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.
Keywords: Compensatory reserve; ICP; Pulse waveform; Spinal cord pressure.