General ICU Concepts

Acute Inhalational Injury

• See ICU>Airway>Burns

Anaphylaxis

• See Allergy-> Anaphylaxis

Hypertensive Emergencies

• See Cardiology>Hypertension

Alcohol Toxicity

• See Toxicology --> Alcohol

Stress Ulcer Prophylaxis

• Physiologic stress of being in ICU causes poor blood flow to gastric mucosa, and can cause mucosal breakdown and gastric ulcers.
• Erosions of gastric mucosa occurs in 75-100% of pts within 24hrs of ICU (most silent, some bleed).

• Table 2.1: Indications for Stress Ulcer Prophylaxis
  Any Of Following OR..	...  ≥2 of following
  1.  Mechanical Ventilation >48hrs 2.  Coagulopathy    Plts < 50,000/mL or    INR > 1.5 or    PTT > 2x control 3.  History of gastritis/ PUD/prior GI Bleed	1.  Hypotesion 2.  Severe Sepsis 3.  Severe Head Injury 4.  Multisystem Trauma 5.  Renal Failure 6.  Hepatic Failure 7.  Burns > 30% of body surface

• Other risk reduction methods:
  • Enteral feeds (effective to prevent erosions)
    • Usually feeds is good enough prophylaxis except if coagulopathy, hx of bleeding from gastritis/PUD, active PUD.
• Prophylaxis:
  • H2 blockers
    • Famotidine (lasts 10-12hrs [20mg q12h, renally adjust)
      or Ranitidine (6-8hrs [50mg q8h, renallly adjust])
    • Effect diminished with repeated use.
    • Adjust for renal failure!!!
      • excreted unchanged in urine, accumulate to cause neurotoxicity (confusion, agitation, seizures)
  • PPI
    • More effective acid suppressors than H2 blockers + no tachyphylaxis (unlike H2B)
      • However, not studied as much for stress ulcer prevention.
    • PPIs indicated following UGI bleed (limited experience in stress ulcer prophylaxis)
    • Options: (both IV)
      • Omeprazole IV [80mg daily, if just bled then do 8mg/hr x1-3d]
      • Pantoprazole IV [40mg daily, + 8mg/hr x1-3d]
  • Sucralfate
    • Aluminum salt of sucrose sulfate --> Cytoprotective agent forming barrier over mucosa.
      (pH not altered)
    • Given as liquid slurry through NG tube
    • Reduces absorption of: warfarin, digoxin, fluoroquinolones, phenytoin, ranitidine, tetracycline, thyroxine (give 2h before sucralfate)
    • DO NOT use in hypophosphatemia
    • TRIAL: Cook et al (1998): Sucralfate vs. Ranitidine --> both effective agents (ranitidine is 2.1% fewer episodes of bleeding, but risk is <5% anyway).  Sucraflate = less pneumonia.
      • Therefore: be careful with ranitidine, pneumonia = higher mortality than GI bleed.
• Risks:
  • Increased risk of pneumonia with stress ulcer prophylaxis

Fever

• Common in ICU:

  • Cause	Types
    1.  Major Surgery	Post-Op Fever (40% of post-op) Malignant Hyperthermia
    2.  Other Procedures	Hemodialysis Bronchoscopy (usually 8-10h later)
    3.  Drugs	Drug Fever (allergy or infusion-phlebitis) NMS
    4.  Infarctions	Bowel (Fever and Lactate are often only signs) Cerebral Myocardial
    5.  Transfusions	Erythrocytes, Platelets
    6.  VTE	- Can be febrile for weeks.
    7.  SIRS
    8.  Iatrogenic

NG Tubes

• Can be used up to a few weeks (before esophageal erosion + othe issues)
• Inserted into nares and advanced blindly into the stomach.
• Distance to advance measured from nares-->ear lobes --> xiphoid process (50-60cm)
• 1% of the time, NG tubes ends up in the lungs.
• Placement:
  • Previously thought that duodenal placement is better (less aspiration risk), but new research --> risk of aspiration is equal. 
• Starting feeds
  • First check the gastric residual volume (aspirate from tube).
  • if < 150ccs --> start feeds
  • if > 150ccs --> wait 2 hours, and try again
    • If still > 150, two options:
      • advance NG tube to duodenum (preferred)
      • start metoclopramide 10mg IV, and check gastric residuals in 2 hours (usually doesn't work)
  • Studies show that full feedings can be started immediately (in the past slowly tapered up feeds).
  • Frequent side-effect is diarrhea - 30% of pts (esp in sorbitol preparations). 

Heat Str​oke

• Failure of body's thermoregulatory system, which may be overwhelmed by environmental conditions.
• At risk:
  • elderly
  • dehydration conditions (diuretics, anticholinergic medications commonly culprits).
  • athletes, military recruits (exercise strenuously in hot weather).
• High mortality rate (as high as 60% depending on degree of hyperthermia and EOD).
• Management:
  • Cool to normal body temperature
    • Ice packs, evaporative cooling most effective.
    • If SEVERE: can attempt cold gastric or peritoneal lavage can be attempted.
    • Benzodiazepines to decrease discomfort and shivering.
  • Do not respond to central anti-pyretics (tylenol, ibuprophen)

Malignant Hyperthermia

• Reaction to certain drugs
  • Inhaled anesthetics (particularly Halothanes + others)
  • Depolarizing neuromuscular blockers (succinylcholine)
• Mechanism:
  • Markedly increased intracellular calcium, increased cellular metabolism, sustained muscle tetany
  • Susceptibility is inherited
  • Mortality rate ~10%
• Presentation:
  • (all typically present immediately post-exposure to trigger, but can be delayed)
  • Previous exposure without a reaction DOES NOT eliminate risk.
    • Severe muscle rigidity
    • Masseter spasm
    • Hyperthermia up to 45°C (113F)
    • Cardiac tachyarrhythmias
    • Rhabdomyolysis.
• Treatment
  • IMMEDIATELY upon signs.

1. Stop triggering agent.
2. Fluids
3. Cooling
4. Dantrolene  (muscle relaxant - prevents release of Calcium from scarcoplasmic reticulum)
   1-2 mg/kg IV bolus + repeat q15m PRN to a total dose 10 mg/kg --> then 1mg/kg IV QID x3d to prevent recurrence
   • Give q5-10min until hyperthermia and rigidity resolve. (reduces mortality 70% --> 10%)
   • Can also prevent recurrence if given before trigger
   • High doses can cause hepatocellular injury

Neuroleptic Malignant Syndrome

• Idiosyncratic reaction to neuroleptic antipsychotic agents
• Presentation
  • Muscle rigidity
  • Fever (** Required ** - distinguishes from dystonic reactions to antipsychotics)
  • Autonomic dysregulation
  • Delirium (very common!)
  • (Often FARM mnemonic used: Fever, Autonomic instability, Rigidity, Mental status change)
• Triggers:
  • Any Dopaminergic Agents
    • Antipsychotics (Haloperidol {most potent- worst}, clozapine, olanzapine, risperidone, etc..)
    • Anti-emetic: Metaclopramide, droperidol, prochlorperazine
    • CNS Stimulants: Amphetamines, Cocaine
    • Other: Lithium, TCA's
  • However ALL neuroleptics associated with this
  • Discontinuation of high-dose Parkinson's medications.
• Often occurs at the time of starting medication or rapid dosage escalation.
  • Occasionally reported to occur after years of use.
• Risks:
  • Men > Women
  • IV > PO
  • Dehydration concominant
  • Association with lithium use (controversial)
  • Can occur in Parkinson's Disease when high-dose medications stopped abruptly.
• Treatment:

1. Stop neuroleptic agent.
2. Maintain BP stability (fluid volume)
3. Lowering Elevated Temp
   • Benzodiazepines for agitation.
4. Dantrolene + Bromocriptine
   • Can be used, but evidence is WEAK.
   • Dantrolene tried at IV 2-3mg/kg (repeat every few hours as needed to total 10mg/kg/day)

• Recurrence is variable and unpredictable
  • After recovery, can restart neuroleptics after 2 weeks wait, at a lower dose, lower potency agent.
  • Avoid lithium therapy and dehydration, monitor for recurrence.

Serotonin Syndrome

• Symptoms;
  •  

Pain, Anxiety, and Delirium

• Pain, anxiety, and delirium are common, contribute to patient suffering..
  • Research shows that pain/anxiety/delirium contribute to mortality and morbidity of ICU patients.
• Delirium:
  • Hyperactive, hypoactive or mixed (alternating agitation and lethargy)
• Evidence supports routine protocol-based management.
• Use objective measures and frequent reassessments:
  • Pain: Visual analog pain scale
  • Anxiety: Richmod Agitation Sedating Scale (RASS)
  • Delirium: Confusion Assessment Method (CAM-ICU)
• Intermittent dosing is preferred, but if continuse infusion used:
  • Frequent reassessments
  • Daily interruption of sedation for reassessment.  ---> decreases ventilator time, shortens ICU stay.
• Haloperidol is suggested for delirium (no FDA-approved medications for delirium)

ICU - Acquired Weakness

• 50% of patients with prolonged critical illness develop weakness (worse than explained by deconditioning).
• Types:
  • Critical illness myopathy
  • Critical illness polyneuropathy
• Hard to distinguish types --> and usually not helpful --> both described as "ICU-Acquired Weakness"
• Management:
  • Complicates ventilator weaning, prolongs ICU stay.
  • No specific treatment options
  • Limit avoidable risk factors
  • Weakness may persist for years and indefinitely.

Post-ICU neuropsychiatric impairment

• Common (75%) - may persist for months, years, or indefinitely after critical illness.
  • 75% experience after hospitalization, and half still have impairment at 1-2 years post-discharge.
  • Considered "acquired dementia"
• High risk of depression, anxiety, loss of executive function.
• Risk Factors: (Risk factors are currently being studied!)
  • Age
  • Duration of mechanical ventilation
  • Poor glucose control (hyperglycemia)
  • hypoxemia

Nutrition in ICU

• Historically ICU patients were not given nutrition for many days after ICU admission.
• Many criticall illnesses --> high energy requirements!
• Poor nutrition contributes to:
  • Poor wound healing
  • Immunosuppression
  • Fluid / Electrolyte balance issues
• Evidence suggests critically ill pts may not need nutritional support early in illness.
  • In fact, overfeeding with high-fat formulations --> increases CO2 and hard to ventilate.
• When decide to feed: Enteral feeding is preferred
  • Post-pyloric feeding tubes did not show better outcomes than gastric feeding.
    • No difference in: reflux, aspiration, pneumonia, length of ICU stay, mortality.
    • Delayed gastric agents is common (use metoclopramide or erythromycin)
• Harris-Benedict equation used in ICU to estimate nutrition requirements. (often not useful)
• Can check pre-albumin for protein/caloric malnutrition (<50mg/L is severe)

Care Algorithms for Best Practice

• Evidence-based care algorithms help in ICU
• Standard algorithms are needed for:
  • DVT prophylaxis
  • Bladder catheter management
  • Glucose control
  • Transfusion requirements
  • Pressure ulcers
  • Delirium reduction
  • Goals of care assessments/discussions
• "Care bundles" and checklists are examples of process measures:  (best practice, improve care). Examples:

  • Examples:

    Bundle	Key Components
    Ventilator	Elevate head of the bed, daily “sedation vacation", assessment of readiness to extubate, PUD prophylaxis, DVT prophylaxis, daily oral care w chlorhexidine
    Central line	Hand hygiene, barrier precautions, chlorhexidine skin antisepsis, site selection, daily review if needed
    Sedation	Protocol-directed sedation, use sedation scales, bolus doses of benzos instead of continuous infusion, use of sedatives with a short duration of action, daily interruption of sedation
    Delirium	Daily check for delirium, minimize risk factors for delirium, sedation protocols
    Urinary	Daily check for catheter removal, utilize securement device, use reminder system

Structure of ICU

• Closed vs. Open unit
• Closed --> managed by a dedicated intesivist
  • Reduces mortality (best effect on pts admitted for longer than 48hrs)
  • Less resource utilization
• Most ICUs are "open" due to lack of specialized physicians.

Rapid Response Teams

• Bring critical care expertise to bedside outside of ICU.
• Identify, treat, and transfer unstable patients to ICU.
• Reduction in hospital mortality not yet shown.
• Reduction in cardiac and respiratory arrests outside of ICU has shown to be reduced.