Answer to question 1.
The central and most important respiratory drive is increase in arterial CO2 tension (Pa,CO2). The increase in PaCO2 stimulates both peripheral central chemoreceptor, firing rate. Increased firing results in increased respiratory rate. In human beings, it is still difficult to distinguish the effect of CO2 on the central chemoreceptors from those on the peripheral chemoreceptors. Brief stimulation, as used in many tests of ventilatory control, does not give an appropriate index of more sustained hypercapnia, as happens in diseases.
Answer to question 2.
Hypercarbic respiratory failure is due to the build up of PCO (hypercarbic)and is often associated chronic lung diseases like COPD.
Hypoxic respiratory failure is due to low paO2 (hypoxia). Here, there is the inability of getting the oxygen to the tissues. Example acute airway obstruction.
Answer to question 3.
Oxygen haemoglobin dissociation curve offers an explanation on how the haemoglobin and oxygen become dissociated under pressures in the human body.
Answer to question 4.
The word incubation refers to maintaining a system under specific conditions in order to promote growth. It has different meanings in chemistry, biology and neonatal intensive care Units.
Infants are cared for in incubators or "open warmers." Nearly all are attached to various types of monitors. Some require respiratory support ranging from extra oxygen (by head hood or nasal cannula) to continuous positive airway pressure (CPAP) or mechanical ventilation.
- Ventilators: To provide adequate ventilatory support to the neonate
- Cardiac monitor: To monitor the neonate's heart function
- O2 sat; Pulse oxymetry
- Temperature probe: To monitor the patient's temperature
Answer to question 5.
Tracheotomy tubes are an adjunct to airway management. Identify one type of tracheotomy tube and give a brief explanation of its characteristics.
There are many types of tracheotomy tubes. In Australia the shiley is the most used.
Side port: To inflate and deflate cuff.
Neck plate: To secure the tracheostomy around the neck of the patient.
Inner Cannula: A smooth cannula which lines the inner side of the tracheostomy. Can be removed and cleaned.
Temporary inner cannula: Inserted when the permanent cannula is being cleaned.
Answer to question 6.
Hypoxia is defined as a state of oxygen deficiency in the body which is sufficient to cause an impairment of bodily functions. Hypoxia is caused by the reduction in partial pressure of oxygen, inadequate oxygen transport, or the inability of the tissues to use oxygen and can be classified in four main groups.
a. Hypoxic Hypoxia is a reduction in the amount of oxygen passing into the blood and is due a reduction of available oxygen. Example: exposure to high altitude. Aviators are most at risk.
b. Hypemic Hypoxia is defined as a reduction in the oxygen carrying capacity of the blood. This could be due to reduced number of red blood cells, a reduction in the oxygen transport capacity of the blood occurs through blood donation, bleeding and/or anemia. Smokers, and persons poisoned by carbon monoxide eperienced this type of hypoxia.
c. Stagnant Hypoxia is an oxygen deficiency due to poor circulation of the blood or poor blood flow. High "G" forces and prolonged sitting in one position, hanging in a harness, cold temperatures, and positive pressure breathing can cause this type of hypoxia.
d. Histotoxic Hypoxia is defined as the inability of the tissues to use oxygen. Carbon monoxide and cyanide poisoning are examples of this hypoxia. Chewing tobacco & alcohol will interfere with oxygen use by body tissues. Excessive alcohol consumption is the most common cause of this type of hypoxia.
Answer to question 7.
- Nasal Prongs: Advantage - convenient, cheap well tolerated by many patients. Inaccurate %age of oxygen delivery. Easily removed by patient.
- Venturi mask: Relatively more expensive, Not tolerated by some patients. Smell of plastic and claustrophobia are the most often cited complains by users. Can deliver an accurate percentage of oxygen.
Answer to question 8.
The carina is the proposed radiographic landmarks for the proper positioning of central venous catheters in the adult patient. The possibility of using the carina as a radiographic landmark for the identification of proper positioning of the CVC tip in paediatric patients
Has already been proposed and is awaiting approval.
ETT placement is deemed correct if the tip is at least 2 cm cephalad to the carina on the CXR.
Answer to question 9.
Premature ventricular contractions are sometimes known as "extrasystoles". They are "extra" pulses or heartbeats. PVCs often arise from an irritable area of the myocardium, in the heart's lower pumping chambers. These are called the ventricles. The PVCs interrupt the normal heart rhythm and cause an irregular beat to be palpated or picked up on the ECG. This is often felt as a "missed beat" or a "flip-flop" in the chest by the patient. Some PVCs are harmless. When they occur very often or repetitively, they can lead to many serious Cardiac rhythm disturbances.
