CLINICAL TESTS
Identification and description of procedure:
Test involves artificially triggering one of the causes of ADH hormone secretion, blood hyperosmolarity,
achieved through hypertonic saline perfusion. At 7h first extraction to ascertain blood sodium and
potassium. A value of Na > 150 mEq/L freezes the test. At 9h place patient on their back. Open a line in
each arm (one for saline and the other for extractions). Infusion is to start 30 min after resting starts,
lasting 2h at a rate of 0.05 ml/Kg/min. Blood extracted at -15', 0, 30' ,60', 90', 120' and 150'. Then water
is to be ingested freely for 2h, quantifying it. Blood drawn again at 0, 15', 30', 45', 60' and 120'. The
following is to be ascertained at each point: Blood pressure and pulse, hematocrit, Na, K, urea, glucose,
osmolarity and ADH. Measure Na, K, urea and osmolarity in urine (every hour). Thirst is assessed with
standard tests: 1. With a visual analogue linear scale for feeling of thirst; 2. With a graphic scale of glasses
of water; 3. With an analogue linear scale for mouth dryness.
Purpose:
Antidiuretic hormone (ADH) triggers, among its key effects, kidney water retention, which triggers a drop
in osmotic pressure of body fluids, and at large doses can trigger a rise in blood pressure. The purpose of
the test is to ascertain the existence or not of ADH secretion, allowing us to rule out hyposecretion such
as in diabetes insipidus.
Benefits:
Reasonable alternatives to this procedure:
Foreseeable consequences of performing the test:
No foreseeable negative consequences.
Foreseeable consequences of not performing the test:
Your physician will not have the required information for accurate diagnosis and the most suitable
treatment of your disease.
Frequent risks:
Feeling of thirst; aside from which no significant risks observed. Puncture site can be painful or at least
uncomfortable. Pain or bruising at puncture site.
Infrequent risks:
Risk of significant rise in blood pressure: test is to bee stopped.
Risks depending on the patient's personal circumstances:
Not to be performed in patients with high blood pressure or heart disease, whereby the patient must
report his/her possible allergies to medicines, problems with coagulation, cardiopulmonary and renal
diseases, existence of prosthesis, pacemakers, current medicines or any other relevant circumstance that
might complicate or aggravate the test. Given the patients current health situation (diabetes, obesity,
immunodepression, hypertension, anaemia, old age...) the frequency or the seriousness of risks or
complications might increase, hence the overall risk is greater.
Adh secretion stimulation test
