Life-threatening anaphylaxis is a type I hypersensitivity reaction, occurring in latex sensitised individuals on re-exposure to the antigen latex. Latex proteins cross link with the IgE antibody, lead to mast cell degranulation. This releases histamine, leukotrienes and prostaglandins and these result in profound vasodilatation, myocardial depression and bronchospasm. If a known case of latex allergy comes to the theatre what precautions should you take? Should be placed first on the operating list. Premedication with anti-histamines chlorpheniramine, ranitidine , corticosteroids.
Theatre needs thorough cleaning prior to this case unoccupied for at least 2 h. Ensure full awareness of all staff involved with the patient. Latex free box equipments, synthetic gloves, etc. Having a database of latex free equipment. Induce in the operating theatre.
Handbook of Anaesthesia & Peri-operative Medicine
Clear, visible signs on doors to theatre. Availability of resuscitative drugs and equipments to manage anaphylaxis.
Describe the management of anaphylaxis. Immediate management: Stop administering the possible offending agents. Epinephrine 0.
Intravenous fluids. Secondary treatment: anti-histamines, corticosteroids. Bicarbonate therapy as guided by blood gas analysis. Blood sample for mast cell tryptase should be taken 1 after treating the reaction as soon as possible 2 About 1 h after the reaction and 3 6 h after reaction. Elevated serum tryptase after an anaphylactic reaction indicates mast cell degranulation.
Later, all the events should be documented. The patient should be tested for an adverse drug reaction. Once the drug responsible for the event is identified, patient and the general practitioner should be informed in writing. After discussion with the patient, medic alert bracelet should be arranged.
The event should also be reported to the Committee on Safety of Medicines. How would you investigate for the suspected drug or causative agent for anaphylaxis? Patient should be referred to the immunologist with complete details of the drugs given during the event and full description of the event. Skin prick testing is the most commonly performed test a drop of diluted drug solution is placed over the forearm skin, and then skin is punctured using a small gauge needle.
Occasionally intradermal testing using more dilute solution may be required. The skin tests are usually carried out 46 weeks after the reaction. Radio-allergo absorbent test RAST is an alternative investigation.
- Population Genetics: A Concise Guide.
- ebook$ The Structured Oral Examination in Anaesthesia: Practice Paper…!
- Wind Walker (Titus Bass, Book 9);
As it is performed in vitro, there is no risk of anaphylactic reaction during the test. It is less sensitive than a skin test and more expensive. Physics, clinical measurement and safety 1 Key topics: humidification, capnography, filters Q1 Humidification Define water vapour pressure.
It is the pressure that would be exerted by water vapour if it alone occupied the space. It is expressed as kPa. What do you mean by the term saturated water vapour pressure? It is the maximum attainable water vapour pressure at a given temperature. Note: The maximum amount of water vapour that can be present in a given volume of air is determined by the temperature.
What is absolute humidity? What is relative humidity? Relative humidity is the ratio of the mass of water vapour in a given volume of air to the mass required to saturate that given volume of air at the same temperature. Define dew point. Dew point expressed in C is the temperature at which condensation occurs when the gas is cooled. What does BTPS stand for? What is the isothermic saturation boundary ISB? Alveolar gas is said to be at BTPS conditions i. Gas conditions are constant and therefore gas exchange is efficient.
It is the humidity that must be added by the upper airways to condition the inspired air for optimal gas exchange in the alveoli. What determines the ISB level? Normally it is just below carina but its position varies according to the volume, temperature and humidity of the inspired gases and with tracheal intubation, which bypasses the upper airway. It lies further down the airway as the volume increases, temperature and humidity decrease and after endotracheal intubation. During inspiration air is heated and humidified so that its temperature and relative humidity increase as gas passes down the upper airway.
Much of the heat and moisture exchange takes place in the nose, where heat and moisture of expired gases is conserved. Classify humidification equipment. Humidification can be active or passive. Active : Adds water vapour to a flow of gas independent of the patient. Example: heated humidifiers, nebulisers. Passive: Returns a portion of the exhaled moisture or rely on a chemical reaction with exhaled CO2 to humidify the expired gas. Example: heat and moisture exchangers HME , circle absorbers.
Describe how HMEs function.
Handbook of Anaesthesia & Peri-operative Medicine
HMEs consist of a layer of either foam or paper that is generally coated with a hygroscopic salt such as CaCl2. The expired gas cools as it passes through the device and condensation occurs, releasing the massive enthalpy of vaporisation to the HME layer. The hygroscopic salt reduces the relative humidity of the gas to below saturation level by chemically combining with the water molecules, although some water vapour is lost into the breathing system. On inspiration, the absorbed heat evaporates the condensate and warms the gas.
The hygroscopic salt, to which the water molecules are loosely bound, releases the water molecules when the water vapour pressure is low. The inspired gas is therefore warmed and humidified to an extent that depends on the moisture content of the expired gas, and hence on the patients core temperature and the condition of the airways and lungs. What is the efficiency of HME humidifiers? The efficiency of the system declines over time and a filter is recommended only for a maximum period of 24 h.
What are the potential problems with their use? Add dead space that can cause increase in PaCO2 unless total ventilation is increased to compensate.
- A Students Guide to Einsteins Major Papers;
- Elseviers Treatise on Geochemistry [9 Vols, no index];
- Pancakes And Waffles!
- Foreign exchange : a practical guide to the FX markets.
- Customer Reviews.
- Primary Exam Resources | blsa.
Increased resistance to gas flow. This may affect patients ability to wean from mechanical ventilation and may affect the triggering of some ventilators. May be particularly marked if liquid e.