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Editorials: Editorial

Blood Pressure Monitoring in Obese Patients: What Is the Size of the Problem?

Joosten, Alexandre MD*; Rinehart, Joseph MD; Cannesson, Maxime MD, PhD

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doi: 10.1213/ANE.0000000000003880
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Obesity rates continue to rise in industrialized countries, and obesity is becoming a major public health problem, in no small part due to associated comorbidities (mainly respiratory and cardiovascular) and associated mortality, which could represent up to a 22% decreased life expectancy in men.1 An increased prevalence of obesity leads directly to an increased frequency of management of obese patients in the perioperative setting. Every anesthesiologist knows that perioperative care of obese patients brings unique challenges—potentially difficult airway management and intubation, increased risk of hypoxia and desaturation during anesthesia induction, difficulty with intravenous placement and procedures in general, and obstructive sleep apnea and atelectasis in the postoperative period.

Obesity is frequently associated with cardiac comorbidities, such as hypertension, heart failure, and coronary vessel disease, as well as diseases like diabetes that may further increase cardiovascular risks, making accurate monitoring arguably all the more important than the general population.2 Monitoring obese patients, however, particularly when blood pressure measurement may be concerned, is not easy. Indeed, which anesthesiologist has never encountered difficulties obtaining a reliable blood pressure measurement with the standard upper arm cuff? The upper arm cuffs may pop off, the Velcro fastener suddenly released. The cuff may cycle endlessly with the notice: “measurement too long.” The cuff may continue to slide off a conical upper arm toward the elbow, so the forearm or even around the leg is tried in desperation after multiple negative attempts on the arms. All of these scenarios happen routinely to all medical personnel taking care of obese patients, and the challenge increases with the degree of obesity.

With a growing incidence of obesity worldwide, the described situation may become more and more common in the years to come. The problem is not trivial—inaccurate blood pressure measurement can lead to improper treatment of hypo- or hypertension and associated side effects. Granted, if an oscillometric upper arm cuff does not fit or simply will not read, clinicians may insert an arterial catheter. Placement will be challenging, however, as it involves the same difficulties as placement of a peripheral intravenous line in the obese patient. In addition, the risk associated with the surgery may not justify the risk of an arterial line placement, especially for interventions with minimal anticipated fluid shifts or blood loss, as would typically be the case for laparoscopic bariatric surgery.

In this issue of Anesthesia & Analgesia, we highlight 2 articles that focus on the problem of blood pressure measurement in the obese patient. In the first article, Eley et al3 provide an excellent up-to-date and focused narrative review on “Perioperative Blood Pressure Monitoring in Patients With Obesity.” In this review, the authors “discuss the relevance of hypertension management in the care of obese patients, the currently available methods for perioperative monitoring of blood pressure, and they explore the opportunities that exist to improve care in obese patients undergoing surgical procedures. They also focus on the problem of measuring blood pressure with a review of the importance of arm-cuff size and the different continuous and noninvasive alternatives to the traditional upper arm cuff, highlighting their advantages, limitations, and potential role in the perioperative care of obese patients.” In the second article, Rogge et al4 assess and compare continuous arterial pressure measurements with noninvasive finger cuff technology (Clearsight System; Edwards Lifesciences, Irvine, CA) to invasive arterial pressure measurements, the reference method, in 35 morbidly obese patients during laparoscopic bariatric surgery. They demonstrate that arterial pressure monitoring with the finger cuff technology showed good accuracy, precision, and trending capabilities for mean arterial pressure. Based on an error grid analysis (a statistical test recently proposed for blood pressure method comparison studies by Saugel et al5), they further show that >99% of Clearsight-derived arterial pressure measurements were categorized in no- or low-risk disagreement zones, meaning that monitoring of arterial pressure with this continuous and noninvasive technology did not result in any clinical risk for the patient compared to monitoring with an arterial line. The same team previously showed similar results using a different continuous noninvasive blood pressure monitoring system (CNAP; CNSystems Medizintechnik AG, Graz, Austria) in a study published in Anesthesia & Analgesia.6 Because these systems are relatively easy to attach around the fingers of even obese patients, these technologies could be an interesting option for arterial pressure monitoring in morbidly obese patients undergoing surgery (Figure).

Figure.
Figure.:
Obese patient with an upper XL arm cuff and the Clearsight system (Edwards Lifesciences, Irvine, CA). XL indicates extra large.

With a better understanding of the challenges and limits of blood pressure monitoring in the obese population during the perioperative period, the next major challenge for clinicians and researchers will be to determine whether the increased perioperative risk these patients face can be reduced with tighter management or other targeted therapies. To date, for example, continuous monitoring has not demonstrated a beneficial impact on patient outcome.7 Gains have been made in postoperative respiratory complications in the obese through the use of appropriate respiratory management,8,9 reduction of narcotic administration through multimodal pain management approaches,10–12 and early identification and management of patients at risk of obstructive sleep apnea.13 Whether such gains can be made for cardiovascular outcomes remains to be seen. Despite this, continuous noninvasive blood pressure monitoring has been shown to decrease by half the amount of intraoperative hypotensive episodes.14 Therefore, it can be seen as an appealing strategy for detecting intraoperative “hypotensive phases” earlier than intermittent upper arm cuff and, as a result, may improve patient safety.

The obesity epidemic is not likely to end soon. On the contrary, the upper limits for safety in bariatric surgery are still being explored, with recent studies suggesting even super-obese and super-super-obese patients may be considered reasonably safe candidates for bariatric procedures.15,16 We must, therefore, continue to advance our own comfort and understanding of the unique challenges in this population and seek ways to mitigate the risks and optimize patient outcome; that is, to do what we, as anesthesiologists, have always done.

DISCLOSURES

Name: Alexandre Joosten, MD.

Contribution: This author helped draft the manuscript.

Conflicts of Interest: A. Joosten is a consultant for Edwards Lifesciences (Irvine, CA).

Name: Joseph Rinehart, MD.

Contribution: This author helped draft the manuscript.

Conflicts of Interest: J. Rinehart has ownership interest in Sironis, a company developing closed-loop systems, and he is a consultant for Edwards Lifesciences (Irvine, CA).

Name: Maxime Cannesson, MD, PhD.

Contribution: This author helped draft the manuscript.

Conflicts of Interest: M. Cannesson has ownership interest in Sironis, a company developing closed-loop systems, and he is a consultant for Edwards Lifesciences (Irvine, CA).

This manuscript was handled by: Jean-Francois Pittet, MD.

REFERENCES

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