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Anesthesia Issues. Propofol for pediatric procedural sedation reducing the pain on propofol injection laryngospasm February 7, 2002 Sarah McPherson. Pediatric procedural sedation.
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Anesthesia Issues Propofol for pediatric procedural sedation reducing the pain on propofol injection laryngospasm February 7, 2002 Sarah McPherson
Pediatric procedural sedation “ The goal of procedural sedation is the safe and effective control of pain, anxiety, and motion so as to allow a necessary procedure to be performed and to provide an appropriate degree of memory loss or decreased awareness.” NEJM.2000;342(12):938-945
What is the current status? • Most peds sedation is with Ketamine or Midazolam + a narcotic NEJM.2000;342(12):938-45 • adverse effects including: oxygen desaturation, apnea, stridor, laryngospasm, bronchospasm, cardiovascular instability, emesis, aspiration, emergence reactions, and paradoxical reactions occur in approximately 2.3% of cases Ann Emerg Med.1999;34(4):483-91
Why the concerns about propofol? • Concerns of upper airway obstruction • 10 children aged 2-10 • deep sedation with propofol but none were intubated • MRI to visualize glottic structures during sedation • preserve upper airway at all measured sites Anesth.1999;90(6):1617-23
More concerns • Hypoxia • hypotension • apnea • laryngospasm • overshooting depth of anesthesia
Propofol infusion syndrome • Reported in 18 children • children admitted to ICU • sedated with high doses of propofol for > 48 hr • progressive myocardial failure and death Paed Anasth.1998;8(6):491-9
Lactic acidemia and bradyarrhythmias • Refractory acidemia, bradycardia, hypotension, lipemia and oliguria • reported in 11 children after propofol infusion in the ICU • direct link to propofol not proven • no case reports with one time use Crit Care Med.1998;26(12):1959-60
Propofol in the OR • Safety documented in surgical, opthamologic, urologic and dental procedures Gastro Endo.2002;55(1) • routinely used at ACH for induction of anesthesia
What about procedural sedation? • In the ICU • prospective study N = 50 • sedation with intermittent boluses of propofol • preprocedure fasting • 68% systolic hypotension, 30% requiring iv fluid • 4% hypoxia • 12% partial upper airway obstruction • 2% apnea • no children require oral airways • start to recovery time = 23 min Pediatrics.2000;106(4):742-7
In the ICU • Retrospective, N = 52 children, 335 procedures • oncology patients • propofol, propofol + fentanyl, propofol + midaz • 6 episodes of hypoxia • 1 episode of laryngospasm J Ped Hem Onc.2001;23(5):290-3
In the ICU • Retrospective, N = 64 • pre procedure fasting • analgesia and sedation with either ketamine + midaz iv, Propofol and fentanyl iv, ketamine + midaz po • length of anesthesia time 17 min (range 10-50 min)in propofol group, 37 min (range 10 - 150min) • no respiratory depression, hypotension, or emesis in fentanyl/propofol group Am J Emerg Med.1999;17:1-3
Use for diagnostic imaging • 2 English studies • N = 82, 34 with wt < 10 kg, 48 > 10 kg • all received supplemental oxygen • 10% transient hypotension, 1% hypoxia Acta Anaesth sand.1996;40(5):561-5 • N = 30 (1-10 yrs) • all received supplemental oxygen • 7% hypoxia secondary to apnea (resolved with gental stimulation) • no hypotension Anesth.1993;79(5):953-8
Use in endoscopy • N = 50 • prospective randomized, propofol sedation vs inhalational GA • pre procedure fasting • 36% hypotension, no treatment required • 24% hypoxia, corrected with nasal prongs • 20% reversible apnea Gastro Endo.2002;55(1)
Use in the ED • N = 91 • prospective randomized, propofol vs midazolam • isolated extremity injuries, all received morphine • recovery times 14.9 +/- 11.1 in propofol 76.4 +/-47.5 min in Midazolam group • mild transient hypoxia 10% (similar in both groups) Acad Emerg Med.1999;6(10):989-97
Pros rapid recovery titrateable no emergence reaction Cons line between “conscious sedation” and borderline GA incidence of apnea and hypoxia likely higher than with ketamine small amounts of supporting data for use in ED Propofol for kids
Ouch! It hurts! • Injection pain reported in 40-90% of all cases • up to 50% of patients experience severe pain • recollection of pain is 50-80% post procedure • recollection of pain severity post procedure reflects pain on injection Can J Anesth. 1995. 42:12 pp.1108-12 Br J Anaest. 1994. 72 pp.342-44
What has been looked at? Temperature pH injection site opioids local anaesthetics speed of injection sedatives NSAID’S What really works???
What do the studies show? • Temperature • warming to 37 oC or cooling to4oC makes no difference compared to room temperature Anaesthesia. 1998.53,pp79-88 Paed Anasth. 2000.10(2):129-32 Anesthesiology. 1998.89(4):1041 Anesthesiology. 1999.91(2):591 • pH • when decreased from 7.97 to 6.32 (with addition of lidocaine or HCl) found decrease in pain Br J Anaesth.1997;78:502-506
What do the studies show? • Injection site • dorsum of hand 50% experience pain • antecubital fossa 0% experienced pain Anaesthesia.1988;43(6):492-4 • Speed of injection • pain with bolus 50% vs 73% when given over 75 sec Anaesthesia.1988;43(6):492-4
What do the studies show? • NSAID’s • 10 mg ketorolac + venous occlusion X 2 min decreased pain • ketorolac causes injection pain Anaesth.2000;55:284-287 • topical lidocaine + ionophoresis • 50% placebo group described severe pain vs 75% with no pain and 25% with mild pain in lido group Br J Anaest.1999.82(3):432-4
What do the studies show? • Metoclopramide • reduction from 50% to 24% with pretreatment with 5-10 mg iv, similar to effect with lido Br J Anaest.1992;69:316-317 Acta Anasthes Scan.1999;43(1):24-7 • Thiopental • conflicting evidence • >100mg decrease incidence of pain from 50% to 12% Anaesthesia.1994;49:817-818 • 50mg no difference from controls Can J Anesth.1995;42(12):1108-12
What do the studies show? • Fentanyl • studied with 150ug injected with venous occlusion for 1 min. prior to propofol injection • conflicting evidence Acta Anaesthes Sinica.1997;35(4):217-21 Mid East J Anesthes.1996;13(6):613-9 • Alfentanil • 1 mg injected prior to propofol decreases pain from 67-84% to 24-36% (similar to lido) 15ug/kg in kids similar to 0.5 mg/kg of lido Acta Anaesthes Scand.1992;36:564-68 Br J Anaesthes. 1994;72:342-44 Anesth Analg.1996;82:469-71
What the studies show • Lidocaine • all studies show a reduction in pain scores with lido • premixed within 30 min with propofol is better than pre-injection with lido Anaesthes.1985;43(6):91-2 Anaethes.1988;43(6):492-4 Dose? • 3 studies have looked at doses > 20mg/induction • doses of 0.4-0.6mg/kg for adults or 0.2 mg/kg for kids appear to be more effective • case series using 1mg/kg reduced pain to 0% (N=50) Anaesthes.1992;47:604-6 Anesthes.1995;83(3A):A385 Anaesthes.1990;45:70
lidocaine • Most effective analgesia with a bier block • 0.5 mg/kg lidocaine • rubber tourniquet to forearm for 30-120 sec • absolute risk reduction of pain = 60% • NNT = 1.6 Anesth Analg.2000;90(4):936-9
The bottom line • 0.5 mg/kg lidocaine injected with a tourniquet is the best method to prevent pain • Premixed lidocaine with propofol works. I would use 0.5mg/kg • alfentanil 1mg prior to injection may further reduce pain • larger veins for infusion cause less pain
Laryngospasm • “a prolonged occlusion of the glottis caused by contraction of the intrinsic laryngeal muscles” Am J Otol.1995;16(1):49-52 • in general it is considered present when inflation of the lungs is impossible secondary to laryngeal muscle contraction and other causes are excluded (ie occluding tongue, bronchospasm) Acta Anaesthes Scan.1984;28:567-575
What is the incidence • Unable to find any references citing frequency in the ED patient population • literature post GA: • 0.87% in adults • 1.23% age 0-9 yr • 2.28% age 1-3 month Acta Anaesthes Scand.1984;28:567-575 • 3-6% prospective data in kids J Clin Anesthes.1992;4(3):200-3
Potential Complications of laryngospasm • Bronchospasm 4.3% • Hypoxia 3.5% • Vomiting 8.1% • Aspiration 1.2% • Arrhythmia 1% • Cardiac arrest 0.5% Acta Anaesthes Scan.1984;28:567-575 • in children, 9 of 293 cardiac arrest (3%) secondary to laryngospasm Anesthesiology.2000;93(1):6-14
Risk Factors • Stimulation > depth of anesthesia • maintaining ETT with light anesthesia • Stimulation • blood, mucous, vomitus • laryngeal or trigeminal nerve stimulation
Risk Factors • URTI • 2 fold higher risk of laryngospasm in kids with active or recent URI undergoing GA Anesthesiology.1996;85(3).475-480 • Second hand tobacco smoke • 9.5% vs 0.9% risk of laryngospasm with GA Anesthes Analg.1996;82:724-7
Risk Factors • Type of airway adjunct • facemask-oral airway < LMA = ETT Can J Anesth.2000;47(4):315-18 Anesth Analg.1998;86:706-11 Anesthisiology.1998;88(4):970-77 • case reports with use of jet ventilation intraop • Drugs • case reports of midazolam or fentanyl causing laryngospasm Ann Emerg Med.1998;32(2):263-5 Anaesth.1995;50(9):375 Crit Care Med.2000;28(3):836-9
Treatment of Laryngospasm • Stop the stimulus if possible • Jaw thrust • counteracts the descent of the hyoid and can reverse the ball valve effect
Treatment • CPAP • apply 20-30 cm H2O • apply constant pressure • avoid gastric insufflation • apply styloid pressure
Treatment • Succinylcholine • timing depends on the clinical situation: • can I break laryngospasm relatively quickly with CPAP? • What is the clinical status of the patient? • Do I have time to wait for succinylcholine to work? • Doses as low as 0.1mg/kg iv have been shown to effectively treat laryngospasm (N = 3) Anaesth.1993;48(3):229-30
Treatment: what if I don’t have iv access? • IM sux: • sites: deltoid, quad femoris, intralingular • dose: 3mg/kg
Treatment Time to apnea after Sux: • IM deltoid / quads 210 sec • IM, tongue 75 sec • IV 35 sec Anesth Analg.1968;47:605-15
Treatment Time to max twitch depression: • IM quads 295 sec • IM tongue 265 sec • IM tongue + digital massage 133 sec Anesth Prog.1990;37(6): 296-300
Treatment • Benefits of the submental approach: • very vascular region • fastest onset of action if iv not available • can inject while masking
Treatment - other options • Nitroglycerin: • N = 2 • dose 4 microg/kg iv • relief within 1 minute Acta Anaeths Scan.1999;43(10):1081-3 • intranasal lido + epi: • N = 2 • 5 cc 1% lido with epi intranasal • relief within 10 seconds Ann Emerg Med.1985;14(3)275-6
Prevention • Literature available only looks at post op prevention • fentanyl prior to laryngeal stimulation does not prevent laryngospasm but does blunt airway reflexes Anesthesiology.1998;88(6):1459-66 • topical lidocaine (4mg/kg) prior to extubation decrease laryngospasm post T&A Arch Otol.1991;117:1123-8 • reduce modifiable risk factors
Laryngospasm: take home points • Simple maneuvers often work • practice good mask technique • know when to give sux • if you don’t have an iv: submental sux with digital massage is a good option