Intraspinal pressure and spinal cord perfusion pressure after spinal cord injury: an observational study.
OBJECTIVE
In contrast to intracranial pressure (ICP) in traumatic brain injury (TBI), intraspinal pressure (ISP) after traumatic spinal cord injury (TSCI) has not received the same attention in terms of waveform analysis. Based on a recently introduced technique for continuous monitoring of ISP, here the morphological characteristics of ISP are observationally described. It was hypothesized that the waveform analysis method used to assess ICP could be similarly applied to ISP.


METHODS
Data included continuous recordings of ISP and arterial blood pressure (ABP) in 18 patients with severe TSCI.


RESULTS
The morphology of the ISP pulse waveform resembled the ICP waveform shape and was composed of 3 peaks representing percussion, tidal, and dicrotic waves. Spectral analysis demonstrated the presence of slow, respiratory, and pulse waves at different frequencies. The pulse amplitude of ISP was proportional to the mean ISP, suggesting a similar exponential pressure-volume relationship as in the intracerebral space. The interaction between the slow waves of ISP and ABP is capable of characterizing the spinal autoregulatory capacity.


CONCLUSIONS
This preliminary observational study confirms morphological and spectral similarities between ISP in TSCI and ICP. Therefore, the known methods used for ICP waveform analysis could be transferred to ISP analysis and, upon verification, potentially used for monitoring TSCI patients.
Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge;
Georgios V
GV
Varsos
Academic Neurosurgery Unit, St. George's University of London;
Melissa C
MC
Werndle
Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge;
Zofia H
ZH
Czosnyka
Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge;
Peter
P
Smielewski
Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge;
Angelos G
AG
Kolias
Academic Neurosurgery Unit, St. George's University of London;
Isaac
I
Phang
Academic Neurosurgery Unit, St. George's University of London;
Samira
S
Saadoun
Academic Neurosurgery Unit, St. George's University of London;
B Anthony
BA
Bell
Department of Anaesthesia, St. George's Hospital, London, United Kingdom; and.
Argyro
A
Zoumprouli
Academic Neurosurgery Unit, St. George's University of London;
Marios C
MC
Papadopoulos
Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge;|Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland.
Marek
M
Czosnyka
D000293:Adolescent; D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D015170:Cerebrospinal Fluid Pressure / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D063177:Pulse Wave Analysis; D012189:Retrospective Studies; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D055815:Young Adult
ABP = arterial blood pressure; CPP = cerebral perfusion pressure; ICP = intracranial pressure; ISCoPE = Injured Spinal Cord Pressure Evaluation; ISP = intraspinal pressure; PRx = pressure reactivity index; SCPP = spinal cord perfusion pressure; TBI = traumatic brain injury; TSCI = traumatic spinal cord injury; biophysics; intraspinal pressure; observation; sPRx = spinal PRx; spinal cord injury