A Nursing Test.

Nursing Quizz. Questions and Answers.

1. Briefly describe the central respiratory drive mechanism, to include neuronal control and the role of chemoreceptors.

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.

2. Briefly explain hypercarbic and hypoxic respiratory failure and give an example of each.

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.

3. Briefly outline the significance of the oxygen haemoglobin dissociation curve.(A simple graph may aid your explanation).

Oxygen haemoglobin dissociation curve offers an explanation on how the haemoglobin and oxygen become dissociated under pressures in the human body.

4. List four (4) pieces of equipment necessary for incubation and give a brief explanation of their function.

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.

1. Ventilators: To provide adequate ventilatory support to the neonate.
2. Cardiac monitor: To monitor the neonate’s heart function.
3. O2 sat; Pulse oxymetry
4. Temperature probe: To monitor the patient’s temperature.

5. Tracheostomy tubes are an adjunct to airway management. Identify one type of tracheostomy tube and give a brief explantion of its characteristics.

There are many types of tracheostomy 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.

6. List the four classifications of hypoxia and give a cause of each.

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.

1. 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.
2. 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.
3. 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.
4. 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.

Identify two commonly used methods of oxygen delivery in your clinical area and explain the advantages and disadvantages of each method.

1. Nasal Prongs: Advantage – convenient, cheap well tolerated by many patients. Inaccurate %age of oxygen delivery. Easily removed by patient.
2. 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.

8. When examining a chest X-ray, describe the correct radiographic position of the central venous line and endotracheal tube.

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.

9. Define and give the diagnostic characteristics, cause and clinical significance of premature ventricular contractions (PVCs)

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.

Ventricular Bigeminy is an example of a PVC. In this pathological state a regular heartbeat is coupled with an irregular heart beat.

10. Identify four physiological factors that influence central venous pressure.

Central Venous pressure is the blood pressure within the venous compartment, it most often describes the pressure in the thoracic vena cava near the right atrium. CVP is an important concept in clinical cardiology because it is a major determinant of the filling pressure, this is often called the preload.

The following factors affect CVP: Cardiac output, Increased blood volume, Venous constriction, Change from sitting to standing position, arterial dilatation, forced expiration (valsalva) and muscle contraction.

11.a) list the criteria for a pathological Q wave.

The appearance of pathological Q waves is the most characteristic ECG finding of transmural myocardial infarction of the left ventricle. The Q wave generally indicates myocardial necrosis, although similar patterns may be produced by other conditions, such as Wolf Parkinson Whyte syndrome and connected transportation of the great vessels.

During acute MI the following changes in ECG are seen: Necrosis is accompanied by Q waves. Injury is accompanied by ST elevation. T wave inversion is seen during ischaemia and all acute infarctions. When recovery is in progress the ST segment is the earliest to change to normal, then the t wave and the Q wave usually persist.

Therefore, the age of the infarction can be roughly estimated from the appearance of the ST segment and T wave.

The presence of the Q wave in the absence of ST and T wave abnormality generally indicates prior or healed infarction.

Although the presence of a Q wave with a 40 msec duration is sufficient for diagnosis, criteria defining the abnormal depth of Q waves in various leads have been established.

For example, in lead I, the abnormal Q wave must be more than 10 percent of QRS amplitude.

In leads II and aVF, it should exceed 25 percent, and in aVL it should equal 50 percent of R wave amplitude.

Q waves in V2 through V6 are considered abnormal if greater than 25 percent of R wave amplitude.

b) Identify the ECG leads that indicate an infarction and the associated coronary artery.

A 12 lead ECG is used to localize the sites of myocardial ischemia and myocardial infarction. Each lead depicts specific areas. The location of the infarct can be detected fairly accurately from analysis of the 12-lead ECG. Leads that best detect changes in commonly described locations are classified as follows:

Inferior (or diaphragmatic) wall: II, II and aVF
Septal: V1 and V2
Anteroseptal: V1, V2, Vf3 and sometimes V4
Anterior: V3, V4 and sometimes V2
Apical: V3, V4 or both
Lateral: I, aVL, V5 and V6
Extensive anterior: I, aVL and V1 through V6

12.a)Briefly explain the modified Monro Kellie Hypothesis.

The Monro Kellie Hypothesis states that the skull is a closed box containing brain, blood, and CSF. If the volume of any one of these components is increased, or a mass is added then the pressure in the head increases. Items which may be added to increase ICP are blood, CSF, and Brain mass.

b)Briefly define cerebral perfusion pressure and complete the equation.

MAP- ICP =CPP

Cerebral perfusion pressure or CPP is obtained by deducting the ICP from the Mean Arterial pressure. The reasoning for the abovementioned equation are as follows:

Increased ICP is the result of different disease processes like traumas, tumours, and bleeds.

Normal ICP: 8-12 mmHg (same units as BP); Dangerous ICP >20. The skull is a closed box containing brain, blood, and CSF. If the volume of any one of these is increased the pressure in the head increases.

Things that can be added to increase ICP are:

1. Blood: EDH, SDH, SAH, ICH (spontaneous or traumatic)
2. CSF: Hydrocephalus, Idiopathic Intracranial Hypertension
3. Brain/Mass: Tumour, Trauma (cerebral contusions)
4. Oedema: Infarct, trauma (diffuse oedema or contusions), tumours

Trauma is the most common cause of ICP. However, increased ICP can occur with many diseases.

Signs of increased ICP include:

1. Nausea/Vomiting, Headache
2. Altered mental status (global cerebral dysfunction)
3. In kids: Bulging fontanels
4. Papilledema
5. Cranial nerve palsies (especially CN VI) as they are pressed on
6. Cushing’s triad: hypertension, bradycardia, & respiratory irregularity
7. Endstage: Blown Pupil.

14. Give a brief explanation of pre, intra and post renal failure. Include in your explanation an example of a clinical condition for each cause.

Pre renal failure: Renal failure due to hypo perfusion of the kidneys. The acute stage of renal failure. Defined by a urine output of less than 0.5ml/kg/hr for 2 hours.

Intra renal failure: Renal failure due to failure of part of the kidney’s system: Renal failure due to intrinsic renal diseases like glomerular diseases, renal tubular diseases, vascular diseases and interstitial diseases. Also includes nephrotoxins, e.g. contrast, aminoglycosides, amphotericin B, rhabdomyolysis and liver failure.

Post renal failure:

• ureteric obstruction
• bladder outlet obstruction
• Foley catheter obstruction