2.2 History, Allergies, Medications & Team Communication
Key Takeaways
- Metformin is held or continued around iodinated contrast per protocol because the danger is lactic acidosis if contrast-induced kidney injury develops, especially when eGFR is reduced.
- Shellfish allergy is not a true iodine cross-reaction; the history that changes the case is a prior iodinated-contrast reaction, plus latex and heparin-induced thrombocytopenia.
- Warfarin, DOACs, and heparin, and antiplatelets such as aspirin, clopidogrel, ticagrelor, and prasugrel, must be named with last dose because they change access, closure, and bleeding risk.
- Prior CABG requires graft anatomy from the operative report; prior stents, pacemaker/ICD, CKD, and pregnancy each alter projections, devices, contrast strategy, or whether fluoroscopy proceeds.
- The CI technologist announces rising ST segments, ACT, and contrast volume promptly in closed-loop form without waiting for a convenient pause that delays the operator.
History, Allergies, Medications, and Team Communication
Before the first needle, the CI technologist is a historian. Outline leaves 1.B.1 Patient History (clinical notes: medications, allergies; prior imaging) and 1.B.2 Interprofessional Communication (patient care team, physician) sit together because a history that stays in the chart instead of reaching the operator is not a history — it is a delayed complication.
Clinical Notes: What You Must Pull
Start with the indication and the procedure actually scheduled. Then read medications, allergies, and prior imaging. Do this in holding, not after the drape is up. The table below is the must-ask list; every row changes equipment, drugs, or whether the case proceeds.
| Must-ask history item | Why it changes the case |
|---|---|
| Metformin (and other biguanides) | Iodinated contrast plus acute kidney injury can precipitate metformin-associated lactic acidosis. Hold or continue per facility/physician protocol; concern rises when estimated glomerular filtration rate (eGFR) is reduced. Restart only after renal function is reassessed as ordered. |
| Warfarin, DOACs, heparin | Last dose and indication (atrial fibrillation, mechanical valve, venous thrombus) drive whether elective arterial access is safe, whether reversal is planned, and how you close. Intra-case unfractionated heparin is still expected for PCI — that is not the same as a home DOAC taken this morning. |
| Aspirin, clopidogrel, ticagrelor, prasugrel | Dual antiplatelet therapy (DAPT) after stenting depends on a load the patient can actually receive. Aspirin allergy, a missed P2Y12 load, or prasugrel in a patient with prior stroke changes the pharmacology plan. |
| Iodinated contrast / iodine / shellfish | Shellfish allergy is not a true iodine cross-reaction (the usual shellfish antigen is tropomyosin, not iodine). The history that matters is a prior iodinated-contrast reaction — hives, bronchospasm, anaphylaxis — and its severity. Still flag shellfish, clarify the actual reaction, and notify the physician; do not cancel solely on shrimp. |
| Latex | Swap to latex-free gloves, tourniquets, and drapes before opening the table. |
| Heparin-induced thrombocytopenia (HIT) | Unfractionated heparin and low-molecular-weight heparin are contraindicated. The operator needs an alternative (commonly bivalirudin or argatroban) before any heparinized flush hits the sheath. A buried HIT note is a classic preventable disaster. |
| Chronic kidney disease (CKD) | Baseline creatinine/eGFR stratifies contrast volume, hydration, and whether to stage a complex PCI. Normal labs last year is not a current screen. |
| Prior coronary artery bypass grafting (CABG) | You need graft anatomy from the operative report: left internal mammary artery (LIMA) to left anterior descending, saphenous vein grafts, radial-artery grafts, and any known occlusions. Blindly cannulating grafts without the map wastes contrast and time. |
| Prior stents | Location, date, and drug-eluting versus bare-metal status change projections, intravascular imaging, and whether the patient should already be on DAPT. |
| Pacemaker / ICD | Generator laterality affects left-sided access and clavicular projections; magnet and electrocautery plans matter in hybrid cases. Do not delay a STEMI for a full interrogation, but do know the device is there. |
| Pregnancy (or possibility) | Fluoroscopy and contrast both require a documented screen in anyone who could be pregnant. Positive or unknown status is a physician conversation before the pedal. |
Prior Imaging: Do Not Repeat Blindly
Old cath films and reports show dominance, chronic occlusions, stent landmarks, and which catheters worked. Coronary CT angiography can identify anomalous origins and calcium that change the first catheter choice. Echocardiographic ejection fraction (EF) warns you about left-ventricular filling pressure, ventriculography volume, and whether the patient will tolerate a long case. Nuclear perfusion maps a culprit territory in a non-STEMI and supports culprit-only versus more complete revascularization discussions. The CI technologist's job is not to interpret every study as a cardiologist; it is to make sure the relevant study is in the room and that a missing CABG operative report is announced before groin prep.
Interprofessional Communication: Patient-Care Team and Physician
History is useless if it stays in your head. The patient care team (holding RN, circulating RN, anesthesia or sedation provider, and CI technologist) and the physician must hear the same five sentences: identity, allergies that change drugs or gloves, last anticoagulant and antiplatelet doses, renal function, and implants or grafts.
Closed-loop again: HIT documented in 2019, no heparin on the table — physician repeats — correct, bivalirudin available. Creatinine 1.9, eGFR 32, last metformin last night — hold metformin, limit contrast, hydrate.
Say the finding, wait for the repeat, confirm. Do not bury HIT inside a five-minute medication monologue while the operator is tying a gown.
Communicating Critical Findings Without Delaying the Operator
During the case the CI technologist watches three streams the operator may not: the electrocardiogram (ECG) ST trend, the ACT analyzer, and the contrast tally.
- Rising ST segments or a new bundle-branch block after a wiring attempt: say it immediately, with the lead group and the blood pressure. Do not wait until the next cine run so you do not distract. Distraction is a delayed balloon.
- ACT: after a heparin bolus, read the number out loud as soon as it posts. An ACT that is still low is a thrombus risk; an unexpectedly high ACT is a bleeding risk if a closure device is planned. Repeat the number; do not editorialize for three sentences.
- Contrast volume: announce at planned checkpoints (for example every 50–100 mL, or when approaching the stated ceiling for a CKD patient). Offer the current total, not a lecture on nephropathy, while the operator is in a coronary.
The skill is short, timed, specific. One clause, a number, a closed loop. Then return to the table. That is how you communicate without becoming the delay.
A Worked History: Two Different Mornings
Elective radial diagnostic. A 71-year-old takes metformin, has eGFR 44, takes clopidogrel for a prior stent, and reports a shellfish allergy that was actually vomiting after shrimp. You clarify no prior contrast reaction, flag metformin hold per protocol, confirm the P2Y12 agent in case ad hoc PCI occurs, and pull last year's cath disc so the operator is not discovering a chronic right-coronary occlusion in real time.
STEMI with prior CABG. A 64-year-old has a 2014 bypass, an ICD, and warfarin for a mechanical mitral valve. You do not have twenty minutes, but you still shout HIT status, last international normalized ratio (INR) if known, ICD laterality, and that the operative report is — or is not — in the folder. Missing LIMA anatomy is worth a 15-second delay; missing it for the entire case is not faster, it is blind.
Traps. Treating iodine allergy and shellfish allergy as interchangeable absolute contraindications. Assuming the patient who takes a blood thinner is on aspirin when the bottle is apixaban. Discovering HIT when the first heparinized flush is already in the sheath. Reading an old echo EF of 55% and ignoring yesterday's report of 25% before a planned ventriculogram.
A patient reports a shellfish allergy on the holding questionnaire and has never received iodinated contrast. What should the CI technologist do?
A patient takes metformin 1000 mg twice daily and has an eGFR of 42 mL/min/1.73 m² before elective diagnostic catheterization with iodinated contrast. The BEST preprocedure plan is to:
During PCI the ACT prints at 165 seconds after a heparin bolus and ST segments are rising. How should the CI technologist communicate these findings?