PICU



PICU


Elizabeth C. Parsons

Peter P. Moschovis

Elliot Melendez



General ICU Care Prophylaxis in Critical Illness


Ventilator-Associated PNA

(Am J Infect Control 2006;34:84) See section on VAP



  • Prevention strategies: Hand washing, HOB >30°, oral chlorhexidine bid (↓ risk in surgical pts), minimize narcotics, avoid unnecessary stress ulcer ppx (does not seem to ↑VAP risk in PICU pts). Neuromusc blockers impair gastric emptying.


Stress Ulcer

(AACN Adv Crit Care 2007;18:158)



  • Pathophysiology: Stress → splanchnic hypoperfusion → gastric mucosal breakdown and impaired gastric motility, leading to prolonged gastric acid exposure



    • pH has significant, nonlinear correlation w/ stress ulcer occurrence and bleeding.


    • pH 7.0 protective, below w/ increased risk.


    • After bleed, 50% ↓ in clot stability when pH dec from 7.4 to 6.5. (Crit Care Med 2002;30:S351)


  • Generally during 3rd–7th ICU d; can cause signif bleed (up to 4× inc mortality)


  • Prophylaxis indicated for high risk: Sepsis, shock, operative procedure ≥3 hr, trauma/closed-head injury, status epilepticus, acute renal or hepatic failure, anticoagulation or coagulopathy, burns >35% BSA, concurrent steroids, enteral feeds (Crit Care Med 1992;20:1519)


  • Regimens:



    • Proton pump inhibitors: Preferred



      • Most potent (dose-depend, 99% achieve pH = 7), max effect not until 48 hr


      • Risks: CYP450 metabolism, poss assoc w/ C. diff infxn, acute interstitial nephritis


    • Histamine2-receptor antagonists



      • Quicker onset of action but less effective. Maximum achievable gastric pH 4.0–5.0. After 24–48 hr, pH stabilizes at 3.0–4.0.


  • Risk of thrombocytopenia: Use PPI if Plt <50,000; cimetidine inh cytochrome P450


DVT Prophylaxis

(Thrombosis Research 2006;118:3)



  • See Pulmonary Embolism in Pulmonary section for details on treatment.


  • Incidence of DVT same as for adults (likely a result of more frequent ppx in adults)


  • Major ICU risk factor is CVL placement (18%–26% assoc w/ VTE in ICU). Others include prolonged immobility/paralysis (spinal cord injury), malignancy, sepsis, surgery/trauma, long-term TPN (up to 66%).


  • Dx: US most often used, but has low sensitivity (30%–80%).



    • In ICU, a neg US does not rule out DVT. If high suspicion, treat until able to confirm w/ contrast CT or venogram (gold standard)


    • Hypercoag workup recommended for all patients (same incidence as in adults)


  • Prophy: No consensus due to lack of pediatric studies; extrapolation from adults difficult 2/2 dif in developmental hemostasis (varying levels/response of clotting cascade proteins) & pharmacokinetic/dynamic properties of anticoag agents in children



    • Methods: TEDs or pneumoboots, rarely LMWH


    • Pediatric evidence: No benefit of prophy in trauma pts <13 yo (J Trauma 2005;59:1345) or w/ warfarin in pedi-onc pts w/ CVL (Acta Paediatr 2006;95:1053)


    • Bottom Line: Consider prophylaxis for adult-sized patients w/ significant risk factors (long-term immobilization, CVL, malignancy)



Pain Control and Sedation



  • Pain and sedation scores should be followed for all pts receiving sedatives or analgesics


  • Commonly Used Analgesics and Sedatives








































Drug Onset/peak (IV) Duration (IV) Relative Potency (IV) Starting Dose (IV)
Morphine 20 min 3–5 hr 1 Infant/Child: 0.05 mg/kg/dose. usual 0.1–0.2 mg/kg/dose q2–4h prn (max 15 mg/dose)
Dilaudid 15 min 5 hr 7 Child: 0.015 mg/kg/dose q3–6h prn
Fentanyl Immediate 30–60 min 100 Infants: Intermittent: 3 mcg/kg/dose q2–4h prn. Continuous: 1–2 mcg/kg load → 0.5–1 mcg/kg/hr; titrate upward Children: Intermittent: 1–2 mcg/kg/dose; may repeat at 30–60-min intervals. Continuous: 1–2 mcg/kg load → 1 mcg/kg/hr; titrate upward (usual: 1–3 mcg/kg/hr)
Versed 1–5 min 2–6 hr N/A 0.05 mg/kg IV ×1, repeat q2–3 min (max 0.4–0.6 mg/kg IBW); if vented cont at 0.5–1 mcg/kg/min titrate to effect
Ativan 15–30 min 8–12 hr N/A 0.05 mg/kg IV (also IM) q4–8h, max 2 mg/dose
These are suggested doses & do not replace clinical judgment. Follow institutional guidelines where available.




























Equianalgesic Dosing
  Oral (mg) IV (mg)
Morphine 30 10
Fentanyl N/A 0.1
Dilaudid 7.5 1.5
Codeine 200 N/A
Hydrocodone 20 N/A


Respiratory Failure



  • Definition: Failure of oxygenation, ventilation, gas exchange or airway protection


  • Diagnostic eval: ABG (VBG can be used to r/o hypercapnia), CXR (r/o PNA, edema).



    • Consider CBC (anemia), CT (if suspect PE), ECHO, BNP (if suspect shunt or CHF)


  • Treatment: Treat underlying cause, NPO (to prevent aspiration)



    • Hypoxemia: Supplemental O2, consider CPAP or intubation


    • Hypercapnia: Consider BiPAP or intubation


  • Hypoxemia (↓ Pao2)






































Cause A-a gradient SvO2 Distinguishing Features Clinical Scenario
Hypoventilation Normal     Drug o/d (benzo’s)
O2 delivery/consumption imbalance High Low   ↑ demand (stress, infection) ↓ supply (hypoxia, ↓ CO, anemia)
  High High   ↓ demand (poor utilization – late shock)↑ supply (high Fio2)
True shunt High Low/normal Does not correct w/O2 R->L intracardiac shunt, AVM, alveolar collapse or filling
VQ mismatch High Low/normal Corrects w/O2 Airway (asthma), alveolar (PNA, CHF), vascular (PE)


A-a gradient: Alveolar-capillary gas exchange

PAO2 – PaO2 = (FiO2 × 713) – (PaCO2/0.8))
normal value on RA ∼ 2.5 + (0.21 × age (yrs))

PAO2 = partial pressure of O2 in alveolus

PaO2 = oxygenation in artery



  • Most useful in assessing progression of lung disease Pao2/Fio2 ratio (oxygenation index): Measure of severity

Normal >300; ALI: Pao2/Fio2 201–300; ARDS: Pao2/Fio2 ≤200



  • Hypercapnea (↑Pco2)



















Cause Pathophysiology Clinical Scenario
Central ↓ resp drive Metabolic alkalosis, CNS event/infection, sedation (med or toxin related)
Pulmonary Lung/Airway Musculoskeletal * Note: ↑WOB may not be apparent; blood gas helpful. PNA, asthma, BPD, CF Obesity, kyphosis/scoliosis, pleural effusion. Neuropathy, botulism, myopathy (muscular dystropy, hypophosphatemia)
Increased production Increased CO2 production from inc metabolic rate Fever, sepsis, excess carb load


Mechanical Ventilation

Basic Definitions: see Pulmonary Formulae (Appendix)


Noninvasive Methods



  • CPAP: Continuous PEEP. Useful for hypoxemia (atelectasis, edema, OSA, HMD)


  • BiPAP: Pt-triggered PIP + CPAP. Useful for hypoventilation (CF, NM disease)


Invasive Methods



  • Support (PS/VS): Spont breaths assisted to reach goal pressure (P) or volume (V)



    • No set rate, pt must initiate breaths. Pt determines I time. Less efficient if ETT leak.


  • Assist/Control (AC): Vent delivers minumum # supported breaths (synch to pt effort) with add’l pt-initiated breaths getting full assist to reach goal P or V w/controlled l time.



    • Downside: Uncomfortable, dyssynchrony and auto-PEEP (breath stacking)


  • SIMV: Vent delivers minimum # supported breaths (sync to pt effort) but add’I pt-initiated breaths get no assist. May add PS to assist spont breaths (SIMV + PS)



    • Downside: Inc resp effort (pt must overcome circuit resistance during spont breaths)


  • HFOV: Rapid oscillatory breaths given at set frequency (Hz); manipulate MAP and ΔP



    • Downside: Can easily hypervent. Vent Δ may take longer to equilibrate on blood gas.


    • Used when conventional ventilation fails.


    • Initial trials supporting HFOV over conventional vent strategies were done before ARDSNet low TV protocols, which appear to have same mortality. They are likely equal, but HFOV may be easier way to obtain same result. (Crit Care 2005;9:177)


Troubleshooting



  • Acute desaturation: Think DOPE



    • Dislodgement (ETT); Obstruction (mucus plug); Pneumothorax; Equipment failure


  • Oxygenation depends on Mean Airway Pressure (MAP)


  • Ventilation depends on minute ventilation and dead space











































Vent Type Parameter to Change Increase O2 Decrease CO2
Conventional RR No effect ↑
  Fio2 ↑ No effect
  PEEP ↑ ↓
  PIP ↑ ↑
  I-time (should not be 1st line) ↑ ↓
HFOV MAP ↑  
  DeltaP   ↑


Pediatric ECMO/ECLS


Definition



  • Extracorporeal life support for lung &/or cardiac fxn (see NICU section for details)























  Circuit Indication To ↑ O2 To ↓ CO2 Considerations
V-V Blood returns to RA/central vein Resp failure Inc Fio2 HCT >35; inc flow; inc CO Inc sweep Less efficient oxygenation (SaO2 80%–95%), watch for recirculation
V-A Blood returns to aortic arch Combined cardioresp failure     Carotid/IJ ligation, direct arterial emboli, renal nonpulsatile flow, inaccurate CVP, lower coronary artery O2 supply, high LV afterload, cardiac stun


Pediatric Indications

Tags:
Aug 18, 2016 | Posted by in PEDIATRICS | Comments Off on PICU

Full access? Get Clinical Tree
Get Clinical Tree app for offline access