Blood Pressure Monitoring in Critical Care Retrieval: Why South African Retrieval Systems Need to Rethink Reliance on NIBP

A recent study published in the Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine by Perera et al. (2024) has sparked a timely conversation about the reliability of non-invasive blood pressure (NIBP) monitoring in the prehospital critical care environment. The findings? In short: NIBP is not always helpful, especially in the patient at the extremes of Blood Pressure.

In a retrospective analysis of over 2,300 paired readings, the authors compared NIBP cuff measurements with invasive blood pressure (IBP) monitoring in a UK-based HEMS service.

The study showed significant discrepancies, particularly in patients at the extremes of perfusion, such as those in haemodynamic shock or with severe hypertension. In fact, NIBP overestimated blood pressure in hypotension and underestimated it in hypertension, with concerning implications for prehospital treatment decisions like fluid resuscitation, pressor use, and airway management. Everyday we make decisions to start or stop these criticalinterventions based largely on a number on a screen (and hopfeully the patient's clinical presentation too). BUT - as we know, the numbers are not always accurate.

This finding is not new—but it’s newly urgent for South African systems.

Why This Matters in Africa (and other resource limited settings)

South African prehospital systems are growing. Helicopter and ground-based retrieval services are expanding their scope, reaching more critically ill patients in remote and rural areas. But unlike UK or European systems, most African HEMS and critical care transport services operate in environments where:

• Invasive arterial lines are rarely placed prehospitally due to staffing, equipment, and training constraints

• Vital sign interpretation drives nearly every clinical decision, from triage to treatment

• Blood pressure targets in trauma, TBI, sepsis, and obstetric emergencies are not optional—they are essential to survival

• Pre-hospital scope does not allow for the insertion of these invasive monitoring tools in the SA setting.

• Device limitations are common: worn cuffs, mis-sized applications, patient movement, and vibration from air or rough terrain transport often go unnoticed but significantly degrade accuracy

The Clinical Consequences

Perera et al.’s findings underscore what many South African African providers have long intuited: NIBP is not enough when perfusion hangs in the balance. Misreading hypotension risks missing a crashing bleed. Underestimating MAP may mean missing the window to prevent secondary brain injury in head trauma. In hypertensive emergencies, particularly common in eclampsia or post-arrest states, inaccurate BP readings may delay antihypertensive therapy or falsely reassure crews.

For providers operating in under-resourced or rapidly evolving environments, this becomes a matter of patient safety!

So What Should We Do?

Train smarter

Focus training on recognising the limitations of NIBP. Teach providers to use clinical correlation, pulse pressure estimation, manual confirmation techniques, and signs of end-organ perfusion as triangulating tools. Practice the thinking that can lead to better patient interactions and test the limits of the equipment in training.

Push for access to IBP in retrieval settings

Where possible, equip HEMS teams with the tools and training to place arterial lines. If the UK can move towards this as standard, high-performance teams in Africa should not be far behind!

Audit the data

Use this study to trigger local review. How often do BP readings guide life-saving decisions? Are there near misses? Start capturing and comparing non-invasive readings against in-hospital IBP to assess real-world concordance. How can we better equip teams without IABP to make better decisions in real time with challenging perfusion situations?

Advocate for context-appropriate device validation

Most NIBP devices were calibrated on stable, normotensive, white adult populations. We need devices tested and validated in real African prehospital environments—across skin tones, shock states, and transport modes.

This one is likely beyond the means of most of us as providers, but should be be pushing the manufacturers to create devices and software that is more representitive of the actual patient populations we treat?

Support system-wide thinking

This is not just a clinician issue. Procurement, logistics, and policy teams need to understand why accurate monitoring is not a luxury—it’s a life-saving standard.

Last thoughts

On a continent where every vital sign carries weight, every intervention must be carefully considered. This study reminds us: the numbers we use to change and adapt treatment must be trustworthy.

Resistance to new technology and the costs and challenges associated with the implementation of these new tools is high, are we doing enough to break through our own bias' to create a safer environment for our patients?

Reference

Perera, Y., Raitt, J., Poole, K., Metcalfe, D., & Lewinsohn, A. (2024). Non-invasive versus arterial pressure monitoring in the pre-hospital critical care environment: a paired comparison of concurrently recorded measurements. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, 32(77). https://doi.org/10.1186/s13049-024-01240-y