Arterial blood gas analyses and measurement of SpO2
As a routine practice of our clinic, ABG samples were taken from
punctures of the radial artery without placing an arterial catheter.
Brachial or femoral artery were punctured when arterial blood could not
be taken from the radial artery. The indications of ABG sampling in our
clinic were as follows: a SpO2 below 90%, presence of
unexplained or clinically inconsistent hypoxemia, a significant increase
in the fraction of inspired oxygen (FiO2) to achieve
target oxygen saturation; the presence of acute dyspnea, lethargy or
other signs of carbon dioxide retention in a patient with risk factors
for hypercapnic respiratory failure and patients at risk for metabolic
conditions. If the patient required any oxygen supplementation, oxygen
therapy was administered via low flow oxygen systems, including a nasal
cannula, simple face mask or non-rebreathing mask with the target oxygen
saturation > 90%. All the ABG samples were analyzed within
15 minutes with using the ABL800 blood gas analyzers (Radiometer Medical
ApS, Denmark).
As our standard of care in wards, blood pressure, heart rate, body
temperature and SpO2 of patients were measured and
recorded to patients’ files at least four times a day. The number of
these measurements was increased according to the patients’ clinical
condition. In addition to these daily measurements, SpO2was measured simultaneously with ABG sampling and recorded. We routinely
placed two pulse oximetry probes on both hands finger for at least two
measurements of SpO2 using finger pulse oximeters
(Contec CMS50D Fingertip Pulse Oximeter, Qinhusangdao, China). Then the
mean of SpO2 measurements was recorded to reduce the risk of measurement
error.