Anesthesia protocols for pediatric and geriatric veterinary surgical cases

Veterinary Nursing Anesthesia and Analgesia Case Journal

The objective of this study is to address anesthesia needs in two specific cases with the first being a 12-week-old Jack Russell puppy and the second being a 12-year-old geriatric cat.

12-Week-old Jack Russell Puppy

This 12-week-old Jack Russell Puppy has eaten a babies dummy. This case study will highlight the anesthesia requirements and protocol and highlight the relevance of effect on renal function, speed of recovery, analgesia, emphasis on knowledge and understanding. Even at 12-weeks of age, this puppy is considered a pediatric patient according to the work of Gleed and Seymour (1991). This means that the patient has a higher oxygen requirement that the adult. The tongue of this patient due to his age is large and the airway is small in diameter. As well, there is a lower functional renal capacity in this age patient all of which make the patient at risk of airway closure or collapse and hypoventilation and this is especially true when influenced by respiratory depressants including volatile anesthetic agents." (Myerscough College 2011) The heart of the pediatric patient is reported as having a high percentage of "non-contractile mass, and the ventricles have low compliance" (Myerscough College 2011) Pediatric patients are not as able to tolerate loss of blood as are older patients and the hypotensive and bradycardic effects of drugs such as opioids are heightened in younger patients. The pediatric patient is prone to glycogen storage due to the liver and this results in pre-operative fasting as well as a slow return of the patient's appetite following anesthesia to occur. Due to reduced renal function, pediatric patients do not tolerate a great many liquids. Pediatric patients are also more prone to hyperthermia due to their reduced ability to thermoregulate as compared to the older patient. There should be an attempt to minimize the time the pediatric patient is under anesthesia and to simultaneously reduce loss of heat. When inhalation agents are used as the only anesthesia in pediatric patients there is a re3quirement for high concentrations and it can be assumed that this will result in depression to the cardiovascular and respiratory system of the pediatric patient. Suggested is an approach that is balanced in nature. There is a need of such as tranquilizers, injectable anesthetic agents and sedatives in lower doses and pre-anesthetic medications include a combination of opioids and benzodiazepines. Another consideration is that of anticholineragics to maintain adequate heart rate resulting in adequate cardiac output. Glycopyrrolate would be chosen over atropine and it is necessary to avoid Acepromizine and alpha-2-agonists because of their cardiac and respiratory depressive effects. It is reported that isoflurane or sevoflurane with a non-rebreathing system can be used in maintenance of anesthesia. Hypoxia can be avoided by pre-oxygenation of patients. Fluids that contain dextrose are appropriate for use in young patients and can be administered through IV. Basic fluid administrating is at the rate of 5-10m./kg/hour and a syringe driver or burette can be used to administer intra-operative fluids. The work of Bennett, et al. (2008) reports that reports a study involving 108 dogs that were admitted to the Queen's Veterinary School Hospital, University of Cambridge for various surgical and diagnostic procedures over a period of nine-months. The study investigated "sevoflurane's role as a maintenance anesthetic for clinical practice." (p.395) The study findings state as follows: "In conclusion, we found that the characteristics of sevoflurane anesthesia under clinical conditions were similar to those of isoflurane. The higher ETCO2 with sevoflurane reflected greater reduction in alveolar ventilation, but the actual differences were of limited biological significance. The higher ETsev reflected sevoflurane's lower potency. Sevoflurane appears as suitable as isoflurane for maintenance of anesthesia in canine patients undergoing a range of elective surgical and diagnostic procedures. Anticipated attributes such as a faster and smoother recovery after sevoflurane require a more appropriate protocol for specific investigation." (Bennett, et al., 2008, p.396)

7. Stress (Myerscough College 2011)

Selection of drug is based on the minimization of cardiac depression and may include drugs that have a specific reversal agent minimizing the time of anesthesia. Propofol is a drug used in elderly patients and should be used at a low dose and calculated for lean body mass. Fluid administration is focused on maintaining normal hydration, blood pressure, and renal function. It is necessary that oxygen be administered throughout the anesthetic for geriatric patients. The facility to support ventilation is advised whether this be through manual or mechanical means. Adequate analgesia is critically important and opioids have been found to be very useful. (Myerscough College 2011) The work of Grint, Burford, and Dugdale (2009) reports that Cats are more difficult "to restrain for intravenous catheter placement and induction of anesthesia than dogs because of their temperament. An ideal pre-anesthetic medicant would calm and sedate an animal, provide analgesia and muscle relaxation and reduce the dose requirements for both anesthetic induction and maintenance agents." (p.72) Opioid use in cats has been controversial in the past stated to be due to "maniacal reactions to high doses" however opioids are reported to make provision of useful analgesia in cats. Better postoperative analgesia is reported to be produced by Buprenorphine than morphine in cases of prolonged duration of analgesia. (Grint, Burford, and Dugdale, 2009, p.73) The work of Murrell (2007) reports that the aims of premedication in small animals are to "produce reliable sedation and anxiolysis" as well as to have 'minimal effects on the cardiovascular system" and to "cause minimal respiratory depression" and "produce analgesia" as well as having "reversibility." (p.100) Murrell reports that Acepromazine results in sedation and anxiolysis that "is initially dose dependent" and that an increase in the dose "within the range 0-01 to 0-05 mg/kg will generally improve sedation." (Murrell, 2007, p.101)