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2025 PACUPrep BCCCP Preparatory Course

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  1. Pulmonary

    ARDS
    4 Topics
    |
    1 Quiz
  2. Asthma Exacerbation
    4 Topics
    |
    1 Quiz
  3. COPD Exacerbation
    4 Topics
    |
    1 Quiz
  4. Cystic Fibrosis
    6 Topics
    |
    1 Quiz
  5. Drug-Induced Pulmonary Diseases
    3 Topics
    |
    1 Quiz
  6. Mechanical Ventilation Pharmacotherapy
    5 Topics
    |
    1 Quiz
  7. Pleural Disorders
    5 Topics
    |
    1 Quiz
  8. Pulmonary Hypertension (Acute and Chronic severe pulmonary hypertension)
    5 Topics
    |
    1 Quiz
  9. Cardiology
    Acute Coronary Syndromes
    6 Topics
    |
    1 Quiz
  10. Atrial Fibrillation and Flutter
    6 Topics
    |
    1 Quiz
  11. Cardiogenic Shock
    4 Topics
    |
    1 Quiz
  12. Heart Failure
    7 Topics
    |
    1 Quiz
  13. Hypertensive Crises
    5 Topics
    |
    1 Quiz
  14. Ventricular Arrhythmias and Sudden Cardiac Death Prevention
    5 Topics
    |
    1 Quiz
  15. NEPHROLOGY
    Acute Kidney Injury (AKI)
    5 Topics
    |
    1 Quiz
  16. Contrast‐Induced Nephropathy
    5 Topics
    |
    1 Quiz
  17. Drug‐Induced Kidney Diseases
    5 Topics
    |
    1 Quiz
  18. Rhabdomyolysis
    5 Topics
    |
    1 Quiz
  19. Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
    5 Topics
    |
    1 Quiz
  20. Renal Replacement Therapies (RRT)
    5 Topics
    |
    1 Quiz
  21. Neurology
    Status Epilepticus
    5 Topics
    |
    1 Quiz
  22. Acute Ischemic Stroke
    5 Topics
    |
    1 Quiz
  23. Subarachnoid Hemorrhage
    5 Topics
    |
    1 Quiz
  24. Spontaneous Intracerebral Hemorrhage
    5 Topics
    |
    1 Quiz
  25. Neuromonitoring Techniques
    5 Topics
    |
    1 Quiz
  26. Gastroenterology
    Acute Upper Gastrointestinal Bleeding
    5 Topics
    |
    1 Quiz
  27. Acute Lower Gastrointestinal Bleeding
    5 Topics
    |
    1 Quiz
  28. Acute Pancreatitis
    5 Topics
    |
    1 Quiz
  29. Enterocutaneous and Enteroatmospheric Fistulas
    5 Topics
    |
    1 Quiz
  30. Ileus and Acute Intestinal Pseudo-obstruction
    5 Topics
    |
    1 Quiz
  31. Abdominal Compartment Syndrome
    5 Topics
    |
    1 Quiz
  32. Hepatology
    Acute Liver Failure
    5 Topics
    |
    1 Quiz
  33. Portal Hypertension & Variceal Hemorrhage
    5 Topics
    |
    1 Quiz
  34. Hepatic Encephalopathy
    5 Topics
    |
    1 Quiz
  35. Ascites & Spontaneous Bacterial Peritonitis
    5 Topics
    |
    1 Quiz
  36. Hepatorenal Syndrome
    5 Topics
    |
    1 Quiz
  37. Drug-Induced Liver Injury
    5 Topics
    |
    1 Quiz
  38. Dermatology
    Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis
    5 Topics
    |
    1 Quiz
  39. Erythema multiforme
    5 Topics
    |
    1 Quiz
  40. Drug Reaction (or Rash) with Eosinophilia and Systemic Symptoms (DRESS)
    5 Topics
    |
    1 Quiz
  41. Immunology
    Transplant Immunology & Acute Rejection
    5 Topics
    |
    1 Quiz
  42. Solid Organ & Hematopoietic Transplant Pharmacotherapy
    5 Topics
    |
    1 Quiz
  43. Graft-Versus-Host Disease (GVHD)
    5 Topics
    |
    1 Quiz
  44. Hypersensitivity Reactions & Desensitization
    5 Topics
    |
    1 Quiz
  45. Biologic Immunotherapies & Cytokine Release Syndrome
    5 Topics
    |
    1 Quiz
  46. Endocrinology
    Relative Adrenal Insufficiency and Stress-Dose Steroid Therapy
    5 Topics
    |
    1 Quiz
  47. Hyperglycemic Crisis (DKA & HHS)
    5 Topics
    |
    1 Quiz
  48. Glycemic Control in the ICU
    5 Topics
    |
    1 Quiz
  49. Thyroid Emergencies: Thyroid Storm & Myxedema Coma
    5 Topics
    |
    1 Quiz
  50. Hematology
    Acute Venous Thromboembolism
    5 Topics
    |
    1 Quiz
  51. Drug-Induced Thrombocytopenia
    5 Topics
    |
    1 Quiz
  52. Anemia of Critical Illness
    5 Topics
    |
    1 Quiz
  53. Drug-Induced Hematologic Disorders
    5 Topics
    |
    1 Quiz
  54. Sickle Cell Crisis in the ICU
    5 Topics
    |
    1 Quiz
  55. Methemoglobinemia & Dyshemoglobinemias
    5 Topics
    |
    1 Quiz
  56. Toxicology
    Toxidrome Recognition and Initial Management
    5 Topics
    |
    1 Quiz
  57. Management of Acute Overdoses – Non-Cardiovascular Agents
    5 Topics
    |
    1 Quiz
  58. Management of Acute Overdoses – Cardiovascular Agents
    5 Topics
    |
    1 Quiz
  59. Toxic Alcohols and Small-Molecule Poisons
    5 Topics
    |
    1 Quiz
  60. Antidotes and Gastrointestinal Decontamination
    5 Topics
    |
    1 Quiz
  61. Extracorporeal Removal Techniques
    5 Topics
    |
    1 Quiz
  62. Withdrawal Syndromes in the ICU
    5 Topics
    |
    1 Quiz
  63. Infectious Diseases
    Sepsis and Septic Shock
    5 Topics
    |
    1 Quiz
  64. Pneumonia (CAP, HAP, VAP)
    5 Topics
    |
    1 Quiz
  65. Endocarditis
    5 Topics
    |
    1 Quiz
  66. CNS Infections
    5 Topics
    |
    1 Quiz
  67. Complicated Intra-abdominal Infections
    5 Topics
    |
    1 Quiz
  68. Antibiotic Stewardship & PK/PD
    5 Topics
    |
    1 Quiz
  69. Clostridioides difficile Infection
    5 Topics
    |
    1 Quiz
  70. Febrile Neutropenia & Immunocompromised Hosts
    5 Topics
    |
    1 Quiz
  71. Skin & Soft-Tissue Infections / Acute Osteomyelitis
    5 Topics
    |
    1 Quiz
  72. Urinary Tract and Catheter-related Infections
    5 Topics
    |
    1 Quiz
  73. Pandemic & Emerging Viral Infections
    5 Topics
    |
    1 Quiz
  74. Supportive Care (Pain, Agitation, Delirium, Immobility, Sleep)
    Pain Assessment and Analgesic Management
    5 Topics
    |
    1 Quiz
  75. Sedation and Agitation Management
    5 Topics
    |
    1 Quiz
  76. Delirium Prevention and Treatment
    5 Topics
    |
    1 Quiz
  77. Sleep Disturbance Management
    5 Topics
    |
    1 Quiz
  78. Immobility and Early Mobilization
    5 Topics
    |
    1 Quiz
  79. Oncologic Emergencies
    5 Topics
    |
    1 Quiz
  80. End-of-Life Care & Palliative Care
    Goals of Care & Advance Care Planning
    5 Topics
    |
    1 Quiz
  81. Pain Management & Opioid Therapy
    5 Topics
    |
    1 Quiz
  82. Dyspnea & Respiratory Symptom Management
    5 Topics
    |
    1 Quiz
  83. Sedation & Palliative Sedation
    5 Topics
    |
    1 Quiz
  84. Delirium Agitation & Anxiety
    5 Topics
    |
    1 Quiz
  85. Nausea, Vomiting & Gastrointestinal Symptoms
    5 Topics
    |
    1 Quiz
  86. Management of Secretions (Death Rattle)
    5 Topics
    |
    1 Quiz
  87. Fluids, Electrolytes, and Nutrition Management
    Intravenous Fluid Therapy and Resuscitation
    5 Topics
    |
    1 Quiz
  88. Acid–Base Disorders
    5 Topics
    |
    1 Quiz
  89. Sodium Homeostasis and Dysnatremias
    5 Topics
    |
    1 Quiz
  90. Potassium Disorders
    5 Topics
    |
    1 Quiz
  91. Calcium and Magnesium Abnormalities
    5 Topics
    |
    1 Quiz
  92. Phosphate and Trace Electrolyte Management
    5 Topics
    |
    1 Quiz
  93. Enteral Nutrition Support
    5 Topics
    |
    1 Quiz
  94. Parenteral Nutrition Support
    5 Topics
    |
    1 Quiz
  95. Refeeding Syndrome and Specialized Nutrition
    5 Topics
    |
    1 Quiz
  96. Trauma and Burns
    Initial Resuscitation and Fluid Management in Trauma
    5 Topics
    |
    1 Quiz
  97. Hemorrhagic Shock, Massive Transfusion, and Trauma‐Induced Coagulopathy
    5 Topics
    |
    1 Quiz
  98. Burns Pharmacotherapy
    5 Topics
    |
    1 Quiz
  99. Burn Wound Care
    5 Topics
    |
    1 Quiz
  100. Open Fracture Antibiotics
    5 Topics
    |
    1 Quiz

Participants 432

  • Allison Clemens
  • April
  • ababaabhay
  • achoi2392
  • adhoward1
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Lesson 30, Topic 3
In Progress

Pharmacologic and Supportive Management of Ileus and Acute Intestinal Pseudo-Obstruction

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Escalating Pharmacotherapy for Ileus and Acute Colonic Pseudo-Obstruction

Escalating Pharmacotherapy for Ileus and Acute Colonic Pseudo-Obstruction

Objectives Icon A checkmark inside a circle, symbolizing achieved goals.

Learning Objective

Design an evidence-based, escalating pharmacotherapy plan for a critically ill patient with ileus and acute colonic pseudo-obstruction.

1. Stepwise Pharmacotherapy Algorithm

A structured escalation from conservative support to targeted promotility therapy minimizes complications and the need for invasive decompression.

Initial Assessment (Suspected Ileus/ACPO)

(Exam, Labs, Contrast CT)

Exclude Mechanical Obstruction/Ischemia?

Yes

Surgical Consult/

Specific Tx
No (Functional)

Supportive Care

(Bowel Rest, NG, Electrolyte Correction)

Reassess (24-48h)

Persistent Cecal Diameter ≥10cm OR No Stool/Flatus?
No (Resolved)

Monitor

Yes (Persistent)

Pharmacotherapy (Neostigmine 1st line)

(Rule out contraindications)

Response to Medical Therapy?

Yes

Monitor

No / Red Flags

Escalate: Colonoscopic/Surgical Decompression

Figure 1: Stepwise Pharmacotherapy Algorithm for Ileus and ACPO. This algorithm outlines the diagnostic and therapeutic pathway, emphasizing initial supportive care, appropriate use of pharmacotherapy, and criteria for escalation to invasive procedures.
  • Exclude mechanical obstruction and ischemia via clinical exam, laboratory markers (lactate) and contrast-enhanced CT.
  • Initiate supportive care: bowel rest, nasogastric decompression, aggressive correction of hypokalemia, hypomagnesemia and hypocalcemia.
  • Reassess at 24–48 hours: persistent cecal diameter ≥10 cm or absence of stool/flatus despite correction of reversible factors indicates need for pharmacotherapy.
  • Choose promotility agents only after ruling out contraindications; escalate to colonoscopic or surgical decompression if medical therapy fails or if there are red-flag signs (perforation, worsening pain).
Pearl IconA shield with an exclamation mark. Key Pearls
  • Never administer promotility agents in suspected mechanical obstruction or ischemia.
  • Early electrolyte repletion is foundational and may restore motility without prokinetics.

2. Neostigmine as First-Line Agent

Neostigmine, a reversible acetylcholinesterase inhibitor, is the most effective medical therapy for acute colonic pseudo-obstruction (ACPO) after failed conservative measures.

Mechanism

Inhibits acetylcholinesterase → increased acetylcholine → enhanced colonic smooth muscle contraction.

Indication

ACPO without evidence of mechanical obstruction, perforation or ischemia; cecal diameter ≥10 cm.

Dosing

2 mg IV over 3–5 minutes; may repeat once after 3–6 hours if no response.

Monitoring

Continuous ECG/telemetry for bradycardia; heart rate and blood pressure every 5 minutes during and for 30–60 minutes post-dose; atropine (0.5–1 mg IV) or glycopyrrolate at bedside.

Adverse Effects

Bradycardia, hypotension, salivation, bronchospasm, abdominal cramping.

Contraindications

Mechanical obstruction, suspected ischemia/perforation, significant bradyarrhythmias, active bronchospasm.

Pearl IconA shield with an exclamation mark. Clinical Pearl

Glycopyrrolate may mitigate central cholinergic effects without blunting colonic response.

Controversy IconA chat bubble with a question mark. Controversy

Repeat neostigmine dosing versus immediate colonoscopic decompression after a single treatment failure remains debated; consider patient stability, resource availability and procedural risk.

3. Adjunctive Prokinetic Agents

Metoclopramide and erythromycin serve as secondary options for upper GI dysmotility or when neostigmine is contraindicated.

A. Metoclopramide

  • Mechanism: Dopamine D2 antagonist + 5-HT4 agonist → increased acetylcholine release in the enteric plexus.
  • Indications: Upper GI ileus; adjunct for mixed motility disorders.
  • Dosing: 10 mg IV every 6 hours.
  • Monitoring: QTc interval on ECG, extrapyramidal symptoms (dystonia, akathisia).
  • PK/PD: Hepatic metabolism, renal excretion; reduce dose if eGFR <40 mL/min/1.73 m² or in hepatic impairment.
  • Pitfalls: Limited colonic efficacy; risk of tardive dyskinesia with prolonged use.

B. Erythromycin

  • Mechanism: Motilin receptor agonist → stimulates migrating motor complexes.
  • Indications: Refractory upper GI dysmotility or select adjunctive use.
  • Dosing: 3 mg/kg IV every 8 hours, infused over 20–30 minutes to reduce GI discomfort and phlebitis.
  • Monitoring: QTc interval, liver function tests; antibiotic stewardship considerations.
  • PK/PD: Extensive hepatic metabolism (CYP3A4); numerous drug–drug interactions; reduce dose in hepatic insufficiency.
  • Pitfalls: Tachyphylaxis after several days; potential for antibiotic resistance.

Red-Flag Criteria for Avoidance:

  • New or worsening abdominal pain, fever, leukocytosis or peritoneal signs – discontinue promotility agents and evaluate for surgery.

4. Pharmacokinetic and Pharmacodynamic Considerations in Critical Illness

Critical illness alters volume of distribution, clearance and drug interactions, necessitating individualized dosing and monitoring.

  • Volume of distribution: Increased with fluid overload and capillary leak → may delay onset and lower peak concentrations of hydrophilic agents (e.g., neostigmine).
  • Clearance: Decreased in hepatic or renal dysfunction → prolongation of drug half-life; adjust dosing interval or dose.
  • Renal replacement therapy: Partially clears neostigmine; consider 50% dose reduction or extended interval in patients on CVVH.
  • Polypharmacy: Erythromycin’s CYP3A4 inhibition can elevate levels of other QT-prolonging drugs; metoclopramide may potentiate CNS depressants.
Key Point IconA lightbulb, symbolizing an important idea. Key Point

Partner with critical care pharmacy to adjust regimens in real time as organ function evolves.

5. Administration Routes and Delivery Devices

Proper route selection and compatibility checks optimize efficacy and safety of promotility therapies.

  • Neostigmine: IV slow bolus via central or well-functioning peripheral line; avoid co-infusion with alkaline solutions; dedicate a lumen and have resuscitation kit at bedside.
  • Metoclopramide/Erythromycin: IV bolus or infusion via syringe pump; use central line if available; flush lines before and after administration to prevent precipitation.
  • Compatibility: Administer separately from lipid emulsions and alkaline infusions; consult compatibility charts for co-administered ICU drugs.

6. Monitoring Therapeutic Efficacy and Toxicity

A combination of clinical, laboratory, imaging and cardiac surveillance ensures timely recognition of efficacy and adverse events.

  • Clinical: Passage of flatus/stool, reduction in abdominal distension, pain score improvement.
  • Laboratory: Electrolytes, lactate and organ perfusion markers to detect ischemia.
  • Cardiac: Continuous ECG during and for 30–60 minutes after neostigmine; monitor for bradyarrhythmias, AV block.
  • Imaging: Serial abdominal radiographs or CT to document colonic decompression and exclude complications.
  • Documentation: Record timing of response, vital sign changes and any need for atropine or escalation to procedural therapy.
Pearl IconA shield with an exclamation mark. Clinical Pearl

Most neostigmine-induced bradycardia occurs within minutes; vigilance in the first 10–15 minutes post-dose is critical.

7. Pharmacoeconomic Analysis

Neostigmine offers a low-cost, high-efficacy alternative to invasive decompression with favorable resource utilization.

  • Acquisition cost: Neostigmine is inexpensive relative to colonoscopy or surgery; metoclopramide and erythromycin carry moderate drug costs.
  • Monitoring cost: Minimal additional equipment beyond standard ICU telemetry and vital signs monitoring.
  • Resource utilization: Reduces ICU length of stay and need for endoscopic or surgical interventions.
  • Adverse event management: Low incidence when properly monitored; costs associated with side-effect reversal (atropine) are minimal.
Key Point IconA lightbulb, symbolizing an important idea. Key Point

From a cost-benefit perspective, neostigmine is first-line for ACPO after conservative management fails.

8. Clinical Decision Points and Case Scenarios

Tailor therapy based on hemodynamic stability, organ function and response to prior interventions.

  • Case 1: Hemodynamically unstable on vasopressors – defer neostigmine until MAP ≥65 mmHg; optimize fluids and electrolytes first.
  • Case 2: On continuous renal replacement therapy – reduce neostigmine dose to 1 mg IV or extend dosing interval; intensify cardiac monitoring.
  • Case 3: Failed two neostigmine doses – proceed to colonoscopic decompression with careful bowel preparation and surgical backup.
Pearl IconA shield with an exclamation mark. Clinical Pearl

Pharmacologic and procedural therapies are complementary; failure of one does not preclude safe transition to the other.

References

  1. Ponec RJ, Saunders MD, Kimmey MB. Neostigmine for the treatment of acute colonic pseudo-obstruction. N Engl J Med. 1999;341(3):137–141.
  2. Kamm MA. Intestinal pseudo-obstruction. Gut. 2000;47(Suppl IV):iv84.
  3. Catena F, De Simone B, Coccolini F, et al. Bowel obstruction: a narrative review for all physicians. World J Emerg Surg. 2019;14(1):20.
  4. Vanek VW, Al-Salti M. Acute pseudo-obstruction of the colon (Ogilvie’s syndrome): an analysis of 400 cases. Dis Colon Rectum. 1986;29(3):203–210.
  5. Cronnelly R, Stanski DR, Miller RD, et al. Renal function and the pharmacokinetics of neostigmine in anesthetized man. Anesthesiology. 1979;51(3):222–226.
  6. Child CS. Prevention of neostigmine-induced colonic activity: a comparison of atropine and glycopyrronium. Anaesthesia. 1984;38(10):1083–1085.
  7. Webb MD. Type I second-degree AV block after neostigmine administration in a child with renal failure. Anesthesia Progress. 1995;42(1):21–22.
  8. Rex DK. Colonoscopy and acute colonic pseudo-obstruction. Gastrointest Endosc Clin N Am. 1997;7(3):499–508.
  9. Hutchinson R, Griffiths C. Acute colonic pseudo-obstruction: a pharmacological approach. Ann R Coll Surg Engl. 1992;74(6):364–367.
  10. Turegano-Fuentes F, Muñoz-Jiménez F, Del Valle-Hernández E, et al. Early resolution of Ogilvie’s syndrome with intravenous neostigmine: a simple, effective treatment. Dis Colon Rectum. 1997;40(11):1353–1357.