Article Text

Case series
Comparison of a pressure-sensing sheath and radial arterial line for intraoperative blood pressure monitoring in neurointerventional procedures
1. Michael T Froehler,
2. Rohan Chitale,
3. Jordan A Magarik,
4. Matthew R Fusco
1. Cerebrovascular Program, Vanderbilt University Medical Center, Nashville, Tennessee, USA
1. Correspondence to Dr Michael T Froehler, Cerebrovascular Program, Vanderbilt University, Nashville, TN 37232, USA; m.froehler{at}vanderbilt.edu

## Abstract

Purpose The efficiency of neuroendovascular procedures may partly depend on the time devoted to placement of a radial arterial line (RAL) for intraoperative blood pressure monitoring. An alternative approach is to use a pressure-sensing sheath (PSS) that serves to provide invasive blood pressure monitoring without requiring a separate procedure for placement. We compared the use of a RAL versus PSS and assessed procedure time, anesthetist and patient satisfaction, and cost.

Methods We performed a single-center, prospective, blockwise, comparative trial of procedure start time using traditional RAL placement versus the EndoPhys PSS for invasive blood pressure monitoring. Endpoints included time from room arrival to groin puncture, patient and anesthetist satisfaction ratings, and costs associated with RAL placement.

## Discussion

This study has shown that the use of a PSS for intraoperative blood pressure monitoring was faster than RAL placement by an average of over 10 min. The output of the PSS was generally reliable and resulted in less patient discomfort compared with placement of a RAL.

Increasing efficiency in the operating room is a common goal.14–16 In particular, increased throughput can optimize the number of procedures performed daily, improve financial performance of the room, improve physician efficiency, and improve patient satisfaction and outcomes by reducing the length of time patients spend under general anesthesia. Our study shows that the use of a PSS instead of a RAL may result in an average time saving of over 10 min. In addition, we found that the time to place the RAL was variable, with an IQR of 13.75 min. In fact, several patients with RAL placement had delays to procedure start of over 80 min, whereas none of the PSS-alone group had such long delays.

Certain types of procedures are particularly time-critical. In particular, efficiency is critical in the endovascular treatment of acute ischemic stroke.17 18 In this study, we only included patients undergoing elective procedures. However, the time savings demonstrated here could be applied to emergent procedures such as thrombectomy for stroke. In fact, given the need for swift treatment, many proceduralists forgo the placement of a RAL before thrombectomy and instead simply rely on blood pressure measurement via a cuff. However, given the critical importance of blood pressure and hemodynamic management in patients with acute ischemic stroke, real-time invasive blood pressure monitoring using a PSS would be helpful. Fortunately, an 8-Fr PSS has recently become available, however, its impact on emergent thrombectomy procedures has not yet been evaluated.

If RAL placement is part of the normal routine for acute stroke treatment, a time saving of over 10 min could be expected to result in improved functional outcomes.17 19 20 But more importantly, the variability of the time required for RAL placement suggests that some stroke procedures could be delayed by over 80 min. This would certainly be expected to impact the rate of good functional outcome, potentially reducing the rate of good functional outcome by 7% to 30%.17 21

The impact on patient pain and satisfaction should not be overlooked. Many studies have shown that pain is strongly linked to patient dissatisfaction.22–24 In this context, one should first examine whether continuous, invasive blood pressure monitoring is necessary. If so, as it often is with complex intracranial cerebrovascular procedures, the use of a PSS may still provide the necessary physiological monitoring while avoiding patient discomfort. In this study, we found that 6/19 patients reported bothersome pain. Furthermore, the mean reported score for maximum pain actually increased from postoperative day 1 to outpatient follow-up at 1 month. This suggests that patients do not forget pain associated with their procedure, and thus their pain is likely to affect long-term satisfaction.

Anesthetist satisfaction is also important. Given the critical nature of hemodynamic factors during cerebrovascular procedures, an accurate and reliable blood pressure measurement is mandatory. A previous study has already shown the similarity between RAL and PSS blood pressure measurement.10 The current study showed that, in general, anesthetists were satisfied with either the RAL or PSS. Discrepancies were noted in 17.5% of procedures, and these differences were felt to be due to regional pressure differences attributable to atherosclerotic stenotic disease. Perhaps more important than absolute value of blood pressure measurement is the detection of change, which was consistently reliable with both the RAL and PSS throughout this study. This may partly explain the high anesthetist satisfaction scores associated with use of the PSS.

Our financial analysis showed that the cost of RAL placement is not insignificant. Particularly in light of the time disadvantage associated with RAL placement, the use of the PSS may be justified in many situations. However, the precise estimate of operating room opportunity cost is highly variable and depends on many factors that may be unique to the institution. Furthermore, the cost of the equipment itself will vary greatly from institution to institution. With these limitations and our small sample size, a true cost-effectiveness analysis is far beyond the scope of this article. Nonetheless, the results here do provide a framework for individual institutions to perform their own cost analyses for approaches to intraoperative blood pressure monitoring during neuroendovascular procedures.

This study has limitations. While we have shown that additional time was necessary for RAL placement prior to procedure start, there may be idiosyncratic reasons for this such as placement of RAL in the OR rather than in the holding room. It was also an unblinded study, which could have had some effect on outcome measurement. The RAL cost analysis is also particularly limited, given that there is likely to be significant cost variability between institutions. There is also wide variation in estimates of operating room opportunity cost, and thus such calculations must be done at the institutional level.

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## Footnotes

• Contributors MTF designed the study, collected and analyzed data, and drafted the paper. He is the guarantor. RVC collected data and critically revised the paper. JAM collected data and critically revised the paper. MRF collected and analyzed data, and critically revised the paper.

• Funding This work was supported by a research grant from EndoPhys Holdings, LLC.

• Competing interests MTF serves as a consultant for Balt USA, Medtronic, Stryker, and Viz.ai and has received research funding from Medtronic, Stryker, Microvention, EndoPhys, and Penumbra. RVC has received research funding from Microvention and Medtronic.

• Patient consent Not required.

• Ethics approval Institutional Review Board.

• Provenance and peer review Not commissioned; externally peer reviewed.

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