Post-Surgical Complications

Author: Sreeja Natesan, MD (EM Attending Physician / Assistant Program Director, Duke University Medical Center) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UT Southwestern Medical Center / Parkland Memorial Hospital) and Brit Long (@long_brit)

Case: A 65-year-old male with PMH of HTN and DM presents to the ED with complaints of abdominal pain.   He states he had emergent surgery for perforated appendicitis more than 1 week prior and has been home recovering.  For 3 days prior to presentation, he has had increasing pain at the incision site and associated nausea with decreased oral intake.  ROS is otherwise negative.  Vital signs reveal fever and tachycardia.  Exam demonstrates a post-surgical scar with tenderness to palpation over this area.   What is your next step?


How common are post-surgical complications?

Post-surgical complications are a major concern and timely identification of the potential etiologies is crucial to decreasing morbidity and mortality.1  The words ‘post-surgical’ and ‘post-operative’ are often used interchangeably.  Although it is unclear the factors that improve outcomes, the substantial proportion of complications and death within 90 days after major surgery occur after discharge from the hospital and up to 25% require readmission. 2 The words ‘post-operative’ or ‘post-surgical’ encompasses both the open approach and minimally invasive surgery (MIS).  MIS can utilize both tradition and robot-assisted laparoscopic approaches and is increasingly becoming the standard of care for certain urologic abdominal and pelvic surgeries due to its ability to decrease hospital length of stay (LOS), narcotic requirement, and recovery time.3

Post-operative complications are a major focus of Surgical Care Improvement Project for the Centers of Medicare and Medicaid Services (CMS), which targets three major areas including surgical site infection (SSI), venous thromboembolism (VTE), and cardiac ischemia.  In certain cases, CMS has even withheld payment when certain preventable complications have occurred. However, in many studies using risk adjustment, the relationship with complications and overall mortality disappears, suggesting that patient factors rather than quality of care is the main driver of these complications.1  The factors leading to the complications have yet to be elucidated.

Two factors that are essential to rescue the patient from complications include timely recognition of the complication and effective management of that complication. 1 A systematic approach to addressing these complications is imperative to ensure the best outcome for the patient.  Particularly for post-operative fever, a focused approach should be utilized rather than the typical “shotgun” fashion that is often seen.4

The incidence of post-operative complication can be seen on the below chart, and the various etiologies vary depending on the amount of time that has passed since the actual surgery.5


What are the most common post-surgical complications? 

Post-surgical complication can affect many systems aside from the location where the surgery was performed.  It is important to consider this when evaluating the patient to maintain a broad differential of the potential causes that may lead to the patient’s presentation to the ED.

A common mnemonic to aid in identifying the eliciting factors causing the post-operative complication is the “Rule of W’s”: Wind, Water, Walk, Wound, Wonder Drugs.4,5,6

However, in the immediate post-operative period, a revision to this mnemonic has been suggested including an additional “W” which is “Waves” meaning electrocardiogram waves because myocardial infarction is the most common complication on POD 0.5

The updated summary of Rule of W’s: mnemonic for postoperative complication timing and frequency, regardless of fever:6

However, an article by Sonneberg, et al. entitled7 “Wind, water, wound, walk- do the data deliver dictum?” found that the “Rule of W’s” should be applied to the correct clinical setting stating “The dictum should be taught as, “wind, water, walk, wound” to reflect the timing and progression of the diagnosis of PNA, UTI, VTE, and SSI. The dictum did not reflect the timing or sequence of the occurrences in the cohort diagnosed after discharge. Educators must teach trainees to apply the dictum in the appropriate patient setting.”  In addition, in the immediate postoperative patient with fever, atelectasis was thought to be the first consideration. However one review suggests it is not clearly related to fever.8 It is also thought that DVT is not as common as previously suggested by this mnemonic, and the classic teaching as seen in the below chart that illustrates the index complication during the 14 and 30 post-operative period varies.5

Important items in history and physical examination

History pearls

It is important to obtain specific historical information to help better decide the potential cause of the patients’ presentation to the emergency department.8  Questions regarding chief complaint can also help guide what system the patient’s complication could involve.  It is important also to focus on a thorough surgical history with information including the date of the surgery, current postoperative day, surgical approach (open versus MIS), and what it entailed.  Additionally, any perioperative or immediate postoperative complications that affected care should be reviewed, as this may be a clue to a potential complication.  Elective versus emergent surgery is important to ascertain, as emergent surgeries do not have the ability to obtain pre-operative risk factors and have been found to hold a 1.26 fold increase in the risk of major postoperative morbidity and 1.39 fold increase in the risk of postoperative death when compared to elective surgeries.9

In addition, an updated medication reconciliation should be performed including any antibiotics, analgesics, and anticoagulants.  This information can help in deciphering the etiology of the complication.

Physical exam pearls

Vitals signs are crucial in the evaluation of a post-operative patient although normal vital signs can be present in certain situations (see box).10  A post-operative fever is defined as a temperature of >100.4ºF.  The time of onset of the fever can also help to guide the physicians’ differential as seen in the accompanying graph of post-operative date, fever, and etiology.8

Tachypnea or hypoxia may suggest infection or a pulmonary embolism as the etiology.  Hypotension may be suggestive of sepsis and warrant immediate resuscitation.  Tachycardia may be suggestive of pain or infection although a broad differential should be maintained to determine the etiology.10

Careful evaluation of the wound is important to decipher if there is dehiscence or infection present.  Overlying erythema or induration may suggest the presence of infection.  Characteristics of drainage is also important to note as it may suggest a seroma, hematoma, or abscess. Serous fluid typically results due to the liquefying of a hematoma from the depths of the wound and is of little significance.  The presence of serosanguinous discharge 5-7 days out can be a herald of a potential dehiscence, especially if it was preceded by a coughing or vomiting episode.11

Below is an illustration with the potential common post-operative complication and pertinent clinical examination findings that may be present and help distinguish the etiology.

Diagnostic Considerations

Laboratory Testing

Infectious causes should be considered in patients who are presenting with fever later than 48 hours after surgery with non-infectious causes being the main source of fever within the immediate 48 hours postoperative period.  A fever that begins on or after POD5 should be considered a clinically significant infection until proven otherwise and an infectious workup should be undertaken.   Infectious workup can include laboratory investigations ranging from complete blood counts, blood cultures, urine cultures, and imaging (plain films, CT).8


Computed Tomograph (CT scan) of the abdomen/pelvis is often warranted in evaluation for the various complications during the postoperative period including infection, obstruction, ileus, or surgical leak.  It is important to consider IV contrast to help in deciphering structures10 and evaluating for the above complications.  If a vascular abdominal surgery was performed, the use of CT angiography may be considered to highlight the vascular structures of interest particularly if the patient has undergone an open vascular repair.10,12  A FAST/eFAST exam should be considered in the hypotensive undifferentiated patient to help determine the etiology of shock.10

Medication Considerations

Pain is often the driving complaint that has brought the patient to the emergency department.  Previously, withholding analgesia was considered the standard due to concern of “masking” the symptoms.  However, research has largely falsified this practice.10 When considering treatment, opiates remain the mainstay in treatment of pain13 although when used in isolation, the limitation of opioid analgesia after surgery is its inability to control pain on movement.  Acetaminophen is an effective adjunct to opioid analgesia, reducing pain scores and requirements for opioid analgesia by 20-30%.14

A variety of antiemetics are available for treatment of nausea.  Ondansetron is a common, safe, and readily available medication.  It is often the first line in treating nausea due to its lack of sedative quality seen in promethazine or risk for akathisias seen with metoclopramide and prochlorperazine.  Currently, there are no studies demonstrating a statistically significant difference in medication efficacy.10 

Post-surgical Complication Management Pearls based on Differential Diagnosis

Clostridium Difficile Infection

Approximately 20-50% of hospitalized patients are colonized by this organism, and infection by C. Difficile can occur after the administration of an antibiotic that alters the normally protective flora of the bowel.8 A high risk patient is one who presents with an acute abdomen and has received antibiotics within the past 2 months.  At worst, C.Difficile infection can result in toxic megacolon which is a surgical emergency requiring subtotal colectomy.  A stool sample should be obtained to detect the cytotoxic toxin, and empiric antibiotics should be started with vancomycin (oral or per rectum) or metronidazole (intravenous or oral).8

Early Postoperative Small Bowel Obstruction (EPSBO)

Similar in its presentation as ileus, EPSBO differs in that it can yield more serious sequela.  Incidence rate can be as high as 5-10%.  Open procedures such as colectomy, omentectomy, and pelvic dissection carry the highest risk of EPSBO, whereas laparoscopic surgery is associated with a lower incidence.  The imaging modality of choice is CT which is considered gold standard in distinguishing POI from EPSBO.  A nasogastric tube (NGT) should be placed if an EPSBO is found.  Water soluble contrast such as Gastrograffin is safe in the GI tract or peritoneal space and should be infused through the NGT with an upper GI series being done, as this accurately predicts the need for surgery and is associated with shorter hospital stays.15 Barium should be avoided due to its viscous nature which can exacerbate a partial SBO and cause peritonitis if a perforation exists.   The majority (90%) of EPSBO resolve with NGT alone within 6 days, with 10% requiring relaparotomy.15

Necrotizing Soft Tissue Infections (NSTIs)

This necrotizing infection is typically invasive and carries with it a high morbidity and mortality rate.  It may present as Fournier gangrene, necrotizing fasciitis, clostridial gas gangrene, and invasive streptococcal cellulitis.8 The time of onset varies and can be within hours of surgery to several days post op.  A clinical clue includes “dishwater drainage”, edema, erythema, induration, bullae, and pain out of proportion to exam findings.  Patients at particular risk for NSTI include those with vascular disease, diabetes mellitus, alcohol abuse, obesity, poor nutrition, NSAID use, or immunocompromised patients.8   Necrotizing infection requires surgical debridement, and preoperative labs as well as cultures should be sent during the initial period of evaluation.  Prompt surgical consultation and early empiric, broad-spectrum antibiotics are crucial.


Postoperative patients are at risk for developing pneumonia due to postoperative pain that limits mobility, ability to cough, and inspiratory effort.  This risk is increased in those who undergo mechanical ventilation, even for a short period of time.8,17  Post-operative pneumonia incidence can range from 1.5% to as high as 15.3% in high-risk groups with a 30 day post-operative mortality for all groups as high as 21%.16,17 This is dependent on patient comorbidities, illness severity, and the causative pathogen.  The clinical characteristics are typically fever and purulent sputum with shortness of breath.  Laboratory evaluation may demonstrate leukocytosis.  Hypoxia should be addressed with supplemental oxygen.17 Evaluation of pneumonia includes a thorough physical exam, laboratory evaluation, chest radiography, and consideration of broad-spectrum antibiotics.8,17

Postoperative Ileus (POI)

Although not life-threatening, POI is a frequent occurrence, particularly after abdominal surgery, and carries with it an associated prolonged postoperative recovery, LOS, increased cost, and healthcare resources utilization.15,18 Fluid overload, exogenous opiate, neurohormonal dysfunction, along with inflammation, are the main pathophysiological culprits leading to a POI15 often making it perceived as an unavoidable outcome of major abdominal surgery.  In particular, the opiate dose that slows peristalsis is 25% the dose required to achieve adequate analgesia,15 thus explaining why ileus is such a common phenomenon.14 Poor nutritional status can arise due to the nausea and vomiting from the POI, leading to impaired wound healing.  The resultant distension of the abdomen from the POI can also potentially cause hernia formation or wound dehiscence. Clinical presentation include abdominal pain and distension, nausea, vomiting, inability to tolerate diet, and inability to pass flatus.   CT scan is considered the gold standard because it can help decipher between POI and small bowel obstruction.  Treatment of POI centers on bowel rest, limiting opioid use, ambulation, and electrolyte management.  Insertion of NG tube has not been associated with early return of bowel function although this may be necessary in the patient with vomiting related to POI in order to facilitate GI decompression.  Normal POI should last 3 days for laparoscopic surgery and up to 5 days for open surgery after a bowel resection.15

Post-surgical Wound Infection or Surgical Site Infection (SSI)

Surgical site infection (SSI) is a common infection that can occur in about 3% of all surgical procedures and up to 20% of patients who require emergent intra-abdominal surgery.16,19 Mortality rates for specific procedures double when the patient develops an SSI and triple the odds of death from SSI in elderly when compared with younger patients.19  Below is a chart that shows the SSI rate based on wound classification and definition.19,20

Staphylococcus species account for nearly 50% of infections with MRSA accounting for 13.7%.19,20  However, in intra-abdominal procedures, SSI are roughly equally caused by gram-positive and gram-negative organisms.16  Risk factors that affect wound healing include diabetes mellitus, immunosuppression, malignancy, and malnutrition.19

SSI is categorized into superficial incisional, deep incisional, and organ/space SSI (see accompany picture by CDC).16

SSI risk is strongly associated with wound classification.   Abscesses can form after any type of surgical procedure, particularly if the abdominal compartment is contaminated8 and can occur during any open, interventional, endoscopic, laparoscopic, or robotic assisted procedure.  The time to presentation to the emergency department can vary from 1 week to upwards of several months.8  Radiological imaging such as CT scan are utilized to help determine the diagnosis.

Successful treatment of SSI centers around 4 main principles seen in the accompanying box.16,19

The main focus of SSI treatment is aimed at source control of the infection. Drainage of the infection is considered paramount and antibiotics are secondary as many superficial infections do not necessarily require antibiotics if drained thoroughly.  For skin and subcutaneous infections, these may be drained directly remembering to obtain cultures. However, deep or organ space infections may require imaging-directed percutaneous drain placements or procedures.  Patients with deep infections or those that present with clinical signs of systemic inflammatory response syndrome or sepsis will require empiric antibiotic therapy to cover suspected organisms depending on the source.19  Prompt surgical consultation should be considered in addition to treating with broad-spectrum antibiotics.8

Urinary Tract Infection (UTI)

UTIs are the most common hospital acquired infection (HAI).8,16 Urinary catheters are used in up to 25% of all hospitalized patients and 5-10% of nursing home residents. Catheter associated UTI has not been directly linked with mortality, although it has been associated with approximately 20% of hospital acquired bacteremia, a diagnosis that carries with it a mortality of 10%.16  The greatest risk occurs in patients with prostate disease, those patients who underwent spinal anesthesia, or those who have undergone anorectal surgery. The fever associated with UTI typically occurs POD 3-5 and may be accompanied by abdominal pain or an ileus.  Common pathogens include E. coli, Klebsiella, Enterobacter, Pseudomonas, and Serratia.  The management centers on evaluation of the urine by urine analysis and culture.8

Venous Thromboembolism (Deep vein thrombosis/Pulmonary Embolism)

VTE continues to remain one of the most common preventable causes of in-hospital mortality.  D-dimer has a high sensitivity (98%) but moderate specificity (50%) and should not be used in surgical patient, pregnant patients, or those patients who have cancer.16  A fever can be seen with pulmonary embolism(PE), although it is typically low grade (temperatures rarely exceeding 38.3ºC [101ºF]).  Septic thrombophlebitis subsequently causing septic pulmonary embolism may result in fever as well.8 In patients who are presenting with PEs with accompanying hemodynamic instability, the patient should undergo (in order of preference) thrombolytic therapy, catheter assisted thrombolectomy, or surgical pulmonary embolectomy,16 although discussion with the surgeon should be considered in conjunction to treatment.


Early consultation with the operative team can help the clinician clarify the desired diagnostic approach and help target management.8 If the patient is presenting with postoperative fever, the definitive treatment requires identifying the source of infection.  Timely use of broad-spectrum antibiotics is crucial to preventing the patient from progressing from fever to multi-system organ dysfunction from sepsis.8

A recent review in the Lancet suggests that when complications occur after a major surgical procedure, returning the patient to the index hospital to be cared for by the original surgical team can help to achieve significantly improved 90 day survival rather than admission to a non-index hospital. 2

Pearls and Pitfalls

  • A thorough history and physical examination is essential in identifying postoperative complications.
  • A modified “Rule of W’s” should be considered in immediately postoperative patients including Waves, Wind, Water, Wound, Walking, Wonder Drugs.
  • Early surgical consultation can help guide the diagnostic and therapeutic management.
  • Consider early antibiotics in patients who appear with fever and concerns for sepsis.

Case Resolution

The laboratory results revealed leukocytosis.  His subsequent CT scan of his abdomen revealed concerns for an abscess.  The patient was started on antibiotics and had a drain placed under interventional radiology.  He was admitted to the hospital for further management.

References/Further Reading

  1. Ghaferi, A. A., Birkmeyer, J. D., & Dimick, J. B. (2009). Variation in Hospital Mortality Associated with Inpatient Surgery.New England Journal of Medicine,361(14), 1368-1375.
  2. Brooke, B., Goodney, P., & Kraiss, L. (2016). Readmission Destination and Risk of Mortality After Major Surgery: An Observational Cohort Study.Journal of Vascular Surgery,63(4), 1126.
  3. Kaplan, J. R., Lee, Z., Eun, D. D., & Reese, A. C. (2016). Complications of Minimally Invasive Surgery and Their Management.Current Urology Reports,17(6).
  4. Pile, J. C. (2006, March). Evaluating postoperative fever: a focused approach. Retrieved June 01, 2017, from
  5. Cole, C. (2016, March 3). Postoperative Complications: Revising the Rule of W. Retrieved May & June, 2017, from
  6. Hyder, J. A., Wakeam, E., Arora, V., Hevelone, N. D., Lipsitz, S. R., & Nguyen, L. L. (2015). Investigating the “Rule of W,” a Mnemonic for Teaching on Postoperative Complications.Journal of Surgical Education,72(3), 430-437.
  7. Sonnenberg, E. M., Reinke, C. E., Bartlett, E. K., Collier, K. T., Karakousis, G. C., Holena, D. N., & Kelz, R. R. (2015). Wind, Water, Wound, Walk—Do the Data Deliver the Dictum?Journal of Surgical Education,72(1), 164-169.
  8. Narayan, M., & Medinilla, S. P. (2013). Fever in the Postoperative Patient.Emergency Medicine Clinics of North America,31(4), 1045-1058.
  9. Mccoy, C. C., Englum, B. R., Keenan, J. E., Vaslef, S. N., Shapiro, M. L., & Scarborough, J. E. (2015). Impact of specific postoperative complications on the outcomes of emergency general surgery patients.Journal of Trauma and Acute Care Surgery,78(5), 912-919.
  10. Natesan, S., Lee, J., Volkamer, H., & Thoureen, T. (2016). Evidence-Based Medicine Approach to Abdominal Pain.Emergency Medicine Clinics of North America,34(2), 165-190.
  11. Beattie, S. (2007, June). Bedside Emergency: Wound Dehiscence. Retrieved May & June, 2017, from
  12. Nayeemuddin, M., Pherwani, A., & Asquith, J. (2012). Imaging and management of complications of open surgical repair of abdominal aortic aneurysms.Clinical Radiology,67(8), 802-814.
  13. Lovich-Sapola, J., Smith, C. E., & Brandt, C. P. (2015). Postoperative Pain Control.Surgical Clinics of North America,95(2), 301-318.
  14. Power, I., & Barratt, S. (1999). Analgesic Agent for the postoperative period.Surgical Clinics in North America,79(2), 275-294.
  15. Doorly, M. G., & Senagore, A. J. (2012). Pathogenesis and Clinical and Economic Consequences of Postoperative Ileus.Surgical Clinics of North America,92(2), 259-272
  16. To, K. B., & Napolitano, L. M. (2012). Common Complications in the Critically Ill Patient.Surgical Clinics of North America,92(6), 1519-1557.
  17. Sachdev, G., & Napolitano, L. M. (2012). Postoperative Pulmonary Complications: Pneumonia and Acute Respiratory Failure.Surgical Clinics of North America,92(2), 321-344. doi:10.1016/j.suc.2012.01.013
  18. Bragg, D., El-Sharkawy, A. M., Psaltis, E., Maxwell-Armstrong, C. A., & Lobo, D. N. (2015). Postoperative ileus: Recent developments in pathophysiology and management.Clinical Nutrition,34(3), 367-376.
  19. Nix, S., & Albrecht, R. (2011, December 06). Surgical Site Infections – Preventable or Predictable. Retrieved June 01, 2017, from—Preventable-or-Predictable.aspx
  20. Young, P. Y., & Khadaroo, R. G. (2014). Surgical Site Infections.Surgical Clinics of North America,94(6), 1245-1264.

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