Oximeter

An Oximeter helps measure the oxygen level (or oxygen saturation) in the blood. It is useful in measuring the efficiency of oxygen delivery to the peripheral tissues such as the finger, nose and earlobes. A pulse Oximeter helps monitor the blood oxygen levels of patients suffering pulmonary or cardiac diseases such as congestive heart failure (CHF) and chronic obstructive pulmonary disease (COPD). The Oximeter works on the pulsating feature of the blood flow in the arteries and light absorption capacity of hemoglobin to indicate the body's oxygenation status in a Photoplethysmogram (Volumetric measurement obtained through an optical device).

The Pulse Oximeter beams red and infrared light into the capillaries inside the finger. While oxygenated blood absorbs light at 660nm (red light), the 940nm (infra-red) is absorbed preferentially by deoxygenated hemoglobin in the blood. The relative absorption of light is measured by light collecting sensors. This information is then processed to arrive at the oxygen saturation level of the blood. The pulse Oximeter also displays the pulse rate. Factors that affect the accuracy of the pulse Oximeter readings are weak pulse, hypoperfusion (poor blood circulation), vasoconstriction, cold hands, acrylic nails and high altitude.

The oxygen saturation (SpO₂) is measured as a percentage of full capacity. SpO₂ should ideally be between 96% to 99%. When the SpO₂ falls below 92%, it is suggestive of Hypoxemia or Hypoxia. The patient might need oxygen supplementation.

Pulse Oximetry

Pulse Oximetry, a way of assessing oxygen levels, involves attaching a device known as a pulse Oximeter to the patient's finger, toe or ear lobes. It is a noninvasive monitoring or determination of oxygen-hemoglobin saturation of the blood and the pulse.

Indications for pulse Oximetry include the need to monitor the adequacy of arterial oxy hemoglobin saturation and gauge the response of O2 saturation to therapeutic interventions.
SpO2 (a measure of oxygen saturation) is used for continuous and prolonged monitoring as in during sleep, exercise or surgical procedures. Results of SpO2 tests validate the basis for ordering the test by reflecting the patient's clinical condition. Normal Oxygen saturation levels are between 94 - 100 %. If the saturation level falls below 90 %, clinical intervention is required.

Reasons for low Oxygen Saturation (SP02) Levels:

1. Respiratory Conditions such as emphysema, pneumonia or Obstructive sleep apnea (OSA).
2. Poor oxygenation due to suffocation or allergic reaction.
3. Presence of air blockage or lower levels of Oxygen - drowning

A pulse Oximeter is based on the different light absorption characteristics of oxygenated and deoxygenated hemoglobin. Using a Red LED and an Infra-red LED with matching photo sensors, a microprocessor in the device calculates the ratio of oxygenated/deoxygenated blood and based on the surge which occurs at every heart beat (hence pulse), it displays the Oxygen Saturation level along with the pulse rate. The usual precaution with such a device is to use it on a clean finger. Any barrier like nail polish, grease or dirt may hamper the function.

Spirometer: A device that is used to test the air capacity of lungs and the amount of air that enters and leaves the lungs during breathing. Spirometry is the procedure that measures air flow and lung volume. It is used to diagnose respiratory diseases such as emphysema.

Arterial blood gases test: A test to analyze the blood for oxygen, carbon dioxide and bicarbonate content, as well as blood pH (acidity level). These tests are primarily intended to test the effectiveness of respiration.

For the Arterial blood gases (ABGs) Test, Blood is drawn from a peripheral artery (radial, brachial or femoral) via a single percutaneous needle puncture or from an arterial cannula, for a direct measurement of partial pressures of carbon dioxide (PaCO2) and oxygen (PaO2), hydrogen ion activity (pH), total hemoglobin (Hbtotal) and oxy hemoglobin saturation (HbO2).

Pleurisy

Pleurisy is a condition that is caused when the pleura (moist membrane surrounding the lungs and rib cage) is inflamed. Pleurisy or Pleuritis, as it is otherwise referred to, is characterized by fluid accumulation at the site of the inflammation. This fluid makes it difficult to breathe and leads to shortness of breath and cough. It also lays pressure on the lunds and reduced their ability to move freely. Most often, pleurisy is caused by viral infection. It can be the result of lung or heart disease. Diseases such as tuberculosis, pneumonia and rheumatic disease. Pulmonary embolism or rheumatoid arthritis can also bring on an attack of pleurisy. Primary pleurisy occurs when there is inflammation of the pleural tissues from a direct infection or injury on them. On the other hand, secondary pleurisy occurs when it is the result of any other chest disease. Severe pain in the chest is one of the main symptoms of pleurisy. The pain is felt over the chest at the site of the pleural inflammation. Chest pain becomes acute during deep breathing, coughing and sneezing. Other symptoms of pleuritis are dry cough and fever. Pain may also be felt in the neck, shoulder or abdomen.

Diagnostic tests such as chest x-ray and chest ultrasound are used to detect the degree and extent of pleuritis. Thoracentesis involves collection of fluid from the pleural cavity. Removal of this fluid aids easier breathing. A pulse oximeter allows a physician to check the amount of oxygen in the blood. ECG may show any heart-related conditions that could be the cause for pleuritis. Sometimes a sputum sample is taken for analysis.

A patient suffering from pleurisy may be administered oxygen by a mask or nasal prong to facilitate breathing. If a bacterial infection is the cause, it has to be treated with suitable antibiotics. Inflammation of the pleura is reduced with the help of anti-inflammatory drugs or cortisone drugs. Often the patient is advised to rest and limit the strain on the lungs. Painkillers can help in alleviating pain and discomfort.