2.5 Lines, Tubes, and Drains in Critical Care
Key Takeaways
- Central venous catheters, arterial lines, PA catheters, chest tubes, surgical drains, and feeding tubes each have specific pharmacotherapy implications (anticoagulation, infusion compatibility, drug-drug adsorption, and infection risk).
- Central line-associated bloodstream infections (CLABSI) are a National Patient Safety Goal; antimicrobial-impregnated catheters, chlorhexidine dressings, and prompt removal reduce risk.
- Drug-catheter adsorption (e.g., nitroglycerin, insulin, furosemide) and infusion line compatibility affect dose delivery and require dedicated lumen assignment in multi-lumen CVCs.
- Removal of indwelling devices requires balancing bleeding risk from required anticoagulation (ECMO, CRRT, LVAD) versus thrombosis risk from chronic and acute indications.
Lines, Tubes, and Drains in Critical Care
The BCCCP Examination Content Outline (1B5) covers lines, tubes, and drains as part of medical therapies and devices. The pharmacist's role centers on anticoagulation management, antimicrobial stewardship for catheter-related infection, infusion compatibility, and drug delivery through altered anatomy.
Vascular Access Device Overview
| Device | Indication | Pharmacotherapy Implication |
|---|---|---|
| Peripheral IV | Short-term access, stable meds | Vesicant infusions (vasopressors, chemo) require central access |
| Central venous catheter (CVC, multi-lumen) | Vasopressors, TPN, long-term access | Dedicate a lumen to TPN; drug-lumen adsorption (insulin, furosemide) |
| Antimicrobial-impregnated CVC (chlorhexidine/silver sulfadiazine, minocycline/rifampin) | High CLABSI risk | Reduces CLABSI; do not substitute for insertion bundle |
| Tunneled CVC (Hickman, Broviac) | Long-term chemotherapy, transplant | Lower CLABSI vs. non-tunneled; antimicrobial lock prophylaxis |
| PICC | Intermediate-term access | Vesicant and TPN compatible; thrombosis risk |
| Implantable port | Oncology, long-term intermittent access | Lowest CLABSI; accessed with Huber needle |
| Arterial line | Continuous BP monitoring, ABG | Heparinized or saline flush; risk of retrograde embolism |
| Pulmonary artery catheter | Hemodynamic profiling in shock | Heparin flush; risk of PA rupture, arrhythmia |
| ECMO cannulae | Cardiopulmonary support | Systemic anticoagulation (heparin/bivalirudin); drug sequestration in circuit |
| CRRT catheter | Renal replacement therapy | Anticoagulation (citrate, heparin); catheter function affects clearance |
Other Tubes and Drains
- Endotracheal tube: IV access needed; inhaled medications (albuterol, prostacyclin) delivered via ventilator circuit; ensure adequate sedation.
- Tracheostomy: reduces ventilator days; consider swallowing dysfunction and aspiration risk when initiating oral medications.
- Nasogastric/orogastric tube: medication administration route; verify tube placement; some drugs require intact stomach (e.g., ketoconazole, levothyroxine separation).
- Post-pyloric (NJ, Dobhoff) feeding tube: preferred for gastric intolerance or reflux; medication absorption may differ.
- Chest tube (tube thoracostomy): pleural drainage; consider chest tube output when dosing renally cleared drugs lost in third spacing.
- Surgical drains (JP, hemovac): output affects fluid balance and drug dosing volume.
- Urinary catheter: UTI prophylaxis not recommended; monitor for catheter-associated UTI (CAUTI).
- Ventriculostomy (EVD): intracranial pressure monitoring; antimicrobial-impregnated catheters reduce EVD infection; antibiotic prophylaxis at insertion only.
CLABSI Prevention and Antimicrobial Lock Therapy
The Society for Healthcare Epidemiology of America (SHEA)/IDSA/APIC strategies:
- Hand hygiene prior to access
- Maximal sterile barrier precautions at insertion
- Chlorhexidine skin antisepsis (>2%)
- Optimal site selection (subclavian preferred over femoral for non-tunneled CVC)
- Daily review of line necessity with prompt removal
- Antimicrobial-impregnated catheters for high-risk patients
- Chlorhexidine-impregnated dressings
- Antimicrobial lock therapy for long-term catheters (ethanol 70%, taurolidine, citrate, vancomycin/heparin for high-risk)
Infusion Compatibility and Drug-Catheter Adsorption
Drug adsorption: nitroglycerin, insulin, diazepam, furosemide, amiodarone adsorb to PVC tubing; use non-PVC lines or syringe pumps for sensitive drugs.
Lumen dedication: TPN requires a dedicated lumen; vasopressors may share a lumen; check compatibility charts before Y-site administration.
Alteplase lock: used to restore catheter patency in occluded CVCs; 2 mg dwell for 2 hours.
Anticoagulation Considerations by Device
| Device | Anticoagulation | Monitoring |
|---|---|---|
| Arterial line | Heparinized saline or saline-only flush | None routine |
| PA catheter | Heparinized saline flush | None routine |
| CRRT | Regional citrate (preferred unless citrate toxicity) or systemic heparin | Post-filter iCa, ACT/aPTT |
| ECMO | Systemic heparin (or bivalirudin in HIT) | ACT 180-220 or anti-Xa 0.3-0.7 IU/mL |
| LVAD | Aspirin + warfarin (INR 2-3) | INR; avoid dual antiplatelet unless indication |
Drug Delivery Through Altered Anatomy
Tubes and drains change how drugs reach the patient. The pharmacist must verify route compatibility on every order.
- Nasogastric/orogastric route: some drugs require an acidic stomach (ketoconazole, itraconazole, levothyroxine, digoxin) and should not be crushed or given with continuous feeds; hold feeds 30 minutes before and after.
- Post-pyloric (NJ, Dobhoff) route: avoids stomach, so acid-dependent absorption fails; enteric-coated and extended-release products should not be crushed and may not work post-pylorically.
- Do-not-crush list: extended-release, enteric-coated, cytotoxic, hormone, and sustained-release products; crushing causes dose dumping, toxicity, or loss of efficacy.
- Rectal route: useful when NPO or upper GI bleed, but absorption unreliable in diarrhea or low cardiac output.
- Sublingual/buccal route: preferred for nitroglycerin and lorazepam in shock when IV access is delayed.
- Inhaled route via ventilator circuit: albuterol, ipratropium, fluticasone, inhaled nitric oxide, nebulized N-acetylcysteine, and prostacyclin require a vibrating mesh nebulizer placed in the inspiratory limb; drug delivery drops with high humidity and long circuits.
Device Removal and Bleeding/Thrombosis Balance
Removing a device is a pharmacotherapy decision. The pharmacist must weigh thrombosis risk against bleeding risk and time removal to the anticoagulation cycle.
- CVC removal: stop any bolus heparin for 1-2 hours; INR <1.8, platelets >50,000.
- EVD/ICP monitor removal: reverse coagulopathy; INR <1.4 and platelets >100,000 per neurocritical care guidance.
- Chest tube removal: may remove on therapeutic anticoagulation if bleeding is controlled.
- ECMO decannulation: high-risk bleeding event; coordinate with surgery and perfusion; pause anticoagulation per protocol.
- CRRT catheter removal: remove after stopping citrate/heparin infusion.
Clinical Scenario
A patient on ECMO for ARDS develops catheter-related bloodstream infection. Vancomycin and piperacillin-tazobactam are started. How does the ECMO circuit affect drug delivery, and what monitoring is required?
Answer: The ECMO circuit sequestrates lipophilic drugs (propofol, fentanyl, midazolam) and binds heparin; antibiotic dosing should target higher peaks because of increased Vd. Vancomycin and beta-lactams are less sequestered but require therapeutic drug monitoring with peak/trough or Bayesian dosing given augmented clearance and circuit adsorption. Anticoagulation (heparin or bivalirudin) is titrated to anti-Xa or ACT per institutional protocol. Blood cultures from a peripheral site, not the ECMO circuit, drive de-escalation.
Which medication is most likely to adsorb to PVC tubing and require a non-PVC infusion set or syringe pump?
Which strategy is most effective at reducing central line-associated bloodstream infections (CLABSI) in long-term tunneled catheters?