Hemodynamic monitoring in specific circumstances including - Expected significant blood loss (multilevel spine, trauma, major ortho surg) - Clinically unstable patients (severe or labile hypertension or hypotension with concern for sepsis, cardiogenic shock, ect) - Surgical need for tight BP control (neurosurgical/vascular procedures; CNS aneurysm coiling, carotid surg) - Measurement of MAP crucial to derive cerebral perfusion pressure or coronary perfusion pressure (CPP): Neurosurgery, cardiac, beach-chair, semi-Fowler's ENT

Frequent blood sampling for blood gas analysis &/or diagnostic tests to guide intraoperative management (electrolytes, iCal, Lactic acid, Hb, coagulation studies, TEG, ACT, PTH, ect)

Unable to obtain a non-invasive blood pressure or NIBP ineffective/impractical - Morbidly obese patients where NIBP cuff pressures are unreliable - Significant concern for NlBP cuff trauma; patient with very low PLT count or high INR - Cases where arm positioning make cuff potentially traumatic to med nerve (thoracotomy)

Contraindications: - Abnormal Allen's test - Infection at desired site - Thrombus or traumatic injury at or proximal to desired site - Altered anatomy at desired site (AV fistula, vascular graft, prior surgeries) - Active Raynaud syndrome or thromboangiitis obliterans (particularly in radial)

Common Arterial Line Supplies: - Towel rolled into a cylinder (placed under the hand to put the wrist into extension) - Chlorhexidine prep - Sterile Gloves - Sterile towels/covering - Transparent dressing - Sterile gauze - Plastic tape - Pre-flushed A-line tubing with 3 Way Stopcock & sterile 10cc NS syringe attached - Arterial Catheter (common brands; Arrow, Angiocatheter; note size & gage vary depending on the artery you are trying to cannulate) (roll 1 into wrist support) - +/- US Gel & probe cover - +/- benzoin adhesive

Preparation: - Check collateral perfusion with Allen test:

  • compress ulnar/radial, have patient make fist until hand blanches; release ulnar or radial compression, if blanching resolves within 5sec reassuring allens test. Repeat releasing the other artery.

- 1% Lidocaine with 27-30g needle if pre-induction a-line planned - Optimize Ergonomics (Bed Height) - Position Wrist placed rolled up towel under wrist to put into dorsiflexion (brings radial artery closer to skin) & secure hand to arm-board or other surface - Sterilize field with Chlorhexidine stick - Put on sterile gloves then place sterile drape/towels around wrist keeping only the cleaned skin in view - If self contained or Integrated Arterial Catheter, check to make sure wire threads smoothly

Blind Approach: - Locate pulse Palpate w/ Tips of Finger (not pads) & trace trajectory - Holding the arterial catheter like a pencil Bevel UP insert the needle at a 30-45° angle - Advance until flash with pulsatile blood or if no flash widthdraw needle without exiting skin and either change the angle of approach or fan medially or laterally based on the patients anatomy until you have pulsatile flash. - Once (+) blood return flatten angle to 10-15° & advance slightly to remain within lumen of vessel If using Angiocatheter: - Remove introducer leaving catheter in place if continues to have pulsatile flow threat guidewire - NOTE: Guidewire should thread smoothly. Stop if meeting resistance at risk of dissecting artery wall If using Integrated Arterial Catheter (Arrow): - ***

- After guidewire in place thread the catheter over the wire into the vessel (commonly a twisting motion is used) - Once catheter in vessel, hold proximal pressure and remove guidewire (pulsatile flow) - Connect prepared a-line tubing w/ stopcock off to PT (NO Bubbles) - Open stopcock to patient and draw back until blood in syringe & flush (be careful to NEVER inject bubbles through an A-line) - Turn stopcock off to patient, hold catheter in place at skin & carefully clean site of blood/gel then apply dressing - Connect arterial line transducer, level & zero


Practical Skills Drawing Labs Off A-line: -