Thank you, Sophie. Thank you for your kind introduction. Just to let you know, I'm not working in bath referrals anymore.
I'm working in Highcroft, the veterinary referrals in Bristol. That's fine and welcome to these webinars tonight and thank you very much for joining, tonight. Now then, the focus of tonight's webinar will be small mammal anaesthesia and the aim of the, the webinar will be to to see.
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So the aim of tonight's webinar will be to go through the reasons why we find the anaesthetizing small mammals so challenging, and we'll see how we can minimise the risk of anaesthetizing small mammals trying to increase, you know, the chances of a more positive outcome. Now, according to relatively recent study, the per anaesthetic mortality rate in small mammals is about 5 to 10 times higher as compared to dogs and cats. So why this is these numbers are so high.
And consider that these piping so high, they're actually much, much lower as compared to studies about 20 years ago when the mortality rate reported for rabbits, for example, was 1 in 28 rabbits. So the reasons are quite a few. Now first of all, small mammals and in particular pet rodent species, for example, are prey species, meaning that they are masters of disguising signs of disease that they're often presented in advanced state of illness, meaning that the obviously the per anaesthetic risks are much higher.
They also become very easily stressed, for example, when handled, when brought out of their routine environment or you know, obviously in an unfamiliar space, they have a higher metabolic rate, meaning that obviously their smaller glycogen reserves lead them very, very easily to hypoglycemia, but also means that drug metabolism may be completely. Different to us compared to different species of drugs may be metabolised much faster, maybe excreting much faster as compared to dogs and cats, and that's why it's often obvious to directly extrapolate drug dosages from other species. It also means that certain drugs may have a shorter duration of actions in this case compared to dogs and cats, so it is always useful to check.
Exotic formularies, for example, or specialised forms or textbooks to check if there have been reported pharmacokinetic and pharmacodynamic studies or at least anecdotal or dosages for the drugs that you're going to use. Now higher metabolic rates also means higher oxygen consumption, meaning that you know, these may lead to consequences when a certain things occur during an anaesthetic. This coupled with the fact that they have a very small thoracic size.
Compared to their body mass may lead them to anaesthetic complication much easier as compared to another species. The complications occur not just more easily but also much faster, meaning that in the majority of cases we have a shorter time for intervention when Problems occur. So we'll see how we can try and reduce these these problems to make our anaesthetic not just a little bit easier for us but also obviously safer for these patients.
Now often general anaesthesia and sedation are used interchangeably. However, there is a major difference between these two concepts. Now, general anaesthesia may be considered as a drug induced reversible state of muscle mass relaxation, amnesia.
Loss of a response to noxious stimuli, for example. So as as a general, more simply with loss of consciousness. On the other hand, the sedation is simply a depression of consciousness, obviously drug induced.
So the main difference between general anaesthesia and sedation is That a general anaesthetized animal is achieving a surgical plane of anaesthesia, whereas a sedated animal does not. Obviously there are different levels of sedation that can be achieved in the majority of cases, sedation that can be considered safer as compared to a general anaesthetic because The drugs that are used are generally used at lower doses, for example, or the cocktail is different as compared to that that induces a general anaesthetic and in the majority of cases theses that prevents worsening of underlying clinical conditions, for example, and promotes in some ways a cardiovascular stability. However, sedation is not completely devoid of of.
Risks and needs to be done with extreme caution because between sedation and general anaesthesia, sometimes there is a fine line and it is important also to remember that sedation can allow, for example, handling can reduce stress, can allow minimal or minor diagnostic procedures such as taking X-rays or in some cases collecting a blood sample. However, the animal remains . You know, deeply, responsive in the sense that the animal can be aroused very easily by subjecting it to a painful stimulus.
So this is always important to remember. And it's also important to remember that sedation can be reversed into a general anaesthetic state by obviously in by using obviously further drugs or increasing the dose of the drugs that have already been used. Now it is important to remember that the concept of balanced anaesthesia, which is obviously nothing specific to small mammals but can be extrapolated directly from dogs and cats and which implies you know, the same element of an anaesthesia such as unconsciousness, amnesia, immobility, muscle relaxation, a reduced autonomic response to noxious.
Stimuli, but using, let's put it this way, a cocktail of drugs at a lower overall doses. Now the importance of this concept is probably even more applicable to small mammals than in dogs and cats because obviously in many cases these animals are at increased risk using. Multiple drugs but are lower.
Overall dosages actually reduces the the side effects of each of these drugs, eventually promoting aerodynamic stability and reduces the overall risks of the anaesthetic itself. However, it is always important to remember that whatever we do, morbidity and mortality during an anaesthetic increase with the length of the anaesthetic itself. And that's why it's extremely important to be prepared, to prepare the animal, obviously, to prepare the equipment to prepare the drug, so to make sure that everything is ready for that certain procedure to be performed so that once the animal is actually anaesthetized, we don't waste time looking for things, for example, which may prolong unnecessarily the length of the anaesthetic itself.
But obviously we'll go through each of these aspects later on during the presentation. Now for what concerns the the patient, for example, it is important to remember that as we said, many of these patients are prey species. They can get very easily stressed when handled, when separated from their companion, for example.
So it is important to use an adequate handling technique for the species that obviously we are taking into consideration whether it is a guinea pig, a chinchilla, a mouse, a hamster, or a dago. Also, taking into consideration specific, anatomic, features of some of these species. For example, degus and gerbils should be handled with extreme care because of the risk of TLD globin injuries, and, some of these patients.
Also can inflict quite a painful bite. So it is important to always take this into consideration. It is obviously a general concept, not just aimed at a general anaesthetic, but it is extremely important to remind this.
And the other, the other thing to remember is chinchillas. Chinchillas, when handled, can lose patches of fur, but in some cases this first sleep is actually quite severe with the fur not regrowing for several weeks. And the other species that needs to be handled with extreme care is hamsters.
Obviously, scruffing with, too much aggression can cause proctosis of the osis. So this is extremely important to consider. Now, as we said, it is important to get ready for a general anaesthetic, and this is in terms of the patient first of all, as we said, being prey species, rodents in particular, small mammals in general, tend to hide the signs of diseases.
So it is important once they get for a pre-anesthetic checkup to get as many information as possible from the owner. So a detailed history is extremely important because in many of these cases. Is an inappropriate husbandry management or diet may predispose them to diseases, so it is important to pick up those aspects of the husbandry which may predispose to certain conditions which may ultimately increase an anaesthetic risk.
Now, a pre-anesthetic evaluation also implies a complete physical examination. Many of these animals can be handled adequately to allow a complete physical examination. For many others, unfortunately, a complete physical examination may be performed only with the animal under anaesthetic.
However, as many information as possible from the physical examination should be collected and never forget to detect the weight to record the weight of the animal, not just because the weight is very important to monitor also the health status of a patient. If there is no indication whether that patient is actually eating or not, weight loss may be an indication of an underlying clinical condition, but also it is very important to calculate drug dosages. In many cases, dilution.
May be required, so it is important to have an accurate weight determination for the patient to be for an anaesthetic and we'll see how this is important also when when determining the dosages of emergency drugs because we are talking in terms of 0.00 dosages. So it is important to have an accurate weight in these cases.
Now, a physical examination is also very important to collect the baseline parameters such as heart rate, respiratory rate, and body temperatures. Now there are out there many textbooks that report reference ranges of physiologic parameters, but obviously they are textbook. It means that obviously they are not our patient.
Pre-anesthetic evaluation in terms of Physical examination allow us to determine the reference range for that specific specific patient. So those reference ranges that also will be our baseline parameters from which we will start at the beginning of the anaesthetic, which we will monitor throughout the anaesthetic and which we aim to return at the end of the anaesthetic procedure. So a physical exam examination is actually extremely useful throughout the per anaesthetic period.
Now, as we said, it is important to get the patient ready before an anaesthetic itself. Now, in many of these patients, unfortunately collecting a pre-anesthetic blood blood panel is is difficult because collecting a blood sample actually requires an anaesthetic itself. However, a short general anaesthetic or sedation may may be.
Sufficient to collect a small amount of blood which may give us a lot of information in terms of then undergoing a more prolonged general anaesthetic, so collecting pre-anesthetic parameters including liver and kidney values, for example, may be of extreme importance in terms of of a general anaesthetic if possible. Now whenever possible, debilitated patients should be stabilised. Consider that compensatory mechanisms are blunted during an anaesthetic.
Therefore, hypothermia, hypoglycemia, dehydration, anaemia may worsen throughout an anaesthetic and therefore it is important whenever possible to correct these abnormalities before the animal is anaesthetized. Also, whenever possible, administer analgesics before a painful stimulus is applied, and this may be done using different drugs such as non-steroidal, for example, or combination of non-steroidal and opioids and a combination of local anaesthetics as well. So it is important to evaluate whether the animal requires preemptive medications as well.
And as we said, preparation also means emergency preparation, so get ready for the worst, even if that doesn't happen, but it is important to get ready emergency drugs or pre-calculate the drugs in case of an emergency because consider the majority of these drugs will actually result in minimal volume, requiring some cases a dilution that in cases of an emergency cannot be. Done in an extremely short period of time and whenever possible place an an intravenous or an intrusive cat. So as I always say, preparation is definitely a key for success because it actually allow us to get ready to be prepared in case of a problem, to detect problems at an early stage and therefore act promptly.
Now, as we said, it is important whenever possible to place an intravenous cathedral at least whenever a small mammal is going to be anaesthetized. Nowuscular axis is extremely important because it allows us to deliver anaesthetic and emergency drugs, enables a rapid response in case of emergencies. It also represents a very efficient route to administer replacement fluids throughout.
The anaesthetic period and in the recovery phase and also provide options for post anaesthetic nursing management, as we said. Now, intraosseous catheter placement can be extremely easy in this species and can in some cases make the difference, because it allows obviously an alternative to an intravascular catheter whenever this is not possible, is not possible to be placed. In terms of fasting, there is a lot of debate about this.
However, in the majority of cases, rodents as well as rabbits are not fasted for a prolonged period of time, and at least overnight fasting is never recommended. The reasons are different now. The majority of those That suggest a short, a shorter fasting suggested that the reason for this may be in the fact that with a short fasting we reduce the the volume of the stomach ultimately pressing on the diaphragm which potentially may result in compromised respiration.
However, if you consider that, you know, the, the stomach of the majority of these small mammal is never empty, even after 24 hours fasting in reality, reducing the, the stomach content with just, you know, a couple of hours fasting is, is not possible. So what we can do is actually to, to provide or continue providing definitely hay and always water but simply remove vegetable and let's say for about 30 minutes. It's before the anaesthetic is started, always remember to clear the mouth from food and other material, especially if you have animals such as ants that have got cheek pouches.
Also important to remember that positioning, and we will see that later on, is extremely important during an anaesthetic because it can actually help reducing the impact that the largest stomach may have on the small thoracic cavity. So adopting what is called the anti-trendel. Position with the chest is slightly elevated as compared to the abdomen may be extremely useful.
Always remember as well that as small mammals have a high metabolic rate, their glycogen reserves are actually quite small, so prolonged fasting may also induce hypoglycemia and further complicate the anaesthetic itself, especially if the animal were anorexic before starting the the anaesthetic. Now we already discussed about preparation in terms of equipment. Let's let's go through this because obviously there is a lot of things that need to be prepared before an anaesthetic.
So what I would suggest before undergoing, for example, whatever procedure requires a general anaesthetic is to gather and check. Any equipment that may be required during the induction and maintenance phase of the anaesthetic first, and this includes the anaesthetic machine that should be assembled and checked before and throughout the anaesthetic period. The oxygen and scavenging should be connected and working.
The anaesthetic gases should be topped up where whether you're using isofluorine or sevofluorine. The induction box or chamber should be, assembled. Face masks of different sizes may be gathered.
Towel introduce the autoscope or laryngoscope, so all the equipment that may be required for the intubation of that patient, as well as 80 tubes of different. Size and then obviously our breathing system, which in the majority of cases is represented by NASDPs. Why this is important because obviously these allow us to to run things much smoother during the anaesthetic itself.
Now, let's go through the next phase. What do we require during the anaesthetic itself? Maybe the breathing system or ventilators, for example.
Now, as we said that the SST piece is the one that is more commonly used, because as low resistance and little that space, also the availability of a reservoir bug and a valve allows mechanical ventilation or actually manual ventilation whenever. Whenever possible or necessary. However, other non-rebreeding circuits such as the ones listed here can also be used, and the majority of these allow rapid changes in gas concentration for minor changes in vibrizer settings, which is extremely useful, for example, when we need to either deepen our anaesthetic or reduce the .
Delivery of the gas an aesthetic. The mechanical ventilators, such as the one that you see shown here in the picture, can be used obviously whenever the animal is intubated because they allow obviously to modify the tidal volume, the rate at which the tidal volume is delivered and the breadths per minute, but obviously they cannot be used unless the animal is incubated. All the equipment that is required for the monitoring of the patient during the anaesthetic also needs to be gathered and assembled for use during the anaesthetic and not looked for during the anaesthetic itself, and this may include simply a stethoscope, a ventilator if the animal is going to be intubated, a capnograph, the pulse oximeter, Doppler andometer if we are going to measure the blood pressure of that animal, and an ECG monitor if if available.
Obviously everything that is required to maintain the body temperature of that patient should also be gathered, and this may include water recirculating heat mat, and the bag incubator, and everything that obviously will be required during the recovery phase, such as, as I said, the incubator as well. Now it is important to provide adequate fluid therapy during the anaesthetic period and in the recovery phase, and it is extremely important to warm up these fluids to body temperature and never give cold fluids to a patient that is especially anaesthetized and my. Proceeding drivers are extremely useful to provide a small amount of fluids throughout an anaesthetic procedure, especially, and maybe bottleworms, which is, you know, the ones that are generally used for babies are extremely useful to warm up syringes or full bags of fluid during the anaesthetic.
Now it is difficult to tell you which is the best anaesthetic protocol to use because this largely depends on the clinician's preference. It depends on the clinical conditions of the patient. It depends on the procedure which is going to be performed.
So all these drugs that are listed on this slides are actually, you know, obviously. Can be used. They can be used in combination.
There are lots of protocols that have been published out there or that are anecdotally used. So I won't say which is the best one because there isn't a best anaesthetic protocol or the best anaesthetic protocol is what makes you feel safer, what you know probably the best, and what it is safer for that patient in that specific condition. So obviously, an anaesthetic can be induced to giving drugs intravenously, intramuscularly, or subcutaneously to these patients as well.
However, in the majority of cases, induction of a general anaesthetic, at least in rodent species, occurs by using induction chambers or specialised boxes as in the pictures that you see here, or by using a large face mask if the patient is very small. So differently that from what occurs in rabbits in in which species induction of a general anaesthetic by simple use of a gas anaesthetic is not recommended because it can cause stress, panicking, injuries, a breath holding, and ultimately leading to hypercapnia, hypoxia, and bradycardia in. No rodent species, this is considered the most common way of inducing anaesthesia.
However, I do have to say that I personally prefer to use a combination of a sedative then followed by induction with with a gas anaesthetic to reduce the stress of the animal during the handling and to make the induction of the anaesthetic with, with a, a gas anaesthetic less stressful for the patient. Now you can see from these pictures on the left hand side there is a box that is being purposely purchased for for this reason, so it is an induction chamber that can be, that is commercialised for this purpose. In the mid, the, the mid picture shows simply.
Perplex box that has been made into an induction chamber and on the right hand side you see a large size face mask that is used in a, in a hamster to as an induction chamber itself. So all of these methods simply work. Now intubation, intubation remains the mainstay of a general anaesthetic because it allows maintenance of a patent airway.
It allows reduction of that space, allows delivery of gas, anaesthetic and the oxygen. And also allows intrapositive pressure ventilation wherever this is. However, it is not so easy in rodent species, and I'm talking mainly about the guinea pigs and the chinchilla, which are the largest of rodent species that we generally deal with.
The reason for reaching guinea pigs and chinchillas is not so easy, is an anatomical feature. Their caudal tongue is continuous with the soft palate, leaving us more opening within the mouth, which is called the palatal osteum, which represents the only connection between the oropharynx and the pharynx. Therefore, this complicates greatly intubation in these species, intubation in a blind way like we attempt.
Era it is not possible in this species because it can cause traumatization of the palatal osteoma leading to edoema and in some cases haemorrhage. So the only, the only options in these species are either using an endoscope or a modified otoscope such as a vaginoscope, for example. The endoscope can be used either sliding the ET tube over the endoscope, depending obviously on the size of the endoscope, the size of the ET tube, and ultimately on the size of the patient, or using the side by side technique, so sliding the endoscope to the side of of the ET tube by guiding its placement into, the, and through the glottis.
However, this requires some practise. Now, the other option is obviously, and this is especially in case of an emergency, a tracheotomy or a tracheostomy. These are definitely possible as you can see on the right hand side, this is a tracheostomy that has been performed as an emergency in a guinea pig undergoing facial surgery.
So this is definitely a possibility and the technique is exactly the same as the one used in dogs and cats. Now rats and rodents definitely can be intubated or whether they do require specialised equipment. There are work standard intubation packs that mainly are used in laboratory settings.
So there are semi-flexible video and the scope of about 1 millimetre size of which are definitely useful for intubation of these species. However, in the majority of cases in our clinical, you know, everyday job, these, . This is not possible, so that and the very small rodents are generally not intubated but are maintained simply using a face mask.
You can see a chinchilla on the right side being maintained under general anaesthesia with use of a tight fitting mask. And remember, obviously in all these cases a pollution of the environment and exposure of personally is always a concern. On the left hand side you see a More connector, more plastic connector, and I believe these are now including in every new TP that is ordered, can be used for maintenance of very small species.
Obvious it's very important here to always check that the muscle of the patient is exactly positioned within the connector so that obviously gas anaesthetic is not, is not polluted into the the atmosphere. Now monitoring obviously is extremely important, and there are a series of parameters that can be and should be monitored throughout the anaesthetic procedure because this allows to pick up abnormalities at a very early stage so that this leads to a very early intervention and obviously increases the chances of a positive outcome. So let's go through each, each of these monitoring parameters.
Now, the best way to monitor an anaesthetic is obviously a nurse. A nurse is what makes the anaesthetic safe. A very good nurse can detect abnormalities very early is what obviously tells the clinician that there is a problem going on so that the clinician can obviously act and ask the nurse to.
I immediately, so there are a few things that we can do very, very easily to monitor efficacy with efficacy of this patient during an anaesthetic starting from reflexes. There are certain reflexes which are extremely useful and despite the fact that their reliability may vary across species, they're actually extremely useful to evaluate the depth of a general anaesthetic and the responsiveness of the patient to painful stimuli. The right ear reflex is probably the first one that is lost during a general anaesthetic and can be obviously assessed very, very easily.
Pedal reflex, ear pinch, jaw to, toe pinch, and tail pinch are the ones that are most commonly used to assess whether a patient is light and whether a patient is actually responding to a painful stimulus and is therefore ready or not to a surgical procedure. It is important to remember that there are minor variabilities depending on the species. For example, pedal reflex varies between the front and back legs in mice, and there are other reflexes such as the pappiro reflex, for example, that may be maintained a surgical plane of anaesthesia depending on the drug that is used to anaesthetize the, the patient, so may not necessarily be an indication of a light plane of anaesthesia.
So this is always important to consider. Throughout the the anaesthetic and the surgical procedure, it's important to check the positioning of the patient so that the chest is always maintained slightly elevated compared to the abdomen. We've already discussed the importance of this to avoid the compromising.
The respiration of that patient, it is always important to avoid the corneal ulceration. The gas anaesthetic tend to obviously dry, the, the eye, and it's important to lubricate throughout the anaesthetic procedure, both sides and to continue doing that in the post-anesthetic period. And vital parameters to check throughout the anaesthetic procedure include respiratory rate, and this is very easy to do, especially when we are using clear plastic drapes that facilitate monitoring of the patient.
Heart rate, which can be monitored with a Doppler, for example, with a normal stethoscope or with an esophageal stethoscope. Body temperature can be assessed with a normal, thermometer. There are some multiparametters, equipment which also include temperature probes.
The blood pressure can be measured obviously in the larger wooden species such as, for example, in guinea pigs, although it may obviously be more important in terms of trends rather than in. Absolute values as it is for all these vital parameters. The entidal carbon dioxide, so the amount of carbon dioxide expired at each breath, can be measured by using a car graph, and obviously this is important in intubated animal.
And the the oxygen saturation of haemoglobin can be detected with a pulse oximeter as you can see in the right picture of being used in in a rat. Now, as we said, a stethoscope is probably the easiest way to monitor the cardiovascular function. And the stethoscope allow us to determine the heart rate, concurrently with the evaluation of the quality of the femoral poles, and an esophageal stethoscope can also be used in larger species.
You can see, on the, in the top right picture being used here in a guinea pig, however. I do find it extremely useful to use a Doppler which amplifies obviously the arterial flow and which can be applied either directly over the heart or on the ventromedial aspect of the carpus, for example, or along the ventral pans on the carpus or the tarsus, where obviously it's possible to detect arterial flow. Blood pressure may not be so easy in certain species, but for example, you can see with a very small cups, which allow us obviously to determine these parameters in a smaller species as well.
There are some ECG monitors that can be used in small mammals as well, and now there are alligator forceps available specifically for small mammals which are less traumatic, so they may be used for, you know, for, for this, for this patient. The post oximeter may not be so reliable in many cases, it doesn't cover like directly with the the arterial oxygen concentration and also it's very difficult to use in pigmented animals. Therefore, it's not the most reliable way to assess oxygenation of of the patient.
What about respiratory monitors and the carnography? Respiratory monitors that are being used for dogs and cats are often. Not cannot be used in very small patients because of that very high heart rate and respiratory rate.
Cypnography, there have been some studies regarding the use of cypnography in the conscious, in conscious and non-intubated rabbits, for example, which have shown that cypnography is not so reliable in these patients. So the use of a carnograph in the anaesthetized non-intubated rodents unfortunately is. Probably something that is not so reliable, but at at this data, there are not many studies that suggested this as being true.
So the most useful way to monitor the ventilation of the patient is to monitor the respiratory rate. Unfortunately, the carnography, which is so useful in evaluating the ventilation, the oxygenation of the patient when this is intubated may not be so useful when the animal is not is not intubated. Now, as we said, the temperature monitoring is extremely important because hypothermia prolongs recovery, can increase the potency of volatile anaesthetic, can depress greatly the cardiovascular function, cause coagulation disturbance, and ultimately highly increase the anaesthetic death.
Now we mentioned at the beginning a study looking into the per anaesthetic mortality rate of different. Species including rabbits and guinea pigs. One of the common reasons for per anaesthetic stability rate was hypothermia alongside respiratory depression.
So it is always important to check the temperature throughout. It's also important to consider that these patients have a high body surface to volume ratio. Therefore they lose heat very, very rapidly.
These are associated with the fact that thermal regulation is depressed. During the anaesthetic and we are also increasing the the heat loss during the anaesthetic because we are using cold and dry gases, we are shaving the animal, we're using alcohol, for example, then obviously these increases further risks of hypothermia. How can we control this?
There are loads of ways to provide thermal support and there is a long list here of possibilities we can use warm water. Gloves we can use heat pads, recirculating warm water blankets, bear huggers, whatever is the device that we use, it's always important to prevent burning by preventing direct contact from with the device and the patient body surface. It's always important if we are providing intravenous fluid to warm the fluids as well, as we, as we said.
And it's also important to remember that the majority of the heat in these patients is lost by radiation. That means that the most effective way that we have to prevent heat loss is to reduce the gradient difference between the animal's body. Temperature by wrapping the animal and insulating the animal.
For example, we can use cotton wool, aluminium foil, bubble wrapper to wrap the tails or the extremity to prevent loss and the environmental temperature by warming up the the surgery, for example, if we are in theatre. Now, as we said, it is always important to monitor the patient and to continue monitoring the patient throughout the peri-anesthetic period. The majority of mortality rates related to an anaesthetic actually occurred the 3 hours of post anaesthetic.
So it is always important to continue our observations at regular intervals once the anaesthetic is, is come to an end. If possible, it's always important to reverse the anaesthetic and continue checking, all the vital parameters that we've been checking throughout the anaesthetic itself, for so the temperature, body position, stimulation, obviously, if possible, should be, provided at regular intervals at least at the beginning and obviously. Reduced infrequency as soon as the animal starts to come round because obviously these provide further stress and continue with the breathing support and fluid therapy, especially when the animal is is recovering or taking longer to, to recover from, from an anaesthetic.
So initially the recovery should occur in an incubator, for example, if we need to provide the supplemental heat or in a warm enclosure, which may be, for example, the cage where the animal is returned with some warm equipment, you know, within it. It's always important to hospitalise these patients away from dogs and cats or predators in general. And what's the aim?
What we need to achieve during the recovery? Can, can we actually leave these patients alone? We can't because it's important to continue monitoring regularly these patients until they are able to regulate and control the temperature until the patient is showing increasingly more voluntary movement.
Until those biological parameters that we've been checking from the beginning of the anaesthetic throughout the anaesthetic itself are actually returning to the baseline levels and we understand now the importance of collecting those baseline parameters not from a book but directly from our patient because these are the parameters that we've been checking throughout the anaesthetic and We will continue to be checking in the recovery phase as well, and it is important to encourage these animals to eat as soon as possible, as soon as they're able to swallow and move around because of their high metabolic rate and because of the high consumption rate, the high oxygen consumption rate and low glycogen reserves. So caloric support is extremely important for all the small mammals because of the high metabolic rate. The easiest way to do that is to provide a syringe feeding.
There are loads of recovery formulas out there now that can be offered to these patients depending obviously on their feeding habits. Nasogastric tubes are being reported for use. In guinea pigs, but they are not so common.
These animals are very easily stressed, so it is important to provide the food in the most natural way possible and reducing handling and stress as much as possible as well, because stress can have a negative impact during the period anaesthetic period. So it's always important to reduce that to a minimum. Pain is also extremely important, as we said, they are pre-species.
They tend to mask signs of disease and they're often presented or anaesthetized when actually their anaesthetic risk is much higher than what we would expect simply because they didn't look as sick as they were actually. Now in a study that was performed not long ago, it was looked at the the percentage of animals that were treated for pain when undergoing the same procedure. Now this study showed that 50 to 70% Dogs and cats were prescribed analgesic, whereas 21% of rabbits and rodents for the same procedure received painkillers.
This is obviously not acceptable because they are small mammals and they have the same pathway that we do and dogs and cats do. The problem is simply in the fact that we are unable to recognise when they feel pain, simply because they tend to mask signs of pain. So it is important to be very observant, to observe their behaviour and just knowing what they, what it is normally their behaviour will be able to understand what it is abnormal and potentially sign of pain and to observe the food and water intake because this will be in the majority of cases, the first sign that there is an underlying problem.
So it is always important, especially if the general anaesthetic is aimed at a surgical procedure to to treat the pain in advance. We've already discussed about balanced anaesthesia in the anaesthetic cocher, an analgesic may always be, may be included as well, and the preemptive analgesia so that the pain is. Treated before the painful stimulus is applied for more effective pain management.
Now opioids and non-steroidal anti-inflammatories often in communication are the drugs more commonly used. I just would like to stress the fact that these the majority of these species have a higher metabolic rate. Many of these drugs are.
Much faster, so the dosage should not be directly extrapolized from dogs and cats. Always check the literature wherever it is available because many of these species will actually require a much higher dose for many of these painkillers as compared to dogs and cats. In some cases, even 5 to 10 times higher as compared to other species.
Now, as we said, it is important before any anaesthetic to be extremely prepared in terms of equipment but also in terms of emergency equipment. It is important to act as soon as possible, so we should not waste the time in looking for things that should have been already there in case of an emergency. So it is important to respond, for example, when a heart rate is actually starting to slow down, when it's showing to be irregular, when the patient is becoming oblique.
These are the three most common things that we, we should react to and promptly. During an anaesthetic of a of a small mammal, reversal drugs should be used if if available, and emergency drugs should be pre-calculated and written on, on an anaesthetic sheet so that when the actual emergency occurs we can immediately draw up or administer directly the emergency drugs, as we said, and as you can see from this chart. Many charts actually that already show the precalculated dose for the weight of the animal.
It is important and it is actually very easy, very easy to have these charts in your crash box because you can immediately identify the dose that is required and you can see in many of the cases you have 0.04 or in some cases you actually require further dilution for a smaller patients. It's always important, as you can see in this picture here, to have intubation equipment cloth if the animal is not already intubated, as well as a number bag or a mechanical ventilator if available in case of respiratory depression or respiratory arrest.
Now, in general, The principle of basic life support, so the CPR is actually no different as compared to dogs and cats, and they are exactly the same principle. They are applied to rabbits and rodent patients as well. The major difference is the fact that in the majority of these patients we are actually.
The time that we would have, for example, with dogs and cats, so it is important to recognise if there is a problem at the early stages that we can actually promptly intervene and reverse the problem sooner rather than later because in the majority of cases what we lack is actually a time. So when actually an anaesthetic end, when can we say that the animal is safely being, you know, anaesthetized and can go back home, for example. As a general rule, we say that the patient as as, you know, I finished, it is passed.
The anaesthetic when he's shown sustained voluntary movement, when he's demonstrated the ability to regulate his body temperature by itself, and when those baseline biological parameters that we've been checking throughout the procedure have actually returned to baseline levels. As we mentioned before, the majority of deaths actually occur within 3 hours following an anaesthetic procedure. So I will stress out that an anaesthetic is not actually the time period during which the animal is undergoing the anaesthetic itself, but it is also the time after that because we should not let our guard down and we should continue to monitoring these patients very, very closely.
So which is the take home message tonight? I think the first point to consider is to be prepared and plan the anaesthetic and the procedure appropriately. It is important to gather all the information that is possible on the patient.
It is it is necessary to gather. Make checklists, for example, of all the equipment that is required for that specific anaesthetic and procedure and plan everything accurately so that everything is not left to chance but is organised very immediately. It's also important to remember that we do things.
We can simply use knowledge and established established skills that can simply be adapted to the species specific requirement of small mammals. Now it's important to remember that small mammals are not small dogs and cats, but they have very, very specific anatomic and physiologic features which in many cases are completely different to those to those of. Dogs and cats, so the knowledge that we have from other species and the skills that we use in other species can simply be adapted to their requirements, and this represents an actual skill, a further skill when especially anaesthetizing these patients.
And also whenever possible, it is important to invest in products and equipment that may improve the success, the efficiency, and the safety of small mammal anaesthesia. I hope you, you enjoyed the webinar and if you have any questions, I'm very happy to answer. Right, let's have a look if there's any questions.
I had a question. If there is a prolonged anaesthetic, would you check the blood glucose on arousal? And would you monitor that?
Over a period or not. It really depends on the species, for example, I would definitely do in ferrets, because an anaesthetic can exacerbate underlying, insulinomas, for example. So definitely that is something that I would do at the beginning and throughout if there are any issues.
I do not regularly do in Rodents, for example, and also consider that in many cases you may not have an intravascular axis in these species as well, especially in the very small ones. For what concerns rabbits is not something that I tend to do routinely. Sometimes we do that at the beginning, for example, especially if there is a gastrointestinal issue that is suspected.
But unless there is hypoglycemia at the beginning that we do not tend to monitor that throughout the anaesthetic. It requires sometimes that we do that in the post anaesthetic period, but I would say the only one species whereas this is a concern that maybe be more ferrets unless obviously we know that there is an issue at the beginning. Oh, thank you very much.
No, no questions so far. Well, I hope everything was clear. I think we pretty much covered it in your webinar anyway, to be honest, there's a lot of information in there.
So thank you again for your webinar. Thank you to everyone who attended the live webinar. If you do happen to think of any questions afterwards for any of the attendees watching, if you do email the, email the office, this should be passed on to, Elizabetta.
No problems at all. No problem. It's great to have your company.
Thank you for providing feedback on the webinar and thank you to my co-host, Dawn and Lewis, and I hope you can join us for another webinar. Enjoy the rest of your evening. Thank you.
You're welcome.
