Anesthetic considerations for the geriatric patient

The geriatric patient presents an anesthetic challenge due to the physiologic alterations that occur during aging. The geriatric patient usually has an increased number of disease processes and does not possess the functional organ reserve capabilities compared to a younger patient. The geriatric patient seems more susceptible to the cardiopulmonary depressant effects of the preanesthetic and anesthetic agents in common use and, due to decreased hepatic function and other factors, may have a delayed recovery from these drugs. The preanesthetic and anesthetic drugs chosen for a geriatric patient will depend on that particular patient's physiologic status, the procedure to be done, and the experience of the veterinarian. Adequate fluid and monitoring support should always be provided for the geriatric patient.     

Cesarean section. Anesthetic management and surgical technique

Cesarean section can be an elective procedure but more often it is an emergency procedure that is made necessary because of dystocia. A successful outcome for both the maternal and fetal patients is primarily dependent on a thorough understanding of the physiologic alterations during normal and abnormal pregnancy and parturition. A complete history and physical examination are necessary for assessment of the dam and planning of fluid therapy and anesthetic technique. Timely coordination of presurgical preparation, anesthesia, and the surgical procedure is crucial. Because little documentation exists to prove that any one anesthetic protocol is best, this article will stress the basic principles of obstetrical anesthesia and patient management.     

Pharmacists in veterinary education: bridging the gap

Veterinary patients stand to benefit greatly from the collaboration of pharmacy and veterinary medicine, and there are many ways pharmacy and veterinary medicine can work in concert. The best efforts to revise and remodel veterinary and pharmacy education to fit an evolving world of clinical practice are grounded in an understanding of each profession. Veterinary education should impart to its students and residents the skills necessary to critically evaluate drug therapy, select therapies based on facts from drug information sources, and operate a veterinary practice that abides by the legal, regulatory, and operational requirements necessary to maintain and dispense drugs. The academic training environment of each profession must include information on the other, in order to better prepare professionals for a realistic practice environment. When armed with an understanding of what pharmacists can provide their patients, veterinarians can demand these skills where appropriate. With the ultimate goal of producing an optimal learning environment, veterinary curricula should allow both pharmacy and veterinary medicine to work together to build a path to quality patient care and educational superiority.     

Anesthetic management of ruminants and swine with selected pathophysiologic alterations

Surgical diseases induce pathophysiologic alterations in ruminants and swine that are often of critical importance in the perioperative period. Circulation and ventilation may be severely compromised. Alterations in acid-base balance, fluids, and electrolytes should be anticipated, identified, and corrected. Also discussed is the selection of appropriate anesthetic techniques and supportive therapy based upon the patient's physiologic status and surgical requirements.     

Evaluation of the effects of hospital visit stress on physiologic parameters in the cat

Physiologic parameters such as blood pressure, rectal temperature, heart rate, and respiratory rate are an important part of the medical assessment of a patient. However, these factors can potentially be affected by stress. The purpose of this study was to compare physiologic parameter data gathered from cats in the home environment with those gathered in a veterinary hospital. Thirty healthy cats were evaluated both at home and at Colorado State University's Veterinary Medical Center. Doppler systolic blood pressure, temperature, heart rate, and respiratory rate were recorded, and the differences between the values obtained in the home and veterinary clinic environments were evaluated using the Wilcoxon sign rank test. A significant difference was found in blood pressure, heart rate, and respiratory rate between the home and veterinary hospital environments. This information may help practitioners recognize that physiologic abnormalities can sometimes be due to transportation or environmental stress rather than medical illness.     

Assistive devices, orthotics, and prosthetics.

Deciding on which supportive device, orthotic, or prosthetic is best suited for a given patient is a complex process involving many different factors. The ability to manage biomechanical abnormalities successfully may be enhanced by an understanding of the properties of the various materials that comprise these devices, their effect on functional performance, and other associated patient factors. Veterinary health care providers are faced with the challenge of effectively addressing the physiologic and fiscal needs of the patient in a rapidly changing patient care environment.     

Comparative cardiovascular and pulmonary effects of sedatives and anesthetic agents and anesthetic drug selection for the trauma patient

Objective: To integrate and compare the effects of tranquilizer/sedatives and anesthetic drugs on various parameters of cardiovascular function in normal dogs and in dogs stressed by hypovolemia, anemia, and endotoxemia, and to discuss the relative merits and appropriate precautions of anesthetic drugs with respect to specific patient physiologic complications. Data sources: Personal data and experiences in conjunction with veterinary and human clinical and research studies. Human and veterinary data synthesis: Drugs that produce calming, sedation, muscle relaxation, analgesia, and loss of consciousness have the potential to produce marked cardiorespiratory effects particularly in hemorrhaged, hypovolemic‐traumatized animals. Acute but key cardiovascular components that are affected by sedative and anesthetic drugs include heart rate and rhythm, venous return (preload), systemic vascular resistance (afterload), and myocardial contractile (inotropic) and relaxation (lusitropic) properties. In addition, all sedative and anesthetic drugs alter or depress normal baroreceptor reflex activity, thereby inhibiting or eliminating the animal's normal physiologic response to decreases in arterial blood pressure and predisposing to tissue hypoperfusion, decreased oxygen delivery, and oxygenation. Oxygen delivery needs to be adequate to meet the metabolic (oxygen) requirements of the patient. Decreases in oxygen delivery to tissues increases oxygen extraction, thereby maintaining tissue oxygenation (supply‐independent oxygen consumption phase) until compensatory processes reach their limit and any further decrease in oxygen delivery causes a decrease in oxygen consumption (supply‐dependent oxygen consumption phase). The critical oxygen delivery that defines the transition between these 2 phases is generally higher in the anesthetized state than in the awake state. The effect of anesthetics on critical oxygen delivery at comparable anesthetic dosages is pentobarbital=ketamine>alfentanil>etomidate=propofol>inhalational anesthetics. Anesthetics generally decrease oxygen consumption from the awake, baseline state; exceptions are ketamine and ether. Ketamine, however, increases oxygen delivery and oxygen extraction. Conclusions: The transition from the awake to the anesthetized state is a huge imposition on the physiology of animals and, therefore, should be accomplished with great care and proper vigilance. Rapid, ‘crash’ induction of anesthesia should be avoided in hypotension‐prone animals and slow, prolonged induction should be avoided in animals with respiratory disorders. It is not recommended to implement an unfamiliar protocol in critical patients, even if it might be pharmacologically preferable. Familiarity with an anesthetic drug is a very important reason for its selection.     

Coagulopathy of the critically ill equine patient

Objective – To review the hemostasis literature relevant to development of coagulopathy in the critically ill equine patient.
Data Source – Original scientific and review articles.
Human Data Synthesis – Inflammation plays a critical role in the activation and amplification of clot formation, as well as the impairment of physiologic anticoagulant mechanisms, and fibrinolysis. Earlier identification of coagulopathy in patients at risk and restoration of physiologic hemostasis may result in better outcome. Development of scoring systems based on information other than coagulation markers alone may better identify patients with subclinical coagulopathy.
Veterinary Data Synthesis – Critically ill equine patients commonly at risk for coagulopathy include those with severe gastrointestinal disease, septic foals, and adults subjected to severe systemic inflammatory response syndrome. Publications provide information regarding coagulation markers helpful for identification of hemostatic dysfunction in specific patient populations, as well as information regarding the influence of coagulopathy on outcome. Data regarding clinically relevant information on therapeutic intervention are lacking.
Conclusions – The relationship between inflammation and endotoxemia and development of coagulopathy is better understood in both human patients and the critically ill equine patient. Prospective clinical trials evaluating clinically relevant and financially feasible approaches to treatment are still needed.     

Anesthesia in ophthalmic surgery

Ophthalmic surgical patients can be routinely anesthetized without complications if the surgeon has a thorough understanding of the effects of anesthetic agents on ocular physiology. The regulation of intraocular pressure is important for successful ophthalmic surgery and can be greatly affected by the anesthetic procedure. Agents utilized to intentionally decrease intraocular pressure are often employed for intraocular procedures. These agents have profound systemic effects that must be anticipated. Adverse drug interactions between sympathomimetic mydriatics and halogenated inhalation anesthetics also must be considered.     

Information technology in veterinary pharmacology instruction

Veterinary clinical pharmacology encompasses all interactions between drugs and animals and applies basic and clinical knowledge to improve rational drug use and patient outcomes. Veterinary pharmacology instructors set educational goals and objectives that, when mastered by students, lead to improved animal health. The special needs of pharmacology instruction include establishing a functional interface between basic and clinical knowledge, managing a large quantity of information, and mastering quantitative skills essential to successful drug administration and analysis of drug action. In the present study, a survey was conducted to determine the extent to which veterinary pharmacology instructors utilize information technology (IT) in their teaching. Several IT categories were investigated, including Web-based instructional aids, stand-alone pharmacology software, interactive videoconferencing, databases, personal digital assistants (PDAs), and e-book applications. Currently IT plays a largely ancillary role in pharmacology instruction. IT use is being expanded primarily through the efforts of two veterinary professional pharmacology groups, the American College of Veterinary Clinical Pharmacology (ACVCP) and the American Academy of Veterinary Pharmacology and Therapeutics (AAVPT). The long-term outcome of improved IT use in pharmacology instruction should be to support the larger educational mission of active learning and problem solving. Creation of high-quality IT resources that promote this goal has the potential to improve veterinary pharmacology instruction within and across institutions.     

Nosocomial infections and antimicrobial resistance in critical care medicine

Objective: To review the human and companion animal veterinary literature on nosocomial infections and antimicrobial drug resistance as they pertain to the critically ill patient. Data sources: Data from human and veterinary sources were reviewed using PubMed and CAB. Human data synthesis: There is a large amount of published data on nosocomially‐acquired bloodstream infections, pneumonia, urinary tract infections and surgical site infections, and strategies to minimize the frequency of these infections, in human medicine. Nosocomial infections caused by multi‐drug‐resistant (MDR) pathogens are a leading cause of increased patient morbidity and mortality, medical treatment costs, and prolonged hospital stay. Epidemiology and risk factor analyses have shown that the major risk factor for the development of antimicrobial resistance in critically ill human patients is heavy antibiotic usage. Veterinary data synthesis: There is a paucity of information on the development of antimicrobial drug resistance and nosocomially‐acquired infections in critically ill small animal veterinary patients. Mechanisms of antimicrobial drug resistance are universal, although the selection effects created by antibiotic usage may be less significant in veterinary patients. Future studies on the development of antimicrobial drug resistance in critically ill animals may benefit from research that has been conducted in humans. Conclusions: Antimicrobial use in critically ill patients selects for antimicrobial drug resistance and MDR nosocomial pathogens. The choice of antimicrobials should be prudent and based on regular surveillance studies and accurate microbiological diagnostics. Antimicrobial drug resistance is becoming an increasing problem in veterinary medicine, particularly in the critical care setting, and institution‐specific strategies should be developed to prevent the emergence of MDR infections. The collation of data from tertiary‐care veterinary hospitals may identify trends in antimicrobial drug resistance patterns in nosocomial pathogens and aid in formulating guidelines for antimicrobial use.     

Anesthesia for the acute abdomen patient

Patients with acute abdomen often have marked physiologic and pathologic changes, making anesthesia both challenging and potentially hazardous for the patient. A thorough understanding of the pathophysiologic mechanisms of cardiovascular function under anesthesia and selection of appropriate anesthetic protocols are critical to a successful anesthetic outcome. The goal is to produce anesthesia while minimizing depression of the cardiovascular system. Monitoring and management of acid-base and cardiovascular function serve to ensure appropriate oxygen delivery to the tissues during anesthesia. Postoperative management can significantly influence patient outcome following anesthesic recovery, and must therefore be considered in the anesthetic plan. Finally, pain management in all patients is an important aspect of case management, and should not be overlooked. This article serves to educate the clinician in the above-described areas in regard to the acute abdomen patient.     

The use of intravenous lipid emulsion as an antidote in veterinary toxicology

Objective – To review the use of IV lipid emulsion (ILE) for the treatment of toxicities related to fat‐soluble agents; evaluate current human and veterinary literature; and to provide proposed guidelines for the use of this emerging therapy in veterinary medicine and toxicology. Data Sources – Human and veterinary medical literature. Human Data Synthesis – Human data are composed mostly of case reports describing the response to treatment with ILE as variant from mild improvement to complete resolution of clinical signs, which is suspected to be due to the variability of lipid solubility of the drugs. The use of ILE therapy has been advocated as an antidote in cases of local anesthetic and other lipophilic drug toxicoses, particularly in the face of cardiopulmonary arrest and unsuccessful cardiopulmonary cerebral resuscitation. Veterinary Data Synthesis – The use of ILE therapy in veterinary medicine has recently been advocated by animal poison control centers for toxicoses associated with fat‐soluble agents, but there are only few clinical reports documenting successful use of this therapy. Evidence for the use of ILE in both human and veterinary medicine is composed primarily from experimental animal data. Conclusions – The use of ILE appears to be a safe therapy for the poisoned animal patient, but is warranted only with certain toxicoses. Adverse events associated with ILE in veterinary medicine are rare and anecdotal. Standard resuscitation protocols should be exhausted before considering this therapy and the potential side effects should be evaluated before administration of ILE as a potential antidote in cases of lipophilic drug toxicoses. Further research is waranted.     

Anesthesia and pain control

Successful anesthetic management of the critically ill patient requires familiarity with the pharmacologic properties of a variety of anesthetic drugs. An understanding of the altered physiology present in the critically ill allows an anesthetic regimen to be selected that prevents an anesthetic-induced decompensation. Pain should never go untreated because of a fear of causing excessive physiologic depression. There are numerous options available to control pain. A technique suitable in one instance may be unsuitable in another; for example, an animal that has a significant degree of respiratory compromise may not tolerate the additional respiratory insult associated with narcotic use. A local anesthetic technique may be preferred in this situation. Often a local technique is all that is necessary to control postoperative pain. Furthermore, if pain is controlled for the first 4 to 6 h post-insult, often no further analgesic drugs need to be administered.     

Fluid therapy: options and rational administration.

Fluid administration is a primary component of therapy in many small animal patients. Several different classes of fluid may be given, and there are multiple options within each class. The type, route, volume, and rate of fluid administered should be tailored to the patient's signalment, disease or injury state, and response to the administration of fluids. Monitoring vital parameters and bedside monitoring of laboratory variables allow assessment of fluid therapy success or failure. Successful fluid administration also requires that parenteral fluid therapy ultimately be discontinued with minimal adverse effects for the patient.     

The immune response to anesthesia: Part 1

ObjectiveTo review the immune response to anesthesia including mechanical ventilation, inhaled anesthetic gases, and injectable anesthetics and sedatives.Study designReview.Methods and databasesMultiple literature searches were performed using PubMed and Google Scholar from spring 2012 through fall 2013. Relevant anesthetic and immune terms were used to search databases without year published or species constraints. The online database for Veterinary Anaesthesia and Analgesia and the Journal of Veterinary Emergency and Critical Care were searched by issue starting in 2000 for relevant articles.ConclusionRecent research data indicate that commonly used volatile anesthetic agents, such as isoflurane and sevoflurane, may have a protective effect on vital organs. With the lung as the target organ, protection using an appropriate anesthetic protocol may be possible during direct pulmonary insults, including mechanical ventilation, and during systemic disease processes, such as endotoxemia, generalized sepsis, and ischemia-reperfusion injury.     

Sedation and chemical restraint in the dog and cat

Small animal patients must often undergo veterinary procedures that are painful or distressful, for which judicious use of sedatives or other agents with anesthetic or analgesic properties can be useful. If the degree of sedation is profound enough, such "chemical restraint" may be employed to provide immobilization for radiographs or minor surgical procedures. The choice of agents to be used will depend upon the physiologic state and cooperative nature of the patient and the desired endpoint, ie, anxiolysis versus deep sedation with analgesia. This report discusses important features of patient assessment, preparation, equipment needs, consideration of the types of procedures for which sedation is useful, and recovery considerations. A brief review is included of the useful effects and contraindications for the various agents employed, and doses for each are listed. Algorithms are presented for a given category of patient, leading the practitioner through a decision making strategy to arrive at examples of sedation or chemical restraint protocols that are commonly found to be effective by the author.     

Preventing and managing complications of enteral nutritional support

Complications of enteral nutritional support include mechanical problems related to the feeding device, gastrointestinal side effects, metabolic disturbances, and infectious complications. Although the sickest patients are often the ones that we feel will most likely benefit from nutritional support, they are generally more challenging to feed and least likely to tolerate complications arising from assisted feeding. Many of the problems that can occur with enteral nutritional support can be anticipated, which may allow them to be avoided or possibly aid in early detection and thereby minimize consequences to the patient. Therefore, knowledge of the types of complications that can occur with enteral nutritional support will aid in the process of deciding whether and how a patient should receive assisted feeding, and what parameters to monitor while a patient is receiving nutritional support.     

Route of nutrient delivery

Nutritional intervention early in the course of critical illness in humans and animals can have a significant impact on morbidity and mortality. Enteral delivery of nutrients is less technically demanding, more physiologic, and less expensive than parenteral nutrition. Furthermore, as complete bowel rest during critical illness can be associated with detrimental intestinal structural and functional changes ultimately resulting in bacterial translocation from the gut, direct delivery of nutrients to the gastrointestinal tract is preferred in patients with sufficient gastrointestinal function to allow digestion and absorption of nutrients. Once the decision to "feed the gut" has been established, there are several routes of enteral nutrient delivery available. A sound knowledge of gastrointestinal function, anticipated duration of enteral support, and co-moribund conditions will help the clinician tailor a plan of nutrient delivery that optimally meets each patient's needs. This article will review available routes of nutrient delivery to the gastrointestinal tract, and discuss indications and contraindications for each.     

Feline anesthetic deaths in veterinary practice

Anesthetic complications appear relatively rare, though recent work suggests they are more common in cats than dogs. Current estimates indicate that approximately 0.11% (1 in 895 anesthetics) of healthy cats die of an anesthetic-related death, which is more than twice as frequent as has been recently reported in dogs (0.05% or 1 in 1849). Most of these deaths occurred in the postoperative period. A number of risk factors have been associated with death, including patient health status, age, weight, and procedure type and urgency. Endotracheal intubation and fluid therapy have been reported to be associated with increased odds of anesthetic death in cats and may reflect higher risk techniques in cats compared with dogs. Monitoring patient pulse and the use of a pulse oximeter were also recently reported to be associated with reduced risk of anesthetic death. These data can help veterinarians care for their patient under anesthesia and address greater attention to patient assessment and management before anesthesia, as well as more careful fluid administration and patient monitoring during and after anesthesia, which could reduce perioperative complications in cats.