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Chapter: Essential Anesthesia From Science to Practice : Clinical management : General anesthesia

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Continued post-operative care - Anesthesia

The patient will go through important changes in response to a major operation with anesthesia.

Continued post-operative care

The patient will go through important changes in response to a major operation with anesthesia. The stress of the inflicted surgical trauma will trigger a release of adrenocorticotropic hormones, cortisol, and catecholamines. Catabolism will overpower anabolism; the patient will be in a negative nitrogen balance.

Coagulation changes might further thrombosis. Incisional pain and narcotic anal-gesics can reduce pulmonary gas exchange. Narcotics inhibit the cough reflex, already reduced in the elderly, causing patients to retain bronchial secretions, potentially leading to atelectasis and pneumonitis. Large fluid loads given dur-ing the operation need to be mobilized, yet antidiuretic hormone secretion will favor water and salt retention. An ileus after intra-abdominal procedures often takes days to resolve while nasogastric suction deflates the stomach not without removing electrolytes. In short, many major operations will leave the patient in a greatly debilitated state that can take several days to resolve.

If these processes are superimposed on extensive surgical operations, for exam-ple those affecting heart, lung or brain, the patient will be admitted to the ICU. This will also be true for post-operative patients who come with pre-existing disease processes involving the cardiovascular (congestive heart failure, recent myocar-dial infarction), or respiratory (obstructive lung disease) systems, the central ner-vous system (stroke, tumor), metabolism (diabetes), hepatic or renal systems, or infection. The available frequency of observation, extent of monitoring, and immediacy of care in the ICU does not match what is available in the operating room, but greatly exceeds whatever can be offered on the post-surgical ward.

When we visit the patient on the post-surgical ward, we will not only consult his chart to see the trends in vital signs (cardiovascular, respiratory and temperature) but also assess fluid status and medications prescribed and given. We then talk to the patient to gauge his mental status (up to 25% of elderly patients can take up to a week to become fully oriented, and some 10% have cognitive impairment lasting for months) and to ask about his comfort. We might have to explain that hoarse-ness (from an endotracheal tube) or a sore throat (from an LMA or endotracheal tube) are likely to improve in a day or two. We continue to worry about pulmonary complications, e.g., atelectasis and pneumonitis, which are most likely in elderly men, in smokers, and after operations that involve the upper abdomen and the chest. Being aware that myocardial infarctions are far more likely to occur – many of them silently – on the second post-operative day than in the operating room, we pay special attention to the cardiovascular system. Hypotension, hypertension (often pre-existing), and arrhythmias are not uncommon.

Pain management

As anesthesiologists, we are particularly attentive to the patient’s pain and its management. We now use a widely employed standardized method of assessing pain in adults and children (Fig. 6.2). In children incapable of relating their pain, physical signs can help (Table 6.3). The treatment of pain will be influenced by its severity.

If the patient is unable to take oral medication, we can institute patient-controlled intravenous opioid administration (PCA), a system that enables the patient to trigger an intravenous injection of a predetermined amount of a nar-cotic. 

The PCA pumps can be programmed to deliver a specific volume, then to lock the system for a predetermined period. When the patient pushes a button, a typical program might deliver (into a running intravenous drip) a 1 mL bolus containing 1.0 mg morphine. The pump then goes into a lockout mode, making an additional injection impossible for a preprogrammed period of, for example, 5 minutes. The pump can be programmed to limit the hourly injection to, for example, no more than 12 mg/h. Even that amount will be excessive if the patient were to self-administer the maximum, hour after hour. The dose and the lock-out period have to be tailored for the individual patient. While morphine is the stan-dard, several drugs are available, among them hydromorphone (Dilaudid®) and fentanyl. In addition, for patients who pre-operatively have become tolerant to opioids, a background infusion of the narcotic may be required.

Depending on the operation (some cause much more severe and protracted pain than others; some limit oral intake for a longer period) and the patient (some are much more sensitive than others), a PCA pump might be available to the patient for a day or a week or more. Once narcotics are no longer needed, or the patient can tolerate p.o. intake, oral medications take over. A great variety of drugs are available (see Pharmacology).

Some patients will still have an epidural catheter in place that had served the anesthetic management during a thoracic, abdominal or lower extremity oper-ation and can now be used for pain management. Typically, we infuse a low concentration of local anesthetic combined with a narcotic through the catheter. By combining these drugs, we minimize the amount of motor block (paralysis) from the local anesthetic while limiting narcotic side effects (nausea, itching, and urinary retention) associated with larger doses of opioids. Once we establish a level of analgesia with a bolus injection, an infusion is begun and the patient might regulate the administration of additional drug with a PCA pump (PCEA: patient controlled epidural analgesia). Dose and concentration of local anes-thetic and lock-out period will have to be adjusted for the individual patient and drugs infused. A typical arrangement might deliver 0.2 mg of morphine in 1.0 mL fluid containing 0.25% bupivacaine and a lock-out period of 10 minutes. Other approaches use a continuous epidural infusion alone.

The post-operative recovery will progress slowly. Every day, if all is going well, we can see improvements. Indeed, we can often see the moment when the patient ‘turns the corner’ from negative to positive nitrogen balance. He will start shaving, she will do her hair and even put on lipstick. The patient will begin to eat, and we can switch from parenteral to oral medication. Many patients will be discharged from the hospital with prescriptions for oral analgesics. See the Pharmacology chapter for a list of commonly used drugs, dosages and duration of effect.

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