Edwards Acumen hypotension predictive index software.

Edwards Acumen hypotension predictive index software.

“In the last decade, there has been renewed interest in predicting, real-time intervention, and optimization of hemodynamics in the OR and ICU setting for anesthesia and postoperative care,” said Kurosh Takhtehchian, DO, Associate Clinical Professor of Anesthesiology at University of Illinois Health at Chicago. Though hemodynamic monitoring has been a part of intraoperative management for some time, Dr. Takhtehchian worked on a project analyzing the utlility of the Edwards Acumen IQ monitor. Dr. Takhtehchian remarked that this technology primes anesthesiologists to facilitate rapid patient recovery with fewer complications.

Intraoperative management has been a mainstay since anesthesiologists monitored urine output, analyzed blood gas results from sampling in the OR to see if a patient required more fluids, followed blood pressure parameters, and looked at overall hemodynamics. In recent decades, companies have emerged with technology such as pulmonary artery catheters, which have become commonly used for cardiac surgery and complex cases to monitor volume status, the preload volume status, and septic or cardiogenic shock. Dr. Takhtehchian said, “Companies thereafter realized that as medicine evolved, and surgical techniques became less invasive, so too is monitoring of the anesthetic in patients. We have changed from total open abdominal surgeries to laparoscopic to robotic laparoscopic. The same advancements have happened for anesthesiology and the ICU in the management and assessment of patients.”

Medical products on the market today can measure a patient’s hemodynamics, such as blood pressure, volume status, and volume responsiveness. “Now, we can intervene in real time with parameters and numbers and evaluate changes of hemodynamics. Therefore, overall patient care can be more optimally managed – not by guesswork, but by reproducible and evidence-based data that minimizes complications such as low blood pressure events, acute kidney injury, cardiac dysfunction or stress ischemia to the heart, and fluid overload causing postoperative edema,” Dr. Takhtehchian said. “More patients will have improved outcomes intraoperatively with fewer postoperative requirements for an ICU stay because of the positive interventions on the hemodynamics parameters and overall volume status.”

The available technology is widely varied and offers monitoring solutions before, during, and after treatments or surgical procedures. The Edwards Acumen IQ Sensor – one of the most widely used – offers software such as a hypotension predictive index that provides information regarding the likelihood of a patient experiencing a hypotensive event. The product suite offers a finger-based cuff that delivers continuous blood pressure monitoring and advanced hemodynamic parameters noninvasively. It utilizes sensors that update automatically to reflect rapid physiological changes and provide insight into the root cause of hypotension for surgical and nonsurgical patients. It also uses tissue oximetry sensors that are tailored to accommodate patient differences.

“The new technology optimizes hemodynamics with minimally invasive and noninvasive measurements, allowing the anesthesiologist to make real-time evaluations,” Dr. Takhtehchian explained. This offers definitive calculations on necessities such as giving more volume if blood pressure or urine output is low, or adding a vasopressor to give more squeeze when vasoplegia or vasodilation is present, he added. “Without the monitoring technology, the probability of volume overload is higher, and the resultant pulmonary and bowel edema can place the patient at risk for a longer ICU stay and even the need for a ventilator. Additionally, patients are known to exhibit a slower recovery of their bowel function or suffer under-resuscitation intraoperatively with low blood pressure readings throughout the procedure, causing hypoperfusion injury to vital organs such as the kidneys, cardiac, and mesentery system.”

Hemodynamic monitors aid anesthesiologists in efficiently and effectively intervening to save these vital organs and to minimize complications, Dr. Takhtehchian said. “With this technology, we get more calculated responsiveness directly through the arterial line that lets you know how to intervene. Data on cardiac index and cardiac output allows you to affect the patient’s overall perfusion, forward flow, and blood flow. Other parameters such as the hypotension predictive index on the Edwards Acumen IQ sensor allow anesthesiologists to be alerted to a low blood pressure event before it happens by monitoring a trending slow-down that may not be otherwise noticed.”

A study by Pinksy et al. found that in acute care settings, goal-directed therapy linked to monitoring decreased perioperative complications and length of stay in high-risk surgery patients (Crit Care 2006;26:294). Patient-specific personalized resuscitation approaches, including dynamic measures to define volume responsiveness and vasomotor tone and limiting fluid administration and vasopressor duration, reduced length of care, according to the study.

In a separate study of 596 patients, Lima et al. found that the use of hemodynamic and depth of anesthesia (DOA) monitoring was associated with a significant improvement in postoperative outcome (Journal of Clinical Monitoring and Computing 2019; 33:365-71). The use of cardiac output, central venous oxygen saturation, and DOA monitoring increased, while intraoperative fluid volumes decreased, per the study. Additionally, postoperative delirium, urinary tract infections, and median hospital length of stay decreased with the use of monitoring, Lima et al. found. In patients undergoing major open abdominal surgery for cancer, despite an increase in surgical risk, the implementation of hemodynamic and DOA monitoring improved patient outcomes, the study reported.

In his own patient care as an anesthesiologist and in the intensive care setting, Dr. Takhtehchian has seen hemodynamic monitoring technology improve the judicious overuse of fluids in patients undergoing a variety of surgical interventions. “Technologies such as the Acumen sensor, and similar products such as the PiCCO technology, minimize the amount of time patients are hypotensive intraoperatively and minimizes fluid overload and fluid resuscitation. This leads to fewer end-organ injuries, such as acute myocardial or kidney injury.”

Dr. Takhtehchian has seen the technology used in surgical cases where there is limited ability to evaluate hemodynamics intraoperatively, such as emergency cases where cardiac imaging is not available. “Intraoperatively, this is my way of evaluating intravascular responsiveness and it allows me to judge when patients require boluses, fluid restriction, and other hemodynamic additions by medication,” he shared.

With these goal-directed algorithms, clinicians can follow a more structured volume evaluation with fewer variable outcomes, Dr. Takhtehchian said. “If you can remove the variables, providers can make more scientific and algorithmic decisions that are proven to have widespread positive effects. It allows the reduction of clinician guesswork and the use of clinical parameters that are free from user bias or misinterpretation. The tools provide added confidence to decision-making, allowing better judgment and goal-directed therapies.”

Fewer variable outcomes and a lowered risk for patient injury could also reduce hospital costs, Dr. Takhtehchian added. “If we can reduce the hospital’s utilization of dialysis and ventilators and reduce ICU stays, we will save time and money while improving the reputation of the hospital by remaining at the forefront of technology with the most widely accepted minimally and noninvasive monitors.”