Review article: Part one: Goal-directed resuscitation--which goals? Haemodynamic targets

Overtransfusion of packed red blood cells during massive transfusion activation: a potential quality metric for trauma resuscitation

Objectives

The goal of this study was to explore the incidence of overtransfusion in trauma patients requiring massive transfusion protocol (MTP) activation and identify modifiable risk factors. We hypothesized that overtransfusion is common after MTP activation.

Methods

Patients admitted to a level I trauma center from July 2016 to December 2019 and who required MTP activation were selected. The primary outcome was overtransfusion, defined as a hemoglobin (Hg) ≥11 g/dL at 24 hours (±2 hours). A Cox regression model was used to identify independent risk factors for overtransfusion.

Results

140 patients met inclusion criteria. The median age was 39.0 years, with the majority (74.3%) being male. The median (IQR) Injury Severity Score (ISS) was 24.0 (58.0) and 38.4% had a penetrating mechanism. The median (IQR) admission Hg was 12.6 (11.7) g/dL. Overall, 71.4% of patients were overtransfused by the conclusion of MTP, 43.6% 24 hours later, and 29.5% at discharge. Overtransfusion did not correlate with the number of units of blood transfused nor with the duration of MTP. Overtransfused patients at 24 hours after the conclusion of MTP were significantly more likely to present with a penetrating injury (52.5% vs. 27.3%, p=0.003) and have a significantly lower ISS (median (IQR) 18.5 (44.0) vs. 26.0 (58.0), p=0.035.) In a Cox regression model, penetrating mechanism (adjusted HR (AHR): 2.93; adjusted p=0.004) and admission base excess (BE) (AHR: 1.15; adjusted p=0.001) were the only variables independently associated with overtransfusion.

Conclusions

Overtransfusion of trauma patients requiring MTP activation is highly common, leading to overutilization of a limited resource. Penetrating trauma and BE may be modifiable risk factors that can help limit overtransfusion. Overtransfusion should be tracked as a data point by blood banks and trauma centers and be further studied as a potential quality metric for the resuscitation of massively transfused trauma patients.

Level of evidence

III.

Utilization and Efficacy of Resuscitation Endpoints in Trauma and Burn Patients: A Review Article

Shock is a sequelae in trauma and burn patients that substantially increases the risk for morbidity and mortality. The use of resuscitation endpoints allows for improved management of these patients, with the potential to prevent further morbidity/mortality. We conducted a review of the current literature on the efficacy of hemodynamic, metabolic, and regional resuscitation endpoints for use in trauma and burn patients. Hemodynamic endpoints included mean arterial pressure (MAP), heart rate (HR), urinary output (UO), compensatory reserve index (CRI), intrathoracic blood volume, and stroke volume variation (SVV). Metabolic endpoints measure cellular responses to decreased oxygen delivery and include serum lactic acid (LA), base deficit (BD), bicarbonate, anion gap, apparent strong ion difference, and serum pH. Mean arterial pressure, HR, UO, and LA are the most established markers of trauma and burn resuscitation. The evidence suggests LA is a superior metabolic endpoint marker. Newer resuscitation endpoint technologies such as point-of-care ultrasound (PoCUS), thromboelastography (TEG), and rotational thromboelastometry (ROTEM) may improve patient outcomes; however, additional research is needed to establish the efficacy in trauma and burn patients. The endpoints discussed have situational strengths and weaknesses and no single universal resuscitation endpoint has yet emerged. This review may increase knowledge and aid in guideline development. We recommend clinicians continue to integrate multiple endpoints with emphasis on MAP, HR, UO, LA, and BD. Future investigation should aim to standardize endpoints for each clinical presentation. The search for universal and novel resuscitation parameters in trauma and burns should also continue.

A Quantitative Study of the Dimensional Change of Inferior Vena Cava on Computed Tomography During Acute Hemorrhage Shock in Swine

Background: The purpose of this study was to examine the dimensional change of IVC during acute hemorrhage through a volume-controlled acute hemorrhagic shock model in swine. Methods: Volume-controlled hemorrhage was performed in 10 adult Bama mini pigs. Enhanced CT scan and hemodynamic monitoring were performed when the cumulative blood loss volume reached 0%, 10%, 20%, 30%, and 40%. The transverse diameter (T) and anteroposterior diameter (AP) of IVC were measured in axial images. Hemodynamic parameters were obtained with Pulse Contour Cardiac Output (PiCCO) hemodynamic monitor device. Arterial blood samples were also collected for artery blood gas analysis at each time point. Results: As the blood loss volume increased, the collapsibility (T/AP) and cross section area (CSA) of IVC significantly changed first in hepatic level and pre-renal level. The significant decrease of the CSA of IVC (shrink) occurred early when the blood loss volume reached only 10%, but the collapse of IVC occurred until the blood loss volume reached 30%. Conclusions: IVC shrank early but collapsed late during the acute hemorrhage in swine. The finding of collapsed IVC on CT scans suggested severe hypovolemic shock. Evaluation of the IVC at the CT scans can be an adjunctive test of the hemodynamic status in trauma patients.

Sources of inaccuracy in the measurement of adult patients' resting blood pressure in clinical settings: a systematic review

BACKGROUND

To interpret blood pressure (BP) data appropriately, healthcare providers need to be knowledgeable of the factors that can potentially impact the accuracy of BP measurement and contribute to variability between measurements.

METHODS

A systematic review of studies quantifying BP measurement inaccuracy. Medline and CINAHL databases were searched for empirical articles and systematic reviews published up to June 2015. Empirical articles were included if they reported a study that was relevant to the measurement of adult patients' resting BP at the upper arm in a clinical setting (e.g. ward or office); identified a specific source of inaccuracy; and quantified its effect. Reference lists and reviews were searched for additional articles.

RESULTS

A total of 328 empirical studies were included. They investigated 29 potential sources of inaccuracy, categorized as relating to the patient, device, procedure or observer. Significant directional effects were found for 27; however, for some, the effects were inconsistent in direction. Compared with true resting BP, significant effects of individual sources ranged from -23.6 to +33 mmHg SBP and -14 to +23 mmHg DBP.

CONCLUSION

A single BP value outside the expected range should be interpreted with caution and not taken as a definitive indicator of clinical deterioration. Where a measurement is abnormally high or low, further measurements should be taken and averaged. Wherever possible, BP values should be recorded graphically within ranges. This may reduce the impact of sources of inaccuracy and reduce the scope for misinterpretations based on small, likely erroneous or misleading, changes.

A Review of Central Venous Pressure and Its Reliability as a Hemodynamic Monitoring Tool in Veterinary Medicine

OBJECTIVE

To review the current literature regarding central venous pressure (CVP) in veterinary patients pertaining to placement (of central line), measurement, interpretation, use in veterinary medicine, limitations, and controversies in human medicine.

ETIOLOGY

CVP use in human medicine is a widely debated topic, as numerous sources have shown poor correlation of CVP measurements to the volume status of a patient. Owing to the ease of placement and monitoring in veterinary medicine, CVP remains a widely used modality for evaluating the hemodynamic status of a patient. A thorough evaluation of the veterinary and human literature should be performed to evaluate the role of CVP measurements in assessing volume status in veterinary patients.

DIAGNOSIS

Veterinary patients that benefit from accurate CVP readings include those suffering from hypovolemic or septic shock, heart disease, or renal disease or all of these. Other patients that may benefit from CVP monitoring include high-risk anesthetic patients undergoing major surgery, trending of fluid volume status in critically ill patients, patients with continued shock, and patients that require rapid or large amounts of fluids.

THERAPY

The goal of CVP use is to better understand a patient's intravascular volume status, which would allow early goal-directed therapy.

PROGNOSIS

CVP would most likely continue to play an important role in the hemodynamic monitoring of the critically ill veterinary patient; however, when available, cardiac output methods should be considered the first choice for hemodynamic monitoring.

Fluid resuscitation therapy for paediatric sepsis

Sepsis and septic shock are the final common pathway for many decompensated paediatric infections. Fluid resuscitation therapy has been the cornerstone of haemodynamic resuscitation in these children. Good evidence for equivalence between 0.9% saline and 4% albumin, with the relative expense of the latter, has meant that 0.9% saline is currently the most commonly used resuscitation fluid world-wide. Evidence for harm from the chloride load in 0.9% saline has generated interest in balanced solutions as first line resuscitation fluids. Their safety has been well established in observational studies, and they may well be the most reasonable default fluid for resuscitation. Semi-synthetic colloids have been associated with renal dysfunction and death and should be avoided. There is evidence for harm from excessive administration of any resuscitation fluid. Resuscitation fluid volumes should be treated in the same way as the dose of any other intravenously administered medication, and the potential benefits versus harms for the individual patient weighed prior to administration.

The effect of pH versus base deficit on organ failure in trauma patients

BACKGROUND

Base deficit (BD) calculations are affected by trauma-related changes in circulating concentrations of anions after injury. In contrast, pH is a direct measurement that corresponds to hypoperfusion. We hypothesized that changes in pH would more closely correspond to organ dysfunction compared with changes in BD.

MATERIALS AND METHODS

BD and pH values were collected for the first 48 h after injury from a retrospective cohort of 74 multiply injured adult patients who were admitted to the surgical intensive care unit for a minimum of 1 wk. Mean and extreme (minimum pH and maximum BD) values of pH and BD were determined for day 1 (0-24 h) and for day 2 (24-48 h) after injury. Organ dysfunction was measured by averaging daily sequential organ failure assessment scores over the entire duration of intensive care unit admission. BD and pH values were compared with mean modified sequential organ failure assessment scores by univariate and multivariate linear regression.

RESULTS

Organ dysfunction corresponded more closely with changes in pH compared with those in BD. Minimum pH and maximum BD showed better correspondence to organ dysfunction compared with mean values. Minimum pH values at 24-48 h had the highest univariate (r(2) = 0.43) correspondence to organ dysfunction. In contrast, mean BD values at 24-48 h showed no correspondence (r(2) = 0.07) to organ dysfunction. Multivariate analysis demonstrated that 24-48 h of minimum pH had the highest numerical effect on organ dysfunction.

CONCLUSIONS

Correspondence between organ dysfunction and BD deteriorated in contrast to increasing correspondence between organ dysfunction and pH measured within 48 h after injury.

Optimal fluid resuscitation in trauma: type, timing, and total

PURPOSE OF REVIEW

This review article explores the recent literature regarding the optimal type and amount of intravenous fluids for the trauma patient from the time of injury through their ICU stay. It discusses damage control principles as well as targeted resuscitation utilizing new technology.

RECENT FINDINGS

In the prehospital arena, intravenous fluids have been associated with worse patient outcomes due to increased coagulopathy and time to definitive care. Once in the trauma bay, damage control resuscitation principles apply to the severely injured patient. Large volume crystalloid infusion increases mortality. The best patient outcomes have been found with transfusion of blood products in a ratio that closely mimics whole blood. Thrombelastography is a useful adjunct in resuscitation and can help guide the judicious use of blood products. New technology can help providers ascertain when a patient is appropriately resuscitated by determining adequate global and regional perfusion.

SUMMARY

During the resuscitation of the acutely injured patient, crystalloids should be limited in favor of blood components. Damage control principles apply until definitive hemostasis is obtained, at which point the focus should change to targeted resuscitation using traditional global endpoints of resuscitation in conjunction with determinants of regional perfusion.

Findings of a randomized controlled trial using limited transthoracic echocardiogram (LTTE) as a hemodynamic monitoring tool in the trauma bay

BACKGROUND

We hypothesize that limited transthoracic echocardiogram (LTTE) is a useful tool to guide therapy during the initial phase of resuscitation in trauma patients.

METHODS

All highest-level alert patients with at least one measurement of systolic blood pressure less than 100 mm Hg, a mean arterial pressure less than 60 mm Hg, and/or a heart rate greater than 120 beats per minute who arrived to the trauma bay (TB) were randomized to have either LTTE performed (LTTEp) or not performed (non-LTTE) as part of their initial evaluation. Images were stored, and results were reported regarding contractility (good vs. poor), fluid status (empty inferior vena cava [hypovolemic] vs. full inferior vena cava [not hypovolemic]), and pericardial effusion (present vs. absent). Time from TB to operating room, intravenous fluid administration, blood product requirement, intensive care unit admission, and mortality were examined in both groups.

RESULTS

A total of 240 patients were randomized. Twenty-five patients were excluded since they died upon arrival to the TB, leaving 215 patients in the study. Ninety-two patients were in the LTTEp group with 123 patients in the non-LTTE group. The LTTEp and non-LTTE groups were similar in age (38 years vs. 38.8 years, p = 0.75), Injury Severity Score (ISS) (19.2 vs. 19.0, p = 0.94), Revised Trauma Score (RTS) (5.5 vs. 6.0, p = 0.09), lactate (4.2 vs. 3.6, p = 0.14), and mechanism of injury (p = 0.44). Strikingly, LTTEp had significantly less intravenous fluid than non-LTTE patients (1.5 L vs. 2.5 L, p < 0.0001), less time from TB to operating room (35.6 minutes vs. 79.1 min, p = 0.0006), higher rate of intensive care unit admission (80.4% vs. 67.2%, p = 0.04), and a lower mortality rate (11% vs. 19.5%, p = 0.09). Mortality differences were particularly evident in the traumatic brain injury patients (14.7% in LTTEp vs. 39.5% in non-LTTE, p = 0.03).

CONCLUSION

LTTE is a useful guide for therapy in hypotensive trauma patients during the early phase of resuscitation.

LEVEL OF EVIDENCE

Therapeutic study, level II.