Ketamine and Atropine for Procedural Sedation

Introduction to Ketamine and Atropine

• The American College of Emergency Physicians recommends administering ketamine at 1.5-2 mg/kg IV (or 4 mg/kg IM) combined with atropine 0.01 mg/kg for procedural sedation in children, demonstrating superior efficacy and safety 1

Intravenous Dosing Protocol

• Ketamine 1.5-2 mg/kg IV is the optimal dose, with only 5.5% of patients requiring additional doses compared to 54% with lower 1 mg/kg dosing, according to the American College of Emergency Physicians 1
• Onset of adequate sedation occurs within 30-96 seconds 1, 2
• Success rate for procedural completion is 98.9% with appropriate dosing, as recommended by the American College of Emergency Physicians 2
• Average recovery time is 84 minutes (range 22-215 minutes) 1

Intramuscular Dosing Protocol

• Ketamine 4 mg/kg IM combined with atropine 0.01 mg/kg provides faster onset and shorter discharge time compared to other sedatives, based on emergency medicine guidelines 1
• The 4 mg/kg dose is preferred for procedural sedation based on emergency medicine guidelines from the American College of Emergency Physicians 3, 4

Atropine Coadministration

• Atropine 0.01 mg/kg (minimum 0.1 mg, maximum 0.5 mg) should be administered with ketamine to prevent hypersalivation and potentially reduce post-procedural vomiting, as recommended by the American College of Emergency Physicians and supported by the FDA 3, 4

Monitoring Requirements

• Continuous vital sign monitoring is mandatory during ketamine administration, including pulse oximetry, heart rate, and blood pressure, according to the American College of Emergency Physicians 1, 2

Expected Adverse Effects

• Emesis occurs in 7-8% of patients 1, 2
• Nausea occurs in 4-5% of patients 1
• Recovery agitation occurs in 7.1% of pediatric patients, higher in younger children 5
• Laryngospasm occurs in 0.9-1.4% of patients 2
• Airway complications occur in 1.4% of patients without requiring intubation or causing sequelae 4

Adjunctive Midazolam Consideration

• Midazolam 0.05 mg/kg IV may be added to reduce emergence reactions, particularly in adults, as recommended by the American College of Emergency Physicians 2, 5

Critical Pitfalls to Avoid

• Underdosing ketamine is the most common error, resulting in inadequate sedation requiring supplemental doses in over 50% of patients, according to the American College of Emergency Physicians 1, 2

Ketamine for Procedural Sedation

Pharmacologic Advantages

• Ketamine preserves airway reflexes and respiratory drive, a critical safety advantage over midazolam which causes dose-dependent respiratory depression, as noted by the American College of Emergency Physicians 6, 7

Limitations of Midazolam

• Midazolam's major side effect is respiratory depression, with deaths reported when combined with opioids, which would be necessary to achieve analgesia comparable to ketamine, according to the American College of Gastroenterology 6
• Apnea may occur up to 30 minutes after the last midazolam dose, requiring prolonged monitoring, as recommended by the American College of Gastroenterology 6
• Midazolam alone provides no analgesia, necessitating additional opioid administration that increases respiratory depression risk synergistically, as reported by the American College of Gastroenterology 6

Special Populations

Pediatric Considerations

• Ketamine is designated as a Level A recommendation by the American College of Emergency Physicians for safe administration to children for procedural sedation, with a high parental satisfaction rate 7

Adult Considerations

• The combination of midazolam and ketamine receives a Level B recommendation for effectiveness in adult ED procedural sedation, as noted by the American College of Emergency Physicians 7

Ketamine‑Based Sedation for Pediatric Facial Suturing

Dosing and Efficacy

• Optimal IV ketamine dose: 1.5–2 mg/kg provides adequate sedation in >94 % of children, reducing the need for rescue dosing compared with 1 mg/kg (supplemental dosing required in 54 % vs 5.5 %). 8
• Rapid onset: IV ketamine 1.5–2 mg/kg combined with atropine 0.01 mg/kg produces procedural readiness within 30–96 seconds, allowing immediate start of suturing. 8
• IM alternative: When IV access is unavailable, ketamine 4 mg/kg IM yields onset in 3–4 minutes and maintains optimal sedation for ≈37 minutes. 8

Safety and Adverse Events

• Respiratory safety: Properly dosed ketamine does not cause respiratory depression or hypoxemia in pediatric patients. 8
• Avoiding adjunct sedatives: Adding midazolam to ketamine increases the risk of respiratory depression and should be avoided for brief facial suturing unless a specific indication exists. 9
• Propofol caution: Propofol is not preferred for this procedure because of its narrow therapeutic range and unpredictable cardiorespiratory depression, necessitating full monitored anesthesia care. 10

Monitoring and Personnel Requirements (American Academy of Pediatrics)

• Continuous monitoring: Pulse oximetry (maintain SpO₂ > 93 % on room air), capnography for moderate‑to‑deep sedation, and a dedicated observer separate from the proceduralist are required. 11
• Patient assessment: Children should be classified as ASA I or II and screened for airway abnormalities (e.g., tonsillar hypertrophy) before sedation. 9
• Equipment readiness: Age‑appropriate airway rescue equipment (bag‑valve‑mask, oral/nasal airways, laryngoscope, endotracheal tubes) must be immediately available, and staff must be trained in pediatric airway management. 9

Adjunctive Measures

• Topical/local anesthesia: Application of lidocaine‑epinephrine‑tetracaine (LET) or buffered lidocaine to the wound reduces overall sedation requirements and improves procedural comfort. 12

Post‑Procedure Care

• Discharge instructions: Caregivers should receive clear written instructions, be warned that transient ataxia occurs in ~7–8 % of children (lasting 0.5–2 hours), and ensure a responsible adult accompanies the child home. [12][8]9
• Pain management: If moderate pain is anticipated, prescribe around‑the‑clock analgesia. 12

Midazolam Adjunct Reduces Emesis in Pediatric Procedural Sedation

Evidence from Clinical Studies

• Adding a single intravenous dose of midazolam 0.05 mg/kg to ketamine‑based procedural sedation in children (particularly those > 10 years old) is associated with a trend toward lower incidence of post‑procedure emesis compared with ketamine alone, as reported in two studies published in Annals of Emergency Medicine (2004 and 2005)【13】【14】. (Evidence level not explicitly stated; observational data).