your oxygen level and pulse rate
Pulse oximeter.
Only your physician is qualified to tell you if this is appropriate for you or not. Each patient has a unique history that only a physician can evaluate.
Doctors can diagnose lice infestations from looking closely at the parts of the body where the patient has been scratching.
Yes, since it will tell you if you are consuming the righ amount of oxygen.
Only a physician would be able to tell you this after very extensive bloodwork.
it tells the phyisican that the patient is not protected from the tetanus infection
You can't. It has to be adjusted by a technician working for the company who provided the machine to you, and only on the order of the physician. After all, an inappropriate pressure could be harmful to the patient. If you think your CPAP pressure is inappropriate, simply contact the physician who prescribed it and tell him or her.
Check for a pulse - and/or breathing !
A=Spirometer(Answered by Teshome Seya)*source-Tbar's medical dictionary.A spirometer is a device that measures the volume of air inhaled and exhaled by the lungs.A spirometer is used to measure breathing.Spirometerspirometeryou donta stethascope. 
The purpose of reading a pulse is to measure the heart rate. The pulse rate can alert us to difficulties in our health, and it a person's pulse is too high or too low, it can indicate some sort of medical issue. The pulse is one of the vital signs that medical personel collect when a patient arrives for treatment or even just a simple examination. A physician or nurse practitioner will want to know a patient's "vitals" as a prerequisite for treatment of just about any kind. Resting Pulse Rate PR < 40 BMP - Below healthy resting heart rates. PR 40-60 BPM - Resting heart rate for sleeping. PR 60-100 BPM - Healthy adult resting heartrate. PR 100 BPM - 220 BPM - Acceptable if measured during exercise. Not acceptable if resting heartrate. PR > 220 BPM - Abnormally high heart rate.
Symptoms are changes that you can tell the doctor or he can see like a headache or a rash. The patient notices it. No instruments are required. Signs are measured using tests or instruments like Blood pressure or pulse. The patient does not notice it. Other signs might be electrolyte balance or glucose concentrations in the blood.
Only a physician can tell you that.