Few interventions in modern trauma care have travelled the arc from physiological intuition to entrenched dogma as cleanly as the augmentation of mean arterial pressure above 85 mmHg in the early management of acute spinal cord injury. For more than two decades this single threshold has shaped the protocols of neurocritical care units, the boilerplate of trauma transfer agreements, and the bedside decisions of intensivists, neurosurgeons, and trauma anaesthetists across both sides of the Atlantic. The publication in September 2025 of the first randomised controlled trial on the question, by Sajdeya and colleagues in JAMA Network Open, has thrown that consensus open in a way that few practitioners anticipated. With the additional weight of a multicentre cerebrospinal fluid drainage trial published by Gee and colleagues in PLOS Medicine in February 2026, and a sharply argued commentary by Morgenstern in the May 2026 First10EM research roundup, the controversy is now firmly back in active clinical debate. For candidates preparing for the Advanced Trauma Life Support provider examination, this is more than an academic curiosity. The haemodynamic management of the patient with cervical or thoracic cord disruption is precisely the kind of disability-stage decision the ATLS framework expects clinicians to make, often within minutes of arrival in the emergency department, and the foundations beneath the long-taught answer are visibly shifting.
The Doctrinal Origins of Augmented Mean Arterial Pressure
The institutional foundation for augmented blood pressure in acute spinal cord injury was laid by the American Association of Neurological Surgeons and the Congress of Neurological Surgeons in their joint 2002 guidelines, reaffirmed substantially unchanged by Walters and colleagues in 2013. The recommendation was to maintain mean arterial pressure between 85 and 90 mmHg for seven days following injury, with the explicit aim of preserving spinal cord perfusion across the autoregulatory failure that follows traumatic cord disruption. The recommendation was, even at the time of its writing, candidly described within the guideline itself as a Level III recommendation supported by low-quality evidence. It drew principally on observational cohorts from Vale and colleagues at the University of Maryland and a small handful of single-centre series that suggested aggressive haemodynamic management might improve neurologic recovery when compared with historical controls. None of these studies was randomised. All were vulnerable to the confounding inherent in retrospective neurosurgical case series, particularly the survivor bias that arises when patients who tolerate higher mean arterial pressures are systematically those with less catastrophic injuries to begin with. Nevertheless, the recommendation diffused rapidly into international practice and acquired the institutional gravity that distinguishes a guideline from a hypothesis.
By the late 2010s, that hypothesis was beginning to fray at the edges. Jordan Squair and colleagues at the University of British Columbia, writing first in Neurology in 2017 and again with refined empirical targets in 2019, made the case that spinal cord perfusion pressure, calculated as mean arterial pressure minus intrathecal pressure, was a more physiologically meaningful target than mean arterial pressure alone. Their observational cohort suggested that a spinal cord perfusion pressure above 50 mmHg correlated more closely with motor recovery than any specific arterial pressure threshold. Sanchez and colleagues, working through the AO Spine Knowledge Forum, reviewed the field comprehensively in 2020 and concluded that the evidence base was substantially weaker than the strength of the consensus would suggest. In 2024, the AO Spine and Praxis Spinal Cord Institute joint guidelines lowered their recommendation to a mean arterial pressure target of 75 to 80 mmHg for three to seven days, a quiet but significant departure from the longstanding 85 to 90 mmHg position.
The Sajdeya Trial: The First Randomised Evidence
The trial published by Ruba Sajdeya, Miriam Treggiari, and colleagues from Duke University and twelve other major United States trauma centres represented the first randomised attempt to test the augmented blood pressure hypothesis directly. Enrolling patients aged 18 years or older with cervical or thoracic spinal cord injury and an American Spinal Injury Association Impairment Scale grade of A, B, or C between October 2017 and July 2023, the trial allocated participants in equal proportions to an augmented mean arterial pressure target of greater than 85 to 90 mmHg or a conventional target of greater than 65 to 70 mmHg, maintained for seven days or until intensive care unit discharge. The primary endpoints were changes in motor and sensory ASIA Impairment Scale scores from baseline to six months.
The results, presented at the Neurocritical Care Society Annual Meeting in Montreal and published simultaneously in JAMA Network Open on the second of September 2025, were striking precisely because they were unremarkable. Across the ninety-two patients followed up at six months, there was no statistically meaningful difference in either motor or sensory recovery between the two arms. Six-month mortality was similar. So were intensive care and hospital length of stay, pain scores, activities of daily living, mobility, and quality of life metrics. Where the trial did show a difference, it was in the direction of harm. Patients managed to augmented blood pressure targets had higher rates of respiratory complications, longer durations of mechanical ventilatory support, and more severe organ dysfunction during their initial hospitalisation. The authors concluded, with notable directness for a publication of JAMA Network Open’s stature, that the findings called into question both the efficacy and the safety of routine blood pressure augmentation in this population.
The reception has been instructive. Justin Morgenstern’s commentary in First10EM, updated in the May 2026 research roundup, captured the prevailing view among emergency and critical care physicians, observing that the guideline recommendation for higher blood pressure targets had never been based on high-quality evidence and that the trial demonstrated harm without benefit. Simon Carley and colleagues at St Emlyn’s reached a more cautious conclusion in their January 2026 review, noting that the trial was underpowered, with only forty-one per cent of randomised patients completing the six-month ASIA assessment owing partly to disruptions caused by the COVID pandemic and partly to a loss-to-follow-up rate that would be considered unacceptable in a properly powered phase three trial. Chacko, writing in his critical care commentary in September 2025, took an intermediate position, accepting that the trial should clearly influence practice while emphasising that the confidence intervals around the point estimates remained wide enough to accommodate either benefit or harm from either strategy. The shared principle was nonetheless clear. The augmented blood pressure consensus could no longer be defended without acknowledging that the only randomised evidence in existence suggested harm without measurable benefit.
Does Targeting Perfusion Rather Than Pressure Rescue the Hypothesis?
The other plausible escape route from the Sajdeya findings was the proposal that the problem lay not with augmentation as such but with the wrong haemodynamic target. If spinal cord perfusion pressure, rather than mean arterial pressure, was the more physiologically relevant variable, then perhaps direct measurement and management of intrathecal pressure through cerebrospinal fluid drainage could achieve the perfusion goals that vasopressor-driven augmentation could not. This was the question put to a multicentre clinical trial by Cameron Gee, Brian Kwon, and colleagues at the International Collaboration on Repair Discoveries in Vancouver, published in PLOS Medicine in February 2026.
Fifty-eight patients with acute spinal cord injury received cerebrospinal fluid drainage via an intrathecal catheter aimed at achieving a target spinal cord perfusion pressure, with comparisons drawn against a historical cohort of eighty-six patients managed according to conventional mean arterial pressure guidelines with a target of 85 to 90 mmHg. The trial was ultimately terminated by the investigators owing to inconsistent protocol adherence across study sites, but its findings nonetheless contributed substantially to the unravelling consensus. The intervention group received an average of 495 millilitres of cerebrospinal fluid drainage across a mean catheter dwell time of 138 hours, with seven participants receiving no drainage at all. There were no significant differences in intrathecal pressure, spinal cord perfusion pressure, or neurological recovery between the protocol-managed and the historically managed cohorts. The hypothesis that direct perfusion targeting would rescue the spinal cord where pressure-driven augmentation had failed was, on this evidence, not supported.
A complementary pragmatic implementation study from Kolcun and colleagues, published in PLOS One in January 2026, demonstrated that spinal cord perfusion pressure monitoring was feasible and free of major procedural complications across two North American sites. Vasopressor support was nevertheless required in close to half of patients, and therapeutic cerebrospinal fluid drainage in just over a quarter, raising the practical question of whether the additional invasiveness of intrathecal monitoring justified the marginal informational gain in a field already burdened with line-related complications and prolonged intensive care stays.
International Guideline Divergence in 2026
The combined effect of the Sajdeya and Gee trials has been to produce one of the most striking guideline divergences in recent trauma practice. The 2013 American Association of Neurological Surgeons recommendation of mean arterial pressure 85 to 90 mmHg for seven days remains the most widely cited threshold in ATLS-oriented teaching materials and in many United States trauma centre protocols. The 2024 AO Spine and Praxis Spinal Cord Institute joint guidelines have moved to a target of 75 to 80 mmHg for three to seven days, a position that now sits awkwardly between the older AANS doctrine and the conventional 65 to 70 mmHg threshold suggested by the new randomised evidence. The most recent meta-analysis on the question, published in the European Spine Journal in 2025 by a group at the University of Toronto, identified an association between below-threshold blood pressure and worse functional outcomes, but acknowledged that adjusted odds ratios were close to unity once known confounders were controlled for, a finding consistent with the proposition that the relationship is one of secondary injury avoidance rather than active augmentation.
The United Kingdom’s position is, characteristically, more conservative. The National Institute for Health and Care Excellence guideline on spinal injury assessment and initial management, NG41, defers to local specialist spinal centre protocols rather than mandating a specific arterial pressure target, focusing instead on the prevention of hypotension and the prompt transfer of patients to definitive neurosurgical and spinal injury units. The British Association of Spinal Cord Injury Specialists, through its Standards for Specialist Rehabilitation of Spinal Cord Injury published in September 2022, has historically recommended maintaining mean arterial pressure above 80 mmHg and systolic pressure above 90 mmHg, a position broadly aligned with the more recent AO Spine target but now under active review in light of the randomised evidence. The European Society for Trauma and Emergency Surgery has yet to issue a formal updated statement. The practical consequence for trainees in the United Kingdom is that the answer to the question of which mean arterial pressure target to apply after acute spinal cord injury depends on which spinal cord centre is receiving the patient, which guideline document was last consulted at the local trust, and the year in which that consultation took place.
Treating Numbers, Treating Physiology, Treating Patients
The accumulating evidence on haemodynamic management in spinal cord injury speaks to a broader pathology in modern trauma care, one that the trauma community has been forced to confront repeatedly across the past three decades. The 85 to 90 mmHg target acquired its authority through the institutional weight of guideline endorsement rather than through randomised evidence. It persisted not because the underlying physiological hypothesis had been confirmed but because the clinical community found no easy way to step away from a recommendation that ran in only one direction of risk. To withhold augmentation, in the absence of a randomised trial, meant accepting the possibility that one was undertreating a recoverable injury. To deliver augmentation meant accepting only the costs and complications of vasopressor administration, which were widely judged to be tolerable. This asymmetric perception of risk is a well-recognised driver of guideline inertia in trauma care.
The Sajdeya trial inverts that calculus. If the only randomised evidence we possess suggests harm without measurable benefit, then the default position must shift. Conventional mean arterial pressure targets of 65 to 70 mmHg become the reasonable starting point until further evidence emerges, with augmented targets reserved for patients in whom hypotension or signs of inadequate end-organ perfusion specifically demand them. This is not the first time that trauma medicine has been forced to confront the difference between treating numbers and treating patients. The protracted controversy over induced hypothermia in traumatic brain injury, the abandonment of high-dose methylprednisolone in spinal cord injury following the NASCIS trials, and the slow retreat from aggressive crystalloid resuscitation in haemorrhagic shock all share a common epistemic lesson. Physiologically plausible hypotheses, supported by observational data and institutional authority, can persist for decades before randomised evidence forces a reconsideration.
Why This Matters for ATLS Candidates
The haemodynamic management of acute spinal cord injury sits at the intersection of three core ATLS domains: circulation and shock management, disability assessment, and the recognition of neurogenic shock. Candidates should be able to distinguish neurogenic shock, a distributive shock state arising from disruption of sympathetic outflow above the sixth thoracic level and characterised by hypotension with relative bradycardia and warm peripheries, from haemorrhagic shock, which remains the more common cause of hypotension in the polytrauma patient and demands a fundamentally different resuscitation strategy. The provider examination has historically expected candidates to commit to an augmented mean arterial pressure target as part of secondary injury prevention, and many ATLS course materials still reflect that position. The new randomised evidence does not invalidate the principle of preventing secondary injury through the avoidance of hypotension, but it does call into question the specific numerical target that has been taught for nearly two decades.
For viva and short-answer questions, candidates should be prepared to discuss the rationale for both conventional and augmented mean arterial pressure strategies, to cite the Sajdeya trial as the first randomised evidence on the question, and to acknowledge the divergence between the 2013 American Association of Neurological Surgeons recommendation, the 2024 AO Spine recommendation, and the post-trial practice now emerging. Examiners increasingly favour candidates who can articulate the limits of guideline evidence rather than recite numerical thresholds without context. Familiarity with the spinal cord perfusion pressure concept and its relationship to intrathecal pressure, an understanding of vasopressor selection in which noradrenaline remains first-line and phenylephrine may be preferred when bradycardia is profound, and an awareness of the ongoing trials will distinguish stronger candidates from those reciting older protocols.