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Pediatric Rapid Sequence Intubation February 26, 2004 Case A 4-yo child is an unrestrained front seat passenger in a motor vehicle crash. Child was alert and talking coherently at the scene. On arrival to ER the child is unresponsive. RR is 12 with pauses in breathing. SaO2 is 100% on 5 L O2. Air entry is normal bilaterally. HR is 90. BP is 130/84. Central and peripheral pulses are strong with a cap refill of 2 seconds and warm pink extremities. Case He has no purposeful movements. He exhibits flexion posturing in response to pain. He has no gag. His pupils are 3 mm and briskly respond to light. He has a large scalp contusion but no obvious midfacial or mouth injuries. His abdomen is soft; there are no deformities and no obvious external bleeding. Definition Rapid sequence induction of anaesthesia in order to – eliminate or attenuate the physiological reflexes to laryngoscopy and intubation – prevent pulmonary aspiration Physiological consequences of laryngoscopy and intubation Afferent pathways activated by – Physiological insults: hypoxia, hypercarbia – Anatomical insults: oral airway, laryngoscopy, ETT Efferent response – CNS: raised ICP, raised IOP – CVS: bradycardia (parasympathetic) tachycardia, hypertension (sympathetic) – Resp: apnea, gag, cough, sneeze, swallow, laryngospasm, bronchospasm Pulmonary Aspiration Syndrome Always assume a full stomach in RSI Incidence of vomiting 36-44% (aspiration 2-4%) Higher risk in children: – aerophagia during crying – strenuous diaphragmatic activity – shorter esophagus Complications include: – Bronchospasm – Pneumonitis Pediatric Anatomical Considerations Large head Small nares Small mouth Large tongue Larynx Adult – Opposite C4 - C6 Child – Opposite C2 - C3 Larynx Adult – Cylindrical Child – Funnel-shaped Vocal Cords Adult – Horizontal Child – Sits in a slant Epiglottis Adult – Relatively smaller – Stiffer cartilage Child – Relatively larger & longer – Floppy Trachea Adult – Longer Child – Shorter Airway diameter Adult – Smallest diameter between vocal cords Child – Smallest diameter at cricoid ring (just below vocal cords) Pediatric Physiological Consideration FRC smaller Airway Resistance Airway smaller and floppier Resistance exponentially higher Oxygen Consumption Oxygen consumption is higher: – 6-8 ml/kg in infants – 3-4 ml/kg in adults More prone to hypoxia Chest Wall Compliance Compliance higher Retractions are common RSI - preparation Brief Hx and PE AMPLE – e.g. NMD – e.g. previous meal – e.g. Hx of HI Exam: – e.g. anatomic challenges to intubation Personnel (1) Airway (2) Medications (3) Monitoring and Cricoid Pressure Equipment SOAP ME Suction Oxygen Airway Pharmacology Monitoring Equipment Suction YANKAUER tip Tracheal suction catheter Oxygen high-flowmeter connected to a functioning bag-valve- mask devise – self-inflating bag – anaesthesia bag Airway Oral airway Face masks with cushion seal ETT – size: 4 + (age/4) – uncuffed for < 8 year olds: 3 + (age/4) Airway Stylet Magill forceps Laryngoscopes – Handle – Blade straight (Miller) for infants curved (Macintosh) for > 1 yr Pharmacology Premedication - anticholinergics – Atropine IV 0.02 mg/kg (min 0.1mg; max 1.0mg) Indications: – < 1 yr – 1-5 yo receiving Sux – > 5 yp receiving 2nd dose of Sux Consider for: – Bradycardic child – Ketamine use Pharmacology Premedication - analgesia – Fentanyl IV 2-4 ug/kg S/E: – Chest wall rigidity – Raised ICP – Hypotension Pharmacology Sedatives – Ketamine IV 2 mg/kg Onset w/i 1 min & anaesthesia for 10 to 15 min Pulmonary vasodilator Contraindicated in head injury – Thiopental IV 2-4 mg/kg Onset w/i 1 min & anaesthesia for 5-10 min Cerebral vasoconstrictor Contraindicated in asthma Pharmacology Muscle relaxation – Succinylcholine IV 2 mg/kg fastonset of action (30 s) recovery w/i 5-10 min S/E: fasciculations, hyperkalemia, raised ICP, etc. only NMB agent approved for IM use (4 mg/kg) – Rocuronium IV 1 mg/kg fastonset of action (30 sec) recovery w/i 40 min Monitoring Equipment Continuous cardiorespiratory monitoring noninvasive blood pressure pulse oximetry end-tidal CO2 RSI - technique Airway patency opened by chin lift & jaw thrust – ONLY JAW THRUST IN TRAUMA oral pharynx suctioned +/- oral airway inserted Pre-oxygenation 100% oxygen for 2-5 min Creates an oxygen reservoir in the lungs Avoid BMV to prevent gastric distention If no effective ventilation spontaneously, may BMV + cricoid (if sedate) Medication Premedications – Anticholinergics – Analgesics Sedatives Cricoid pressure +/- BMV NMB Tracheal Intubation Intubation – blade insertion – depth of ETT insertion ( AGE/2 ) + 12 OR internal di. Of ETT x 3.5 Tracheal Intubation confirmation of tracheal intubation – Primary Chest rise Equal A/E – Secondary SaO2 & EtCO2 – Definitive CXR secure the tube ng placement – OG IN HI ongoing sedation +/- paralysis Conclusion consider the differences between the child and the adult in anatomy, physiology, drug metabolism, and emotional response to injury standardize & simplify the procedure Reference Lee BS. Pediatric Airway Management. Clinical Pediatric Emergency Medicine. 2001 Jun; 2(2); 91-106.
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