Week 5 ICU Hypermetabolism II: ARDS/ Pulmonary Failure Flashcards
What is ventilation?
Ventilation = respiratory rate (per min) X tidal volume/breath
* Can measure partial pressure of carbon dioxide (pCO2) to determine efficiency of ventilation
* Regulation of breathing : centrally mediated
Define resipiratory failure
This is a general term that describes ineffective gas exchange across the lungs by the respiratory system
* Infection/inflammation of lung tissue
Goals of treatment for respiratory failure
- Preserve and restore LBM
- Maintain fluid balance
- Wean off of ventilator
Respiratory failure effect on Cardiac Disease
Core Pulmonale
* right ventricular hypertrophy and failure due to increased pressure within pulmonary arteries from respiratory failure.
* Treat with oxygen therapy and diuretics to control edema
Protein Requirements for respiratory failure
1-2 g/kg/d
* upper range if cachetic
* lower ranges if overweight or obese
Fluid requirements for respiratory failure
2-3 l/d
* may have to restrict fluid if have CHF or cor pulmonale (usually 35 ml/kg or 25-30 mls/kg depending on age).
* If patients need to be fluid restricted then a TFI of 80-90% of basal fluid requirements may be needed.
Indications for EN nutrition support in respiratory failure
when patient is unable to meet nutritional needs via oral route
* Polymeric feeds are usually fine
Considerations for EN with respiratory failure
- consider if patient has a high risk of aspiration due to reflux or dysphagia or dyscoordination of ventilation (may occur with ++ SOB)
- Consider specialized feeds (eg Pulmocare) with slightly lower CHO intake if acute illness where ++ SOB
PN indications for respiratory failure
PN rarely indicated
* may occur in very acute situations where cannot meet nutritional needs via GI tract; eg serious infection with intractable diarrhea
PN complication with respiratory failure
Central line placement challenging due to ↑ risk for coagulopathy and hyperinflation of line; use with caution
Define sepsis
- Infection: characterized by an inflammatory response to the presence of micro-organisms or the invasion of normally sterile host tissue by these organisms
- Bacteremia: presence of viable bacteria in the blood
Consequences of sepsis
- Can cause a state of hypermetabolism that is more variable than in trauma (clinical condition can change rapidly…within minutes)
- Mortality and morbidity very high
- Leads to impaired immunity (as does malnutrition)
- Severe sepsis is associated with organ dysfunction, hypo-perfusion or hypotension.
When can sepsis occur?
This can occur in either phase of Metabolic Stress
* ebb phase
* flow phase
What is Systemic Inflammatory Response Syndrome?
Two or more of the following:
* Temperature > 38° C or < 36 °C
* Heart Rate > 90 beats/min
* Respiratory Rate > 20 breaths/min or PaC02 < 32 torr
* WBC > 12,000 cells/mm or < 4000 cells/mm3 or > 10% immature or band forms
What is septic shock
sepsis with hypotension, despite adequate fluid resuscitation, along with the presence of perfusion abnormalities that include lactic acidosis, oliguria or acute alteration in mental status
* acute, rapid on-set; sepsis…a little more chronic, may take more time.
Treatment for sepsis
- Need to treat with IV anti-biotics or antifungals
- Treat with blood products (including RBC, fresh frozen plasma), inotropic and vasoactive agents + have the potential for mechanical ventilation
Protein metabolic response during sepsis
Increased protein turnover
* need for gluconeogensis; biosynthesis of acute phase proteins
* Glutamine impt to reduce acidosis
Lipid metabolic response during sepsis
- ↑lipolysis
- ↓oxidation and synthesis
Carbohydrate metabolic response during sepsis
- insulin resistance
- hyperglycemia
Vitamin/mineral response during sepsis
May have changes in nutrient balance of magnesium, zinc, phosphorus and potassium
* Zinc is sequestered in metallothionine system in liver (as is iron)
* Ferritin is an acute phase reactant; therefore get ↑ serum concentrations during sepsis; not reflective of total body iron status
EN nutrition support for Sepsis
EN preferable;
* prevent bacterial translocation from gut but
* exercise caution due to ↓ perfusion to splanchic bed (particularly in septic shock)
PN nutrition support for sepsis
PN is not typically a route of nutrition support.
* ↑ risk for infection
ARDS
Acute respiratory distress syndrome
How is ARDS defined?
Onset of severe acute lung injury characterized by acute hypoxemic (low level of O2 in blood) respiratory failure
What are some characteristics of ARDS?
- Get bilateral radiographic infiltrates with systemic or pulmonary inflammation
- Functional surfactant is lost and get alveolar collapse: shifting of non-oxygenated blood past the collapsed lung
- Finally get pulmonary hypertension due to the vasoconstrictive effects of acute hypoxia (very serious with high morbidity and mortality risk associated with this)
Phases of ARDS
- exudative phase (0-7 day)
- proliferative phase (7-21 days)
- fibrotic phase (>21 days)
exudative phase of ARDS
initial insult - most dangerous (0-7 days)
* Interstitial edema
* capillary congestion
* exudate of airspaces (make need lung drainage)
* sloughing off of alveoloar cells
Proliferative phase of ARDS
Beginnings of recovery (7-21 days)
* Myofibroblast proliferation in airspace and interstitum with mononuclear cell proliferation
Fibrotic phase of ARDS
Scarring/ permanent healing (>21 days)
* Increasing fibrosis
* honey combing and cyst formation
* scarring is trying to help with wound; see permanent places of damage
What P/F ration is indicative of lungs working?
P/F ration <200
Energy and protein nutrition requirements for ARDS
- Energy: 25-30 kcal/kg; could be higher with sepsis (may be as high as 35)
- Protein: 1.5-2 g/kg/d (consider renal function; if impaired may not want to go this high)
Increased if sepsis is present
CHO nutrition requirements for ARDS
Avoid overfeeding with CHO; keep GIR < 5 mg/kg/min
Electrolyte requirements for ARDS
Monitor serum electrolyte carefully
* particularly PO4 Mg and K+; re-refeeding syndrome
micronutrient requirements for ARDS
Ensure micronutrient status
* all are micronutrients are important
* pay close attention to thiamin, antioxidants, pyridoxine and Zn re: infection risk
* Sometimes patients are prescribed antioxidant cocktails consisting of selenium, vitamin C and E and b-carotene (equivocal results)
EN nutrition support for ARDS
preferred if nutrition support necessary
* May need ventilatory support for ARDS for 10-14 days
* Start with Ng
* typical energy dense, lower CHO (isoosmolar, polymeric, HP)
PN nutrition support for ARDS
rarely indicated
* avoid overfeeding at all costs; better to give less so you don’t compromise respiratory function
* Keep GIR at 2-4 mg/kg/min
* Protein requirements: 1.5 g/kg/d (monitor renal function and may need to give less 1.2 g/kg/d)
* Energy: consider cachexia and ebb vs flow phase of stress response; if in acute distress; feed at lower energy intakes of 15-20 kcal/kg
* Keep PN within TFI set by MD; introduce PN cautiously and increase slowly as per Pt outcome
* Electrolyte and fluid management critical
ASPEN guidelines for COVID
- Early EN (24-36 hrs); hypocaloric and advanced slowly to 15-20 kcal/kg actual body weight
- Protein 2-2.5 g/kg/d due to high risk for sarcopenia.
- Recommend continuous feeding rather than bolus. NG or oro-gastric tube.
- Early PN; top off if EN not meeting needs
Define intestinal failure
Gastrointestinal function which is insufficient to satisfy body nutrient and fluid requirements.
* This means individuals have an inability to meet their nutritional and fluid needs
without external sources of fluid and nutrition (IV).
When does intestinal failure require transplantation?
When a patient experiences complete intestinal failure with ongoing significant complications such as infection, liver failure
length of SI
- neonate: 250 cm
- adult: avg. 600 cm (range 260-800 cm)
Defining short gut syndrome by SI length
200 cm viable (adult)
* >50-80% has been lost
SI length requiring lifelong TPN dependence
- adult with intact colon: 60 cm
- adult without colon: 100 cm
- infant with ileocecal valve: 11 cm
- adult without ileocecal valve: 12-25 cm
minimal gut length required for life
What happens in terms of Nutrition when you have Intestinal Failure?
- Malabsorption of macro-and- micronutrients, fluid and electrolytes
- Can become dependent upon IV nutrition for fluid & nutritional needs
- Failure to thrive
- Increased risk for complications due to lack of enteral stimulation (Infection/ organ failure)
- Decreased Quality of Life
What can cause bowel obstruction
- mechanical blockage
- paralytic ileus (impaired motility)
Symptoms of bowel obstruction
higher the obstruction the quicker the symptoms
* fecal matter gets stuck
* vomitting
* hypovolemia (obstruction absorbs fluid)
* may turn malodorous with fecal smell
* abdominal distension
* constipation with failure to pass flatus
* bowel sounds: high pitched at first then silent.
Prognosis for intestinal autonomy (independance)
- Residual small bowel length (More important for adults than children)
- Presence of IC valve: prevent bacterial overgrowth from LI to SI
- Presence of colon: affects intestinal transit and Fluid, electrolyte, energy absorption
- Motility: prevent bacterial overgrowth
- Enteral Stimulation to promote gut adaptation (critical)
Why is residual bowel length more important in children than adults?
children have potential to increase gut length
* favorable long-term prognosis compared to adult for potential intestinal growth after resection
Modes of Nutrition Therapy in Intestinal Failure
- Total Parenteral Nutrition (TPN)
- Enteral + PN + IV hydration
- Enteral + IV fluid support (jejunostomy)
- Enteral (continuous vs bolus feeds)
- Oral diet (with small bowel adaptation)
Medical Management of Diarrhea and Ostomy Output
- Avoid factors that ↑ unabsorbed solute (eg CHO)
- Monitor accurate input and output
- Measure stomal fluid electrolytes (liquid losses include water, sodium, potassium, magnesium, zinc, selenium and bicarbonate)
Types of ostomys
Energy needs for intestinal failure
Increase energy density of diet
* Energy requirements tend to be 25% -200% higher due to severity of malabsorption
* higher if patient experiences liver failure
EN energy management (calories) for intestinal failure
Consider use of nocturnal nasogastric feeding when necessary (po intake < 50% of total energy requirements)
* adults may range from 35-40 kcal/kg
* children and adolescents; 60-100 kcal/kg (dependent upon age)
* Infants: 120-150 kcal/kg
PN energy management (calories) for intestinal failure
PN varies - onyl use when gut not functioning or in presence of severe esophageal varices
* have to be careful NOT to overfeed!
Protein requirements for intestinal failure
1-1.5 g/kg/d
maybe higher depending on extent of intestinal or liver dysfunction
Important considerations with intestinal failure
- Be careful of re-feeding syndrome as most patients with intestinal failure ± liver failure have cachexia
- pre: nutritional TX status affects morbidity and mortality in post-TX period
What needs to be monitored in liver & intestinal failure for nutritional status?
- fat soluble vitamins and others; ensure adequacy (give supplement)
- Albumin; not good marker under these conditions
- Serum and urine electrolytes; fluid and electrolyte status
- Urea; recent protein intake, renalfunction and hydration
- creatinine; lean body mass and renal function
- Liver function tests: AST/ALT, ALP, GGT, Conjugated Bilirubin
- CBC/ Hb, hct MCV; iron status
- ferritin; reflective of iron stores but is also acute phase reactant so in presence of infection or sepsis does not reflect iron status well
Goal of nutritional management with intestinal transplant
promote recovery and optimal nutrition in the Post-TX period and to minimize nutrition related complications of immunosuppressive therapy
Phases of treatment with bowel/liver transplantation
- Acute transplant period (post-operative course: 24-48 hours)
- chronic phase
Major Complications that exists for TX recipients
- Rejection
- Infection
- Side Effects of the medications: increased poor bone health, increased protein turnover and increased risk for sarcopenia and frailty, increased cancer risk.
- Increased CVD complication risk associated with insulin resistance, obesity and increased oral intake
Potential electrolyte complications with Intestinal/Liver TX in the Acute Period
Electrolyte disturbances
* Increased stomal losses and immunosuppression; renal function may be compromised due to high levels of immunosuppressive drugs (these are often nephrotoxic).
* Commonly: serum potassium may be too low or too high; depending on meds
* Magnesium often low due to meds
electrolyte needs in the acute period of intestinal/liver treatment
Meds often means you need to increase delivery; MD to order changes in acute period; RD to monitor.
Energy needs in the acute period of intestinal/liver treatment
varies with individual, gender, coinciding medical events
* Ebb Phase consider 15-20 kcal; kg
* Flow Phase: 30-35 or possibly higher kcal/kg
Potential protein complications with Intestinal/Liver TX in the Acute Period
Induces a stress response so protein turnover increases with
* ↑ biosynthesis of acute phase reactants;
* ↓protein synthesis and
* ↑protein oxidation
* Also corticosteroids (eg prednisone) increase protein turnover
protein needs in the acute period of intestinal/liver treatment
1.5-2 g/kg/d in adults
* Protein needs increase due to losses in stomas, surgical drains
What kind of EN feed would you choose in the acute post-operative phase for intestinal/liver Tx; assuming patient is hemodynamically stable?
All are possible; you need to consider patients TFI, blood work; review medical records for any indications for graft rejection
* Polymeric: lactose feed should be fine; what are they? Would you use a higher protein formula
* May need semi-elemental with MCT oil if still have some malabsorption due to acute rejection of new organ
* What about need for fluid restrictions?
PN in acute period post TX?
Only if GI tract not working within 24-48 hours (in children); 4-5 days or longer (adults)
* Repeated endoscopy will show signs of rejection
* ↑ stomal output form intestinal graft
* persistently high liver functions (ALT, AST, conjugated bilirubin/unconjugated bilirubin) for liver TX
Energy needs in the chronic period of intestinal/liver treatment
30-35 kcal/kg
* unless have chronic rejection; then may be higher
Protein needs in the chronic period of intestinal/liver treatment
1 g/kg/d
* may vary depending on corticosteroid dosing
* Need to consider nephrotoxicity of drugs as well; renal function is often compromised by the drugs
Glucose and lipid complications with Intestinal/Liver TX
- Glucose and Lipid Metabolism; May have chronic insulin resistance (caused by immunosuppressive therapy)
- Hyperlipidemia, insulin resistance, obesity are common long term complications in organ recipients
- Omega 3 therapy helpful to reduce inflammation in organ graft
Chronic nutrition support with intestinal/liver transplantation
Tapering of parenteral/IV support with progression of enteral support
* Slow increase of enteral support- continuous
* Monitor electrolyte & fluid balance
* Monitoring of feeding tolerance (stomal outputs) + nutrient absorption
Clinical variables to consider in cases when considering nutrition support.
- medication effects
- metabolic phase of stress
- other metabolic changes and function
- ventilation/ respiratory status
- GI function
- hemodynamic stability/ instability
- type of injury/ relevant co-morbid conditions
- presence of infection/sepsis
- lab work
- fluid status/ TFI
- transplant type
