordance correlation coefficient, Bland-Altman analysis, and four-quadrant plot. Sixty-three pairs of measurements were analyzed. We showed that measurements of cardiac index were slightly higher with PAC (β ̂ = - 0.146, p-value = 0.094). The concordance correlation coefficient for the additive model of cardiac index was 0.64 (95% Confidence Interval: 0.36, 0.82), indicating a high concordance between both sensors. Bland-Altmann analysis showed a mean bias of 0.45 L·min^-1·m^-2, limits of agreement from - 1.65 to 2.3 L·min^-1·m^-2, and percentage of error was 82.5%. Four-quadrant plot of changes in cardiac index showed a good concordance rate (75%), which increases after applying the exclusion zone (87%).

CONCLUSIONS

In patients undergoing cardiac surgery, the ProAQT® sensor may be useful to monitor cardiac index during the postoperative period, especially when more invasive monitoring is not possible.

Continuous cardiac output measured with a Swan-Ganz catheter reacts too slowly in animal experiments with sudden circulatory failure

Background

In many animal experiments, it is vital to detect sudden changes in cardiac output (CO). This porcine study compared CO that was measured with a Swan‐Ganz pulmonary catheter with the gold standard (which was a transit‐time flow probe around the pulmonary artery) during interventions that caused hemodynamic instability.

Methods

In one series, 7 pigs were exposed to sudden changes in CO. In another series, 9 pigs experienced more prolonged changes in CO. All the pigs had a Swan‐Ganz catheter placed into the pulmonary artery and a flow probe around the pulmonary artery. Adrenaline infusion and controlled hemorrhage were used to increase and decrease CO, respectively. The measurements of CO before and after each intervention were compared for correlation, agreement, and the time delay that it took each method to detect at least a 30% change in CO. A Bland–Altman test was used to identify correlations and agreements between the methods.

Results

In the first series, there was a delay of 5–7 min for the Swan Ganz catheter to register a 30% change in cardiac output, compared with the flow probe. However, during prolonged changes in CO in the second series, there was a good correlation between the 2 methods. Mixed venous oxygen saturation reacted faster to changes than did CO; both were measured via the Swan‐Ganz catheter.

Conclusions

In many animal studies, the use of Swan‐Ganz catheters is suitable; however, in experiments with sudden hemodynamic instability, the flow probe is the most advantageous method for measuring CO.

The Pulmonary Artery Catheter in the Perioperative Setting: Should It Still Be Used?

The pulmonary artery catheter (PAC) was introduced into clinical practice in the 1970s and was initially used to monitor patients with acute myocardial infarctions. The indications for using the PAC quickly expanded to critically ill patients in the intensive care unit as well as in the perioperative setting in patients undergoing major cardiac and noncardiac surgery. The utilization of the PAC is surrounded by multiple controversies, with literature claiming its benefits in the perioperative setting, and other publications showing no benefit. The right interpretation of the hemodynamic parameters measured by the PAC and its clinical implications are of the utmost essence in order to guide a specific therapy. Even though clinical trials have not shown a reduction in mortality with the use of the PAC, it still remains a valuable tool in a wide variety of clinical settings. In general, the right selection of the patient population (high-risk patients with or without hemodynamic instability undergoing high-risk procedures) as well as the right clinical setting (centers with experience and expertise) are essential in order for the patient to benefit most from PAC use.

Agreement between continuous and intermittent pulmonary artery thermodilution for cardiac output measurement in perioperative and intensive care medicine: a systematic review and meta-analysis

BACKGROUND

Pulmonary artery thermodilution is the clinical reference method for cardiac output monitoring. Because both continuous and intermittent pulmonary artery thermodilution are used in clinical practice it is important to know whether cardiac output measurements by the two methods are clinically interchangeable.

METHODS

We performed a systematic review and meta-analysis of clinical studies comparing cardiac output measurements assessed using continuous and intermittent pulmonary artery thermodilution in adult surgical and critically ill patients. 54 studies with 1522 patients were included in the analysis.

RESULTS

The heterogeneity across the studies was high. The overall random effects model-derived pooled estimate of the mean of the differences was 0.08 (95%-confidence interval 0.01 to 0.16) L/min with pooled 95%-limits of agreement of - 1.68 to 1.85 L/min and a pooled percentage error of 29.7 (95%-confidence interval 20.5 to 38.9)%.

CONCLUSION

The heterogeneity across clinical studies comparing continuous and intermittent pulmonary artery thermodilution in adult surgical and critically ill patients is high. The overall trueness/accuracy of continuous pulmonary artery thermodilution in comparison with intermittent pulmonary artery thermodilution is good (indicated by a pooled mean of the differences < 0.1 L/min). Pooled 95%-limits of agreement of - 1.68 to 1.85 L/min and a pooled percentage error of 29.7% suggest that continuous pulmonary artery thermodilution barely passes interchangeability criteria with intermittent pulmonary artery thermodilution. PROSPERO registration number CRD42020159730.

CON: Pulmonary artery catheter use should be forgone in modern clinical practice

The pulmonary artery catheter (PAC) and its role in the practice of modern medicine remains to be questioned and has experienced a substantial decline in its use in the most recent decades. The complications associated to its use, the lack of consistency of the interpretation provided by the PAC among clinicians, the development of new hemodynamic methods, and the deleterious cost profile associated to the PAC are some of the reasons behind the decrease in its use. Since its introduction into clinical practice, the PAC and the data obtained from its use became paramount in the management of critically ill patients as well as for the high-risk/invasive procedures. Initially, many clinicians were under the impression that regardless the clinical setting, acquiring the information provided by the PAC justified its use, until a growing body of evidence demonstrated its lack of mortality and morbidity improvement, as well as several reports of the presence of difficulties—some of them fatal—during its insertion. The authors present an updated review discussing the futility of the PAC in current clinical practice, the complications associated to its insertion, the lack of mortality benefit in critically ill patients and cardiac surgery, as well as present alternative hemodynamic methods to the PAC.

PRO: The pulmonary artery catheter has a paramount role in current clinical practice

Ever since its clinical introduction, the utilization of the pulmonary artery catheter (PAC) has been surrounded by multiple controversies, mostly related to imprecise clinical indications and the complications derived from its placement. Currently, one of the most important criticisms of the PAC is the ambiguity in the interpretation of its hemodynamic measurements and therefore, in the translation of this data into specific therapeutic interventions. The popularity of the PAC stems from the fact that it provides hemodynamic data that cannot be obtained from clinical examination. The assumption is that this information would allow better understanding of the individual's hemodynamic profile which would trigger therapeutic interventions that improve patient outcomes. Nevertheless, even with the current diversity of hemodynamic devices available, the PAC remains a valuable tool in a wide variety of clinical settings. The authors present a review exposing the benefits of the PAC, current clinical recommendations for its use, mortality and survival profile, its role in goal-directed therapy, and other applications of the PAC beyond cardiac surgery and the intensive care unit.

Mixed Shock States: A Case for the Pulmonary Artery Catheter

The pulmonary artery catheter is a valuable tool available to the clinician for use in deciphering complex hemodynamic scenarios. Patients in shock, particularly those who are elderly or have premorbid conditions such as heart failure, may have atypical presentations. Additional hemodynamic data may help identify interventions that might seem counterintuitive, such as the use of vasoconstrictors in patients with low cardiac output. Interpretation of pulmonary artery hemodynamic data is a skill that should not be relegated to the past. This article reviews the use of a pulmonary artery catheter in mixed shock states. A case study is used to demonstrate how pulmonary artery catheter hemodynamic values can guide the care of these patients.

This is your toolkit in hemodynamic monitoring

PURPOSE OF REVIEW

To appraise the basic and more advanced methods available for hemodynamic monitoring, and describe the definitions and criteria for the use of hemodynamic variables.

RECENT FINDINGS

The hemodynamic assessment in critically ill patients suspected of circulatory shock follows a step-by-step algorithm to help determine diagnosis and prognosis. Determination of accurate diagnosis and prognosis in turn is crucial for clinical decision-making. Basic monitoring involving clinical examination in combination with hemodynamic variables obtained with an arterial catheter and a central venous catheter may be sufficient for the majority of patients with circulatory shock. In case of uncertainty of the underlying cause or to guide treatment in severe shock may require additional advanced hemodynamic technologies, and each is utilized for different indications and has specific limitations. Future developments include refining the clinical examination and performing studies that demonstrate better patient outcomes by targeting hemodynamic variables using advanced hemodynamic monitoring.

SUMMARY

Determination of accurate diagnosis and prognosis for patients suspected of circulatory shock is essential for optimal decision-making. Numerous techniques are available, and each has its specific indications and value.