title: Waveform Analysis of Intraspinal Pressure After Traumatic Spinal Cord Injury: An Observational Study (O-64).
abstract: Following a traumatic brain injury (TBI), intracranial pressure (ICP) increases, often resulting in secondary brain insults. After a spinal cord injury, here the cord may be swollen, leading to a local increase in intraspinal pressure (ISP). We hypothesised that waveform analysis methodology similar to that used for ICP after TBI may be applicable for the monitoring of patients with spinal cord injury.An initial cohort of 10 patients with spinal cord injury, as presented by the first author at a meeting in Cambridge in May 2012, were included in this observational study. The whole group (18 patients) was recently presented in the context of clinically oriented findings (Werndle et al., Crit Care Med, 42(3):646-655, 2014, PMID: 24231762). Mean pressure, pulse and respiratory waveform were analysed along slow vasogenic waves.Slow, respiratory and pulse components of ISP were characterised in the time and frequency domains. Mean ISP was 22.5 ± 5.1, mean pulse amplitude 1.57 ± 0.97, mean respiratory amplitude 0.65 ± 0.45 and mean magnitude of slow waves (a 20-s to 3-min period) was 3.97 ± 3.1 (all in millimetres of mercury). With increasing mean ISP, the pulse amplitude increased in all cases. This suggests that the ISP signal is of a similar character to ICP recorded after TBI. Therefore, the methods of ICP analysis can be helpful in ISP analysis.
authors.affiliation: Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
authors.forename: Marek
authors.initials: M
authors.lastname: Czosnyka
authors.affiliation: Department of Neurosurgery, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: Georgios V
authors.initials: GV
authors.lastname: Varsos
authors.affiliation: Department of Neurosurgery, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: Zofia H
authors.initials: ZH
authors.lastname: Czosnyka
authors.affiliation: Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
authors.forename: Piotr
authors.initials: P
authors.lastname: Smielewski
authors.affiliation: Academic Neurosurgery Unit, St George's, University of London, London, UK.
authors.forename: Samira
authors.initials: S
authors.lastname: Saadoun
authors.affiliation: National Spinal Injuries Centre, Stoke Mandeville Hospital, Aylesbury, UK.
authors.forename: Ali
authors.initials: A
authors.lastname: Jamous
authors.affiliation: Academic Neurosurgery Unit, St George's, University of London, London, UK.
authors.forename: B Anthony
authors.initials: BA
authors.lastname: Bell
authors.affiliation: Department of Anaesthesia, St George's Hospital, London, UK.
authors.forename: Argyro
authors.initials: A
authors.lastname: Zoumprouli
authors.affiliation: Academic Neurosurgery Unit, St George's, University of London, London, UK.
authors.forename: Melissa C
authors.initials: MC
authors.lastname: Werndle
authors.affiliation: Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
authors.forename: Marios C
authors.initials: MC
authors.lastname: Papadopoulos
mesh_terms: D015331:Cohort Studies; D006801:Humans; D007427:Intracranial Pressure; D008991:Monitoring, Physiologic; D011312:Pressure; D063177:Pulse Wave Analysis; D012119:Respiration; D013115:Spinal Canal; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D013355:Subdural Space
keywords: Compensatory reserve; ICP; Pulse waveform; Spinal cord pressure