Application of oxygen in patients with pulmonary disease

Andreja Šajnić, bacc. med. techn.,

Jadranka Brljak, dipl. med. techn.,

Slavica Šepec, dipl. med. techn.,

Slađana Režić, bacc. med. techn.,

University Hospital Center Zagreb,

Clinic for Pulmonary Diseases Jordanovac,

Croatia.

17th ESGENA Conference

12-14 October 2013

Berlin

The primary function of the respiratory system is to oxygenate blood and eliminate carbon dioxide.

Oxygen is a colourless, odourless, tasteless gas which constitutes approximately 21% of the air at sea level.

Oxygen may be classified as an element, a gas, and a drug. Oxygen is essential for cell metabolism, and in turn, tissue oxygenation is essential for all normal physiological functions.

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History

1727 S. Hale prepared oxygen,

1777 Priestley normal component of air,

Lavoisier absorption of O2 in the lungs,

1920s A. Barach oxygen as a therapeutic agent.

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Oxygen therapy is the adminstration of oxygen at concentrations greater than that in room air to treat or prevent hypoxemia.

Oxygen therapy is a key treatment in respiratory care.

The objective of oxygen therapyPaO2 ≥60mmHg at rest SaO2 of haemoglobin ≥90% during exercise.

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Hypoxia is defined as a condition where the oxygen supply is inadequate either to the body as a whole (general hypoxia) or to a specific region (tissue hypoxia).

Hypoxemia is defined as a decrease in the PaO2 in the blood (<60mmHg) that decreases the SaO2.

Respiratory failure is a condition in which the respiratory system is unable to provide adequate gas exchange.

Hypoxaemic respiratory failure: PaO2 ≤60mmHg.

Hypercapnic respiratory failure: PaCO2 ≥45mmHg.

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Hypoxemia

Mental staus: impairs judgment, short–term memory,

Circulatory system: PH, compensatory tachycardia, ↓ cardiac output, cardiac arrhythmia, myocardial ischemia, impaired left ventricular function, polycythemia,

Psychological disturbances: confusion, disorientation, somnolence, restlessness, irritability,

Subjective: fatigue, secretions, dyspnea, headache,↓ tolerance for activity, visual disturbances,

Objective: flaring of the nostrils, skin color, cyanosis. 6

Indications LTOT

GENERAL INDICATIONS: PaO2 ≤55mmHg or SaO2 ≤88%.

IN THE PRESENCE OF COR PULMONALE: PaO2 <59mmHg or SaO2 <89%, EKG evidencen od P pulmonale, hematocrit >55%, clinical evidence of right heart failure.

SPECIFIC SITUATIONS: PaO2 ≥60mmHg or SaO2 ≥90% with lung disease and

other clinical needs (SA with nocturnal desaturation). Normoxemic patients at rest, PaO2 ≤55mmHg during

exercise PaO2 ≤55mmHg during sleep (indication for SRBD)

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Assessment for LTOT

Reversible conditions (e.g. correcting anaemia), Status as a nonsmoker, Clinical stability on optimal drug therapy (4 weeks).

Clinical, radiological and cardiac assessments, Pulmonary function tests, The six-minute walk test (6MWT), Clinical evaluation for SRBD, Oximetry, ABG.

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Effects of LTOT

In patients with CRF LTOT (>15h/day) Increase survival, Pulmonary hemodynamics, Exercise capacity, Neuropsychological performance, quality of sleep and

life, Reduce cardiac work, arrthymias, Decreases the oxygen cost of breathing, Reduction of secondary polycythaemia, Improved renal function.

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Recommendations for use of oxygen

Improvement in survival with LTOT seems to be proportional to the number of hours of therapy,

NOTT study, 6 months of oxygen significantly improved pulmonary–artery pressure, peripheral vascular resistance, and stroke volume at rest and during exercise. (Continuous or nocturnal oxygen therapy in hypoxemic chronic obstructive lung disease: a clinical trial. Nocturnal Oxygen Therapy Trial Group. Ann Intern Med 1980; 93:391.)

For patients with resting hypoxemia (resting SaO2 88% or <90% with signs of PH or right heart failure), the use of O2 has been demonstrated to have a significant impact on mortality rate. (Longo, D.L., Kasper, D.L., Jameson, J.L., et al. Chronic Obstructive Pulmonary Disease. Harrison's PRINCIPLES OF INTERNAL MEDICINE, 18th Edition, Volumen 1. Harrison's Online, Chapter 260. )

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Application of oxygen therapy

The goal is: PaO2 of 60–70mmHg, with an SaO2 of 90-94%, without elevating the PaCO2 by >10mmHg or lowering pH to <7.25.

Monitor regularly vital signs, pulse SaO2 and ABGs, Encourage patient to cough out secretions, Provide position for optimal breathing, Administer oxygen therapy as indicated, During an acute, severe exacerbation, FiO2 is usually

titrated at the lowest concentration by nasal cannulae 1-2L/min or Venturi mask 24%,

Gradual increases the FiO2 4-7%, Oxygen doses are adjusted until the goal is

accomplished. 11

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Delivery systems for O2 Flow rate L/min FiO2

Nasal cannula 1 – 6 L/min 25 – 40%

Venturi masks Variable24, 28, 31, 35, 40,

60%

Simple facemasks 6 – 10 L/min 35 – 55%

Partial rebreathing mask 10 – 12 L/min 50 - 60%

Nonrebreathing mask 10 – 15 L/min 65 – 95%

Application of oxygen therapy

Watch out for: Worsening hypoventilation SaO2 <89%, Developing severe hypercapnia and CO2 narcosis, (CNS

depression PaCO2 ≥85-90mmHg).

Observed for signs of inappropriate use of oxygen therapy:

Headache, anxiety, cyanotic, drowsiness, confusion, restlessness, abnormal breathing, "aerophagia".

Indication for intubation and mechanical ventilation is the development of acute hypercapnia with significant acidemia (eg, pH<7.20) and/or a marked depression in the level of consciousness.

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Possible outcomes in administering uncontrolled

oxygen therapy The patient's clinical state and PaCO2 may improve or

not change

The patient may become drowsy but can be roused to cooperate with therapy; the PaCO2 generally rises slowly by up to 20mmHg and then stabilizes after approximately 12 hours

The patient rapidly becomes unconscious, cough becomes ineffective, PaCO2 rises ≥30mmHg/h.(25)

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Complications of inappropriate use of oxygen therapy

Precautions when using oxygen therapy Effect of withdrawing oxygen, Bronchodilator treatments using oxygen-driven nebulizers.

The most serious complication of oygen overuse: Respiratory depression, Oxygen toxicity, Absorption atelectasis.

Oxygen delivery equipment may present other problems:

Perforation of the nasal septum, Bacterial contamination, risk of infection (pneumonia).

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Home oxygen therapy

Continuous (24 h/day) or Intermittent use (nocturnal or exercise).

The prescription should always include the source of supplemental oxygen

Gas or liquid, The method of delivery, Duration of therapy during a 24-hour cycle, Flow rate or FiO2 at rest, during exercise and sleep.

Review will be determined by the patient's underlying condition and prognosis. The patient should be reevaluated within 6 months and record of ABGs and oximetry.

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Nursing diagnosis: Impaired Gas exchange

Excess or deficit in oxygenation and/or carbon dioxide elimination at the alveolar-capillary membrane.

EXPECTED OUTCOME: Demonstrate improved ventilation and adequate

oxygenation of tissues by ABGs within client’s normal limits and absence of symptoms of respiratory distress.

ONGOING ASSESSMENT Monitor the patient for changes in orientation and

behavior, Monitor vital signs, Monitor for signs and symptoms of progressive

hypoxemia or hypercapnia.17

INTERVENTIONS INDEPENDENT Position patient to improve and/or optimize ventilation

perfusion abnormalities. Administer low-flow oxygen therapy as indicated. If PaO2

level is significantly lower or if PaCO2 level is higher than patient’s usual baseline, anticipate the following:› Vigorous pulmonary toilet and suctioning,› Increase in FiO2 with use of controlled high-flow

system, Use caution in administration of respiratory depressant,

INTERVENTIONS COLLABORATIVEM Monitor ABGs and note changes, Monitor SaO2 and pulse rate continuously,

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Nursing diagnosis:Activity Intolerance

Imbalance between oxygen supply with demand.

EXPECTED OUTCOME: Patient will show the progress at a higher level of activity

possible.

ONGOING ASSESSMENT Assess for signs and symptoms of activity intolerance, Assess the individual response to the activity; pulse,

blood pressure, respiration, Assess the patient's level of function of the last and

develop training plans based on the status of basic functions.

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INTERVENTIONS INDEPENDENT Establish common goals with the patient, Discuss concept of energy conservation, Reinforce use of controlled breathing techniques during

activity, Enable portable oxygen for the patient during activity, Increase client's activity gradually as allowed and

tolerated.

INTERVENTIONS COLLABORATIVEM Recommend consultation with a physical therapist to

determine the specific training program on the ability of the patient.

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Nursing diagnosis:Deficient Knowledge off a LTOT

Patient is not familiar with the device for the application of oxygen therapy.

EXPECTED OUTCOME: Verbalize understanding of oxygen supplementation and

other therapeutic interventions.

ONGOING ASSESSMENT Assess knowledge base of LTOT, Assess environmental, social, cultural, and educational

factors that may influence teaching plan, Assess congnitive function and emotional readiness to

learn.

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INTERVENTIONS INDEPENDENT Discuss purpose and method of administration for LTOT, Discuss home oxygen therapy: type and use of

equipment; demonstrate how to start oxygen flow and regulate flowmeter,

Discuss flow rate of oxygen at rest, at night, during activity,

Safety precautions, Discuss the need for periodic reevaluation.

INTERVENTIONS COLLABORATIVEM Arrange for visiting nurse to check patient, Refer to local lung association for support groups, Discuss to participte in a pulmonary rehabilitation

program, Instruct the family regarding home oxygen therapy.22

Conclusion

Oxygen therapy greatly contributes to the quality of life in patients with lung diseases.

Oxygen is a drug but inappropriate use can endanger the health of the patient.

The most important aspect is to educate patients on how to apply LTOT, avoid possible complications and preserve quality of life.

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