伊澤 祥光

BACKGROUND: Traumatic diaphragmatic injury (TDI) is well-known worldwide as rare and life-threatening. However, because no nationwide cohort study of penetrating and blunt TDI has been conducted in Japan and other countries where penetrating trauma is relatively uncommon, the clinical characteristics of all TDI are unknown. We aimed to describe the characteristics of TDI patients, compare penetrating TDI with blunt TDI, and identify mortality risk factors in Japan. METHODS: We retrospectively identified TDI patients between 2004 and 2019 using data from the Japan Trauma Data Bank. We extracted data on patient demographics, type of trauma, cause of trauma, physiological parameters, region of concomitant injury, associated injury, and management. We compared penetrating and blunt TDI for each variable. The primary outcome was mortality. Multivariable logistic regression was performed to identify mortality risk factors. RESULTS: Of the 338,744 patients, 1,147 (0.3%) had TDI, of which 771 were eligible for analysis (excluding 308 in cardiac arrest on arrival). Penetrating TDI represented 29.8% and blunt TDI 70.2%, and comparing penetrating and blunt TDI, the most common cause was self-inflicted (48.7%) vs. accident (85.6%), males were 68.7% vs. 66.0% of the patients (P = 0.50), and the mortality rate was 8.3% vs. 26.4% (P < 0.001). Multivariable analysis found that age (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.01-1.04), Injury Severity Score (OR 1.03, 95%CI 1.006-1.06), Revised Trauma Score (OR 0.55, 95%CI 0.45-0.67), severe concomitant abdominal injury (OR 2.45, 95%CI 1.32-4.56), severe concomitant upper extremity injury (OR 3.38, 95%CI 1.24-9.17) were independent predictors of mortality, and computed tomography (CT) (OR 0.32, 95%CI 0.15-0.69) and diaphragm repair (OR 0.44, 95%CI 0.25-0.78) were protective factors. CONCLUSIONS: In Japan, we found that penetrating TDI was mainly caused by self-injury and the male-female ratio was the same as for blunt TDI, although blunt TDI was much more frequent. TDI was considered highly lethal, with over 25% of patients in cardiac arrest on arrival. Our unique independent predictors were CT, severe concomitant abdominal injury, and severe concomitant upper extremity injury. These findings may help in the management of TDI in countries with less common penetrating trauma.

BACKGROUND Inferior vena cava (IVC) injury is a potentially fatal injury with a high mortality rate of 34-70%. In cases in which the patient's condition is stable, diagnosis by computed tomography (CT) is the criterion standard. Findings on CT include retroperitoneal hematoma around the IVC, extravasation of contrast medium, and abnormal morphology of the IVC. We report a case of an IVC injury that could not be diagnosed by preoperative CT examination and could not be immediately detected during laparotomy. CASE REPORT A 73-year-old woman had stabbed herself in the neck and abdomen at home using a knife. When she arrived at our hospital, we found a stab wound several centimeters long on her abdomen and a cut approximately 15 cm long on her neck. We activated the massive transfusion protocol because she was in a condition of hemorrhagic shock. After blood transfusion and blood pressure stabilization, contrast-enhanced computed tomography (CT) revealed a small amount of fluid in the abdominal cavity. An otorhinolaryngologist performed successful drainage and hemostasis, and a laparotomy was performed. Gastric injury and mesentery injury of the transverse colon were identified and repaired with sutures. Subsequent search of the retroperitoneum revealed massive bleeding from an injury to the inferior vena cava (IVC). The IVC was repaired. Postoperative progress was good, and she was discharged from the hospital 65 days after her injuries. CONCLUSIONS We experienced a case of penetrating IVC injury, which is a rare trauma. Occult IVC injury may escape detection by preoperative CT examination or during laparotomy.

BACKGROUND: In recent years, various home-use health devices have gained popularity. The abdominal roller is one of these. Spinal cord injury without radiological abnormality is known to occur even with relatively minor injuries, but there are few reports of such injuries caused by a roller. CASE PRESENTATION: Two cases of spinal cord injuries caused by a roller are reported. In both cases, injuries occurred during the standing rollout by a patient in an inebriated state, and the patients were rushed to an emergency department. CONCLUSION: Because the use of abdominal rollers may result in extremely serious disabilities, it is necessary to emphasize the appropriate use of such equipment.

Blast injuries caused by an improvised explosive device (IED) are becoming more common in civilian settings. However, physicians may not be familiar with the treatment and management of blast-injured victims. To the best of our knowledge, this is the first case report of a blast injury caused by an IED in Japan. A 64-year-old man was admitted to our hospital's emergency department after sustaining a blast injury. His vital signs were stable, but he had multiple small wounds with embedded foreign bodies that were consistent with injuries sustained by IED victims. The patient was treated for his injuries and was moved to another hospital on day 37. Knowledge about blast injuries caused by IEDs and management strategies for mass casualties are both necessary.

BACKGROUND Centipede envenomation is usually mild, but a review of the existing literature revealed a more serious course in a small proportion of patients. In fact, necrotizing soft-tissue infections have been reported following centipede stings in a small number of cases and require early diagnosis and treatment because of a high mortality rate. CASE REPORT A 78-year-old man was stung by a centipede on the left abdomen. Treatment with antimicrobial agents was started due to cellulitis, but extensive erythema developed from the left chest to the left buttock. Six days after being stung, he visited our hospital. Necrotizing soft-tissue infection was diagnosed and treated immediately with antibiotics and debridement on the left side of the abdomen and chest. Group A Streptococcus was detected in the fascia. The wound was left partially open and washed daily, resulting in gradual improvement of the wound condition. On hospitalization day 8, the open wound was able to be closed. Antimicrobial therapy was completed on hospitalization day 16. The patient showed good progress. CONCLUSIONS Centipede stings are not rare in tropical and subtropical regions, and most occurrences of centipede envenomation cause only local symptoms. However, we believe that even wounds caused by centipedes should be monitored, given the possibility of subsequent severe infection, as in the present case. In addition, the causative organisms identified in the present patient with necrotizing soft-tissue infection following a centipede sting were commensal bacteria of the skin. Future research is thus needed to clarify the relationship between these causative organisms and centipedes.

50歳代男性。トラックを運転中, 停車していたトラックに追突して受傷した。精査のComputed tomography (CT) にて両側外傷性気胸・骨盤骨折に加えて左総頸動脈の造影途絶を認めた。左内頸動脈および左外頸動脈は造影されていた。頭蓋内に梗塞所見はないため慎重に経過観察していたが, 来院14時間後に右片麻痺と意識レベルの低下が出現した。magnetic resonance imaging (MRI) で左中大脳動脈領域の脳梗塞を認めた。骨盤骨折の手術後から抗凝固療法を開始した。失語と麻痺は残存したが神経症状は増悪なく経過し, 約2カ月後に転院した。鈍的外傷による総頸動脈閉塞はまれな疾患であるが, 神経症状出現率・死亡率がともに高率である。治療として抗血小板薬の有用性が報告されているが, 多発外傷の患者においては出血増悪によるリスクも加味する必要があり, 治療には今後さらなる検討が必要と考えられた。

BACKGROUND: Unnecessary whole-body computed tomography (CT) may lead to excess radiation exposure. Serum D-dimer levels have been reported to correlate with injury severity. We examined the predictive value of serum D-dimer level for identifying patients with isolated injury that can be diagnosed with selected-region CT rather than whole-body CT. METHODS: This single-center retrospective cohort study included patients with blunt trauma (2014-2017). We included patients whose serum D-dimer levels were measured before they underwent whole-body CT. "Isolated" injury was defined as injury with Abbreviated Injury Scale (AIS) score ≤ 5 to any of five regions of interest or with AIS score ≤ 1 to other regions, as revealed by a CT scan. A receiver operating characteristic curve (ROC) was drawn for D-dimer levels corresponding to isolated injury; the area under the ROC (AUROC) was evaluated. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for several candidate cut-off values for serum D-dimer levels. RESULTS: Isolated injury was detected in 212 patients. AUROC was 0.861 (95% confidence interval [CI]: 0.815-0.907) for isolated injury prediction. Serum D-dimer level ≤ 2.5 μg/mL was an optimal cutoff value for predicting isolated injury with high specificity (100.0%) and positive predictive value (100.0%). Approximately 30% of patients had serum D-dimer levels below this cutoff value. CONCLUSION: D-dimer level ≤ 2.5 μg/mL had high specificity and high positive predictive value in cases of isolated injury, which could be diagnosed with selected-region CT, reducing exposure to radiation associated with whole-body CT.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) increases proximal pressure, and simultaneously induces distal ischemia. We aimed to evaluate organ ischemia during partial REBOA (P-REBOA) with computed tomography (CT) perfusion in a swine model. The maximum balloon volume was recorded as total REBOA when the distal pulse pressure ceased. The animals (n = 4) were scanned at each 20% of the maximum balloon volume, and time-density curve (TDC) were analysed at the aorta, portal vein (PV), liver parenchyma, and superior mesenteric vein (SMV, indicating mesenteric perfusion). The area under the TDC (AUTDC), the time to peak (TTP), and four-dimensional volume-rendering images (4D-VR) were evaluated. The TDC of the both upper and lower aorta showed an increased peak and delayed TTP. The TDC of the PV, liver, and SMV showed a decreased peak and delayed TTP. The dynamic 4D-CT analysis suggested that organ perfusion changes according to balloon volume. The AUTDC at the PV, liver, and SMV decreased linearly with balloon inflation percentage to the maximum volume. 4D-VR demonstrated the delay of the washout in the aorta and retrograde flow at the inferior vena cava in the highly occluded status.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a viable resuscitation approach for a subdiaphragmatic injury that can regulate arterial blood flow. On the other hand, the evaluation of venous or portal venous blood flow during REBOA remains insufficient because invasive cannulation or exposure of the vessel may affect the blood flow, and Doppler echography is highly operator-dependent. However, phase contrast magnetic resonance imaging has enabled accurate evaluation and noninvasive measurement. This study aimed to investigate the change of venous and portal venous blood flow during REBOA in a porcine model. METHODS: Seven pigs were anesthetized, and a REBOA catheter was placed. The blood flows of the inferior vena cava (IVC), hepatic vein (HV), portal vein (PV), and superior vena cava (SVC) were measured using phase contrast magnetic resonance imaging, in both the balloon deflated (no-REBOA) and fully balloon inflated (REBOA) states. Mean arterial pressure (MAP), central venous pressure, cardiac index, and systemic vascular resistance index were measured. RESULTS: The blood flows of the suprahepatic, infrahepatic, and distal IVC, HV, and PV in the no-REBOA state were 1.40 ± 0.36 L·min, 0.94 ± 0.16 L·min, 0.50 ± 0.19 L·min, 0.060 ± 0.018 L·min, and 0.32 ± 0.091 L·min, respectively. The blood flow of each section in the REBOA condition was significantly decreased at 0.41 ± 0.078 (33% of baseline), 0.15 ± 0.13 (15%), 0.043 ± 0.034 (9%), 0.029 ± 0.017 (37%), and 0.070 ± 0.034 L·min (21%), respectively. The blood flow of the SVC increased significantly in the REBOA condition (1.4 ± 0.63 L·min vs. 0.53 ± 0.14 L·min [257%]). Mean arterial pressure, central venous pressure, cardiac index, and systemic vascular resistance index were significantly increased after REBOA inflation. CONCLUSION: Resuscitative endovascular balloon occlusion of the aorta decreased blood flows of the IVC, HV, and PV and increased blood flow of the SVC. This result could be explained by the collateral flow from the lower body to the SVC. A better understanding of the effect of REBOA on the venous and portal venous systems may help control liver injury.