Why failure in blocks.
Block doesn't work reasons, avoidance, analysis, and strategies.
For many readers a drug “block” a channel as a cork stoppers a bottle. Local anaesthetics block nerve conduction by preventing the increase in membrane permeability to sodium ions that normally leads to a nerve impulse. The success of a regional anaesthetic programme is dependent on patient education and the support of the surgical team. To put a patient ease it is desirable for the surgeon to inform the patient about the possibility of receiving a block for his /her surgery prior to the day of surgery. In addition, the training, education, and skill of the individual performing the block are of paramount importance. There are few absolute contraindications for a block. Patient refusal, local anaesthetic allergy, infection at the site of needle injury. A patient that is unable to co-operate secondary to decreased mental status is also an absolute contraindication. Regional anaesthesia is not contraindicated in patients that have a pre-existing stable neurological deficit or chronic neurological disease provided that the condition is well documented. An in-formed co-operative patient is an essential factor in ensuring safe and effective regional anaesthesia. Patients and family members should receive clear instructions regarding the anticipated duration of the block and how to transition to oral analgesia at home to avoid the sudden onset of pain. Regional anaesthesia still awaits the development of the ideal local anaesthetic drug. Modern local anaesthetic drugs are sufficiently effective and safe for the majority of the clinical practice, but the search for agents, better nerve fibre selectivity, less degree of motor blockade and lower incidence of systemic toxicity continues. Essential knowledge of local anaesthetics includes understanding of the chemical and physiochemical properties of the molecules, their absorption, their disposition and their elimination. All of them are influencing to a varying extent, the production of effective and safe nerve blocks. Regional anaesthesia is just applied anatomy and as such a comprehensive knowledge of the anatomy is essential. Anatomic variation is common, and the path and area of innervations of peripheral nerves may be variable. It is important to know the innervations of the structures being operated on and the proposed surgical approaches and incision. Patient factors may well affect success; choice of the patient and the choice of the technique are most important, as anxious patients do not make ideal regional candidates. The environment in which regional anaesthesia is performed may influence the success as when hurried or pressurised your performance will suffer and failure rates will increase. No clinician or technique can sustain a 100% success rate due to the many variables that exist between the patient, clinician and the environment. Success in regional anaesthesia is itself is a variable. Whatever your end point is, regional anaesthesia is an inherent failure rate, what's important is whether your failure rate is acceptable and what strategies you should employ to minimize failure and how to deal with it. Regional anaesthesia is a practical skill that has to be learnt and as such has a definite learning curve; the main determining factors of this learning curve are clinician himself, the teaching available and the number cases that they are exposed to. To learn a procedure adequate exposure to sufficient numbers is important and the learning curve for techniques can to an extent be expressed as minimum numbers need reach a certain level/ consistency. We all look different. This is also true for topographical anatomy (the relationship between anatomical structures) to some extent. The sub specialty of regional anaesthesia challenges clinicians with the “must have” of a profound anatomical knowledge. The sub speciality of regional anaesthesia challenges clinicians with the “must have” of a profound anatomical knowledge.