Chapter 2: Cardiovascular System

Section 2: Self Test

Answers

1. Blood pressure is a combination of the pumping action of the heart and the controlling pressure of the muscular arteries.
2. A significant drop in blood volume (>1 litre) results in the loss of first normal capillary return, then the radial pulse felt at the wrist and then the groin pulse.
3. A significant reduction in blood volume results in reduction of circulation to initially non-vital organs such as skin and muscles, then later on more vital organs such as the kidneys. Significant blood loss causes concern due to the damage it may cause to the kidneys.
4. Shock is where the circulation cannot maintain the needs of tissues in terms of providing adequate volume of blood to them containing oxygen. The likely causes of bleeding are mediastinal emphysema where the entrapped gas can impair the heart's function and tension pneumothorax where entrapped gas in the chest can impair the heart's function.
5. The features of shock are that the subject feels weak, anxious, is breathless, pale, and sweaty with a thready pulse and may have lost capillary return.
6. Treatment is to ensure there is a safe airway, and that the subject's breathing and circulation are satisfactory. If the subject responds to an enquiry about their well being with an answer this means that their airway and cerebral circulation are adequate. In this case the first aider can immediately concern himself to control bleeding. This is done by direct pressure over the bleeding point, reinforced by a pressure bandage. Once this has been achieved, two i.v. Cannulae should be inserted and it is routine to give 2 litres of saline to help support the circulation.