Hyperbaric oxygen was used in fewer than one percent of these surgical NSTI admissions, yet that small group had markedly lower mortality and amputations. The catch: treatment also meant longer stays and higher costs. Necrotizing soft tissue infection is a debilitating and potentially life-threatening condition that affects the skin, underlying tissue, muscle, and fascia.

No high grade evidence is available for any of the interventions in NSTI, and adjunct therapies such as hyperbaric oxygen therapy remain controversial. Hyperbaric oxygen therapy has been used for nearly half a century to supplement traditional treatments for NSTI, but high-level clinical evidence has yet to be available.

The study therefore asks whether HBOT would still demonstrate beneficial results using data from the latest update to the National Inpatient Sample. The role of hyperbaric oxygen therapy in necrotizing soft tissue infections is mainly based on small retrospective studies.

A previous study using the 1998 to 2009 National Inpatient Sample found HBOT to be associated with decreased mortality in NSTI. Given the argument of advancements in critical care, the study investigated the continued role of HBOT in NSTI. The 2012 to 2020 National Inpatient Sample was queried for NSTI admissions who received surgery.

Sixty thousand four hundred eighty-one patients between 2012 and 2020 were included, and six hundred, fewer than one percent, underwent HBOT. The primary outcome was in-hospital mortality, while secondary outcomes included amputation, hospital length of stay, and costs.

A multivariate model was constructed to account for baseline differences between groups. Several subgroup analyses were completed using the same methods as the primary analysis. The analysis included a subset of patients who also presented with sepsis as coded in the National Inpatient Sample.

Separate analyses subdivided patients by NSTI site, truncal versus extremity, and causative pathogen, Clostridial versus non-Clostridial. Patients were stratified into those who received hyperbaric oxygen therapy and those who did not. Available data did not include HBOT duration, number of treatments, treatment pressure, or timing of treatments in relation to admission or surgery.

Patients who did not undergo surgical interventions or had missing key variables, including age, mortality, and costs, were excluded from the study; this represented one point two percent. Figure one traces the study population from eighty-nine thousand thirty-two National Inpatient Sample hospitalizations for necrotizing soft tissue infection between twenty-twelve and twenty-twenty.

It shows exclusions for patients younger than eighteen or with missing data, and for those without a surgical operation, leaving sixty thousand four hundred eighty-one surgically treated patients. This cohort was then stratified into no hyperbaric oxygen therapy, with fifty-nine thousand eight hundred eighty-one patients, and adjunct hyperbaric oxygen therapy, with six hundred.

Of sixty thousand four hundred eighty-one unweighted patients admitted with NSTI who underwent surgery, six hundred, fewer than one percent, received HBOT during admission. Both groups had similar ages, gender distribution, burden of comorbidities measured by ECI, incidence of acute kidney injury, and causative pathogens.

The HBOT group had a lower incidence of sepsis and urgent admissions than the control group, but a higher incidence of truncal NSTI and more private insurance. Patients undergoing HBOT had greater rates of chronic kidney disease, diabetes, and peripheral arterial disease.

Table one compares demographics and baseline characteristics for six hundred HBOT patients with fifty-nine thousand eight hundred eighty-one controls undergoing surgery for necrotizing soft tissue infection. Age, gender, Elixhauser Comorbidity Index, and acute kidney injury were similar, while the table reports differences in hospital location, income, insurance, chronic kidney disease, diabetes, sepsis, peripheral arterial disease, admission type, and NSTI site.

This baseline profile matters because these characteristics can shape comparisons of outcomes between treatment groups. On bivariate comparison, the control group had a higher incidence of mortality, five point nine percent versus less than two percent, and amputations, eighteen point three percent versus eleven point eight percent.

The HBOT group had significantly longer hospital stays, seventeen days versus fifteen days, and higher costs, fifty-four thousand dollars versus forty-six thousand dollars. Rates of non-home discharge were higher in the control group, forty-five point three percent versus forty-one percent.

Table two compares bivariate outcomes for six hundred HBOT patients and fifty-nine thousand eight hundred eighty-one controls undergoing surgery for necrotizing soft tissue infection. Mortality was at most ten, or less than zero point zero two percent, versus three thousand five hundred five, or five point nine percent; amputations were seventy-one, or eleven point eight percent, versus ten thousand nine hundred fifty-seven, or eighteen point three percent.

The table also reports longer stays and higher costs in the HBOT group, while non-home discharge was forty-one point zero versus forty-five point three percent; all listed overall comparisons have P values below zero point zero zero one. After adjusting for baseline differences, HBOT was associated with a lower risk of mortality, with an adjusted odds ratio of zero point two two, and a lower risk of amputation, with an adjusted odds ratio of zero point seven three.

Management of NSTI with HBOT was associated with longer hospital stays by one point six days and increased costs by seven thousand eight hundred dollars. Table three reports risk-adjusted outcomes for surgical patients with necrotizing soft tissue infection receiving hyperbaric oxygen therapy, using non-HBOT therapy as the reference.

It lists adjusted odds ratios or beta coefficients, with confidence intervals and p-values, across mortality, amputation, length of stay, cost, and discharge destinations. Notable estimates include zero point two two for mortality, seven point eight for cost, and zero point four seven for short-term hospital discharge, showing the range of outcomes examined after adjustment.

The sepsis subgroup included thirty-five thousand two hundred fifty-eight patients, of which two hundred ninety-five, fewer than one percent, received HBOT. After correcting for differences between groups, HBOT continued to be associated with significantly lower mortality, lower odds of amputations, and fewer non-home discharges.

In contrast to the primary analysis, after adjustments, neither length of stay nor cost was significantly different between groups. Table Four reports risk-adjusted outcomes for patients with sepsis undergoing surgery for necrotizing soft tissue infection, comparing HBOT with non-HBOT therapy.

HBOT is associated with an adjusted mortality odds ratio of zero point sixteen, with a ninety-five percent confidence interval from zero point zero six to zero point forty-six and a p-value below zero point zero zero one; amputation is reported at zero point forty-two, with a confidence interval from zero point twenty-eight to zero point sixty-two.

The table also reports discharge destinations, length of stay, and cost, showing why the sepsis-only analysis matters for assessing multiple clinical outcomes. On univariate analysis, HBOT was associated with decreased mortality in both truncal and extremity NSTI.

After adjusting for relevant confounders, this difference persisted in the group with NSTI of the extremity, with an adjusted odds ratio of zero point one nine. Despite improvements in critical and surgical care over the last decade, hyperbaric oxygen continued to be associated with significantly increased survivability in necrotizing soft tissue infections.

After adjustments for confounders, the addition of HBOT to surgery was associated with decreased mortality, decreased amputation rates, and more discharges to home. The apparent tradeoff was that HBOT was associated with longer total lengths of stay and slightly higher hospital costs.

In patients with sepsis, decreases in mortality, amputations, and non-home discharges persisted, without the increases in length of stay and cost. Within the subgroup of patients with NSTI and sepsis, the association with HBOT and decreased mortality, amputations, and non-home discharges persisted.

Within that subgroup, the signals for both longer length of stay and increased costs were no longer seen. The study has several limitations inherent to its nature as a large retrospective review of a national database. Temporal relations within specific hospitalizations are difficult to ascertain, including the timing of HBOT from presentation and the timing of surgery.

Data was not available regarding HBOT duration, treatment depth, number of treatments completed, or whether chambers were multiplace or monoplace. There is an inherent selection bias for HBOT administration depending on ICU resources, hyperbaric chamber availability, and hemodynamic stability.

The data does not include information on disease severity, such as sequential organ failure assessment score or hemodynamic parameters. In this national retrospective cohort, HBOT was associated with lower mortality, amputation, and non-home discharge, but with longer stays and higher costs overall.

Those associations persisted in patients with sepsis, without the added stay or cost.