Pediatric Respiratory Emergencies

1. Pediatric Respiratory Emergencies Moritz Haager Dr. David Johnson May 09, 2002

2. Case • 8 mo male w/ 2/7 Hx of URTI Sx and progressively labored breathing • Presents w/ tachypnea, indrawing, lethargy, ill looking child • 380 / 200 / 60 / 88-90% on RA • Dec’d AE and diffuse wheeze bilat., creamy d/c from eyes • ABG: 7.38 / 38 / 51 / 22/ -2 • WBC 14.6 • CXR: peri-bronchial cuffing in RLL

4. What’s your DDx for wheeze? • Bronchiolitis • Pneumonia • Asthma • Foreign body aspiration • CHF • CF • Pertussis • Anatomic abnormalities

5. What’s your approach to bronchiolitis? • ABC’s • Oxygen • ?Bronchodilators (which one?) • ?Steroids • ?Antibiotics • Supportive care • Monitor for complications

6. Bronchiolitis • Common contagious LRTI of infants + young children (0-24 mo) • Usually viral and self-limited illness • RSV (60-90%) • Para-influenza, adenovirus, rhinovirus, influenza • Affects terminal bronchioles  necrosis of ciliated cells  inflammation w/ cellular debris + mucous plugging  wheezing and inc’d WOB • Seasonal epidemics (winter months) • Usually no long-term sequelae but may pre-dispose to (or uncover) asthma

8. Are bronchodilators useful? • Controversial point in literature • Meta-analysis looking at 15 RCT’s (mostly salbutamol) concluded moderate short-term benefit from bronchodilator therapy, but no effect on admission rate or oximetry • Kellner et al. 1996. Arch Ped Adol Med. 150: 1166-72 • Cochrane systematic review of 394 kids in 8 trials showed 54% improved clinically vs.. 25% of placebo • Concluded modest short-term symptomatic benefit; need more studies to better elucidate utility • Kellner et al. 2002. Coch Data Sys Rev. (1)

9. Salbutamol or Epinephrine? • 4 RCT’s show epinephrine (racemic or L-epi) as appearing to be superior to salbutamol • All found significant symptomatic improvement, and two found dec’d admission rate or shortened hospital stay; no adverse effects noted • Only 2 were in ED setting • Reijonen et al. 1995. Arch. Ped. Adol. Med. 149: 686-92 • Menon et al. 1995. J. Ped. 126: 1004-007 • Sanchez et al. 1993. J. Ped. 122: 145-51 • Bertrand et al. 2001. Ped. Pulmonolgy. 31: 284-8 • Hartling and Klassen in process of preparing a Cochrane review • Epi appears superior based on current evidence

10. What about Atrovent? • Double-blind placebo-controlled RCT of 69 infants 6wks – 24 mo w/ acute bronchiolitis • Randomized to either salbutamol + ipratropium or salbutamol + placebo • No sig difference in admission rate, RR, WOB, wheezing, or O2 sats • No additional benefit when given in addition to salbutamol. • Schuh et al. 1992. Pediatrics. 90: 920-23

11. Is there a role for Steroids? • 3 RCT’s all fail to show benefit • Roosevelt et al. 1990. Lancet. 348: 292-95 • Van Woensel et al. 1997. Thorax. 52: 634-47 • Klassen et al. 1997. J. Ped. 130: 191-196. • 3 more recent studies support this and also fail to show any long-term benefit in reducing risk of post-bronchiolitis wheezing or asthma • Van Woensel et al. 2000. Ped. Pulmonology. 30: 92-6 • Wong et al. 2000. Euro. Resp. J. 15: 388-94 • Cade et al. 2000. Arch. Dis. Child. 82: 126-30 • Literature does not support use in bronchiolitis • Patel et al are preparing a Cochrane review

12. Does this Kid need Antibiotics? • Not routinely indicated, but • One study shows ~86% of kids w/ bronchiolitis have concomitant OM • 5-10% have M. pneumoniae or Chlamydia co-infection • Consider Tx in kids with: • OM and high fever • Atypical features • More ill than expected • CXR evidence of pneumonia (other than atelectasis) • This child received IV amoxicillin for ill appearance

13. Your student suggests Ribavirin • Synthetic nucleotide anologue w/ virostatic properties • Expensive, possibly teratogenic, can cause bronchospasm • Controversial, but mounting evidence it does not work: • At least 3 RCT’s fail to show benefit • Everard et al. 2001. Resp. Med. 95: 275-80 • Guerguerin et al. 1999. Am. J. Resp. Crit. Care Med. 160: 829-34 • Moler et al. 1996. J. Ped. 128: 422-28 • Cochrane review of 378 infants < 6mo in 10 trials suggests possible decrease in length of stay, but studies lack sufficient power. • Randolph and Wang. 2002. Coch Data Sys Rev. Issue 1 • Bottom line: not indicated in ED

14. Other Treatments for Bronchiolitis • Shuang huang lian • 1 RCT shows dec’d duration of Sx • Heliox • One RCT in PICU showing benefit • Surfactant • Case reports in PICU setting • ECMO • Case reports of benefit in premies or unstable pts refractory to conventional Tx • Prevention • RSVIG • Palivizumab

15. What complication can arise? • Hypoxemia / respiratory failure • Apnea (esp. in <6 mo) • Hypercarbia • Pneumonia (viral or bacterial) • Concomitant OM • Long-term: ? Asthma – some studies suggest inc’d risk esp. in kids w/ inc’d IgE Mortality < 1%, and usually occurs in children w/ underlying heart dz, lung dz, or prematurity.

16. Are there any predictors of M+M? • Predictors of severe disease: • GA < 34 wks • SpO2 < 95% • RR >70 • Age < 3 mo • Ill or toxic appearance • Atelectasis on CXR • Presence or absence of all 6 has PPV of 81% and NPV of 88% for severe course • Shaw et al. 1991. Am. J. Dis. Child. 145: 151-55

17. Who needs intubation? • 2-7 % of hospitalized infants end up requiring intubation for resp. failure • Indications for intubation: • Severe resp. distress • Apnea • Hypoxia or hypercapnea • Lethargy • Poor perfusion • Metabolic acidosis • Wright et al. 2002. Emerg Med Clin NA. 20: 93-113

18. Case • 3 yo female presents w/ 3/7 Hx of coryza, fever, and a “harsh” cough • Today started making noise with every breath and hoarse voice which is worse at night • O/E: 386 / 120 / 35 / 96% RA • Inspiratory stridor

21. What’s your DDx for stridor? • Epiglottitis • Bacterial tracheitis • Retro-pharyngeal abscess • Croup • Uvulitis • Foreign body obstruction • Hemangioma • Neoplasm

22. What’s your approach to Croup? • ABC’s • Oxygen • ?Humidification • ?Epinephrine • ?Steroids • ?Intubation

23. Croup • = Laryngotracheobronchitis, viral croup • Common URTI and cause of stridor in infants and children 6 mo – 6 yo • Viral infection  inflammation of subglottic area  stridor (can be biphasic in severe cases)  potentially hypoxia and death (rare) • Biphasic: peaks in fall and winter • Etiology: • Parainfluenza 1 + 3 (>65%) > RSV > Parainfluenza 2 > Influenza A > M. pneumoniae > Influenza B

24. Humidification: does it work? • Long-standing first-line Tx at home • Anecdotal evidence • studies to date fail to show objective benefit from mist therapy, one of which was an RCT of 16 pts receiving either RA or humidified air • Bourchier et al. 1984. Aust. Pediatr. J. 20:289-91 • Reports of Pseudomonas contamination and hyper-sensitivity reactions • We need a larger RCT to clear this up • Cochrane review by Moore and Little in progress

25. Epinephrine a- effects: dec’d bronchial secretions + edema b- effects: bronchodilation, tachycardia • Most studies on racemic epinephrine but at least one double-blind RCT suggests equivalence to L-epi • Waisman et al. 1992d. Pediatrics. 89: 302-06 • 0.5 ml 2.25% racemic epinephrine = 5 ml 1:1000 L-epinephrine • L-epi more available and less expensive

26. Does Epi work in Croup? • 5 prospective double-blind RCT’s of epinephrine in croup • 4 demonstrate decreased airway obstruction with effect lasting 2 hours • Kuusela et al. 1988. Acta Paed. Scand. 77: 99-104 • Taussig et al. 1978. Am J Dis Child 132: 484-87 • Westley et al. 1978. Am J Dis Child 132: 484 • Fogel et al. 1982. J. Ped. 101: 1028-31 • One failed to show any benefit but unsure of length of observation time • Gardner et al. 1973. Pediatrics 52: 52-55 • Epinephrine appears to offer symptomatic benefit

27. Does Epi help decrease admission? • 3 studies totaling 166 pts who got epi + steroids, observed for 2-3 hrs and then discharged w/ arranged f/u in 48 hrs • 47/50 required no further Tx in one study, while the other 2 were able to D/C 55% and 51% of pts w/ only 1 recurrence of resp. distress in pts who otherwise would have been admitted • Kelly et al. 1992. Am J Emerg 10: 181-83 • Ledwith et al. 1995. Ann Emerg Med 25: 331-37 • Prendergast et al. 1994. Am J Emerg Med. 12: 613-16

28. How much epi can we safely give? • Studies give 0.05 ml/kg or 0.25-0.5 ml a of 2.25% RE sol’n; don’t often quote frequency • Locally known to give 0.5 ml q2h O/N • Case report of MI in pediatric pt following multiple doses of RE via neb • Developed short run of VT, and mild transient CP • Abnormal ECG and elevated CK-MB • Structurally normal heart as per echo + angio but small infarct seen by nuclear stress scan • Butte et al. 1999. Pediatrics 104: e9 • Suggests we should be more cautious

29. Steroids • Postulated to work by anti-inflammatory effect to decrease edema, but exact mechanism uncertain • Onset of effect usually quoted as being ~6 hrs, but some have observed effect as early as 2 hrs

30. Are Steroids useful in Croup? • One meta-analysis comprising 1286 pts in 10 RCT’s and 2 RCT’s quoted as strong evidence demonstrating faster clinical improvement, dec’d likelihood of intubation, and shorter admissions. Also suggests better effect w/ higher doses. • Kairys et al. 1989. Pediatrics. 83: 683-93 • Super et al. 1989. J Ped. 115: 323-29 • Kuusela and Vesikari. 1988. Acta Paed Scand. 77: 99-104 • More recent meta-analysis of 24 RCT’s ( incl. 15 new studies) demonstrates symptomatic improvement, fewer interventions, and shorter hospital stays in steroid-treated children w/ NNT of 5-7, but did not show dec’d risk of intubation • Ausejo et al. 1999. BMJ. 319: 595-600 • Cochrane review concluded CS are effective in relieving the Sx of croup and decreasing need for co-interventions, and length of stay in hospital • Ausejo et al. 2002. Coch Data Sys Rev Issue1

31. What steroid, what route, what dose? • IM Dexamethasone was shown to be superior to budesonide in one RCT • Johnson et al. 1998. N Engl J med. 339: 498-503 • Dexamethasone can be given IM or PO; no head-to-head comparison studies • Dose more controversial: • Kairys et al: inc’d benefit w/ doses > 0.3 mg/kg • Another double-blind RCT of 120 children concluded a dose of 0.15 mg/kg just as effective • Geelhoed and Macdonald. 1995. Ped Pulmonolgy. 20: 362-68 • No studies have shown any safety concerns or adverse effects with dexamethasone even at doses up to 0.6 mg/kg • Current recommendation is Dex 0.6 mg/kg PO • Ausejo et al. 1999. BMJ. 319: 595-600

32. Does giving steroids early in the ED affect disposition or Outcome? • At least 4 RCT’s, all suggesting improved clinical status with early steroids • 1 study only had 80% power to detect 67% difference in admission rate • Johnson et al. 1996. Arch Ped Adol Med 150: 349-55 • 2 suggest decreased admission rate • Johnson et al. 1998. N Engl J Med. 339: 498-503 • Klassen et al. 1994. N Engl J Med. 331: 285-89 • 1 study suggest no sig benefit from nebulized budesonide in addition to PO dex • Klassen et al. 1998. JAMA 279: 1629-32 • Steroids early appear to be helpful

33. Who do you admit? • Most pts can be discharged • Admission for: • Marked distress / ill looking • Hypoxia • Dehydration • Poor Tx response / persistent stridor + other Sx • Other medical co-morbidities (prem, cardiac, pulm) • Young age • Social: far from hospital, questionable f/u, scary story, anxious parents

34. Who do you intubate? • Very rare since advent of steroids • Use ½ size smaller than calculated • No clear guidelines; exercise clinical judgment

35. Case • 13 yo boy w/ known asthma presents w/ runny nose, cough, and inc’d SOB • O/E: 373 / 100 / 22 / 96% RA • Mild exp wheezes • PEF 300 compared to usual of 375

36. What’s your DDx for wheezing? • Asthma • Foreign body • Bronchiolitis • CHF • Anatomic (vascular ring, laryngomalacia..) • CF • Pertussis • Pneumonia

37. Asthma • Most common chronic dz of children • Rising M + M: mortality doubled 1977-85 • Chronic inflammatory dz characterized by exacerbations + remissions, w/ airway obstruction partially reversible w/ meds • Specific triggers • Goal of ED care is to coordinate w/ existing care plan as much as possible

39. What’s your approach? • Initial assessment • ABC’s • Initial management • Oxygen, bronchodilators, steroids, • Identify risk factors and assess Tx response • Disposition and F/U

40. Prior sudden exacerbations Prior intubations / ICU stays >2 admissions in past year >3 ED visits in past yr Admission or ED visit in past month >2 ventolin inhalers per month Currently on, or recent weaning from, steroids Poor perception of airflow obstruction Co-morbid disease Low SE status, urban residence Psychiatric dz Sensitivity to Alternaria Mortality Risk Factors

41. Clinical Scoring Systems • Most common is pulmonary index • Based on physical exam findings including RR, wheezing, I-E ratio, and use of accessory muscles • None have sufficient validation to be used in disposition decisions

42. Pulmonary Function Tests • Formal PFT’s are best to measure degree of obstruction but not convenient in ED • PEF commonly used • correlates w/ FEV1 • Effort-dependant, pt needs to stand • Compare w/ personal best or standard tables PEF pred Severity <30% possibly life-threatening <50% severe 50-80% moderate >80% mild

43. Pulse Oximetry + Oxygen • No official agreement on normal values: • NAEPEP states anyone <90% should get O2 • Common practice in the region is <92% • Acute asthma pts w/ SaO2 <95% were more likely to be admitted and more likely to return to ED if discharged • Geelhoed et al. 1990. J Ped. 117: 907-09 • SaO2 <93% found to be 35% sensitive and 93% specific fro admission • Mayefsky and el_Shianway. 1992. Ped Emerg Care 8: 262-4 • Limitations of pulse oximetry: • Dec’d O2-carrying capacity • Low perfusion state • Provides no information on ventilation

44. b-agonists • Salbutamol is 1st line therapy in asthma • Epinephrine has no benefit over salbutamol • Klassen et al. 2000. Acad Emerg Med 7: 1097-103 • Mechanism of action: • Relax bronchial smooth muscle • Increase secretion of water from mucous glands • Increase mucociliary clearance • Controversies: • Route of administration in ED • New pure R isomers (levalbuterol) • Continuous therapy

45. MDI or Nebulizer? • Nebulizers enormously popular in ED • Cost of nebulizer is ~50% greater • Most people use MDI’s at home • 5 studies show either equivalence, or even superiority of MDI over nebulizer • One double-blind RCT in 5-17 yo subjects showed no difference • Schuh et al. 1999. J Ped. 135: 22-27 • Similar study in pts aged 1-4 yo showed dec’d admission rate + less wheezing in MDI group • Leversha et al. 2000. J Ped 136: 497-502 • Ploin et al. 2000. Pediatrics. 106: 311-17 • MDI makes more sense in ED

46. IV Salbutamol • Few well designed trials • Cardiotoxicity: need to monitor cardiac funxn + K+ • Rationale: may get to non-ventilated lung areas • One double-blind RCT of IV salbutamol in addition to continuous nebulized salbutamol showed more rapid improvement than control group • Did not follow cardiac enzymes • Browne et al. 1997. Lancet. 349: 301-305 • Current recommendation is to consider early on in severe Tx-refractory cases

47. Continuous b-agonist therapy • Usually administered as 0.5 mg/kg/h , to a maximum of 15 mg • Requires cardiopulmonary monitoring • some studies (mostly adult) showing improved asthma scores, but no difference in PEF’s, admission rates, or adverse effects • Besbes-Ouanes et al. 2000. Ann Emerg Med 36:198-203 • Jury still out – may consider if tx-refractory

48. Levalbuterol • Salbutamol (albuterol) = R + S isomers • R isomer  bronchodilation • S isomer  bronchoconstriction • Manifests clinically as tolerance after repeated use • Levalbuterol is pure R isomer • ~5x cost of salbutamol • One double-blind crossover study of 33 kids suggests better than or equivalent to salbutamol w/ less side effects, but in stable pts (not ED setting) • Gawchik et al. 1999. J Allergy Clin Immunol 103: 615-21 • No head-to-head trials in ED setting • Not indicated for use at this time; needs further study

49. Anti-Cholinergics • Ipratropium bromide • Similar to atropine; bromide group prevents systemic effect • Inhibits Ach-mediated bronchoconstriction • Only useful in addition to b-agonist • Takes 60-90 min to reach peak effect • Given as 250 mg x3 doses or 500 mg x2 doses by nebulizer over 1 hour; repeat q2-4h prn • One meta-analysis and a Cochrane review show: • Multiple doses (but not single doses) decrease admissions in mod - severe exacerbations w/ NNT of 12 • No conclusive evidence for use in mild-moderate cases • Plotnick and Ducharme. 1998. BMJ. 317: 971-977 • Plotnick and Ducharme. 2002. Coch Data Sys Rev. Issue 1 • NAEPP: use in severely ill kids, and those not responding to high dose b-agonist therapy

50. Steroids • Meta-analysis of 30 RCT’s + recent Cochrane review show: • Early steroids dec’d admission rates (NNT = 8) • IV = PO in efficacy; no significant adverse effects • Rowe et al. 1992. Am J Emerg Med. 10: 301-310 • Rowe et al 2002. Coch Data Sys Rev. Issue 1 • Speed resolution of obstruction • Potentiate effects of b-agonists • Steroids prevent relapse w/ NNT 13, and decrease need for b-2 agonists • Rowe et al 2002. Coch Data Sys Rev. Issue 1 • Indicated for most pts in ED