Patient Assessment and Monitoring
Scope of assessment
Pre-procedure assessment establishes baseline data and identifies risk: history of prior access complications, anticoagulation, allergies (including chlorhexidine and lidocaine), renal function, and the indication and urgency of access. Physical assessment includes inspection of both arms for existing accesses, scars, edema, and skin integrity, plus bilateral blood pressure and pulse. Document baseline vital signs and distal neurovascular status so post-procedure changes can be attributed.
Intraprocedural monitoring
Continuous observation covers patient comfort, sedation level, vital signs at defined intervals, and early signs of vasovagal response (diaphoresis, pallor, nausea, bradycardia). Local anesthetic toxicity presents with perioral tingling, tinnitus, metallic taste, or agitation before seizures; recognize the progression, not just the endpoint. Air embolism is suggested by sudden dyspnea, chest pain, and oxygen desaturation during catheter manipulation.
Traps
Questions often test which finding is expected versus reportable. Mild pain at a new puncture is expected; expanding hematoma, pulselessness, or new paresthesia is not. Another trap is attributing hypotension only to sedation when bleeding is the cause - always assess the access site. Do not accept a single normal vital sign as reassurance when trend data show deterioration.
Rule of thumb
Compare every post-procedure finding against your own documented baseline, and treat any new distal neurovascular deficit as an access complication until proven otherwise.
Worked example
A patient becomes diaphoretic and nauseated during cannulation with a heart rate of 52 and BP 88/54. The correct action is to stop the procedure, lay the patient supine with legs elevated, and reassess - a vasovagal response - rather than to increase sedation or continue and monitor.