Pharmacologic Considerations for Ventilator Management & Weaning Mini Lecture RET 2264C Dr. J.B. Elsberry Prof. J.M. Newberry Special Thanks to: Sue Pilbeam, MS, RRT

Why do we need to Medicate Patients in the ICU?

Keeping the Patient Comfortable on the Ventilator  Patient Comfort and Pain Control  Managing Anxiety  Pt Flow Demands and Ventilator Synchrony  Deep Sedation and Anesthesia  Muscular Paralysis

Analgesia (Pain Control) Pain Control: Opiates and Synthetics  Morphine Sulfate (MS)  Meperidine HCL (Demerol)-- 1/20 MS  Dilaudid -- 4 x MS  Fentanyl (Sublimaze) x MS

Levels of Sedation  Minimal Sedation  Patients can respond to verbal commands although cognitive function may be impaired. Ventilatory and cardiovascular functions are unaffected.  Moderate Sedation (conscious sedation)  The patient can respond to verbal commands but may require tactile stimulation. Spontaneous ventilation and cardiovascular function are maintained.

Levels of Sedation II  Deep Sedation  Patient is not easily aroused but can respond to painful stimulation. Spontaneous ventilation and maintenance of patent airway may be inadequate. Cardiovascular function is maintained.  Anesthesia  This level involves general anesthesia, spinal, or major regional anesthesia; local anesthesia is not included. Patient cannot be aroused, even by painful stimulation. Ventilatory assistance is typically required (i.e., artificial airway and positive pressure ventilation). Cardiovascular function may be impaired. Adapted from Joint Commission on Accreditation of Health Care Organizations, Standards and intents of sedation and anesthesia. Comprehensive accreditation manual for hospitals: the official handbook. Chicago: The joint Commission, January 1, 2001 Update.

The Ramsay Scale ScoreDescription 1.Patient is awake but anxious, agitated, and restless 2.Patient is awake, cooperative, oriented, and tranquil 3.Patient is semi-asleep but responds to verbal commands 4.Patient is asleep; brisk response to a light glabellar tap or loud auditory stimulus 5.Patient is asleep; sluggish response to a light glabellar tap or loud auditory stimulus 6.Patient is asleep; no response to a light glabellar tap or loud auditory stimulus

Sedation Agents & Onset of Action  Diazepam 2-5 min  Midozolam 2-5 min  Lorazepam 5-20 min  Propofol 1-2 min  Haloperidol 3-20 min Adapted from: Jacobi et al.: Clinical Practice Guidelines for Sustained Use of Sedatives and Analgesics in the Critically Ill Adult. Am J Health-Syst Pharm 59: , 2002

Neuromuscular Blockers NMBA’s  Depolarizing Agents  Short Term Paralysis Succinylcholine (diACh). Succinylcholine chloride (Anectine)

Neuromuscular Blockers for M.V. Non-Depolarizing Agents Long Term Paralysis  Pancuronium. Pancuronium (Pavulon)  Vecuronium. Vecuronium bromide (Norcuron)  Atracurium/Cisatracurium. Atracurium bensylate (Tracrium)

Combination of Agents  Analgesia  Sedation  Analgesia + Sedation  Sedation + NMBA  Sedation + Analgesia +NMBA  NMBA is never given solo

Train of Four Monitoring  There are numerous techniques that are designed to test the depth of neuromuscular blockade using peripheral nerve stimulation; however, the TOF approach is considered to be the easiest and most reliable method for the ICU setting. 1 Four equal electrical charges are delivered every 0.5 s from the nerve stimulator device that is attached to leads overlying a superficial nerve, usually the ulnar or facial nerve, and the contraction of the innervated muscle (ie, the adductor pollicis or obicularis occuli muscle, respectively) is graded subjectively by palpation or observation 1

What Happens if the Pt. Extubates Themselves?

Success off the Vent…  “The best indicator of ventilator discontinuation potential is the clinical assessment of patients during the minutes spontaneous breathing trial (eg respiratory rate, BP, HR, comfort/anxiety, oxygenation, SpO2.” --Dr. N. MacIntyre (2001)

Weaning Terms Weaning Terms  Weaning is the process of withdrawing mechanical ventilatory support and transferring the work of breathing from the ventilator to the patient

Measure and estimation of WOB  WOB*< 0.8 Joules/L  Oxygen cost of breathing*. VO2< 15 % of total VO2< 15 % of total  Dynamic Compliance> 25 mL/cm H2O  V D /V T < 0.6

Physiological parameters for weaning and extubation of adults  Ventilatory Performance and Muscle Strength  VC> 15 mL/kg (IBW)  V E <10 to 15 L/min  V T > 4 mL/lb (IBW)  Respiratory rate (f)<35 breaths/min (adult)  Rapid, shallow breathing index (RSBI) (f/V T )<105 breaths/min/L (spontaneously breathing) (f/V T )<105 breaths/min/L (spontaneously breathing)  Ventilatory patternsynchronous and stable  PImax (NIF)( up to 20 sec measurement from RV)  < – 20 to 25 cm H 2 O

Measurement of adequacy of oxygenation  PaO2 >60 mm Hg on FIO 2 60 mm Hg on FIO 2 <0.4  PEEP < 5 – 8 cm H2O  PaO2/FIO2 (P/F Ratio) > 250 mm Hg (may consider weaning at mm Hg)

Additional Oxygenation Measures  PaO2/PAO2 >0.47  P(A–a)O2 <350 mm Hg on FIO2 = 1.0  Percent shunt Q S /Q T < 20% to 30%

Wean Screen & SBT  Assess: – RSBI –VC –NIF (MIP) –LOC  SBT  Progressive Weaning  Algorithmic Protocol (Closed Loop Methods)

Remember NPPV may be an Intermediate Step prior to successful weaning…

How do you measure “ Success ”  Weaning success is defined as effective spontaneous breathing without any mechanical support for 24 hours or more Next, let’s look at what the Ventilator Disconnection Weaning studies show…