1. Airway Management and Mechanical Ventilation

Securing the airway and ensuring adequate gas exchange are early priorities in patients with depressed mental status, compromised respiratory drive, or toxin-induced lung injury.

Indications for Intubation

• Respiratory depression: Respiratory rate <8/min or PaCO₂ >50 mm Hg
• Loss of airway reflexes: Glasgow Coma Scale (GCS) ≤8
• Severe hypoxemia: PaO₂/FiO₂ ratio <150

Ventilator Strategy

• Initial Settings: Use Assist-Control (AC) mode for apneic or hypoventilating patients. Target a tidal volume of 4–8 mL/kg of predicted body weight and maintain plateau pressure ≤30 cm H₂O to minimize lung injury.
• Oxygenation & PEEP: Titrate PEEP to achieve an SpO₂ of 88–95%, while weaning FiO₂ to ≤60% within 48 hours to mitigate oxygen toxicity.
• Weaning: Perform a daily spontaneous breathing trial (SBT) using a T-piece or low-level pressure support. Success is indicated by a Rapid Shallow Breathing Index (RSBI) <105 breaths/min/L, adequate oxygenation on minimal support, and hemodynamic stability.

2. Hemodynamic Support

Hypotension from vasodilation or myocardial depression demands tailored fluid and vasoactive regimens. High-dose insulin euglycemia (HIE) is a key therapy reserved for refractory calcium channel blocker or beta-blocker toxicity.

Fluid and Vasoactive Therapy

Initial management involves judicious fluid resuscitation with balanced crystalloids (e.g., lactated Ringer’s) in 10–20 mL/kg boluses, assessing responsiveness with dynamic measures like passive leg raise. If hypotension persists, vasoactive agents are required.

High-Dose Insulin Euglycemia (HIE) Therapy

Indicated for refractory shock from calcium channel or beta-blocker overdose, HIE therapy shifts myocardial metabolism to favor carbohydrate utilization, thereby enhancing contractility.

3. Prevention of ICU-Related Complications

Prophylactic care bundles are crucial to reduce morbidity from thrombosis, stress ulcers, glycemic extremes, and infections in critically ill toxicology patients.

• VTE Prophylaxis: Use low-molecular-weight heparin (e.g., enoxaparin 40 mg SC daily) or unfractionated heparin. Employ intermittent pneumatic compression devices if anticoagulation is contraindicated.
• Stress Ulcer Prophylaxis: Administer a proton pump inhibitor (PPI) or H₂-receptor antagonist (H₂RA) to patients on mechanical ventilation for >48 hours or those with coagulopathy.
• Glycemic Control: Use an insulin infusion to target a blood glucose range of 140–180 mg/dL. Avoid tight control (<140 mg/dL) to minimize the risk of iatrogenic hypoglycemia.
• Infection Prevention: Adhere to central line bundles, practice strict hand hygiene, and promote antimicrobial stewardship. Early removal of invasive devices is paramount.

4. Management of Iatrogenic Complications

Vigilance for and prompt treatment of delirium, hypotension, and arrhythmias are essential to minimize harm from necessary supportive therapies.

• Delirium: Screen with the CAM-ICU at least once per shift. Prioritize non-pharmacologic interventions (reorientation, sleep promotion, early mobilization). Reserve low-dose antipsychotics for refractory agitation and avoid benzodiazepines except in withdrawal syndromes.
• Hypotension: If sedation is a contributing factor, titrate sedatives like propofol or midazolam downward. Consider a fluid challenge (250–500 mL crystalloid) if the patient is preload responsive. Adjust vasopressors gradually to prevent abrupt changes in blood pressure.
• Arrhythmias: Avoid agents known to be pro-arrhythmic in specific toxidromes (e.g., procainamide in TCA overdose). Use amiodarone or lidocaine for refractory ventricular arrhythmias. Diligently monitor and correct electrolyte imbalances (especially K⁺ and Mg²⁺) and the QT interval.

5. Multidisciplinary Goals-of-Care Conversations

Early, structured discussions involving the patient or their surrogate are essential to align treatment intensity with prognosis and personal values, thereby reducing family distress and inappropriate resource utilization.

Framework for Discussion

• Timing: Initiate conversations when a patient experiences refractory multi-organ failure, requires extracorporeal support, or has a prolonged need for ventilation (>7 days). Routinely re-evaluate goals after 48–72 hours of high-intensity support.
• Team: Involve critical care physicians, toxicologists, pharmacists, nursing staff, and social workers. For intentional ingestions, psychiatry and palliative care are invaluable partners.
• Content: Clearly communicate the likelihood of meaningful recovery based on organ function and toxin kinetics. Discuss the burden and reversibility of proposed interventions in the context of the patient’s or surrogate’s stated values and advance directives.
• Documentation: Meticulously record specific goals of care, any limitations on therapy (e.g., DNI/DNR), and scheduled intervals for re-evaluation to ensure clear communication across all shifts and disciplines.