Bladder tissue oxygen tension monitoring in pigs subjected to a range of cardiorespiratory and pharmacological challenges.
OBJECTIVE
A fall in tissue oxygen tension (tPO(2)) is an early indicator of organ hypoxia in both patients and animal models. We previously demonstrated the utility of bladder tPO(2) in various rodent shock models. As a prelude to clinical testing, we aimed to provide further validation of bladder tPO(2) monitoring in a large animal model undergoing a range of cardiorespiratory insults and vasoactive drug interventions.


METHODS
Anaesthetized, mechanically ventilated, instrumented female pigs (n = 8) were subjected to a range of short-term cardiorespiratory (changes in inspired oxygen concentration (FiO(2)), haemorrhage, positive end-expiratory pressure) and pharmacologic (inotrope, pressor) challenges. Global haemodynamics, arterial and pulmonary blood gases and bladder tPO(2) were measured before and after each challenge.


RESULTS
Bladder tPO(2) values fell in line with increasing degrees of hypoxaemia and haemorrhage, and were restored during resuscitation. These changes often preceded those seen in global haemodynamics, arterial base excess and lactate. The rise in bladder tPO(2) with hyperoxia, performed as an oxygen challenge test, was incrementally blunted by progressive haemorrhage. Dobutamine and norepinephrine both increased cardiac output and global O(2) delivery, but had no effect on bladder tPO(2) or lactataemia in these healthy pigs.


CONCLUSIONS
In this pig model bladder tPO(2) provides a sensitive indicator of organ hypoxia compared to traditional biochemical markers during various cardiorespiratory challenges. This technique offers a potentially useful tool for clinical monitoring.
Bloomsbury Institute of Intensive Care Medicine, Division of Medicine, University College London, Cruciform Building, Gower St, London, WC1E 6BT, UK. a.dyson@ucl.ac.uk
Alex
A
Dyson
Florian
F
Simon
Andrea
A
Seifritz
Olga
O
Zimmerling
José
J
Matallo
Enrico
E
Calzia
Peter
P
Radermacher
Mervyn
M
Singer
D000818:Animals; D015415:Biomarkers; D002316:Cardiotonic Agents / Q000494:pharmacology; D005260:Female; D006439:Hemodynamics; D006470:Hemorrhage / Q000503:physiopathology; D000860:Hypoxia / Q000175:diagnosis*; D010100:Oxygen / Q000378:metabolism*; D010313:Partial Pressure; D011659:Pulmonary Gas Exchange; D012680:Sensitivity and Specificity; D034421:Sus scrofa; D001743:Urinary Bladder / Q000098:blood supply*; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D015415:Biomarkers; D002316:Cardiotonic Agents; D014662:Vasoconstrictor Agents; D010100:Oxygen