Statistical Power of Randomized Controlled Trials in Trauma Surgery

BACKGROUND

Our purpose was to conduct a bibliometric study investigating the prevalence of underpowered randomized controlled trials (RCTs) in trauma surgery.

STUDY DESIGN

A medical librarian conducted a search of RCTs in trauma published from 2000 to 2021. Data extracted included study type, sample size calculation, and power analyses. Post hoc calculations were performed using a power of 80% and an alpha level of 0.05. A CONSORT checklist was then tabulated from each study as well as a fragility index for studies with statistical significance.

RESULTS

In total 187 RCTs from multiple continents and 60 journals were examined. A total of 133 (71%) were found to have "positive" findings consistent with their hypothesis. When evaluating their methods, 51.3% of articles did not report how they calculated their intended sample size. Of those that did, 25 (27%) did not meet their target enrollment. When examining post hoc power, 46%, 57%, and 65% were adequately powered to detect small, medium, and large effect sizes, respectively. Only 11% of RCTs had complete adherence with CONSORT reporting guidelines and the average CONSORT score was 19 out of 25. For positive superiority trials with binary outcomes, the fragility index median (interquartile range) was 2 (2 to 8).

CONCLUSIONS

A concerningly large proportion of recently published RCTs in trauma surgery do not report a priori sample size calculations, do not meet enrollment targets, and are not adequately powered to detect even large effect sizes. There exists opportunity for improvement of trauma surgery study design, conduct, and reporting.

The effect of mesenchymal stem cells improves the healing of burn wounds: a phase 1 dose-escalation clinical trial

Background

Stem cell therapy holds promise to improve healing and stimulate tissue regeneration after burn injury. Preclinical evidence has supported this; however, clinical studies are lacking. We examined the application of bone marrow-derived mesenchymal stem cells (BM-MSC) to deep second-degree burn injuries using a two-dose escalation protocol.

Methods

Ten individuals aged 18 years or older with deep second-degree burn wounds were enrolled. The first five patients were administered 2.5 × 10³ BM-MSC/cm² to their wounds. After safety of the initial dose level was assessed, a second group of five patients was treated with a higher concentration of 5 × 10³ allogeneic BM-MSC/cm². Safety was assessed clinically and by evaluating cytokine levels in mixed recipient lymphocyte/donor BM-MSC reactions (INFγ, IL-10 and TNFα). At each visit, we performed wound measurements and assessed wounds using a Patient and Observer Scar Assessment Scale (POSAS).

Results

All patients responded well to treatment, with 100% closure of wounds and minimal clinical evidence of fibrosis. No adverse reactions or evidence of rejection were observed for both dose levels. Patients receiving the first dose concentration had a wound closure rate of 3.64 cm²/day. Patients receiving the second dose concentration demonstrated a wound closure rate of 10.47 cm²/day. The difference in healing rates between the two groups was not found to be statistically significant (P = 0.17).

Conclusion

BM-MSC appear beneficial in optimising wound healing in patients with deep second-degree burn wounds. Adverse outcomes were not observed when administering multiple doses of allogeneic BM-MSC.

Lay Summary

Thermal injuries are a significant source of morbidity and mortality, constituting 5%–20% of all injuries and 4% of all deaths. Despite overall improvements in the management of acutely burned patients, morbidities associated with deeper burn injuries remain commonplace. Burn patients are too often left with significant tissue loss, scarring and contractions leading to physical loss of function and long-lasting psychological and emotional impacts.

In previous studies, we have demonstrated the safety and efficacy of administering bone marrow-derived mesenchymal stem cells (BM-MSC) to chronic wounds with substantial improvement in healing and evidence of tissue regeneration. In this report, we have examined the application of BM-MSC to deep second-degree burn injuries in patients.

The aim of the present phase I/II clinical trial was to examine the safety and efficacy of administering allogeneic BM-MSC to deep second-degree burns. We utilised two different dose levels at concentrations 2.5 × 10³ and 5 × 10³ cells/cm². Patients with deep second-degree burn wounds up to 20% of the total body surface area were eligible for treatment. Allogeneic BM-MSC were applied to burn wounds topically or by injection under transparent film dressing <7 days after injury. Patients were followed for at least six months after treatment.

Using two dose levels allowed us to gain preliminary information as to whether different amounts of BM-MSC administered to burn wounds will result in significant differences in safety/ clinical response. Once the safety and dose-response analysis were completed, we evaluated the efficacy of allogeneic stem cell therapy in the treatment of deep second-degree burn wounds.

In this study, we examined the role of allogeneic BM-MSC treatment in patients with deep second-degree burn injuries, in a dose-dependent manner. No significant related adverse events were reported. Safety was evaluated both clinically and by laboratory-based methods. Efficacy was assessed clinically through evidence of re-pigmentation, hair follicle restoration and regenerative change. While these findings are encouraging, more studies will be needed to better establish the benefit of BM-MSC in the treatment of burn injuries.

Environmental Exposure to Carbapenem-Resistant Acinetobacter baumannii as a Risk Factor for Patient Acquisition of A. baumannii

We aimed to determine the association between environmental exposure to carbapenem-resistant Acinetobacter baumannii and the subsequent risk of acquiring this organism. Patients exposed to a contaminated hospital environment had 2.77 times the risk of acquiring carbapenem-resistant A. baumannii than did unexposed patients (relative risk, 2.77 [95% confidence interval, 1.50–5.13]; P = .002).

Control of a two-decade endemic situation with carbapenem-resistant Acinetobacter baumannii: electronic dissemination of a bundle of interventions

BACKGROUND

Our institution continued to experience a hyperendemic situation with carbapenem-resistant Acinetobacter baumannii despite a bundle of interventions. We aim to describe the effect of the subsequent implementation of electronic dissemination of the weekly findings of a bundle of interventions.

METHODS

This was a quasiexperimental study performed at a 1,500-bed, public, teaching hospital. From January 2011 to March 2012, weekly electronic communications were sent to the hospital leadership and intensive care units (ICUs). These communications aimed to describe, interpret, and package the findings of the previous week's active surveillance cultures, environmental cultures, environmental disinfection, and hand cultures. Additionally, action plans based on these findings were shared with recipients.

RESULTS

During 42 months and 1,103,900 patient-days, we detected 438 new acquisitions of carbapenem-resistant A baumannii. Hospital wide, the rate of acquisition decreased from 5.13 ± 0.39 to 1.93 ± 0.23 per 10,000 patient-days, during the baseline and postintervention periods, respectively (P < .0001). This effect was also observed in the medical and trauma ICUs, with decreased rates from 67.15 ± 10.56 to 17.4 ± 4.6 (P < .0001) and from 55.9 ± 8.95 to 14.71 ± 4.45 (P = .0004), respectively.

CONCLUSION

Weekly and systematic dissemination of the findings of a bundle of interventions was successful in decreasing the rates of carbapenem-resistant A baumannii across a large public hospital.

Incidence of hepatic dysfunction is equivalent in burn patients receiving oxandrolone and controls

Oxandrolone has been shown to improve lean muscle mass in patients with burns. Hepatic dysfunction is a known side effect of treatment with oxandrolone. The purpose of this study was to examine the incidence of hepatic dysfunction in our series of burn patients receiving oxandrolone. Fourteen patients who received oxandrolone (5 mg, n = 8; 10 mg, n = 6) were identified from our prospectively collected burn database. The records of 61 control patients also were reviewed. Demographics such as age, comorbidities, and burn size were recorded. The incidence of hepatic dysfunction was determined by the presence of abnormal liver function tests. The study and control groups were similar in age and burn size. Two of the eight (25%) oxandrolone patients receiving 5 mg and four of the six (67%) oxandrolone patients receiving 10 mg had evidence of hepatic dysfunction. Twenty six of the 61 (43%) control patients had evidence of hepatic dysfunction (P = NS). There appears no significant increased incidence of hepatic dysfunction in burn patients who received oxandrolone compared to those who did not.

Occult Pneumothorax in Trauma Patients: Development of an Objective Scoring System

BACKGROUND

The incidence of occult pneumothorax (OPTX) has dramatically increased since the widespread use of computed tomography (CT) scanning. The OPTX is defined as a pneumothorax not identified on plain chest X-ray but detected by CT scan. The overall reported incidence is about 5% to 8% of all trauma patients. We conducted a 5-year review of our OPTX incidence and asked if an objective score could be developed to better quantify the OPTX. This in turn may guide the practitioner with the decision to observe these patients.

METHODS

This is a retrospective review of all trauma patients in a Level I university trauma center during a 5-year period. The patients were identified by a query of all pneumothoraces in our trauma registry. Those X-ray results were then reviewed to identify those who had OPTX. After developing an OPTX score on a small number, we retrospectively scored 50 of the OPTXs by taking the largest perpendicular distance in millimeters from the chest wall of the largest air pocket. We then added 10 or 20 to this if the OPTX was either anterior/posterior or lateral, respectively.

RESULTS

A total of 21,193 trauma patients were evaluated and 1,295 patients with pneumothoraces (6.1%) were identified. Of the 1,295 patients with pneumothoraces, 379 (29.5%) OPTXs were identified. The overall incidence of OPTX was 1.8%: 95.7% occurred after blunt trauma, 222 (59%) of the OPTX patients had chest tubes and of the remaining 157 without chest tubes, 27 (17%) were on positive pressure ventilation. Of the 50 studies selected for scoring, the average score was 28.5. The average score for those with chest tubes was 34. The average score for those without chest tubes was 21. The positive predictive value for need of chest tube if the score was >30 was 78% and the negative predictive value if the score was <20 was 70%. Area under the receiver operator characteristic curve was 0.72, which was significant with p < 0.007.

CONCLUSIONS

The OPTX score could quantify the size of the OPTX allowing the practitioner to better define a "small" pneumothorax. The management of OPTX is not standardized and further study using a more objective classification may assist the surgeon's decision-making. The application of a scoring system may also decrease unnecessary insertion of chest tubes for small OPTXs and is currently being prospectively validated.

The nonoperative management of penetrating internal jugular vein injury

OBJECTIVE

The objective of this study was to review the outcome of nonoperative treatment for penetrating internal jugular vein (IJ) injuries in a continuous series of prospectively identified, hemodynamically stable patients.

METHODS

All penetrating neck injuries assessed from February 1, 2004, to August 31, 2004, were prospectively identified. Patients without an indication for urgent neck exploration underwent diagnostic assessment with multislice helical computed tomographic angiography with or without vascular ultrasonography. All IJ injuries with no other indication for surgical exploration were treated nonoperatively. All patients were discharged home and followed up for a minimum of 1 week to document outcomes.

RESULTS

From 51 neck injuries penetrating the platysma, 7 required urgent neck exploration, during which 2 IJ injuries were ligated. Forty-four patients underwent multislice helical computed tomographic angiography. Eight IJ injuries (two gunshot wounds and six stab wounds) with no other indication for neck exploration were identified and managed nonoperatively. One external wound was in zone 1, five were in zone 2, one was in zone 3, and one traversed all three zones. The average length of stay was 4.5 days. At follow-up, ranging from 1 week to 5 months, all patients were asymptomatic, and no patient required delayed operation for IJ injury.

CONCLUSIONS

In hemodynamically stable patients with no other indication for exploration, the nonoperative management of penetrating jugular vein injuries should be considered as a safe alternative.

A burn mass casualty event due to boiler room explosion on a cruise ship: preparedness and outcomes

The purpose of this study was to review our experience with a mass casualty incident resulting from a boiler room steam explosion aboard a cruise ship. Experience with major, moderate, and minor burns, steam inhalation, mass casualty response systems, and psychological sequelae will be discussed. Fifteen cruise ship employees were brought to the burn center after a boiler room explosion on a cruise ship. Eleven were triaged to the trauma resuscitation area and four to the surgical emergency room. Seven patients were intubated for respiratory distress or airway protection. Six patients had >80 per cent burns with steam inhalation, and all of these died. One of the 6 patients had 99 per cent burns with steam inhalation and died after withdrawal of support within the first several hours. All patients with major burns required escharotomy on arrival to trauma resuscitation. One patient died in the operating room, despite decompression by laparotomy for abdominal compartment syndrome and pericardiotomy via thoracotomy for cardiac tamponade. Four patients required crystalloid, 20,000 mls/m2-27,000 ml/m2 body surface area (BSA) in the first 48 hours to maintain blood pressure and urine output. Three of these four patients subsequently developed abdominal compartment syndrome and died in the first few days. The fourth patient of this group died after 26 days due to sepsis. Five patients had 13-20 per cent bums and four patients had less than 10 per cent burns. Two of the patients with 20 per cent burns developed edema of the vocal cords with mild hoarseness. They improved and recovered without intubation. The facility was prepared for the mass casualty event; having just completed a mass casualty drill several days earlier. Twenty-six beds were made available in 50 minutes for anticipated casualties. Fifteen physicians reported immediately to the trauma resuscitation area to assist in initial stabilization. The event occurred at shift change; thus, adequate support personnel were instantaneously to hand. Our mass casualty preparation proved useful in managing this event. Most of the patients who survived showed signs of post-traumatic stress syndrome, which was diagnosed and treated by the burn center psychology team. Despite our efforts at treating large burns (>80%) with steam inhalation, mortality was 100 per cent. Fluid requirements far exceeded those predicted by the Parkland (Baxter) formula. Abdominal compartment syndrome proved to be a significant complication of this fluid resuscitation. A coordinated effort by the facility and preparation for mass casualty events are needed to respond to such events.

A Burn Mass Casualty Event Due to Boiler Room Explosion on a Cruise Ship: Preparedness and Outcomes

The purpose of this study was to review our experience with a mass casualty incident resulting from a boiler room steam explosion aboard a cruise ship. Experience with major, moderate, and minor burns, steam inhalation, mass casualty response systems, and psychological sequelae will be discussed. Fifteen cruise ship employees were brought to the burn center after a boiler room explosion on a cruise ship. Eleven were triaged to the trauma resuscitation area and four to the surgical emergency room. Seven patients were intubated for respiratory distress or airway protection. Six patients had >80 per cent burns with steam inhalation, and all of these died. One of the 6 patients had 99 per cent burns with steam inhalation and died after withdrawal of support within the first several hours. All patients with major burns required escharotomy on arrival to trauma resuscitation. One patient died in the operating room, despite decompression by laparotomy for abdominal compartment syndrome and pericardiotomy via thoracotomy for cardiac tamponade. Four patients required crystalloid, 20,000 mls/m2–27,000 ml/m2 body surface area (BSA) in the first 48 hours to maintain blood pressure and urine output. Three of these four patients subsequently developed abdominal compartment syndrome and died in the first few days. The fourth patient of this group died after 26 days due to sepsis. Five patients had 13–20 per cent burns and four patients had less than 10 per cent burns. Two of the patients with 20 per cent burns developed edema of the vocal cords with mild hoarseness. They improved and recovered without intubation. The facility was prepared for the mass casualty event, having just completed a mass casualty drill several days earlier. Twenty-six beds were made available in 50 minutes for anticipated casualties. Fifteen physicians reported immediately to the trauma resuscitation area to assist in initial stabilization. The event occurred at shift change; thus, adequate support personnel were instantaneously to hand. Our mass casualty preparation proved useful in managing this event. Most of the patients who survived showed signs of post-traumatic stress syndrome, which was diagnosed and treated by the burn center psychology team. Despite our efforts at treating large burns (>80%) with steam inhalation, mortality was 100 per cent. Fluid requirements far exceeded those predicted by the Parkland (Baxter) formula. Abdominal compartment syndrome proved to be a significant complication of this fluid resuscitation. A coordinated effort by the facility and preparation for mass casualty events are needed to respond to such events.