Abstract
Study design
Observational study.
Objectives
To examine the feasibility of meeting the current clinical guidelines for the hemodynamic management of acute spinal cord injury (SCI) which recommend maintaining mean arterial pressure (MAP) at 85–90 mmHg in the days following injury.
Methods
This study examined data collected minute-by-minute to describe the pressure profile in the first 5 days following SCI in 16 patients admitted to the Intensive Care Unit at Vancouver General Hospital (40 ± 19 years, 13 M/3 F, C4-T11). MAP and intrathecal pressure (ITP) were monitored at 100 Hz by arterial and lumbar intrathecal catheters, respectively, and reported as the average of each minute. Spinal cord perfusion pressure was calculated as the difference between MAP and ITP. The minute-to-minute difference (MMdiff) of each pressure variable was calculated as the absolute difference between consecutive minutes.
Results
Only 24 ± 7% of MAP recordings were between 85 and 90 mmHg. Average MAP MMdiff was ~3 mmHg. The percentage of MAP recordings within target range was negatively correlated with the degree of variability (i.e. MMdiff; r = −0.64, p < 0.008) whereas higher mean MAP was correlated with greater variability (r = 0.57, p = 0.021).
Conclusions
Our findings point to the ‘real life’ challenges in maintaining MAP in acute SCI patients. Given MAP fluctuated ~3 mmHg minute-to-minute, maintaining MAP within a 5 mmHg range with conventional volume replacement and vasopressors presents an almost impossible task for clinicians and warrants reconsideration of current management guidelines.
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Data availability
The datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request.
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Acknowledgements
The authors would like to acknowledge the support of our funders—Praxis Spinal Cord Institute, Vancouver Coastal Health Research Institute and Michael Smith Foundation for Health Research—for their support. We thank the patients and their families for providing consent to our data collection that formed the present paper.
Funding
Funding for this clinical trial was primarily received from Praxis Spinal Cord Institute (formerly the Rick Hansen Institute). Additional funds were received from the Vancouver Coastal Health Research Institute and Michael Smith Foundation for Health Research. BKK is the Canada Research Chair in SCI.
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CMG analysed data, interpreted results, and drafted the paper for important intellectual content. AT, LMB, LR, TA, SP, RCM, ND, JS, CGF, and MCF collected data and revised the manuscript for important intellectual content. BKK conceived of and designed the work that led to the submission, interpreted results, and revised the paper for important intellectual content. All authors approved the final version and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
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We certify that all applicable institutional and governmental regulations concerning the ethical use of human volunteers were followed during the course of this research. Ethics approval was received from the University of British Columbia Clinical Research Ethics Board.
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Gee, C.M., Tsang, A., Bélanger, L.M. et al. All over the MAP: describing pressure variability in acute spinal cord injury. Spinal Cord 60, 470–475 (2022). https://doi.org/10.1038/s41393-022-00802-0
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DOI: https://doi.org/10.1038/s41393-022-00802-0
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