|Year : 2019 | Volume
| Issue : 2 | Page : 54-56
Hemodynamic early goal-directed therapy: Explaining the fine print
Zoe Goldthwaite1, Michael S Firstenberg1, Alex Botsch2
1 Department of Cardiothoracic and Vascular Surgery, The Medical Center of Aurora, Aurora, CO, USA
2 Department of Critical Care Medicine, Summa Akron City Hospital, Akron, OH, USA
|Date of Web Publication||26-Jun-2019|
Dr. Michael S Firstenberg
The Medical Center of Aurora, 1444 S. Potomac Street, Suite 200, Aurora, CO 80012
Source of Support: None, Conflict of Interest: None
| Abstract|| |
The management of patients after cardiothoracic surgery can be very complex. Variabilities exist in hemodynamic status after cardiac surgery and the use of cardiopulmonary bypass – all of which can have a significant impact on myocardial Frank–Starling curves. Typically, invasive monitoring with pulmonary artery catheters is used to assess the complex physiology that these patients experience in the perioperative setting. However, the use of invasive monitoring is not without risk, and the broader benefits are poorly defined. Furthermore, there is growing evidence to support the use of hemodynamic early goal-directed therapy to optimize outcomes in critically ill patients. The purpose of this editorial statement is the review of some of the current literature with regards to the utility of goal-directed therapy as applied to the postoperative cardiac surgical patient.
Keywords: Cardiac surgery, enhanced recovery, goal-directed therapy, pulmonary artery catheter
|How to cite this article:|
Goldthwaite Z, Firstenberg MS, Botsch A. Hemodynamic early goal-directed therapy: Explaining the fine print. Int J Crit Illn Inj Sci 2019;9:54-6
|How to cite this URL:|
Goldthwaite Z, Firstenberg MS, Botsch A. Hemodynamic early goal-directed therapy: Explaining the fine print. Int J Crit Illn Inj Sci [serial online] 2019 [cited 2020 Apr 2];9:54-6. Available from: http://www.ijciis.org/text.asp?2019/9/2/54/261457
| Introduction|| |
Improving outcomes for cardiothoracic surgery (CTS) patients are persistently under the microscope of surgeons and other providers caring for this population. New devices, new metrics, and innovative use for common laboratory tests are utilized to be the morbidity and mortality hero in perioperative care. Since 1995, improving outcomes such as length of stay (LOS), morbidity, and mortality have been addressed in the CTS population through the utilization of hemodynamic early goal-directed therapy (HEGDT). The literature overwhelmingly supports HEGDT, which is endorsed as a Class 1B recommendation with moderate-quality evidence from randomized controlled trials (RCTs) by the Enhanced Recovery After Surgery (ERAS®) Cardiac Surgery Society. Much like sepsis, HEGDT is implemented to improve outcomes for cardiac surgery patients by targeting hemodynamic endpoints the perioperative and immediate postoperative periods. Which HEGDT metrics to target, as well as the method of obtaining those targets, remain topics of debate and new technologies are challenging the gold standard pulmonary artery catheter (PAC) with compelling results. This manuscript will further discuss the utility of HEGDT and identify concerns of obtaining appropriate metrics with methods that deviate from the current standard as suggested by the latest literature. The methodology of the literature search included a comprehensive Google Scholar (https://scholar.google.com) and PubMed (https://www.ncbi.nlm.nih.gov/pmc/) for relevant review articles, high-quality case series, randomized and nonrandomized prospective and retrospective studies that focused on the keyword topics of HGDT, ERAS, PAC, and cardiac surgery. Pertinent references – specifically the titles and abstracts identified by the first and last authors (ZG and AB) – were reviewed for appropriateness by a senior board-certified cardiothoracic surgeon (MF).
| The Headlines|| |
It is well documented that the timely application of evidence-based medical and surgical protocols designed to optimize dynamic and flow-based hemodynamic parameters have been shown to be effective at improving patient costs and outcomes. Advanced hemodynamic monitoring allows continuous evaluation of changes in cardiovascular dynamics to guide clinical decision-making in patients at risk of hemodynamic instability in perioperative and intensive care medicine. The fluid management in CTS is a key component of care as fluid shifts and hypovolemia are likely to occur in the intraoperative and early postoperative phase.
Data suggest HEDGT can prevent organ dysfunction by identifying factors contributing most to hemodynamic disturbances and rapidly correct imbalances between oxygen consumption and delivery. The success of HEGDT is based on an early trial for intensive monitoring and aggressive management of circulatory parameters in patients with severe sepsis and septic shock. The trial's 6-h resuscitation protocol for guiding the administration of fluids and vasoactive agents markedly reduced hospital mortality prompting early, goal-directed therapy studies to be published worldwide and become a major component of the Surviving Sepsis Campaign guidelines. Despite these initial favorable outcomes, morbidity and mortality statistics in sepsis are unchanged overall since 2001 suggested by recent RCTs, the ProCESS, ARISE, and ProMISe trials,, – indicating the need for further improve sepsis care globally and thus questioning rigorous goal-directed therapy algorithms.
While CTS patients are not septic, they are subject to a systemic inflammatory response that can often lead to multiple organ failure and share many clinical manifestations associated with sepsis. Roles of HEGDT and hemodynamic variables in cardiac surgery have not been investigated to the same extent however, due to the array of considerable risks and complications with CTS patients. A recent meta-analysis demonstrated the significance of perioperative goal-directed hemodynamic approach in preventing postoperative complications in patients following cardiac surgery. Patients in goal-directed hemodynamic therapy were associated with a significantly shorter hospital stay compared to those in the control group. Similarly, Kapoor et al. observed a significant decrease in total duration of hospital and intensive care unit stay and decreased the duration of inotropic support with the use of HEGDT for hemodynamic management in high-risk patients undergoing an off-pump coronary artery bypass procedure. These findings emphasize the importance of HEGDT in helping to detect abnormal hemodynamic parameters early so corrections can be made to maintain cardiovascular variables within normal limits and improve patient outcomes. Further studies with a more focused inclusion criteria are recommended to continue assessing the benefit of HEGDT and validate findings to the wider CTS population.
| The Fine Print|| |
No isolated metric target is correlated with improved outcomes in CTS patients. However, it can be inferred with near certainty that a single metric alone is far too simplistic for such complex physiology as seen in the CTS population, particularly in the perioperative and early postoperative periods. In order to successfully achieve the benefits of HEGDT as outlined above, proper metrics and modalities for obtaining those metrics must be explored further.
| Proper Metrics|| |
Multiple studies employ a variety of hemodynamic metrics to target the optimal benefit of goal-directed therapy. A recent meta-analysis by Aya et al. identified five manuscripts total which studied HEGDT in CTS. The statistically significant commonalities between all five studies included in this meta-analysis are the reduction of postoperative complications and hospital LOS. However, each study was unique in which modalities were measured, and only three of the studies targeted one similar metric, that being mean arterial pressure (MAP).
Despite this similarity between studies, it should be noted that the MAP targets were different in all 3 (60–100 vs. 90–105 vs. 70). The other two studies were older (1995 and 2000) and shared one common metric between one other study each included in the meta-analysis (central venous pressure and ScvO2, respectively). Other metrics have been tested in the literature, but the best combination of targeted hemodynamic parameters for improving outcomes in CTS patients has yet to be identified. Perhaps, the association of HEGDT to improved outcomes is associated more with closer advanced hemodynamic monitoring and less about targeting the appropriate parameters; in other words, are clinicians simply paying better attention to detail in these studies?
| Proper Modalities|| |
Less invasive monitoring techniques have been heavily researched and published in the literature challenging the current gold-standard PAC. No single modality or device will be mentioned in this manuscript; but instead, limitations will be discussed regarding less- and non-invasive hemodynamic monitoring techniques in reference to their utility in CTS.
It is important to identify that the PAC also carries risks and limitations, but this data is conflicting. Multiple studies have suggested poor outcomes associated with PAC, while others refute these claims and suggest no difference between PAC and non-PAC groups undergoing cardiac surgery. However, a recent retrospective, cohort study suggests no difference in mortality between cardiac surgery patients who utilized the PAC and those who did not while identifying statistically significant decreased LOS and cardiopulmonary morbidity.
Advantages and disadvantages of hemodynamic monitoring modalities are well outlined including the PAC, less-invasive methods, and noninvasive methods. Less-invasive techniques, particularly those which rely on pulse contour variation and pulse pressure variation, are well studied and suggested for use in CTS.,, Interestingly, targeted parameters in these particular studies are higher than normal CI (2.5 vs. 2.0) and no cardiac index monitoring in the control group, introducing bias.,
However, these modalities fall victim to inaccuracy in a variety of settings including arrhythmias or extreme bradycardia, spontaneous breathing or mechanical ventilation with low tidal volumes, open thorax, and the presence of intra-aortic balloon pump, all of which are present in cardiac surgery., In the early postoperative period after CABG, atrial fibrillation is reported from 15% to 40% of patients, and as high as 60% in those who also undergo concomitant valve surgery. In most cases, spontaneous breathing with the intent of extubation occurs within 6 h of surgery, providing another challenge for less-invasive monitoring modalities. Finally, perioperative utility of less-invasive modalities is also challenging due to open thorax.
Despite conflicting data and support for less-invasive monitoring, the PAC is still widely used in CTS and is still viewed as the standard for hemodynamic monitoring in CTS and has even demonstrated a trend toward increased use over the last decade. This is likely due to lack of alternative, superior modalities that compare to the PAC in cardiac surgery, therefore outweighing the risks of its use.
| Conclusion|| |
The substantial heterogeneity across recent literature on HEGDT in CTS patients are likely due to considerable variations in therapeutic goals, fluid regimes, hemodynamic parameters, and monitoring devices employed. Several concerns arise regarding the process and medium utilized to implement HEGDT. The lack of uniformity across studies raises questions as to which targeted hemodynamic metrics should be followed and if higher “normal” targets should be considered in the CTS population. In addition, the utilization of noninvasive hemodynamic monitoring devices, which have not consistently outperformed the gold-standard PA catheter, should be used with caution as their accuracy is often compromised in this population. Furthermore, studies supporting the use of HEGDT and non- or minimally-invasive device use implement bias into the variable group, leading to further concerns surrounding the results and credibility of these studies. Despite many seemingly promising benefits of HEGDT; definitive, unbiased conclusions on its benefit cannot be made until further analyses evaluating the role of perioperative hemodynamic optimization are warranted.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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