NURS 3664 Lecture Notes - Lecture 8: Oxygen Therapy, Methemoglobin, Nail Polish
Document Summary
Assess the ventilatory status, oxygenation and acid base status. Severe peripheral vascular disease, absence of an arterial pulse. Pulse oximetry uses light absorption at two wavelengths to determine hemoglobin saturation. Pulse oximetry is non-invasive and provides immediate and continuous data. Pulse oximetry does not assess ventilation (pco2) or acid base status. Pulse oximetry becomes unreliable when saturations fall below 70-80%. Technical sources of error (ambient or fluorescent light, hypoperfusion, nail polish, skin pigmentation) Pulse oximetry cannot interpret methemoglobin or carboxyhemoglobin. The radial artery is superficial, has collaterals and is easily compressed. It should almost always be the first choice. Other arteries (femoral, dorsalis pedis, brachial) can be used in emergencies. Make sure you and the patient are comfortable. Assess the patency of the radial and ulnar arteries. Send to lab in short amount of time otherwise specimen decompensates. Acidosis a patient condition that results in acidemia. Alkalosis a patient condition that results in alkalemia.
