Monday, August 5, 2019
Preparations Prior to Surgery
Preparations Prior to Surgery Table 6. Common adverse reactions during administration of local anaesthetics and their management 34 Box 2: Useful guidelines while administering local anesthesia 33 Box 3: Local anaesthesia in special situations: 30,31,32 Intradermal test dose is done to check for hypersensitivity to local anaesthesia. 0.5 to 1.0mL of test solution undiluted and containing no epinephrine is injected subcutaneously. The test is negative if no reaction occurs during the 30 minutes following the injection. However, regular use of test dose remains controversial as allergy to LA has been found to be exceptionally low (0.7%). (43) Many cases of reported allergy to LA have been attributed to sensitivity to preservatives used in the solution, such as sodium metabisulfite, rather than an allergy to the anaesthetic agent itself. (33) In some dermatologic procedures, often patients are averse to use of local injections for anaesthesia while use of topical anaesthesia may not be sufficient to alleviate their discomfort.. In these patients, vibration can be used to reduce the pain of injections. It may even be used as a substitute for anaesthesia by pharmacological agents in certain dermatological procedures like botulinum toxin injection, laser therapy, cautery of facial warts, incision and drainage of abcesses, etc. Their action is defined by the gate control theory of pain. The A -à ² nerve fibers which transmit mechanoreceptor signals like touch, vibration, stimulate the inhibitory interneurons in the spinal cord which in turn reduce the amount of pain signal l transmitted by A-à ´ and C fibers from thes kin. Thus, counter stimulation, akin to stroking or pinching the skin, can alleviate pain sensation. (44) Cold temperature in the form of ice packs or ethyl chloride sprays has also been used for these purposes (cryo analgesia) The accountability of a dermatosurgeon towards his patient who requires surgery, not only lies in performing the procedure well but, actually begins from collecting all the medical information about him, counselling him and chalking out a plan that has his best interest in mind.(45) It is prerogative to work up the patient completely before he is taken up for surgery to avoid any adverse events. The workup should include a complete history and clinical examination, relevant investigations, counseling, and documentation. 46 A detailed history of co-morbidities and concomitant medication is taken. Concurrent conditions like diabetes mellitus, cardiovascular disease, infectious diseases should be inquired upon. History regarding bleeding tendencies should also be taken. Wound healing is delayed in diabetes due to associated vasculopathy, decrease in the peripheral blood supply and increased risk of infections, hence the blood sugar levels should be monitored and brought under control before surgery. Also, these patient should be given a broad spectrum antibiotic prophylactically. 47,48 For patients with cardiovascular disease, a sublingual nitroglycerin is kept handy in case of a possible precipitation of angina. Adrenaline maybe avoided in cases of hypertension or peripheral vascular disease.49, 50 Electrosurgical procedures are avoided in patients with pacemakers.51 In pregnancy, local anaesthesia is used without adrenaline to avoid chances of uterine artery spasm. Safer antibiotics are prescribed and salicylates and NASIDS are avoided as they can interfere with the growth of the foetus. 39 A detailed drug history is imperative as certain drugs meddle with the haemostatic, inflammatory and wound healing processes. Hence, these drugs need to be stopped for a certain period, after the advice of the physician. 52History of allergy to any drugs, ingested or applied, allergy to adhesive tapes, history of keloid formation, scarring tendencies should be asked in detail. Box 4 gives the important drugs to be taken into consideration while planning a surgery Box 4: Important drug history that need to be asked for prior to a dermatosurgery Local examination of the site to be operated should be done to check the condition of the overlying skin, and to rule out any infection. The dermatosurgeon should have a thorough knowledge of the underlying vital structures so as to avoid any trauma while performing the procedure. Thorough examination also provides signs of keloidal tendency, for e.g in pre existing scars. If the lesion to be operated upon is suspected to be premalignant or malignant, then it is prudent to perform a biopsy first to confirm the findings on histopathology and then decide the next line of treatment. To prevent post ââ¬âoperative infections check for damaged ,infected skin, diabetes, debilitation, hypogammaglobulinaemia, severe malnutrition, long ââ¬âterm antibiotic therapy, corticosteroids, immunocompromised states, emotional stress, poor hygiene, etc. Counselling is an important constituent of the management of any dermatosurgical procedure. The problems and needs of the patient are assessed, and all the options are put forward for him to decide. Patients need to have a thorough knowledge of the procedure, the complications, the follow-up, post-operative care, outcome of the surgery, must be given to the patient. All queries about the procedures duly addressed. Expected results should be explained. Any unrealistic expectations need to be put to rest then and there. Patients with unrealistic expectations should be counselled against the procedure Baseline investigations that should be done before a dermatosurgical procedure are listed in box 5. It is, however, not necessary to do the whole list of investigation prior to a minor dermatosurgical procedure. The investigations that need to be carried out should be based on the results of the clinical examination. Box 5: Investigations to be carried out prior to a dermatosurgical procedure. Complete documentation of the case is a very important part of preoperative preparation. All the relevant clinical notes, photographs should be kept as record for medicolegal reasons. A written informed consent is of paramount importance. Drugs that are prescribed before a major dermatosurgery are mentioned in box 6. However, this is again not mandatory and is based on the patient profile, nature of the surgery and surgeonââ¬â¢s experience Box 6: Preoperative drugs prior to a dermatosurgery Dermatosurgeon must undertake strict safety measures in order to prevent hazardous infections. As mentioned earlier hand hygiene plays a major role in preventing iatrogenic infections. Right technique of hand washing reduces contamination and prevents the transfer of infection from one man to another. Personal protective equipment (PPE) is a protective gear that comprises of mask, gloves, gowns, goggles and shoes. A high quality PPE is the only barricade between the surgeon and the infectious material. 23. All the instruments required for the surgery should be kept ready in the instruments trolley before the surgery. The surgical trolley should also have surgical drapes, adequate amount of gauze pads, cotton swabs and surgical disinfectants in place. The order of keeping the instruments on the trolley should be predetermined and kept uniform for a particular surgery so as to maintain a smooth flow of operation. Also, the emergency tray should always be ready in order to deal with any critical situation. The area to be operated upon has to be cleaned and shaved if required. Disinfection of the surgical area is done by using disinfectants like povidone iodine and methylated spirit. The cleaning of the area should always be started from the centre extending into the periphery in order to ensure minimum possible risk of contamination of the site of operation. Sterile drapes must then be used to isolate the surgical area. Excision means cutting out a tissue, an organ or a tumour. The ellipse (fusiform excision) is the mainstay and workhorse of cutaneous excisional surgery and reconstructive surgery. Proper planning of the incision should be done before the surgery is started. This results in a least noticeable and well healed scar. A well planned incision line should run parallel to the favourable lines of closure i.e. the relaxed skin tension lines (RSTL) or the lines of minimal skin tension (natural skin creases or wrinkles). [Illustration 31.4] These lines can be made obvious by pinching the skin in all direction. They can also be judged by asking the patient to smile or grimace.57,58 The incision line so planned not only makes the scar inconspicuous but it heals faster and has a higher tensile strength. Lines of maximal extensibility are typically at right angles to the RSTL. These lines are important when performing a flap grafting from an adjacent area. Incisions can also be taken along the wrinkle lines, skin folds. Another option is to make a circular incision and wait for some time to allow it to turn into an oval shape after undermining the edges. Before final closure the oval shape can be converted into an ellipse. Always respect the cosmetic units of the face. The cosmetic units of the face are chin , perioral region, cheek, periorbital region, nose, forehead, glabella, and temple. Scars restricted to single cosmetic unit hide well, than the scar crossing multiple units.58 [Illustration 31.5] Nature of the lesion removed is also an important factor. For benign lesions the surrounding normal skin excised is minimal, on the other hand for malignant lesion two factors are very important, complete excision of the tumour and to include sufficient surrounding normal looking tissue in the excision to prevent recurrences. ( 59,60) The shape of the lesion also plays important role in deciding the excision line. For oval shaped lesion the long axis of the incision line must run parallel the long axis of the lesion. This will shorten the length of the scar.[61]. When taking incisions near lips or eyes, functional considerations are very important to prevent lip retraction and ectropion respectively.
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