The Laryngeal Paralysis Trifecta (larynx, esophagus, rearlimbs): Perioperative Management of the Geriatric Onset Laryngeal Paralysis Polyneuropathy Patient (GOLPP)
The weather-driven veterinary diseases and injuries are not as striking winter to summer here in California as it is in The Great White North, but I suspect Lar Par rears its head more as we approach spring even here…hence the micro-CE topic this month. When does spring arrive here, anyway? (The farmer in me needs to readjust!)
Geriatric Onset Laryngeal Paralysis Polyneuropathy (GOLPP) has three common components,
- laryngeal paralysis,
- a flabby esophagus (my term; just short of true megaesophagus), and
- rearlimb weakness (most often misdiagnosed as generic “arthritis”.)
It is also most commonly seen in geriatric dogs with a myriad of other chronic, unrelated problems to consider and accommodate.
The most common trigger for respiratory crisis for dogs with Laryngeal Paralysis is excitement. Travel to the vet is a big, big trigger! Knowing this, we can plan ahead with the family and prepare for arrival at the clinic. Having a back-up plan when a respiratory crisis does occur makes for a smoother patient management experience for everyone!
The most common time for the major surgical complication—aspiration pneumonitis/pneumonia—to happen is in-and-around the anesthetic episode. For this reason, careful and systematic preparations for this period are beneficial to a successful outcome.
This uptick in risk in-and-around anesthesia is related to several factors—a) anesthetic drugs inhibiting lower esophageal sphincter tone, b) poorly controlled airway and swallowing, c) increased abdominal pressure during patient handling, carrying, manipulation under anesthesia. These are all circumstances we can modulate with specific planning before, during and after a tieback surgery.
Most of these Laryngeal Paralysis patients are geriatric and commonly experience some degree of anxiety when separated from their owners and while in uncommon surroundings. This factor adds to the preoperative risk of respiratory crisis and increases the postoperative concern for regurgitation and surgical failure (from barking!) A few modifications to how we schedule our procedure and manage our clients during the visit can dramatically ease these anxiety-related concerns. These geriatric dogs often have other (unrelated) chronic maladies that we can acknowledge and support such that we don’t make them worse with our surgical efforts toward improving their airways.
Planning Protocol for Laryngeal Paralysis Cases
Pre-Visit
- Prescribe pre-operative promotility medications for 3-5 days pre-op (Cisapride, Ranitidine, low dose Erythromycin or Metaclopromide, in order of preference) **Compounding pharmacy may be required; plan ahead.
(Why? Poor esophageal function associated with GOLPP predisposes to silent regurgitation and increased risk of aspiration; maintaining a stomach empty of fluid is ideal during the anesthetic episode.) - Schedule surgery day to include only a brief pre-op hospital experience and early discharge appointment (total hospital time approximately 2 hours).
(Why? Anxiety and stress are common in geriatric patients and both snowball into other patient management problems. ) - Consider doing preanesthetic and disease work up prior to day of surgery.
(Why? Geriatric patients often have abnormalities that need decisions and/or treatment, and at the very least, a client discussion. ) - Strongly consider Trazadone or Gabapentin (higher end dosing) for pre-op travel, testing dose before day of surgery).
(Why? Travel is a big trigger for a breathing crisis; soothing the travel anxiety might prevent or reduce the severity of this challenge. ) - Advise and/or Rx systemic antacids x 7d preop (only if compounded Ranitidine is not being used for motility; famotidine, omeprazole – no preference)
(Why? The time in & around anesthesia is when silent/overt regurgitation usually happens; even with all of the special preparations this may occur. If we can keep the gastric pH higher than typical, the regurgitated and potentially aspirated gastric contents will not be as caustic to the lungs.) - Avoid acepromazine and steroids when possible.
(Why? Patients tranquilized with acepromazine seem to be at increased risk of silent regurgitation. Steroids decrease gastric pH, increase panting and anxiety, and challenge the immune system; all are counterproductive in perioperative patients. inhaled steroids may be beneficial to reduce/control laryngeal edema associated with more advanced paralysis. )
Day of Surgery
- Low-stress patient handling is absolutely required, utilizing the owner as much a feasible. Avoid traditional head and neck restraint.
(Why? Dogs who cannot breathe well will fight head/neck restraint, making their breathing efforts more labored. Anxiety of separation will make restraint more necessary and make breathing efforts more labored. The goal is to sneak these patients into anesthesia without them noticing! ) - Admit appointment scheduled no more then 30-45 mins prior to surgery start time.
(Why? A long wait prior to surgery will compound the patient’s stress and anxiety and increase the risk of breathing crisis. ) - Place catheter early (right at admit) for emergency access.
(Why? Inducing anesthesia in an urgent manner may be necessary and unpredictable. ) - Administer Metaclopromide, Famotidine, and Maropitant by injection.
(Why? The metaclopromide will keep fluids moving out of the stomach to prevent silent regurgitation. Famotadine will reduce the acid load of stomach contents such that IF regurgitated and aspirated, the resultant pneumonitis/pneumonia will not be as severe. The Maropitant will offset any pharmacological nausea that may result from anesthesia. ) - Prepare the following anesthesia drugs:
- Propofol 4mg/kg
(Why? Rapid induction with minimal inhibition of motor function to the laryngeal muscles; reasonably safe for geriatric population. ) - Buprenorphine01mg/kg, or Hydromorphone 0.05mg/kg, or Morphine 0.5mg/kg, or Butorphanol 0.4mg/kg
(Why? Low to middle dose analgesic to be used after induction to eliminate vomiting concern and avoid inhibition of motor function to the laryngeal muscles.) - Midazolam05mg/kg
(Why? To be used after induction for stress-reducing during recovery and anesthetic-sparing during maintenance. )
- Propofol 4mg/kg
- If the patient is stable, wait for surgeon to participate in induction.
(Why? Ideally, a light anesthesia under IV propofol provides the best exam parameters for diagnosing laryngeal paralysis. ) - In case of emergency respiratory distress upon arrival, place catheter and administer Midazolam 0.05mg/kg and Hydromorphone 0.01mg/kg (or Butorphanol 0.1mg/kg) IV slowly; use increments of the same medications as needed. If necessary, secure airway with Propofol induction and maintain until surgery time.
(Why? Light IV sedation might be enough to stop a breathing crisis and still allow accurate laryngeal exam. Patient safety is more important than a preop laryngeal exam; an intubated/anesthetized patient can wait safely for surgical intervention. ) - Oxygen therapy as-tolerated using blow-by only. No head restraint and no mask delivery.
(Why? Most patient dyspnea is being physiologically driven by elevated CO2 (not low oxygen), so a “fight” to provide oxygen by mask is not helpful. For those being physiologically driven by low oxygen levels, the distress is great enough to recommend moving to induction/intubation directly. ) - When moving the anesthetized patient, support the body by the skeletal structures only, i.e. do not sling them by the abdomen.
(Why? Regurgitation with resultant aspiration pneumonia is the most dangerous complication for these patients. Applying pressure to their abdomen will increase the chances of regurgitation of stomach contents up into the esophagus and then to the larynx and/or trachea. ) - When moving the anesthetized patient, maintain the head at a level higher than the abdomen, i.e. carry at an incline.
(Why? Another regurgitation prevention technique, this prevents gravity from acting on stomach fluids and moving them up the esophagus to fall into the trachea. ) - When moving and positioning the patient before/during/after anesthesia, avoid hard surfaces, rough handling and awkward body positions.
(Why? Remember that these are geriatric patients with less body padding and weaker backs, who are easier to bruise, and less resilient to any physical insult we put to them. )
Discharging Patient
- Plan for owner pick up typically within 1-2 hours of surgery.
(Why? Patient anxiety is to be avoided to prevent stress on repair and the need for further sedation (which predisposes to regurgitation/aspiration. When they have their feet under them, they are better managed in a stress-free, home environment. ) - Go home meds:
- Gabapentin or Tramadol (lower end dosing)
(Why? Useful for light sedation postop and maybe some pain relieving qualities. ) - NSAIDs (half maintenance dose x 7days or continue chronic Rx)
(Why? Gastritis is to be avoided at all costs with the goal of preventing regurgitation or vomiting; NSAIDs may cause gastritis. Surgery is relatively low insult, so may not need higher doses. Dogs with chronic use of NSAIDs and no vomiting/regurgitation are a known low risk with NSAIDs use. ) - Promotility medication x 2 months trial, then refills for lifelong use of successful medication (Cisapride, Ranitidine, low dose Erythromycin or Metaclopromide – in order of preference). (Why? Gastric motility drugs will keep the stomach relatively more empty of gastric fluids. We don’t have any good drugs to help a flabby esophagus or weak lower esophageal sphincter. Trialing these drugs, one at a time, to find the one that works the best to prevent silent regurgitation is advised. )
- Systemic antacids x 7d postop (only if compounded Ranitidine is not being used for motility; famotidine, omeprazole – no preference)
(Why? The time in & around anesthesia is when silent/overt regurgitation usually happens; even with all of the special preparations this may occur. If we can keep the gastric pH higher than typical, the regurgitated and potentially aspirated gastric contents will not be as caustic to the airways and lungs. Not to be routinely used longterm; there is some evidence in humans to support that a lower pH tightens the lower esophageal sphincter, which is beneficial.)
- Gabapentin or Tramadol (lower end dosing)
- Lifelong use of one of the promotility medications is recommended.
(Why? The polyneuropathy creating this condition will continue to weaken the esophagus; ongoing use of motility drugs will help prevent the heartburn and increased aspiration risk these dogs face postop. Clients must be alert to monitoring the drug effectiveness lifelong and report when it is not working well, so a switch can be made. )
The above summary of Laryngeal Paralysis outlines the Trifecta, but I wanted to drill down on one component of the polyneuropathy that underpins the condition. I think of the condition as a “trifecta”– three regions are affected and show us clinical signs, 1) larynx, 2) rearlimbs, and 3) esophagus. The larynx manifests as Laryngeal Paralysis with its associated stridor and respiratory distress. The rearlimbs manifest as weakness, difficulty rising, and a “two-engine” gait with the front legs moving faster than the rear. The esophagus manifests as a “flabby esophagus” (very rarely classic megaesophagus) with silent or overt regurgitation and the enhanced potential for aspirating gastric contents.
The flabby esophagus is probably the biggest contributor to a life-threatening aspect of this polyneuropathy, pre-op and especially post-op– aspiration pneumonitis that progresses to aspiration pneumonia.
It also can be a significant contributor to a reduced quality of life for these geriatric dogs. When the esophagus doesn’t have proper muscle action (because the nerves are bad), it cannot cause normal direction propulsions of food and fluid AND it doesn’t act as a barrier to food/fluid sneaking back up with normal chest movements (breathing, coughing), abdominal movements (straining to defecate, etc.) or head-down positions.
Sometimes owners “see” these food/fluids come up (i.e. they land on the floor). Sometimes they are “silent”, and owners might catch their dogs smacking their lips, burping or swallowing rapidly. And sometimes it is brewing silently as “heartburn, with signs of aggressively seeking to eat grass, sitting up and panting after lying down, restlessness.
Veterinary medicine does not have any medications that will stimulate the esophagus to move in the correct direction. We do have medications that will stimulate the stomach to empty.
40 of 40 cases of Laryngeal Paralysis evaluated (in a Michigan State study) had abnormal esophageal function on the esophagrams they performed (solid food moved better than soft food better than liquid food; I do not recommend soft food for these kids.) From this, my experience and the high incidence of aspiration pneumonia, we should conclude that we should treat this concern specifically.
If we can keep the stomach empty and moving routinely and fast, we can reduce the likelihood of any food/fluid from the stomach sneaking back up the flabby esophagus. The only medications we currently have in vetmed to stimulate the stomach to move (and these data are challenging to interpret thru the years) are: ranitidine, erythromycin (a lower dose than that used as a common antibiotic), cisapride and metoclopromide.
Famotidine, cimetidine, omeprazole and other prescription acid reducers have not been demonstrated to change stomach movement/emptying (again, lots of contradictory data). They reduce stomach acid levels.
Ranitidine is also an acid reducer and what it is best known for, but it also stimulates the stomach movement/emptying. (Ranitidine w/drawn from human market due to the finding of N‐nitrosodimethylamine (NDMA), a probable human carcinogen, in ranitidine products. Levels are tiny and no epidemiologic data is clear on how pertinent the finding is. Since 2018 when it was found “by accident”, and this compound was “looked for”, it was found in multiple other medications; the significance/cause remains undetermined.)
The logic for using acid reducers in these cases is that they will make the reflux fluid less acidic and less damaging to the lungs “when” it is aspirated. These medications do not have data supporting (that I know of) stomach movement effect.
So, strictly speaking about medications to prevent reflux/regurg/heartburn/GERD associated with Lar Par (and there are many other things to do besides medications)– ranitidine, cisapride, erythromycin, and metoclopromide are the drugs we have to choose from. They each have their risks and benefits; I list them in the order I recommend them (based on effectiveness, ease of administration, availability, and long-term risk), and I do trials. If one is not working, move to the next.
The question of whether to use long-term an acid reducer is a tougher one, I think. There is some data to suggest that a lower acid content in the stomach fluids can reduce the “tightness” of the lower esophageal sphincter at the junction between the stomach and the esophagus– MAYBE predisposing to reflux. But, as mentioned above, if fluid is aspirated, I’d prefer the lungs not experience a scalding pH of 2– the pneumonitis and then pneumonia that results is less severe.
This information is how I make decisions regarding my patients with Lar Par. I do not dispute anyone’s personal experience with the use of various medications. But I take the prophylactic treatment of esophageal reflux/regurgitation very seriously, during the surgical/anesthetic timeframe and long term. This complication is THE thing we must fight against very specifically. I believe all patients diagnosed with/suspected of having Lar Par (surgically treated or not) should be on “promotility” medications lifelong, to prevent aspiration pneumonia and make them more comfortable without heartburn.
Until we know more…this is my current “best” practice. This micro-CE is getting lengthy, so I’ll do more on when to know when (for surgical intervention) and the rearlimb component of the Trifecta at a later date. Good luck navigating these tough cases…and give me a call when you want to bring me my favorite surgical experience!
Lara Marie Rasmussen, DVM, MS
Diplomate, American College of Veterinary Surgeons
Direct Veterinary Surgery, PC
directvetsurg@gmail.com
651 829-1111
