Oesophagostomy Tube – Journal Club

Aim

  • To identify the nature and prevalence of complications following o tube placement and whether any cat factors influence this
  • Hypothesis was immunocompromised cats and those that had tubes in place the longest would be the most susceptible to infection

Materials and methods

  • Case selection
  • Placement of o-tube, date of placement, complications, date of removal
  • Exclusion
  • Date of removal was not recorded
  • Data collected
  • Case signalment
  • Body weight
  • BCS
  • Dx
  • Date o tube placed
  • Make of o tube, gauge of tube
  • Antibiotics used
  • Presence and nature of complications
  • Whether discharge was present at the stoma site and the date the discharge was identified at the stoma site and the date the infection was noted
  • Culture and in vitro antimicrobial sensitivity profile
  • Whether the cat had a systemic infection present
  • Whether the cat had a systemic infection present
  • Whether the cat was receiving glucocorticoids or oncolytic agents
  • Whether the cat was discharged from the hospital with the tube in place
  • The date the tube was removed and whether intentionally or not
  • Whether the cat was euthanized with the tube in place or not
  • Calculations
  • Time from presentation to the referral centre to tube placement (days)
  • Number of days from tube placement to discharge being noted around the stoma site injection (where applicable)
  • Number of days that the tube was left in place
  • Discharge defined as secretion from the stoma site which was culture negative or in which cytology did not identify intracellular bacteria or if no culture or no intracellular bacteria identified defined as a secretion that resolved spontaneously without topical or systemic antimicrobials
  • This was not considered a complication if the only finding identified
  • Clinically relevant infection was defined as signs of stoma site inflammation in which bacteria were culture or in which intracellular bacteria were identified on cytology of the discharge or antimicrobial therapy was necessary to achieve clinical resolution
  • Categories of disease
  • Gastrointestinal
  • Hepatic
  • Pancreatic
  • Traumatic
  • Neoplastic
  • Respiratory
  • Cardiac
  • Urogenital
  • Septic
  • Infectious
  • Other
  • If the cat had more than one o tube placed, only the first o tube was included in the study

Results

  • 248 cats
  • Median age 7 years 7 months
  • Median weight and BCS 4kg and 4
  • Most tubes placed on the day of presentation or the following day
  • Type of tube – surgivet, mila , cook or portex
  • Most common tube 19Fr, 14 Fr
  • 162 cats that survived (162/248 65.3%) the tube was in place for a median of 11 days (range 1-93 days)
  • 78/162 (48.1%) experience a complication
  • 86/248 cats that died (34.7%) death occurred at a median of 4 days after presentation and 11 of these cats had a complication associated with their o tube
  • Complications associated with having an o-tube in place reported in 89 cats (35.9%) of all cats
  • The most common complication was dislodgement of the tube
  • Entirely removed by the cat 19.1%
  • Dislodged by the cat necessitating removal 12.4%
  • Dislodge by the cat after repositioning and re-suturing 9%
  • No cat had more than 1 complication recorded
  • Infection associated with the tube was the second most complications encountered in the study 33.7%
  • An additional 45 cats had a discharge at the stoma site that was self-limiting and did not necessitate treatment
  • The median time to stoma discharge as 6 days (range 1-62 days)
  • Additional complications
  • Vomiting in regurgitation of the tube 7.9%
  • Tube blockage whether it resolved or not 7.9%
  • Individual cat complications
  • Temporary laryngeal paralysis
  • Focal oesophageal rupture
  • Irritation of the tube site despite grossly normal appearance of the stoma
  • Displacement of the tube causing a pharyngeal obstruction
  • Inflamed stoma in the absence of infection
  • Dry discharge at the tube site in the absence of infection
  • Mucoid discharge surrounding the tube
  • Sterile necrosis surrounding the stoma site
  • Vomiting following tube placement
  • Anitmicrobials
  • Given to 167 cats while their o-tubes were in place – 85 before tube placement and 82 after tube placement
  • Remaining 81 cats did not receive antimicrobials while their e tubes were in place
  • A single antibiotic was given to 121 cats while 31 cats received 2, 14 cats received 3 and 1 cat received 4
  • An infection was documented after the placement of o-tube in 30 cats
  • 19 had culture performed of which 1 recorded no growth and was diagnosed on cytology and failure to resolve spontaneously
  • 1 organism in 12 cases E.coli n=5, streptococcus canins or beta haemolytic streptococci n=2 , Pasteurella multocida n=2 , enterococcus spp n=1 , staphylococcus n=1 , pseudomonas aeruginosa n=1
  • 3 cats has 2 organisms isolated ecoli and enterococcus spp n=2 , Pasteurella multocida with staph aureous n=1
  • 2 cats had 3 organisms identified strep , enterococcus and E.coli and candida spp , enterococcus and e,coli
  • The remaining cat had 4 organisms cultured methicillin resistant staphylococcus ,e coli Pasteurella multocida and Pasteurella pneumotropica
  • Mila feeding tubes, cats with a discharge at the stoma site and those receiving glucocorticoids or chemotherapy agents had an increased odds of developing a clinically relevant infection necessitating treatment
  • Cats that died had a decreased odds of developing an infection requiring treatment

Discussion

  • Complication rate of 35.8% increasing to 48% in cats that survived to discharge
  • Most frequent was tube displacement followed by a clinically stoma site infection
  • No cats died or suffered from severe morbidity related to the tube that was not remedied by its removal
  • Stoma site infection was the second most commonly encountered complication occurring in 12.1% of cases
  • Most common infections involved commensal organisms rather than primary pathogens or environmental organisms E.coli and Enteroccus spp were the 2 most commonly isolated bacteria these are normal commensals of the GIT tract
  • O-tubes predisposes to infections with opportunistic bacteria
  • The normal antimicrobial protective mechanisms of the skin are bypassed once th tube is in place
  • It also creates a connection between the 2 populations of flora that are naturally separated, altering interactions and potentially allowing overgrowth of certain populations
  • O tube will cause local tissue irritation, precipitated by chronic micro-movements and foreign body reaction
  • Self-trauma secondary to discomfort or irritation, could cause secondary wounds or damage to the tube , gross or microscopic allowing bacteria to colonise more readily and potentially from antibiotic resistant biofilms
  • It is likely that immunosuppression secondary to underlying disease might play a role in development of infection
  • Administration of glucocorticoids or chemotherapeutic medications was associated with an increased odds of developing a stoma site infection
  • Unexpected finding with a higher rate of severity of infections with glucocorticoid or chemo – hygiene
  • Mila tubes higher odds of development of an infection
  • Gauge of tube did not influence the odds of infection
  • But view with caution as tube manufacturer and gauge were not recorded in all patients
  • Cats that died were at a lower risk of o-tube complications including stoma stie infection – cats died after a median time to stoma site infection but median time for infection was 6 days
  • The length of time that the tube was in place whether the cat was discharged home with the tube still place and the underlying disease process were not associated with an increased odds of infection
  • Limitations
  • Retrospective
  • Lack of standardization of tube placement
  • Lack of record keeping
  • Stoma site care not standard

Cats require approx. 40 essential nutrients

  • Cats require higher amounts of protein
  • A lack of enzymatic adaptation to dietary protein levels – rate of protein breakdown does not adjust according to reduced protein intake
  • Typical prey of cats is low in starch and high in protein
  • Protein requirements for a critically ill cats – 60-80g/1000kcal which is higher than the minimum maintenance protein requirement, likely due to factors such as increased protein losses or altered metabolic and inflammatory pathways
  • Thus postulated that the high protein and aa requirements are intended to minimise elan mass catabolism during illness
  • Cats cannot adequately use beta carotene (plant based) as a source of vitamin A and require dietary retinol
  • Cats has a very low delta-6-desaturase enzyme activity, which limits their fatty acid metabolism, therefore arachidonic acid is an essential nutrient
  • Taurine Is also an essential nutrient that is most abundant in animal tissue (esp organs) where as dogs can synthesis from sulfur containing aa
  • Vitamin D is essential in both cats and dogs but cats extract dietary vitamin D more efficiently from animal sources (cholecalciferol) than from plant based ergocalciferol.
  • NB cats are strict carnivores but can’t survive on meat alone (esp skeletal meat)

Feline energy requirements

  • RER is the basal metabolic rate

Physiology of starvation

  • Simple starvation
  • Metabolic response to provide nutrients for basic functions using body reserves
  • Healthy animals without access to food
  • Dietary nutrients are used to meet immediate needs, sparing endogenous fuels stored as glycogen and adipose tissue
  • Excess energy stored as fat
  • When there is food deprivation the use of endogenous fuels is required to maintain body functions
  • Over time there is a shift from using mixed sources (glycogen, protein, fatty acids) to using fatty acids as aa primary fuel source and a simultaneous decease in basal metabolic rate to conserve resources (such as lean body mass)
  • Glycaemia will be maintained via hepatic glycogen (glycogenolysis) and when these stores are depleted, gluconeogenesis, using substrates resulting from the catabolism of adipose (glycerol) and lean tissue (glycogenic aa, lactic acid and pyruvate)
  • Glucose can be recycled – with energy cost – to ensure provision for glucose-dependent tissue
  • Some of these tissues like the brain can adapt to using ketone bodies as an energy source
  • Stressed Starvation
  • Undernutrition is secondary to decreased food intake and altered metabolism associated with disease
  • Hospitalized cats may be in a hypermetabolic state, induced by inflammatory mediators and stimulation of the sympathetic nervous system
  • This can increase energy expenditure and proteolysis, leading t a negative energy and nitrogen balance, with no adaptive reduction in the metabolic rate
  • Despite the effect on energy needs the overall energy expenditure of hospitalized cats is lower than maintenance, likely due to a reduction in physical activity during cage rest
  • However the accelerated loss of lean body mass can negatively affect immune function wound healing and potentially, overall survival
Medications associated with inappetence

Causes of inappetence in cats

  • pain , ileus, stress, dehydration and electrolyte abnormalities , illness, nausea , medications , constipation
  • dysmotility is reported in association with pancreatitis, hepatic lipidosis, electrolyte abnormalities, opioids , primary GIT disease and systemic disorders
  • ileus with fluid and gaseous distension of the bowel causes pain and inappetence as well as fluid sequestration 4
  • normal rates of peristalsis are 4-5 contractions/min for the proximal duodenum and 1-3 contractions/min for the rest of the small intestine
  • stomach should contract 4-5 times/min if it contains some food and less frequently if empty
  • hypokalaemia has been associated with reduced appetite and ileus

Nutritional assessment of the hospitalised cat

  • should be 5th vital assessment (temp, HR, RR, pain)
  • allow informed decision-making in the choice of diet and the need for and type of assisted feeding required and which patients will benefit from early intervention
Assessment tool to identify the need for nutritional support
Potential causes of distress and reduced food intake

Nutritional support of the hospitalized cat : appetite stimulants

  • Oral mirtazapine
  • Higher doses side effects – hyperexcitability , vocalization , tremors
  • Healthy cats half life allows daily administration
  • Some antiemetic properties acting on the 5HT3 receptor
  • Renal elimination – CKD longer clearance therefore give eod
  • Half life prolonged with liver disease (ALT >200 or TBil >1mg/dl)
  • When behavioural side effects are noted 50% dose reduction is recommended
  • Transdermal mirtazapine
  • Clinical trail in 177 cays with >5% unintended wt loss demonstrated that 2mg applied daily to the inner ear pinnae for 14 days resulted in significant weight gain
  • Most common adverse effect was erythema of the pinnae
  • Cats with kidney disease experienced similar therapeutic efficacy without an increase in behavioural side effects therefore daily dosing appears appropriate
  • Slower onset of action as flatter drug concentration curve and lower peak serum conc
  • Consider perfusions and body temp as this can affect absorption
  • Capromorelin
  • Ghrelin receptor agonist
  • Acts directly as an orexigenic compound, stimulating appetite in a similar fashion as ghrelin while also acting to stimulate growth hormone and IGF-1
  • CKD cats with >5% unintended wt loss demonstrated that 2mg/kg PO q24 hour for 56 days resulted in significant wt gain
  • Contraindications with acromegaly caution with DM and hyperglycaemia
  • Transient bradycardia and hypotension have also been documented in feline patients therefore not recommended that this medication be used in patients with significant systemic compromise which likely precludes the use in hospitalised patients
When to consider placing a feeding tube

Feeding tubes

  • NO or NE tubes
  • Obstruction and dislodgement are most common complications occurring ing 8-13% of cats
  • O tube
  • Complications – stoma site infection and tube dislodgement
  • Before implementation of a feeding plan , cats should have been rehydrated , have had any major electrolyte and acid base disturbances addressed and be cardiovascular stable
  • Maintenance of normotension is desirable prior to enteral feeding in humans as enteric vasodilation could further reduce systemic blood pressure and similar is likely the case in feline patients
  • Enteral nutrition stimulates G motility , enteric blood flow and local immunity , activates neuroendocrine pathways , promotes a favourable microbiota , reduces oxidative stress and imparts trophic effects on mucosal epithelium thereby supporting enteric barrier function
  • Even when patient cat only tolerate small amount enterally as this will help
  • In growing animals once stabilised energy targets will need to exceed RER – kittens may require 200% RER to support growth
  • Cats recovering from particularly catabolic conditions Eg thermal burns, large exudative wounds may also have energy requirements >200%
  • Once feeding full RER and provided there are no complications the total maximum volume per bolus feed for a cat ranges between 5 and 15ml/kg if feeding via a CRI rates between 3 and 8ml/hr

Refeeding syndrome

  • Characterized by neurological signs (depression, coma) , systemic weakness, haemolytic anaemia , glycaemic dysregulation and severe electrolyte abnormalities (eg hypokalaemia, hypophosphatemia, hypomagnesaemia) due to insulin derived glucose uptake
  • Thiamine deficiency may also contribute to neurological signs
  • IF refeeding syndrome is suspected, feeding should cease until the patient is stabilised and feeding plan adjusted to avoid worsening of this syndrome
  • Id at risk patients is important and included cats that have been missing and a complete lack of food intake, are severely debilitated with significant body condition loss or those with electrolyte abnormalities prior to commencing feeding
  • Prevention of refeeding in this patients should include feeding no more than 20 % RER on day 1 and slowing increasing the proportion of RER over 4-10 days depending on clinical response
  • Empirical supplementation of phosphate at 0.01-0.03mmol/kg/hr , potassium at 0.05mEQ/kg/hr and Mg at 0.01-0.02mEq/kg/hr for the first 24 hours of therapy provided the patient doesn’t have electrolytes values above the reference range
  • Thiamine can be administered prior to feeding (25mg total dose SQ or IM ) and repeated daily until signs resolve
  • Enteral nutrition may preserve gut integrity, minimize bacterial translocation , improve the immune response and attenuate the release of inflammatory mediators

Aim

  • Compare continuous to intermittent feeding at delivering prescribed nutrition in hospitalized canine and feline patients
  • Because intermittent feedings allow for fewer interruptions of nutrition due to diagnostic and therapeutic procedures out hypothesis was that intermittent feeing would result in greater delivery of prescribed nutrition than continuous feeding
  • If true this difference could later the way clinicians prescribe feedings to their patients
  • The secondary aim was to determine the frequency of GIT complications associated with enteral nutritional support

Materials and methods

  • Dogs and cats with NE and or NG tubes between 2002 and 2007
  • Inclusion if NE feeding tube placement was documented in medical record and the tube was used for enteral nutrition for a min of 24 hours
  • 24 hr periods of nutrition were recorded for each patient
  • 24 hr periods in which the patient voluntarily ate , received concurrent parental nutrition or received both intermittent and continuous feeding were excluded
  • Other type of feeding tubes e=were excluded because the caloric content of the food delivered through these tubes was often impossible to determine from retrospective review
  • All patients received 1 kcal /ml veterinary liquid diet thru the NE tube
  • Date – age, species, total days in hosp, total days of enteral nutrition provided via NE, intermittent or continuous method of feeding and frequency of GIT complications
  • The number of calories prescribed for each 24 hr period and number of calores delivered for each 24 hour period were calculated from the medical record . any interruption or discontinuation of enteral nutrition was recorded
  • The % of prescribed nutrition delivered (PPND) was calculated as a number of calories delivered in 24 hr period divided by calories described
  • IF the patient received nasoenteric feeding for >1 day then the mean PPND per day was calculated on a per patient basis
  • The number of 24 hour periods in which PPND equalled 100% was also recorded
  • Frequency of gastrointestinal complications was calculated on a per patient basis

Results

  • 91 animals , 205 days (24 hr periods) of NE feeding
  • 37/91 Dogs 40.7%
  • 54/91 cats 59.3%
  • Dog age range 2months to 14 years median 8 years
  • Cats 1 yr to 16 years with median age of 8.5yr
  • Median number of total days in hosp for all patients was 8 days
  • Median number for enteral nutrition was 2
  • 56(61.5%) of the 91 patients were fed continuously and 35(38.5%) of 91 were fed intermittently
  • 33/54 cats were fed continuously, and 21/54 cats were fed intermittently
  • The median PPND was not significantly different between patients fed continuously 99.p% and patients fed intermittently
  • Feline patients received a median PPND of 100% range 47.9-133.1%
  • Continuously fed cats received 100% 47.9-100% of prescribed nutrition and intermittently fed cats received 100% (62.5-133.1% of prescribed nutrition
  • Continuously fed animals received 100% of their prescribed nutrition which was not significantly different from intermittently fed animals who received 100% of their prescribed nutrition on 51 out of 87 days (58.6%)
  • 29% of patients vomited during enteral nutrition, 26% had diarrhoea , 5% of patients regurgitated
  • 30.7% of patients that experienced vomiting during enteral nutrition were vomiting in the 24 hours prior to starting enteral nutrition
  • 50% of the patients with diarrhoea recorded had diarrhoea in the 24 hours prior to enteral feeding
  • No patients with regurgitation during enteral nutrition had regurgitation prior
  • The frequency of GIT complications in each grp species and method was not significantly different
  • Both grps has 28.6% vomiting and continuously fed grp had 25% Diarrhoea and the intermittently fed grp had 28.6% diarrhoea
  • 7.1 % of continuously fed grp had regurg and 2.9% of intermittent fed regurg
  • Dogs had higher incidence of regurg and diarrhoea than cats
  • All 5 patients that regurg were dogs
  • Out of the 205 days of enteral nutrition the delivery of nutrition was stopped 26 times due to vomiting
  • Regurg interrupted feeding twice and diarrhoea once
  • Other reasons for stopping feeding include dislodgement of naso-enteric tube, surgical procedure, diagnostic procedure , high residues , clogged tubes, blood transfusion , dyspnoea, hypersalivation

Discussion

  • Study shows that suggest that the method of nutrition delivery via naso-enteric tubes does not affect the PPND to veterinary patients
  • In this study the subjects received a median of 97% of prescribed calories regardless of the feeding method used
  • No difference in GIT complications rates are found between patients fed continuously and patients fed intermittently

Definition – multiple metabolic derangements most notably hypophosphatemia, hypokalaemia, hypomagnesaemia, thiamine deficiency , altered glucose homeostasis and fluid shifts are also common

Thought to occur due to rapid shift between catabolic and anabolic metabolism that occurs in response to insulin release assisted with refeeding

This increased intracellular demand for phosphorus, potassium and magnesium causing a critical decline in their circulating concentrations,,

Cellular thiamine demand also increases in response to refeeding as it acts as a cofactor for enzymes such as pyruvate dehydrogenase and alpha ketoglutarate dehydrogenase

Total body reserves of potassium, magnesium, phosphorus, and thiamine are already depleted in states of chronic starvation so the sudden increase in demand creates a marked imbalance with clinically apparent deficiencies

Both impaired glucose tolerance and hypoglycaemia are described in people and in cats with RS

In people this combination of abnormalities is often associated with neurological, cardiovascular , gastrointestinal and haematological abnormalities including tremors, encephalopathy, arrhythmias, heart failure, anorexia vomiting and haemolysis -> Multiorgan failure and death can occur

Usually develops 2-5 day after nutrition has been reinstated but can be seen within hours or up to 10days post

Aim

  • Describe the characteristic clinicopathological findings associated with starvation associated with RS in 11 cats to better characterise disease presentation and outcome

Materials and methods

  • 2013-2019
  • Included
  • there was a risk factor for development of refeeding such as severe weight loss or emaciation following a period of presumed starvation
  • They were documented as hypophosphatemia or had a delta phosphorous exceeding a 30% reduction during hospitalisation following refeeding
  • They had one or more of the following abnormalities documented: hypokalaemia; hypoglycaemia or hyperglycaemia and
  • They were treated in the basis of clinical diagnosis of RS
  • Cases were excluded if their medical records were incomplete
  • Data – signalment, BCS, length of presumed starvation and % bwt loss (calculated using the last recorded weight in each cat hx prior to starvation and their wt on admission )
  • Date of refeeding was taken as the day of the first documented alimentation after starvation
  • Clinic path data
  • Delta phosphorus was defined as the max drip in phosphorus documented after refeeding
  • Delta sodium was defined as the highest sodium minus the lowest recorded sodium
  • The initial caloric target was defined as the first documented, intentional, proportion of RER delivered during hospitalization
  • Tachycardia >240, bradycardia <140 , hypertension >180mmHg , hypotension <90mmHg

Results

  • 11 cases
  • Cats all in good health prior to going missing
  • Median time missing was 6 weeks (3-104 weeks)
  • Mean % wt loss of 46% +/- 7%
  • All cats ate voluntarily within 2 days of being found
  • Phosphorus
  • No cats were hypophosphatemia on initial evaluation 8/11 developed during hosp with lowest phosp at median of 5 days (range 1-13day) after refeeding
  • The median delta phosp was -47% +/-9% occurring over a median of 1 day
  • Phosp was supplemented intravenously over 6+/- 3 days
  • Potassium
  • Mean lowest plasma potassium conc of 2.6+/- 0.4mmol/L occurred a mean of 7+/- 6 days after refeeding and cats were supplemented with potassium IV for a median of 7 days (4-19d)
  • Glucose
  • 10/11 cats ere hyperglycaemic during hosp and 7/11 cats were hypoglycaemic
  • Hypo – all received dextrose supplementation for a mean 3+/- 2 days
  • Sepsis was considered to be a contributory cause of hypoglycaemia in one cat
  • Magnesium
  • 10 cats received IV mg supp for mean of 6+/- 3days
  • Thiamine
  • All cats received
  • Ranged between 25 and 100mg daily with a mean length of supplementation as a continuous rate infusion for 3 and 9 days in cats 9 and 11
  • Cardiovascular – all cats , most frequent hypotension n=6
  • GIT – all cats – most inappetence after initial appetence n=9 ,
  • Neurological – 6 prior to refeeding , most cats displayed vision loss n=4 , 8/11 cats displayed new or progressive neurological deficits after refeeding including mentation changes n=6 and cerebellar dysfunction n=4 . In all surviving cats all neurological clinical signs had resolved at discharge
  • No cats were anaemic at presentation with median PCV 29% (range26-44%). All cats became anaemic with the lowest PCV documented a mean of 8+/-5 days after refeeding
  • 7 cats required blood transfusion a mean of 8+/-6 days after refeeding
  • All cats ate voluntarily initially, with 4 cats eating entirely voluntarily throughout hosp
  • 4 cats received additional parental nutrition and 4 feed by feeding tube
  • The median caloric target in hosp was 10% (range 5-40%) where delivery of 100% RER was achieved intentionally n=9 , it occurred 13 +/- 5 days after initial refeeding
  • 8/11 cats survived to discharge
  • 1 cat died and 2 euth
  • Surviving patients were hospitalised for a mean 14 +/-4 days
  • The presence of AKI was associated with non-survival, and maximum bilirubin conc was significantly higher in non survivors
  • ALT conc, delta phosp, delta Na2+ had no association with outcome

Discussion

  • Protein catabolism during starvation progresses through 3 phases: rapid initial depletion; a subsequent more gradual phase during which lean muscle mass is preserved in favour of fate mobilization and ketone body production and a final preterminal rapid depletion of body protein.
  • There appears to be a point of no return after which a complete recovery is not possible, usually during or after the second wave of protein catabolism
  • Death is likely to occur when protein loss reaches 50% of normal
  • 3/11 cats in this study had lost >50% of their body weight, 2 of which survived to discharge; it appears that cats can survive after 50% weight loss
  • A delta phosp decrease of -30% or more in this current study was deemed significant based on previous use and similar absolute or relative reductions utilised for diagnostic purposes. The time scale to lowest phosphorus after refeeding was 5 days range 1-13 days suggesting that hypophosphatemia may develop acutely or later in hospitalization. However, it is possible that renal phosphate loss secondary to IVF may contribute to hypophosphatemia
  • Hypokalaemia observed in RS is attributed to transcellular movement superimposed on chronically reduced intake
  • Hypokalaemia may cause derangements in electrochemical membrane potentials including delayed ventricular depolarization, prolongation of action potentials and increased automaticity , potentiating the development and persistence of cardiac arrhythmias of both ventricular and supraventricular origin.
  • All 3 non survivors has specific arrhythmias documented in this study
  • 3 cats in this study displaced cervical ventrofelxion despite normal or only marginally low plasma potassium conc at the time. This was potentially attributable to thiamine deficiency.
  • Thiamine is a key coenzyme in the metabolism of CHO and supply often becomes deficient after refeeding owing to increased cellular demand
  • The inhibition of CHO metabolism in a thiamine depleted state can cause energy deficits, neuronal dysfunction and necrosis affecting multiple sites including the oculomotor, vestibular and lateral geniculate nuclei
  • Reported clinical signs included vestibular ataxia, mentation changes, cervical ventroflexion and mydriasis with absent menace reflex with potential regression to coma and death
  • Absolute confirmation of thiamine def is difficult so a presumptive diagnosis is often made based on clinical signs and response to supplementation
  • Hypophosphatemia has been linked to impaired glucose homeostasis in both hyperglycaemic and normoglycemic states and is thought to be a consequence of diminished tissue sensitivity to insulin
  • CHO provision and critical illness may pit cats at a greater risk of hyperglycaemia
  • In this study both hypo and hyperglycaemia are seen
  • Persistent Hypoglycaemia include excessive insulin secretion minimal capacity for glycogenolysis or sepsis
  • Magnesium deficits are often a consequence of reduced dietary intake with concurrent excessive git or renal losses but are common in RS owing to depleted reserves and a sudden increase in demand for Mg
  • Hypomagnesaemia can cause ventricular and supraventricular arrhythmias, seizures and hypertension
  • Hepatic injury in refed patients is due to aurophagy during starvation or lipidosis in the refeeding
  • Haemolytic anaemia is possible n RS as a consequence of decreased intra-erythrocyte ATP conc due to phosphorus depletion
  • Glycolysis is only method of erythrocyte ATP generation , multiple steps of which are stimulated by phosphorus
  • ATP depletion causes increased cellular fragility , shorter erythrocyte lifespan and subsequent haemolysis , although clinical evidence of this is uncommon
  • Cats are thought to be prone to severe hypophosphatemia associated haemolysis in conjunction with having haemoglobin this is particularly vulnerable to oxidation , denaturation and subsequent Heinz body formation and once formed Heinz bodies increase erythrocyte fragility
  • Complications associated with enteral feeding are not rare and range from 13-71%
  • Most common complications associated with the use of o tubes are infections of the stoma site and tube dislodgement
  • NE tubes – dislodgement, diarrhoea

Aim

  • describe the use of feeding tubes in a population of sick cats with appetite disturbances
  • recorded the underlying disease process type of tube used (NE or O tube) and the associated complications
  • report the clinical outcomes (survival and return to voluntary food intake) in this population

Materials and methods

  • 2015-2020 for at least 24 hrs
  • Recorded signalment, duration of anorexia, BW, BCS, PEX , bloods, dx , type of feeding tube , concurrent oral administration of mirtazapine, occurrence and nature of any complications , time from onset of anorexia/hyporexia to presentation at the uni in days , time from presentation at uni to feeding tube placement , time from feeding tube placement to spontaneous return of appetite and total duration of feeding tube utilisation
  • Appetite disturbance was qualified as anorexia or hyporexia
  • Anorexia – complete loss of appetite and hyporexia to partial loss of appetite
  • Return to voluntary food intake refers to as soon as the cat started to eat spontaneously even if the RER was not achieved
  • Cats with voluntary food intake were divided into 2 groups <50% of RER or >50% of RER
  • Disease groups – GIT , hepatic, pancreatic, triaditis , neoplastic, respiratory, cardiac, urogenital , haematological endocrine, respiratory cardiac, infectious
  • Neoplastic if cat could not be entered into the above categories
  • Other if disease not classified, non dx was unknown or if 2 disease processes most likely to contribute to inappetence
  • When body appetite disturbance was <5 days the amount of food provided was progressively increased to reach 100% of RER after x days with x corresponding to the number of days of anorexia
  • When anorexia had been >5 days the RER was gradually increased until full RER at day 5
  • 4-5 meals per day varied with cats tolerance

Results

  • 112 cats with 118 tube placements 6 cats included twice at 2 visits
  • Median age was 9 years , BW 3.8 kg median BCS 4/9
  • 83% had an NE tube placed and 17% an o tube
  • Of the cats with o tube 65% had previously been managed with NE tubes
  • Median time of appetite disturbance prior to admission was 7 days
  • Main biochem abnormalities are increased ALT 65%, hypoalbuminemia 48%, hyperbilirubinemia 59% , anaemia 49% , hypokalaemia 41% and hyperglycaemia 41%
  • Main disease GIT 13.5%, hepatobiliary 11% and upper urinary tract in 11%
  • BCS was significantly lower in NE tube grp
  • NE grp -digestive 15.3% and upper urinary tract 12.2%
  • O tube hepatic 50% and upper resp tract 30%
  • Complications overall occurred in 18.6%
  • NE complications 15%
  • O tube complications 43%
  • O tube after NE tube complications 31%
  • Spontaneous return of appetite before feeding tube removal occurred in 56/118 cases 47% including 50% cases in NE grp and 35% in the o group
  • Median time before return to voluntary food intake 3 for whole population NE was 3 days and O tube was 14 days
  • The amount of food of ingested was recorded in 48 cases for the return of voluntary food intake
  • <50% in 46% and >50% in 54%
  • 33% of cases received mirtazapine but not associated with return to voluntary food intake or amount ingested
  • The decision to remove the tube occurred in 75% of cases the other 25% died or were euth
  • Global population time to removal was 5 days , 4 days for NE grp and O grp 33 days
  • Of those 75% of cases with tube removed 98% survived to discharge and the survival rate was 72.9% for the 112 cats included and did not differ between the NE and the o tube groups
  • Survival was similar among disease categories
  • Resolution of anorexia was positively associated with survival
  • Of the 32 cases that survived to discharge that did not experience voluntary food intake before tube removal follow up was available for 12 37.5% return to appetite 66.7% in median time of 2 days and last 4 remained anorexic 33% – 2 were euth an 2 another tube placed within 72 hours

Discussion

  • Complications 18.6% of cases
  • Spontaneous food intake occurred in half the population before the tube was removed
  • Large population survived to discharge 72.9%
  • When return to voluntary intake was observed 54% of cats ate >50% RER
  • Time before spontaneous food intake was significantly shorter in NE grp
  • Survival did not depend on disease tube type but was positively associated with resolution of anorexia
  • Median BCS and body weight were significantly higher for cats in o tube grp – hepatic lipidosis??
  • Duration of appetite disturbance did not alter between groups – more likely tube was chosen over other parameters such as BCS
  • Voluntary eating occurred in 48% of cats while the feeding tube was in place
  • Quantity of food <50% RER 46% and >50% RER in 54%
  • Mirtazapine did not appear to act on qualitative return to voluntary food intake nor quantitively ie <50 r >50 % RER ingested
  • Complications overall 18.6% , NE 15% – removal most common , o tube complications was 43% – stoma site infection 14.3% and partial dislodgement or complete removal (28.6%)

  • Means to maintain hydration, maintain adequate nutrition and facilitate medication
  • Adequate nutrition improves QOL
  • Compared with adult maint diets CKD diets
  • Reduced protein , phosphorus and sodium content
  • Increased potassium and B-vitamin content
  • Increased caloric density
  • Neutral effect on acid base balance
  • Increased omega-3/omega-6 polyunsaturated fatty acid ratio
  • Hyporexia secondary to CKD is encountered most commonly in the latera stages of the disease but may occur at any point in the course of progressive CKD
  • Factors contributing to anorexia in feline CKD
  • Metabolic
  • Uremic stimulation of vomiting centre
  • Hypokalemia
  • Dehydration
  • Mineral and bone disorder
  • Metabolic acidosis
  • Anaemia
  • Uremic gastritis
  • Hyperphosphatemia
  • Food feeding altered taste and smell
  • Force feeding
  • Sudden diet change
  • Medication intolerance
  • Food aversion
  • Oral lesions/dental disease
  • Offered small frequent meals , gradual diet changes typically over 2-4 weeks
  • Oral ulcerations can reduce intake – chlorhexidine containing oral rinses (not dental formulation as often contain zn gluconate and may cause inadvertent zn toxicity in renal disease )
  • Use of mirtazapine
  • Maropitant – NK1 receptor antagonist and inhibits vomiting via peripheral and centrally mediated effects
  • Most cats with IRIS stage 3 and 4 fail to achieve caloric adequacy and maintain a stable body weight with ad libitum feeding of an appropriate therapeutic renal diet
  • These cats also generally fail to maintain appropriate hydration
  • Proactive intervention with an E tube combats excessive catabolism , helps prevent loss of lean body mass, and facilitates the establishment of a normal body composition
  • E tubes allow for long term provision of nutrition , hydration and medications to facilitate all aspects of management of CKD
  • Occasionally patients with feeding tube esp dogs will develop hyperkalaemia
  • CKD cats have decreased ability to excrete potassium load because of declining aldosterone levels and or a decrease in distal tubular flow
  • Hyperkalaemia may develop in patients receiving diets that are formulated with a high potassium content esp if also receiving an ACEI or ACE receptor blocker
  • Persistent moderate hyperkalaemia usually responds readily to a reduction in dietary potassium and or the judicious use of a loop or thiazine diuretic precluding the coexistence of hyponatremia , which often develops with feeding a therapeutic renal diet

Patient Stories

Our commitment to feline health is best seen in the stories of the cats we’ve had the privilege of treating. These journeys highlight the dedication, expertise and compassion that drive us.

Each patient faced unique challenges, and it was our honour to offer high-quality care and help them regain strength and happiness. We value the deep bonds with cats and their owners, knowing the difference we make in their lives.

Tango Triumphs Over FIP

At 5 months old, Tango was diagnosed with Feline Infectious Peritonitis (FIP). Once considered a fatal disease, the introduction of new treatments has significantly boosted the survival rate.

Toffee Survives Tick Paralysis

Toffee faced a frightening battle with tick paralysis and aspiration pneumonia, she was rushed to AES when her owners noticed her vomiting, breathing difficulties and trouble walking.

JJ & the Lily – a close call

Mischievous JJ had a close call when he ingested part of a lily—an extremely toxic plant for cats. Thanks to the quick actions of his owner, Sophie, a VSS vet nurse, JJ made a full recovery.

Han’s Hip Fracture Surgery

Han presented after limping on his hind leg for two weeks following an accident at home. An X-ray revealed a fractured growth plate in his hip, requiring surgery to repair the injury.

Coco and Kidney Troubles

Coco stayed with us at CSS while recovering from a nephrectomy (the surgical kidney removal). After months of unsuccessful treatment for a ureteral obstruction, this became necessary.

 

Contacting Us

Pet Owners
If you would like to talk about treatment for your cat, call us on 1300 228 377 or fill in the form.
In an emergency, please contact your local vet.

Vets and Nurses
To refer a patient or book a telehealth consultation please call us on 1300 228 377, book through the portal or fill in the form. For advice calls, please see the guidelines here.

Monday-Friday: 8 am-6 pm
Saturday/Sunday - Closed

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