Up into the 1950s, anesthesia claimed about one life of every 2000 anesthetics given. Particularly during the last 30 years, the frequency of anesthesia-related complications leading to morbidity and mortality has decreased markedly, but unfortunately not to zero. No one knows the actual incidence of preventable anesthetic deaths; currently quoted numbers range from 1 in 20 000 to 1 in 200 000 anesthetics; a reasonable estimate probably lying somewhere in the middle of these figures
Anesthetic risks are usually smaller than the risks associated with surgical interventions, but they loom large when general anesthesia or heavy sedation is required for a non-invasive and essentially risk-free diagnostic examination.
For example, when a small child needs anesthesia to hold still for a CT scan or MRI study, anesthesia poses the only risks.
Many drugs used in general anesthesia interfere with ventilation – think of respiratory depression from narcotics, surgical anesthesia depressing reflexes and relaxing the muscles of the upper airway and, worst of all, the commonly used neuromuscular blocking agents, which spare the heart but paralyze the muscles of respiration. Recognition of these potential respiratory problems has led to the widespread use of endotracheal anesthesia, which requires the insertion of a tube into the trachea, another potential for trouble. Tracheal intubation is not always easy, and unrecognized esophageal intubation continues to claim lives. No wonder then that inadequate ventilation and hypoxemia have caused more grief than any other anesthetic complication. No organ depends more on continuous perfusion with oxygen-carrying blood than the brain. The consequences of brain hypoxia range from deterioration of intellectual function to death.
Anesthetics also affect the cardiovascular system by weakening the myocardium, by depressing autonomic control, and by a relaxing effect on smooth vascular muscles. Decreased preload, low cardiac output, and hypotension result with potential disastrous consequences.
Regional anesthesia carries the risks associated with potential local anes-thetic toxicity, resulting in hypotension or convulsions. In addition, the injec-tion of drugs into a nerve plexus, a nerve, or into the epidural or subarachnoid space, carries the risk of physical damage, bleeding, and infection. These com-plications have been known to cause permanent neurologic changes and even paralysis.
Few drugs are free of the potential for triggering an anaphylactic response, which can be difficult to diagnose in a patient under general anesthesia. The resulting severe hypotension and bronchospasm can then threaten the life of the patient.
Anesthetic morbidity is not easily defined but is certainly more common than mortality. Intra-operative hypotension and arrhythmias are common and, unless severe, are not even mentioned as complications. Within hours after general anes-thesia, 25% of all patients may experience cognitive dysfunction; fewer suffer from nausea and vomiting and/or sore throat, and even fewer have peripheral nerve impairment, which usually resolves within weeks. Occasionally, we chip a tooth during tracheal intubation, cause a hematoma with an i.v. catheter, or produce more significant complications with invasive monitors, e.g., a pneumothorax with a central catheter.
In short, anesthesia does pose dangers. This raises the question of how to tell a patient about potential complications in anesthesia or other procedures. Should we pat the patient on the back and say, “Don’t worry, I’ll take care of you”? Or should we enumerate all possible complications? What does the patient need to understand, and what are we legally required to explain? The informed consent process should result in the active participation of an autonomous and competent patient choosing an anesthetic course based on the information and compassionate medical advice. Physicians have been criticized either for being overly paternalistic, or aloof and impersonal. Frequent complaints concern fail-ure to explain findings and/or treatment plans. While it would be ideal for each patient to understand the details of his or her medical care and participate in all decisions, that level of true “informed consent” is unattainable. Patients will almost invariably be cared for by several experts. Even an expert physician in one field cannot fully appreciate the depth of knowledge an expert in another field brings to the table; how much less then can a medically na¨ıve patient hope to understand all ramifications of diagnosis, prognosis, treatment options, and complications?
Informed consent should fulfill both ethical and legal obligations in the physician–patient relationship, including the pros and cons of the anesthetic options and a description of complications with a 10% or greater risk of occur-rence. In addition, rarer complications should be discussed if their disclosure might affect the patient’s decision whether to proceed or seek alternative therapy. Otherwise, it is ethically preferable and legally sound to ask whether the patient wishes to hear about the less common but more serious risks before presenting a comprehensive and dizzying list. For example, enumerating risks of heart attack, stroke and death from anesthesia, need not further upset a patient who is under-going a necessary operation. He already knows he could die from the operation itself or from refusing surgery.
When speaking with patients, before asking for their signature on a document entitled “Informed consent,” we find ourselves confronted by a multi-horned dilemma. We wish to explain our findings and therapeutic options, realizing that the patient has a right to make decisions about his or her care. While we do not wish to be paternalistic, we have the obligation to offer our opinion as to the best treatment plan so that the patient has the benefit of our knowledge. Sometimes, our opinion can be colored by our personal skills; when two treatments are equiv-alent in all aspects, we should prefer the one with which we have more experience. The legally required “informed consent” process, therefore, calls for skillful and compassionate blending of information and guidance covering (i) risks, com-plications and consequences of the proposed treatment, (ii) alternatives, and (iii) conflicts of interest.
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