C. Aquino-parsons et al., Oxygen tension in primary gynaecological tumours: the influence of carbon dioxide concentration, RADIOTH ONC, 57(1), 2000, pp. 45-51
Citations number
30
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Onconogenesis & Cancer Research
Background and purpose: To assess the effect of inhalation of various high
oxygen content gases (HOCG) with different carbon dioxide concentrations on
the tumour oxygen tension in patients with primary gynaecological malignan
cies.
Materials and methods: Tumour oxygen tension was assessed on two protocols
in those patients with locally advanced visible or palpable primary gynaeco
logical malignancies. Patients were assessed initially while breathing room
air (R/A). After 4 min of inhaling the first HOCG, a second assessment of
the oxygen tension within the tumour was made. After a 10 min rest period w
hile inhaling R/A, the second HOCG was administered for 4 min after which t
he third set of measurements were obtained. Protocol A involved assessing t
he tumour oxygen tension in 12 patients while breathing R/A, 100% oxygen (O
-2) and 5% carbogen (95% O-2, 5% CO2) . For protocol B, tumour oxygen tensi
on assessments of 13 patients while breathing R/A, 2.5% carbogen (97.5% O-2
, 2.5% CO2), and 5% carbogen. Median pO(2) and percentage of values less th
an or equal to2.5 mmHg were assessed.
Results: Regarding protocol A, the median of the median pO(2) values increa
sed from 5 mmHg when breathing R/A to 47 mmHg for 100% O-2 and to 105 mmHg
for 5% carbogen inhalation. The median of the percentage of values less tha
n or equal to2.5 mmHg decreased: 17% for R/A vs. 16% for 100% O-2 (P = ns)
vs. 0% for 5% carbogen (P = 0.015). In protocol B, the median of the median
pO(2) values increased from 3 mmHg when breathing R/A to 73 mmHg when inha
ling 2.5% carbogen and to 72 mmHg for 5% carbogen inhalation. The median of
the percentage of values less than or equal to2.5 mmHg decreased with both
carbogen mixtures compared with room air: 42% for R/A vs. 0% for 2.5% carb
ogen (P = 0.05) and 3% for 5% carbogen (P = 0.015). No statistically signif
icant difference in this parameter was found between the two carbogen conce
ntrations.
Conclusion: Oxygen tension as measured with an Eppendorf pO(2) histograph,
increased with inhalation of the oxygen and carbon dioxide gas mixtures tes
ted. While 100% oxygen inhalation increased the median pO(2) compared with
R/A a significantly greater increase in oxygen tension was seen with inhala
tion of either carbogen gas mixture. Pure oxygen inhalation did not decreas
e the percentage of values less than or equal to2.5 mmHg whereas inhalation
of either 2.5 and 5% carbogen gas resulted in a significant decrease in th
is parameter. Both carbogen concentrations appear equal at increasing the o
xygen tension in primary gynaecological tumours as measured with the Eppend
orf pO(2) histograph. (C) 2000 Elsevier Science Ireland Ltd. All rights res
erved.