Anesthesia for severe liver dysfunction.

By using these guidelines, we have safely anesthetized high-risk liver patients with minimal complications. By understanding the consequences of the underlying disease, prudent selection of agents that use alternate methods of excretion, careful perioperative support and management, and close observation during the postoperative period, the liver disease patient may be safely anesthetized with minimal complications.     

Anesthesia for patients with head trauma.

Patients undergoing anesthesia soon after head trauma are at great risk for further neural damage during the anesthetic, especially if the head injury is severe or the anesthetic technique is suboptimal. Secondary complications of the anesthetic that are often lethal include hypoventilation, increases in ICP, airway obstruction, and brain-stem herniation. Anesthetic management of patients with head injury must include intravenous induction with barbiturates or narcotics, smooth endotracheal intubation, controlled ventilation with oxygen, and minimal amounts of inhalational agents. It is important to position the patient so that jugular veins are not occluded, in about 10 degrees head up position, and to avoid inducing patient coughing and straining. Recovery from anesthesia should be quiet and rapid, with the maintenance of a clear airway and the use of as little depressant medication post-operatively as possible. Oxygen should be provided.     

Anesthesia for severe mitral and tricuspid regurgitation.

Anesthesia for mitral or tricuspid regurgitation should be designed to maintain cardiac output by decreasing systemic and pulmonary vascular resistance to aortic and pulmonary outflow, respectively, and by carefully preserving venous return. A moderate increase in heart rate may be helpful with mitral regurgitation; bradycardia should be avoided. Isoflurane, halothane, or opioid anesthesia is preferred.     

Anesthesia for patients with dehydration/hypovolemia.

Anesthetic drugs normally depress cardiovascular function and in a patient that is already dehydrated and hypovolemic can cause severe hypotension. Reestablishing intravascular volume with a balanced salt solution can return cardiovascular function to normal, and anesthesia must not be induced until the animal has been stabilized.     

Anesthesia for geriatric patients.

Choosing the best anesthetic agents for each geriatric animal does not in itself ensure a successful outcome. Aggressive, careful, vigilant monitoring during the anesthetic and recovery periods is required to detect and correct alterations in homeostasis that may develop during the perianesthetic period. With appropriate preoperative screening, informed choice and judicious dosing of anesthetics, and careful monitoring and supportive care, the risk of anesthesia in geriatric animals can be greatly reduced.     

Anesthesia for patients with stable end-stage renal disease.

Patients with stable, end-state renal disease should be premedicated with an opioid and induced with minimal doses of an ultrashort barbiturate or isoflurane. Supplemental systemic or epidural analgesics can be administered if necessary. Urine output should be monitored in the perioperative period. If oliguria exists, fluids and perhaps a diuretic such as furosemide, mannitol, or dopamine should be administered.     

Isoflurane Anesthesia for Equine Colic Surgery Comparison with Halothane Anesthesia

Isoflurane was compared with halothane as an anesthetic agent for emergency colic surgery in a series of 38 juvenile and adult horses. After presurgical stabilization with fluids and supportive medications, anesthesia was induced by intravenous xylazine and/or diazepam followed by ketamine. Anesthesia was maintained with isoflurane or halothane in oxygen with controlled ventilation. Heart rates (HR), arterial blood gases, mean arterial pressures (MAP), rate pressure products (RPP), requirements for cardiovascular support medications, and recovery times to standing were compared using nonparametric methods. Cardiopulmonary responses to isoflurane and halothane anesthesia were generally comparable although some temporal differences were observed. Higher HR (p less than 0.02) and lower PaCO2 levels (p less than 0.01) were identified during the course of isoflurane anesthesia. Recovery times to standing were significantly shorter (0.02 less than p less than 0.05) after isoflurane than halothane anesthesia.     

Anesthesia for cesarean section in the dog.

At the time of cesarean section, the mother may suffer respiratory depression, hypotension, increased gastric acidity, and increased predisposition to regurgitation, and the newborn may suffer anesthetic-induced respiratory depression. Preanesthetic metaclopramide, cimetidine, and anticholinergic agent are recommended. Sedatives can be administered if necessary. Neuroleptanalgesic and low-dose general anesthetic, with local anesthetic line-blocks, are preferred techniques. Supportive care of the newborn is mandatory.