Anesthesia Issues

1
Anesthesia Issues

• Propofol for pediatric procedural sedation
• reducing the pain on propofol
  injection
• laryngospasm
• February 7, 2002
• Sarah McPherson

2
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.2000342(12)938-945

3
What is the current status?

• Most peds sedation is with Ketamine or Midazolam
  a narcotic
• NEJM.2000342(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.199934(4)483-91

4
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.199990(6)1617-23

5
More concerns

• Hypoxia
• hypotension
• apnea
• laryngospasm
• overshooting depth of anesthesia

6
Propofol infusion syndrome

• Reported in 18 children
• children admitted to ICU
• sedated with high doses of propofol for gt 48 hr
• progressive myocardial failure and death
• Paed Anasth.19988(6)491-9

7
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.199826(12)1959-60

8
Propofol in the OR

• Safety documented in surgical, opthamologic,
  urologic and dental procedures
• Gastro Endo.200255(1)
• routinely used at ACH for induction of anesthesia

9
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.2000106(4)742-7

10
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.200123(5)290-3

11
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.1999171-3

12
Use for diagnostic imaging

• 2 English studies
• N 82, 34 with wt lt 10 kg, 48 gt 10 kg
• all received supplemental oxygen
• 10 transient hypotension, 1 hypoxia
• Acta Anaesth sand.199640(5)561-5
• N 30 (1-10 yrs)
• all received supplemental oxygen
• 7 hypoxia secondary to apnea (resolved with
  gental stimulation)
• no hypotension
• Anesth.199379(5)953-8

13
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.200255(1)

14
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.19996(10)989-97

15
Propofol for kids

• 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

16
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. 4212 pp.1108-12
• Br J Anaest. 1994. 72 pp.342-44

17
What has been looked at?

• Temperature pH
• injection site opioids
• local anaesthetics speed of injection
• sedatives NSAIDS
• What really works???

18
What do the studies show?

• Temperature
• warming to 37 oC or cooling to 4oC 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.199778502-506

19
What do the studies show?

• Injection site
• dorsum of hand 50 experience pain
• antecubital fossa 0 experienced pain
• Anaesthesia.198843(6)492-4
• Speed of injection
• pain with bolus 50 vs 73 when given over 75 sec
• Anaesthesia.198843(6)492-4

20
What do the studies show?

• NSAIDs
• 10 mg ketorolac venous occlusion X 2 min
  decreased pain
• ketorolac causes injection pain
• Anaesth.200055284-287
• 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

21
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.199269316-317
• Acta Anasthes Scan.199943(1)24-7
• Thiopental
• conflicting evidence
• gt100mg decrease incidence of pain from 50 to 12
• Anaesthesia.199449817-818
• 50mg no difference from controls
• Can J Anesth.199542(12)1108-12

22
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.199735(4)217-21
• Mid East J Anesthes.199613(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.199236564-68 Br J
  Anaesthes. 199472342-44
• Anesth Analg.199682469-71

23
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.198543(6)91-2
• Anaethes.198843(6)492-4
• Dose?
• 3 studies have looked at doses gt 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
  (N50)
• Anaesthes.199247604-6 Anesthes.199583(3A)A38
  5 Anaesthes.19904570

24
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.200090(4)936-9

25
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

26
Laryngospasm
27
Laryngospasm

• a prolonged occlusion of the glottis caused by
  contraction of the intrinsic laryngeal muscles
• Am J Otol.199516(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.198428567-575

28
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.198428567-575
• 3-6 prospective data in kids
• J Clin Anesthes.19924(3)200-3

29
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.198428567-575
• in children, 9 of 293 cardiac arrest (3)
  secondary to laryngospasm
• Anesthesiology.200093(1)6-14

30
Risk Factors

• Stimulation gt depth of anesthesia
• maintaining ETT with light anesthesia
• Stimulation
• blood, mucous, vomitus
• laryngeal or trigeminal nerve stimulation

31
Risk Factors

• URTI
• 2 fold higher risk of laryngospasm in kids with
  active or recent URI undergoing GA
• Anesthesiology.199685(3).475-480
• Second hand tobacco smoke
• 9.5 vs 0.9 risk of laryngospasm with GA
• Anesthes Analg.199682724-7

32
Risk Factors

• Type of airway adjunct
• facemask-oral airway lt LMA ETT
• Can J Anesth.200047(4)315-18
• Anesth Analg.199886706-11
• Anesthisiology.199888(4)970-77
• case reports with use of jet ventilation intraop
• Drugs
• case reports of midazolam or fentanyl causing
  laryngospasm
• Ann Emerg Med.199832(2)263-5
• Anaesth.199550(9)375
• Crit Care Med.200028(3)836-9

33
Treatment of Laryngospasm

• Stop the stimulus if possible
• Jaw thrust
• counteracts the descent of the hyoid and can
  reverse the ball valve effect

34
Treatment

• CPAP
• apply 20-30 cm H2O
• apply constant pressure
• avoid gastric insufflation
• apply styloid pressure

35
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.199348(3)229-30

36
Treatment what if I dont have iv access?

• IM sux
• sites deltoid, quad femoris, intralingular
• dose 3mg/kg

37
Treatment

• Time to apnea after Sux
• IM deltoid / quads 210 sec
• IM, tongue 75 sec
• IV 35 sec
• Anesth Analg.196847605-15

38
Treatment

• Time to max twitch depression
• IM quads 295 sec
• IM tongue 265 sec
• IM tongue digital massage 133 sec
• Anesth Prog.199037(6) 296-300

39
Treatment

• Benefits of the submental approach
• very vascular region
• fastest onset of action if iv not available
• can inject while masking

40
Treatment - other options

• Nitroglycerin
• N 2
• dose 4 microg/kg iv
• relief within 1 minute
• Acta Anaeths Scan.199943(10)1081-3
• intranasal lido epi
• N 2
• 5 cc 1 lido with epi intranasal
• relief within 10 seconds
• Ann Emerg Med.198514(3)275-6

41
Prevention

• Literature available only looks at post op
  prevention
• fentanyl prior to laryngeal stimulation does not
  prevent laryngospasm but does blunt airway
  reflexes
• Anesthesiology.199888(6)1459-66
• topical lidocaine (4mg/kg) prior to extubation
  decrease laryngospasm post TA
• Arch Otol.19911171123-8
• reduce modifiable risk factors

42
Laryngospasm take home points

• Simple maneuvers often work
• practice good mask technique
• know when to give sux
• if you dont have an iv submental sux with
  digital massage is a good option