Hyperventilation/Asthma/Bronchitis Flashcards
Explain how the changes in blood physiology that occur in hyperventilation syndrome may lead to increased ventilatory effort.
People with HVS may feel that they cannot get enough air. In reality, they have about the same oxygenation in the arterial blood (normal values are about 98% for hemoglobin saturation) and too little carbon dioxide (hypocapnia) in their blood and other tissues. While oxygen is abundant in the bloodstream, HVS reduces effective delivery of that oxygen to vital organs due to low-CO2-induced vasoconstriction and the suppressed Bohr effect
ventilation exceeds metabolic demands, resulting in hemodynamic and chemical changes that produce characteristic dysphoric symptoms. Inducing a decrease in arterial partial pressure of carbon dioxide (PaCO2) through voluntary hyperventilation reproduces these symptoms.
The hyperventilation is self-promulgating as rapid breathing causes carbon dioxide levels to fall below healthy levels, and respiratory alkalosis (high blood pH) develops. This makes the symptoms worse, which causes the person to breathe even faster, which then, further exacerbates the problem.
Hypoxic stimulation leads to hyperventilation in an attempt to correct hypoxia at the expense of a CO2 loss
Respiratory alkalosis is a medical condition in which increased respiration elevates the blood pH beyond the normal range (7.35–7.45) with a concurrent reduction in arterial levels of carbon dioxide.
What is the Bohr effect?
hemoglobin’s oxygen binding affinity (see oxygen–haemoglobin dissociation curve) is inversely related both to acidity and to the concentration of carbon dioxide.[1]
That is, the Bohr effect refers to the shift in the oxygen dissociation curve caused by changes in the concentration of carbon dioxide or the pH of the environment. Since carbon dioxide reacts with water to form carbonic acid, an increase in CO2 results in a decrease in blood pH,[2] resulting in hemoglobin proteins releasing their load of oxygen.
Conversely, a decrease in carbon dioxide provokes an increase in pH, which results in hemoglobin picking up more oxygen.
Describe the pathophysiological musculoskeletal changes you might expect to find in the structures identified in the case above and how these changes might impact on the normal function of the ventilatory system. ( Structures you identify as being significantly compromised in function include the upper two ribs and associated thoracic costo- and inter-vertebral joints, and the accessory muscles of inspiration and associated cervical vertebral joints.)
Ribs: Ribs 1-7 attach independently to the sternum.
Ribs 8 – 10 attach to the costal cartilages superior to them. LAttisimus Dorsi attach to shoudlers - Scalenes - fatigue
Fatigue of the diaphragm causes a decrease in muscle contraction and alternating movements of the abdomen and rib cage, known as paradoxical breathing
The increased diameter of the chest wall can also limit the mechanical effectiveness of the rib cage inspiratory muscles as can be deduced following the Laplace’s law. In addition, based on animal models the mechanical effectiveness of the parasternal intercostals (the most important inspiratory part of the intercostal musculature) can be decreased due to a change in the angle between the parasternal muscle fibres and the sternum (β angle)
Skeletal muscle activation results in an increased production of free radicals and other forms of reactive oxygen species (ROS). The term oxidative stress refers to the structural damage produced by the oxidation of different components (proteins, lipids, nucleic acids) due to the presence of pro-oxidant substances 25. Mitochondria, and both the xanthine oxidase and prostanoid pathways are the potential sources for ROS production during contractile activity
Contractile fatigue develops when the respiratory system is challenged with an excessive mechanical load for an extended duration.
. As the RMs contract more frequently, they require more oxygen and produce more carbon dioxide. The oxygen delivered to the RM gets robbed from other skeletal muscles. So, those muscles begin to experience fatigue.
What management advice would you offer this patient to improve their quality of life while living with hyperventilation syndrome?
Relax - Nervous system
Good diet - Increase antioxidants - Foods that promote Serotonin - decrease inflammation
Breathing Excercises to train the muscles
Acute bronchitis is
self-limiting lower respiratory tract infection (RTI) characterized by inflammation of the bronchi. In more than 90% of cases, it is caused by a virus. Acute bronchitis usually follows an upper RTI and presents with cough, sometimes in combination with sputum, runny nose, chest pain, headache, and malaise.
Auscultatory findings of bronchitis?
Wheezing
Rhonchi
Coarse crackles
