Manual Single National Disability Rating to Colombia - Decree 917 of 1999 (Part I of II) - Chapter IV

MANUAL SINGLE NATIONAL DISABILITY

(PART I OF II)

CHAPTER IV
4. RESPIRATORY
4.1 General

The purpose of this chapter is to conduct the evaluation of permanent impairment of the respiratory system and its effects on individual performance. It must be remembered that this type of chronic dysfunction is not static, but it may instead be a manifestation of changing processes, so that should make periodic assessments as the natural history of the disease diagnosed.

The quantified lung dysfunction does not correlate directly with the extent, severity or anatomical tissue injury or the symptoms. Therefore, the classification of the deficiency be made based on the criteria in this chapter. Chronic respiratory failure is considered when the barometric pressure of arterial oxygen (PO2) is less than 60mm Hg, with or without elevated blood barometric pressure of carbon dioxide (PCO2) greater than 45 mm Hg. In this case, it is an advanced condition of respiratory disease and the overall deficit corresponds to 40%. 

Functional tests are valuable for the evaluation of respiratory failure only if you have done when the patient is in stable condition, isolated from an acute episode or recurrent provided that all the relevant therapeutic exhausted.

4.2 Classification

The classification of respiratory failure is based on:

1. Dyspnoea

2. Radiographic

3. Degree of functional impairment (lung function tests and arterial oxygen saturation). To classify a respiratory disease in a particular category of disability, must serve at least two of the criteria in each of them. It should be noted that patients with symptoms that fall within the criteria of Class I must have an overall deficit of 0%, although there are demonstrable anatomical abnormality in the respiratory tract.

4.3 PROCEDURES FOR EVALUATING RESPIRATORY DEFICIENCY OF ORIGIN

You must have a careful history and thorough clinical examination, with special emphasis on symptoms and signs of respiratory. There must be a number of diagnostic aids, such as:

1. Chest x-rays in deep inspiration in postero-anterior projection and lateral respiratory and other diagnostic images that are deemed necessary according to pathology.

2. Complete baseline spirometry and bronchodilator.

3. Arterial blood gases at rest and during exercise, oxygen curve and other evidence relevant gases.

4. Diffusion of carbon monoxide pulmonary plethysmography, lung volumes and other necessary functional tests.

5. They may also be necessary other tests such as electrocardiogram, hematocrit and hemoglobin determination.

4.3.1 MEDICAL HISTORY, PHYSICAL EXAMINATION AND DIAGNOSTIC HELP

4.3.1.1 Functional Assessment of Dyspnea Classes:

TABLE No. 4.1: Grades of dyspnea dyspnoea CLINICAL CRITERIA

0 Normal, no dyspnea.

1 The patient can walk the path of the healthy person the same age and constitution on flat ground, but has dyspnea when climbing a hill or stairs.

2 The patient can walk several blocks to his own speed and dyspneic when walking fast on the flat.

3 The patient had dyspnea while walking slowly on flat.

4 The patient has dyspnea at rest and even has to dress, bathe or wash.

4.3.1.2 Spirometry

Once the exam, you should learn at least the Forced Vital Capacity FVC, forced expiratory volume in one second FEV1, the proportion of relationship between these two parameters or Tiffeneau index (FEV1/FVC x 100), expiratory flow forced 25-75% of FVC (FEF25-75%) also called FEMM maximum mean expiratory flow and peak flow PF. The values ​​are expressed in absolute terms and in percentage of expected normal value. Due to the variability of normal values, the lower limit of normality of each of the above indices was set at the 95 percentile of average expected theoretical value, ie the value on which distributes 95% of subjects normal.

TABLE No. 4.1 summarizes the lower limits of normal FVC, FEV, and Tiffeneau IndexFEF25 -75 expressed as a percentage of the theoretical value expected.TABLE No. 4.2: NORMAL spirometric

SEX MALE FEMALE

AGE 12 to 24 25-39 40-85 20-39 40-88

PERCENTAGE%%%%%

CVF 79.88 81.80 73.40 76.90 71.8

FEV1 81.20 78.10 72.20 70.30 72.6

Tiffenau 72-76 72-73 67-72 73-76 74-72

FEF25 -75 58.80 55.30 40.30 44.80 56.90

These values ​​correspond to the 95 percentile of normal mean values, expressed as

percentage of the theoretical value expected.

The pulmonary function tests should not be performed in the presence of asthma attacks or other evidence of bronchospasm. When this has happened, the results should not be taken account for the classification of the deficiency. Nor should they be during or shortly after acute respiratory illness and should be considered the ability of the examinee to understand instructions and their cooperation in conducting the test.

Arterial blood gases are less useful in the evaluation of disability and have value only when represent a permanent condition.

Acute changes in the values ​​of PO2, PCO2 and oxygen saturation should not considered to describe the disability, and no samples should be taken during a bronchospasm or in the course of an acute respiratory illness.

TABLE No. 4.3: GLOBAL IMPAIRMENT OF THE PERSON OF RESPIRATORY DISEASESCLASS CRITERIA TO ASSESS GLOBAL GAPLUNG FUNCTION GASIMETRIA DYSPNEA RADIOGRAPHY (%)

I Standard, with evidence of scarring or inactive disease. Eg pleural scarring. 1

FEV1 or FVC corresponds to 90% of expected normal. Normal 0

II may be normal or with some alterations. 2 FEV1 or FVC altered within the range from the lower limit of normal to 65% predicted. Normal 5-12.4

III As a general rule alterations. 3 FEV1 or FVC altered in a range of 64 - 55% of predicted normal expected. O2 saturation equal to or greater than 88% at rest or exercise. 12.5-24.9

Usually IV abnormalities. 4 FEV1 or FVC are less than 55% predicted normal expected. O2 saturation less than 88% at rest or exercise. 25-35 In determining the overall deficit should be taken into account the criteria and values ​​set out in Tables No. 4.1 and 4.2 for dyspnea and spirometric values ​​respectively.

4.4 Evaluation of some lung diseases 4.4.1 Asthma

Being a disease with different clinical pictures with great functional variations in its evolution, pulmonary function tests can not be regarded as the sole basis of assessment of deficiency. There are patients with normal or acceptable evidence that they have performed very unstable, serious and even lethal. Other tests that show very disturbed may have a good response to appropriate treatment or have a more stable. Therefore only be considered a 40% deficiency in patients with persistent or permanent symptoms crisis impeding the activity during the day or night disturb sleep after exhausting the real therapeutic possibilities, including the cortico steroids when not contraindicated.

In any case be a final assessment within 6 months of observation with appropriate treatment. Pay particular attention to the dose of medication and regular intervals it is received. Should be treated equally hospitalizations, emergency visits and history of its crises with full treatment during a previous period of not less than six months.

4.4.2 Bronchiectasis

In patients with episodes of acute bronchitis, pneumonia, or hemoptysis often occur at least every two months, or with lung function damage due to severe illness should be evaluated according to the criteria applied in TABLE No. 4.3. Be additional factors to take into account, the daily volume of sputum, the nature and frequency of hemoptysis. When adequate medical treatment has failed, well run and is contraindicated surgery but remains purulent sputum over 50 ml, for periods longer than 6 months causes a deficiency of 40%.

4.4.3 Pulmonary Tuberculosis

The evidence of active pulmonary tuberculosis with positive cultures, increasing injury or cave formation are not, by themselves, a basis for determining that a person has a permanent severe damage of lung function. Therefore, the damage will be assessed based on anatomical and functional alterations resulting from the disease. The assessment should always be at the end of specific therapy, unless it is a different disease-resistant poly anti-TB drugs and unable to certain chemotherapy, in which case it should be noted that the deficiency is 40%. In any case, permanent damage will be assessed lung function due to extensive disease and should be evaluated according to criteria used in TABLE No. 4.3.

4.5.4 Pleurocutáneas Fistulas

A Pleurocutánea fistula with persistent purulent drainage not subject to surgical correction, should be classified in Class IV of the Table No. 4.3.

4.5.5 Corpulmonale

This injury is in right ventricular hypertrophy secondary to chronic lung disease and its diagnosis confers a deficiency in the chronic condition over 40%. Right ventricular hypertrophy is diagnosed based on ECG R wave showing 5 mm or more in V1 and progressive decrease in amplitude from V1 to V6 RS, echocardiography and radiological study in frontal projections (heart clog) and lateral decrease retrosternal space. (See chapter on cardiovascular disease).

4.5.6. Pulmonary Fibrosis

Should be considered that often these patients have normal or slightly altered PO2 at rest, but have significant desaturation with exercise. In these cases, arterial blood gases should be measured at rest and during exercise, carbon monoxide diffusion usually is reduced, and other tests indicated by the pulmonologist. A fall in arterial oxygen pressure greater than 10 mm Hg is indicative of respiratory failure while the rest is normal PO2, determining a deficiency of 40%. For the diagnosis of pneumoconiosis, is accepted as diagnostic criteria parameters set by the International Classification of Chest Radiographs of the Organization Labour.