Association between hydroxocobalamin administration and acute kidney injury after smoke inhalation: a multicenter retrospective study

Time to Burn? Characteristics of Hydroxocobalamin Administration in an Academic Medical Center

Background/Objective: Hydroxocobalamin is indicated for cyanide poisoning and its package insert states it should be given "without delay". We sought to evaluate time to administration and clinical characteristics when hydroxocobalamin was administered in a quaternary care academic medical center. Methods: All hydroxocobalamin administrations from January 1, 2007 to December 31, 2018 were analyzed. Data points recorded were: carboxyhemoglobin, cyanide and methemoglobin levels, hospital time and course, time and dose of hydroxocobalamin administration, lactate and bicarbonate levels, initial and nadir pH, initial heart rate, and initial and lowest systolic blood pressure. Results: Fifty-six cases were identified. One case was excluded as hydroxocobalamin was administered for nitroprusside toxicity. Among 55 cases analyzed, 93% (n = 51) were adults. Median hospital length of stay was 4.3 days (IQR 2.5 to 12). Burn, inhalation injury, and smoke inhalation were 80% of admitting diagnoses. Median time to hydroxocobalamin administration was 208 minutes (IQR 62.5 to 330). Eleven of 55 cases died. Hydroxocobalamin was given within 60 minutes of arrival in 12 cases, of which 3 died. All adults received 5 g of hydroxocobalamin. Time to hydroxocobalamin administration was longer in death cases [median: 221 minutes (IQR 119 to 594)] vs survivors [median: 184.5 minutes (IQR 62.8 to 315)]. Seventeen cases had cyanide levels drawn, with 9 being measurable, but none were toxic. Conclusions: Significant delay in hydroxocobalamin administration was seen in this study. Cases that resulted in death had significantly longer times to hydroxocobalamin administration. Further studies are warranted to identify reasons for delays in hydroxocobalamin administration.

Inhalation Injury, Respiratory Failure, and Ventilator Support in Acute Burn Care

Sustaining an inhalation injury increases the risk of severe complications and mortality. Current evidential support to guide treatment of the injury or subsequent complications is lacking, as studies either exclude inhalation injury or design limit inferences that can be made. Conventional ventilator modes are most commonly used, but there is no consensus on optimal strategies. Settings should be customized to patient tolerance and response. Data for pharmacotherapy adjunctive treatments are limited.

Acute kidney injury in patients with burns

Burn injury is associated with a high risk of acute kidney injury (AKI) with a prevalence of AKI among patients with burns of 9-50%. Despite an improvement in burn injury survival in the past decade, AKI in patients with burns is associated with an extremely poor short-term and long-term prognosis, with a mortality of >80% among those with severe AKI. Factors that contribute to the development of AKI in patients with burns include haemodynamic alterations, burn-induced systemic inflammation and apoptosis, haemolysis, rhabdomyolysis, smoke inhalation injury, drug nephrotoxicity and sepsis. Early and late AKI after burn injury differ in their aetiologies and outcomes. Sepsis is the main driver of late AKI in patients with burns and late AKI has been associated with higher mortality than early AKI. Prevention of early AKI involves correction of hypovolaemia and avoidance of nephrotoxic drugs (for example, hydroxocobalamin), whereas prevention of late AKI involves prevention and early recognition of sepsis as well as avoidance of nephrotoxins. Treatment of AKI in patients with burns remains supportive, including prevention of fluid overload, treatment of electrolyte disturbance and use of kidney replacement therapy when indicated.

Adverse Clinical Effects Associated With Non-catecholamine Pharmacologic Agents for Treatment of Vasoplegic Syndrome in Adult Cardiac Surgery

Vasoplegic syndrome is a relatively common complication that can happen during and after major adult cardiac surgery. It is associated with a higher rate of complications, including postoperative renal failure, longer duration of mechanical ventilation, and intensive care unit stay, as well as increased mortality. The underlying pathophysiology of vasoplegic syndrome is that of profound vascular hyporesponsiveness, and involves a complex interplay among inflammatory cytokines, cellular surface receptors, and nitric oxide (NO) production. The pharmacotherapy approaches for the treatment of vasoplegia include medications that increase vascular smooth muscle contraction via increasing cytosolic calcium in myocytes, reduce the vascular effects of NO and inflammation, and increase the biosynthesis of and vascular response to norepinephrine. Clinical trials have demonstrated the clinical efficacy of non-catecholamine pharmacologic agents in the treatment of vasoplegic syndrome. With an increase in their use today, it is important for clinicians to understand the adverse clinical outcomes and patient risk profiles associated with these agents, which will allow better-tailored medical therapy.

Evaluation of hydroxocobalamin use for the treatment of suspected cyanide toxicity secondary to smoke inhalation

Hydroxocobalamin is used for cyanide toxicity after smoke inhalation, but diagnosis is challenging. Retrospective studies have associated hydroxocobalamin with acute kidney injury (AKI). This is a retrospective analysis of patients receiving hydroxocobalamin for suspected cyanide toxicity. The primary outcome was the proportion of patients meeting predefined appropriate use criteria defined as ≥1 of the following: serum lactate ≥8 mmol/L, systolic blood pressure (SBP) <90 mmHg, new-onset seizure, cardiac arrest, or respiratory arrest. Secondary outcomes included incidence of AKI, pneumonia, resolution of initial neurologic symptoms, and in-hospital mortality. Forty-six patients were included; 35 (76%) met the primary outcome. All met appropriate use criteria due to respiratory arrest, 15 (43%) for lactate, 14 (40%) for SBP, 12 (34%) for cardiac arrest. AKI, pneumonia, and resolution of neurologic symptoms occurred in 30%, 21%, and 49% of patients, respectively. In-hospital mortality was higher in patients meeting criteria, 49% vs. 9% (95% CI 0.16, 0.64). When appropriate use criteria were modified to exclude respiratory arrest in a post-hoc analysis, differences were maintained, suggesting respiratory arrest alone is not a critical component to determine hydroxocobalamin administration. Predefined appropriate use criteria identify severely ill smoke inhalation victims and provides hydroxocobalamin treatment guidance.

Angiotensin-II for vasoplegia following cardiac surgery

INTRODUCTION

The objective of this study was to describe the implementation and outcomes of a protocol outlining angiotensin-II utilization for vasoplegia following cardiac surgery.

METHODS

This was a retrospective chart review at a single-center university hospital. Included patients received angiotensin-II for vasoplegia refractory to standard interventions, including norepinephrine 20 mcg/min and vasopressin 0.04 units/min, following cardiac surgery between April 2021 and April 2022.

RESULTS

30 patients received angiotensin-II for refractory vasoplegia. Adjunctive agents at angiotensin-II initiation included corticosteroids (26 patients; 87%), epinephrine (26 patients; 87%), dobutamine (17 patients; 57%), dopamine (9 patients; 30%), milrinone (2 patients; 7%), and hydroxocobalamin (4 patients; 13%). At 3 hours, the median mean arterial pressure increased from baseline (70 vs 61.5 mmHg, p = .0006). Median norepinephrine doses at angiotensin-II initiation, 1 hour, 3 hours, and angiotensin-II discontinuation were 0.22, 0.16 (p = .0023), 0.10 (p < .0001), and 0.07 (p < .0001) mcg/kg/min. Median dobutamine doses decreased throughout angiotensin-II infusion from eight to six mcg/kg/min (p = .0313). Other vasoactive medication doses were unchanged. Three patients (10%) subsequently received hydroxocobalamin. Thirteen (43.3%) and five (16.7%) patients experienced mortality by day 28 and venous or arterial thrombosis events, respectively.

CONCLUSIONS

The administration of angiotensin-II to vasoplegic patients following cardiac surgery was associated with increased mean arterial pressure, reduced norepinephrine dosages, and reduced dobutamine dosages.

Adrenal Emergencies

The adrenal glands drive physiologic homeostasis, with dysregulation in any direction causing multisystem dysfunction. Adrenal excess states include hyperaldosteronism which manifests with refractory hypertension and electrolyte abnormalities including hypernatremia and hypokalemia. Paragangliomas including pheochromocytoma can cause multisystem end-organ dysfunction due to catecholaminergic storm, which require rapid blood pressure control with phentolamine and identification of lesions amenable to surgical resection. Adrenal insufficiency states in contrast can result in hypotension and decompensation refractory to vasopressor administration, requiring adrenal supplementation via hydrocortisone.

Choosing wisely in burn care

BACKGROUND

The Choosing Wisely Campaign was launched in 2012 and has been applied to a broad spectrum of disciplines in almost thirty countries, with the objective of reducing unnecessary or potentially harmful investigations and procedures, thus limiting costs and improving outcomes. In Canada, patients with burn injuries are usually initially assessed by primary care and emergency providers, while plastic or general surgeons provide ongoing management. We sought to develop a series of Choosing Wisely statements for burn care to guide these practitioners and inform suitable, cost-effective investigations and treatment choices.

METHODS

The Choosing Wisely Canada list for Burns was developed by members of the Canadian Special Interest Group of the American Burn Association. Eleven recommendations were generated from an initial list of 29 statements using a modified Delphi process and SurveyMonkey™.

RESULTS

Recommendations included statements on avoidance of prophylactic antibiotics, restriction of blood products, use of adjunctive analgesic medications, monitoring and titration of opioid analgesics, and minimizing 'routine' bloodwork, microbiology or radiological investigations.

CONCLUSIONS

The Choosing Wisely recommendations aim to encourage greater discussion between those involved in burn care, other health care professionals, and their patients, with a view to reduce the cost and adverse effects associated with unnecessary therapeutic and diagnostic procedures, while still maintaining high standards of evidence-based burn care.

No sex differences in the incidence, risk factors and clinical impact of acute kidney injury in critically ill patients with sepsis

Background

Sex-stratified medicine is an important aspect of precision medicine. We aimed to compare the incidence and risk factors of acute kidney injury (AKI) for critically ill men and women with sepsis. Furthermore, the short-term mortality was compared between men and women with sepsis associated acute kidney injury (SA-AKI).

Method

This was a retrospective study based on the Medical Information Mart for Intensive Care IV database. We used the multivariable logistic regression analysis to evaluate the independent effect of sex on the incidence of SA-AKI. We further applied three machine learning methods (decision tree, random forest and extreme gradient boosting) to screen for the risk factors associated with SA-AKI in the total, men and women groups. We finally compared the intensive care unit (ICU) and hospital mortality between men and women with SA-AKI using propensity score matching.

Results

A total of 6463 patients were included in our study, including 3673 men and 2790 women. The incidence of SA-AKI was 83.8% for men and 82.1% for women. After adjustment for confounders, no significant association was observed between sex and the incidence of SA-AKI (odds ratio (OR), 1.137; 95% confidence interval (CI), 0.949-1.361; p=0.163). The machine learning results revealed that body mass index, Oxford Acute Severity of Illness Score, diuretic, Acute Physiology Score III and age were the most important risk factors of SA-AKI, irrespective of sex. After propensity score matching, men had similar ICU and hospital mortality to women.

Conclusions

The incidence and associated risk factors of SA-AKI are similar between men and women, and men and women with SA-AKI experience comparable rates of ICU and hospital mortality. Therefore, sex-related effects may play a minor role in developing SA-AKI. Our study helps to contribute to the knowledge gap between sex and SA-AKI.

When the Renal (Function) Begins to Fall: A Mini-Review of Acute Kidney Injury Related to Acute Respiratory Distress Syndrome in Critically Ill Patients

Acute kidney injury (AKI) is one of the most frequent causes of organ failure encountered in patients in the intensive care unit (ICU). Because of its predisposition to occur in the most critically ill patients, it is not surprising to observe a high frequency of AKI in patients with acute respiratory distress syndrome (ARDS). However, few studies have been carried out to assess the epidemiology of AKI in subgroups of ARDS patients using recommended KDIGO criteria. Moreover, the mechanisms involved in the physio-pathogenesis of AKI are still poorly understood, in particular the impact of mechanical ventilation on the kidneys. We carried out a review of the literature, focusing on the epidemiology and physiopathology of AKI in patients with ARDS admitted to the ICU. We addressed the importance of clinical management, focusing on mechanical ventilation for improving outcomes, on AKI. Finally, we also propose candidate treatment strategies and management perspectives. Our literature search showed that AKI is particularly common in ICU patients with ARDS. In association with the classic risk factors for AKI, such as comorbidities and iatrogeny, changes in mechanical ventilation parameters, which have been exclusively evaluated for their outcomes on respiratory function and death, must be considered carefully in terms of their impact on the short-term renal prognosis.

Is intensive care unit mortality a valid survival outcome measure related to critical illness?

RATIONALE

Use of death as an outcome of intensive care unit (ICU) admission may be biased by differential discharge decisions.

OBJECTIVE

To determine the validity of ICU survival status as an outcome measure of all cause case-fatality.

METHODS

A retrospective cohort of first admissions among adults to four ICUs in North Brisbane, Australia was assembled. Death in ICU (censored at discharge or 30 days) was compared with 30-day overall case-fatality.

RESULTS

The 30-day overall case-fatality was 8.1% (2436/29,939). One thousand six hundred and thirty-one deaths occurred within the ICU stay and 576 subsequent during hospital post-ICU discharge within 30-days; ICU and hospital case-fatality rates were 5.4% and 7.4%, respectively. An additional 229 patients died after hospital separation within 30 days of ICU admission of which 110 (48.0%) were transferred to another acute care hospital, 80 (34.9%) discharged home, and 39 (17.0%) transferred to an aged care/chronic care/rehabilitation facility. Patients who died after ICU discharge were older, had higher APACHE III scores, were more likely to be elective surgical patients, and were less likely to be out of state residents or managed in a tertiary referral hospital. Limiting determination of case-fatality to ICU information alone would correctly detect 95% (780/821) of all-cause mortality at day 3, 90% (1093/1213) at day 5, 75% (1524/2019) at day 15, 72% (1592/2244) at day 21, and 67% (1631/2436) at day 30 of follow-up.

CONCLUSIONS

Use of ICU case-fatality significantly underestimates the true burden and biases assessment of determinants of critical illness-related mortality in our region.

A review of the most impactful published pharmacotherapy-pertinent literature of 2019 and 2020 for clinicians caring for patients with thermal or inhalation injury

Keeping abreast with current literature can be challenging, especially for practitioners caring for patients sustaining thermal or inhalation injury. Practitioners caring for patients with thermal injuries publish in a wide variety of journals, which further increases the complexity for those with resource limitations. Pharmacotherapy research continues to be a minority focus in primary literature. This review is a renewal of previous years' work to facilitate extraction and review of the most recent pharmacotherapy-centric studies in patients with thermal and inhalation injury. Sixteen geographically dispersed, board-certified pharmacists participated in the review. A MeSH-based, filtered search returned 1,536 manuscripts over the previous 2-year period. After manual review and exclusions, only 98 (6.4%) manuscripts were determined to have a potential impact on current pharmacotherapy practices and included in the review. A summary of the 10 articles that scored highest are included in the review. Nearly half of the reviewed manuscripts were assessed to lack a significant impact on current practice. Despite an increase in published literature over the previous 2-year review, the focus and quality remain unchanged. There remains a need for investment in well-designed, high impact, pharmacotherapy-pertinent research for patients sustaining thermal or inhalation injuries.

A novel aqueous dimethyl trisulfide formulation is effective at low doses against cyanide toxicity in non-anesthetized mice and rats

BACKGROUND

Cyanide (CN) is a metabolic poison that is capable of intoxicating individuals through accidental or intentional means. With high concentration exposures, death can occur in minutes. In cases of mass casualty exposures, there is a need for a rapid-acting countermeasure capable of being administered in a short period of time in a pre-hospital setting to treat victims.

OBJECTIVE

These studies evaluate the safety and efficacy of a novel aqueous formulation of dimethyl trisulfide (DMTS) as an intramuscular (IM) CN countermeasure using non-anesthetized rodent models.

METHODS

Non-anesthetized rodents (mice and rats) were exposed to hydrogen cyanide (HCN) or potassium cyanide (KCN) along with immediate IM 10% DMTS treatment or vehicle treatment. Survival and other parameters, such as the time to recovery and assessment of clinical toxic signs (e.g., gasping, loss of righting reflex, convulsions, etc.), were quantified to determine the effectiveness of 10% DMTS treatment (12.5, 25, 75 mg/kg IM) compared to vehicle control treatment. A rat KCN delayed-treatment model with a 15-minute treatment delay was also utilized to simulate a real-life exposure/treatment scenario with 10% DMTS treatment. The stability of the 10% DMTS formulation was also assessed.

RESULTS

A 25 mg/kg IM dose of 10% DMTS exhibits potent efficacy against subcutaneous (SC) KCN challenge in both mice and rats and inhalational HCN exposure in mice. 10% DMTS treatment also shortens the time to recovery in rats using a delayed-treatment model.

CONCLUSION

IM treatment with 10% DMTS improves survival and clinical outcomes in non-anesthetized rodent models of acute CN toxicity. Additionally, the use of an SC KCN delayed-treatment model in rats is advised to assess the performance of a candidate CN countermeasure in a more realistic exposure/treatment scenario.

Advances in airway management and mechanical ventilation in inhalation injury

PURPOSE OF REVIEW

Airway management, mechanical ventilation, and treatment of systemic poisoning in burn patients with inhalation injury remains challenging. This review summarizes new concepts as well as open questions.

RECENT FINDINGS

Several life-threatening complications, such as airway patency impairment and respiratory insufficiency, can arise in burn patients and require adequate and timely airway management. However, unnecessary endotracheal intubation should be avoided. Direct visual inspection via nasolaryngoscopy can guide appropriate airway management decisions. In cases of lower airway injury, bronchoscopy is recommended to remove casts and estimate the extent of the injury in intubated patients. Several mechanical ventilation strategies have been studied. An interesting modality might be high-frequency percussive ventilation. However, to date, there is no sound evidence that patients with inhalation injury should be ventilated with modes other than those applied to non-burn patients. In all burn patients exposed to enclosed fire, carbon monoxide as well as cyanide poisoning should be suspected. Carbon monoxide poisoning should be treated with an inspiratory oxygen fraction of 100%, whereas cyanide poisoning should be treated with hydroxocobalamin.

SUMMARY

Burn patients need specialized care that requires specific knowledge about airway management, mechanical ventilation, and carbon monoxide and cyanide poisoning.

Outcomes after the administration of hydroxocobalamin

Background: Hydroxocobalamin is frequently administered to patients after injures sustained during structure fires or fires in enclosed spaces, prior to confirming inhalation injury with bronchoscopy. Hydroxocobalamin is generally considered safe. However, over the last several years, the safety of hydroxocobalamin has been called into question by case reports of crystalline nephropathy and interference with renal replacement therapies. Objectives: The aim of this project was to describe the population in which hydroxocobalamin was administered and assess clinical outcomes such as mortality and need for renal replacement therapy. We hypothesized that there is a relationship between the administration of hydroxocobalamin and the development of acute kidney injury (AKI). Methods: This was a retrospective chart review that was approved by our institution's research and regulatory compliance division as a performance improvement (PI) project (H-19-019nr). All patients admitted to the burn ICU at a large, government medical center between July 1, 2016 and April 30, 2019 were considered for inclusion. Patients were included if they received hydroxocobalamin after burn ICU admission. Patients who received hydroxocobalamin in the pre-ICU or pre-hospital setting were not included. Data were collected from the electronic medical record and included demographic information, number of hydroxocobalamin doses administered, burn size (%TBSA), presence and grade of inhalation injury, lactate levels during the first 72 hours of hospitalization, carboxyhemoglobin levels, duration of mechanical ventilation, and in-hospital mortality. Development of acute kidney injury (AKI) as per the AKIN criteria, as well as need for and duration of continuous renal replacement therapy (CRRT) were also collected. Results: Thirty five patients received at least 1 dose of hydroxocobalamin after ICU admission; 31 patients received 1 dose and 4 patients received 2 doses. Twenty nine (82.9%) patients who received hydroxocobalamin in the ICU were diagnosed with inhalation injury via bronchoscopy. The median fluid resuscitation requirement was 7.4 mL/kg/%TBSA (IQR 4.6, 12.7). Twenty two (63%) patients who received hydroxocobalamin developed an acute kidney injury (AKI) during the first 72 hours of admission, with the average time from burn to AKI being approximately 20 hours. Twenty one (60%) patients required CRRT at some point during their hospital stay, with 42.8% of patients being initiated on CRRT during the resuscitation period. On average, lactate clearance occurred in 34.6 hours; 11 (31.4%) patients did not clear lactate within 72 hours. One patient had a carboxyhemoglobin level greater than 10% on admission and 4 patients had a carboxyhemoglobin level greater than 3% on admission. The average time to carboxyhemoglobin level less than 3% was 3.4 ± 2.6 hours. The average duration of mechanical ventilation was 11 ± 7 days. Ten (28.9%) patients died during their hospital stay. Conclusions: Most patients who receive at least 1 dose of hydroxocobalamin after ICU admission developed AKI within the first 72 hours, with 42.8% of patients requiring CRRT during the initial resuscitation period. One-third of patients who received hydroxocobalamin after ICU admission died during their hospital stay. Further studies on the relationship between the administration of hydroxocobalamin and the development of AKI and in-hospital mortality are warranted.