Patient preparation
Once the patient was anaesthetised and stable, he was prepared for surgery; this involved clipping the fur and cleaning the skin on the affected limb. Preparation must be done outside the operating theatre, so the hair and dirt do not contaminate the theatre. The surgical site should be free of hair as it can be a source of contamination that will increase the risk of infection during recovery. Although the planned surgical incision may be only small, it is important that the surrounding skin is prepared aseptically so the incision can be extended if required.
Care must be taken when clipping the hair as the skin can be easily damaged, which could cause the patient discomfort and create a point through which bacteria could enter through the skin and cause a perioperative surgical infection. The loose hair should be removed from the patient so it cannot contaminate the site during surgery, then the skin should be cleaned to remove all visible gross contamination.
Chlorhexidine and povidone-iodine are two antiseptic solutions used for skin disinfection; in this case, chlorhexidine was used to clean and prepare the patient. When cleaning the site, the swab should be moved in a circular motion, starting from the planned incision site and moving outwards towards the edge of the clipped area. This means that any contamination from the edge of the clipped patch will not be spread across the surgical site. Cleaning should be performed until all visible gross contamination is removed. Once the patient is moved through to the operating theatre this process should be repeated and then the area should be sprayed with 70 % isopropyl alcohol [ 38 ].
Before the surgery began, a surgical checklist was completed by the team( Appendix 2 [ 14 ], see link on page 56). Similar to the pre-anaesthetic checklist, this checklist is carried out verbally, and is used to encourage communication within the team and limit avoidable mistakes. This checklist includes steps to confirm the patient ' s identity, the adequacy of the depth of anaesthesia, the key steps in the procedure and any risks associated with the surgery [ 13 – 15 ].
Perioperative analgesia
Pain is the conscious perception of a noxious stimulus and is associated with actual or potential physical trauma or tissue damage. Pain produces a highly unpleasant sensation, which can lead to a stress response. This response is produced by the endocrine system and leads to the production of corticosteroids such as the hormone cortisol. Cortisol can delay wound healing and increase recovery times, while also causing depression and, in some cases, aggression in patients. For all these reasons, it is vital to recognise and control pain appropriately [ 39 ]. In this case, pre-emptive analgesia and multimodal analgesia were used to manage the patient ' s pain.
Locoregional nerve blocks are a form of pre-emptive analgesia, which assist in providing balanced analgesia and anaesthesia. They work by selectively binding to the sodium channels in the membrane of neurons to prevent the transmission of nerve impulses. These effects can be local or regional depending on the technique used. The site of a locoregional nerve block must be aseptically prepared and maintained.
Nerve blocks can be challenging to perform and, as a consequence, nerve block failures commonly occur; this can be due to an incorrect injection site, bleeding at the site or an ineffective technique [ 40, 41 ]. Following intubation of the patient in this case, and once adequate anaesthesia was established, a sciatic and saphenous nerve block was performed using 0.5 % bupivacaine, which was administered by the anaesthetist under ultrasound guidance. A locoregional nerve block is helpful not only during surgery but also into the recovery period, as it will reduce the amount of systemic analgesia required and the associated side effects of these drugs [ 41 ].
Multimodal analgesia is a technique whereby two or more analgesic drugs from different classes are administered to a patient. These classes are commonly opioids, non-steroidal anti-inflammatory drugs( NSAIDs) and alpha-2 agonists. The drugs are specifically chosen as they will work together to provide effective analgesia, such that, when combined, lower doses of the drugs can be used than if they were used individually, which reduces the negative side effects of each [ 39 ].
This patient received 0.2 mg / kg of methadone intramuscularly as part of the premedication. Methadone is a Schedule 2 opioid that is commonly used for the treatment of moderate to severe pain and is also used in conjunction with other drugs to provide sedation. It can cause respiratory depression in patients, so it is preferable to use low doses [ 42 ]. The patient was also given a constant-rate infusion( CRI) of ketamine throughout the surgery at a rate of 10 µ g / kg / min, following an initial bolus of 200 µ g / kg. Ketamine is a dissociative anaesthetic drug that affects the central nervous system. It is a non-competitive N-methyl- D-aspartate( NMDA) receptor antagonist, which prevents central hypersensitivity. It can cause seizures, cardiovascular stimulation and muscle hypertonicity in some patients, so low doses are preferred to minimise the risk of these side effects [ 43 ]. The ketamine was administered as a CRI to provide steady and continuous delivery of the drug, compared with the‘ rollercoaster’ effects on circulating drug concentration that are produced when administering intermittent doses [ 44 ]. This multimodal protocol provided the patient with sufficient analgesia, and no further analgesic drugs needed to be administered during the surgery. The multimodal technique also minimised any side effects, providing the patient with a smooth anaesthetic and recovery.
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