Introduction to Acute Care/Critical Care Flashcards
Pharmacokinetic alterations in critical illness - absorption
oral absoprtion –> impaired/unpredictable in critically ill pts: alterations in gastric emptying, gastric motility; interactions with enteral feeding/GI tubes (i.e. fluoroquinolones, phenytoin); GI injury/disease
IV route used for treatment of serious conditions
How do we assess absorption?
have limited ways; take leap of faith, it pt is tolerating EN, can tolerate the meds
Pharmacokinetic alterations in critical illness - distribution
alterations vary between different critically ill pt populations: relates in part to fluid/hydration status; hydrophilic drugs (i.e. aminoglycosides) –> highed Vd in critically ill surgical/trauma pts than in medical pts
Pharmacokinetic alterations in critical illness - distribution: alteration in plasma protein binding
alterations in plasma protein binding: decrease in albumin (due to underlying stress)–> decrease protein binding of many drugs; increase acute phase proteins (i.e. alpha-1 acid glycoprotein) –> increase protein binding of drugs that bind alpha1-acid glycoprotein
Pharmacokinetic alterations in critical illness - metabolism
hepatic metabolism: hepatic blood flow, enzyme expression and activity, protein binding
in general –> hepatic enzyme expression nad activity may be decreased in some critically ill pts (many pts have some degress of impairment in hepatic metabolism)
Pharmacokinetic alterations in critical illness - renal elimination
renal dysfunction is a common complication during critical illness: shock, sepsis-related organ failure, nephrotoxic drugs
HD or continuous renal replacement therapy is common in ICU
some disease states may be associated with increased renal elimination: burns, traumas; cardiac output greater, renally excretes mores, need to give higher dose
How do we detect changes in renal function?
more immediate - use urine output on hourly basis, looking at the ins/outs
Disease states unique to critical care - sepsis
life threatening organ dysfunction caused by dysregulated immune response to infection: immune dysregulation; coagulation and thrombosis leading to endothelial injury
high mortality rates
can occur in response to any pathogen (bacterial most common) and any site of infection (common: lungs, bloodstream, urinary tract)
Sepsis drug therapy
no specific drug therapy; early detection and supportive therapy is critical
antimicrobial therapy (broad spectrum IV antibiotics) and source control (is there a specific source we need to remove)
Disease states unique to critical care - septic shock
sepsis associated with cardiovascular collapse/hypotension: hypotension related to decreased vascular tone (vascular cannot maintain adequate tone to maintain adequate BP
Septic shock treatment
fluids (crystalloids, colloids) - not sufficient to reverse the shock on their own, but still need to be fluid resusitated
vasopressors (increase vascular tone through alpha1, potentially cardiac output): target MAP >/= 65 mmHg, norepinephrine preferred, can also use phenylephrine, epinephrine, dopamine; vasopressin (add-on); dobutamine (inotrope)
corticosteroids (IV hydrocortisone) if refractory
Disease states unique to critical care - respiratory failure
respiratory failure/mechanical ventilation is a common reason for ICU admission
numerous causes/etiologies: airway compromise, hypoventilation, hypoxic failure (poor air exchange), inability to protect airway, others
significant proportion of ICU rounds devoted to ventilator management
Acute respiratory distress syndrome (ARDS)
life threatening respiratory failure characterized by acute, diffuse inflammatory lung injury (turns fibrotic over time)
risks inlude: pneumonia, sepsis, trauma, aspiration
often requires mechanical ventilation with sedation, potentially neuromuscular blockade
corticosteroids may decrease mortality in severe ARDS
General supportive care - FAST HUGS BID
F: feeding, fluids
A: analgesia
S: sedation
T: thromboprophylaxis
H: HOB elevation
U: ulver (stress ulcer) prophylaxis
G: glycemic control
S: spontaneous awakening trial, spontaneous breathing trial
B: bowel regimen
I: indwelling catheters
D: de-escalation of antibiotics, delerium assessment
General supportive care - feeding
many ICU pts unable to take adequate oral intake
may have specialized nutritional requirements: liver, renal failure, increased caloric, nutrient needs (trauma/surgery/burn)
enteral nutrition and parenteral nutrition common: enteral preferred, can be complicated by decreased GI motility, underlying disease states
General supportive care - fluids
consider maintenance and resuscitation requirements
crystalloids, colloids, blood products, others
goal is adequate resuscitation and meeting maintenance requirements without causing fluid overload
carefully monitor ins and outs
General supportive care - thromboprophylaxis
most critically ill pts have risk factors for venous thromboembolism (VTE): immobility, trauma, surgery, use of vascular catheters, sepsis, hypercoagulable states, cancer, obesity, prior history of VTE
can be complicated by underlying bleeding risks, active bleeding, need for invasive procedures, neuraxial anethesia
majority of ICU pts should receive pharmacological VTE prophylaxis unless sufficiently mobile and very low risk OR contraindications to pharmacological prophylaxis
General supportive care - thromboprophylaxis treatment
low molecular weight hepratin (LMWH) generally preferred over unfractionated heparin (UFH) - offers efficacy benefits especially in surgery/trauma pts
UFH; LMWH: enoxaparin, dalteparin; others: fondaparinux, bivalirudin, argatroban, warfarin, dabigatran, rivaroxaban, apixaban
mechanical prophylaxis in pts with contraindications to pharmacolog prophylaxis
UFH dosing and monitoring
5000 U SC q8h or q12h (possibly 7500 U SC q12h)
monitoring: s/s of bleeding, CBC (platelets for HIT); no reason to monitor APTT if on prophylactic dose
no adjustment for renal dysfunction
Enoxaparin dosing and monitoring
30 mg SC q12h, 40 mg SC q24h (may dose based on anti-Xa activity in selected pts)
monitoring: s/s of bleeding, CBC (platelets for HIT)
CrCl < 30 mL/min: 30 mg SC q24h
General supportive care - head of bed elevation
to reduce aspiration risk
General supportive care - stress ulcer prophylaxis
stress related mucosal damage (SRMD, stress ulcers): superficial lesions commonly involving the mucosal layer of the stomach following major stressful events (physiologic stress); may or may not be clinically important
clinically important bleeding likely uncommon but associated with high morbidity and mortality
Stress ulcer risk factors
shock, coagulopathy, chronic liver disease
mechanical ventilation/respiratory failure
neurotrauma, burn injury, extracorporeal life support
drugs: antiplatelet agents, anticoagulants, NSAIDs
Stress ulcer prophylaxis
prohylaxis: histamine-2 receptor antagonists (H2RAs), proton pumo inhibitors (PPIs), enteral feeding (should not be used as sole prophylaxis in high-risk pts, only somewhat protective, has local effect on mucosal lining)
D/C SUP when risk factors no longer present
PPI vs H2RA
controversial
guidelines doe not recommend one vs the other
some suggestion that PPIs may be more effective in preventing clinically important bleeding, but effects on mortality unclear
H2RAs
enteral or parenteral
ADRs: potential thrombocytopenia (rare)
famotidine, ranitidine
PPIs
enteral or parenteral: some formulation issues with feeding tube administration; sometimes can clog feeding tube
potential for increased risk clostridium difficile colitis, nosocomial pneumonia
effect on mortality controversial
omeprazole, lansoprazole, pantoprazole, esomeprazole, rabeprazole
SUP summary
prophylaxis generally considered to be warranted in critically ill pts considered to be at high risk: mechanical ventilation, coagulopathy, chronic liver disease, shock
choice of PPI vs H2RA remains controversial: PPIs likely associated with lower incidence of clinically important bleeding; PPIs may be more likely to be associated with infectious complications (controversial), mortality effects unclear
D/C prophylaxis when risk factors no longer present
General supportive care - glycemic control
hyperglycemia is associated with increased ICU mortality
multifactorial causes (not limited to pts with underlying diabetes): underlying stress, TPN
specific target controversial (balance b/w risk of hypoglycemia and hyperglycemia
target BG 144-180 mg/dL: initiate insulin if BG > 180 mg/dL - sliding scale, continuous infusion, electronic glucose management systems, avoid long-acting insulin formulations in unstable pts
General supportive care - spontaneous awakening trial, spontaneous breathing trial
helps prevent oversedation and promotes weaning from mechanical ventilation
General supportive care - bowel regimen
hypomotility is common in critical illness: particularly in pts on high dose/prolonged opioids
constipation: stool softeners (senna), laxatives (polyethylene glycol, docusate sodium, lactulose
gastroparesis: promotility agents (metoclopramide, erythromycin)
D/C if pt is having diarrhea/frequent stools
General supportive care - indwelling catheters
assess need, replace regularly, remove if infected
General supportive care - de-escalation of antibiotics
often start with broad spectrum coverage, refine and de-escalate based on culture results and clinical response to prevent resistance
