Pinnipeds Flashcards
(99 cards)
Young harbor seal unique cardiac finding?
Patent foramen ovale and ductus arteriosus up to 67 week old (ZP)
What is the family and scientific name of the walrus?
What are some defining characterisitics?
- Odobenidae (Walrus (Odobenus rosmarus)
- Flippers – allow weight on them but not very agile
- On land – able to walk on 4 legs
- In water use side to side motion of hind quarters
- Maxillary canine – tusks
- Haircoat – sparse
- Rely on adipose within modified skin and SQ tissue for insulation
- Male walrus – diverticulae of the oropharynx
- More prone to GI obstruction due to smaller pyloric outflow tract
- Flippers – allow weight on them but not very agile
What is the family of sea lions and fur seals?
What are some defining characteristics?
How do you tell fur seals apart from sea lions?
- Otoriidae (sealion, fur seals)
- 14 spp
- Thoracic appendages (flippers) dominant.
- On land – use to “walk” on all 4 limbs
- In water propel with front flippers
- Large trachea, carina near thoracic inlet
- External pinnae
- Have hepatic sinus, but not as prominent abdominal plexus (vs phocids)
- Flat central area to cornea
- Pelage
- Sea lions – short, stout, slick hair
- Rely on SQ fat for insulation
- Fur seals – prominent guard hair and secondary hairs that trap air and help with their thermoregulation
- Sea lions – short, stout, slick hair
What is the family of true seals?
What are some defining characteristics of this group?
- Phocidae (true seals/earless)
- 19 spp total
- Most endangered – Mediterranean monk seal (Monachus monachus) and Hawaiian monk seal (Monachus schauinslandi) and Caspian seal
- Flippers do not allow weight on them
- On land – flounder
- In water use side to side motion of hind quarters
- Lack external pinnae
- Unique anatomy external auditory canal – canal is surrounded by vascular plexus – may protect ear canal from pressures at depth during dives
- Otitis externa in seals housed in shallower pools
- Unique anatomy external auditory canal – canal is surrounded by vascular plexus – may protect ear canal from pressures at depth during dives
- Carina near heart base
- Thermal regulation – skin adaptation & SQ adipose
- Vascular adaptation for diving
- Spinal cord surrounded by vascular sinus
- Site for blood collection
- Large hepatic sinus and abdominal venous plexus
- Diaphragm – muscular sphincter – adjusts cardiac preload during dives
- Spinal cord surrounded by vascular sinus
- 19 spp total
Compare and contrast the internal organ anatomy of phocids & otarrids.
What are the differences in the respiratory system?
What about the kidney structure?
What about skin structure?
What about their teeth?

Describe some of the unique anatomy of pinnipeds:
What about renal anatomy?
Why are their teeth brown?
What adaptations exist for diving?
What is their placentation?
- Appendages (flipper) allow for locomotion in water and thermoregulation
- Femur, patella, tibia and fibula – incorporated within trunk. Tarsus, metatarsus, phalanges – hind flippers
- Reniculate kidneys have a thick capsule and prominent outer cortical veins
- Sexual dimorphism: males larger, large sagittal crest or tusks (species dependent)
- Blubber, no arrector pili muscles in epidermis, increased number of sebaceous glands
-
Teeth: brown discoloration with age
- polyphydont and heterodont
- Deciduous teeth absorbed prior to or at birth, permanent erupt shortly after birth
- Walrus tusks: larger ventral directed upper canines
- polyphydont and heterodont
- Adaptation for diving
- Larger liver and kidney
- Liver and lung lobulated
- Kidney multireticulated
- Vascular adaptations
- Enlarged hepatic sinus, caudal vena cava, proximal aorta and spleen
- Thermoregulation
- AV anastomosis in skin and repro organs
- Lung prominent fibrous interlobular septate
- Small airways reinforced
- With cartilage (otariids)
- Smooth muscle (phocid)
- Combination of smooth muscle and cartilage (odobenid)
- Larger liver and kidney
- Placenta: zonary, endotheliochorial; placental scars can be seen up to 12 months following pregnancy, Delayed implantation
Describe appropriate exhibit design and husbandry for pinnipeds.
Special Housing Requirements (look at Animal Welfare Act requirement) – F8
- Need access to water
- Adapted to maintaining body temp while in cooler waters
- When out of the water, higher risk for hyperthermia
- Ocular disease common
- Protect exposure to solar radiation
- Need to provide shade – darkened non reflective surfaces, feeding underwater and good water quality
- Water quality – Coliform – shall not exceed 1000 MPD (most probably number) per 100 mL of water
Husbandry (CRC 41)
- Pools and Enclosures
- Should be housed in salt water if possible
- Fresh water associated with higher incidence of ophthalmic disease.
- Animals is fresh water need oral salt supplementation
- Provide shade
- Should be housed in salt water if possible
- Feeding
- Typically a mix of herring, mackerel, capelin, squid, smelt in captivity
- Thiamine and vit E supplementation should be provided
Describe appropriate feeding for pinnipeds.
What vitamins should be supplemented?
Do any species have natural fasting periods?
What issues can arise with neonatal pinnipeds?
How is walrus nutrition different?
Nutrition (F8)
- Carnivorous and largely piscivorous
- Captive populations – fed similarly to cetacean diet – teleost fish based (herring, mackerel, smelt)
- Can have thiamine deficiency
- Most facilities supplement multivitamin with Vit A, E, thiamine
- not needed for free-ranging wild pinnipeds as marine fish have good amount of fat soluble vitamins
- proper handling of food fishes – time-temp profile
- shorter the time product is held and colder temp it is held at, higher expected quality
- Some have natural fasting periods
- Ex elephant seal weanlings – fast 4-6 weeks following departure of dam
- Adult male pinniped go “off feed” during time of rut
- Preweaned orphans require mild protein
- Mainly piscivore – protein source other than fish are not optimal
- Pinniped milk – devoid of CHO
- Can have GI probles in hand reared neonate seals
- In wild switch from nursing to eating solids quickly
Walrus Nutrition (CRC 42)
- Not considered “deep divers”. Avg < 100 ft
- Primary prey are benthic inverts – mollusks, clams, invert
- Mollusk removed from shells by powerful suction. Shells are not ingested.
- Captive diet is generally clams, herring, capelin, but often limited by availability.
Describe pinniped handling and restraint.
Where is the ideal injection site for pinnipeds?
Describe intubation.
What are some common issues with thermoregulation under anesthesia?
Restraint and handling F8
Physical Restraint
- In Rehab, field setting – can use barriers
- In permanent collection – training
- can use manual restraint – using towel or conical net designed to fit over head
Chemical Restraint
- Induction time longer and less predictable with thigh muscle injection vs in the neck/shoulder
- Airway
- Distensible pharyngeal soft tissue – can obstruct
- Optimal position – head and neck extension with mouth open. Facilitates intubation
- ETCO2 – usually 70-80 mm Hg
- Core temp – tend to trend towards ambient temperature
- Smaller animals of those that are thin - hypothermic
- Careful with hot water bottles – can cause thermal burns
- Larger or obese animals – hyperthermic
- Smaller animals of those that are thin - hypothermic
Restraint (CRC 41)
- Behavioral – training
- Physical – towel and straddle methods. Limited by sized. Otariids have strong forelimbs.
- Mechanical – Boards, restraint boxes, squeeze cages.
- Chemical
- Phocids: Benzodiazepines, butorphanol, propofol, alfaxalone, telezol
- Masking with iso/sevoflurane possible, but animal may breath hold
- Apnea common on induction, prepare to intubate.
- Otariids: Midazolam, torb, medetomidine, ketamine, alfaxalone
- Smaller animals may be induced with mask
- Phocids: Benzodiazepines, butorphanol, propofol, alfaxalone, telezol

Describe the unique anatomic & physiologic adaptations of phocids that make restraint challenging.
How should these species be transported or handled?
What are commonly used vascular access sites?
Describe intubation.
Anatomy and Physiology
- Thick layer of blubber to insulate body, arteriovenous anastomoses in the trunk and flippers.
- Dive adaptations – leopard and Weddell seals have little cartilaginous support of the trachea and flexible rib cage
- Relaxation of pharyngeal and palatine tissues, muscle of rib cage, and pulmonary airways can contribute to airway obstruction 🡪 susceptible to VQ mismatch
- Dive response – bradycardia, peripheral vasoconstriction, shunting of blood to hear and brain. Controlled by central mechanisms, with input from stretch receptors, baroreceptors, and trigeminal receptors.
- Bradycardia and apnea suggested due to dive response. Dive response could be elicited by anesthetic agents, but cardiac arrest can be elicited by hypoxia in any mammal.
Transport:
- Herd using baffle boards and funneling arrangements
- Captive, wild (Weddell and southern elephant seals)
- Crates - able to open at both ends, well ventilated; width and height that does not allow animal to turn around
Physical Restraint:
- Minimally invasive short procedures - physical restraint in those 100kg or less
- Hoop net then manual restraint vs grasping in front of hind flipper in young
- Larger phocids restrained using a head bag then manual restraint with one person over shoulder and one over hindquarters
- Elephant seals had shorter induction and recovery and less variable responses than those given the agents by IM injection.
- Excessive restraint may compromise breathing via occlusion of the airway or constriction of thoracic wall.
Vascular Access
- The extradural intravertebral vein is most frequently used. Located dorsal to spinal cord in epidural sinus.
- In sternal – dorsal midline in lower lumbar region. Spinous processes of L3-4, needle perpendicular between these processes (18g, 3in harbor seal adult)
- Must sterile prep skin, potential for vessel trauma if struggle and bone marrow contamination
- Plantar interdigital veins of hin flippers also have been used – directly over 2nd digit or medial to 4th digit. Must apply firm pressure to prevent hematoma.
Endotracheal intubation
- Strongly recommended to maintain airway and ventilate.
- Spongy peri-pharyngeal tissues and flaccid soft palate may prevent visualization of laryngeal opening. Weddle seal has narrow laryngeal orifice.
- Most easily done by manual palpation of laryngeal opening. Laryngoscopes can be used if <100kg with aid of a spatula to visualize glottis.
- Apnea may be associated with endotracheal tube placement in elephant seals.
- Robert-shaw demand valve with O2 flow of up to 300L/min

What are some important preanesthetic considerations for phocids?
Describe the administration of anesthetics to phocids.
Preanesthetic considerations
- Rapid and safe restraint, restrict access to water, control temperature and animal interactions.
- Weight fluctuations often the result of deposition or utilization of blubber and lean body mass varies much less dramatically. Blubber less metabolically active – do not dose anesthetic agents on total body mass alone.
- Lipophilic drugs move out of the blood stream and into the blubber more rapidly in fatter animals 🡪 shorter duration of anesthesia, but there may be prolonged drug effects in fatter animals due to gradual passage from fat stores. The time to complete recovery (as opposed to duration of effective chemical immobilization) might therefore be expected to be longer in fatter animals
Chemical Restraint:
- Often not recommended to manually restrain prior to delivery due to heightened state of excitement.
- May be able to hand inject with needle attached to extension tubing. Head bagging can increase operator safety.
- Remote injection - dart or pole syringe
- Large and dangerous species (leopard seal) or those that are known to become agitated or flee when approached by humans (crabeater seal). Must take into consideration flight distance and likelihood that animal will be stimulated to enter the water.
- Response to drug administration is less predictable following delivery by remote delivery systems than manual (extradural vein or lumbar musculature).
- Once restrained - anesthesia induced or maintained via IV parenteral drugs or inhalant anesthesia
- Inhalant is preferred due to ability for precise control of depth and control of airway, less risk
Describe the use of the following anesthetics in phocid seals:
Benzodiazepines
Alpha 2 Adrenergic Agonists
Telazol
Opioids
Propofol
Inhalants
Ketamine:
- Minimal cardiopulmonary depression
- Poor muscle relaxation and tremors when used alone
- Used with benzodiazepines or alpha-2-agonists
Benzodiazepines:
- Good muscle relaxation, minimal cardiovascular effects, and reversible
- Often used as premed – delivered remotely to aide physical restraint.
- Midazolam - rapid onset of action - lipid soluble at body pH
- Moderate to heavy sedation depending on dose
- Harp seals given IM midaz premed did not improve quality of isoflurane anesthesia and had prolonged recoveries in some individuals.
Alpha-2-Adrenergic Agonists:
- Associated with undesirable cardiovascular side effects 🡪 decreased CO, bradycardia, increased peripheral vascular resistance.
- Prolonged anesthetic recovery, bradycardia and variable anesthesia in harbor and elephant seals following medetomidine use.
- Xylazine alone or medetomidine ketamine 🡪 hyperthermia, bradycardia, mortality in leopard and elephant seals.
- Reversible. Has been used in harbor and gray seals alone and in combination with ketamine.
Tiletamine/Zolazepam:
- IM or IV at 1:1 combination.
- Variable planes of anesthesia with prolonged apnea and death in Weddell seals (IM)
- Effective in elephant and leopard seals for induction. Required supplemental ketamine for maintenance. Effective in harbor seals, grey seals.
- IV more predictable with fewer adverse side effects (apnea, muscle tremors) compared with IM
Opioids:
- Reversible, mild cardiovascular and respiratory side effects at low dosages
- Meperidine and midazolam used in elephant seals for deep sedation, but unsatisfactory in leopard seals due to variable responses and respiratory depression.
- Butorphanol in harbor seals provided mild sedation and combined with diazepam allowed for more invasive procedures.
- Potent opioids 🡪 respiratory depression, hyperexcitability, prolonged apnea in hooded and gray seals.
Propofol:
- Short duration, good muscle relaxation, and rapid recovery (IV)
- Large volume
Inhalant anesthetics:
- Useful for prolonged procedures or surgeries
- Large tidal volume 🡪 rapid and efficient uptake and distribution of inhalant anesthetics.
- Prone to respiratory obstruction with reduced cartilaginous support of the trachea. Many phocids have fleshy pharyngeal region that may contribute to respiratory obstruction when muscular tone is reduced by sedation.
Describe the monitoring of phocid seals under anesthesia.
What is the aerobic dive limit?
What are some supportive drugs that may be beneficial for phocid anesthesia?
What are some commonly used analgesics?
Monitoring;
- Plane of anesthesia - head and flipper movements, jaw tone, palpebral reflexes
- HR - - auscultate with esophageal stethoscope, HR by visual of thoracic wall movement, ECG
- Prolonged apnea common – respiratory pattern of sleeping phocids characterized by frequent periods of apnea.
- Aerobic dive limit – defined as time beyond which animal must rely on anaerobic metabolism to prolong the dive. Species capable of deep/prolonged dives (elephant and Weddell) have greater ADL and expected to tolerate longer periods of apnea.
- Hypoventilation - RR and tidal volume must be continuously monitored. IPPV is reduced thoracic excursions or increasing etCO2 noted.
- SpO2 – vulva, lip, tongue. Also use EtCO2 to assess ventilation.
- Respiratory obstruction likely to occur in leopard seals and associated with mortality in this species
- Assisted ventilation if ETCO2 > 55. ETCO2 similar to terrestrial mammals.
- NBIP not applicable due to lack of available peripheral arteries.
- Temperature requires rectal probes > 30 cm in length in large phocids. Can become hyper/hypothermic depending on environment.
Supplemental drugs
- Doxapram – increased depth and frequency of respiration and stimulated breathing in apnea elephant seals (via intratracheal, not by IV extradural sinus).
- May see shaking/hyper-responsiveness at high doses.
- Atropine – eliminated reflex bradycardia in harbor seals but often not routinely included in drug protocols. May also help manage excessive salivation and URT secretion
Recovery
- Deny access to water until fully recovered. Premature removal of endotracheal tube increases risk for respiratory obstruction.
Analgesia
- Butorphanol and flunixin (anorexia reported side effect of flunixin), along with meloxicam and carprofen.
Describe the transport and physical restraint of otarrid seals.
What are the most commonly used sites for vascular access?
Describe endotracheal intubation.
What are some important preanesthetic considerations?
Transport:
- Captive - trained to follow keepers and voluntarily move areas or enter crates
- Herd to different area or into crate with herding boards, chutes, mobile fencing
- Rehabilitated wild or young free-living
Physical Restraint:
- Training for voluntary exams and minimally invasive procedures minimizemk8ctwcs restraint required
- Towels, protective gloves, +/- sedation
- Mechanical or chemical sedation recommended for animals >90kg
- Limitations – minimal duration of procedure, poor accessibility, lack of analgesia, risk of injury and undue stress to the animal
- Control of head is essential
- Front flippers raised slightly and held against side of animal
- Ensure airway integrity – ensure head straight to not collapse trachea, too much weight on thorax inhibits ventilation
Mechanical Restraint:
- Squeeze cages
- Vise or noose that entraps animals neck should be avoided 🡪 collapse trachea due to incomplete tracheal rings
- Monitor MM and RR, ensure do not pinch extremities when squeezing
- Specialized tubular nets – wide enough to capture animal but then taper to point to control the head
- Monitor for hyperthermia and exhaustion after capture
Vascular Access
- Interdigital veins in pelvic limbs – not accessible in CSLs.
- Cephalic, jugular, subclavian, and vessels long digits of hind flipper
Endotracheal Intubation
- Similar intubation to terrestrial carnivores with cuffed ET tubes and standard laryngoscope
Preanesthetic Considerations
- Animals in rehabilitation setting often dehydrated, malnourished, +/- infectious disease 🡪 stabilize prior to immobilization
- Parasitic pneumonia caused by Parafilaroides decorus (CSL) may exacerbate ventilation issues. Hookworm (uncinaria) in fur seals may lead to anemia and make more prone to hypoxemia
- CSL stranding late summer/early fall 🡪 potential for leptospirosis and renal compromise
- Debate over use of atropine 🡪 may prevent bradycardia associated with dive reflex and control airway/oral secretion. Alpha 2 agonists cause bradycardia and some studies indicate use of atropine is associated with increased mortality.
What are the best sites for anesthetic injection in otarrid seals?
What are some commonly used sedation protocols?
Describe the use of the following anesthetics in otarrids:
Telazole
Medetomidine/Ketamine or Medetomidine/Telazol
Medetomidine/Butorphanol/Midazolam
Inhalant anesthetics
Chemical Restraint:
- IV sites – poorly accessible
- IM injections - muscles overlying the lower lumbar spine, tibia and hips, and shoulders
- Hand injection - physical or mechanical restraint
- Remote injection - dart
- Captive and free-living
- Inhalant is preferred due to ability for precise control of depth and control of airway, less risk, titrate to effect
- Training program, physical/mechanical restraint, or use of chemical restraint facilitates inhalation anesthesia.
- Free-living scenario - risk of fleeing to water after darting
Sedation:
- Oral diazepam prior to transport - useful for physical restraint
- Midazolam - more reliable sedation - CA sea lions, fur seals
- Benzodiazepines - reversible (flumazenil)
- Butorphanol - mild sedation and analgesia
- Torb + Midazolam - increased level of sedation
- Medetomidine - sedation for electroencephalography - lack interference with brain waves
Zolazepam/Tiletamine:
- Small volume, low cost, dependable deep sedation and immobilization
- Significant mortality, prolonged recovery, narrow margin of safety reported
- “Top-up” doses to increase anesthetic depth associated with increased mortality. Additional ketamine used successfully.
Medetomidine/Ketamine:
- Effective, safe immobilization
- Moderately variable anesthetic depth, high cost
Medetomidine/Zolazepam/Tiletamine:
- Reliable anesthesia with reasonable cost
- Tremors, ataxia, disorientation during recovery (less than with telazol alone); one mortality
Medetomidine/Butorphanol/Midazolam:
- Reversible (Atipamezole + Flumazenil + Naltrexone), safe, light anesthesia
- Supplemented with isoflurane for deeper anesthesia
- Atropine given after combo injection
- In free-ranging CSL 🡪 superior immobilization than medet+telazol and medet+midaz
Inhalant Anesthetics:
- Isoflurane, Sevoflurane, Halothane
- Iso and sevo - safest anesthesia with best recovery
- Uptake gases very rapidly and efficiently - readily induced with mask
- Inhalants alone - reliable and safe in otariids if possible to accomplish restraint and masking
- Premed and induction with IM meds facilitates masking and maintenance anesthesia
- Once maintained reversible induction agents may be antagonized
Describe the monitoring of otarrid seals under anesthesia.
What SpO2 and EtCO2 values suggest changes are needed?
Monitoring
- Trends in measure variables more important than individual values
- HR, RR, BP, ETCO2, SpO2, temp, CRT
- Plane of anesthesia – response to noise and pain (web or ear pinch), head and flipper movements, jaw tone, palpebral reflexes
- Hypoventilation, apnea - RR and tidal volume must be continuously monitored. Apnea is common and may be due to excessive anesthetic, immobilization drug or dive reflex
- Bradycardia, hypoxemia - auscult with esophageal stethoscope, palpate, HR by visual of thoracic wall movement just caudal to the axilla, ECG
- Sudden or progressive bradycardia - dive reflex (or from alpha 2)
- Blood pressure – cuff on proximal portion of limb or base of tail.
- Pulse oximetry (tongue, nasal septum - large animals, rectally, vaginally, or along buccal or gingival mucosa) – does not reflect adequacy of tissue perfusion
- Low SpO2 (<85%) reported in sea lions with telazol and medet+ket.
- Capnography – elevations or sudden decrease may indicate ventilation problems.
- High EtCO2 (>70) assoc with acidemia support need for mech ventilation in some animals
- Long anesthesia, deep anesth plane and pressure on thorax are prone to developing hypercapnia
- Hypo-/Hyperthermia – peripheral body temperature does not accurately reflect core temp. Rectal temperature probe inserted at least 10cm into rectum or esophageal probe inserted to level of heart
- Hyperthermia 🡪 larger animals, ketamine
- Hypothermia 🡪 isoflurane
- Vascular access for catheter placement difficult in some
- Arterial blood sometimes obtained from caudal gluteal vein
- Interdigital and jugular v.
Describe immobilization of wild otarrids in the field.
What protocols are recommended, which should be avoided?
Field Immobilization
- Select animals for capture away from water and calm demeaner (sleeping) with least risk of escaping into water
- Darken stabilizers with black permanent marker -🡪 react more to bright colored stabilizer.
- Use nonbarbed and noncollared needles so they fall out as soon as possible
- Pups can be herded to haul out sites or temporary pens. Large animals can be trapped on artificial haul outs then funneled through chutes to squeeze cages
- Stellar sea lions captured with divers, baited nooses and surface capture team in boats
- Telazol by dart associated with risk in stellar sea lions
- Authors report reduced reliability of anesthesia via dart vs hand injection
- Medet+midaz+butor via dart in steller 🡪 safe for sampling and telemetry placement. Smooth induction and full recovery before entering water (reversed atipam and naltrexone)
- If went into water 🡪 dart with reversals and monitor or monitor until spontaneously recovered
What are some of the unique anatomic and physiologic issues with anesthesia in walruses?
What are the most commonly used sites for vascular access.
Describe intubation.
Anatomy and Physiology Issues:
- Prolonged breath holding and low heart rates - “dive reflex”
- Apnea and bradycardia associated with high mortality during immobilization
- Small nostrils with large muscles to close openings during submersion
- Nasal passages - small, no large meatus (prevent water passage)
- Large oral cavity with large, thick tongue and high arched hard palate
- Lower jaw moves between large tusks from upper canine
- Rostral opening to mouth very small
- Difficult to manually direct ET tube into larynx
- Pharyngeal pouch can be inflated to provide buoyancy
- Important to direct tube through larynx and not pouch
Physical Restraint:
- Impractical for most
- Cargo nets for young until 100-150kg BW
- Captive can be conditioned to allow PE, oral exam and thoracic auscultation
Vascular Access
- Dorsal extradural intravertebral vein and caudal gluteal vein
- Epidural venous sinus – identical to placement of epidural needles via lubosacral space in other species
- 16-17g, 8.9 cm tuohy needle
- Caudal gluteal vein – lateral to sacral vertebra, 1/3 distance from femoral trochanter to base of tail
Endotracheal Intubation
- Key: extend the neck to straighten oral-laryngeal axis in sternal recumbency
- Use tusks to prop up the head and extend neck
- Separate rope for each tusk - better access to oral cavity
- Palpate larynx and manual direction of ET tube into trachea is recommended if possible - stylet that is 2x as long as ET tube
- Blind intubation not recommended - often lead to intubation of esophagus or pharyngeal pouch
- Small doses of propofol is helpful for muscle relaxation and unconsciousness to facilitate ET intubation in EIV sinus
Where are the best sites for administration of anesthetics in odobenids?
Describe the monitoring of odobenids under anesthesia.
Drug Delivery/Chemical Restraint:
- Thick skin and insulating fat complicate regional nerve blocks
- Effective if injected around surgical site or on sensory nerves to a region
- Chronic pain management - no recommendation can be made for use of NSAIDs
- Best muscles for IM injections - large muscles of the back (epaxial mm)
- Caudal to last rib and cranial to pelvis on both sides of vertebral column
- Also muscles of front limb - beware of large cervical blood vessels cranial to front limbs
- Sublingual Injection into base of tongue - rapid absorption
- Cardiac and resp support drugs in emergencies especially
Monitoring
- Apnea common - Ventilatory support essential
- End tidal gas (ETCO2) and/or blood gas measurement - efficiency of ventilation
- Apnea - resp and metabolic acidosis, arrhythmias, and poor anesthetic delivery - controlled ventilation and expired gas monitoring essential
- Often immobilized with midazolam+meperidine. Atropine recommended to prevent vagal induced bradycardia.
- IM epaxial or hip with 3-4inch needle
- HR typically 80-100 at onset, slows to 60 as anesthesia deepens. Can visualize heartbeat, auscultate or ECG.
- Pulse ox difficult to position – reflectance probe against oral mucosa or rectum
Describe the use of the following anesthetics in odobenids:
Meperidine
Ultra Potent Opioids
Dissociatives
Propofol
Inhalants
Meperidine:
- Effective sedative and immobilization agent
- Sedation and restraint are moderate without any detrimental effects
- Recommended that atropine be given for bradycardia
Opioids:
- Highly potent opioids - apnea, muscle spasms, rigidity, death
- Difficult to intubate due to muscle rigidity
- Medetomidine + carfentenil 🡪 improved muscle relaxation, still severe respiratory depression
- Apnea prompted immediate reversal of both drugs
- Carfentenil 🡪 muscle twitching, body tremors, muscle rigidity
- Naltrexone given immediately and repeated at end of work time
- Etorphine 🡪 15-20% mortality
- If using potent opioid, you need to have naltrexone
Dissociative:
- Long duration of effect, lack of reversal agent – imperative to prevent partially anesthetized animal from entering water
- Telazol+medetomidine 🡪 low SpO2
- Ketamine+medetomidine 🡪 normal RR, no muscle spasm, smooth and rapid recovery following atipamezole
Propofol
- Small bolus via EIV sinus to provide unconsciousness and facilitate endotracheal intubation.
- Reduces need for higher doses of immobilization drugs, facilitating spontaneous ventilation
Inhalant anesthetics:
- Isoflurane as maintenance is good
- Sevoflurane - uptake and elimination are faster (lower solubility) may provide shorter recovery and faster induction
- Oxygen set at >4L/min
What are some of the most common surgeries performed in pinnipeds?
How is closure unique in these animals?
Surgeries
- Castrations – bilateral orchidectomy with single prescrotal incision and closed technique
- Ophthalmic and dental surgery – most common
- Wound debridement, abscesses – in rehab
- Orthopedic surgery – most are salvage – amputation or arthrodesis
Surgery (CRC 41)
- Tension relieving sutures often requires. Close in multiple layers to prevent dehiscence.
- Most animals allow access to water in days to a week. Varies. Avoid fecal and urine contamination of surgical sites.
- Fracture repair not commonly reported.
- Amputation may be elected for digits or limbs
- May do well even with front or rear flipper amputations.
- Mandibular fractures are common and can be repaired
- Gastric FB occur
- Often incidental findings.
- Many animals will vomit FBs before they pass further in GI tract.
- Surgery may be needed – impaction, perforation
- Urogenital Surgery
- OVH have been performed, similar to canines.
- Castration in male otariids – scrotal testicles. Pre-scrotal incision as with canines.
- Rarely performed in phocids – para-abdominal testicles.
Describe domoic acid toxicity in pinnipeds.
Domoic acid is produced by what organism?
What is the mechanism of the toxin?
What are the acute v the chronic clinical signs?
What are the common lesions on necropsy?
What are the challenges with detecting domoic acid in affected animals?
Domoic acid toxicity
- Amino acid excitatory neurotoxin produced by diatoms- Pseudo-nitzschia (P. australis commonly affects California sea lions)
- DA binds to glutamate ionotropic receptors -> nerve depolarization -> endogenous glutamate release -> activation of voltage gated calcium changes -> cell dysfunction and death
- While most common in CSLs, also diagnosed in harbor seals and northern fur seals
-
Acute neuro abnormalities: ataxia, head weaving, abnormal scratching, seizures, coma
- Often strand in clusters associated with blooms
- Acute necrosis affecting granular cells in dentate gyrus, pyramidal neurons in hippocampus, neurons of amygdala and piriform lobe
-
Chronic neuro abnormalities - intermittent seizures, unusual behavior, vomiting, apparent blindness, may be otherwise clinically normal between neuro events
- Strand individually and may not be associated with specific blooms
- Electroencephalogram abnormalities
- Hippocampal abnormalities on MRI - unilateral or bilateral atrophy
- Eosinophilia, low serum cortisol noted in CSLs
- Brain lesions: hippocampus and parahippocampal gyrus, unilateral or bilateral
- Cardiac lesions: regions of myocardial pallor or streaks along epicardial surface, pericardial effusion, flaccid heart
- Histologic lesions of interventricular septum (earliest at base) and left ventricle
- Acute: interstitial edema, rowing of cardiomyocyte nuclei and vacuolated, occasionally necrosis
- subacute/chronic: myocyte loss and replacement by adipocytes or connective tissue
- Histologic lesions of interventricular septum (earliest at base) and left ventricle
- Reproductive: abortion, premature parturition
- Detect within amniotic fluid, fetal stomach contents, urine
- Abnormal behavior in pups and yearlings with suspected in utero exposure
- DA has a short half life - only present in serum of recently exposed animals - can be detected in feces, serum, urine, gastric contents (tandem mass spectrometry with liquid chromatography

What are some of the most common congenital defects in pinnipeds?
Congenital
- Harbor seals - hernias, skeletal malformations
- Harbor seals can normally have functional patency of foramen ovale and ductus arteriosus up to 6/7 weeks of age - not a congenital affect
- Elephant seals - hydrocephalus, cardiac abnormalities
What is the most common cardiac disease of pinnipeds?
- Myocardial interstitial fibrosis - older CSLs, often males; associated with acute death during anesthesia in addition to myocardial necrosis that can develop with complications in anesthetic events
- Age related arteriosclerosis
- Valvular endocarditis has been reported as well
















