Anaesthesia is a common element of patient care in veterinary practice; however, it can present numerous challenges. The risks of anaesthesia are often accepted, but with pharmacological, patient and anaesthetist factors, staff must be prepared so that any potential complications can be predicted.
Veterinary nurses play a pivotal role in anaesthesia while under the direction of the veterinary surgeon. Their skills should be used to identify and resolve anaesthesia-related issues, communicate effectively and provide appropriate interventions to ensure the safety and well-being of patients.
Pre-anesthesia preparation
Complications and/or adverse events are common in veterinary anaesthesia but can be anticipated and avoided through appropriate preoperative assessment and planning. Appropriate preparation involves more than just setting up equipment, calculating dosages and drawing up drugs: preparedness, individualised patient care planning, effective communication and teamwork are essential for maximising patient outcomes during anaesthesia (de Santana Lemos and de Brito Poveda, 2019). These concepts, as well as the use of cognitive aids, can be adopted in veterinary practice to ensure safe and effective anaesthesia.
A comprehensive patient evaluation, including a thorough review of the history and physical examination, should be completed to identify any abnormalities that may indicate that an alteration in anaesthetic protocol is required. Pre-anaesthetic examinations influence the anaesthetic and analgesic agents chosen in a clinically significant proportion of cases undergoing general anaesthesia or sedation for surgical, diagnostic or imaging procedures (Louro et al., 2021). Thorough examinations prior to anaesthesia can result in the reclassification of the American Society of Anesthesiologists (ASA) physical status, which could alter the assessment of the patient’s peri-anaesthetic risk in some cases (Louro et al., 2021). The pre-anaesthetic patient evaluation is critical for patient safety as it identifies individual risk factors, underlying physiological changes and pathological compromise that may impact the anaesthetic plan (Grubb et al., 2020).
The whole surgical team should review the patient’s history, including previous anaesthetic experiences and any underlying health conditions. The importance of a vet-led team approach to anaesthesia cannot be underestimated. While the veterinary surgeon may undertake the clinical examination, the veterinary nurse monitoring the anaesthetic should be present. To reduce risks and prevent injury to the patient, planning appropriate care by a multi-professional team is paramount (Gaba, 2010). This way, all team members will be aware of what to do if complications occur.
The most common cause for preventable errors in anaesthesia is miscommunication and breakdown in teamwork
Effective communication between members of the veterinary team is a critical component of maintaining safety during the peri-anaesthetic period. The most common cause for preventable errors in anaesthesia is miscommunication and breakdown in teamwork. Preparing the entire team can reduce the likelihood of errors occurring and make anaesthesia safer (McMillan, 2016).
Anaesthetic safety checks in veterinary practice
The thorough preparation of equipment prior to induction can often be overlooked but is an essential part of a veterinary nurse’s role and crucial to improving patient safety in veterinary anaesthesia. Anaesthesia often involves the use of multiple items of equipment. Therefore, it should be foreseen that there may be equipment failure at some point. Many of the problems with anaesthetic equipment during the peri-anaesthetic period are associated with inadequate preparation, poor maintenance and a lack of knowledge of the equipment. Correct use and understanding of the function of ancillary anaesthetic equipment can benefit the patient and practice and allow for the safe delivery of anaesthetic gases while reducing the negative economic and environmental impacts (Clancy, 2023).
Many of the problems with anaesthetic equipment during the peri-anaesthetic period are associated with inadequate preparation, poor maintenance and a lack of knowledge of the equipment
The anaesthetic machine and breathing system are the most significant pieces of anaesthetic equipment, with failures often causing life-threatening complications. Anaesthetic equipment should, therefore, be considered “life-critical” because patient well-being can be adversely affected if the equipment is used incorrectly or has suboptimal function (Grubb et al., 2020). Therefore, it is vital that full machine checks are performed at the beginning of every day and before every anaesthetic procedure. A reliable way to prevent equipment failure is to inspect each part of the machine daily and before use (Matthews et al., 2017).
Anaesthetic equipment should, therefore, be considered ‘life-critical’ because patient well-being can be adversely affected if the equipment is used incorrectly or has suboptimal function
Staff undertaking anaesthesia have a responsibility to understand the proper use and function and troubleshoot all necessary equipment before use. In fact, studies suggest that staff should not attempt to use anaesthetic equipment before being properly trained to troubleshoot problems (Matthews et al., 2017). Proper staff training should also be supported with cognitive aids. Therefore, checklists for daily anaesthesia machine function, case preparation and preventative maintenance should be available.
Equipment and consumables should be gathered before anaesthesia and placed in a logical order, including equipment for intravenous catheterisation, endotracheal intubation and fluid therapy, together with monitoring devices. Drugs drawn up before induction, such as premedication, analgesics and anaesthetic induction agents, must be clearly labelled and double-checked by the surgical team. They should be kept in separate patient trays to reduce the risk of mistaking drugs. Emergency doses should be calculated but not necessarily drawn up in advance to avoid inadvertently administering the wrong drugs during the busy induction period or when distracted.
Example of equipment checks:
- Oxygen and inhalation agent levels
- Gas line connections and valve function
- Emergency oxygen button function
- Patient breathing systems, including the endotracheal tubes
- Soda-lime and scavenger system
- Patient monitoring and warming devices
- Required drugs calculated, prepared, counter-checked and labelled
- Emergency drugs pre-calculated
- Consumables set out in a logical order
The use of anaesthetic safety checklists
The ASA Physical Classification System (Figure 1; Table 1) and the Association of Veterinary Anaesthetists’ Anaesthetic Safety Checklist (Figure 2A and 2B) have been developed to help the veterinary team prepare and plan for anaesthesia. Anaesthetic checklists ensure familiarity with equipment and confirm that safety checks have been carried out. They also acknowledge that patient details have been considered and are part of the anaesthetic plan and that the risk of human error has been mitigated (Bell, 2024).
Each of the steps in the checklists has been included to reduce the risk of significant avoidable harm that can occur during the anaesthetic process. All patients should have an anaesthetic checklist to avoid mistakes and instigate final checks in preparation for induction (McMillan, 2014). While checklists are not designed to be a comprehensive list of all steps in the anaesthetic process, they are a framework to help ensure that critical safety actions are performed. According to Leape (2014), “It is not the act of ticking off a checklist that reduces complications, but [the] performance of the actions it calls for.”
| ASA classification | Description | Example |
| ASA 1 | Normal healthy patient | Healthy (non-brachycephalic) patients with no underlying disease presenting for elective procedures, for example neutering |
| ASA 2 | A patient with mild systemic disease (animal compensating well) | Brachycephalic breed considered healthy Controlled epilepsy Localised infection Obesity |
| ASA 3 | A patient with severe systemic disease (animal not compensating fully) | Brachycephalic breed with moderate/severe respiratory/gastrointestinal signs Controlled renal disease Healthy neonate (under 12 weeks old) Moderate dehydration Pyrexia |
| ASA 4 | A patient with severe systemic disease that is a constant threat to life | Cardiac murmur grade 4/6 to 6/6 Dyspnoea Severe shock Urinary obstruction |
| ASA 5 | A moribund patient who is not expected to survive without the procedure | Advanced compensated cardiac disease Disseminated intravascular coagulopathy (DIC) Gastric dilation-volvulus Multiple organ dysfunction (MODS) |
| E | The addition of the letter “E” to a grade denotes an emergency |
Troubleshooting anaesthetic complications
An immediate and effective response to complications that occur during anaesthesia is critical. Maintaining clear, accurate and detailed records of anaesthetic monitoring in the perioperative period, including drugs administered, dosages and patient responses, will allow for earlier recognition of adverse anaesthetic events.
Maintaining clear, accurate and detailed records of anaesthetic monitoring in the perioperative period, including drugs administered, dosages and patient responses, will allow for earlier recognition of adverse anaesthetic events
The most common patient complications are hypotension, hypoventilation, hypoxaemia, hypothermia and some arrhythmias, such as sinus tachycardia and bradycardia (Grubb et al.,2020). Having knowledge of the potential perioperative complications related to anaesthesia will allow for faster detection and management (Marotto et al., 2020). Recognising and understanding why abnormal monitoring parameters occur during the anaesthetic maintenance phase will allow effective troubleshooting and rectification if necessary (Dagnall, 2018).
Conclusion
Veterinary nurses are crucial in ensuring safe and effective anaesthesia through monitoring, troubleshooting and ensuring careful administration of drugs. By being vigilant, well prepared and knowledgeable about common anaesthetic issues, veterinary nurses can help mitigate the risks and enhance patient outcomes. Regular training and education on the latest anaesthetic practices are also essential to maintain high standards of care in anaesthesia.
