Introduction to Acute Care/Critical Care

Question 1

Pharmacokinetic alterations in critical illness - absorption

Answer 1

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

Question 2

How do we assess absorption?

Answer 2

have limited ways; take leap of faith, it pt is tolerating EN, can tolerate the meds

Question 3

Pharmacokinetic alterations in critical illness - distribution

Answer 3

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

Question 4

Pharmacokinetic alterations in critical illness - distribution: alteration in plasma protein binding

Answer 4

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

Question 5

Pharmacokinetic alterations in critical illness - metabolism

Answer 5

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)

Question 6

Pharmacokinetic alterations in critical illness - renal elimination

Answer 6

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

Question 7

How do we detect changes in renal function?

Answer 7

more immediate - use urine output on hourly basis, looking at the ins/outs

Question 8

Disease states unique to critical care - sepsis

Answer 8

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)

Question 9

Sepsis drug therapy

Answer 9

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)

Question 10

Disease states unique to critical care - septic shock

Answer 10

sepsis associated with cardiovascular collapse/hypotension: hypotension related to decreased vascular tone (vascular cannot maintain adequate tone to maintain adequate BP

Question 11

Septic shock treatment

Answer 11

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

Question 12

Disease states unique to critical care - respiratory failure

Answer 12

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

Question 13

Acute respiratory distress syndrome (ARDS)

Answer 13

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

Question 14

General supportive care - FAST HUGS BID

Answer 14

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

Question 15

General supportive care - feeding

Answer 15

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

Question 16

General supportive care - fluids

Answer 16

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

Question 17

General supportive care - thromboprophylaxis

Answer 17

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

Question 18

General supportive care - thromboprophylaxis treatment

Answer 18

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

Question 19

UFH dosing and monitoring

Answer 19

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

Question 20

Enoxaparin dosing and monitoring

Answer 20

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

Question 21

General supportive care - head of bed elevation

Answer 21

to reduce aspiration risk

Question 22

General supportive care - stress ulcer prophylaxis

Answer 22

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

Question 23

Stress ulcer risk factors

Answer 23

shock, coagulopathy, chronic liver disease
mechanical ventilation/respiratory failure
neurotrauma, burn injury, extracorporeal life support
drugs: antiplatelet agents, anticoagulants, NSAIDs

Question 24

Stress ulcer prophylaxis

Answer 24

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

Question 25

PPI vs H2RA

Answer 25

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

Question 26

H2RAs

Answer 26

enteral or parenteral
ADRs: potential thrombocytopenia (rare)
famotidine, ranitidine

Question 27

PPIs

Answer 27

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

Question 28

SUP summary

Answer 28

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

Question 29

General supportive care - glycemic control

Answer 29

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

Question 30

General supportive care - spontaneous awakening trial, spontaneous breathing trial

Answer 30

helps prevent oversedation and promotes weaning from mechanical ventilation

Question 31

General supportive care - bowel regimen

Answer 31

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

Question 32

General supportive care - indwelling catheters

Answer 32

assess need, replace regularly, remove if infected

Question 33

General supportive care - de-escalation of antibiotics

Answer 33

often start with broad spectrum coverage, refine and de-escalate based on culture results and clinical response to prevent resistance