Postoperative sedation

Opioid antagonists (Table 7.4), predominantly naloxone, are used clinically to reverse the effects of opiates in overdose or postoperative sedation. Naltrexone, which has oral bioavailability, is used for the treatment of narcotic addiction and alcohol dependence. As discussed below (Section 2.2.2.1), peripherally selective antagonists are being evaluated for treatment of constipation and other gastrointestinal side effects associated with opioid agonist use. 

It is employed for pre-and postoperative sedation. It has also been used successfully in the treatment of anxiety, tension and agitation. 

Dose-Ht/w/ , IMinjection as the hydrochloride in doses of 25 to 100 mg every 4 to 6hrs Children 1 mg per kg body weight im for pre-and postoperative sedation. 

A study in patients undergoing an abdominal hystereetomy under alfentanil and midazolam anaesthesia found that although the pharmaeokinet-ies of midazolam were unehanged, postoperative sedation was more pronouneed, when eompared with a group of patients that did not reeeive alfentanil. ... 

This type of pain management is used for postoperative pain, labor pain, and cancer pain. The most serious adverse reaction associated with the administration of narcotics by the epidural route is respiratory depression. The patient may also experience sedation, confusion, nausea, pruritus, or urinary retention. Fentanyl is increasingly used as an alternative to morphine sulfate because patients experience fewer adverse reactions. 

A 52-year-old man was admitted to the hospital for abdominal surgery. He developed complications postoperatively and was intubated 6 days ago. The nurses note an increase in the amount and purulence of his sputum. Attempts yesterday and today to wean the patient off the ventilator have failed. He is sedated but does respond to commands. His temperature is 38.4°C, his blood pressure is 120/84 mm Hg, and his white blood cell (WBC) count is 14.2/mm3 with a cell differential of 76% neutrophils, 4% bands, 16% lymphocytes, and 4% monocytes. 

Benzodiazepine antagonists, such as flumazenil, possess affinity for benzodiazepine receptors, but they lack intrinsic activity. Flumazenil is an effective antidote in the treatment of benzodiazepine overdosage or can be used postoperatively to arouse patients sedated with a benzodiazepine. 

Hypoventilation Monitor patients who have received flumazenil for the reversal of benzodiazepine effects (after conscious sedation or general anesthesia) for resedation, respiratory depression or other residual benzodiazepine effects for an appropriate period (120 minutes or less) based on the dose and duration of effect of the benzodiazepine employed, because flumazenil has not been established as an effective treatment for hypoventilation due to benzodiazepine administration. Flumazenil may not fully reverse postoperative airway problems or ventilatory insufficiency induced by benzodiazepines. In addition, even if flumazenil is initially effective, such problems may recur because the effects of flumazenil wear off before the effects of many benzodiazepines. 

Promethazine Promethazine also is indicated for preoperative, postoperative, or obstetric sedation prevention and control of nausea and vomiting associated with certain types of anesthesia and surgery an adjunct to analgesics for control of postoperative pain sedation and relief of apprehension, and to produce light sleep antiemetic effect in postoperative patients active and prophylactic treatment of motion sickness (oral and rectal only). 

IV Relief of severe pain pain of Ml used preoperatively to sedate the patient and allay apprehension, facilitate anesthesia induction, and reduce anesthetic dosage control postoperative pain relieve anxiety and reduce left ventricular work by reducing preload pressure treatment of dyspnea associated with acute left ventricular failure and pulmonary edema produce anesthesia for open-heart surgery. 

Subcutaneous/IM Relief of severe pain relieve preoperative apprehension preoperative sedation control postoperative pain supplement to anesthesia analgesia during labor acute pulmonary edema allay anxiety. 

Cyclizine has antimuscarinic properties and is a potent anti-emetic, effective for the control of postoperative and drug-induced nausea and vomiting. It has been used to prevent motion sickness, although diphenhydramine and promethazine are more effective. It is available in oral and parenteral formulations. In contrast to many other first-generation antihistamines sedation is not marked. It is available in tablet form as the hydrochloride and in injectable form as the lactate. Because of its anticholinergic action, blurred vision and dry mouth are associated with clinical doses. When given by rapid intravenous injection tachycardia may be a problem. Meclozine is a related drug which, like cyclizine, is used primarily for motion sickness. 

Recovery is sufficiently rapid with most intravenous drugs to permit their use for short ambulatory (outpatient) surgical procedures. In the case of propofol, recovery times are similar to those seen with sevoflurane and desflurane. Although most intravenous anesthetics lack antinociceptive (analgesic) properties, their potency is adequate for short superficial surgical procedures when combined with nitrous oxide or local anesthetics, or both. Adjunctive use of potent opioids (eg, fentanyl, sufentanil or remifentanil see Chapter 31) contributes to improved cardiovascular stability, enhanced sedation, and perioperative analgesia. However, opioid compounds also enhance the ventilatory depressant effects of the intravenous agents and increase postoperative emesis. Benzodiazepines (eg, midazolam, diazepam) have a slower onset and slower recovery than the barbiturates or propofol and are rarely used for induction of anesthesia. However, preanesthetic administration of benzodiazepines (eg, midazolam) can be used to provide anxiolysis, sedation, and amnesia when used as part of an inhalational, intravenous, or balanced anesthetic technique. 

Side-effects Morphine induces a variety of centrally- and peripherally-mediated side-effects. The most important of which is respiratory depression following parenteral administration, especially in the postoperative situation. Chronic oral application induces constipation and chronic treatment with oral morphine must be supplemented with laxatives. Other frequent side-effects are nausea, vomiting, dizziness and sedation. 

A 13-year-old boy underwent a 17-hour craniotomy in an attempt to resect an arteriovenous malformation with propofol-based anesthesia. He developed frank propofol infusion syndrome after 74 hours of postoperative propofol sedation in the neurosurgical ICU (used to manage intracranial hypertension). Echocardiography showed severe biventricular dysfunction despite extraordinary pharmacological support. Extracorporeal circulation with membrane oxygenation (ECMO) was instituted at the bedside via cannulation of the left femoral vessels. Hemofiltration... 

Prophylactic intravenous droperidol (10, 20, 40, or 80 micrograms/kg) dose-dependently reduced postoperative nausea and vomiting without increasing the time to discharge in 82 children who underwent strabismus surgery (5). There were no particular adverse effects, but sedation scores were higher in those who received the higher doses. 

Droperidol 0.5 micrograms reduced the need for postoperative morphine delivered via a patient-controlled analgesia device (31). At these doses it was non-sedating and caused no dyskinetic movements. 

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