The use of arterial blood gases in patient management at the Kenyatta national hospital - intensive care unit
Abstract
The role of laboratory tests in patient management in the ICU includes the
diagnosisof patients' conditions and their minute to minute management. The
varioustests done in the lCU are extensive and expensive, only a few of which
are carried out in the lCU support laboratory. Their usefulness depends on their
proper selection and subsequent timely adjustments as necessary in the
treatment of the patient.
lCU care consumes 20% of total hospital charges 37.The high cost of care in the
lCU is partly due to the numerous tests ordered by the medical staff. This study
which was carried out at the KNH-ICU looked into whether one of these tests,
arterial blood gas analysis, was effectively and appropriately being used in the
KNH-ICU and what changes can be made in order to optimize it's usefulness
while reducing the cost of patient care.
A total of one hundred and ninety two ABGs from eighty four patients were
analysedover a period of two months. Of these 121 were on ventilatory support.
Most samples were obtained from patients who had undergone open-heart
surgery (31%). This was also the group that had indwelling arterial cannulae. The
indicationsfor ABGswere most commonly to correct abberant ABGs(51%) and to
titre oxygen (19%). In the later case, 51% had pulse oximeters in concurrent
use.
ABG requests were considered inappropriate in 68 (35%) of the cases.
The contribution to inappropriately ordered ABGs by requests for electrolyte
check could not be quantified although they were noted to have an input.
Improperuse of pulse oximetry was evidently a cause for increased number of
ABG requests.However, their use would only be safe and useful for patients with
SP02 of equal to or more than 95% in whom oxygen was being titred.
In conclusion,it is noted that ABGs are being overutilised in KNH-ICU. The ABG
requests are often inappropriate, with physician response sometimes being
inappropriate.The laboratory, though prompt, was noted to be erratic with
regardsto temperature adjustment aspect of ABG measurements.
The need for written guidelines is recommended in guiding and standardizing
physicians in the request and subsequent followup of ABG reports. Further
education of the clinicopathological practitioners in the KNH-ICU laboratory is
necessaryin proper use and significance of ABGs. A further longer long-term
observational study should then be carried out to ensure that there is an
improvementin the use of ABGsat the KNH-ICU.
Citation
Master of Medicine in Anaesthesia, University Of Nairobi, 2002Publisher
University of Nairobi, School of Medicine