Physiologic Derangements Research Articles

Understanding Preventable Deaths in the Geriatric Trauma Population: Analysis of 3,452,339 Patients From the Center of Medicare and Medicaid Services Database.

Patient safety indicators (PSIs) are avoidable complications that can impact outcomes. Geriatric patients have a higher mortality than younger patients with similar injuries, and understanding the etiology may help reduce mortality. We aim to estimate preventable geriatric trauma mortality in the United States and identify PSIs associated with increased preventable mortality. A retrospective cohort study of patients aged ≥65 years, in the CMS database, 2017-second quarter of 2020. Risk-adjusted multivariable regression was performed to calculate observed-to-expected (O/E) mortality ratios for failure-to-prevent and failure-to-rescue PSIs with significance defined as P < .05. 3 452 339 geriatric patients were analyzed. Patients aged 75-84 years had 33% higher odds of preventable mortality (adjusted odds ratio [aOR] = 1.33 and 95% confidence interval [CI] = 1.31, 1.36), whereas patients aged ≥85 years had 91% higher odds of preventable mortality (aOR = 1.91 and 95% CI = 1.87, 1.94) compared to patients aged 65-74 years. Failure-to-prevent O/E were >1 for all PSIs evaluated with central line-related blood stream infection having a high O/E (747.93). Failure-to-rescue O/E were >1 for 10/11 (91%) PSIs with physiologic and metabolic derangements having the highest O/E (5.98). United States' states with higher quantities of geriatric trauma patients experienced reduced preventable mortality. Odds of preventable mortality increases with age. Perioperative venous thrombotic events, hemorrhage or hematoma, and postoperative physiologic/metabolic derangements produce significant preventable mortalities. United States' states differ in their failure-to-prevent and failure-to-rescue PSIs. Utilization of national guidelines, minimization of central venous catheter use, addressing polypharmacy especially anticoagulation, ensuring operative and procedure-based competencies, and greater incorporation of inpatient geriatricians may serve to reduce preventable mortality in elderly trauma patients.

Timing and burden of persistent critical illnessin UK intensive care units: An observational cohort study.

Persistent critical illness is a recognisable clinical syndrome defined conceptually as when the patient's reason for being in the intensive care unit (ICU) is more related to their ongoing critical illness than their original reason for admission. Our objectives were: (1) to assess the day in ICU on which chronic factors (e.g., age, gender and comorbidities) were more predictive of survival than acute factors (e.g. admission diagnosis, physiological derangements) measured on the day of admission; (2) to assess the consistency of this finding across major patient subgroups and over time and (3) to compare case mix characteristics and outcomes for patients determined to develop persistent critical illness (based on ICU length of stay) with other patients. Observational cohort study using a high-quality clinical database from the national clinical audit of adult critical care. 217 adult ICUs in England, Wales and Northern Ireland. 835,946 adult patients admitted to participating ICUs between 1 April 2009 and 31 March 2016. The main outcome measure was mortality at discharge from acute hospital. We fitted two statistical models ('chronic' and 'acute') and updated these based upon patients with an ICU length of stay of at least 1, 2, etc., up to 28days. The discrimination of the chronic model first exceeded that of the acute model on day 11. Patients with longer stays (>10days) comprised 9% of admissions but used 45% of ICU bed-days. After a mean ICU length of stay of 22days and a subsequent 28days in hospital, 30% died. Persistent critical illness is commonly encountered in clinical practice and is associated with increased healthcare utilisation and adverse outcomes. Improvements in our understanding of the longer term outcomes and in the development of tools to aid prognostication are urgently required - for humane as well as health economic reasons.

Application of beta-blockers in burn management

Severe burn injuries cause chronic inflammation, which produces a subsequent hypermetabolic response that starts immediately and persists for at least 3 years. The hypermetabolic state, which is thought to be due to postburn elevations of endogenous catecholamines and cortisol, is associated with a number of harmful physiologic derangements including immunosuppression, impaired wound healing, muscle catabolism, and hepatic dysfunction. Beta-blockers have become first line agents for reducing these adverse effects of hypermetabolism in severe burns. This review discusses the underlying pharmacological mechanisms demonstrated by clinical studies evaluating the safety and efficacy of beta-blockers in the management of burn injuries. A literature search was performed using the PubMed database to identify articles on beta-blockers and burn management. The review yielded 33 relevant results consisting of randomized controlled trials, original research articles, and meta-analyses in pediatric and adult burn patients. Propranolol administration reduced insulin resistance, lipolysis, proteolysis, cardiac work, and bone loss resulting from burn-associated hypermetabolism. Propranolol also effectively reduced myocardial stress, resting energy expenditure, and central deposition of fat. Recent studies have begun to evaluate incorporation of anabolic agents and rehabilitative exercise therapy. However, at this time propranolol continues to be the most effective therapy for reducing the hypermetabolic response and other morbidities resulting from burn injuries.

358 Induction Agent and Peri-Intubation Hypotension in Patients With Elevated Shock Index: A Retrospective Cohort Analysis Comparing Etomidate and Ketamine

Emergency department (ED) patients undergoing rapid sequence intubation (RSI) often have multiple physiologic derangements and concomitant hemodynamic (HD) instability predisposing them to peri-intubation hypotension (PIH). PIH is thought to be caused in part by effects of the sedative induction agent. Further, PIH is independently associated with increased morbidity and mortality. Thus, it is imperative that the induction agent of choice maintains HD stability. Etomidate and ketamine are the most commonly used agents, however, there is controversy regarding which agent should be used in the setting of HD instability.

Application of bench studies at the bedside to improve outcomes in the management of severe diabetic ketoacidosis in children-a narrative review.

ObjectiveIn this review, we address a few key issues and the challenges faced in the management of severe diabetic ketoacidosis (DKA) in children, highlighting the existing standard of care, supported by evidence and bench studies.BackgroundThe classic triad of DKA namely hyperglycemia, metabolic acidosis and ketonemia warrants immediate attention with fluids and insulin. Correction of dehydration in DKA is of utmost priority and the calculation of fluid volume and choice of fluid have remained a matter of debate. Insulin therapy, to halt the ketone production, in DKA has undergone wide variations in dose and preparation since its discovery. Although the mortality due to severe DKA has remarkably decreased, complications like cerebral edema and acute kidney injury (AKI) continue to haunt the intensivists and endocrinologists on a few occasions.MethodsWe have selected a few important questions in the management of severe DKA in children, addressing the challenges, reviewing the studies, guidelines and bedside practices with evidence in this narrative review.ConclusionsThe focus of management should be to understand and normalise the deranged physiology rather than trying to get normal laboratory reports. This needs careful understanding of the pathogenesis and deriving conclusion from bench studies. With newer studies and evidence, guidelines are revised every few years. There is a trend towards more conservative therapy, with continuous and advanced monitoring. Switching to subcutaneous insulin and oral hydration is done as early as possible with clinical monitoring and resolution of DKA. Management of severe DKA in children can vary from simple fluid titration and insulin infusion in mild cases to a scenario with multiorgan dysfunction requiring intensive monitoring and advanced organ support. Individualisation of therapy to suit the needs with the available evidence and expertise is extremely essential.

MiR-34a/Notch1b mediated autophagy and apoptosis contributes to oxidative stress amelioration by emodin in the intestine of teleost Megalobrama amblycephala

Stress stimulated reactive oxygen species (ROS) excessive accumulation is the principal cause of oxidative damage in aquatic animals. Severe oxidative stress could induce cell fate dysfunction, affect physiologic derangement, growth, and even survival. This study aims to investigate the ameliorative function of emodin in resist to oxidative stress via histomorphology, transcriptome, miRNAs, and mRNA-miRNA integrate analysis in the intestine of Megalobrama amblycephala. Morphologically, emodin alleviated oxidative stress induced autophagy in intestine. Differentially expressed miRNAs induced by oxidative stress and emodin were mainly involved in energy metabolism, oxidative homeostasis, cell apoptosis and cancerization signaling. Specifically, target prediction of miRNAs reveals Notch and apoptosis signaling were dysregulated. mRNA-miRNA integrated analysis reveals miR-34a and Notch1b were actively co-related in the regulatory network, and miR-34a was solidly confirmed as the negative regulator of Notch1b by targeting to the 3’-UTR. Transcriptional expression of key genes reveal emodin alleviates intestinal oxidative stress by activating miR-34a, and subsequently inhibit the expression of Notch receptors (DllA, Jag1b, and Jag2) and down-stream regulators (Hes1, Hey1, and FBW7). Meanwhile, apoptosis-related gene expression (Bax, Casp3, Casp8, Casp9, AIF1, AIF3, CytoC, and CDK4) were activated by oxidative stress, while were alleviated to the control level when treated with emodin. In conclusion, these results suggest that miR-34a/Notch1b is the potential therapeutic target for emodin to ameliorate oxidative stress in M. amblycephala.

Glycaemic Monitoring in Diabetic Kidney Disease – Is HbA1c Reliable?

Diabetic kidney disease (DKD) is a known complication of diabetes mellitus that increases patients’ risks of developing end-stage renal failure requiring dialysis treatment and vulnerability of fatal outcomes resulted from cardiovascular events. Therefore, a good diabetic control among patients with DKD is essential. Nevertheless, monitoring glycaemia in DKD is very challenging. The use of the gold standard glycaemic marker, haemoglobin A1c (HbA1c), is complicated by many hindrances associated with both biochemical and physiological derangements of DKD. Despite the constraints, the Kidney Disease Improving Global Outcome has recommended the use of HbA1c as a reliable glycaemic marker in DKD patients, whose estimated glomerular filtration rate is down to 30 millilitres/minute per 1.73 meter2 . In this article, we discuss the reliability and limitations of HbA1c as an advocated glycaemic marker in DKD. Considering that the reliability of HbA1c is highly dependent on the interpretation of the results, we also highlighted the common potential factors that can affect HbA1c interpretation in patients with DKD. The article also discusses the issues related to the utility of glycated albumin and serum fructosamine as alternative glycaemic biomarkers, and continuous glucose monitoring as a complementary marker to HbA1c in clinical practice. Understanding the HbA1c values and their limitations is important to ensure accurate interpretation of glycaemic status and to achieve optimal diabetic control in patients with DKD.

Meniscus Repair Techniques.

The menisci play a vital role in maintaining knee function and protecting the chondral surfaces. Acute and chronic tears are common injuries among both young athletes and older patients with early degenerative changes. The progression of physiological derangement and chondral injury after meniscus injury and meniscectomy have prompted interest in expanding meniscus repair techniques. Recent literature encourages an attempt at repair in tear patterns previously declared irreparable if the tissue quality allows. The orthopedic surgeon should understand the multitude of techniques available to them and be prepared to combine techniques to optimize the quality of their repair construct. While biological augmentation may show some promising early results, the quality of the current data precludes strong recommendations in their favor.

What's New in Shock, July 2021?

What's New in Shock, July 2021?

DIFFICULT INTUBATION AT BAY! C-MAC FAILS TO PAY!! CRITICAL POSITIONING PAVES THE WAY!!!, DIFFICULT INTUBATION IN A CASE OF OBSTRUCTIVE HYDROCEPHALUS POSTED FOR V.P. SHUNT

Children with gross hydrocephalus present various challenges to the anaesthesiologists. The problems encountered are not only limited to associated congenital abnormalities and physiological derangements due to raised intra cranial tension, even intubation in such cases can pose great difculty owing to the increased head circumference that makes the alignment of oro-pharyngo- [1,3] laryngeal axis under direct laryngoscopy almost impossible . Difcult airway cart, C- MAC, paediatric breoptic bronchioscope and all possible difcult airway armamentarium must be checked to be in place before induction of anaesthesia in such cases to potentially avoid any [2] airway disaster . Here is a case report of a child with gross hydrocephalus posted for emergency VP shunt placement that turned out to be an extremely challenging airway.

Increased time from physiological derangement to critical care admission associates with mortality

BackgroundRapid response systems aim to achieve a timely response to the deteriorating patient; however, the existing literature varies on whether timing of escalation directly affects patient outcomes. Prior studies have been limited to using ‘decision to admit’ to critical care, or arrival in the emergency department as ‘time zero’, rather than the onset of physiological deterioration. The aim of this study is to establish if duration of abnormal physiology prior to critical care admission [‘Score to Door’ (STD) time] impacts on patient outcomes.MethodsA retrospective cross-sectional analysis of data from pooled electronic medical records from a multi-site academic hospital was performed. All unplanned adult admissions to critical care from the ward with persistent physiological derangement [defined as sustained high National Early Warning Score (NEWS) > / = 7 that did not decrease below 5] were eligible for inclusion. The primary outcome was critical care mortality. Secondary outcomes were length of critical care admission and hospital mortality. The impact of STD time was adjusted for patient factors (demographics, sickness severity, frailty, and co-morbidity) and logistic factors (timing of high NEWS, and out of hours status) utilising logistic and linear regression models.ResultsSix hundred and thirty-two patients were included over the 4-year study period, 16.3% died in critical care. STD time demonstrated a small but significant association with critical care mortality [adjusted odds ratio of 1.02 (95% CI 1.0–1.04, p = 0.01)]. It was also associated with hospital mortality (adjusted OR 1.02, 95% CI 1.0–1.04, p = 0.026), and critical care length of stay. Each hour from onset of physiological derangement increased critical care length of stay by 1.2%. STD time was influenced by the initial NEWS, but not by logistic factors such as out-of-hours status, or pre-existing patient factors such as co-morbidity or frailty.ConclusionIn a strictly defined population of high NEWS patients, the time from onset of sustained physiological derangement to critical care admission was associated with increased critical care and hospital mortality. If corroborated in further studies, this cohort definition could be utilised alongside the ‘Score to Door’ concept as a clinical indicator within rapid response systems.

The impact of sarcopenia and acute muscle mass loss on long-term outcomes in critically ill patients with intra-abdominal sepsis.

BackgroundSarcopenia is a known risk factor for poor outcomes across many chronic diseases. The impact on outcomes of both pre‐existing sarcopenia and acute muscle wasting (AMW) in acute critical illness caused by sepsis remain unclear.MethodsWe conducted a prospective longitudinal cohort study of critically ill patients with intra‐abdominal sepsis utilizing abdominal computed tomography at sepsis onset to determine baseline skeletal muscle index (SMI). Biomarkers of inflammation and catabolism were measured through 28 days while hospitalized. We performed follow‐up evaluations of strength and physical function at 3, 6, and 12 months, with interval CT analyses at 3 and 12 months to evaluate changes in muscle mass. Measured clinical outcomes included development of chronic critical illness (≥14 days in intensive care with persistent organ dysfunction), long‐term functional status, and 1 year mortality.ResultsAmong 47 sepsis patients enrolled (mean age 53 ± 14 years), half (n = 23; 49%) were sarcopenic at baseline. Overall, sepsis patients exhibited acute and persistent muscle wasting with an average 8% decrease in SMI from baseline at 3 months (P = 0.0008). Sarcopenic (SAR) and non‐sarcopenic (NSAR) groups were similar in regards to age and comorbidity burden. SAR patients had greater acute physiologic derangement (APACHE II, 18 vs. 12.5), higher incidence of multiple organ failure (57% vs. 17%), longer hospital (21 vs. 12 days) and intensive care unit length of stays (13 vs. 4 days), and higher inpatient mortality (17% vs. 0%; all P < 0.05). Pre‐existing SAR was a strong independent predictor of early death or developing chronic critical illness (odds ratio 11.87, 95% confidence interval CI 1.88–74.9; P = 0.009, area under the curve 0.880) and was associated with significantly higher risk of 1‐year mortality (34.9% vs. 4.2%, p = 0.007). Lower baseline SMI was also predictive of poor functional status at 12 months (OR 0.89, 95% confidence interval 0.80–0.99; p = 0.039, area under the curve 0.867). Additionally, SAR patients had AMW with persistent muscle mass loss at 3 months that was associated with decreased health‐related quality of life and SF‐36 physical function domains (P < 0.05). Persistent AMW at 3 months was not predictive of mortality or poor functional status, with return to near‐baseline muscle mass among sepsis survivors by 6 months.ConclusionsCritically ill patients have an acute and persistent loss of muscle mass after intra‐abdominal sepsis, which is associated with decreased health‐related quality of life and physical function at 3 months. However, pre‐existing sarcopenia, rather than persistent acute muscle mass loss at 3 months after sepsis, is independently associated with poor long‐term functional status and increased 1 year mortality.

Analysis of urgent/emergent conversions from monitored anesthesia care to general anesthesia with airway instrumentation

BackgroundMonitored Anesthesia Care (MAC) is an anesthetic service involving the titration of sedatives/analgesics to achieve varying levels of sedation while avoiding general anesthesia (GA) and airway instrumentation. The goal of our study was to determine the overall incidence of conversion from MAC to general anesthesia with airway instrumentation and elucidate reasons and risk factors for conversion.MethodsIn this retrospective observational study, all non-obstetric adult patients who received MAC from July 2002 to July 2015 at Mount Sinai Hospital were electronically screened for inclusion via a clinical database. Patient, procedure, anesthetic, and practitioner data were all collected and analyzed to generate descriptive analyses. Subsequent univariate and multivariate analyses were used to identify specific risk factors associated with conversion to GA.ResultsOverall, 0.50% (1097/219,061) of MAC cases were converted to GA. Approximately half of conversions were due to the patient’s “intolerance” of MAC (with or without failed regional anesthesia), while the other half were due to physiologic derangements. Body mass index, male sex, American Society of Anesthesiologists Physical Status Classification, anesthesia team composition, and surgical specialty were all associated with risk of conversion to GA.ConclusionsThis is one of the first and largest retrospective studies aimed at identifying reasons and risk factors associated with the conversion of MAC to GA. These findings may be used to help better anticipate or prevent these events.

Not All Piggybacks Are Equal: A Retrospective Cohort Analysis of Variation in Anhepatic Transcaval Pressure Gradient and Acute Kidney Injury During Liver Transplant.

Complete inferior vena cava clamping in cavalreplacement during livertransplantis associated with substantial physiological derangement and postoperative morbidity. Partial clamping in the piggyback technique may be relatively protective, but evidence is lacking. Having observed substantial variation in transhepatic inferior vena cava pressure gradient with piggyback, we hypothesized that the causative mechanism is the extent of caval clamping rather than the surgical approach. We used internal jugular and femoral catheters to estimate suprahepatic and infrahepatic inferior vena cava pressures during clamping. Pressure gradients were calculated, and distributions were compared by surgical technique. We estimated adjusted odds ratios for pressure gradient on acute kidney injury at 72 hours. In 115 case records, we observed substantial variation in maximum pressure gradient; median values were 18.0 mm Hg(interquartile range, 8.0-25.0 mm Hg) with the piggyback technique and 24.0 mm Hg (interquartile range, 19.5-27.0 mm Hg) with caval replacement. Incidence of acute kidney injury was 25% (29 patients). Pressure gradient was linearly associated with probability of acute kidney injury (odds ratio, 1.06; 95% CI, 1.01-1.13). We report 2 novel findings. (1) Anhepatic inferior vena cavapressuregradient variedsubstantially in individuals undergoing piggyback, and (2) gradient was positively associatedwith early acute kidney injury. We hypothesize that this (unmeasured) variation explains the conflictingfindings ofprevious studies that compared surgical techniques. Also, we propose that caval pressure gradient could be routinely assessed to optimize real-time piggyback clamp position during livertransplant surgery.

Impact of postoperative hypothermia on outcomes after off-pump coronary artery bypass grafting.

Even though the physiological derangements caused by hypothermia are well described, there is no consensus about its impact on postoperative outcomes. The aim of this study is to assess the effect of postoperative hypothermia on outcomes after off-pump coronary artery bypass surgery. A total of 1979 patients undergoing isolated off-pump coronary artery bypass surgery in a single center in the period 2007-2018 were classified according to their axillary temperature measurement at intensive care unit admission postoperatively to either hypothermic (<36°C) or normothermic (≥36°C). Between-group differences on baseline characteristics and postoperative outcomes were assessed before and after propensity score matching. Data analysis showed that 582 patients (29.4%) were hypothermic (median temperature 35.5°C) and 1397 patients (70.6%) were normothermic (median temperature 36.4°C). Using propensity score matching, 567 patient pairs were created. Patients with hypothermia exhibited a higher rate of postoperative transfusion of at least three red cell concentrate units (14.3% vs 9%, p = 0.005), a longer intubation duration (median duration, 6 vs 5 h, p < 0.0001), and a longer intensive care unit stay (median stay, 1.6 vs 1.3 days, p = 0.008). There was no difference in reoperation for bleeding, renal replacement therapy, infections, and mortality between the two groups. Even though associated with a higher blood transfusion requirement and a slightly longer intensive care unit stay, mild postoperative hypothermia was not associated with a higher morbidity and mortality.

Clinical impact of accepting or rejecting a recommendation from a clinical decision support system-assisted antibiotic stewardship program.

Outcomes associated with physician responses to recommendations from an antimicrobial stewardship program (ASP) at an individual patient level have not yet been assessed. We aimed to compare clinical characteristics and mortality risk among patients for whom recommendations from an ASP were accepted or refused. A prospective cohort study was performed with hospitalized adults who received intravenous or oral antimicrobials at a 677-bed academic centre in Canada in 2014-2017. We included patients with an alert produced by a clinical decision support system (CDSS) for whom a recommendation was made by the pharmacist to the attending physician. The outcome was 90-day in-hospital all-cause mortality. We identified 3,197 recommendations throughout the study period, of which 2,885 (90.2%) were accepted. The median length of antimicrobial treatment was significantly shorter when a recommendation was accepted (0.26 versus 1.78 d; p < 0.001). Refusal of a recommendation was not associated with mortality (odds ratio 1.32; 95% confidence interval, 0.93 to 1.89; p = 0.12). The independent risk factors associated with in-hospital mortality were age, Charlson Comorbidity Index score, admission to a critical care unit, duration between admission and recommendation, and issuance of a recommendation on a carbapenem. The duration of antimicrobial treatment was significantly shorter when a recommendation originating from a CDSS-assisted ASP program was accepted. Future prospective studies including potential residual confounding variables, such as the source of infection or physiological derangement, might help in understanding whether CDSS-assisted ASP will have a direct impact on patient mortality.

Damage control surgery in lung trauma.

Damage control techniques applied to the management of thoracic injuries have evolved over the last 15 years. Despite the limited number of publications, information is sufficient to scatter some fears and establish management principles. The severity of the anatomical injury justifies the procedure of damage control in only few selected cases. In most cases, the magnitude of the physiological derangement and the presence of other sources of bleeding within the thoracic cavity or in other body compartments constitutes the indication for the abbreviated procedure. The classification of lung injuries as peripheral, transfixing, and central or multiple, provides a guideline for the transient bleeding control and for the definitive management of the injury: pneumorraphy, wedge resection, tractotomy or anatomical resection, respectively. Identification of specific patterns such as the need for resuscitative thoracotomy, or aortic occlusion, the existence of massive hemothorax, a central lung injury, a tracheobronchial injury, a major vascular injury, multiple bleeding sites as well as the recognition of hypothermia, acidosis or coagulopathy, constitute the indication for a damage control thoracotomy. In these cases, the surgeon executes an abbreviated procedure with packing of the bleeding surfaces, primary management with packing of some selected peripheral or transfixing lung injuries, and the postponement of lung resection, clamping of the pulmonary hilum in the most selective way possible. The abbreviation of the thoracotomy closure is achieved by suturing the skin over the wound packed, or by installing a vacuum system. The management of the patient in the intensive care unit will allow identification of those who require urgent reintervention and the correction of the physiological derangement in the remaining patients for their scheduled reintervention and definitive management.

Congenital diaphragmatic hernia: a narrative review of controversies in neonatal management.

The consequences of most hernias can be immediately corrected by surgical repair. However, this isn’t always the case for children born with a congenital diaphragmatic hernia. The derangements in physiology encountered immediately after birth result from pulmonary hypoplasia and hypertension caused by herniation of abdominal contents into the chest early in lung development. This degree of physiologic compromise can vary from mild to severe. Postnatal management of these children remains controversial. Although heavily studied, multi-institutional randomized controlled trials are lacking to help determine what constitutes best practice. Additionally, the results of the many studies currently within the literature that have investigated differing aspect of care (i.e., inhaled nitric oxide, ventilator type, timing of repair, role of extracorporeal membrane oxygenation, etc.) are difficult to interpret due to the small numbers investigated, the varying degree of physiologic compromise, and the contrasting care that exists between institutions. The aim of this paper is to review areas of controversy in the care of these complex kids, mainly: the use of fraction of inspired oxygen, surfactant therapy, gentle ventilation, mode of ventilation, medical management of pulmonary hypertension (inhaled nitric oxide, sildenafil, milrinone, bosentan, prostaglandins), the utilization of extracorporeal membrane oxygenation, and the timing of surgical repair.

Ventilatory parameters measured during a physiological study of simulated powered air-purifying respirator failure in healthy volunteers.

Powered air-purifying respirators (PAPR) are a high level of respiratory personal protective equipment. Like all mechanical devices, they are vulnerable to failure. The precise physiological consequences of failure in live subjects have not previously been reported. We conducted an observational safety study simulating PAPR failure in a group of nine healthy volunteers, wearing loose-fitting hoods, who were observed for a period of ten minutes, or until they requested the experiment be aborted, with continuous monitoring of gas exchange. Relative to baseline, participants demonstrated median reductions in peripheral oxygen saturation of 3.5% (95% confidence interval (CI) -4% to -2%; P = 0.0039) and fraction of inspired oxygen of 0.045 (95% CI -0.05 to -0.04; P = 0.0039), and median increases in inspired partial pressure of carbon dioxide of 27 mmHg (95% CI 23.5-32 mmHg; P = 0.0039), end-tidal partial pressure of carbon dioxide of 11 mmHg (95% CI 7-16 mmHg; P = 0.0039) and minute ventilation of 30 l/min (95% CI 19.4-35.9 l/min; P = 0.0039). Median collateral entrainment of room air into the hood was 17.6 l/min (interquartile range 12.3-27.0 l/min). All subjects reported thermal discomfort, with two (22.2%) requesting early termination of the experiment. Whilst the degree of rebreathing in this experiment was not sufficient to cause dangerous physiological derangement, the degree of reported thermal discomfort combined with the consequences of entrainment of possibly contaminated air into the hood, pose a risk to wearers in the event of failure.

Does Liberal Prehospital and In-Hospital Tranexamic Acid Influence Outcome in Severely Injured Patients? A Prospective Cohort Study

BackgroundEarly hemorrhage control is important in trauma-related death prevention. Tranexamic acid (TXA) has shown to be beneficial in patients in hemorrhagic shock, although widespread adoption might result in incorrect TXA administration leading to increased morbidity and mortality.MethodsA 7-year prospective cohort study with consecutive trauma patients admitted to a Level-1 Trauma Center ICU was performed to investigate administration of both pre- and in-hospital TXA and its relation to morbidity and mortality. Indication for prehospital and in-hospital TXA administration was (suspicion of) hemorrhagic shock, and/or systolic blood pressure (SBP) ≤ 90 mmHg. Demographics, data on physiology, resuscitation and outcomes were prospectively collected.ResultsFour hundred and twenty-two patients (71% males, median ISS 29, 95% blunt injuries) were included. Even though TXA patients were more severely injured with more deranged physiology, no differences in outcome were noted. Overall, thrombo-embolic complication rate was 8%. In half the patients, hemorrhagic shock was the indication for prehospital TXA, whereas 79% of in-hospital TXA was given based on suspicion of hemorrhagic shock. Thirteen percent of patients with SBP ≤ 90 mmHg in ED received no TXA at all. Based on SBP alone, 22% of prehospital TXA and 25% of in-hospital TXA were justified.ConclusionsDespite being more severely injured, TXA patients had similar outcome compared to patients without TXA. Thrombo-embolic complication rate was low despite liberal use of both prehospital and in-hospital TXA. Caution should be exercised in selecting patients for TXA, although this might be challenging based on SBP alone in patients who do not yet show signs of deranged physiology on arrival in ED.