The impact of closed incision negative pressure therapy on prevention of median sternotomy infection for high risk cases: a single centre retrospective study.

BACKGROUND: Sternal wound infection (SWI) following cardiothoracic surgery is a major complication. It may significantly impact patient recovery, treatment cost and mortality rates. No universal guideline exists on SWI management, and more recently the focus has become prevention over treatment. Recent studies report positive outcomes with closed incision negative pressure therapy (ciNPT) on surgical incisions, particularly for patients at risk of poor wound healing.

OBJECTIVE: This study aims to assess the effect of ciNPT on SWI incidence in high-risk patients.

METHODS: A retrospective study was performed to investigate the benefit of ciNPT post sternotomy. Patients 3 years before the introduction of ciNPT (Control group) and 3 years after ciNPT availability (ciNPT group) were included. Only patients that had two or more of the risk factors; obesity, Chronic Obstructive Pulmonary Disease, old age and diabetes mellitus in the High Risk ciNPT cohort were given the ciNPT dressing. Patient demographics, EuroSCOREs and length of staywere reported as mean ± standard deviation. The Fisher's exact test (two-tailed) and an unpaired t-test (two-tailed) were used to calculate the p-value for categorical data and continuous data, respectively.

RESULTS: The total number of patients was 1859 with 927 in the Control group and 932 in the ciNPT group. No statistical differences were noted between the groups apart from the Logistic EuroSCORE (Control = 6.802 ± 9.7 vs. ciNPT = 8.126 ± 11.3; P = 0.0002). The overall SWI incidence decreased from 8.7 to 4.4% in the overall groups with the introduction of ciNPT (P = 0.0005) demonstrating a 50% reduction. The patients with two and above risk factor in the Control Group (High Risk Control Group) were 162 while there was 158 in the ciNPT Group (High Risk ciNPT Group). The two groups were similar in all characteristics. Although the superficial and deep sternal would infections were higher in the High Risk Control Group versus the High Risk ciNPT group patients (20(12.4%) vs 9(5.6%); P = 0.049 respectively), the length of postoperative stay was similar in both (13.0 ± 15.1 versus 12.2 ± 15.6 days; p + 0.65). However the patients that developed infections in the two High Risk Groups stayed significantly longer than those who did not (25.5 ± 27.7 versus 12.2 ± 15.6 days;P = 0.008). There were 13 deaths in Hospital in the High Risk Control Group versus 10 in the High Risk ciNPT Group (P = 0.66).

CONCLUSION: In this study, ciNPT reduced SWI incidence post sternotomy in patients at risk for developing SWI. This however did not translate into shorter hospital stay or mortality.