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Monitoring involves the use of several technologies to allow for a controlled induction of anaesthesia, maintenance and emergence from anaesthesia.
There are different guidelines concerning monitoring during anaesthesia, illustrated by the Australian and New Zealand College of Anaesthetists recommendations:
1. Continuous electrocardiography (ECG) - placement of electrodes which monitor heart rate and rhythm, as well as showing evidence of other cardiac pathologies (e.g. ischaemic heart disease).
2. Continuous pulse oximetry (SpO2) - Allows early detection of cyanosis and a fall in patients' blood oxygen tension.
3. Blood pressure Monitoring (NIBP or IBP) - Generally non-invasive methods of measuring blood pressure such as a dinamap(TM) or machine which continuously checks blood pressure non-invasively. Alternatively, for major surgery such as cardiac surgery, anaethetist s may use invasive monitoring with an arterial cannula .
4. Agent concentration measurement - Common anaesthetic machines have meters to measure the percent of inhalational anaesthetic agent used (e.g. sevoflurane, isoflurane, desflurane, halothaneHalothane vapour is an inhalational general anaesthetic. Its systematic name is 2-Bromo-2-chloro-1,1,1-trifluoroethane. Once widely used as general anaesthetic, it has largely been replaced by sevoflurane and isoflurane for human use. Halothane is still w etc).
5. Low oxygenOxygen is the chemical element in the periodic table that has the symbol O and atomic number 8. The element is very common, found not only on Earth but throughout the universe. Molecular oxygen (O, often called free oxygen on Earth is thermodynamically un alarm - Almost all circuits have a backup alarm in case the oxygen delivery to the patient becomes compromised. This warns if the fraction of inspired oxygen drops lower than room air (21%) and allows the anaethetist to take immediate remedial action.
6. Circuit disconnect alarm - indicates failure of circuit to achieve a given pressure during mechanical ventilationsee Mechanical ventilation (disambiguation) for other meanings. In medicine, mechanical ventilation method to assist or replace spontaneous breathing. Mechanical ventilation can be life-saving and is a mainstay of CPR, intensive care medicine, and anesthe.
7. Carbon dioxideCarbon dioxide is an atmospheric gas composed of one carbon and two oxygen atoms. One of the best known of chemical compounds, it is frequently called by its formula: :CO (pronunciation: "see oh two") Carbon dioxide results from the combustion of organic measurement ( capnography )
Muscle relaxation, also known as neuro-muscular blockade , allows surgerySurgery is the medical specialty that treats diseases or injuries by operative manual and instrumental treatment. Its practitioners are referred to as surgeons''. History of surgery Although surgeons are now considered to be specialised physicians, the pr within major body cavities , eg. abdomenThe abdomen (from the Latin word meaning "belly") is the part of the body between the pelvis and the thorax. The front of the abdomen is the abdominal cavity, which is separated from the thoracic cavity by the diaphragm. The lining of the abdomen is calle and thorax without the need for very deep planes of anesthesia, and is also used to facilitate endotracheal intubation .
Muscle relaxation causes paralysis of the muscles of respiration, ie. the diaphragm and intercostal muscles of the chest, and therefore requires that some form of artificial respiration be implemented, usually by connection of the patient to a mechanical ventilator. The muscles of the larynx are also paralysed so that the airway usually needs to be protected by means of an endo-tracheal tube.
Muscle relaxants work by antagonising the natural transmitter substance acetylcholine at the neuromuscular junction. Thus, nerve impulses which would normally cause muscles to contact are prevented from reaching their supplied muscles, causing the muscles to relax.
Monitoring of muscle relaxation is most easily provided by means of a peripheral nerve stimulator. This device intermittently sends short electrical pulses through the skin over a peripheral nerve while the contraction of a muscle supplied by that nerve is observed. The effects of muscle relaxants are commonly reversed at the termination of surgery by anticholinesterase drugs .
Examples of skeletal muscle relaxants in use today are pancuronium, rocuronium atracurium and succinylcholine.