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Home based oxygen therapy For Severe Pulmonary Hypertension

Dr Hetan C Shah Assoc Professor of cardiology Sheth G S Medical CollegeKEM Hospital,MumbaiConsultant Interventional CardiologistJaslok Hospital

Outline• Introduction

• Historical aspects

• Clinical Effects of O2 Therapy

• Indications in pulmonary Hypertension

• Oxygen Delivering Devices

• Techniques of administration

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Introduction

“Who can tell but that in time this pure air may become a fashionable article of luxury”

Joseph Priestly

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History• Joseph Priestly, Wilhelm Scheele and Antoine Lavoisiere

discovered oxygen independently in eighteenth century

• Lavoisiere named it oxyge'ne

• John Cotes and Alvan Barach- First administered oxygen to patients with COPD to relieve dyspnea and improve exercise capacity

• Campbell - Controlled Oxygen Therapy for safe continuous treatment

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Home based Oxygen therapy

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• Long-term oxygen therapy (LTOT)

• Nocturnal oxygen therapy (NOT)

• Ambulatory oxygen therapy (AOT)

• Palliative oxygen therapy (POT)

• Short burst oxygen therapy (SBOT).

LONG-TERM OXYGEN THERAPY

LTOT can be defined as oxygen used for at least 15 h per day in chronically hypoxaemic patients.

Chronic hyperaemia is defined as a PaO2 ≤7.3 kPa or, in certain clinical situations, PaO2 ≤8.0 kPa.

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Clinical effects of domiciliary Oxygen

treatment• Improves the function of all Hypoxia sensitive

cells

• Effects on-

1. Survival

2. Neuropsychiatric function and Quality of Life

3. Pulmonary Circulation

4. Erythropoietic System

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Effect Of O2 on Survival

• Studied in detail in patients with COPD

• Hypoxemia and Pulmonary hypertension - increase airflow limitation- Decrease survival

• Continous O2 delivery decreases mortality from 71% to 30% in patients of COPD with cor pulmonate

8 Petty et al 1960

NOTT Study

• 12 hrs/day O2 vs 24 hrs/day O2 in patients of COPD

• % of patients surviving at 12, 24,and 36 months was higher in 24hrs/day group (p<0.01)

9Nocturnal oxygen Trial Therapy Group, Ann Intern Med 1980;93:391

Survival in patients of COPD on Long Term Oxygen

therapy

10Nocturnal oxygen Trial Therapy Group, Ann Intern Med 1980;93:391

MRC Study

• 15 hrs/day O2 Vs No O2 in COPD pts with Cor pulmonale

• Survival notably higher in patients receiving Long Term O2

11Report of the Medical Research Council Working Party,

Lancet 1981; 1: 681

Survival in patients of COPD on Long Term Oxygen

therapy

12 Report of the Medical Research Council Working Party, Lancet 1981; 1: 681

Individuals with less severe hypoxemia may not derive survival benefit from LTOT.

Trials with Survival Benefit

Trials with No survival benefit

PaO2 <60mmHg(7.98kPa)

<69mmHg(9.18kPa)

Effect on Neuropsychiatric

function• Brain represents only 2% of adult body mass , but receives 20 %

of cardiac output

• Chronic hypoxia leads to

Cognitive impairment (Perceptual learning, Problem solving , memory and simpler motor skills) and

Emotional disorders (High level of anxiety, stress and Depression)

• Treatment with continuous O2 improved Cognitive function ( Recent Memory and speed of Work)

14 Krop et al, Borak et al

Effects of LTOT on sleep

• Ventilation–perfusion mismatch during sleep can lead to- Nocturnal hypoxemia, Decreased functional capacity Nocturnal hypoventilation particularly pronounced during REM sleep

• This in turn can lead to poor sleep quality with sleep fragmentation.

• Use of LTOT corrects nocturnal SaO2, decreases sleep latency and improves sleep quality evaluated by EEG.

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Improved quality of life

Demonstrated in a prospective study that measured health related quality of life (using the St. Georges Respiratory Questionnaire [SGRQ]) before and after six months of LTOT delivered via a concentrator.

Prior to therapy, health related quality of life was worse among the patients with COPD who had hypoxemia (and had already been receiving LTOT for at least six months via a cylinder), compared to patients with COPD who were not hypoxemic.

After six months of LTOT, health-related quality of life had improved and was similar in both groups.

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Effects on Pulmonary Hypertension

• Alveolar Hypoxia is a potent pulmonary vasoconstrictor and leads to increased PAH

• It is generally considered important to maintain oxygen saturations at 90% at all times.

• The use of supplemental oxygen may decrease the need for phlebotomy, and reduce the incidence of neurologic dysfunction and complications.

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• The effect of LTOT on PAP are small.

• NOTT trial, survival after 8 years was related to the decrease in mean PAP during the first 6 months of treatment.This subgroup analysis also showed improvement in PAP and stroke volume in patients with 24 h of oxygen therapy per day compared to those given only 12 h of oxygen per day.

• MRC trial, LTOT prevented a rise in PAP of 0.4 kPa (3 mm Hg), seen in the control group, although a fall in PAP was not found.

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Predictors of Long Term response to Continuous Supplemental

Oxygen Therapy

• Decrease of the mean PAP greater than 5 mmHg after 24 hours of 28 % oxygen therapy

• High peak oxygen consumption (VO2) after symptom-limited exercise (>6.5 cc/kg per min as determined by a 30 second collection of expired gas in an airtight collection bag)

19Ashutosh K, Dunsky M. Noninvasive tests for responsiveness of pulmonary hypertension to oxygen. Prediction of survival in patients with chronic obstructive lung disease and cor pulmonale. Chest 1987; 92:393.

Effect on Erythropoietic

systemSupplemental oxygen therapy reduces secondary polycythaemia,as seen by a fall in haematocrit and red cell mass. LTOT in patients with a low haematocrit have worse survival than patients with high hematocrits (>0.55).

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Pulmonary hypertension may occur in a number of pulmonary vascular disorders which can all predispose tohypoxaemia.

There is no evidence of the effectiveness of LTOT in RCTs in patients with pulmonary hypertension, with theexception of those patients who develop pulmonary hypertension as a complication of their COPD.

LTOT in patients with pulmonary hypertension

Evidence statement

▸ The use of LTOT in patients with pulmonary hypertension may improve tissue oxygenation and prevent complications associated with hypoxaemia rather than lead to a specific survival benefit. Evidence level 4

Recommendation ▸ LTOT should be ordered for patients with pulmonary

hypertension, including idiopathic pulmonary hypertension, when the PaO2 is ≤8 kPa. (Grade D)

22The BTS Guideline for Home Oxygen Use in Adults, Thorax, 2015 July

Evidence statement For Hypercapnia during O2

Treatment• Patients with baseline hypercapnia can undergo LTOT

assessment without adverse outcome but require monitoring of pH and PCO2 levels during and at the end of assessment. Evidence level 4

Recommendation

• Patients with baseline hypercapnia should be monitored for the development of respiratory acidosis and worsening hypercapnia using ABGs after each titration of flow rate, as well as ABG sampling after oxygen titration is complete. (Grade D)

23The BTS Guideline for Home Oxygen Use in Adults, Thorax, 2015 July

Evidence statements for flow titration

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• Patients for whom LTOT is ordered at a single flow rate suffi- cient to achieve PaO2 >8 kPa (60 mm Hg) at rest demon- strate a survival benefit from LTOT. Evidence level 1+

• LTOT ordered at a single flow rate to provide adequate oxygenation at rest may offer inadequate oxygenation during exercise and/or sleep. Evidence level 3

• LTOT ordered for patients at different flow rates for use during sleep and exercise demonstrates a survival benefit from LTOT.Evidence level 1+

The BTS Guideline for Home Oxygen Use in Adults, Thorax, 2015 July

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▸ Patients eligible for LTOT should be initiated on a flow rate of 1 L/min and titrated up in 1 L/min increments until SpO2 >90%.

▸ An ABG should then be performed to confirm that a target PaO2 ≥8 kPa (60 mm Hg) at rest has been achieved. (Grade B)

▸ Non-hypercapnic patients initiated on LTOT should increase their flow rate by 1 L/min during sleep in the absence of any contraindications. (Grade B)

▸ Patients initiated on LTOT who are active outdoors should receive an ambulatory oxygen assessment to assess whether their flow rate needs to increase during exercise. (Grade B)

The BTS Guideline for Home Oxygen Use in Adults, Thorax, 2015 July

Recommendations

EQUIPMENT FOR HOME OXYGEN THERAPY

The equipment for home oxygen therapy can be divided into three categories: oxygen source (concentrators, cylinders andliquid oxygen)

oxygen delivery (cannulae, masks, conserversand tracheal devices) and supplementary equipment (humidifiersand equipment to carry oxygen).

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Portable oxygen systems

• Lightweight compressed gas cylinders

• Liquid oxygen systems

• Portable Oxygen concentrators

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Portable oxygen sourcesHeavy, Cumbersome, and Limited in the duration of

oxygen supply,

Oxygen conserving devicesOxygen therapy more efficient,

More portable

Less intrusive

Continous Flow Nasal Canula

 Continuous flow oxygen delivery through nasal cannula is the usual prescription for LTOT in hypoxemic patients and, thus, is the standard against which all oxygen-conserving techniques should be compared

29Relation between oxygen flow rate via nasal cannula and the fraction of inspired oxygen (FiO2). Each additional L/min in oxygen flow increases the FiO2 by about 4 percent (shown as a separate block on each sequential column).

Methods of O2 Conservation

In the home setting, oxygen cylinders with limited storage and oxygen concentrators with limited flow range present barriers for patients on long-term oxygen.

Modes of O2 Conservation

A.Reservoir cannulas

B.Transtracheal catheters

C.Demand oxygen pulse devices•Non invasive open ventilator with oxygen

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Reservoir CanulaReservoir cannulas function by storing oxygen in the reservoir space during exhalation, making that oxygen available as a bolus upon the onset of the next inhalation. Oxygen is conserved because the patient breathes a higher concentration of oxygen without increasing flow from the oxygen tank or concentrator.

Reservoir cannulas increase the percent of oxygen in the air that the patient inhales over that delivered by standard nasal cannula and usually enable a reduction in the oxygen flow setting of approximately 25 to 50 percent while maintaining the same pulse oxygen saturation.

Reservoir cannulas can help decrease the flow rate needed for patients on low-flow oxygen, but they are more commonly used to provide a higher concentration of oxygen to patients who require a flow rate of oxygen 4 L/minute or higher.

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Moustache Configuration (Oxymizer)

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Top panel: During exhalation, the membrane in the Oxymizer reservoir cannula is thrust forward, creating a 20 mL chamber. Bottom panel: When the patient is ready to inhale, he/she receives the stored oxygen in addition to the supply oxygen. This allows the patient to become adequately oxygenated at lower supply flows.

Pendant Configuration (Oximizer Pendant)

Fluidic Reservoir canula

The fluidic reservoir cannula is designed to be oxygen conserving across a range of oxygen flow rates. Unlike the Oxymizer mustache cannula, the device does not have an inner membrane.

Use Of Nasal Reservoir Canula

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The reservoir cannulas (Oxymizer and Pendant) set at 0.5 L/min will achieve an oxygen saturation measured by oximetry (SpO2) equivalent to continuous flow at 2.0 L/min - an efficency of 4:1. Similarly, 2.0 L/min will achieve an SpO2 equivalent to continuous flow at 4.0 L/min - an efficiency of 2:1.

Tiep BL. Reservoir cannulas. In: Portable Oxygen Therapy: Including Oxygen Conserving Methodology, Tiep BL (Ed), Futura Publishing, Mt Kisco, New York, 1991.

Delivers oxygen directly into the trachea through a small opening in the neck

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Transtracheal catheters

Physiologic benefit Mechanism

Decrease in dead space

O2 from catheter enters the trachea lower in the airways, decreasing dead space.

Decrease in total inspired minute ventilation

Due to flow from the catheter, less gas is inspired at the mouth, reducing work of breathing.

Increase in CO2 elimination efficiency

Fresh gas flowing from the catheter flushes the area proximal to the catheter tip during expiration, reducing the amount of CO2 that returns to the alveoli with the next inspiratory cycle. In addition, gas exiting the catheter tip at high velocity generates turbulence that enhances gas mixing distal to the catheter tip, increasing CO2 washout. As a consequence, PaCO2 remains unchanged despite a decrease in total inspired minute ventilation.

Demand Oxygen Pulse therapy

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The demand module is interposed between the pressurized oxygen source and the patient. As the patient inhales, inspiratory airflow is detected by pressure changes in the nasal cannula. A solenoid in the module is rapidly opened and closed, enabling a pulse of oxygen to be delivered at the beginning of inhalation Tiep BL. Electronic pulse oxygen. In: Portable Oxygen Therapy: Including

Oxygen Conserving Methodology, Tiep BL (Ed), Futura Publishing, Mt Kisco, New York, 1991.

Methods Of O2 Conservation

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  Reservoir Demand pulseNoninvasive open ventilator with oxygen

Transtracheal catheter (placed surgically)

Mechanism Stores oxygen during exhalation

Delivery during early inspiration

Delivers 50 to 250 mL pulses

Store, bypass dead-space

Efficiency 2:1 to 4:1 3:1 to 7:1 Not available 2:1 to 3:1High-flow 16 L/m Not applicable Larger pulses 16 L/mComfort Adequate Adequate Adequate Good after

insertion; requires daily cleaning

Cosmetics Obtrusive Adequate Adequate Excellent

Complications Rare Mechanical failure

Mechanical failure

Mucous plug, bleeding, malposition

Porszasz J, Cao R, Morishige R, et al. Physiologic effects of an ambulatory ventilation system in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2013; 188:334.

Responsibilities of physicians prescribing long-term oxygen therapy (LTOT)

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Document the need for LTOT in the medical record*Select a qualified oxygen equipment supplierComplete certificate of medical necessity form and specify:1. Oxygen flow at rest, during exercise, and during sleep, where appropriate2. Oxygen delivery systems, including:A. Stationary unitB. Portable or ambulatory equipmentC. Oxygen-conserving device, if desiredD. Nasal cannula or transtracheal catheter3. Justification for portable or ambulatory oxygen, if requested4. Verify that the supplier has correctly restated the prescription before signing

Monitor use and environment (with home oxygen supplier)Reevaluate for possible changes in the prescriptionRenew LTOT, as required

Thank You

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