The impact of opioid administration on resuscitation volumes in thermally injured patients

Regional Burn Review: Neither Parkland Nor Brooke Formulas Reach 85% Accuracy Mark for Burn Resuscitation

Prolonged resuscitation can result in burn wound conversion and other complications. Our team switched from using Parkland formula (PF) to the modified Brooke formula (BF) in January 2020. Secondary to difficult resuscitations using BF, we sought to review our data to identify factors associated with resuscitation requiring greater than predicted resuscitation with either formula, defined as 25% or more of predicted, hereafter referred to as over-resuscitation. Patients admitted to the burn unit between January 1, 2019 and August 29, 2021 for a burn injury with a percentage of total body surface area (%TBSA) ≥15% were included. Subjects <18 years, or weighing <30 kg, and those who died or had care withdrawn within 24 hours of admission were excluded. Demographics, injury information, and resuscitation information were collected. Univariate and multivariate analyses were performed to identify factors associated with over-resuscitation by either formula. P < .05 was considered significant. Sixty-four patients were included; 27 were resuscitated using BF and 37 using PF. No significant differences were observed in demographics and burn injury between the groups. Patients required a median of 3.59 ml/kg/%TBSA for BF and 3.99 ml/kg/%TBSA for PF to reach maintenance (P = .32). Over-resuscitation was more likely to occur when using BF compared to PF (59.3% vs 32.4%, P = .043). Over-resuscitation was associated with longer time to reach maintenance (OR = 1.179 [1.042-1.333], P = .009) and arrival via ground transportation (OR = 10.523 [1.171-94.597], P = .036). Future studies are warranted to identify populations in which BF under-performs and sequelae associated with prolonged resuscitation.

The risks of sedation and pain control during burn resuscitation: Increased opioids lead to over-resuscitation and hypotension

INTRODUCTION

Pain management and sedation are necessary in severely burned persons. Balancing pain control, obtundation, and hemodynamic suppression can be challenging. We hypothesized that increased sedation during burn resuscitation is associated with increased intravenous fluid administration and hemodynamic instability.

METHODS

A retrospective review of a single burn center was performed from 2014 to 2019 for all admissions to the burn unit with > 20% total body surface area (TBSA) burns. Within 48 h of admission, we compared total amounts of sedation/pain medications (morphine milligram equivalents (MME), propofol, dexmedetomidine, benzodiazepines) with total resuscitation volumes and frequency of hypotensive episodes. Resuscitation volumes and frequency of hypotension were modeled with multivariable linear regression adjusting for burn severity and weight.

RESULTS

208 patients were included with median age of 43 years (IQR 29-55) and median %TBSA of 31 (IQR 25-44). Median 48-hour resuscitation milliliters per weight per %TBSA were 3.3 (IQR 2.28-4.92). Pain/sedative medications included a combination of opioids in 99%, benzodiazepines in 73%, propofol in 31%, and dexmedetomidine in 11% of patients. MMEs were associated with greater resuscitation volumes (95% CI: 0.15-0.54, p = 0.01) as well as number of hypotensive events (95% CI: 1.57-2.7, p < 0.001). No associations were noted with other sedative medications when comparing the number of hypotensive events and resuscitation volumes.

CONCLUSIONS

Increased opioid administration has physiological consequences and should be carefully monitored during resuscitation as higher volume administrations lead to worse outcomes. Opioids and sedating medications should be titrated to the least amount needed to achieve reasonable comfort and sedation.

Plasma for burn shock resuscitation: is it time to go back to the future?

Patients with burn shock can be challenging to resuscitate. Burn shock produces a variety of physiologic derangements: Patients are hypovolemic from volume loss, have a increased systemic vascular resistance, and may have a depressed cardiac output depending on the extent of the thermal injury. Additionally, the burn wound produces a significant inflammatory cascade of events that contributes to the shock state. Fluid resuscitation is foundational for the initial treatment of burn shock. Typical resuscitation is with intravenous lactated Ringer's in accordance with well-established formulas based on burn wound size. In the past century, as therapies to treat thermal injuries were being developed, plasma was the fluid used for burn resuscitation; in fact, plasma was used in World War II and throughout the 1950s and 1960s. Plasma was abandoned because of infectious risks and complications. Despite huge strides in transfusion medicine and the increased safety of blood products, plasma has never been readopted for burn resuscitation. Over the past 15 years, there has been a paradigm shift in trauma resuscitation: Less crystalloid and more blood products are used; this strategy has demonstrated improved outcomes. Plasma is a physiologic fluid that stabilizes the endothelium. The endotheliopathy of trauma has been described and is mitigated by transfusion strategies with a 1:1 ratio of RBCs to plasma. Thermal injury also results in endothelial dysfunction: the endotheliopathy of burns. Plasma is likely a better resuscitation fluid for patients with significant burn wounds because of its capability to restore intravascular volume status and treat the endotheliopathy of burns.

Fluid resuscitation in paediatric burns: how do we get it right? A systematic review of the evidence

BACKGROUND

Optimal fluid resuscitation in children with major burns is crucial to prevent or minimise burn shock and prevent complications of over-resuscitation.

OBJECTIVES

To identify studies using endpoints to guide fluid resuscitation in children with burns, review the range of reported endpoint targets and assess whether there is evidence that targeted endpoints impact on outcome.

DESIGN

Systematic review.

METHODS

Medline, Embase, Cinahl and the Cochrane Central Register of Controlled Trials databases were searched with no restrictions on study design or date. Search terms combined burns, fluid resuscitation, endpoints, goal-directed therapy and related synonyms. Studies reporting primary data regarding children with burns (<16 years) and targeting fluid resuscitation endpoints were included. Data were extracted using a proforma and the results were narratively reviewed.

RESULTS

Following screening of 777 unique references, 7 studies fulfilled the inclusion criteria. Four studies were exclusively paediatric. Six studies used urine output (UO) as the primary endpoint. Of these, one set a minimum UO threshold, while the remainder targeted a range from 0.5-1.0 mL/kg/hour to 2-3 mL/kg/hour. No studies compared different UO targets. Heterogeneous study protocols and outcomes precluded comparison between the UO targets. One study targeted invasive haemodynamic variables, but this did not significantly affect patient outcome.

CONCLUSIONS

Few studies have researched resuscitation endpoints for children with burns. Those that have done so have investigated heterogeneous endpoints and endpoint targets. There is a need for future randomised controlled trials to identify optimal endpoints with which to target fluid resuscitation in children with burns.

Tracheostomy and mortality in patients with severe burns: A nationwide observational study

BACKGROUND

Tracheostomy is often performed in patients with severe burns who are undergoing prolonged mechanical ventilation. However, the appropriate timing of tracheostomy and its effect on mortality remain unknown. The aim of this study was to determine whether tracheostomy can reduce mortality in patients with severe burns.

METHODS

Using the Japanese Diagnosis Procedure Combination database from April 2010 to March 2014, we extracted data on adult patients with severe burns (burn index score of ≥15) who started mechanical ventilation within 3days of admission. We estimated the hazard ratio for 28-day in-hospital mortality associated with tracheotomy performed from day 5 to 28. We adjusted for baseline and time-dependent confounders using inverse probability of treatment weighting methods and fitted a marginal structural Cox proportional hazard model.

RESULTS

We identified 680 eligible patients (94 in the tracheostomy group, 2289 person-days; 586 in the non-tracheostomy group, 11,197 person-days). Patients who underwent a tracheostomy had worse prognostic factors for mortality. After adjustment for these factors, the hazard ratio for 28-day mortality associated with tracheostomy compared with non-tracheostomy was 0.73 (95% confidence interval, 0.39-1.34).

CONCLUSIONS

There was no significant association between 28-day in-hospital mortality and early tracheostomy in adult patients with severe burns.

Burn State of the Science: Fluid Resuscitation

Recognition of fluid creep has driven a large amount of the scientific investigation in the area of acute fluid resuscitation for burn patients. The role of colloids in ameliorating fluid creep is controversial, despite the fact that a fluid-sparing effect of colloids has been recognized for some time. All but one of the available prospective studies using colloids are more than a decade old, and a modern randomized controlled trial (RCT) comparing crystalloids to colloids is long overdue. While urinary output continues to be the main endpoint for fluid titration, there has been a moderate amount of interest in the use of transpulmonary thermodilution to guide fluid resuscitation. The available studies have found that transpulmonary thermodilution has had an inconsistent effect on limiting fluid resuscitation volumes and improving clinical outcomes. Computerized Decision Support Systems show great promise in optimizing fluid titration and reducing fluid resuscitation volumes, and an RCT comparing Computerized Decision Support Systems with conventional titration approaches will be the important next step. Use of high-dose vitamin C (ascorbic acid) has become a popular approach to limit fluid resuscitation volumes and edema formation, but it has been investigated in only two clinical studies: one a pseudo-randomized prospective study and the other a retrospective study. Improvements in clinical outcome have not been convincingly demonstrated, and concerns persist surrounding the possibility of induction of an osmotic diuresis, leading to intravascular volume depletion. An RCT is urgently required to evaluate high-dose vitamin C as an adjunct to crystalloid resuscitation compared with the use of crystalloids alone.

Hemodynamic responses to dexmedetomidine in critically injured intubated pediatric burned patients: a preliminary study

Because of ineffectiveness and tolerance to benzodiazepines and opioids developing with time, drugs acting via other receptor systems (eg, α-2 agonists) have been advocated in burn patients to improve sedation and analgesia. This study in severely burned pediatric subjects examined the hemodynamic consequences of dexmedetomidine (Dex) administration. Eight intubated patients with ≥20 to 79% TBSA burns were studied between 7 and 35 days after injury. After baseline measurements of mean arterial blood pressure and heart rhythm were taken, each patient received a 1.0 µg/kg bolus of Dex followed by an ascending dose infusion protocol (0.7-2.5 µg/kg/hr), with each dose administered for 15 minutes. There was significant hypotension (27±7.5%, average drop in mean arterial pressure [MAP] ± SD), and a decrease in heart rate (HR; 19% ± 7, average drop in HR ± SD). The average HR decreased from 146 beats per minute to 120. No bradycardia (HR < 60) or heart blocks were observed. In three patients, the MAP decreased to <50mm Hg with the bolus dose of Dex. Of the remaining five patients, three patients completed the study receiving the highest infusion dose of Dex (2.5 µg/kg/hr), whereas in 2 patients the infusion part of the study was begun, but the study was stopped due to persistent hypotension (MAP < 50mm Hg). These observations indicate that a bolus dose of Dex (1.0 µg/kg for 10 minutes) and high infusion rates may require fluid resuscitation or vasopressor support to maintain normotension in critically injured pediatric burn patients.

Burn injuries

PURPOSE OF REVIEW

To summarize and highlight recent advances in the understanding and management of burn injuries.

RECENT FINDINGS

The review focuses on topics which are of particular relevance for critical care practitioners involved in burn care: resuscitation, management of infection and sepsis, epidemiology and outcome, and organization and costs of burn care.

SUMMARY

While being the mainstay of early survival in burn victims, various aspects of burn resuscitation are still contentious and highlighted in this review. In particular, several strategies to overcome the repeatedly observed 'fluid creep' in burn patients are discussed, including the use of computerized resuscitation algorithms and the administration of colloids. Sepsis and multiorgan failure have become the major causes of death in patients surviving the initial phase of burn shock. Various aspects of sepsis management are reviewed, amongst which diagnosis, antibiotic treatment and prophylaxis. Recent epidemiologic data allow to identify risk factors associated with mortality as these are potentially amenable to targeted prevention and therapy. Examples are acute kidney injury and sepsis. The overview is completed by recent findings on organization and costs of burn care, including the adherence to referral criteria and the main determinants of cost.

Review of burn research for the year 2010

Like the previous year, 2010 was another active year for research in burn care. For this year, more than 1200 burn-related articles were published on a diverse array of topics. In this review, we focus on innovative and impactful burn injury-related research. As in the previous review, we group articles according to the following categories: critical care, infection, inhalation injury, epidemiology, psychology, wound characterization and treatment, nutrition and metabolism, pain and itch management, burn reconstruction, and rehabilitation. We have found that burn research continues to be prolific throughout the world and reflects the wide-ranging and complex care requirements of burn survivors.

Evolving changes in the management of burns and environmental injuries

Burns and environmental injuries are common as primary or secondary problems in survivors of natural disasters, terrorist incidents, and combat operations. In recent years, intensive military medical experience has resulted in substantial progress in treatment of these important problems. This article reviews practical applications of this new knowledge.

Harborview burns--1974 to 2009

BACKGROUND

Burn demographics, prevention and care have changed considerably since the 1970s. The objectives were to 1) identify new and confirm previously described changes, 2) make comparisons to the American Burn Association National Burn Repository, 3) determine when the administration of fluids in excess of the Baxter formula began and to identify potential causes, and 4) model mortality over time, during a 36-year period (1974-2009) at the Harborview Burn Center in Seattle, WA, USA.

METHODS AND FINDINGS

14,266 consecutive admissions were analyzed in five-year periods and many parameters compared to the National Burn Repository. Fluid resuscitation was compared in five-year periods from 1974 to 2009. Mortality was modeled with the rBaux model. Many changes are highlighted at the end of the manuscript including 1) the large increase in numbers of total and short-stay admissions, 2) the decline in numbers of large burn injuries, 3) that unadjusted case fatality declined to the mid-1980s but has changed little during the past two decades, 4) that race/ethnicity and payer status disparity exists, and 5) that the trajectory to death changed with fewer deaths occurring after seven days post-injury. Administration of fluids in excess of the Baxter formula during resuscitation of uncomplicated injuries was evident at least by the early 1990s and has continued to the present; the cause is likely multifactorial but pre-hospital fluids, prophylactic tracheal intubation and opioids may be involved.

CONCLUSIONS

1) The dramatic changes include the rise in short-stay admissions; as a result, the model of burn care practiced since the 1970s is still required but is no longer sufficient. 2) Fluid administration in excess of the Baxter formula with uncomplicated injuries began at least two decades ago. 3) Unadjusted case fatality declined to ∼6% in the mid-1980s and changed little since then. The rBaux mortality model is quite accurate.

The year in burns 2010

For 2010, roughly 1446 original burn research articles were published in scientific journals using the English language. This article reviews those with the most impact on burn treatment according to the Editor of one of the major journals (Burns) and his colleagues. As in previous reviews, articles were divided into the following topic areas: epidemiology, demographics of injury, wound characterisation and treatment, critical care, inhalation injury, infection, metabolism and nutrition, psychological considerations, pain and itching management, rehabilitation and long-term outcomes, and burn reconstruction. Each paper is considered very briefly, and the reader is referred to full manuscripts for details.

Burn resuscitation

Fluid resuscitation following burn injury must support organ perfusion with the least amount of fluid necessary and the least physiological cost. Under resuscitation may lead to organ failure and death. With adoption of weight and injury size-based formulas for resuscitation, multiple organ dysfunction and inadequate resuscitation have become uncommon. Instead, administration of fluid volumes well in excess of historic guidelines has been reported. A number of strategies including greater use of colloids and vasoactive drugs are now under investigation to optimize preservation of end organ function while avoiding complications which can include respiratory failure and compartment syndromes. Adjuncts to resuscitation, such as antioxidants, are also being investigated along with parameters beyond urine output and vital signs to identify endpoints of therapy. Here we briefly review the state-of-the-art and provide a sample of protocols now under investigation in North American burn centers.