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The electrical equipment used in the operating theatre and intensive care unit is designed to improve patient care and safety. At the same time, however, there is the potential of exposing both the patient and staff to an increased risk of electric shock. It is essential for the anaesthetist to have a thorough understanding of the basic principles of electricity, even though these devices include specific…

Introduction Point-of-care (POC) testing is an ever-expanding area of biomedical science and is now essential to efficient patient care. As the name implies, the goal is to collect the specimen to be tested and obtain the results in a short period of time ( Fig. 14.1 ). This ideally should be done at, or at least near, the location of the patient. All processes are integrated…

Continuous positive airway pressure (CPAP) CPAP is a spontaneous breathing mode used in the intensive care unit during anaesthesia and for patients requiring respiratory support at home. It increases the functional residual capacity (FRC) and improves oxygenation. CPAP prevents alveolar collapse and possibly recruits already collapsed alveoli. Components 1. A flow generator producing high flows of gas ( Fig. 13.1 ) or a large reservoir bag…

Patient-controlled analgesia (PCA) PCA represents one of the most significant advances in the treatment of postoperative pain. Improved technology enables pumps to accurately deliver boluses of opioid when a demand button is activated by the patient. It is the patient who determines the plasma concentration of the opioid, this being a balance between the dose required to control the pain and that which causes side effects.…

Invasive arterial pressure monitoring Invasive arterial pressure monitoring provides beat-to-beat real-time information with sustained accuracy. Components 1. An indwelling Teflon arterial cannula (20-G or 22-G) is used ( Fig. 11.1 ). The cannula has parallel walls to minimize the effect on blood flow to the distal parts of the limb. Cannulation can be achieved by directly threading the cannula (either by direct insertion method or a…

Clinical observation provides vital information regarding the patient. Observations gained from the use of the various monitors should augment that information; skin perfusion, capillary refill, cyanosis, pallor, skin temperature and turgor, chest movement and heart auscultation are just a few examples. The equipment used to monitor the patient is becoming more sophisticated. It is vital that the clinician using these monitors is aware of their limitations…

Inhaling dry gases can cause damage to the cells lining the respiratory tract, impairing ciliary function. Within a short period of just 10 minutes of ventilation with dry gases, cilia function will be disrupted. This increases the patienťs susceptibility to respiratory tract infection. Inhaling dry gases has been shown to contribute to the cause of ventilator-associated pneumonia (VAP). A decrease in body temperature (due to the…

Ventilators are used to provide controlled ventilation to maintain oxygenation and removal of carbon dioxide. Many of them have the facilities to provide multiple ventilatory modes that can lead to some confusion. They can be used in the operating theatre, intensive care unit (ICU), during transport of critically ill patients and at home (e.g. for patients requiring nocturnal respiratory assistance). Positive pressure ventilators are overwhelmingly used…

Laryngoscopes These devices are used to perform direct laryngoscopy and to aid in tracheal intubation ( Fig. 7.1 ). They can also be used to visualize the larynx or pharynx for suctioning, removal of foreign body, placing of nasogastric tube and throat packs. Components 1. The handle houses the power source (batteries) and is designed in different sizes. 2. The blade is fitted to the handle…

Face masks and angle pieces The face mask is designed to fit the face anatomically and comes in different sizes to fit patients of different age groups (from neonates to adults). It is connected to the breathing system via the angle piece. Components 1. The body of the mask, which rests on an air-filled cuff ( Fig. 6.1 ). Some paediatric designs do not have a…

Tracheal tubes Tracheal tubes provide a means of securing the patienťs airway, allowing spontaneous and controlled ventilation. These disposable plastic tubes are made of polyvinyl chloride (PVC), which could be clear, ivory or siliconized. As plastic is not radio-opaque, tracheal tubes have a radio-opaque line running along their length, which enables their position to be determined on chest X-rays. The siliconized PVC aids the passage of…

Breathing systems must fulfil three objectives: 1. delivery of oxygen, 2. removal of carbon dioxide (CO 2 ) from the patient and 3. delivery of inhaled anaesthetic agents. These agents are predominantly eliminated by the lungs also, so the breathing system must be able to expel them as necessary. Several breathing systems are used in anaesthesia. Mapleson classified them into A, B, C, D and E.…

Since the late 1960s there has been speculation that trace anaesthetic gases/vapours may have a harmful effect on operating theatre personnel. It has been concluded from currently available studies that there is no association between occupational exposure to trace levels of waste anaesthetic vapours in scavenged operating theatres and adverse health effects. However, it is desirable to vent out the exhaled anaesthetic vapours and maintain a…

The anaesthetic machine receives medical gases (oxygen, nitrous oxide, air) under pressure and provides a continuous and accurate flow of each gas individually. A gas mixture of the desired composition at a defined flow rate is created before a known concentration of an inhalational agent vapour is added. Gas and vapour mixtures are continuously delivered to the common gas outlet of the machine, as fresh gas…

Gas supply Medical gas supply takes the form of cylinders and/or a piped gas system, depending on the requirements of the hospital. Cylinders Components 1. Cylinders are made of thin-walled, seamless molybdenum steel in which gases and vapours are stored under pressure. They are designed to withstand considerable internal pressure. 2. The top end of the cylinder, the neck, ends in a tapered screw thread into…