Injektion till katt – injektionsassocierad smärta samt injektioner i praktiken

Sammanfattning: Intramuscular injections to cats can generate strong reactions in some individuals while reactions of the same extent, according to the author, not always are recognized when using the subcutaneous route. The reactions are probably caused by fear, stress and/or pain. When the injection can generate pain one has to take that into account, which can be a limitation in treatment. It is well known that injections generate pain, but knowledge about the cause and processes of the injection-associated pain is limited. This is mainly due to the difficulty in finding objects to study pain on, high cost of use of laboratory animals and difficulty to obtain objective measurements. Although there is evidence that there may be a local muscle injury by intramuscular injection, it is not always that the extent of damage is related to the pain experienced. Facts about the causes of injection-associated pain have been studied in a literature review. Most studies were conducted in humans and rodents, while a few were performed on rabbits and dogs. According to the literature the pain of a subcutaneous injection can be caused by the pH, the buffer concentration, the injection rate and the injected volume. Injections in rabbits and mice showed evidence of inflammation and local bleeding. Factors that seemed to have effect on the pain of an intramuscular injection are the amount of injected fluid and the osmolality of the solution. A small amount of liquid and/or an isotonic solution is said to cause less pain than a larger amount of liquid and/or a hypertonic solution, when studied in humans. After intramuscular injections several studies have shown the presence of creatine kinase in the blood, an enzyme that indicates muscle breakdown. This has been seen in a variety of mammals, such as rats, dogs and humans. However, the relationship between creatine kinase volume and the extent of muscle damage is not completely studied. To get an idea of the injection methods used in animal clinics in Sweden a questionnaire was sent to 50 selected clinics, about their procedures regarding sedation of cats. 37 clinics answered the questionnaire, 19 used intramuscular injections as their prior injection method wile 17 preferred subcutaneous injections. One answered that they used both intramuscular and subcutaneous injections. When asked if cats have a negative reaction to the intramuscular injection, for example by trying to tear, bite or get away all 37 answered yes. The same question regarding subcutaneous injection yielded 33 affirmative and 4 negative answers. The conclusion is that both subcutaneous and intramuscular injections generate pain. When selecting the method of injection, it is important to adapt to the drug and the individual, and be aware of the available options and their pros and cons. It is also important to know which factors may influence the injection-associated pain in order to reduce the pain for the benefit of the patient, but also for the personnel from an injury standpoint.