2 (α2) adrenergic agonists, such as dexmedetomidine, bind central α2 receptors to result in sedation, muscle relaxation, and analgesia. Additional effects include vasoconstriction, reflex bradycardia, and diuresis. Dexmedetomidine should be used cautiously in critically ill patients and should be reserved only for patients without cardiovascular disease or compromise. At low doses (1–5 μg/kg IV), dexmedetomidine is synergistic with opioids for analgesia and can be used as a bolus or CRI. Its effects can be reversed with the α2 receptor antagonist atipamezole. The volume of atipamezole used for reversal is the same volume as the administered dexmedetomidine. Intramuscular administration of atipamezole is preferred to prevent rapid drug reversal, which can cause hypotension or aggression [102–104].
Benzodiazepines are effective for mild sedation and anxiolysis with minimal cardiovascular compromise. They are commonly combined with opioids for analgesia and sedation and can decrease the dose of opioids needed to achieve the desired effect. Midazolam and diazepam can be given intravenously, but only midazolam can be given intramuscularly and is preferred for CRI therapy due to the propylene glycol vehicle of diazepam. Reversal of both agents can be accomplished with intravenous dosing of flumazenil.
Phenothiazines, such as acepromazine, provide no analgesia but are potent anxiolytics in veterinary medicine. They must be used cautiously in cardiovascularly unstable patients as they can cause profound vasodilation and hypotension. They are especially useful in patients with respiratory distress, particularly upper airway obstruction. However, intravenous acepromazine takes approximately 15 minutes to achieve maximal effect, so this delay in onset of action should be anticipated in patients [101]. This is important in patients in respiratory distress, for whom this delay may not be tolerated, and more rapidly acting medications should be selected.
Non‐steroidal anti‐inflammatory drugs (NSAIDs) have a limited role in treating pain and inflammation in many emergency patients, especially those with gastrointestinal and renal disease or cardiovascular compromise. Even NSAIDs that can be administered parenterally should be used with extreme caution in patients with perfusion abnormalities, as they can increase the risk of gastrointestinal ulceration, hepatic insult, and kidney injury. NSAIDs are generally not recommended for cats, unless given as a single dose in healthy, hydrated, and normovolemic cats. An NSAID designed for safer use in cats (robenacoxib) is available, but extensive clinical experience is lacking. However, postoperatively, when perfusion is restored and normalized, many surgical patients benefit from control of inflammation and the analgesia achieved with NSAID therapy.
2 Operating Room Nursing Tips for Emergency Surgical Procedures
Cami Elliott1, Michelle Capps2, and Michael McCallum2
1 Nashville Veterinary Specialists and Animal Emergency, Nashville, TN, USA
2 University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA, USA
Gastrointestinal System
Most gastrointestinal procedures can be performed with routine instruments, with a few additional items supplied as needed. It may be beneficial to establish a routine soft tissue instrument set, such as the one listed in Box 2.1.
Unless otherwise noted, patients will be placed in dorsal recumbency for gastrointestinal surgeries. It is also of benefit to have a variety of sizes of containers and formalin available for biopsies taken during gastrointestinal surgery.
Esophageal Surgery
A lodged esophageal foreign body is the most common indication for esophageal surgery and the location of the foreign body will determine the approach. The cervical esophagus is exposed through a ventral midline approach and the thoracic esophagus is approached via a lateral thoracotomy. Recommended instruments will depend on the approach chosen and are listed in Box 2.2.
Gastrointestinal Foreign Bodies
When preparing the operating room for a gastric or intestinal foreign body surgery the technician should keep in mind that a gastrotomy, enterotomy, or intestinal resection and anastomosis could be performed. To prepare for these events, consider that preventing the spillage of ingesta into the abdominal cavity is of key concern. Sterile lap sponges, lavage, and suction are crucial in preventing contamination and peritonitis. Portable suction machines are available if the operating room is not equipped with wall suction (Box 2.2, Figures 2.1 and 2.2).
Rectal Prolapse
A prolapsed rectum can be reduced and retained in its normal position by applying a purse‐string suture around the circumference of the anus. Nylon suture (3‐0) on a straight needle is ideal for this purpose. Prior to reducing the prolapse, white granulated sugar can be applied to the prolapsed tissue to alleviate some of the tissue edema. A routine soft tissue instrument set should be sufficient, with the addition of a culturette due to the location of the surgery and concern for contamination. The patient is positioned in sternal recumbency in Trendelenburg position if the surgery table tilts. Alternatively, a rectal stand to elevate the caudal end of the patient to approximately shoulder level of the surgeon can be used.
Hemoabdomen
When preparing an operating room for a patient with a hemoabdomen, the first step upon entering the abdomen will be to remove the accumulated blood to visualize the source of hemorrhage. See Figure 2.1 for suction and lavage instrumentation. In addition to the routine soft tissue instrument set, sterile suction tubing to connect to wall‐mounted or portable suction and additional suction canisters should be available, depending on the volume of fluid to be removed. A Balfour retractor will be helpful for abdominal wall retraction while the surgeon completes a thorough examination of the abdomen to identify the source of hemorrhage. Monopolar cautery and a bipolar vessel‐sealing device (LigaSure™) are helpful in controlling hemorrhage and expediting the surgical procedure.
Box 2.1 Routine Soft Tissue Instrument Set
3 straight and 1 curved carmalt forceps
4 Allis tissue forceps
8 Kelley forceps
6 mosquito forceps
4 large Backhaus towel clamps
10 small Backhaus towel clamps
2 needle drivers
Poole suction tip
2 Army Navy retractors
2 Parker retractors
2 basins
#3, #4 scalpel handles
Debakey
