Course Case Studies
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Several observational studies point to a strong association between hyperglycemia and poor surgical outcomes, including on measures of length of stay, infection rates, posthospitalization disability, and mortality [62]. One well-studied population is cardiovascular surgery patients, partially because individuals with diabetes are at increased risk for cardiovascular disease and frequently require coronary artery bypass and grafting. Hyperglycemia, whether related to diabetes or stress, is associated with suboptimal outcomes when experienced on the first post-operative day after cardiovascular surgery [63]. However, the impact of diabetes on the risk of cardiothoracic surgical site infection and other poor outcomes may not simply be related to alterations in glucose control. Patients with diabetes are more likely to possess other factors associated with poor surgical outcomes, including obesity [61].
When hyperglycemia is present, there is an impact on fibroblast function during the period of granulation tissue formation and maturation. Decreased levels and cross-linking of collagen may impair wound healing and strength [14]. For these reasons, patients with diabetes preparing for a surgical intervention should maintain as close to normal metabolic functioning as possible. Therapeutic goals should include avoidance of hypoglycemia, hyperglycemia, lipolysis, ketogenesis, proteolysis, dehydration, and electrolyte imbalance [14].
The Institute for Clinical Systems Improvement asserts that determination of a patient's glycemic control status is an important factor in preventing surgical-site infection. In patients with diabetes, glycemic control should be directed at achieving blood glucose levels between 140 and 180 mg/dL, and not be directed at more intensive goal targets (80–110 mg/dL)
(https://www.icsi.org/wp-content/uploads/2019/01/Periop.pdf Last Accessed: September 20, 2023)Strength of Recommendation/Level of Evidence: Strong recommendation, high-quality evidence
There is significant research regarding the benefit of glycemic control after surgery, specifically after cardiac surgical interventions. One study revealed that improvements in postsurgical cardiac surgery glucose control were linked to a reduction in mediastinitis [60]. Some reviews recommend target presurgical glucose levels in the 100–180 mg/dL range because this level of glycemia has been shown to prevent infection, risk of hypoglycemia, and dehydration as a result of osmotic diuresis [14]. Although hyperglycemia is associated with adverse patient outcomes, controversy remains as to the appropriate levels required to prevent adverse outcomes while also avoiding potentially detrimental hypoglycemia [62,64]. A 2017 study of 300 patients with hyperglycemia (50% with diagnosed diabetes) who underwent cardiac surgery, found that intensive (100–140 mg/dL) and conservative (141–180 mg/dL) glucose control regimens produced similar circulating markers of acute inflammatory and oxidative stress response [63].
In addition to hyperglycemia, obese patients with or without diabetes have a significantly increased risk of impaired wound healing than those of normal weight [60]. Severe obesity is associated with venous stasis disease, pitting pretibial edema, bronze edema (a result of extravasation of red blood cells into the skin), cellulitis, and obesity hypoventilation [65]. Furthermore, obesity is a known risk factor for surgical-site infection. Patients with diabetes have been shown to have increased carriage rates for Staphylococcus aureus colonization, a leading cause of surgical-site infection [61]. These conditions impact the body's ability to heal an incision, potentially leading to wound dehiscence, rhabdomyolysis, and complications of the skin and underlying tissue [60].
Wound dehiscence is a serious complication for all obese patients whether or not they have diabetes. However, as previously stated, when hyperglycemia is present, wound healing and strength is impaired; when both are present, the risk of delayed healing is even greater [14]. In the early postoperative period, wounds stay approximated due to the strength of the sutures or the normal healing process as the muscle regains its strength. Consequently, obesity, heavy coughing or retching, and ascites can strain the wound and result in dehiscence [33].
A wound is at greatest risk of dehiscence in the first two weeks following surgery, when the wound is still fresh and very fragile. When dehiscence does occur, it can be mild (e.g., a small area of the incision begins to pull apart and leave a gap) or severe, causing the sutures, staples, or surgical glue to completely give way and the entire incision to open. In severe cases, the open incision is a surgical emergency and medical attention should be obtained immediately [66].
When wound dehiscence occurs, swift detection and action is critical. Interventions include antibiotic therapy and analgesics [67]. When appropriate, exposing the wound to air may accelerate healing by allowing growth of new tissue from below and preventing infection. Surgical removal of contaminated and dead tissue may also be necessary. A temporary or permanent piece of mesh may be placed to bridge the gap in the incision or wound. Vacuum-assisted wound closure may be used to increase granulation tissue and remove excess drainage. When appropriate, frequent changes in the incisional dressing are required to prevent infection.
Patient M is a White man, 67 years of age, with type 2 diabetes who is admitted to the hospital with a fever, two-day history of lethargy, and a rapid decrease in level of consciousness. His vital signs on admission are: temperature, 39.7 degrees Celsius; heart rate, 112 beats per minute, regular rate and rhythm; 26 respirations per minute and shallow; blood pressure, 88/40 mm Hg; blood glucose level, 329 mg/dL. The patient is complaining of a severe pain, reported at a 7 on a scale from 1 to 10. Physical assessment indicates:
Height: 5 feet 10 inches
Weight: 239 pounds without shoes
Body mass index: 34.4 kg/m2
Lungs: Crackles upon auscultation
Heart sounds: Clear without rubs or murmurs auscultated
Abdomen: Soft and non-tender all quadrants
Peripheral pulses: Present upon Doppler assessment at the lower extremities
Feet and lower extremities: Cool to touch, hairless and shiny, taut, and thin bilaterally. Toes mottled.
Capillary refill: Absent
Two lesions are present on the left lateral lower extremity, approximately 4 cm distal to the malleolus. The lesions are 5 cm in length, 3 cm in width, superficial depth, with yellowed edges, pale red base, and weepy.
Laboratory values reveal:
Blood cultures positive forS. aureus
White blood cell count: 21,000/mcL
Glycated hemoglobin (HbA1c): 8.5%
pH: 7.29
Patient M is admitted to the hospital with a diagnosis of septicemia secondary to a venous stasis ulcer, peripheral vascular disease, and uncontrolled hyperglycemia related to infection. He is started on antibiotic therapy, pain management, and dressing changes.
On day three of therapy, Patient M's temperature has been stabilized for the past 24 hours. Laboratory values are normalizing. His blood glucose levels remain elevated, with measurements between 276 mg/dL and 310 mg/dL. His pain is fluctuating between a 1 and a 5 and is being controlled with analgesics. Patient M's wound drainage is scant and yellow in color, with a slightly foul odor. His treatment plan consists of a moist, non-adherent dressing, and improvements have been noted. After three weeks of treatment, the wound assessment documentation indicates one lesion present on the left lateral lower extremity, approximately 4 cm distal to the malleolus. It is 4.6 cm in length, 2.8 cm in width, and superficial depth. The lesion is dry with irregular, yellowed edges and a reddened base. The surrounding tissue remains shiny and ruddy in color.
Patient M is discharged with orders for home health care for wound assessment and antibiotic therapy via a midline catheter.
Patient J is a White female patient, 54 years of age, with a history of uncontrolled insulin-dependent diabetes for the past 10 years. She is obese, with a body mass index of 41 kg/m2. She reports a history of shortness of breath with minimal exertion and severe bilateral osteoarthritis of the knees. She was a two-pack-per-day smoker but has been cigarette-free for the past six months. She is scheduled for gastric bypass surgery in two days. Presurgical teaching includes:
Incisional support and care to prevent infection
Techniques for turning, coughing, and deep breathing after surgery
The need to turn/change position at least every two hours to prevent pressure injuries
The surgery is completed without incident, and Patient J appears to be recovering as expected. However, two weeks postoperative she begins to cough uncontrollably, neglecting to support her incision. This occurs a total of four times throughout the night. At approximately 4:00 a.m., Patient J feels her incision "let go" and begins to bleed profusely; her incision has dehisced. She is rushed into surgery to resecure the incision and stop the bleeding. Although the bleeding can be cauterized, the periwound is too friable and further suturing will not adhere.
Patient J's incision measures 15 cm from twelve o'clock to six o'clock, 10 cm from three o'clock to nine o'clock, and 6 cm in depth. It is beefy red in color and appears to be healthy, with granulation tissue present. The surgeon prescribes treatment of the dehisced incision with a vacuum-assisted closure. She is premedicated for pain prior to dressing initiation and for subsequent dressing changes every 48 to 72 hours. After three weeks of vacuum-assisted closure therapy, Patient J's incision measures 12 cm from twelve o'clock to six o'clock, 9 cm from three o'clock to nine o'clock, and 4 cm in depth. It continues to look healthy and show signs of granulation. No odor is present within the wound. Wound edges are healthy, without maceration or rolling. The vacuum-assisted closure therapy is continued. At Patient J's next appointment eight weeks after the surgical procedure, her incision is assessed to be 8 cm from twelve o'clock to six o'clock, 5 cm from three o'clock to nine o'clock, and 2 cm in depth, with healthy color and edges. Vacuum-assisted closure therapy is discontinued, and a saline dressing is applied. Patient J's surgery is a success for both weight loss and the healing of her dehisced wound.
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- Participation Instructions
- Review the course material online or in print.
- Complete the course evaluation.
- Review your Transcript to view and print your Certificate of Completion. Your date of completion will be the date (Pacific Time) the course was electronically submitted for credit, with no exceptions. Partial credit is not available.