Critical Care Procedures & Vascular Access
Essential emergency critical care procedures: ultrasound-guided internal jugular, subclavian, and femoral central lines, arterial line cannulation and pulse pressure variation, humeral vs tibial intraosseous insertion, emergency lumbar puncture, and paracentesis/thoracentesis.
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Ultrasound guidance is mandatory for internal jugular and femoral central venous catheterization (decreases complications and attempts). Subclavian CVC has the lowest infection and DVT rate, but highest pneumothorax risk. For rapid high-volume resuscitation, a 16G or 14G peripheral IV or an 8.5 Fr Cordis introducer achieves far higher flow rates than a triple-lumen catheter (Poiseuille's law). Proximal humerus IO achieves flow rates of 5,000 mL/hr under pressure bag and delivers drugs directly to the right atrium in seconds.
The primary indications for emergency central venous catheterization (CVC) are administration of concentrated vasopressors, hypertonic solutions, transvenous cardiac pacing, and advanced hemodynamic monitoring. For volume resuscitation in hemorrhagic shock, short, large-gauge catheters (14G peripheral IV or 8.5 Fr Cordis) are mandatory—flow rate is inversely proportional to catheter length and directly proportional to the fourth power of the radius (Poiseuille's Law).
| Anatomical Site | Ultrasound Guidance Landmark | Advantages | Complications & Contraindications |
|---|---|---|---|
| Internal Jugular (IJ) | Transverse linear probe over apex of Sedillot's triangle (between sternal and clavicular heads of SCM) | Direct ultrasound visualization; compressible; lowest pneumothorax risk under ultrasound guidance. | Carotid artery puncture; risk of neck hematoma in coagulopathy; difficult in rigid C-collars. |
| Subclavian (Infraclavicular) | Longitudinal / in-plane view along axillary vein transitioning under clavicle | LOWEST INFECTION RATE (CRBSI); lowest venous thrombosis rate; patent during severe shock/hypovolemia; comfortable for patient. | Non-compressible behind clavicle; highest pneumothorax rate. Avoid in severe coagulopathy. |
| Femoral Vein | Transverse linear probe 1–2 cm inferior to inguinal ligament; vein is medial to femoral artery | Rapid, easy access during active chest compressions/CPR; does not interfere with airway or thoracic procedures. | HIGHEST INFECTION AND DVT RISK; non-compliant in ambulatory patients; remove or replace within 24–48 hours. |
| Large-Bore Introducer (Cordis 8.5 Fr) | Internal Jugular or Femoral vein cannulation | Extreme flow rate (> 800 mL/min gravity flow); accommodates transvenous pacing wire or rapid infuser tubing. | Risk of catastrophic air embolism if open to air; always keep valve cap sealed. |
Intraosseous access provides rapid, non-collapsible vascular access into the medullary venous plexus, achieving therapeutic drug concentrations identical to central venous catheterization within seconds:
| Anatomical IO Site | Specific Anatomical Landmark | Needle Size Selection | Clinical Advantages & Flow Dynamics |
|---|---|---|---|
| Proximal Humerus (Adult) | Greater tubercle of humeral head (internally rotate arm; place hand over umbilicus; palpate prominent bone 1–2 cm above surgical neck) | Yellow Needle (45 mm / 15 gauge) | HIGHEST FLOW RATE: Up to 5,000 mL/hr under 300 mmHg pressure bag. Drugs reach the right atrium in < 5 seconds via superior vena cava. Less painful than tibial site. |
| Proximal Tibia (Adult / Ped) | 2 cm medial to tibial tuberosity on the flat anteromedial surface of the tibia | Blue (25 mm) or Yellow (45 mm in obese); Pink (15 mm in pediatrics) | Easiest anatomical landmark; minimal soft tissue; lowest risk of dislodgement during CPR. |
| Distal Tibia | 2 cm proximal to the medial malleolus on flat medial surface | Blue Needle (25 mm) | Alternative site in trauma when lower extremity trauma precludes proximal tibia. |
Pain Management in Awake IO Patients: In conscious patients, high-pressure fluid infusion through bone marrow causes agonizing, visceral bone pain. Prior to flushing or administering fluids, slowly infuse 40 mg (2 mL of 2% preservative-free Lidocaine) through the IO catheter over 2 minutes, let sit for 60 seconds to anesthetize the marrow cavity, then flush with 10 mL normal saline.
Emergency Lumbar Puncture (LP) evaluates for suspected bacterial/viral meningitis, encephalitis, and subarachnoid hemorrhage. Position patient in the lateral recumbent position with hips and knees flexed to open intervertebral spaces. The intercristal line connecting the superior iliac crests identifies the L4 spinous process or L4–L5 interspace (well below the termination of the spinal cord at L1–L2 in adults).
| Condition | Opening Pressure | WBC Count & Differential | Protein Concentration | Glucose Ratio (CSF / Serum) |
|---|---|---|---|---|
| Normal Adult | 60–200 mmH2O | < 5 cells/uL (100% mononuclear) | 15–45 mg/dL | 0.6 (>= 60% of serum glucose) |
| Acute Bacterial Meningitis | ELEVATED (> 200–300 mmH2O) | MARKEDLY ELEVATED (> 1,000–10,000/uL with > 80% PMNs) | ELEVATED (> 100–500 mg/dL) | MARKEDLY DECREASED (< 0.4; often < 40 mg/dL) |
| Viral Meningitis / Encephalitis | Normal to mildly elevated | Mildly elevated (50–500/uL; lymphocytic predominance) | Normal to mildly elevated (50–100 mg/dL) | NORMAL (> 0.6) |
| Subarachnoid Hemorrhage (SAH) | Elevated | Persistent RBCs in Tube 1 and Tube 4 (no clearing); Xanthochromia present after 6–12h | Elevated (erythrocyte protein breakdown) | Normal |
| Traumatic Tap (Puncture Vessel) | Normal | RBC count clears by > 50–70% between Tube 1 and Tube 4; NO xanthochromia on centrifugation | Normal or mildly elevated | Normal |
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