Physiology - Examples for 9.6
Case History 25 : An Old Lady with Abdominal Pain & Vomiting
Initial blood results at 1000hrs in the Emergency Department:
Resuscitation with normal saline with potassium was commenced. At operation, a dense pelvic abscess due to a perforated pelvic appendicitis was found.
Analysis of the initial blood gases collected after resuscitation was underway confirm the metabolic alkalosis (ie significant alkalaemia with elevated HCO3).
Is the respiratory compensation appropriate? The expected pCO2 by rule 6 is about 45mmHg [ie (0.7 x 36) + 20 ]. Respiratory compensation can be variable in metabolic alkalosis but is almost exactly at the expected level in this case. There is no respiratory acid-base disorder present.
The intraoperative gases later in the day are interesting. Hyperventilation has been avoided as this can lead to an acute respiratory alkalosis and cardiovascular deterioration. This is not particularly important in this case though as the metabolic alkalosis has been significantly corrected by this time. Blood gases in ICU the next morning show complete resolution of the alkalosis and a slight respiratory acidosis due to hypoventilation.
Other points:The low albumin indicates chronic poor nutrition. A low albumin level is also a cause of metabolic alkalosis (see section 10.6) and this is relevant in this case. The albumin level fell further with fluid loading.
Initial [Hb] fell with fluid loading and the patient was transfused. The patient had a significant anaemia and the haemoconcentration partly disguished its severity.A lactate level was not measured in this patient. Hypovolaemia and poor perfusion especially if associated with sepsis can cause lactic acidosis and a lactate level will indicate the presence of a mixed metabolic disorder.
Firstly, initial clinical assessment (on the first gas results):
TO BE COMPLETED
Finally, the Clinical Diagnosis: