Vision in companion animals - what do our pets really see?

In one study, police dogs could see a stationary object up to 585 metres away, but if it was moving they could see it 900m away. (I took this photo in Colorado on a very hot day. The police were inside having lunch and left their dogs in the car. When I raised my concerns they explained the engine was running and the air con was on. I asked "what if someone tries to steal your car?". Uh. No one is gonna steal that car with that dog in the driver's seat!)

I’m often asked what dogs or cats see compared to us, and the truth is I am usually stumped for an answer. Veterinary ophthalmologist Dr Cameron Whittaker gave a talk last week at the Animal Referral Hospital on vision in companion animals which answered my questions, and he's kindly allowed me to use his slides.

Visual perception is the process by which we organise or make sense of the sensory impressions caused by the light that strikes our eyes. It is affected by our knowledge, expectations, neurological state and motivation. (Dr Whittaker pointed out there is substantial scholarly literature confirming the impact of “beer goggles” on our perception of attractiveness of others. I can see several very entertaining PhDs in that).

Humans and animals visually discriminate objects via sensitivity to light, sensitivity to motion, field of view, visual acuity and colour vision.

• Cats can detect light at seven times lower luminosity than humans, i.e. their night vision is much better than ours. Their secret is the tapetum lucidium, a specialised part of the choroid which reflects light a second time so the retina can capture more of it. It is present in most domestic species except for pigs and guinea pigs.

So do dogs and cats see in colour? It’s hard to test, but the consensus is yes. Cone photoreceptors are responsible for colour vision and are present in domestic animals, with the number and type of cones varying between species.

• We have three types of cones: red, green and blue.
• Dogs have two: blue and red. They probably confuse red and green and see them as grey. They can probably distinguish a red ball from a green one on the basis of the brightness of the two, but they essentially see colour like a red-green colour blind person.
• Cats have three cones but may only detect colour differences if these are pretty obvious.

Slide courtesy Dr Cameron Whittaker.

Brightness discrimination in dogs is 2x worse than in humans. What that means is we can see more shades of grey (this may be why so few dogs appreciate “50 Shades of Grey”)(okay, sorry that was a dad joke).

Slide courtesy Dr Cameron Whittaker.

If you want to know how well your dog or cat can see in comparison to you, the answer – providing you have average vision – is this:

• They likely see better at night
• They see less colour or may not see colours in the same way
• Their vision is probably not as good during the daytime as they have reduced visual acuity
• They are much better at detecting peripheral motion
• They probably have fewer blind spots.

Interview with Dr Caleb Frankel, tech-savvy ER veterinarian

Dr Caleb Frankel with Voodoo (note matching bowties). Voodoo had a not so great start in life - now he's living the dream!

For those who don't yet know it, SAT recently joined the Twitterverse [@fawcettanne - tweet me!]. The social media naysayers may argue that Twitter is another source of whitenoise, spam and time-wasting...but its a brilliant way to connect with like-minded people in your field. Like Dr Caleb Frankel, founder of VMDtechnology.com and, it turns out, a passionate ER veterinarian, family man and rescuer of animals who have done it tough. He tweeted, I re-tweeted, we exchanged URLs and bam! SAT scored a wonderful interview.

Hi Caleb! Can you tell us a bit about yourself?

Hi SAT world! I would call myself a veterinarian by trade and a “techy” by hobby. I also have an unexplainable desire to wear bow ties. My day (and sometimes night) job is as an emergency veterinarian in a 40-doctor [ed: phwoar! 40!!! That's HUGE.] specialty and emergency animal hospital outside of Philadelphia, PA USA.

What attracted you to emergency and critical care? 

Actually, I was strongly attracted to internal medicine coming out of veterinary school. I was set on a residency. I love complicated cases and am a bit of a medicine head, and I pursued a high-quality veterinary internship with that goal. Then a funny thing happened – I realized I was good at and enjoyed emergency medicine more than anything else. I guess it’s the constant challenge that I love the most. I also truly enjoy helping people through tough times and most of my emergency cases involve families in stressful situations.

Dr Frankel with colleagues.

Do you ever see cases which make you question your move into emergency and critical care?

Yes! I think anyone in the trenches of our profession has days where the “grass is always greener.” My job is often very stressful (whose job is not in vet medicine?). Pet owners are often distressed, animals are very sick, and it can take its toll on nurses and us ER doctors. Sometimes I think it would be nice to have scheduled appointments all day or at least see a mix of routine and sick cases. Luckily, I have a network of general practices where I can do relief work if desired. The emergency hours are also not always conducive to having a family and a life outside of veterinary medicine. I’m lucky to work in a practice where work-life balance is valued whenever possible. At this point in my career, I’m very happy where I am. 

How did VMDtechnology.com come about?

In veterinary school, many knew me as the guy carrying around the huge palm pilot (I’m quick to correct them – it was a Dell Axim x51). I tend to have my pulse on all kinds of ways to make my professional life more organized and efficient. I remember searching for veterinary apps and examples of ways vets use technology early on as a budding veterinary student. And I remember not being able to find much. That was back in the time when smartphones and tablets were barely taking off. So the idea really developed in veterinary school because of a personal need. Now, almost a decade since first coming up with the idea, I’m finally getting it out there. The cool thing is that it has been really well-received already.

Dr Frankel in action.

It has been said before...vets don't seem to be frontrunners when it comes to adopting new technologies. Why do you think this is?

We’re certainly no silicon valley. Being “techy” and being a veterinary professional is not a common combination. It’s similar (and sometimes worse) in human medicine. Take digital x-rays – some of the most modern human hospitals still aren’t fully digital, but many 1-doctor general veterinary practices are. It sounds cliché, but if I had a nickel every time a pet owner told me our hospital was cleaner and more advanced than their people hospital, I’d be very wealthy.

I think medical professionals (veterinarians included) are so finely trained to require evidence and/or experience in order to try something now, that it is hard for many doctors to trust or use new technology. With that said, we are a profession in massive transition. When I was in school, I’d speculate that 10% of my classmates used technology to better their professional lives in any significant way. I’m exposed to numerous veterinary externs/interns/residents from all over the world in my work at specialty hospitals and can say that the vast majority of them are carrying (and using!) smartphones, tablets, websites, etc. regularly in their learning process. The change has been dramatic and real. And it’s awesome!

How do you see new technologies changing the face of veterinary practice?

Even 5 years ago, we couldn’t have predicted that mobile devices such as smartphones and tablet computers would prove so useful for medical professionals. New wearable technology such as Google Glass (see our mini-article here) could push the integration of technology to a completely new level. Then there is always the ever advancing technology within medicine (new procedures, equipment, research…). But I think the technology that will dramatically change our profession is in the evolution of what is now called “practice management software.” I have spent more time thinking about this than anything else, and I’ve developed some really big, and I think innovative, ideas on that topic (stay tuned!).

Can you tell us about any of your favourite apps for veterinarians?

Veterinary Apps are another aspect of technology that lags behind the rest of the world. Our human medical counterparts have a much more extensive list of apps to choose from. There are some interesting things going on in the medical app development world – such as Apple and the FDA’s recent discussions about regulating medical apps similar to medical devices. Currently, my most useful apps are actually “general” ones that I use in for professional purposes. My favourites are Evernote and Google Drive (see our recent two-part article here).

I also use iSilo for the Plumb’s Veterinary Handbook (still awaiting a release of the 7^th edition), the Bayer Target Manual, Epocrates, a few others. A company in Canada, Timeless Veterinary Systems, is doing some really innovative things in veterinary app development. I’m currently exploring their very new app, the Timeless Vet Drug Index, which is evidence-based and really intuitive to use. The future is looking up!

What about your favourite vet-related websites?

Glad you asked! http://www.vmdtechnology.com/top-15-veterinary-websites/

Do you think veterinarians use the web and social media effectively for continuing education? Could we do it better?

This is the very topic of a future post. One of my colleagues is involved in a great new project called VetGirl which is a web- and podcast-based continuing education service for veterinarians. It’s really good stuff- check it out!

[Ed: I did and we've posted about one of the seminar's on smallanimaltalk].

I’m also a huge fan of On the Floor @ Dove. This is probably the most comprehensive online hospital continuing education service out there besides some of the major veterinary websites such as VIN and IVIS. VetVine is another innovative website doing some interesting continuing education work with vets.  I also think our industry’s trade publications (see our survival guide on this topic here) are going to big players in online continuing education in the future. In terms of social media – I see this more as a tool to connect us to these resources, rather than CE resources themselves.

How do you unwind offline?

I try to be very conscious of the importance of offline time. One of my favourite articles that I frequently go back to is a piece in the New York Times on “thebusy trap”. It reminds me about the rat race we have created for ourselves in this crazy connected world and the importance of making time to wind down. Everything in moderation, right? I have many wonderful friends from different parts of my life that I try to spend time with at every possible moment. These days, I spend most of my down time with my wonderful and supportive wife and our new twin sons. I can’t get enough time with them. I am also an eager traveller, live music fan, and enjoy playing and watching most team sports.

[Ed: just downloaded and read that article - loved it!]

Can you tell us about any non-humans in your life - how did you meet and what do you do together?

I’m a rescuer! My best buddy Voodoo is an 8-year-old Labrador/Boxer mix who was rescued from a terrible situation when I was in veterinary school. He loves to rough-house and play ball, although these days his favourite pastime is acting as a stationary vacuum below two high chairs from which yummy snacks constantly rain. I also have a cat named Benjamin Franklin who was rescued from a house fire when he was only days old. He is a little prickly, and likes to be pet, but only on his time.

Any parting words of advice for veterinarians and veterinary students?

We’re a really unique group of individuals in a very small profession and I’m always amazed with my colleagues and what you are doing at any given moment. But our profession has some very real challenges. I believe many of them can be solved through technology. So, embrace technology. Tinker, explore, innovate! That and check out VMDtechnology.com : )

Three things I learned: endocrine disease in companion animals

SAT readers will recognise this CT image as that of a cat, Bart, who had an adrenal tumour (circled). Adrenal glands, when they aren't pathologically enlarged, can be very tricky to find on ultrasound unless you know the landmarks.

Here at SAT we have learned two things about learning three things: 

1. Attending a lecture with the aim of learning and recalling three things definitely helps us retain the information (maybe a little study tip there?)
2. Its VERY difficult to limit our learning to three things. So for those of you who are good at counting, please give us a little leeway...

Small animal specialist Dr Christine Griebsch gave a comprehensive talk about the use of trilostane to manage hyperadrenocorticism. Her protocol is a little different to the traditional management regime.

• Recent studies have shown that twice daily administration of trilostane at a lower dose resulted in better control of signs, and that the ideal time to run the ACTH stim test was 2-3 hours post administration rather than 4-6.
• At follow up she looks at the history, physical exam, ACTH stim and electrolytes 1-2 weeks following commencement of treatment, then at 3-4 weeks, 6-8 weeks 12 weeks and every 3-6 months thereafter.

Small animal resident Dr Joanna Whitney gave an excellent talk on the diagnosis and management of diabetic ketoacidosis. 

• The most important thing that I learned was that of all dogs diagnosed with DKA, 70% have concurrent disease (commonly pancreatitis, bacterial UTI or hyperadrenocorticism) and in cats 90% have concurrent disease (commonly hepatic lipidosis, chronic renal insufficiency, pancreatitis, bacterial infection) or it may be a complication of glucocorticoid administration.
• So it seems logical that work up of a DKA patient, aside from the general tests such as CBC/MBA/UA, should include urine culture and sensitivity, cPLI or fPLI, abdominal ultrasound, thoracic radiographs and possibly an ACTH stim test.

Finally, diagnostic imaging specialist Dr Mariano Makara gave a very passionate talk about imaging adrenal glands. As he said when one is learning ultrasound, the adrenals and the pancreas are the holy grail as they can be so difficult to locate. He used some amazing CT images to give an anatomical review of the location of the adrenals, and fortunately there are plenty of landmarks for these.

The adrenals are

• -          Caudally in contact with the renal veins
• -          Ventrally in contact with the phrenicoabdominal veins
• -          Dorstally bordered by the psoas muscle
• The right adrenal is in contact with the caudal vena cava (medially) and the right kidney (laterally) – this is a lot harder to locate as it is more cranial and tends to be protected by the rib cage.
• The left adrenal is in contact with the aorta (medially) and the left kidney (laterally).

Once you find them, as he explained, interpretation is not too difficult…they should have a short axis of 0.6mm in a small breed dog and 0.7mm in a large breed, and enlarged adrenals look puffed up. Adrenal masses generally look quite distinct.

CT is often required to confirm invasion of the caudal vena cava by an adrenal tumour, and this is something that Dr Makara recommends for any dog about to undergo adrenalectomy.

You can read more about Bart's adrenal tumour - and his concurrent brain tumour - both successfully treated - here.

The making, baking and enthusiastic masticating of Sofi's dog-friendly birthday cake

Sofi's dog-friendly birthday cake.

Sofi is a one-year-old Cavalier King Charles Spaniel. She’s a patient, a friend and a well-loved member of her family.

But first, a necessary and serious discussion about cakes and dogs.

Birthday cakes are one of those human inventions we like to share with our nearest and dearest, including our non-human companions. The problem is that cakes often contain substances that are toxic to dogs (chocolate and cocoa products, grapes, sultanas and even the artificial sweetener xylitol) and can be fatal.

Some may argue that feeding cake to dog is a dangerous, ignorant expression of reckless anthropomorphism-cum-anthropocentrism. That may be the case if you allow your hound to tuck into a black forest cake or fruit loaf.

But I say there is a middle ground. It is possible to create a cake for dogs which doesn’t contain toxic ingredients or make them unwell. Emma and Alice did just that for Sofi’s birthday party.

IMPORTANT HEALTH WARNING

This recipe contains ingredients which render it unsuitable for dogs which require a low fat diet, have a history of pancreatitis or dogs who are on an elimination diet. It should be eaten in moderation and served responsibly (one small slice per dog at a time). Any variation from the normal diet may cause gastrointestinal upsets in some dogs.

Another warning: this is an undertaking which may result in kitchen carnage. Not recommended for the domestically disinclined.

Your sink might look like this after baking this
outstanding cake. Don't say we didn't warn you!

The recipe is adapted from two recipes in Nibble Munch Chomp: The Art and Science ofFeeding Your Pet, a beautiful book by Lortsmith Animal Hospital veterinarian Sasha Herbert.

Ingredients used by Emma and Alice

Cake:

500g LEAN minced beef

8 eggs

1 cup oatmeal

½ cup dry biscuit crumbs

Leftover tuna pasta

Icing:

6 mashed potatoes (boiled in chicken stock to make extra tasty)

A tiny dash of cream (maybe one tablespoon; you could also use natural yoghurt)

A sprinkle of parmesan cheese

Topping:

2 liver treats broken into pieces

Peas (also boiled in chicken stock)

Corn kernals

Cabinossi slices
Sausage slices

Dog biscuits

To bake the cake

Preheat oven to 180 degrees celcius.

Blend mince, eggs, oatmeal, leftover tuna pasta and biscuit crumbs until smooth

Blend it like this...

Then in goes the tuna pasta...

And into a cake tin like so. Note bowl licking opportunities...

Grease cake tin with margarine and pour mixture in

Bake for 25-30 minutes

Allow to cool then invert onto serving platter.

While that is baking you can be working on the icing (hey, cake baking isn't for loafers).

Boil the tateys in chicken stock to add flavour.

Icing:

Put potatoes on to boil then mash, adding the tiniest dash of cream (eg 1 tbsp per 6 huge potatoes)

The cake cools while the vegies cook.

Spead over the cake (nb Emma and Alice ultimately ended up massaging the icing on with their hands).

Toppings: place artistically as per the first photo.

Serving:

Do not leave this cake unattended. Whilst it might confuse any human guests who wander through your kitchen, it emits that cabanossi-potato-mince-liver treat smell that effectively begs dogs to come and snaffle it off your bench.

When serving cut into small slivers and feed strategically to avoid any food aggression.

You might want to sing Happy Birthday to the dog of honour first. The smell of the cake has piqued Sofi's interest.

Boo and Sofi chow down on the birthday cake.

Meanwhile Louli washes her slice down with a cup of water. (Louli drinks like this when she's out and about, and doesn't mind a glass of water at home either!)

Dog treats and cakes should be placed in an area separate to human treats and cakes. Sofi’s birthday party was held at a fenced in park (the Enmore TAFE dog park) which meant that dog treats could be dispensed from within the park, whereas the human food could be neatly served over the fence. This meant that the human guests could enjoy Emma’s mind-blowing chocolate cheesecakes and kid snacks without worrying that dogs would tuck into them.

Emily, Alice and Jas are keeping the chocolate cheesecakes and kid snacks safely out of reach of the canine guests. The snacks are also helpfully labeled lest unwitting human guests pick up the wrong treats.

I can honestly say it was one of the best parties I've ever been to. The canine joy was palpable. 

This Airedale was angling for seconds!!!

Thank you to Emma and Alice for sharing your cake-baking tips with us and for your awesome photographic record of the process. 

Three things I learned: Top 10 mistakes to avoid in you dyspnoeic patients

Pericardial effusion in a feline patient.

Loyal SAT readers will know that I am a massive fan of webinars…you can sit in your pyjamas drinking cups of tea and soak up excellent information without struggling to find a car park (of course I do enjoy getting out from time to time, don’t want to be giving the wrong idea).

Dr Justine Lee presented a fantastic webinar on the common mistakes veterinarians tend to make in the management of dyspnoeic patients. The webinar was a promo for Vet Girl On the Run  a US-based tech-savvy CVE provider that produces podcasts and webinars that one can subscribe to.

Dr Lee is a board-certified emergency and critical care specialist, widely published in the scientific literature but an author in her own right. You can read more about her here. 

The webinar covered everything from TFAST (see below) to acute lung injury (ALI), acute respiratory distress syndrome (ARDS), breed predispositions and when to give blood vs oxygen.

I learned a lot, but if I had to pick three nuggets of wisdom this would be them:

• I knew about FAST ultrasound (not dodgy ultrasound but Focused Assessment with Sonography for Trauma)…I just hadn’t heard of TFAST (add Thoracic to the acronym). One uses ultrasound to look for effusion at four sites. It’s likely more sensitive than thoracic radiographs in many cases and possibly less stressful for the patient. For effusions to cause dyspnoea you need about 20mg/kg of effusion fluid, which is easily picked up using TFAST. (It’s also a useful way of differentiating cardiomegaly from pericardial effusion).
• Dr Lee was very adamant that vets over-radiograph dyspnoeic cats and really it doesn’t help that much prior to a chest tap. Her argument was very persuasive…she talked us through various thoracic radiographs in dyspnoeic cats and she was right…rarely did they yield a diagnosis or reveal something totally unexpected. Instead, she is an enthusiastic advocate of TFAST + bilateral thoracocentesis (and gave practical hints to this end). [The one exception is Siamese cats, esp those who smell like cigarette smoke, as they often have asthma or chronic disease which can make the lungs very friable and may lead to a post-tap pneumothorax].
• Interestingly, although we are taught to aim for the 7^th to 9^th intercostal space, (if you go beyond the 9^th you might find yourself aspirating liver), she is not a rib counter. Rather, she palpates to the end of the xiphoid and draws an imaginary line vertical from here…which takes her to around the 8^th intercostal space. A nice shortcut when you have a dyspnoeic patient on your hands. She is guided by the history – if trauma and she suspects air she taps at the dorsal third of the chest, if fluid is suspected she taps ventrally.
• Interestingly she said the most painful part of thoracocentesis is withdrawing the needle from the pleural space, so she tries to redirect it as gently as possible.
• [I’m going to sneak in an extra thing I learned here: Northern breed dogs like huskies are predisposed to pneumothorax secondary to spontaneous bullae].
• It’s easy to make assumptions when assessing the dyspnoeic patient but important to keep an open mind. For example, dyspnoeic small breed dogs with a heart murmur tend to have CHF - but if their HR is less than 150bpm its less ikely to be cardiac (e.g. congestive heart failure) in origin and more likely to be primary respiratory.
• It can be hard to definitively diagnose ALI/ARDS but it is seen in animals with prolonged hypotension, aspiration of stomach contents, sepsis, trauma, pancreatitis, neurogenic pulmonary oedema, cirrhosis, toxic inhalation, animals which have undergone lung resection or multiple transfusions. There are no pathognomic findings but it tends to be acute on onset, not referable to CHF or left atrial hypertension, associated with severe hypoxaemia and visible as bilateral alveolar infiltrates on radiographs.

So that is more than three. 

I love listening to a speaker who has years of practical experience behind her. The talk was peppered with clinical examples (some hair-raising, but all helpful) and Justine and her associate Dr Garret Pachtinger were happy to answer a lot of questions on the topic.

(And one more thing I learned. Dr Lee is a keen toxicologist and discussed a number of her cases, and mentioned that albuterol inhalers are fine when used appropriately but when your dog chews on your cat’s puffer, the resulting albuterol overdose can lead to massive tachycardia, bronchodilation and hypokalaemia which can be life threatening).

If you missed the webinar there is another being held on Monday August 26 7-9pm, which in US EDT is the same as 9-11am in Australian EST.  The new topic is "Top 10 mistakes to avoid in your emergency patients" and you can register here. This is a complimentary webinar so if you'd like to try out this style of learning its worth setting the time aside.

UPDATE: If you want a more in depth review of respiratory physiology you might also want to enrol in the CVE's TimeOnline respiratory physiology course which starts today. The notes look excellent and there is good video and text support material. www.cve.edu.au

Sofi's birthday party

Sofi (rear) with the love of her life, Boo, at Sofi's first birthday party.

Phil and I are back from the most excellent dog's birthday party ever, and recovering under our respective nanna rugs. It is the weekend after all. 

But we wanted to give three cheers to the hosts, Emma and Alice. I was sent an article only this week about parties we should be having instead of wedding parties, and after this morning I feel that dog birthday parties should be number one on the list.

[Of course there is always a caveat: there are plenty of contraindications for dog birthday parties - dogs that get stressed around dogs and/or people, dogs with a tendency to be aggressive and those with severe dietary restrictions may not appreciate such an event...so you have to exercise careful, dogcentric judgement].

Its doubtful that Sofi knew it was her first (I'd love to know more about how dogs percieve time) but she loved the fact that her favourite dogs, humans and a truckload of cabinossi were gathered in one place.

Emma and Alice, with the assistance of the wonderful Aunty Kat, skillfully ensured that dog treats and human treats were restricted to the appropriate species.

And the cake? Well, we've got exclusive access to the recipe, the making of (and devouring of) images, so we'll be bringing that to you shortly.

Happy birthday Sofi!