Does vasopressor therapy have an indication in hemorrhagic shock?

Effects of Vasopressin Receptor Agonists during the Resuscitation of Hemorrhagic Shock: A Systematic Review and Meta-Analysis of Experimental and Clinical Studies

BACKGROUND

The clinical impact of vasopressin in hemorrhagic shock remains largely unknown.

OBJECTIVE

This systematic review and meta-analysis was designed to investigate the effects of vasopressin receptor agonists during the resuscitation of hemorrhagic shock.

METHODS

A systematic search of PubMed (MEDLINE), Scopus, and PubMed Central was conducted for relevant articles. Experimental (animal) and clinical studies were included. The primary objective was to investigate the correlation of vasopressin receptor agonist use with mortality and various hemodynamic parameters.

RESULTS

Data extraction was possible in thirteen animal studies and two clinical studies. Differences in risk of mortality between patients who received a vasopressin receptor agonist were not statistically significant when compared to those who were not treated with such agents [RR (95% CI): 1.17 (0.67, 2.08); p = 0.562; I² = 50%]. The available data were insufficient to conduct a meta-analysis assessing the effect of vasopressin receptor agonists on hemodynamics. Drawing safe conclusions from animal studies was challenging, due to significant heterogeneity in terms of species and dosage of vasopressin receptor agonists among studies.

CONCLUSIONS

Differences in risk of mortality between patients who received a vasopressin receptor agonist were not statistically significant when compared to those who were not treated with such agents after hemorrhagic shock. More data are needed to deduce certain conclusions.

Association of Early Norepinephrine Administration With 24-Hour Mortality Among Patients With Blunt Trauma and Hemorrhagic Shock

IMPORTANCE

Hemorrhagic shock is a common cause of preventable death after injury. Vasopressor administration for patients with blunt trauma and hemorrhagic shock is often discouraged.

OBJECTIVE

To evaluate the association of early norepinephrine administration with 24-hour mortality among patients with blunt trauma and hemorrhagic shock.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective, multicenter, observational cohort study used data from 3 registries in the US and France on all consecutive patients with blunt trauma from January 1, 2013, to December 31, 2018. Patients were alive on admission with hemorrhagic shock, defined by prehospital or admission systolic blood pressure less than 100 mm Hg and evidence of hemorrhage (ie, prehospital or resuscitation room transfusion of packed red blood cells, receipt of emergency treatment for hemorrhage control, transfusion of >10 units of packed red blood cells in the first 24 hours, or death from hemorrhage). Blunt trauma was defined as any exposure to nonpenetrating kinetic energy, collision, or deceleration. Statistical analysis was performed from January 15, 2021, to February 22, 2022.

EXPOSURE

Continuous administration of norepinephrine in the prehospital environment or resuscitation room prior to hemorrhage control, according to European guidelines.

MAIN OUTCOMES AND MEASURES

The primary outcome was 24-hour mortality, and the secondary outcome was in-hospital mortality. The average treatment effect (ATE) of early norepinephrine administration on 24-hour mortality was estimated according to the Rubin causal model. Inverse propensity score weighting and the doubly robust approach with 5 distinct analytical strategies were used to determine the ATE.

RESULTS

A total of 52 568 patients were screened for inclusion, and 2164 patients (1508 men [70%]; mean [SD] age, 46 [19] years; median Injury Severity Score, 29 [IQR, 17-36]) presented with acute hemorrhage and were included. A total of 1497 patients (69.1%) required emergency hemorrhage control, 128 (5.9%) received a prehospital transfusion of packed red blood cells, and 543 (25.0%) received a massive transfusion. Norepinephrine was administered to 1498 patients (69.2%). The 24-hour mortality rate was 17.8% (385 of 2164), and the in-hospital mortality rate was 35.6% (770 of 2164). None of the 5 analytical strategies suggested any statistically significant association between norepinephrine administration and 24-hour mortality, with ATEs ranging from -4.6 (95% CI, -11.9 to 2.7) to 2.1 (95% CI, -2.1 to 6.3), or between norepinephrine administration and in-hospital mortality, with ATEs ranging from -1.3 (95% CI, -9.5 to 6.9) to 5.3 (95% CI, -2.1 to 12.8).

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that early norepinephrine infusion was not associated with 24-hour or in-hospital mortality among patients with blunt trauma and hemorrhagic shock. Randomized clinical trials that study the effect of early norepinephrine administration among patients with trauma and hypotension are warranted to further assess whether norepinephrine is safe for patients with hemorrhagic shock.

Preclinical studies of NOS inhibitor T1059 vasopressor activity on the models of acute hemorrhagic shock in rats and dogs

The development of new effective and safe vasopressors is one of the ways to increase the effectiveness of the treatment of hypotensive disorders, the severe forms of which remain a common cause of death in all countries of the world. Previously, we synthesized the original compound T1059, a selective inhibitor of eNOS/iNOS which has a pronounced vasoconstrictive effect. Here we show its vasopressor activity in models of the early stage of acute hemorrhagic shock in rats and dogs, as part of preclinical studies. The results indicate NOS inhibitor T1059 as a potent long-acting vasopressor. Its single parenteral administration in sufficiently safe doses (1/50-1/9 LD10), caused in rats and dogs a rapid increase in vascular tone, accompanied by a prolonged hypertensive effect (within 90-120 min in rats, and within 115 min in dogs). The repeated administration of T1059 at low doses (1/3 of the first dose) made it possible to considerably (by at least 60 min) prolong a significant vasopressor effect. In all schemes, T1059 administration considerably inhibited the development of threatening cardiorespiratory disorders and significantly (p = 0.0026-0.0098) increased the short-term survival of experimental animals, formally extending the duration of the "golden hour" by 2 times. These data indicate that NOS inhibitors and, in particular, compound T1059, are able to create new opportunities in the treatment of hypotensive disorders, including the provision of assistance at the prehospital stage of treatment of such pathologies.

Effect of C-Clamp Application on Hemodynamic Instability in Polytrauma Victims with Pelvic Fracture

Background and Objectives: C-clamp application may reduce mortality in patients with unstable pelvic fractures and hemodynamic instability. Decreasing C-clamp use over the past decades may have resulted from concerns about its effectiveness and safety. The purpose of this study was to document effective hemodynamic stabilization after C-clamp application by means of vital parameters (primary outcome parameter), and the subsequent effect on metabolic indices and volume management (secondary outcome parameters). Materials and Methods: C-clamp application was performed between 2014 and 2021 for n = 13 patients (50 ± 18 years) with unstable pelvic fractures and hemodynamic instability. Vital parameters, metabolic indices, volume management, and the correlation of factors and potential changes were analyzed. Results: After C-clamp application, increases were measured in systolic blood pressure (+15 mmHg; p = 0.0284) and mean arterial pressure (+12 mmHg; p = 0.0157), and a reduction of volume requirements (p = 0.0266) and bolus vasoactive medication needs (p = 0.0081) were observed. The earlier C-clamp application was performed, the greater the effect (p < 0.05; r > 0.6). Heart rate, shock index, and end-tidal CO2 were not significantly altered. The extent of base deficit, hemoglobin, and lactate did not correlate with changes in vital parameters. Conclusions: In the majority of hemodynamically unstable trauma patients not responding to initial fluid resuscitation and severe pelvic fracture, early C-clamp application had an additive effect on hemodynamic stabilization and reduction in volume substitution. Based on these findings, there is still a rationale for considering early C-clamp stabilization in this group of severely injured patients.

Renal Microcirculation and Function in a Pig Model of Hemorrhagic Shock Resuscitation with Norepinephrine

RATIONALE

Norepinephrine (NE) is commonly used in combination with fluid during resuscitation of hemorrhagic shock, however its impact on kidney microcirculation, oxygenation and function is still unknown in this setting.

OBJECTIVES

During hemorrhagic shock resuscitation, does a combination of fluid and norepinephrine affect kidney oxygenation tension, kidney microcirculatory perfusion and 48-hour kidney function, as compared to fluid alone?

METHODS

Hemorrhagic shock was induced in 24 pigs and 8 pigs were included as sham. Resuscitation of hemorrhagic shock was performed, using a closed-loop device, either by fluid alone (0.9% NaCl, Fluid group) or associated with the administration of NE at two doses (moderate dose: mean rate of 0.64 µg.kg-1.min-1 and high dose: mean rate of 1.57 µg.kg-1.min-1) in order to obtain SAP (systolic arterial pressure) target of 80-90 mmHg. Resuscitation was followed by transfusion of the withdrawn blood.

MEASUREMENTS AND MAIN RESULTS

The amount of fluid required to reach SAP target was lower in NE groups than in Fluid group with subsequent less hemodilution. Norepinephrine restored kidney microcirculation, oxygenation, and function in a manner comparable to that achieved with fluid resuscitation alone. There were no histological differences among animals resuscitated with Fluid or with NE.

CONCLUSION

In pigs with hemorrhagic shock, resuscitation with a combination of NE and fluid restored kidney microcirculation and oxygenation, as well as renal function, in a manner comparable to fluid resuscitation alone and without differences between the two NE doses. NE administration led to a fluid volume sparing effect with subsequently less hemodilution.

Comparison of the Previous and Current Trauma-Related Shock Classifications: A Retrospective Cohort Study from a Level I Trauma Center

PURPOSE

The aim was to examine the predictive value of the hypovolemic shock classification currently accepted by the Advanced Trauma Life Support (ATLS) program over the previous one, which used only vital signs (VS) for patient allocation. The primary outcome was 30-day mortality; as secondary outcome, heart rate (HR), systolic blood pressure (SBP), Glasgow Coma Scale (GCS) and base deficit (BD) data were compared and investigated in terms of mortality prediction.

METHODS

Retrospective analysis at a level I trauma center between 2014 and 2019. Adult patients treated by trauma teams were allocated into severity classes (I-IV) based on the criteria of the current and previous ATLS classifications, respectively. The prognostic values for the classifications were determined with Fisher's exact test and χ2 test for independence, and compared with the 2-proportion Z test. The individual variables were analyzed with receiver-operating characteristic (ROC) analyses.

RESULTS

A total of 156 patients met the inclusion criteria. Mortality was effectively predicted by both classifications, and there was no statistically significant difference between the predictive performances. According to ROC analyses, GCS, BD and SBP had significant prognostic values while HR change was ineffective in this regard.

CONCLUSIONS

The currently used ATLS shock classification does not appear to be superior to the VS-based previous classification. GCS, BD and SBP are useful parameters to predict the prognosis. Changes in HR do not reflect the clinical course accurately; thus, further studies will be needed to determine the value of this parameter in trauma-associated hypovolemic-hemorrhagic shock conditions.

Biological Connection of Psychological Stress and Polytrauma under Intensive Care: The Role of Oxytocin and Hydrogen Sulfide

This paper explored the potential mediating role of hydrogen sulfide (H2S) and the oxytocin (OT) systems in hemorrhagic shock (HS) and/or traumatic brain injury (TBI). Morbidity and mortality after trauma mainly depend on the presence of HS and/or TBI. Rapid "repayment of the O2 debt" and prevention of brain tissue hypoxia are cornerstones of the management of both HS and TBI. Restoring tissue perfusion, however, generates an ischemia/reperfusion (I/R) injury due to the formation of reactive oxygen (ROS) and nitrogen (RNS) species. Moreover, pre-existing-medical-conditions (PEMC's) can aggravate the occurrence and severity of complications after trauma. In addition to the "classic" chronic diseases (of cardiovascular or metabolic origin), there is growing awareness of psychological PEMC's, e.g., early life stress (ELS) increases the predisposition to develop post-traumatic-stress-disorder (PTSD) and trauma patients with TBI show a significantly higher incidence of PTSD than patients without TBI. In fact, ELS is known to contribute to the developmental origins of cardiovascular disease. The neurotransmitter H2S is not only essential for the neuroendocrine stress response, but is also a promising therapeutic target in the prevention of chronic diseases induced by ELS. The neuroendocrine hormone OT has fundamental importance for brain development and social behavior, and, thus, is implicated in resilience or vulnerability to traumatic events. OT and H2S have been shown to interact in physical and psychological trauma and could, thus, be therapeutic targets to mitigate the acute post-traumatic effects of chronic PEMC's. OT and H2S both share anti-inflammatory, anti-oxidant, and vasoactive properties; through the reperfusion injury salvage kinase (RISK) pathway, where their signaling mechanisms converge, they act via the regulation of nitric oxide (NO).

Vasopressors in Trauma: A Never Event?

Vasopressor use in severely injured trauma patients is discouraged due to concerns that vasoconstriction will worsen organ perfusion and result in increased mortality and organ failure in hypotensive trauma patients. Hypotensive resuscitation is advocated based on limited data that lower systolic blood pressure and mean arterial pressure will result in improved mortality. It is classically taught that hypotension and hypovolemia in trauma are associated with peripheral vasoconstriction. However, the pathophysiology of traumatic shock is complex and involves multiple neurohormonal interactions that are ultimately manifested by an initial sympathoexcitatory phase that attempts to compensate for acute blood loss and is characterized by vasoconstriction, tachycardia, and preserved mean arterial blood pressure. The subsequent hypotension observed in hemorrhagic shock reflects a sympathoinhibitory vasodilation phase. The objectives of hemodynamic resuscitation in hypotensive trauma patients are restoring adequate intravascular volume with a balanced ratio of blood products, correcting pathologic coagulopathy, and maintaining organ perfusion. Persistent hypotension and hypoperfusion are associated with worse coagulopathy and organ function. The practice of hypotensive resuscitation would appear counterintuitive to the goals of traumatic shock resuscitation and is not supported by consistent clinical data. In addition, excessive volume resuscitation is associated with adverse clinical outcomes. Therefore, in the resuscitation of traumatic shock, it is necessary to target an appropriate balance with intravascular volume and vascular tone. It would appear logical that vasopressors may be useful in traumatic shock resuscitation to counteract vasodilation in hemorrhage as well as other clinical conditions such as traumatic brain injury, spinal cord injury, multiple organ dysfunction syndrome, and vasodilation of general anesthetics. The purpose of this article is to discuss the controversy of vasopressors in hypotensive trauma patients and advocate for a nuanced approach to vasopressor administration in the resuscitation of traumatic shock.

Retrospective study on rib fractures: smoking and alcohol matter for mortality and complications

Background

Rib fractures and substance use are both common in trauma patients, but there is little data on how smoking and alcohol use may be associated with outcomes in these patients. We assessed the association between smoking or alcohol use disorder (AUD) and outcomes in patients with rib fractures.

Methods

We used institutional databases to conduct a retrospective review of patients with rib fractures at the only American College of Surgeons-verified adult level 1 trauma center in a rural state between 2015 and 2019. The key exposure variables were smoking and AUD. The key outcome variables were mortality and pulmonary complications (pneumonia, adult respiratory distress syndrome, and pneumothorax). We used multivariable regression for analysis and directed acyclic graphs to identify variables for adjustment.

Results

We identified 1880 eligible patients with rib fractures, including 693 (37%) who were smokers and 204 (11%) who had AUD. Compared with non-smokers, smokers were younger, more often male, and had lower mortality rates. Regression showed that smokers had a lower likelihood of mortality (OR 0.48; 95% CI 0.27 to 0.87; p=014). Likelihood of pneumonia, ARDS, and pneumothorax was not different between smokers and non-smokers. Compared with patients without AUD, patients with AUD were older, more often male, and had higher likelihood of pneumonia and lower likelihood of pneumothorax. Regression showed that patients with AUD had higher likelihood of pneumonia (OR 1.82; 95% CI 1.24 to 2.68; p=0.002) and lower likelihood of pneumothorax (OR 0.51; 95% CI 0.33 to 0.75; p=0.002).

Discussion

In trauma patients with rib fractures treated at a level 1 trauma center over 5 years, smoking was associated with decreased risk of mortality. These findings have implications for risk stratification and clinical decision-making for patients with rib fractures.

Level of evidence

III

Early vasopressor administration in pediatric blunt liver and spleen injury: An ATOMAC+ study

BACKGROUND

No prior studies have examined the outcomes of early vasopressor use in children sustaining blunt liver or spleen injury (BLSI).

METHODS

A planned secondary analysis of vasopressor use from a 10-center, prospective study of 1004 children with BLSI. Inverse probability of treatment weighting (IPTW) was used to compare patients given vasopressors <48 h after injury to controls based on pretreatment factors. A logistic regression was utilized to assess survival associated with vasopressor initiation factors on mortality and nonoperative management (NOM) failure.

RESULTS

Of 1004 patients with BLSI, 128 patients were hypotensive in the Pediatric Trauma Center Emergency Department (ED); 65 total patients received vasopressors. Hypotension treated with vasopressors was associated with a sevenfold increase in mortality (AOR = 7.6 [p < 0.01]). When excluding patients first given vasopressors for cardiac arrest, the risk of mortality increased to 11-fold (AOR = 11.4 [p = 0.01]). All deaths in patients receiving vasopressors occurred when started within the first 12 h after injury. Vasopressor administration at any time was not associated with NOM failure.

CONCLUSION

After propensity matching, early vasopressor use for hypotension in the ED was associated with an increased risk of death, but did not increase the risk of failure of NOM.

LEVEL OF EVIDENCE

Level III prognostic and epidemiological, prospective.

Cerebral effects of resuscitation with either epinephrine or vasopressin in an animal model of hemorrhagic shock

PURPOSE

The use of epinephrine (EN) or vasopressin (VP) in hemorrhagic shock is well established. Due to its specific neurovascular effects, VP might be superior in concern to brain tissue integrity. The aim of this study was to evaluate cerebral effects of either EN or VP resuscitation after hemorrhagic shock.

METHODS

After shock induction fourteen pigs were randomly assigned to two treatment groups. After 60 min of shock, resuscitation with either EN or VP was performed. Hemodynamics, arterial blood gases as well as cerebral perfusion pressure (CPP) and brain tissue oxygenation (PtiO2) were recorded. Interstitial lactate, pyruvate, glycerol and glutamate were assessed by cerebral and subcutaneous microdialysis. Treatment-related effects were compared using one-way ANOVA with post hoc Bonferroni adjustment (p < 0.05) for repeated measures.

RESULTS

Induction of hemorrhagic shock led to a significant (p < 0.05) decrease of mean arterial pressure (MAP), cardiac output (CO) and CPP. Administration of both VP and EN sufficiently restored MAP and CPP and maintained physiological PtiO2 levels. Brain tissue metabolism was not altered significantly during shock and subsequent treatment with VP or EN. Concerning the excess of glycerol and glutamate, we found a significant EN-related release in the subcutaneous tissue, while brain tissue values remained stable during EN treatment. VP treatment resulted in a non-significant increase of cerebral glycerol and glutamate.

CONCLUSIONS

Both vasopressors were effective in restoring hemodynamics and CPP and in maintaining brain oxygenation. With regards to the cerebral metabolism, we cannot support beneficial effects of VP in this model of hemorrhagic shock.

Addition of terlipressin to initial volume resuscitation in a pediatric model of hemorrhagic shock improves hemodynamics and cerebral perfusion

Hemorrhagic shock is one of the leading causes of mortality and morbidity in pediatric trauma. Current treatment based on volume resuscitation is associated to adverse effects, and it has been proposed that vasopressors may be used in the pharmacological management of trauma. Terlipressin has demonstrated its usefulness in other pediatric critical care scenarios and its long half-life allows its use as a bolus in an outpatient critical settings. The aim of this study was to analyze whether the addition of a dose of terlipressin to the initial volume expansion produces an improvement in hemodynamic and cerebral perfusion at early stages of hemorrhagic shock in an infant animal model. We conducted an experimental randomized animal study with 1-month old pigs. After 30 minutes of hypotension (mean arterial blood pressure [MAP]<45 mmHg) induced by the withdrawal of blood over 30 min, animals were randomized to receive either normal saline (NS) 30 mL/kg (n = 8) or a bolus of 20 mcg/kg of terlipressin plus 30 mL/kg of normal saline (TP) (n = 8). Global hemodynamic and cerebral monitoring parameters, brain damage markers and histology samples were compared. After controlled bleeding, significant decreases were observed in MAP, cardiac index (CI), central venous pressure, global end-diastolic volume index (GEDI), left cardiac output index, SvO₂, intracranial pressure, carotid blood flow, bispectral index (BIS), cerebral perfusion pressure (CPP) and increases in systemic vascular resistance index, heart rate and lactate. After treatment, MAP, GEDI, CI, CPP and BIS remained significantly higher in the TP group. The addition of a dose of terlipressin to initial fluid resuscitation was associated with hemodynamic improvement, intracranial pressure maintenance and better cerebral perfusion, which would mean protection from ischemic injury. Brain monitoring through BIS was able to detect changes caused by hemorrhagic shock and treatment.

Impact of high-dose norepinephrine during intra-hospital damage control resuscitation of traumatic haemorrhagic shock: A propensity-score analysis

INTRODUCTION

The use of norepinephrine (NE) during uncontrolled haemorrhagic shock (HS) has mostly been investigated in experimental studies. Clinical data including norepinephrine dose and its impact on fluid resuscitation and organ function are scarce. We hypothesized that there is great variability in NE use and that high doses of NE could lead to increased organ dysfunction as measured by the sequential organ failure assessment (SOFA).

METHOD

We included patients with HS (systolic blood pressure < 90 mmHg in severely injured patients) who required haemostasis surgery and a transfusion of more than 4 packed red blood cells (PRBC) in the first 6 h of admission and the used of norepinephrine infusion to maintain the blood pressure goal, between admission and the end of haemostasis surgery in a prospective trauma database. A ROC curve determined that, using Youden's criterion, a dose of NE ≥ 0.6 µg/kg/min was the optimal threshold associated with intrahospital mortality. Patients were compared according to this threshold in a propensity score (PS) model. In a generalized linear mixed model, we searched for independent factors associated with a SOFA ≥ 9 at 24 h RESULTS: A total of 89 patients were analysed. Fluid infusion rate ranged from 1.43 to 57.9 mL/kg/h and norepinephrine infusion rate from 0.1 to 2.8 µg/kg/min. The HDNE group received significantly less fluid than the LDNE group. This dose is associated with a higher SOFA score at 24h: 9 (7-10) vs. 7 (6-9) (p = 0.003). Factors independently associated with a SOFA score ≥ 9 at 24 h were maximal norepinephrine rate ≥ 0.6 µg/kg/min (OR 6.69, 95% CI 1.82 - 25.54; p = 0.004), non-blood resuscitation volume < 9 mL/kg/h (OR 3.98, 95% CI 1.14 - 13.95; p = 0.031) and lactate at admission ≥ 5 mmol/L (OR 5.27, 95% CI 1.48 - 18.77; p = 0.010) CONCLUSION: High dose of norepinephrine infusion is associated with deleterious effects as attested by a higher SOFA score at 24 h and likely hypovolemia as measured by reduced non-blood resuscitation volume. We did not find any significant difference in mortality over the long term.

The impact of early administration of vasopressor agents for the resuscitation of severe hemorrhagic shock following blunt trauma

Background

When resuscitating patients with hemorrhagic shock following trauma, fluid volume restriction and permissive hypotension prior to bleeding control are emphasized along with the good outcome especially for penetrating trauma patients. However, evidence that these concepts apply well to the management of blunt trauma is lacking, and their use in blunt trauma remains controversial. This study aimed to assess the impact of vasopressor use in patients with blunt trauma in severe hemorrhagic shock.

Methods

In this single-center retrospective study, we reviewed records of blunt trauma patients with hemorrhagic shock and included patients with a probability of survival < 0.6. Vital signs on arrival, characteristics, examinations, concomitant injuries and severity, vasopressor use and dose, and volumes of crystalloids and blood infused were compared between survivors and non-survivors. Data are described as median (25–75% interquartile range) or number.

Results

Forty patients admitted from April 2014 to September 2019 were included. Median Injury Severity Score in survivors vs non-survivors was 41 (36–48) vs 45 (34–51) (p = 0.48), with no significant difference in probability of survival between the two groups (0.22 [0.12–0.48] vs 0.21 [0.08–0.46]; p = 0.93). Despite no significant difference in patient characteristics and injury severity, non-survivors were administered vasopressors significantly earlier after admission and at significantly higher doses. Total blood transfusion amount administered within 24 h after admission was significantly higher in survivors (8430 [5680–9320] vs 6540 [4550–7880] mL; p = 0.03). Max catecholamine index was significantly higher in non-survivors (2 [0–4] vs 14 [10–18]; p = 0.008), and administered vasopressors were terminated significantly earlier (12 [4–26] vs 34 [10–74] hours; p = 0.026) in survivors.

Although the variables of severity of the patients had no significant differences, vasopressor use (Odds ratio [OR] = 21.32, 95% confident interval [CI]: 3.71–121.6; p = 0.0001) and its early administration (OR = 10.56, 95%CI: 1.90–58.5; p = 0.005) indicated significant higher risk of death in this study.

Conclusion

Vasopressor administration and high-dose use for resuscitation of hemorrhagic shock following severe blunt trauma are potentially associated with increased mortality. Although the transfused volume of blood products tends to be increased when resuscitating these patients, early termination of vasopressor had better to be considered.

Recognition, Treatment, and Monitoring of Canine Hypovolemic Shock in First Opinion Practice in the United Kingdom

The aim of this study was to gain a greater understanding of the detection, treatment, and monitoring of hypovolemic shock (HVS) in dogs by general practitioners in the United Kingdom (UK). An online survey was devised and distributed by email to first opinion practices in the UK. All veterinarians working in first opinion practice treating small animals were eligible to complete the survey. Most respondents (n = 164, 93%) were confident with HVS diagnosis. Isotonic crystalloid fluids were the most common fluid type for first-line treatment and administered as a 10-30 mL/kg bolus over 10-30 minutes by 57% respondents. Initial intravenous isotonic crystalloid fluid rates for HVS management ranged from maintenance fluid requirements to 90 mL/kg/hr for an undefined time period. A synthetic colloid was the most popular second-line fluid choice, typically considered after a total administered volume of 60-90 mL/kg of isotonic crystalloid fluids. Only 72 respondents (40.7%) were able to measure blood lactate in-house, which was used routinely by 36 respondents (20.3%) for initial treatment decision making. Respondents treating HVS most frequently were more likely to use lactate for initial decision making (P = .008). This study highlighted variabilities in the initial approach, fluid management strategies and monitoring instituted by UK general practitioners when faced with canine patients in HVS. This suggests that there is a discrepancy in what is determined to be the most optimal diagnostic and treatment plan for canine HVS patients.

Femoral arterial and central venous catheters in the trauma resuscitation room

BACKGROUND

Arterial and central venous femoral catheters (fAC-CVC) use during the initial management of severe trauma patients is not a standard technique in most trauma centers. Arguments in favor of their use are: continuous monitoring of blood pressure, safe drug administration, easy blood sampling and potentially large bore venous access. The lack of evidence makes the practice heterogeneous. The aim of the present study was to describe the use and complications of fAC-CVC in the trauma bay in two centers where they are routinely used.

METHODS

This was a retrospective analysis of routine fAC-CVC use from two French trauma centers. All patients admitted directly to the trauma resuscitation room were included. Demographic, clinical and biological data were collected from the scene to discharge to describe the use of catheters during initial trauma management including infectious, mechanical and thrombotic complications.

RESULTS

243 pairs of femoral catheters were inserted among 692 patients admitted in both trauma centers. Femoral AC-CVC use was more frequent in critically ill patients with higher ISS 26 [17; 41] vs 13 [8; 24], p < 0.001(median [quartile 1-3]), severe traumatic brain injury (AIS head 1[0-4] vs 0[0-3], p < 0.001), lower systolic blood pressure, 92 (37) vs 113 (28) mmHg, p < 0.001 mean (standard deviation), lower haemoglobin on arrival, 10.9 (3) vs 13.3 (2.1) g/dL (p < 0.001), and higher blood lactate concentration, 4.0 (3.9) vs 2.1 (1.8) mmol/L (p < 0.001). In patients with fAC-CVC use time in the trauma room was longer, 46 [40;60] vs 30 [20;40] minutes (p < 0.05). In total 52 colonizations and 3 bloodstream infections were noted in 1000 catheter days. An incidence of 12% of mechanical complications and of 42% deep venous thromboses were observed. Of the latter none was associated with confirmed pulmonary embolism.

CONCLUSION

Femoral AC-CVC appeared to be deployed more often in critically ill patients, presenting with shock and/or traumatic brain injury in particular. The observed rate of complications in this sample seems to be low compared to reported rates.

Evaluation of capillary leakage after vasopressin resuscitation in a hemorrhagic shock model

Background

Hemorrhagic shock (HS) is a major threat to patients with trauma and spontaneous bleeding. The aim of the study was to investigate early effects of vasopressin on metabolic and hemodynamic parameters and endothelium permeability by measuring capillary leakage compared to those of other resuscitation strategies in a HS model.

Methods

Forty-five Sprague-Dawley rats were randomized into five groups: S group (n = 5), sham-operated rats without shock or resuscitation; HS group (n = 10), HS and no resuscitation; RL group (n = 10), HS and resuscitation with Ringer’s lactate (RL); RLB group (n = 10), HS and resuscitation with two-third shed blood plus RL; and vasopressin group (n = 10), HS and resuscitation with RL, followed by continuous infusion of 0.04 U/kg/min vasopressin. The effects of resuscitation on hemodynamic parameters [mean arterial pressure (MAP), superior mesenteric artery blood flow (MBF), and mesenteric vascular resistances (MVR)], arterial blood gases, bicarbonate, base deficit, and lactate levels as well as on capillary leakage in the lung, ileum, and kidney were investigated. Capillary leakage was evaluated with Evans blue dye extravasation.

Results

In the vasopressin group, the MAP was higher than in the RL and RLB groups (p < 0.001), while MBF was decreased (p < 0.001). MVR were increased only in the vasopressin group (p < 0.001). Capillary leakage was increased in the lungs of the animals in the vasopressin group compared to that in the lungs of animals in the RLB group (p < 0.05); this increase was associated with the lowest partial pressure of oxygen (p < 0.05). Conversely, decreased capillary leakage was observed with vasopressin in the ileum (p < 0.05). Increased capillary leakage was observed in the kidney in the RLB and vasopressin groups (p < 0.05). Lastly, vasopressin use was associated with higher base deficit and lactate levels when compared to the RL and RLB groups (p < 0.001).

Conclusion

Although vasopressin was proposed as a vasoactive drug for provisional hemodynamic optimization in the early phase of HS resuscitation, the overall findings of this experimental study focus on the possible critical side effects of vasopressin on metabolic parameters and endothelium permeability.

The coherence of macrocirculation, microcirculation, and tissue metabolic response during nontraumatic hemorrhagic shock in swine

Hemorrhagic shock is clinically observed as changes in macrocirculatory indices, while its main pathological constituent is cellular asphyxia due to microcirculatory alterations. The coherence between macro‐ and microcirculatory changes in different shock states has been questioned. This also applies to the hemorrhagic shock. Most studies, as well as clinical situations, of hemorrhagic shock include a “second hit” by tissue trauma. It is therefore unclear to what extent the hemorrhage itself contributes to this lack of circulatory coherence. Nine pigs in general anesthesia were exposed to a controlled withdrawal of 50% of their blood volume over 30 min, and then retransfusion over 20 min after 70 min of hypovolemia. We collected macrocirculatory variables, microcirculatory blood flow measurement by the fluorescent microspheres technique, as well as global microcirculatory patency by calculation of Pv‐aCO₂, and tissue metabolism measurement by the use of microdialysis. The hemorrhage led to anticipated changes in macrocirculatory variables with a coherent change in microcirculatory and metabolic variables. In the late hemorrhagic phase, the animals' variables generally improved, probably through recruitment of venous blood reservoirs. After retransfusion, all variables were normalized and remained same throughout the study period. We find in our nontraumatic model consistent coherence between changes in macrocirculatory indices, microcirculatory blood flow, and tissue metabolic response during hemorrhagic shock and retransfusion. This indicates that severe, but brief, hemorrhage with minimal tissue injury is in itself not sufficient to cause lack of coherence between macro‐ and microcirculation.

Early vasopressor use following traumatic injury: a systematic review

OBJECTIVES

Current guidelines suggest limiting the use of vasopressors following traumatic injury; however, wide variations in practice exist. Although excessive vasoconstriction may be harmful, these agents may help reduce administration of potentially harmful resuscitation fluids. This systematic review aims to compare early vasopressor use to standard resuscitation in adults with trauma-induced shock.

DESIGN

Systematic review.

DATA SOURCES

We searched MEDLINE, EMBASE, ClinicalTrials.gov and the Central Register of Controlled Trials from inception until October 2016, as well as the proceedings of 10 relevant international conferences from 2005 to 2016.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials and controlled observational studies that compared the early vasopressor use with standard resuscitation in adults with acute traumatic injury.

RESULTS

Of 8001 citations, we retrieved 18 full-text articles and included 6 studies (1 randomised controlled trial and 5 observational studies), including 2 published exclusively in abstract form. Across observational studies, vasopressor use was associated with increased short-term mortality, with unadjusted risk ratios ranging from 2.31 to 7.39. However, the risk of bias was considered high in these observational studies because patients who received vasopressors were systematically sicker than patients treated without vasopressors. One clinical trial (n=78) was too imprecise to yield meaningful results. Two clinical trials are currently ongoing. No study measured long-term quality of life or cognitive function.

CONCLUSIONS

Existing data on the effects of vasopressors following traumatic injury are of very low quality according to the Grading of Recommendations, Assessment, Development and Evaluation methodology. With emerging evidence of harm associated with aggressive fluid resuscitation and, in selected subgroups of patients, with permissive hypotension, the alternatives to vasopressor therapy are limited. Observational data showing that vasopressors are part of usual care would provide a strong justification for high-quality clinical trials of early vasopressor use during trauma resuscitation.

TRIAL REGISTRATION NUMBER

CRD42016033437.

Vasopressor use following traumatic injury - A single center retrospective study

Objectives

Vasopressors are not recommended by current trauma guidelines, but recent reports indicate that they are commonly used. We aimed to describe the early hemodynamic management of trauma patients outside densely populated urban centers.

Methods

We conducted a single-center retrospective cohort study in a Canadian regional trauma center. All adult patients treated for traumatic injury in 2013 who died within 24 hours of admission or were transferred to the intensive care unit were included. A systolic blood pressure <90 mmHg, a mean arterial pressure <60 mmHg, the use of vasopressors or ≥2 L of intravenous fluids defined hemodynamic instability. Main outcome measures were use of intravenous fluids and vasopressors prior to surgical or endovascular management.

Results

Of 111 eligible patients, 63 met our criteria for hemodynamic instability. Of these, 60 (95%) had sustained blunt injury and 22 (35%) had concomitant severe traumatic brain injury. The subgroup of patients referred from a primary or secondary hospital (20 of 63, 32%) had significantly longer transport times (243 vs. 61 min, p<0.01). Vasopressors, used in 26 patients (41%), were independently associated with severe traumatic brain injury (odds ratio 10.2, 95% CI 2.7–38.5).

Conclusions

In this cohort, most trauma patients had suffered multiple blunt injuries. Patients were likely to receive vasopressors during the early phase of trauma care, particularly if they exhibited signs of neurologic injury. While these results may be context-specific, determining the risk-benefit trade-offs of fluid resuscitation, vasopressors and permissive hypotension in specific patients subgroups constitutes a priority for trauma research going forwards.

Vasopressor use following traumatic injury: protocol for a systematic review

INTRODUCTION

Worldwide, traumatic casualties are projected to exceed 8 million by year 2020. Haemorrhagic shock and brain injury are the leading causes of death following trauma. While intravenous fluids have traditionally been used to support organ perfusion in the setting of haemorrhage, recent investigations have suggested that restricting fluid therapy by tolerating more severe hypotension may improve survival. However, the safety of permissive hypotension remains uncertain, particularly among patients who have suffered a traumatic brain injury. Vasopressors preferentially vasoconstrict blood vessels that supply non-vital organs and capacitance vessels, thereby mobilising the unstressed blood volume. Used as fluid-sparing adjuncts, these drugs can complement resuscitative measures by correcting hypotension without diluting clotting factors or increasing the risk for tissue oedema.

METHODS AND ANALYSIS

We will identify randomised control trials comparing early resuscitation with vasopressors versus placebo or standard care in adults following traumatic injury. Data sources will include MEDLINE, EMBASE, CENTRAL, clinical trial registries and conference proceedings. Two reviewers will independently determine trial eligibility. For each included trial, we will conduct duplicate independent data extraction and risk of bias assessment. We will assess the overall quality of the data for each individual outcome using the GRADE approach.

ETHICS AND DISSEMINATION

We will report this review in accordance with the PRISMA statement. We will disseminate our findings at critical care and trauma conferences and through a publication in a peer-reviewed journal. We will also use this systematic review to create clinical guidelines (http://www.magicapp.org), which will be disseminated in a standalone publication.

TRIAL REGISTRATION NUMBER

CRD42016033437.

Infrarenal aortic clamp reviving a patient from acute surgical haemorrhagic shock: a novel management technique

Surgical management of renal cell carcinoma extending into the inferior vena cava (IVC) is almost always accompanied by massive intraoperative blood loss and associated complications. It is a widely recognised problem, and its active management is essential in improving the perioperative morbidity and mortality. We share our experience with a similar case of open radical nephrectomy with massive blood loss of twice the circulating volume in a duration of <8 surgical hours. Although we emphasise the goals of securing haemostasis, restoration of circulating volume, and efficient management by replacing blood components, in the present case, despite the above-mentioned goals being fulfilled, we were unable to extricate the patient from haemorrhagic shock by conventional means and therefore resorted to desperate measures, namely the novel approach of infrarenal aortic clamping along with higher than recommended vasopressor support. We resorted to this in order to maintain the haemodynamic parameters and to prevent avoidable morbidity and mortality related to persistent intraoperative hypotension. With such an approach, we successfully managed the patient perioperatively, ultimately resulting in the patient being discharged after a week of intensive care unit stay without major complications.

Pharmacologic agents for acute hemodynamic instability: recent advances in the management of perioperative shock- a systematic review

Despite the growing body of evidence evaluating the efficacy of vasoactive agents in the management of hemodynamic instability and circulatory shock, it appears no agent is superior. This is becoming increasingly accepted as current guidelines are moving away from detailed algorithms for the management of shock, and instead succinctly state that vasoactive agents should be individualized and guided by invasive hemodynamic monitoring. This extends to the perioperative period, where vasoactive agent selection and use may still be left to the discretion of the treating physician with a goal-directed approach, consisting of close hemodynamic monitoring and administration of the lowest effective dose to achieve the hemodynamic goals. Successful therapy depends on the ability to rapidly diagnose the etiology of circulatory shock and thoroughly understand its pathophysiology as well as the pharmacology of vasoactive agents. This review focuses on the physiology and resuscitation goals in perioperative shock, as well as the pharmacology and recent advances in vasoactive agent use in its management.

Prehospital volume resuscitation--Did evidence defeat the crystalloid dogma? An analysis of the TraumaRegister DGU® 2002-2012

Background

Various studies have shown the deleterious effect of high volume resuscitation following severe trauma promoting coagulopathy by haemodilution, acidosis and hypothermia. As the optimal resuscitation strategy during prehospital trauma care is still discussed, we raised the question if the amount and kind of fluids administered changed over the recent years. Further, if less volume was administered, fewer patients should have arrived in coagulopathic depletion in the Emergency Department resulting in less blood product transfusions.

Methods

A data analysis of the 100 489 patients entered into the TraumaRegister DGU® (TR-DGU) between 2002 and 2012 was performed of which a total of 23512 patients (23.3 %) matched the inclusion criteria. Volume and type of fluids administered as well as outcome parameter were analysed.

Results

Between 2002 and 2012, the amount of volume administered during prehospital trauma care decreased from 1790 ml in 2002 to 1039 ml in 2012. At the same time higher haemoglobin mean values, higher Quick’s mean values and reduced mean aPTT can be observed. Simultaneously, more patients received catecholamines (2002: 9.2 to 2012: 13.0 %). Interestingly, the amount of volume administered decreased steadily regardless of the presence of shock. Fewer patients were in the need of blood products and the number of massive transfusions (≥10 pRBC) more than halved.

Discussion

The changes in volume therapy might have reduced haemodilution potentially resulting in an increase of the Hb value. During the period observed transfusion strategies have become more restrictiveand ratio based; the percentage of patients receiving MT halved as blood products may imply negative secondary effects. Furthermore, preventing administration of high blood product ratios result in less impairment of coagulation factors and inhibitors and an therfore improved coagulation.

Conclusion

The volume administered in severely injured patients decreased considerably during the last decade possibly supporting beneficial effects such as minimizing the risk of coagulopathy and avoiding potential harmful effects caused by blood product transfusions. Despite outstanding questions in trauma resuscitation, principle evidence merges quickly into clinical practice and algorithms.

Ilio-psoas hematoma in the intensive care unit: a multicentric study

Background

Clinical features and outcomes of patients with spontaneous ilio-psoas hematoma (IPH) in intensive care units (ICUs) are poorly documented. The objectives of this study were to determine epidemiological, clinical, biological and management characteristics of ICU patients with IPH.

Methods

We conducted a retrospective multicentric study in three French ICUs from January 2006 to December 2014. We included IPH diagnosed both at admission and during ICU stay. Surgery and embolization were available 24 h a day for each center, and therapeutic decisions were undertaken after pluridisciplinary discussion. All IPHs were diagnosed using CT scan.

Results

During this period, we identified 3.01 cases/1000 admissions. The mortality rate of the 77 included patients was 30 %. In multivariate analysis, we observed that mortality was independently associated with SAPS II (OR 1.1, 95 % CI [1.013–1.195], p = 0.02) and with the presence of hemorrhagic shock (OR 67.1, 95 % CI [2.6–1691], p = 0.01). We found IPH was related to anticoagulation therapy in 56 cases (72 %), with guideline-concordant reversal performed in 33 % of patients. We did not found any association between anticoagulant therapy type and outcome.

Conclusion

We found IPH is an infrequent disease, with a high mortality rate of 30 %, mostly related to anticoagulation therapy and usually affecting the elderly. Management of anticoagulation-related IPH includes a high rate of no reversal of 38 %.

Prehospital intravenous epinephrine may boost survival of patients with traumatic cardiac arrest: a retrospective cohort study

BACKGROUND

Prehospital resuscitation for patients with major trauma emphasizes a load-and-go principle. For traumatic cardiac arrest (TCA) patients, the administration of vasopressors remains under debate. This study evaluated the effectiveness of epinephrine in the prehospital setting for patients with TCA.

METHODS

We conducted a retrospective cohort study using a prospectively collected registry for out-of-hospital cardiac arrest in Taipei. Enrollees were ≥18 years of age with TCA. Patients with signs of obvious death like decapitation or rigor mortis were excluded. Patients were grouped according to prehospital administration, or lack thereof, of epinephrine. Outcomes were sustained (≥2 h) recovery of spontaneous circulation (ROSC) and survival to discharge. A subgroup analysis was performed by stratified total prehospital time.

RESULTS

From June 1 2010 to May 31 2013, 514 cases were enrolled. Epinephrine was administered in 43 (8.4%) cases. Among all patients, sustained ROSC and survival to discharge was 101 (19.6%) and 20 (3.9%), respectively. The epinephrine group versus the non-epinephrine group had higher sustained ROSC (41.9% vs. 17.6%, p < 0.01) and survival to discharge (14.0% vs. 3.0%, p < 0.01). The adjusted odds ratios (ORs) of epinephrine effect were 2.24 (95% confidence interval (CI) 1.05-4.81) on sustained ROSC, and 2.94 (95% CI 0.85-10.15) on survival to discharge. Subgroup analysis showed increased ORs of epinephrine effect on sustained ROSC with a longer prehospital time.

CONCLUSION

Among adult patients with TCA in an Asian metropolitan area, administration of epinephrine in the prehospital setting was associated with increased short-term survival, especially for those with a longer prehospital time.

"Smoker's Paradox" in Patients Treated for Severe Injuries: Lower Risk of Mortality After Trauma Observed in Current Smokers

BACKGROUND

Studies evaluating the effect of smoking status on mortality outcomes in trauma patients have been limited, despite the fact that survival benefits of smoking have been reported in other critical care settings. The phenomenon "smoker's paradox" refers to the observation that following acute cardiovascular events, such as acute myocardial infarction and cardiac arrest, smokers often experience decreased mortality in the hospital setting. The objective of our study was to determine whether smoking imparts a survival benefit in patients with traumatic injuries.

METHODS

We performed a retrospective cohort study that analyzed cases included in the National Trauma Data Bank research dataset. Hierarchical logistic regression analyses were used to determine whether smoking alters the risk of mortality and complications in patients who smoke.

RESULTS

The percentage of patients experiencing mortality differed significantly between smokers (n = 38,564) and nonsmokers (n = 319,249) (1.8% vs. 4.3%, P < .001); however, the percentage experiencing a major complication did not (9.7% vs. 9.6%, P = .763). Regression analyses indicated that smokers were significantly less likely to die during the hospital stay compared to nonsmokers after adjusting for individual and hospital factors (OR = 0.15; CI = 0.10, 0.22). Additionally, smokers were also less likely to develop a major complication than nonsmokers (OR = 0.73, CI = 0.59-0.91).

CONCLUSIONS

Patients who smoke appear to have a much lower risk of in-hospital mortality than nonsmokers. Further investigation into biological mechanisms responsible for this effect should be carried out in order to potentially develop therapeutic applications.

Clinical applications of biomedical microdevices for controlled drug delivery

Miniaturization of devices to micrometer and nanometer scales, combined with the use of biocompatible and functional materials, has created new opportunities for the implementation of drug delivery systems. Advances in biomedical microdevices for controlled drug delivery platforms promise a new generation of capabilities for the treatment of acute conditions and chronic illnesses, which require high adherence to treatment, in which temporal control over the pharmacokinetic profiles is critical. In addition, clinical conditions that require a combination of drugs with specific pharmacodynamic profiles and local delivery will benefit from drug delivery microdevices. This review provides a summary of various clinical applications for state-of-the-art controlled drug delivery microdevices, including cancer, endocrine and ocular disorders, and acute conditions such as hemorrhagic shock. Regulatory considerations for clinical translation of drug delivery microdevices are also discussed. Drug delivery microdevices promise a remarkable gain in clinical outcomes and a substantial social impact. A review of articles covering the field of microdevices for drug delivery was performed between January 1, 1990, and January 1, 2014, using PubMed as a search engine.

Vasopressin in hemorrhagic shock: a systematic review and meta-analysis of randomized animal trials

Objective. The latest European guidelines for the management of hemorrhagic shock suggest the use of vasopressors (norepinephrine) in order to restore an adequate mean arterial pressure when fluid resuscitation therapy fails to restore blood pressure. The administration of arginine vasopressin (AVP), or its analogue terlipressin, has been proposed as an alternative treatment in the early stages of hypovolemic shock. Design. A meta-analysis of randomized controlled animal trials. Participants. A total of 433 animals from 15 studies were included. Interventions. The ability of AVP and terlipressin to reduce mortality when compared with fluid resuscitation therapy, other vasopressors (norepinephrine or epinephrine), or placebo was investigated. Measurements and Main Results. Pooled estimates showed that AVP and terlipressin consistently and significantly improve survival in hemorrhagic shock (mortality: 26/174 (15%) in the AVP group versus 164/259 (63%) in the control arms; OR = 0.09; 95% CI 0.05 to 0.15; P for effect < 0.001; P for heterogeneity = 0.30; I₂ = 14%). Conclusions. Results suggest that AVP and terlipressin improve survival in the early phases of animal models of hemorrhagic shock. Vasopressin seems to be more effective than all other treatments, including other vasopressor drugs. These results need to be confirmed by human clinical trials.

[Indication: scientific and ethical basis of medical practice]

The medical indication provides a rational foundation for treatment decisions. An indication can be defined as the reasonable professional judgement that a medical procedure is suitable and useful to reach a specific therapeutic goal with a certain probability. An indication includes empirical, causal and purposive considerations and justifications, and a scrutiny of the individual case. This ensures that medical aspects of the patient, therapeutic goals and evidence-based knowledge are integrated and represented in the indication. An indication justifies a treatment proposal to the patient, which may only be carried out after a procedure of informed consent. Indications can be considered as the ethical basis of treatment decisions and as the heart of professionalism: indications should be used as a professional tool to protect against irrational therapeutic expectations, while ensuring the patient's right for reasonable treatment. In health care that is increasingly shaped by economic constraints, conscientious indications ensure the professional and ethical basis of medical treatment decisions.