Description: Segment 1 Hill narrates over a film of surgery taking place in an operating theatre. He describes how the measurement of blood gases and the pH of a patient's blood is frequently checked during anaesthesia. Hill talks to camera about which systems are the most efficient for measuring blood gas pH - the pH value is the measure of its acidity or alkalinity. Hill demonstrates how this can be measured using electrode potentials and how this can be applied to the study of blood pH levels - he uses animated models to illustrate this. Time start: 00:00:00:00 Time end: 00:06:19:00 Length: 00:06:19:00 Segment 2 Hill continues to discuss, and demonstrate, how pH electrode potentials can be used to measure blood pH levels during anaesthesia. He shows a film in which a pH electrode pair are demonstrated practically. Time start: 00:06:19:00 Time end: 00:09:26:00 Length: 00:03:06:00 Segment 3 Hill shows graphs and a film demonstrating how to make accurate measurements of blood gas pH using a blood pH meter, he describes the way the meter works in depth. He then shows the correct method of taking blood for pH testing as arterial blood must be used and this must be taken from one of the arteries deep in the wrist. Hill now refers to two films: the first shows how blood pH is measured on a non-automatic blood gas analyser machine, the second shows how blood pH is measured on an automatic blood gas analyser machine. After this, Hill shows a table comparing blood gas levels. He then introduces the new technique of direct reading PCO2 electrodes - a sensitive glass electrode which can measure the pH of a blood sample when prepared in a sodium bicarbonate solution. Time start: 00:09:26:00 Time end: 00:17:34:00 Length: 00:08:08:00 Segment 4 Hill shows a film demonstrating the PCO2 glass electrode technique for testing blood gas pH levels. He then introduces the polarographic oxygen electrode which works in a similar way. A film is shown to demonstrate this method. A further film shows demonstrations of both automatic and manual blood gas analysers. Hill then sums up the lecture, reminding the viewer that accurate blood testing and the correct use of blood gas analysis machines is essential to maintain the health of a patient during anaesthesia, or during time in intensive care. Time start: 00:17:34:00 Time end: 00:24:37:06 Length: 00:07:03:06