Visual assessment of interactions among resuscitation activity factors in out-of-hospital cardiopulmonary arrest using a machine learning model.

AIM: The evaluation of the effects of resuscitation activity factors on the outcome of out-of-hospital cardiopulmonary arrest (OHCA) requires consideration of the interactions among these factors. To improve OHCA success rates, this study assessed the prognostic interactions resulting from simultaneously modifying two prehospital factors using a trained machine learning model. METHODS: We enrolled 8274 OHCA patients resuscitated by emergency medical services (EMS) in Nara prefecture, Japan, with a unified activity protocol between January 2010 and December 2018; patients younger than 18 and those with noncardiogenic cardiopulmonary arrest were excluded. Next, a three-layer neural network model was constructed to predict the cerebral performance category score of 1 or 2 at one month based on 24 features of prehospital EMS activity. Using this model, we evaluated the prognostic impact of continuously and simultaneously varying the transport time and the defibrillation or drug-administration time in the test data based on heatmaps. RESULTS: The average class sensitivity of the prognostic model was more than 0.86, with a full area under the receiver operating characteristics curve of 0.94 (95% confidence interval of 0.92-0.96). By adjusting the two time factors simultaneously, a nonlinear interaction was obtained between the two adjustments, instead of a linear prediction of the outcome. CONCLUSION: Modifications to the parameters using a machine-learning-based prognostic model indicated an interaction among the prognostic factors. These findings could be used to evaluate which factors should be prioritized to reduce time in the trained region of machine learning in order to improve EMS activities.

Association of multiple rib fractures with the frequency of pneumonia in the post-resuscitation period.

Purpose: Successful cardiopulmonary resuscitation is associated with a high incidence of chest wall injuries. However, few studies have examined chest wall injury as a risk factor for respiratory complications after cardiopulmonary resuscitation. Therefore, herein, we investigated the association of multiple rib fractures on the incidence of post-resuscitation pneumonia. Methods: This single-centre retrospective cohort study enrolled adult, nontraumatic, out-of-hospital cardiac arrest patients who maintained circulation for more than 48 h between June 2015 and May 2019. Rib fractures were evaluated by computed tomography on the day of hospital admission. The association with newly developed pneumonia within 7 days of hospitalisation was analysed using a Fine-Gray proportional hazards regression model adjusted for the propensity score of multiple rib fractures estimated from age, sex, presence of witnessed status, bystander CPR, initial rhythm, and total CPR time and for previously reported risk factors for pneumonia (therapeutic hypothermia and prophylactic antibiotics). Results: Overall, 683 patients with out-of-hospital cardiac arrest were treated; 87 eligible cases were enrolled for analysis. Thirty-two (36.8%) patients had multiple rib fractures identified on computed tomography, and 35 (40.2%) patients developed pneumonia. The presence of multiple rib fractures was significantly associated with a higher incidence of pneumonia, consistently both with and without adjustment for background factors (unadjusted hazard ratio 4.63, 95% confidence interval: 2.35-9.13, p < 0.001; adjusted hazard ratio 4.03, 95% confidence interval: 2.08-7.82, p < 0.001). Conclusions: Multiple rib fractures are independently associated with the development of pneumonia after successful resuscitation.

A new quantitative assessment method for predicting pneumonia caused by chest wall injury.

BACKGROUND: The severity of rib fractures has been previously evaluated by combining categorical data, but these methods have only low predictive capability for respiratory complications and mortality. This study aimed to establish a more accurate method for predicting the development of pneumonia, a frequent complication in chest injuries, using anatomical relationships. METHODS: We analyzed three-dimensional reconstructed images of 644 consecutive trauma patients who underwent whole-body computed tomography (CT) in our institution within a 36-month study period from April 2017. The anatomical relationship between the right and left thoracic volumes of non-rib fracture patients was used to estimate thoracic volume changes on the injured side in unilateral rib fracture patients. The predictive capability of changes in thoracic volume for the development of pneumonia was evaluated according to the area under the receiver operating characteristic curve and compared with that of previous chest wall severity evaluation methods. RESULTS: Of the 644 patients, 133 and 478 patients had unilateral rib fractures and non-rib fractures, respectively. The amount of change in thoracic volume due to unilateral rib fractures was significantly greater in pneumonia patients (400 mL vs. 160 mL, p < 0.01). The area under the receiver operating characteristic curve for the development of pneumonia was 0.83, which tended to be higher than that of the previous severity scoring methods. CONCLUSION: The amount of change in chest volume, which can be estimated using CT images, has better predictive capability for pneumonia than previous severity assessment methods based on categorical data. The amount of change in chest volume measured using whole-body CT can be used to rapidly determine the optimal treatment for severe chest wall injuries. LEVEL OF EVIDENCE: Prognostic study, level IV.

Periprosthetic tibial fracture after total knee arthroplasty with popliteal artery injury-A case report.

We present the case of a 79-year-old woman who presented at our center with a periprosthetic tibial fracture with a popliteal artery injury after total knee arthroplasty. Anastomosis of the popliteal artery was performed on the day of injury, and was later treated by open reduction and internal fixation. The patient was able to walk 3 months after injury. The present case was difficult to treat because of the arterial injury associated with periprosthetic fracture. Although revision of the implant was considered, open reduction and internal fixation was selected because of the severity of soft-tissue damage. The mechanism of injury is not uncommon, and it is expected that similar fractures will become more prevalent in the future as the number of knee replacement surgeries increases.

Minimally invasive spinopelvic "crab-shaped fixation" for unstable pelvic ring fractures: technical note and 16 case series.

BACKGROUND: Unstable sacral fractures are high-energy injuries and comprise polytrauma. Internal fixation to enable withstanding vertical loads is required to get up early from the bed after an unstable sacral fracture. We developed a new minimally invasive surgical (MIS) procedure for unstable pelvic ring fractures and reported it in Japanese in 2010. We presented our minimally invasive surgical technique of crab-shaped fixation for the treatment of unstable pelvic ring fractures and report on its short-term outcomes. METHODS: Sixteen patients with unstable pelvic ring fractures (AO types C1, 2, and 3) were treated using crab-shaped fixation. All procedures were performed with the patient in the prone position through 5-cm skin incisions created bilaterally at the level of the posterior superior iliac spine. Four iliac screws were inserted and connected with two rods under the fascia. Percutaneous pedicle screws were inserted at L5 or L4 and connected to the iliac rod using offset connectors. Fracture reduction was then performed. RESULTS: The average surgical time was 158 min (range, 117-230 min), with an intraoperative bleeding volume of 299 ml (range, 80-480 ml). Thirty-three pedicle screws and 64 iliac screws were implanted with no instance of malpositioning or perforation. A surgical site infection developed in 2 of the 16 cases. Both were deep methicillin-resistant Staphylococcus aureus infections, with the removal of the distal implants required in only one of these cases. Bony union was achieved in all patients, and all vertical displacements reduced by 7.0 mm, on average (range, 5.4-9.0 mm), to < 10 cm. Correction was retained in all cases. CONCLUSIONS: Crab-shaped fixation provides a feasible MIS approach for spinopelvic fixation, which allows good reduction of the vertical displacement of unstable pelvic ring fractures and bony union.

Von Willebrand Factor Aggravates Hepatic Ischemia-Reperfusion Injury by Promoting Neutrophil Recruitment in Mice.

Hepatic ischaemia-reperfusion (I/R) injury is a serious liver damage that critically influences the clinical outcome of liver surgery or transplantation. Since recent studies indicated the critical involvement of von Willebrand factor (VWF) in reperfusion injuries of brain and myocardium, we hypothesized that VWF-dependent thrombotic or inflammatory responses also play a role in hepatic I/R injury. Using a mouse model of hepatic I/R injury, we explored the functional relevance of the VWF-ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) axis in this pathologic condition. Time-course studies during hepatic I/R revealed significantly lower alanine aminotransferase (ALT) values, as well as greater hepatic blood flow, in VWF gene-deleted (KO) mice in comparison with wild-type (WT) mice. Histological analysis revealed a significantly lesser extent of neutrophil infiltration and hepatocellular necrosis in liver tissues of VWF-KO mice. Human recombinant ADAMTS13 significantly improved the impairment in ALT values and hepatic blood flow and decreased neutrophil infiltration within the liver tissue of WT mice. Real-time intravital imaging successfully visualized significantly reduced leukocyte-vessel wall interactions in I/R liver of VWF-KO mice. Taken together, our results indicate that VWF promotes neutrophil recruitment in ischaemic mouse liver, critically aggravating reperfusion injury, and suggest that functional regulation of VWF by ADAMTS13 represents a promising therapeutic option for hepatic I/R injury.

Performance review of regional emergency medical service pre-arrival cardiopulmonary resuscitation with or without dispatcher instruction: a population-based observational study.

Background: To investigate variations in emergency medical service (EMS) pre-arrival cardiopulmonary resuscitation (CPR), including both bystander CPR without dispatch assistance and dispatch-assisted CPR (DACPR). Methods: We carried out an observational study by implementing EMS pre-arrival CPR reports in three fire agencies. We included adult, non-traumatic, and non-EMS witnessed out-of-hospital cardiac arrests. This reporting system comprised the dispatch instruction process and bystander CPR quality based on evaluations by EMS crews who arrived on the scene. Bystander CPR was categorized as "ongoing CPR" if the bystander was performing CPR when the EMS reached the patient's side and "good-quality CPR" if the CPR was performed proficiently. We compared the frequencies of ongoing and good-quality CPR in the bystander CPR already started without dispatch assistance (CPR in progress) group and DACPR group. Results: Of 688 out-of-hospital cardiac arrests, CPR was already started in 150 cases (CPR in progress group). Dispatcher CPR instruction was provided in 368 cases. Among these, callers started chest compressions in 162 cases (DACPR group). Ongoing CPR was performed in 220 cases and was more frequent in the DACPR group (128/162 [79.0%] versus 92/150 [61.3%], P < 0.001). Good-quality CPR was more frequent in the CPR in progress group, but the difference was not statistically significant (36/92 [39.1%] versus 42/128 [29.0%], P = 0.888). Conclusions: Ongoing CPR and good-quality CPR were not frequent in EMS pre-arrival CPR. Detailed analysis of dispatch instructions and bystander CPR can contribute to improvement in EMS pre-arrival CPR.

Implementation of a dispatch-instruction protocol for cardiopulmonary resuscitation according to various abnormal breathing patterns: a population-based study.

BACKGROUND: We modified the dispatch protocol for cardiopulmonary resuscitation (CPR) using results of a retrospective analysis that identified descriptions by laypersons of possible patterns of agonal respiration. The purpose of this study was to assess the effectiveness of this modified protocol by comparing the frequency of dispatch instructions for CPR and bystander CPR before and after protocol implementation. We also identified descriptions of abnormal breathing patterns among 'Not in cardiac arrest (CA)' unresponsive cases. METHODS: This study was conducted prospectively using the population-based registry of out-of-hospital cardiac arrests (OHCAs). For 8 months we implemented this modified protocol in cooperation with 4 fire departments that cover regions with a total population of 840,000. RESULTS: There were 478 and 427 OHCAs before and after implementation, respectively. Among them, 69 and 71 layperson-witnessed OHCAs for pre- and post-implementation, respectively, were analyzed. Dispatchers provided CPR instructions more frequently after protocol implementation than before (55/71 [77.5 %] vs. 41/69 [59.4 %], p < 0.05). Based on breathing patterns described by emergency callers, dispatchers assessed 143 'Not in CA' unresponsive cases and provided CPR instruction for 45 cases. Sensitivity and specificity of this protocol was 93 % and 50 %, respectively. CONCLUSIONS: This modified protocol based on abnormal breathing described by laypersons significantly increased CPR instructions. Considering high sensitivity and low specificity for abnormal breathing to identify CA and the low risk of chest compression for 'Not in CA' cases, our study suggested that dispatchers can provide CPR instruction assertively and safely for those unresponsive individuals with various abnormal breathing patterns.

Abnormal breathing of sudden cardiac arrest victims described by laypersons and its association with emergency medical service dispatcher-assisted cardiopulmonary resuscitation instruction.

BACKGROUND: Current guidelines for cardiopulmonary resuscitation (CPR) emphasise that emergency medical service (EMS) dispatchers should identify sudden cardiac arrest (CA) with abnormal breathing and assist lay rescuers performing CPR. However, lay rescuers description of abnormal breathing may be inconsistent, and it is unclear how EMS dispatchers provide instruction for CPR based on the breathing status of the CA victims described by laypersons. METHODS AND RESULTS: To investigate the incidence of abnormal breathing and the association between the EMS dispatcher-assisted CPR instruction and layperson CPR, we retrospectively analysed 283 witnessed CA cases whose information regarding breathing status of CA victims was available from population-based prospective cohort data. In 169 cases (59.7%), laypersons described that the CA victims were breathing in various ways, and that the victims were 'not breathing' in 114 cases (40.3%). Victims described as breathing in various ways were provided EMS dispatch-instruction for CPR less frequently than victims described as 'not breathing' (27.8% (47/169) vs 84.2% (96/114); p<0.001). Multivariate logistic regression showed that EMS dispatch-instruction for CPR was associated significantly with layperson CPR (adjusted OR, 11.0; 95% CI, 5.72 to 21.2). CONCLUSIONS: This population-based study indicates that 60% of CA victims showed agonal respiration, which was described as breathing in various ways at the time of EMS call. Although EMS dispatch-instruction was associated significantly with an increase in layperson CPR, abnormal breathing was associated with a much lower rate of CPR instruction and, in turn, was related to a much lower rate of bystander CPR.

A case of emphysematous cystitis diagnosed by exploratory laparotomy.

Emphysematous cystitis is a rare form of infection. Well known symptoms are: dysuria, urinary frequency and lower abdominal pain. We experienced a case of emphysematous cystitis presented with atypical peritoneal sign and computed tomography findings of massive intra-peritoneal fluid collection and abnormal gas appearance in pelvic space. Due to its presentation as acute abdomen, patient underwent exploratory laparotomy and the diagnosis of emphysematous cystitis was established. As far as we know, our case is the first report of emphysematous cystitis with intra-peritoneal fluid collection.