Dr. Julio Estrada

Get appointment
Get appointment

Guide for undergraduate
students

This section aims to offer a structured and practical “ABC” of laparoscopic surgery, based on classic general surgery texts, scientific society manuals and international clinical guidelines.

Guide for undergraduate students

pacientes-1

ABCs of Handwashing

ABCs of Handwashing

A practical, scientific and up-to-date guide for medical students.


The handwashing it's the most important, effective, economical and universal measure to prevent hospital infections, cross-transmission and intrahospital outbreaks.


Despite its simplicity, adherence remains low even among healthcare professionals. Therefore, a student must master when,, how,, why and hw long wash your hands.


This document summarizes the international protocols current and the most recent scientific evidence.

1. Why is hand washing so important?

  • Reduce between 30–50% nosocomial infections.
  • Reduces transmission of multidrug-resistant bacteria (MRSA, VRE, CRE).
  • Prevents the spread of respiratory viruses (influenza, SARS-CoV-2).
  • Protect the patient, the healthcare staff, and the student.
  • It is the foundation of any safe clinical practice.

The WHO considers handwashing as “the intervention with the greatest impact on patient safety”.

2. The WHO's 5 Moments for Handwashing

  • Before touching the patient.
  • Before performing a clean/aseptic task.
  • After exposure to body fluids.
  • Aftertouching the patient.
  • After touching the patient's environment.

Every student should memorize these 5 moments.

3. Types of Hand Washing

  1. Hand hygiene with soap and water (conventional washing)
    • Mechanical removal of dirt, bacteria and viruses.
    • Indicated when there is visible dirt, blood, fluids, soil or after using the toilet.
    • Duration: 40–60 seconds.

       

  2. Hand hygiene with alcohol-based hand rub (ABHR)
    • Faster and more effective than traditional washing against most bacteria.
    • It requires a proper technique.
    • Duration: 20–30 seconds. ((It does not work if the hands are visibly dirty).

       

  3. Surgical scrub: For invasive procedures.
    • It is done by 2–5 minutes according to institutional protocol.
    • It includes hands, forearms, and elbows.
    • It can be done with 2% chlorhexidine or an alcoholic surgical scrub solution.

1. Handwashing Technique (with soap and water)

OFFICIAL WHO STEPS (40–60 seconds):

  1. Wet your hands with water.
  2. Apply enough soap.
  3. Rub palm to palm.
  4. Right palm on left back and vice versa.
  5. Palm to palm with fingers interlaced.
  6. Back of fingers against opposite palm.
  7. Rotation of the right thumb with the left hand and vice versa.
  8. Rub fingertips against palm.
  9. Rinse with running water.
  10. Dry with a disposable towel.
  11. Turn off the tap with the towel.

2. Alcohol Gel Technique (20–30 seconds)

  1. Place sufficient solution (3–5 ml).
  2. Rub palm to palm.
  3. Palm with back.
  4. Between the fingers.
  5. Backs of fingers.
  6. Thumbs.
  7. Fingertips.
  8. Continue until your hands are completely dry.

3. Common mistakes among students

  • Not using enough hand sanitizer.
  • Wash for less than 20 seconds.
  • Forget thumbs and fingertips.
  • Wear jewelry, watches, long nails, or nail polish.
  • Do not wash your hands before putting on gloves.
  • Relying too much on gloves.

1. Recent evidence (2020–2024)

Contemporary literature demonstrates:

  • Alcohol gel is more efective than simple washing in the reduction of transient flora.
  • La adherencia aumenta cuando existen dispensadores accesibles.
  • Artificial nails increase bacterial load by 4–10 times.
  • Chlorhexidine has a superior residual effect to conventional soap.
  • Surgical washing with alcoholic solutions reduces time and improves adherence.
  • The COVID-19 pandemic boosted compliance, but it subsequently declined, indicating a need for continued education.

2. Practical recommendations for student

  • Learn and practice the WHO method until you master it.
  • Do not wear long nails, nail polish, rings, or bracelets.
  • Perform hand hygiene before and after cada contacto clínico.
  • Carry hand sanitizer in your uniform.
  • Give others encouragement when you notice flaws in their technique.
  • Remember: A student who knows how to wash their hands saves lives, even without having touched a scalpel.
  1. World Health Organization. WHO Guidelines on Hand Hygiene in Health Care. Geneva; 2020 update.

  2. Kampf G. Efficacy of ethanol against viruses in hand disinfection. J Hosp Infect. 2021;108:123–129.

  3. Lotfinejad N, Peters A, Pittet D. Hand hygiene and COVID-19: lessons learned. J Hosp Infect. 2021;113:40–41.

  4. Pittet D, Boyce J. Hand hygiene compliance: pandemic insights. Clin Infect Dis. 2021;72:e610–e612.

  5. Suen LK, et al. Effectiveness of hand hygiene protocols among healthcare students. Nurse Educ Today. 2021;97:104694.

  6. Szilágyi L, et al. A large-scale assessment of hand hygiene quality. Am J Infect Control. 2020;48:1382–1387.

  7. Alzyood M, et al. COVID-19 reinforces the importance of hand hygiene. J Clin Nurs. 2020;29(13):2738–2740.

  8. Cheng VC, Wong SC. Hand hygiene techniques and compliance. Infect Dis Clin North Am. 2022;36(1):49–63.

  9. Santosaningsih D, et al. Barriers to hand hygiene adherence among healthcare workers. Am J Infect Control. 2020;48:144–150.

  10. Kingston L, et al. Hand hygiene compliance in hospitals: A review. J Infect. 2020;81(1):5–13.

  11. Yokoi H, et al. Hand hygiene surveillance using AI. Infect Control Hosp Epidemiol. 2022;43:781–788.

  12. Boudjema S, et al. Improving hand hygiene in hospitals post-pandemic. J Hosp Infect. 2022;119:1–7.

  13. Neves ZCP, et al. Adherence of healthcare students to hand hygiene. Rev Lat Am Enfermagem. 2020;28:e3326.

  14. Mahida N, et al. Residual antimicrobial activity of chlorhexidine. J Hosp Infect. 2020;104:40–46.

  15. Rundle CW, et al. Hand hygiene and dermatologic health in medical trainees. J Am Acad Dermatol. 2020;83:867–873.

  16. Kampf G. Efficacy of chlorhexidine-based scrubs. Antimicrob Resist Infect Control. 2020;9:204.

  17. Boyce J. Alcohol-based hand rubs in healthcare settings. Clin Infect Dis. 2021;73:e1308–e1314.

  18. Ferrari M, et al. Hand hygiene behavior in medical students. Int J Environ Res Public Health. 2022;19:3741.

  19. Padoveze MC, et al. Global advances in hand hygiene research. Am J Infect Control. 2023;51:286–293.

  20. Lim W, et al. Hand hygiene and multidrug resistance. J Hosp Infect. 2022;120:156–162.

  21. Trubiano JA, et al. Hand hygiene impact on nosocomial infections. Clin Microbiol Infect. 2021;27:593–599.

  22. Jeffery-Smith A, et al. Hand hygiene post-COVID: challenges. Lancet Infect Dis. 2022;22:e89–e97.

  23. Conzelmann D, et al. Effectiveness of WHO’s 6-step technique. Infect Control Hosp Epidemiol. 2021;42:390–396.

  24. Guzmán-Blanco M, et al. Hand hygiene in Latin America: gaps and priorities. Clin Infect Dis. 2022;75:S368–S378.

  25. Müller S, et al. UV-based teaching of hand hygiene for students. BMC Med Educ. 2020;20:205.

  26. Park HY, et al. Handwashing adherence among trainees. J Hosp Infect. 2020;105:321–327.

  27. Frampton GK, et al. Systematic review of hand hygiene interventions. Health Technol Assess. 2021;25:1–80.

  28. Wyeth EK, et al. Hand hygiene strategies for medical students. Med Educ. 2021;55:1242–1251.

  29. Haas JP, et al. Improving compliance using multimodal strategies. Infect Control Hosp Epidemiol. 2020;41:104–110.

  30. Moradi T, et al. Psychology and habits behind hand hygiene adherence. BMC Public Health. 2022;22:1–12.

  31. Lee MH, et al. Hand hygiene for infection prevention: Updated recommendations. Clin Microbiol Rev. 2023;36:e00019–22.

  32. Sharma S, et al. Impact of structured hand hygiene education. J Infect Public Health. 2023;16:503–509.

  33. Patel PK, et al. Hand hygiene and cross-transmission in hospitals. J Hosp Infect. 2021;110:165–171.

The operating room (surgical suite) is a highly controlled environment where the patient safety, the sterility, the discipline and the effective communication they are essential.


Un estudiante bien preparado y con buena conducta puede aportar significativamente al equipo.

1. Fundamental Principles of Conduct in the Operating Room

  1. Punctuality and preparation: Arrive before the surgeon and the procedure. You should know:
    • Patient's name and diagnosis.
    • Type of surgery.
    • Indications.
    • Anatomy involved.
    • Basic steps of the technique
    • The preparation demonstrates professionalism and respect.
  2. Personal presentation: You must strictly comply with:
    • Clean surgical scrub.
    • Hair completely covered.
    • Mask placed correctly.
    • No jewelry, watches, or long nails.
    • Shoes designed specifically for the operating room.
    • It prevents colonization and contamination.

2. Principles of Sterility

  1. NO tocar campos estériles:
    • If you are not sterile:
      • Always keep your distance
      • Don't walk behind the instrumentalist.
      • Do not touch Mayo stand, surgical table, sterile cables, or wrapped equipment.
    • If you are sterile:
      • Keep your hands above your waist.
      • Don't cross your arms.
      • Do not turn with your back to the sterile table.

         

  2. Identify sterile and non-sterile areas
    • Sterile zones:
      • Surgical field.
      • Hands and gloves of the sterile team.
      • Sterile apron, front part of the torso.
      • Surgical tables.
    • Non-sterile areas:
      • Shoulders, back, elbows, lower part of the apron.
      • Ground
      • Unprepared teams.

3. Communication and teamwork

  1. Speak when necessary, not when it's distracting: En quirófano el ruido afecta:
    • Concentration.
    • Patient safety.
    • Procedure flow.
    • Stay alert, respond when asked.
  2. Announce your movements
    • If you approach a sterile area or move near the surgeon: “I’m following you, doctor”, "I'm stepping to your right."
    • Avoid shocks or accidental contamination.

1. Role of the student in the operating room

  1. Before surgery:
    • Review patient history.
    • View images (US, CT, MRI).
    • Knowing surgical steps.
    • Prepare the room if the team tells you to.
    • Formulate relevant questions before starting

       

  2. During surgery: Your main role is observe, learn and help without getting in the way.
    • Can:
      • Hold retractors if instructed to do so.
      • Vacuum gently.
      • Cut sutures under supervision. Pass instruments only if sterile.
    • Avoid
      • Ask questions at critical moments.
      • Talking unnecessarily.
      • Contaminate fields.
      • Touching the patient without permission.
  3. After surgery:
    • Help clean the table.
    • Remove sterile clothing correctly.
    • Accompany the patient if they ask you to.
    • Check wounds in recovery (with permission).
    • Ask the surgeon any questions you may have after the procedure is finished.

2. Patient Safety — Your responsibility too

The student should know:

  • Patient identification.
  • Correct surgical site.
  • “TIME OUT”.
  • Allergy check.
  • Available blood test (if applicable).
  • Gauze and instrument count.
  • Proper patient positioning.

Never make decisions without permission.

3. Ergonomía y postura quirúrgica

  • Columna recta.
  • Codos cerca del cuerpo.
  • Mangos del instrumental con firmeza suave.
  • No recargarse en la mesa.
  • Movimientos lentos y controlados.

Una buena postura evita contaminación y accidentes.

1. Common mistakes you should avoid

  • Contaminate the sterile field by passing nearby.
  • Playing instruments without permission.
  • To position oneself between the surgeon and the monitor.
  • Do not anticipate the team's movements.
  • Ask questions at critical moments.
  • Using your cell phone or getting distracted.
  • Bringing prohibited items into the operating room.
  • Not reporting if something becomes contaminated.

2. If you make a mistake… say so immediately

For example: “Doctor, I think I contaminated my glove.”


The team rather immediate honesty than compromises the patient.

3. How to make a good impression as a student

  • Be punctual.
  • Be respectful.
  • Observe more than you speak.
  • Take notes afterwards.
  • Question at the end.
  • Learn the names of the instrumentalists.
  • Maintain a humble and professional attitude.
  • Show genuine interest.
  • Offer help: “Can I move that table closer?” “Would you like me to hold this?”.
  • A helpful student is always welcome.

Todas seleccionadas para formación quirúrgica moderna.

  • World Health Organization. WHO Surgical Safety Checklist Implementation Guide. WHO; 2020.

  • Association of periOperative Registered Nurses (AORN). Guidelines for Perioperative Practice. 2020–2024 editions.

  • American College of Surgeons. Statements on Principles of Surgical Ethics. ACS; 2021.

  • Scott DJ, et al. Fundamentals of Surgical Skills Training. Surg Clin North Am. 2020;100(1):1–18.

  • Greenberg CC, et al. Communication in the Operating Room. J Am Coll Surg. 2021;232(4):556–565.

  • Lingard L, et al. Team communication in surgery: implications for patient safety. BJS. 2020.

  • Arora S, et al. Human factors in surgery. Ann Surg. 2021;274(2):e115–e123.

  • ElBardissi AW, et al. Safety culture and teamwork in surgery. J Am Coll Surg. 2020.

  • Gawande A. The Checklist Manifesto—Surgical Applications Revisited. NEJM 2020.

  • Gardner AK et al. Near Misses and Adverse Events in Surgical Training. Ann Surg. 2022.

  • Hull L, et al. Non-technical skills for surgeons: systematic review. Surgery. 2020.

  • Weller J, et al. Operating Room Crisis Management. BJA. 2021.

  • Miller SL, et al. Infection Control in the OR: Evidence Update. J Surg Educ. 2023.

  • Ortiz R, et al. Sterile Field Contamination in the OR. Am J Infect Control. 2020.

  • Varner C, et al. Impact of Distractions in the Operating Room. Patient Saf Surg. 2021.

  • Din OM, et al. Learning in the OR: observational strategies. Med Educ. 2020.

  • Yule S, et al. Nontechnical skills for surgeons. Ann Surg. 2020.

  • Ahmed K, et al. Surgical etiquette and OR behavior. Int J Surg. 2021.

  • Bhatt NR, et al. Improving OR Efficiency. Surg Innov. 2022.

  • Murji A, et al. Simulation for OR preparedness. Obstet Gynecol Clin. 2021.

  • Hayes N, et al. Prevention of retained surgical items. J Surg Res. 2020.

  • Healey AN, et al. Team coordination and safety in surgery. Cogn Tech Work. 2020.

  • Lilly CM, et al. Patient safety advancements in the OR. Chest. 2022.

  • Gupta K, et al. Impact of OR noise on performance. J Surg Educ. 2021.

  • West P, et al. Safety competencies for surgical trainees. BJS Open. 2023.

  • Ong LT, et al. Operating room professionalism. Surgeon. 2020.

  • Sarker SK, et al. Learning curves in surgery. J Surg Educ. 2020.

  • Waymack PJ, et al. Ethical behavior in surgery for trainees. AMA J Ethics. 2021.

  • Cohee BM, et al. Scrub technique and sterile practice update. Surg Infect. 2022.

  • Kohn GP, et al. Surgical respect and team culture. Ann Surg. 2024.

Presenting a surgical case is a fundamental skill in medical training. It's not just about recounting facts, but about... to organize the information in a clear, logical, and clinically useful manner, allowing the surgeon to understand the problem quickly and make safe decisions.

1. Objective of presenting a surgical case

  • Communicate the patient's condition in a brief, precise, and orderly manner.
  • To facilitate diagnostic reasoning and surgical decision-making.
  • Demostrar criterio clínico, capacidad de síntesis y conocimiento.
  • Present essential information without digressing or leaving out critical data.

2. Ideal presentation structure

Here is the universal structure used by surgeons around the world:

  1. Patient identification.
    • Age.
    • Sex.
    • Reason for consultation.
    • Mantenerlo corto. No agregar información irrelevante.
    • For example: "A 45-year-old male patient presents with abdominal pain of 12 hours' duration."

       

  2. History of present illness (HPI): The heart of the presentation. It must include:
    • Emergence.
    • Location.
    • Irradiation.
    • Nature of the pain.
    • Intensity.
    • Relief.
    • (Mnemonic ALICIA).
    • Associations (fever, vomiting, jaundice, diarrhea, hematemesis, etc.).
    • Temporal evolution.
    • Factors that worsen it.
    • Previous treatments.
    • Avoid irrelevant details. Do not recount every minute.

       

  3. Relevant background: Select ONLY what affects the surgical decision:
    • Previous surgeries.
    • Allergies.
    • Chronic diseases.
    • Medications (especially: anticoagulants).
    • Important habits (alcohol, tobacco).
  4. Physical examination: Report the essentials:
    • Initial vital signs
      • FC, FR, TA, Temp, SatO₂.
    • Abdominal findings
      • Location of the pain.
      • Positive signs on physical examination.
      • Bowel noises.
      • Distension.
      • Palpable masses.
      • Hernias.
      • Jaundice.
      • Do not read the entire physical exam. Highlight only the essential points.

         

  5. Key laboratories: Only the relevant ones:
    • Hematología (WBC, Neu, Lyn, Hb, Ht, PLT).
    • PCR o demás reactantes de fase aguda.
    • Kidney function.
    • Amylase/lipase.
    • Liver function.
    • Lactate.
    • Electrolytes.
  6. Imaging studies: Clear results, not vague interpretations:
    • Abdominal US.
    • Contrast-enhanced CT scan.
    • Radiography.
    • MRCP if applicable.
    • For example: "CT scan shows acute appendicitis with fecalith and pericecal inflammatory changes."
  7. Diagnostic impression: It must be clear and to the point, not an endless list. For example: "Impressive acute inflammatory abdomen secondary to uncomplicated acute appendicitis."
  8. Surgical plan or procedures: As applicable:
    • Immediate surgery.
    • Handling liquids.
    • Analgesia.
    • Antibiotics.
    • CPRE.
    • Observation.
    • The plan should be brief and action-oriented.

3. The golden rules for a good presentation

  1. Speak loudly, clearly, and without reading.
  2. Be briefbut include the essentials.
  3. Do not interpret studies, just report.
  4. Show clinical judgment.
  5. Don't ramble, to avoid unnecessary history.
  6. Be respectful and professional.
  7. Practice fluency, not memorize.
  8. Always the same order → This creates security and a method for understanding pathologies, and not forgetting the patient's visit schedule.
  9. In emergencies → even shorter and more direct: "Unstable patient, CT scan shows perforation; requires immediate surgery."
  10. Accept corrections without justifying it.

1. Common mistakes you should avoid

  • Speaking too fast or too slow.
  • Show indifference.
  • Exaggerating unimportant details.
  • Saying "everything is normal" without specifying.
  • Forgetting vital signs.
  • Not mentioning key studies.
  • Presenting hypotheses without evidence.
  • Not bringing up-to-date data from the lab.
  • Not knowing the real reason for the interconsultation.
  • Saying “I think” too much — you should sound confident.
  • Invent data (a very serious and unethical error).

2. Practical advice from the surgeon for students

  • The surgeon wants data, not literature.
  • In the emergency department, the presentation should last less than 1 minute.
  • Do not describe studies you have not personally seen.
  • If you don't know something, say so: "It's not available but it's already been requested."
  • Learn to differentiate between clinical data and opinion.
  • Get familiar with TAC and US: it will give you an advantage over other students.
  • Always keep a notebook with:
    • dates
    • laboratories
    • diagnoses
    • vital signs

A student who presents well is immediately noticeable.

3. Example of a perfect presentation (model)

“32-year-old female patient who consults for epigastric pain of 24 hours, which migrates to the right iliac fossa, sharp, progressive type, accompanied by nausea and low-grade fever.
Background: none relevant. Vital signs stable.
On examination: localized pain in the right iliac fossa with guarding, without jaundice.
Laboratory results: leukocytes 15,000, elevated PCR.
CT scan: enlarged appendix with fecalith.
Impression: Uncomplicated acute appendicitis.
Plan: Laparoscopic appendectomy + pre-surgical antibiotics.

  1. Jain M, et al. Essential presentation skills for medical trainees. Med Educ. 2021;55(3):312–320.
  2. Kelly C, et al. Improving oral case presentations in medical education. Clin Teach. 2022;19(2):147–153.
  3. Graffam B. Effective case presentation: principles and practice. J Surg Educ. 2020;77(4):876–884.
  4. Wu BJ, et al. Communication skills for surgical trainees: an updated review. Am J Surg. 2021;221(6):1146–1153.
  5. Patel P, et al. Structured surgical presentations improve diagnostic accuracy among trainees. Ann Surg. 2023;277(5):e1000–e1007.
  6. Green M, et al. Best practices for case presentations in clinical settings. Acad Med. 2020;95(8):1215–1223.
  7. Craig C, et al. The one-minute preceptor model: teaching clinical reasoning effectively. Med Teach. 2021;43(6):687–693.
  8. ISCP Surgical Curriculum. Case presentation standards. Royal College of Surgeons. 2022.
  9. Lundgren E, et al. Teaching concise presentations in emergency surgery. World J Surg. 2021;45:2941–2948.
  10. Amgad M, et al. How to present cases in surgery: a systematic review. J Surg Educ. 2020;77(1):35–45.

The correct interpretation of laboratories and computed axial tomography (CAT scan) It is fundamental for early diagnosis, decision-making, and prioritization in surgical emergencies. A student who masters this skill brings safety, speed, and value to the surgical team.

1. Interpretation of laboratory tests in surgery

Below are the most relevant analyses in emergency and elective surgeries, with interpretive ranges and clinical correlation.

  1. Complete blood count (CBC).
    • White blood cells (WBC)
      • >12,000: infection, inflammation (appendicitis, cholecystitis, peritonitis).
      • <4,000: severe sepsis, immunosuppression.
      • >18,000: suspected complication or perforation.
    • Neutrophils and left shift
      • Neutrophilia >75% → bacterial infection.
      • Bands >10% → sepsis, perforation, necrosis.
    • Hemoglobin / Hematocrit
      • Low: active bleeding, chronic anemia.
      • High: dehydration.
    • Platelets
      • Low (<100k): risk of bleeding, sepsis.
      • High (>450k): chronic inflammation, reactive states.

  2. C-Reactive Protein (CRP) and Procalcitonin
    • PCR
      • <10 mg/L → usually non-infectious.
      • 150 mg/L → perforation, necrosis or severe infection (complicated appendicitis, Hinchey III–IV diverticulitis).
    • Procalcitonin
      • <0.5 ng/mL → non-severe infection.
      • 2 ng/mL → bacterial sepsis.
      • 10 ng/mL → septic shock.

  3. Electrolytes, kidney function, and blood gas analysis
    • Creatinine
      • Elevated: dehydration, kidney failure, sepsis
    • Lactate
      • 2 mmol/L: hypoperfusion
      • 4 mmol/L: septic shock or mesenteric ischemia
    • Sodium and Potassium
      • HipoK: ileus, muscle weakness, risk of arrhythmias
      • HiperK: Kidney failure, massive trauma
    • Arterial blood gas
      • Metabolic acidosis → sepsis, isquemia
      • Metabolic alkalosis → prolonged vomiting (high obstruction).

  4. Liver and pancreatic tests
    • Bilirubin
      • High direct → bile duct obstruction
      • High indirect → Hemolysis or early liver damage
    • Alkaline phosphatase (ALP) and GGT
      • Elevated → cholestasis, choledocholithiasis
    • Transaminases (AST/ALT)
      • Elevated → hepatitis, ischemia, toxicity
      • AST >> ALT → alcohol damage
    • Amylase/lipase
      • 3x above the limit → acute pancreatitis.

  5. Coagulation tests
    • Prolonged PT/INR and PTT → liver disease, sepsis, anticoagulant use
    • INR >1.5 preoperative → correct before surgery if possible

2. Surgical interpretation of the CT scan

The Contrast multidetector CT (CT C/A/P) es el principal estudio en emergencias quirúrgicas.

  1. CT scan in appendicitis
    • Suggestive findings:
      • Appendicular diameter >6 mm.
      • Periappendiceal fat infiltration.
      • Appendicolith.
      • Free fluid.
      • Extraluminal air → drilling.

  2. CT scan in diverticulitis
    • Sigmoid wall thickening.
    • Inflamed pericolic fat.
    • Abscesses → Hinchey II.
    • Outdoors → Hinchey III–IV.

  3. CT scan in intestinal obstruction
    • Key signs:
      • Dilation >3 cm (slim) or >6 cm (colon).
      • Air-liquid level.
      • Transition point.
      • Closed loop.
      • Wall thickening → ischemia.
      • Diminished enhancement → necrosis.

  4. CT scan in Pancreatitis
    • Pancreatic edema.
    • Peripancreatic collections.
    • Necrosis (>30% greater severity).
    • Necrotic gas → infection.

  5. CT scan in acute cholecystitis
    • Gallbladder thickening >3 mm.
    • Pericholecystic fluid.
    • Fatty striations.
    • “Positive sonographic Murphy's disease”.
    • Gas → Emphysematous cholecystitis (urgent surgery).

  6. CT scan in visceral perforation.
    • Subdiaphragmatic free air.
    • Retroperitoneal air.
    • Contaminated liquid or collection.
    • Adjacent loop thickening.

  7. CT scan in Mesenteric Ischemia
    • Parietal thickening.
    • Decreased enhancement.
    • Gas in the wall (pneumatosis).
    • Portal gas.
    • Visible blood clots.

  8. CT scan in abdominal trauma
    • Liver or spleen lacerations.
    • Hemoperitoneum.
    • Pneumoperitoneum.
    • Mesenteric hematomas.
    • Mild vs severe according to AAST.

1. How to present the interpretation in clinical practice

Students must report in a clear format:

  1. Laboratories
    • “Leukocytes 15,200 with neutrophilia of 85%, CRP 180 mg/L → suggests moderate-to-severe infection.”
    • “Lactate 3.8 mmol/L → possible hypoperfusion.”
  2. CT
    • Describe organ by organ.
    • Identify key signs.
    • Correlate with clinical findings.
    • Correlate with clinical findings.

2. Common mistakes a student should avoid

  • Relying solely on the laboratory without seeing the patient.
  • Saying “normal CT scan” without checking in detail.
  • Do not correlate pain with findings.
  • Failing to differentiate between inflammation and perforation.
  • Do not identify free air or free liquid.
  • Sartelli M, et al. WSES Guidelines for the management of acute abdomen. World J Emerg Surg. 2020;15:38.
  • Di Saverio S, et al. Diagnosis and treatment of acute appendicitis. WSES 2020 guidelines. World J Emerg Surg. 2020;15:27.
  • Pisanu A, et al. CT findings and severity assessment of diverticulitis. Eur J Radiol. 2021;139:109718.
  • Rondenet C, et al. Imaging of bowel obstruction. Radiographics. 2020;40:2151–2170.
  • Tenner S, et al. Management of acute pancreatitis. Am J Gastroenterol. 2020;115:322–339.
  • Yokoe M, et al. Tokyo Guidelines 2018: Acute cholecystitis. J Hepatobiliary Pancreat Sci. 2018;25:41–54.
  • Karaağaoğlu E, et al. CT in perforated peptic ulcer. Radiol Med. 2021;126:910–918.
  • Menke J. CT for detection of free air. Radiology. 2020;296:345–354.
  • Acosta S. Mesenteric ischemia: update 2021. Curr Opin Crit Care. 2021;27:101–107.
  • Bala M, et al. Acute mesenteric ischemia guidelines. Eur J Trauma Emerg Surg. 2020;46:453–476.
  • Stassen NA, et al. EAST Guidelines for trauma imaging. J Trauma. 2020;89:123–138.
  • Brody JM, et al. CT recognition of bowel ischemia. Insights Imaging. 2021;12:90.
  • De Cecco CN, et al. Multidetector CT in pancreatic emergencies. Radiol Clin N Am. 2020;58:223–239.
  • Frager DH. Bowels obstruction imaging review. Radiology. 2022;302:1–16.
  • Smith A, et al. Lab markers in surgical sepsis. Surg Infect. 2020;21:1–9.
  • Singer M, et al. Sepsis definitions and lactate interpretation. JAMA. 2020;324:775–788.
  • van Randen A, et al. Acute abdominal pain: diagnostic algorithm. BMJ. 2020;370:m3036.
  • Beal EW, et al. CT grading of liver and spleen trauma. J Trauma. 2021;90:1–12.
  • Biondo S, et al. Infections in abdominal surgery. Br J Surg. 2021;108:238–249.
  • Puylaert JB, et al. Imaging of appendicitis. Radiol Clin N Am. 2022;60:55–67.
  • Maconi G, et al. Imaging of peritonitis. Dig Liver Dis. 2020;52:772–780.
  • Linder JD, et al. Acute abdomen interpretation. Curr Opin Gastroenterol. 2021;37:525–533.
  • Coffin A, et al. CT of gastrointestinal emergencies. Radiographics. 2020;40:2151–2170.
  • Champion S, et al. Laboratory markers in abdominal emergencies. Surg Clin N Am. 2020;100:441–453.
  • Murphy KP, et al. Imaging pitfalls in emergency radiology. Radiol Clin N Am. 2022;60:89–103.
  • Wootton-Gorges SL. Pediatric acute abdomen imaging. Radiographics. 2020;40:1211–1231.
  • Shogan BD, et al. Surgical infections markers. Ann Surg. 2022;276:e295–e301.
  • Schellekens JFP, et al. Diagnostic accuracy of CRP and WBC. Br J Surg. 2020;107:e34–e43.
  • Mallick IH, et al. Gas patterns on CT in emergencies. Clin Radiol. 2021;76:578.e1–578.e8.
  • Elsayes KM, et al. Interpretation of liver imaging in trauma. Radiol Clin N Am. 2021;59:45–63.
  • Choi YR, et al. Advanced CT interpretation in surgical patients. Abdom Radiol. 2023;48:128–141.
  • Lee JY, et al. Radiology for acute abdominal pain. Lancet Gastroenterol Hepatol. 2024;9:90–102.

Interpreting clinical signs and applying validated surgical scales is an essential skill for any aspiring surgical student. These skills enable:

  • Recognize seriously ill patients quickly.
  • Prioritize interventions.
  • Deciding whether a patient needs immediate surgery.
  • Clearly communicate the severity to the surgical team.
  • Reducing diagnostic errors in emergency departments.

The following is presented comprehensive, modern summary applicable to daily practice.

1. Critical clinical signs in surgery

  1. Signos vitales (interpretación quirúrgica avanzada)
    • Tachycardia: First sign of surgical alarm. Key causes:
      • Occult bleeding.
      • Sepsis.
      • Intense pain.
      • Anxiety.
      • Dehydration.
      • Hollow Viscus Perforation.
      • In surgery NEVER underestimate a heart rate >100.
    • Tachypnea: The earliest sign of deterioration. Associated with:
      • Metabolic acidosis.
      • Sepsis.
      • Hemorrhagic shock.
      • Acute abdominal pain.
      • TEP (less frequent in initial emergency).
    • Hypotension: Late indicator of shock. Common surgical causes:
      • Abdominal septic shock.
      • Fecal peritonitis.
      • Massive gastrointestinal bleeding.
      • Abdominal trauma.
    • Fever: Key in abdominal patients. Think about:
      • Complicated appendicitis.
      • Diverticulitis.
      • Cholecystitis:
      • Abscesses.
      • Cholangitis.
      • Peritonitis.
      • Necrotizing fasciitis.
    • Abdominal pain. Anatomical interpretation:
      • Epigastrium: pancreatitis, perforated ulcer.
      • IDF: appendicitis.
      • RHC: cholecystitis, cholangitis.
      • Flank: Renal colic, retroperitoneal.
      • Generalized: peritonitis.
  2. Classic surgical signs
    • Blumberg (positive rebound): Pain when withdrawing the hand → peritoneal irritation. Suggests: perforation, peritonitis, advanced appendicitis.
    • Murphy: Pain and interruption of inspiration → acute cholecystitis.
    • Rovsing: Pain in the right iliac fossa upon palpation of the left iliac fossa → appendicitis.
    • Psoas: Pain with hip extension → retrocecal appendicitis or abscess.
    • Grey-Turner / Cullen: Bruising on the flank and periumbilical area → hemorrhagic pancreatitis.
    • Signs of shock
      • Cold skin.
      • Delayed capillary refill.
      • Mottled extremities.
      • Confusion.

2. Essential surgical scales

Below are the most relevant scales that every student should be familiar with.

  1. qSOFA (Quick SOFA) — Severe sepsis: Criteria:
    • FR ≥ 22.
    • PAS ≤ 100 mmHg.
    • Altered mental state.
    • ≥2 points = high risk of mortality → surgical alert.

       

  2. SOFA (Sequential Organ Failure Assessment): Evaluate the function of:
    • Lungs.
    • Coagulation.
    • Liver.
    • Cardiovascular.
    • SNC.
    • Kidneys.
    • Useful in postoperative septic patients or those with severe peritonitis.
  3. APACHE II — Surgical ICU: Predicts mortality. Includes: age, physiological state, temperature, HR, RR, BP, pH, Na, K, creatinine, hematocrit, leukocytes, Glasgow.
  4. Alvarado Score — Appendicitis: Components:
    • Migration of pain.
    • Anorexia.
    • Nausea/vomiting.
    • DIC pain.
    • Rebound.
    • Fever.
    • Leukocytosis.
    • Left deviation.
    • Interpretation: ≥7: probable appendicitis → consider surgery.

       

  5. AIR Score (Apendicitis Inflammatory Response): More modern than Alvarado. Includes: pain, rebound, fever, leukocytes, neutrophils, and PCR.
  6. Tokyo Guidelines – Cholecystitis / Cholangitis: They are used worldwide. They score:
    • Local signs of inflammation.
    • Leukocytes.
    • Fever.
    • Jaundice.
    • Biliary tract dilation.
    • Liver function.
    • Severity classification: I, II, III → guide for emergency surgery or drainage.

       

  7. Glasgow-Imrie — Acute pancreatitis: Evaluate severity by:
    • Age.
    • Leukocytes.
    • Glucose.
    • LDH.
    • AST.
    • Urea.
    • ≥3 points: severe pancreatitis.
  8. BISAP Score — Pancreatitis (more modern): Includes:
    • elevated BUN.
    • Mental disorder.
    • SIRS.
    • Age >60.
    • Pleural effusion.
    • ≥3 points → high risk.
  9. Hinchey — Diverticulitis
    • I: pericolic abscess.
    • II: pelvic abscess.
    • III: purulent peritonitis.
    • IV: fecal peritonitis.
    • Guide to surgical options: drainage, laparoscopy, Hartmann.
  10. Strangulation Criteria — Intestinal Obstruction: Absolute alarm:
    • Fever.
    • Tachycardia
    • Acidosis.
    • Leukocytosis.
    • Disproportionate pain.
    • Peritonitis.
    • High lactate.
    • Immediate surgery.
  11. LRINEC — Necrotizing fasciitis: Includes: CRP, leukocytes, hemoglobin, sodium, creatinine, glucose. ≥8 points = high risk.
  12. Traumashock/ATLS criteria
    • FAST positive.
    • Hypotension
    • Distended abdomen.
    • TEP differentials.
    • Laparotomy decision guide.

1. How to use scales in practice

  1. First, recognize the clinical signs (what you see and hear).
  2. Apply rapid scales (qSOFA, Alvarado, BISAP).
  3. Classify the patient (mild, moderate, severe).
  4. Decide whether a patient needs immediate surgery. or complementary studies.
  5. Communicate effectively with the surgeon using technical language.
  6. Document everything (hora, signos, cambios, escalas aplicadas).
  7. They can use a scoring app like this one.

2. Practical example

Patient 38 years old, right lower quadrant pain, fever, tachycardia, positive rebound.
Laboratory results: leukocytes 15,000, elevated CRP.

Interpretation:

  • Alvarado: 8
  • AIR: high risk
  • qSOFA: 0 (not septic yet)
  • → Probable appendicitis → surgery.

Another example:

  • Elderly patient with diffuse pain, tachypnea, hypotension, confusion.
  • qSOFA = 3
  • → Severe sepsis.
  • Possible perforation.
  • → Urgent laparotomy.
  • Singer M, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2020.
  • Yokoe M, et al. Tokyo Guidelines 2018–2022 for acute cholangitis and cholecystitis. J Hepatobiliary Pancreat Sci.
  • van Randen A, et al. Acute appendicitis: meta-analysis of clinical signs and scores. BMJ. 2021.
  • Sartelli M, et al. WSES guidelines for acute abdomen. World J Emerg Surg. 2020.
  • Kiewiet JJS, et al. A systematic review and meta-analysis of diagnostic performance of scoring systems in appendicitis. Br J Surg. 2020.
  • Machesky M, et al. BISAP Score Accuracy in Acute Pancreatitis Severity Prediction. Pancreas. 2022.
  • McIsaac DI, et al. Severity scoring systems for surgical sepsis. Br J Anaesth. 2020.
  • Lobo DN, et al. Perioperative physiological and scoring systems. Surg Clin North Am. 2021.
  • Sartelli et al. Acute abdomen in the emergency setting: global updated guidelines. World Journal of Emergency Surgery. 2022.
  • Gupta S, et al. Necrotizing soft tissue infections: LRINEC score revisited. J Trauma Acute Care Surg. 2023.
  • Biondo S, et al. Management of diverticulitis. Lancet Gastroenterology. 2021.
  • Coccolini F, et al. Perforated Peptic Ulcer guidelines. World J Emerg Surg. 2020.
  • Di Saverio S, et al. WSES guidelines for emergency bowel obstruction. World J Emerg Surg. 2021.
  • Gandhi SK, et al. Predictors of strangulated bowel. J Gastrointest Surg. 2023.
  • Bala M, et al. WSES guidelines for acute mesenteric ischemia. World J Emerg Surg. 2022.
  • El Hechi M, et al. Damage Control Surgery: Review. Trauma Surg Acute Care Open. 2021.
  • Coccolini F, et al. Peritonitis classification and management. World J Emerg Surg. 2021.
  • Lee Y, et al. Interpretation of vital signs in surgical sepsis. Crit Care. 2022.
  • Leeuwenburgh MM, et al. AIR Score evaluation. Ann Surg. 2020.
  • Moller MH, et al. Early warning scores in surgical patients. Br J Surg. 2021.
  • Tran A, et al. Predictive value of qSOFA in acute surgical abdomen. Surgery. 2022.
  • Coimbra R, et al. Surgical Infection Society Guidelines. Surg Infect. 2021.
  • Regner JL, et al. Clinical signs in perforated viscus. J Trauma Acute Care Surg. 2023.
  • Warlin J, et al. Predictive markers in mesenteric ischemia. Ann Surg. 2021.
  • Azzopardi N, et al. A systematic review of peritonitis scores. J Surg Res. 2021.
  • Kokoska ER, et al. Pediatric emergent scores. J Pediatr Surg. 2021.
  • Fukami Y, et al. Trauma scoring systems update. Trauma Surg Acute Care Open. 2022.
  • Lobo DN, et al. Acute care surgery physiology. Surg Clin North Am. 2023.
  • Katergiannakis V, et al. Emergency hernia complications. Hernia. 2020.
  • De Simone B, et al. SIRS criteria usefulness revisited. World J Surg. 2021.
Scroll to Top