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Updated: Jun 3, 2026
Cavernous Nerve Stimulation and Recording of Intracavernous Pressure in a Rat
Published on: April 23, 2018
Analysis of clinical outcomes of linear vs. deep stop decompression from 3.5 to 6 atmospheres absolute (350 - 600
Frans J Cronjé1, W A Jack Meintjes, Peter B Bennett
1Division of Community Health, Department of Interdisciplinary Health Sciences, Faculty of Health Sciences, University of Stellenbosch, Stellenbosch, South Africa. fcronje@hbo.co.za
Unlabelled:
Recreational divers are introducing "deep stops" at half the depth (HD-DS) to reduce the risk of spinal DCS with only Doppler evidence to support it. Therefore this research was designed to show the effect of an HD-DS on spinal DCS manifestations by evaluating whether: (1) air diving-induced spinal DCS could be produced in awake, freely moving rats at 3.5-6.0 atm abs (350-600 kPa); and (2) whether the introduction of an HD-DS reduced spinal DCS in such a model. Fifty-one female, Wistar rats (221 to 450 g) underwent one-hour compression at 350 to 600 kPa with seven minutes of decompression with/without a five-minute DS (HD-DS / No-DS). Animals were observed for three hours. Outcomes were classified as: (1) asymptomatic; (2) breathing difficulties; (3) paralysis/weakness; (4) immobility; or (5) death. Eight animals, exposed to 385 kPa air breathing for 60 minutes followed by a three-staged decompression of 7.5 minutes, remained asymptomatic. The profile is known to produce spinal DCS in anesthetized rats. Eleven animals were then used to determine the threshold for DCS: 500 kPa. A total of 14 animals were compressed to 550 kPa (Group 1). Group 1-A (n = 8) No-DS; Group 1-B (n = 6) HD-DS; 18 were compressed to 600 kPa (Group 2). Group 2-A (n = 8) No-DS; Group 2-B (n = 10) HD-DS.
Results:
(1) 385 kPa protocol did not produce visible DCS manifestations in awake rats. The binomial probability of no DCS in this sample size is 0.002818 for the proportion expected from a published report. The binomial probability of no fatalities is 0.005346). (2) No animals developed spinal DCS when assessed by visible paralysis/weakness or immobility, so no difference could be shown. Group 1-A: two deaths; two breathing abnormalities; four asymptomatic. Group 1-B: all asymptomatic. Difference recorded for breathing difficulties (p = 0.0483); none for fatalities (p = 0.2024). Group 2 mortality was 55% (n = 10). Group 2-A and 2-B: no difference for death (p = 0.6063) or breathing problems (p = 0.2084).
Conclusions:
This model could not evaluate HD-DS for the prevention of spinal DCS in rats.
