IV Access
Peripheral IV is the standard first-line vascular access. Use the largest vein you can access in the most proximal location feasible.
Gauge Selection
- 14g or 16g: Trauma, hemorrhage, rapid fluid administration
- 18g: General use — most medications, moderate fluid rates
- 20g–22g: Smaller veins, maintenance fluids, medication administration in non-urgent settings
Sites (best to worst)
- Antecubital fossa (AC): Largest peripheral vein — go here first in emergencies
- Forearm veins: Cephalic, basilic — good alternatives
- Hand veins: Last resort — smaller, more painful, slower
- External jugular: Large, accessible in arrests — requires 45° Trendelenburg
Intraosseous (IO) Access
IO access drills directly into the bone marrow cavity, which acts as a non-collapsible vascular space. Medications and fluids reach the central circulation within seconds — comparable to a central line. Use when IV access cannot be obtained in a critical patient.
Sites
- Proximal tibia: Most common. 2 cm below and medial to the tibial tuberosity. Best for most adults.
- Proximal humerus: Good if tibia inaccessible. Insert perpendicular to bone, 1 cm above surgical neck.
- Distal tibia: 2 cm proximal to medial malleolus. Alternative site.
- Sternal: FAST-1 device only. Rapid access in arrests.
In a conscious patient, IO insertion is painful but tolerable. Infusion through IO is extremely painful due to intraosseous pressure. Flush with 10 mL of 2% lidocaine (preservative-free), wait 60 seconds, then infuse slowly. Don't skip this step.
IV Fluids
| Fluid | Type | Use | Notes |
|---|---|---|---|
| Normal Saline (NS) | Isotonic crystalloid | General resuscitation, medication diluent | Large volumes cause hyperchloremic acidosis. Still widely used. |
| Lactated Ringer's (LR) | Balanced crystalloid | Trauma, burns, hemorrhagic shock | More physiologic than NS. Preferred for trauma resuscitation. |
| D50W | Hypertonic dextrose | Hypoglycemia (<50 mg/dL) in unconscious patient | 25g dextrose (50 mL of 50%). Confirm IV patency first — extravasation causes tissue necrosis. |
| D5W | Hypotonic | Drug dilution only | Not for volume resuscitation — distributes into cells, doesn't stay intravascular. |
Paramedic Drug Reference
| Drug | Indication | Dose | Key Points |
|---|---|---|---|
| Epinephrine 1:10,000 | Cardiac arrest | 1 mg IV/IO q3–5min | Increases coronary perfusion pressure |
| Epinephrine 1:1,000 | Anaphylaxis | 0.3–0.5 mg IM; 0.1 mg IV for refractory | IV epi for arrest or refractory anaphylaxis only |
| Amiodarone | Refractory VF, VT | 300 mg IV push; 150 mg repeat | Broadest antiarrhythmic |
| Adenosine | Stable SVT | 6 mg rapid push; 12 mg ×2 | Rapid push + flush at AC or above |
| Atropine | Symptomatic bradycardia | 0.5 mg IV q3–5min, max 3 mg | Doesn't work for complete heart block |
| Dopamine | Cardiogenic shock, bradycardia | 5–20 mcg/kg/min infusion | 5–10 = beta (inotropic); >10 = alpha (vasopressor) |
| Norepinephrine | Septic/distributive shock | 0.1–0.5 mcg/kg/min, titrate | First-line vasopressor for septic shock |
| Fentanyl | Pain management | 1–2 mcg/kg IV/IM/IN, titrate | Preferred over morphine in ACS — fewer hemodynamic effects |
| Morphine | Severe pain | 2–4 mg IV, titrate | Histamine release — causes nausea, vasodilation. Avoid in ACS. |
| Midazolam | Sedation, seizures, RSI | 1–5 mg IV/IM; 0.1–0.3 mg/kg RSI | Respiratory depression risk — have airway equipment ready |
| Diazepam | Status epilepticus | 5–10 mg IV/IM/rectal | Second-line to midazolam in prehospital |
| Naloxone | Opioid reversal | 0.4–2 mg IV/IM/IN, titrate | Titrate to ventilation, not full reversal |
| Aspirin | Suspected MI | 324 mg PO chewed | Antiplatelet — give early in all suspected ACS |
| Nitroglycerin | ACS, pulmonary edema | 0.4 mg SL q5min ×3 | Contraindicated: SBP <100, recent ED meds, RV MI |
| Dextrose 50% | Symptomatic hypoglycemia | 25 g (50 mL) IV push | Confirm patency — tissue necrosis if extravasates |
| Sodium Bicarbonate | Severe acidosis, TCA OD, hyperkalemia | 1 mEq/kg IV push | Not routine in arrest — correct underlying cause first |
IV is preferred when access is available. IO is equivalent in emergencies. IM is slower but doesn't require vein access (epi, midazolam, glucagon). IN (intranasal) via MAD device: naloxone, midazolam, fentanyl — useful in pediatrics and uncooperative patients. SL (sublingual): nitroglycerin — absorbed through oral mucosa.