Ergooximetry: Ergometry with Blood Gas Analysis

Ergooxymetry belongs to the so-called ergometric procedures. Ergometry is a performance test: under physical stress, e.g. on a bicycle ergometer, various physiological parameters such as pulse rate or respiratory rate are measured. A special form of ergometry is the so-called exercise ECG, which is used for the diagnosis of ischemic heart disease (heart disease associated with the loss of vital heart muscle tissue). Ergooximetry is an ergometric exercise test with assessment of pulmonary functional capacity (functional capacity of the lungs or respiratory system) using a blood gas analysis (ABG).

Indications (areas of application)

Ergooximetry can be used first for diagnosis and second for follow-up assessment of pulmonary dysfunction or disease. As part of a comprehensive pulmonary function diagnosis, landmark statements can be made regarding pulmonary (lung-related) and cardiac (heart-related) functional capacity. In addition, ergometry with ABG is used to estimate pulmonary reserve (lung reserve) and, in the field of anesthesia (anesthetic medicine), can provide information about expected postoperative, respiratory (breathing-related) complications.

Contraindications

These are derived here from the contraindications for normal ergometry. The limiting factor is the performance of the cardiovascular system, so that cardiac factors are the primary factors that militate against exercise testing.

Absolute contraindications

  • Acute aortic dissection (synonym: aneurysm dissecans aortae) – splitting of the wall layers of the aorta (main artery), usually caused by a tear in the tunica intima (inner vessel wall) with subsequent hemorrhage between the layers.
  • Acute myocardial infarction (heart attack).
  • Acute myocarditis (inflammation of the heart muscle)
  • Acute perimyocarditis (combined myocarditis and pericarditis).
  • Acute pulmonary embolism – acute carryover of a blood clot from the venous circulation into the pulmonary circulation.
  • Decompensated heart failure (acute worsening of heart failure).
  • Cardiac arrhythmias with impaired hemodynamics (disturbance of the circulatory system).
  • Unstable angina pectoris (“chest tightness”; sudden onset of pain in the heart area).
  • Severe aortic stenosis (symptomatic) – valvular heart defect in which the outflow tract of the left ventricle (heart chamber) is narrowed

Relative contraindications

  • Arterial hypertension (high blood pressure).
  • Arrhythmias (cardiac arrhythmias)
  • AV block (higher-grade) – cardiac arrhythmia in which conduction of excitation between the atria and ventricles at the atrioventricular node (AV node) of the heart is delayed, interrupted temporarily or permanently; i.e., conduction disorder of the heart that may result in a slowed heart rate).
  • Bradyarrhythmia – very slow heartbeat with a rate below 50 beats per minute with no discernible rhythm; occurs primarily in atrial fibrillation (AF) or atrial flutter with AV block
  • Electrolyte disorders – electrolyte levels (blood salts) in the body deviating from normal levels.
  • Physical impairments – e.g. impairment of the skeletal system with limitation of physical performance.
  • Psychological impairments
  • Valve diseases or defects of moderate severity.
  • Cardiomyopathy, hypertrophic-obstructive (heart muscle disease).
  • Stenosis of the main stem coronary arteries – narrowing of one of two major coronary arteries.
  • Tachyarrhythmia (Fast, irregular heartbeat or rapid cardiac arrhythmia).

The procedure

In ergooxymetry, the patient is gradually brought closer to its load limit, for example, on the bicycle ergometer. For this purpose, the resistance of the ergometer is increased in steps and the blood gas analysis (BGA) is taken during the course. In this way, pulmonary (lung-related) functional capacity can be evaluated in comparison to physical performance. The ABG is a standard procedure for analyzing blood gases and is used to measure the gas distribution (partial pressure) of oxygen, carbon dioxide as well as the pH value and acid-base balance in the blood.A falling oxygen partial pressure and a rising carbon dioxide partial pressure can be indications of a pulmonary dysfunction, e.g. a diffusion disorder (gas exchange disorder) within the alveoli (pulmonary alveoli). The expression of the disturbed gas distribution in the ABG is used to estimate the severity of the pulmonary dysfunction. However, when used alone, ergooximetry can only give an indication of a disorder, so further measures should be initiated to establish the diagnosis.

Potential complications

Complications include those that occur when contraindications are not properly followed. In a heart-healthy or lung-healthy individual, complications are not usually expected but cannot be ruled out. The following symptoms may occur as signs of increased circulatory stress or insufficient oxygen uptake:

  • Angina pectoris (chest tightness in rare cases).
  • Cephalgia (headache)
  • Dyspnea (shortness of breath)
  • Palpitations (palpitations)/ tachycardia (rapid heartbeat)
  • Cardiac arrhythmias
  • Hypotension (low blood pressure)
  • Vertigo (dizziness)
  • Pain in the skeletal system or musculature and tendon and ligamentous apparatus.