General ICU Concepts

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    Common Emergencies

    Acute Inhalational Injury

     

    Anaphylaxis

     

    Hypertensive Emergencies

     

    Alcohol Toxicity

     

     

    Everyday ICU Concepts

    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). 

     

    Clogged Tube

     

    • Prevent by doing frequent flushes with water (30 mL q4hrs), and 10mL after medications are given.
    • If clogged, try the following (in incremental order)
      • Try to instill warm water (30% effective)
      • Try Viokase (pancreatic enzyme) dissolve 1 tablet of Viokase, and 1 tablet of sodium carbonate (324mg) in 5mL of water.--> inject mixture into feeding tube and clamp for 5 min.  --> then flush with warm water (75% effective)
      • Try inserting flexible wire or drum-cartridge catheter to clear obstruction

     

    Hyperthermic Emergencies

    • Defined as: rise in core body temperature >40°C or (>104°F), can be life-threatening
    • Present with altered mental status, seizures, muscle rigidity, rhabdomyolysis (kidney failure).
      • If severe: can get DIC and ARDS.
    • Three common causes:
    1. Heat Stroke
    2. Malignant Hyperthermia
    3. Neuroleptic Malignant Syndrome

    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;
      •  

     

     

    Hypothermic Emergencies

    • Defined as core temperaturey <35°C (<95F)
    • Commonly due to cold weather exposure or cold water exposure.
    • Risk factors:
      • Impaired thermoregulation (elderly, intoxicated).
      • Lengthy surgical procedures (age, comorbidities, anesthesia).
    • Causes cellular dysfunction and electrolyte abnormalities (esp hyperkalemia).
      • Severity Temp Effects
        Mild 32-35°C

        Shivering, mental status changes, polyuria, ataxia

        ECG: lots of artifact, looks like AFib/Flutter

        Moderate 28-32°C

        CV: Decreased heart rate, cardiac output, cardiac arrhythmias

        Neuro: severe mental status change + other neuro dysfunction

        - May no longer shiver

        Severe <28°C

        Neuro: Coma, areflexia

        Resp: Pulmonary Edema

        CV: hypotension, ventricular arrhythmias + arrest

        ECG: J-Osborne Waves characteristic (Do not mistake for acute MI)

    • Treatment:
      • If shivering, can rewarm passively if remove from cold, dry, covered.
      • If not shivering: actively rewarm
        • External Warming
        • Invasive: Gastric, Peritoneal, Pleural space lavage
          • (Only indicated for severely hypothermic pts, with severe CNS depression or cardiac dysfunction).
      • Rewarming may be complicated by burns, organ dysfunction (i.e. rhabdomyloysis, DIC, pulmonary edema).

    Supportive Care in Critically Ill Patient

    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.
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