Procedural Sedation & Analgesia (PSA)
Comprehensive emergency procedural sedation: pre-sedation risk assessment, ACEP fasting policy (why NPO status does not delay emergency PSA), sedative pharmacology (Propofol, Ketamine, Ketofol, Etomidate), continuous waveform capnography interpretation, and airway rescue protocols.
Resuscitation Quick Ribbon (First 2 Minutes)
Bottom-Line Clinical Pearl
Emergency Procedural Sedation & Analgesia (PSA) is distinct from elective anesthesia: fasting guidelines (NPO status) do NOT prohibit emergency sedation in painful dislocations, reductions, or procedures (ACEP Clinical Policy). Continuous waveform capnography is mandatory—it detects hypoventilation and airway obstruction minutes before pulse oximetry desaturates. Choose agent based on hemodynamics and duration: Ketamine (dissociative, preserves airway reflexes and BP), Propofol (rapid on/off, muscle relaxation, drops BP), Ketofol (1:1 combination balancing BP and emesis), Etomidate (hemodynamically neutral for short reductions).
Procedural sedation safely accomplishes painful emergency interventions (joint reductions, abscess drainage, cardioversion, complex laceration repair) while minimizing patient distress and preventing physical trauma. The American College of Emergency Physicians (ACEP) Clinical Policy explicitly confirms that emergency procedural sedation should NOT be delayed based solely on fasting time; clinical trials have repeatedly demonstrated zero correlation between NPO duration and pulmonary aspiration during emergency PSA.
| Evaluation Domain | Key Checklist Components | High-Risk Red Flags Mandating Caution |
|---|---|---|
| Airway Anatomy | Mallampati score, thyromental distance (< 3 fingerbreadths), retrognathia, macroglossia, neck mobility | Severe obesity, prior failed intubation, facial burns or trauma, active stridor. |
| Cardiopulmonary Status | Baseline blood pressure, heart rate, room air SpO2, lung auscultation | Preexisting hemodynamic instability (hypotension), decompensated heart failure, severe COPD/asthma. |
| ASA Physical Status | Class I (Healthy) to Class IV (Severe systemic disease that is a constant threat to life) | Patients in ASA Class III or IV have significantly higher complication rates; consider regional anesthesia. |
| Equipment Preparation (SOAP ME) | Suction (rigid Yankauer running), Oxygen (nasal cannula + BVM), Airway (nasal/oral airways, supraglottic device, ETT), Pharmacy, Monitors, EtCO2 | Never administer sedation without working suction and age-appropriate bag-valve-mask at the bedside. |
| Agent | Induction Dose | Onset & Duration | Clinical Advantages & Best Uses | Adverse Effects & Cautions |
|---|---|---|---|---|
| Propofol (Diprivan) | 0.5–1.0 mg/kg IV initial bolus, then 0.25–0.5 mg/kg q2–3min | Onset: 30–60 sec Duration: 5–10 min | Rapid onset and clear awakening; excellent muscle relaxation (ideal for large joint reductions: shoulder, hip). Antiemetic. | PROFOUND HYPOTENSION (arteriolar and venous dilation); respiratory depression and apnea. Avoid in hypovolemia/shock. |
| Ketamine (Ketalar) | 1.0–1.5 mg/kg IV (or 3–4 mg/kg IM if no IV access) | Onset: 60 sec Duration: 15–25 min | Dissociative sedation: maintains airway reflexes, spontaneous respirations, and sympathetic tone. Potent analgesia. | Emergence agitation / delirium (treat with low-dose midazolam); hypersalivation; transient tachycardia and hypertension. |
| Ketofol (1:1 Ketamine + Propofol) | 0.5 mg/kg IV bolus (0.25 mg/kg of each drug), titrate 0.25 mg/kg | Onset: 45 sec Duration: 10–15 min | Synergistic combination: Ketamine maintains hemodynamics while Propofol suppresses nausea and emergence reactions. | Lower incidence of hypotension compared to propofol alone; titrate slowly to avoid hypoventilation. |
| Etomidate (Amidate) | 0.1–0.15 mg/kg IV (lower than RSI dose) | Onset: 30–60 sec Duration: 5–10 min | Hemodynamically neutral: zero effect on blood pressure or myocardial contractility. Excellent for elderly/unstable. | High incidence of myoclonus (can interfere with orthopedic reduction); brief transient adrenal suppression. |
Continuous end-tidal CO2 (EtCO2) monitoring via dedicated nasal cannula is the gold standard for patient safety during procedural sedation. Capnography provides real-time instantaneous detection of hypoventilation, airway obstruction, and apnea, alerting the clinician 2 to 3 minutes before pulse oximetry registers arterial hypoxemia.
| Capnography Waveform Pattern | Underlying Pathophysiology | Immediate Stepwise Airway Rescue Action |
|---|---|---|
| Progressive Loss of Waveform Height / Rising EtCO2 | Hypoventilation / Central respiratory depression | Tactile stimulation; verbal prompt ('take a deep breath'); decrease or pause sedative titration. |
| Flatline Capnogram with Persistent Chest Movement | Upper airway obstruction (soft palate / tongue collapse) | Perform immediate Bimanual Jaw Thrust and Head-Tilt Chin-Lift; place soft Nasopharyngeal Airway (NPA). |
| Flatline Capnogram with Absent Chest Movement | Central apnea / Sedative overdose | Deliver gentle bag-valve-mask (BVM) ventilations (1 breath q5–6 sec); maintain high-flow oxygenation. |
| High-Pitched Stridor + Flattened Incomplete Waves | Laryngospasm (vocal cord adduction) | Perform Larson's Maneuver (firm bilateral pressure at the laryngospasm notch behind earlobes while applying positive airway pressure BVM with 100% O2). If refractory: Succinylcholine 0.2–0.5 mg/kg IV. |
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