Continuous Blood Pressure Monitoring with a Finger Cuff is Unsuitable for Intradialytic Blood Pressure Monitoring - European Medical Journal

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Continuous Blood Pressure Monitoring with a Finger Cuff is Unsuitable for Intradialytic Blood Pressure Monitoring

1 Mins
Nephrology
Authors:
Sabrine Chaara,1,2 Paul Rootjes,1-3 Gertrude Wijngaarden,1,2 Menso Nubé,1,2 Camiel de Roij van Zuijdewijn,1,2,4 *Muriel Grooteman1,2
  • 1. Department of Nephrology, Amsterdam University Medical Center, the Netherlands
  • 2. Amsterdam Cardiovasular Sciences, Diabetes & Metabolism, Amsterdam, the Netherlands
  • 3. Gelre ziekenhuizen, Apeldoorn, the Netherlands
  • 4. Spaarne Gasthuis, Hoofddorp, the Netherlands
*Correspondence to [email protected]
Disclosure:

All authors declared unrestricted grants received by the Amsterdam University Medical Center from Niercentrum aan de Amstel and B.Braun Avitum AG. Grooteman received payment to Amsterdam University Medical Center from Baxter and Fresenius Medical Care Deutschland GmbH, support to attend a meeting from Fresenius Medical Care Deutschland GmbH, and royalties or licenses from Wolters Kluwer. Chaara, Rootjes, Wijngaarden, Nubé, and Zuijdewijn declared no other conflicts of interest.

Citation:
EMJ Nephrol. ;12[1]:45-46. https://doi.org/10.33590/emjnephrol/EONQ7408.
Keywords:
Blood pressure, continuous non-invasive blood pressure monitoring, finger cuff, haemodiafiltration, haemodialysis, intradialytic hypotension.

Each article is made available under the terms of the Creative Commons Attribution-Non Commercial 4.0 License.

BACKGROUND

Intradialytic hypotension (IDH) is the most common complication of haemodialysis (HD). A purely nadir-based definition of IDH (nadir systolic blood pressure [SBP] of <90 mmHg or <100 mmHg, depending on the pre-dialysis SBP) was most strongly associated with mortality; whereas, definitions consisting of symptoms, as outlined in current guidelines, were not.1 The research team recently showed that the vast majority of IDH episodes (98%) are asymptomatic.2 Furthermore, in clinical practice, blood pressure (BP) is routinely measured twice per hour, while additional readings are only performed when symptoms arise. Hence, it is conceivable that the true incidence of IDH might be severely underestimated with the current routine BP-monitoring regimen.

AIMS

As intradialytic BP-drops may induce injury of vital organs, the primary goal is to assess the occurrence of IDH when BP is monitored continuously using a finger cuff (FC).

Yet, first, it appeared essential to validate intradialytic BP measurements using an FC by assessing the level of agreement with the standard oscillometric brachial arterial pressure (oBAP).

METHODS

Forty patients with HD were cross-over randomised to four dialysis modalities, each for 2 weeks: standard HD, cool HD, low-volume haemodiafiltration, and high-volume HDF. BP was measured every 15 minutes with an oBAP, and also every 20 seconds with a non-invasive FC device (ClearSight, Edwards Lifesciences, Irvine). For validation, the same arm sequential BP measurement method was applied. Paired BP measurements were compared with the Bland-Altman method. Bias was defined as the mean difference (MD) between oBAP and FC (oBAP minus FC), and 95% limits of agreement as the MD ±1.96 standard deviation The IDH analysis was restricted to FC measurements with an acceptable level of agreement, defined as a MD of ≤10 mmHg,3 and their corresponding 15-minute interval.

RESULTS

Seventy-five percent of participants were male, the mean age was 69.7 (±13.5 years), and median dialysis vintage was 3.0 years (interquartile range: 1.0–5.8). Diabetes mellitus and cardiovascular disease were present in 48% and 73% of participants, respectively. In 144 dialysis sessions, 33.4% of the FC measurements were missing, of which 43.8% were unexplained.

Validation

The Bland-Altman analysis of 1,221 paired BP measurements revealed a mean bias ± limits of agreement of 13±45 mmHg for SBP and 13±26 mmHg for diastolic BP.

IDH analysis

Twenty-seven percent of the paired BP measurements exhibited acceptable accuracy, resulting in the inclusion of 17,940 FC and 412 oBAP measurements. The FC detected 439 IDH episodes that had a median duration of 40 seconds (two measurements), with 1,703 out of 17,840 measurements meeting the IDH criteria. In contrast, during the same period, only 20 IDH episodes (of 412 measurements) were detected by the oBAP method.

CONCLUSIONS

Continuous BP-monitoring revealed an IDH occurrence which was ±22 times higher than 15-minute interval BP measurements, indicating that the majority of IDH episodes are missed with the current routine regimen.

As the FC showed poor accuracy and precision compared to the oBAP method, this method is, in fact, inappropriate for intradialytic BP-monitoring in patients undergoing HD.

References
Flythe JE et al. Association of morality risk with various definitions of intradialytic hypotension. J Am Soc Nephrol. 2015;26(3):724-34 Chaara S et al. No relation between intradialytic hypotension and physical adverse symptoms. ERA24, 23-26 May 2024. Stergiou GS et al. A universal standard for the validation of blood pressure measuring devices: Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization (AAMI/ESH/ISO) Collaboration Statement. J Hypertens. 2018;36(3):472-8.

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