Assessment of adverse events and predictors of neurological recovery after therapeutic hypothermia

Enteral plasma supports brain repair in newborn pigs after birth asphyxia

Newborns exposed to birth asphyxia transiently experience deficient blood flow and a lack of oxygen, potentially inducing hypoxic-ischaemic encephalopathy and subsequent neurological damage. Immunomodulatory components in plasma may dampen these responses. Using caesarean-delivered pigs as a model, we hypothesized that dietary plasma supplementation improves brain outcomes in pigs exposed to birth asphyxia. Mild birth asphyxia was induced by temporary occlusion of the umbilical cord prior to caesarean delivery. Motor development was assessed in asphyxiated (ASP) and control (CON) piglets using neonatal arousal, physical activity and gait test parameters before euthanasia on Day 4. The ASP pigs exhibited increased plasma lactate at birth, deficient motor skills and increased glial fibrillary acidic protein levels in CSF and astrogliosis in the putamen. The expression of genes related to oxidative stress, inflammation and synaptic functions was transiently altered in the motor cortex and caudate nucleus. The number of apoptotic cells among CTIP2-positive neurons in the motor cortex and striatal medium spiny neurons was increased, and maturation of preoligodendrocytes in the internal capsule was delayed. Plasma supplementation improved gait performance in the beam test, attenuated neuronal apoptosis and affected gene expression related to neuroinflammation, neurotransmission and antioxidants (motor cortex, caudate). We present a new clinically relevant animal model of moderate birth asphyxia inducing structural and functional brain damage. The components in plasma that support brain repair remain to be identified but may represent a therapeutic potential for infants and animals after birth asphyxia.

The hypokalaemia that came from the cold

While electrolyte disorders are common in nephrologists' clinical practice, hypothermia is a condition that nephrologists rarely encounter. Hypothermia can induce several pathophysiological effects on the human body, including hypokalaemia, which is reversible with rewarming. Despite growing evidence from animal research and human studies, the underlying mechanisms of hypothermia-induced hypokalaemia remain unclear. Boubes and colleagues recently presented a case series of hypokalaemia during hypothermia and rewarming, proposing a novel hypothesis for the underlying mechanisms. In this editorial, we review the current knowledge about hypothermia and associated electrolyte changes with insights into the effects of hypothermia on renal physiology.

Hypothermia as an Adjunctive Therapy to Percutaneous Intervention in ST-Elevation Myocardial Infarction: A Systematic Review and Meta-Analysis of Randomized Control Trials

INTRODUCTION

In the setting of acute ST-elevation myocardial infarction (STEMI), several randomized control trials (RCTs) suggested a potential benefit with the use of therapeutic hypothermia (TH). However, results from previous studies are contradictory.

METHOD

We performed a comprehensive literature search for studies that evaluated the efficacy and safety of adjunctive TH compared to the standard percutaneous coronary intervention (PCI) in awake patients with STEMI. The primary outcomes were the infarct size (IS) and microvascular obstruction (MVO) assessed by cardiac imaging at the end of follow-up. The secondary outcomes were major adverse cardiovascular events (MACE), procedure-related complications, and door-to-balloon time. Relative risk (RR) or the mean difference (MD) and corresponding 95 % confidence intervals (CIs) were calculated using the random-effects model.

RESULTS

A total of 10 RCTs, including 706 patients were included. As compared to standard PCI, TH was not associated with a statistically significant improvement in the IS (MD: -0.87 %, 95%CI: -2.97, 1.23; P = 0.42) or in the MVO (MD: 0.11 %, 95%CI: -0.06, 0.27; P = 0.21). MACE and its components were comparable between the two groups. However, the TH approach was associated with an increased risk of infection and prolonged door-to-balloon time. Furthermore, there was a trend in the TH group toward an increased incidence of stent thrombosis and paroxysmal atrial fibrillation.

CONCLUSIONS

According to our meta-analysis of published RCTs, TH is not beneficial in awake patients with STEMI and has a marginal safety profile with potential for care delays. Larger-scale RCTs are needed to further clarify our results.

Electrolyte considerations in targeted temperature management

PURPOSE

Targeted temperature management (TTM), including normothermia and therapeutic hypothermia, is used primarily for comatose patients with return of spontaneous circulation after cardiac arrest or following neurological injury. Despite the potential benefits of TTM, risks associated with physiological alterations, including electrolyte shifts, may require intervention.

SUMMARY

This review describes the normal physiological balance of electrolytes and temperature-related alterations as well as the impact of derangements on patient outcomes, providing general recommendations for repletion and monitoring of key electrolytes, including potassium, phosphate, and magnesium.

CONCLUSION

Frequent monitoring and consideration of patient variables such as renal function and other risk factors for adverse effects are important areas of awareness for clinicians caring for patients undergoing TTM.

Targeted temperature management at 36°C is a risk factor for ventilator-associated pneumonia

BACKGROUND

In contrast to the adult population, limited information is currently available on risk factors for ventilator-associated pneumonia (VAP) in children. Therapeutic hypothermia has been identified as a risk factor for the early onset of VAP in adults; however, the relationship between VAP and normothermia remains unclear. The present study investigated risk factors for VAP in children, with a focus on the deleterious effects of therapeutic normothermia on VAP.

METHODS

We retrospectively investigated the clinical characteristics of children treated with mechanical ventilation for more than 48 h and analyzed risk factors for VAP. The endpoint was the onset of VAP by the seventh day after the initiation of mechanical ventilation.

RESULTS

Among the 288 patients enrolled, seven (2.4%) developed VAP. No significant differences were observed in clinical backgrounds between the VAP and non-VAP groups. A univariate analysis identified target temperature management (TTM) at 36°C (p < 0.0001) and methylprednisolone (mPSL) pulse therapy (p = 0.02) as risk factors for VAP. An analysis of the time to the onset of VAP by the Kaplan-Meier plot and log-rank test revealed a significantly higher incidence of VAP in the TTM group (p < 0.0001) and mPSL pulse group (p = 0.001).

CONCLUSION

TTM at 36°C and mPSL pulse therapy may be risk factors for VAP in the pediatric population.

Association of multiple rib fractures with the frequency of pneumonia in the post-resuscitation period

Purpose

Successful cardiopulmonary resuscitation is associated with a high incidence of chest wall injuries. However, few studies have examined chest wall injury as a risk factor for respiratory complications after cardiopulmonary resuscitation. Therefore, herein, we investigated the association of multiple rib fractures on the incidence of post-resuscitation pneumonia.

Methods

This single-centre retrospective cohort study enrolled adult, nontraumatic, out-of-hospital cardiac arrest patients who maintained circulation for more than 48 h between June 2015 and May 2019. Rib fractures were evaluated by computed tomography on the day of hospital admission. The association with newly developed pneumonia within 7 days of hospitalisation was analysed using a Fine-Gray proportional hazards regression model adjusted for the propensity score of multiple rib fractures estimated from age, sex, presence of witnessed status, bystander CPR, initial rhythm, and total CPR time and for previously reported risk factors for pneumonia (therapeutic hypothermia and prophylactic antibiotics).

Results

Overall, 683 patients with out-of-hospital cardiac arrest were treated; 87 eligible cases were enrolled for analysis. Thirty-two (36.8%) patients had multiple rib fractures identified on computed tomography, and 35 (40.2%) patients developed pneumonia. The presence of multiple rib fractures was significantly associated with a higher incidence of pneumonia, consistently both with and without adjustment for background factors (unadjusted hazard ratio 4.63, 95% confidence interval: 2.35–9.13, p < 0.001; adjusted hazard ratio 4.03, 95% confidence interval: 2.08–7.82, p < 0.001).

Conclusions

Multiple rib fractures are independently associated with the development of pneumonia after successful resuscitation.

Delirium in ICU Patients after Cardiac Arrest: A Scoping Review

Introduction: The incidence of delirium in the intensive care unit is high, although it may differ according to the specific characteristics of the unit. Despite the rapid development of research on delirium in recent years, the pathophysiological mechanisms leading to the clinical presentation of delirium are still subject to hypotheses. The aim of this review was to describe the incidence of delirium in cardiac arrest survivors and the clinical impact of delirium on patient outcomes. Methods: A scoping review was conducted in the second quarter of 2022. The number of articles retrieved during each search test was limited to studies conducted between 2010 and 2020. Strict inclusion and exclusion criteria were applied. The last search was conducted in May 2022. Results: A total of 537 records was initially obtained from the databases. After discarding duplicates, selecting titles and abstracts, and then analyzing full-text articles, 7 studies met the inclusion criteria. The incidence of delirium in the cardiac arrest survivor population ranged from 8% to as high as 100%. The length of stay in ICU and hospital was significantly longer in patients with delirium than those without. Ninety-eight percent of patients had cognitive or perceptual impairment and psychomotor impairment. Of the seven studies included in the analysis, the RASS, CAM, and NuDesc scales were used to diagnose delirium. Potential risk factors that may influence the duration of delirium include age and time since resuscitation; propofol use shortened the duration of delirium. Conclusion: the incidence of delirium in ICU patients who survived CA is high. Cardiac arrest is an additional predisposing factor for delirium. In cardiac arrest survivors, the occurrence of delirium prolongs the duration of ICU and hospital stay and adversely affects functional outcomes. The most common type of delirium among this population was hypoactive delirium. A large percentage of patients manifested symptoms such as cognitive or perception impairment, psychomotor impairment, and impaired concentration and attention.

Selective Brain Cooling: A New Horizon of Neuroprotection

Therapeutic hypothermia (TH), which prevents irreversible neuronal necrosis and ischemic brain damage, has been proven effective for preventing ischemia-reperfusion injury in post-cardiac arrest syndrome and neonatal encephalopathy in both animal studies and clinical trials. However, lowering the whole-body temperature below 34°C can lead to severe systemic complications such as cardiac, hematologic, immunologic, and metabolic side effects. Although the brain accounts for only 2% of the total body weight, it consumes 20% of the body's total energy at rest and requires a continuous supply of glucose and oxygen to maintain function and structural integrity. As such, theoretically, temperature-controlled selective brain cooling (SBC) may be more beneficial for brain ischemia than systemic pan-ischemia. Various SBC methods have been introduced to selectively cool the brain while minimizing systemic TH-related complications. However, technical setbacks of conventional SBCs, such as insufficient cooling power and relatively expensive coolant and/or irritating effects on skin or mucosal interfaces, limit its application to various clinical settings. This review aimed to integrate current literature on SBC modalities with promising therapeutic potential. Further, future directions were discussed by exploring studies on interesting coping skills in response to environmental or stress-induced hyperthermia among wild animals, including mammals and birds.

In the ICU - delirium post cardiac arrest

PURPOSE OF REVIEW

The present review aims to describe the clinical impact and assessment tools capable of identifying delirium in cardiac arrest survivors and providing strategies aimed at preventing and treating delirium.

RECENT FINDINGS

Patient factors leading to a cardiac arrest, initial resuscitation efforts, and postresuscitation management all influence the potential for recovery and the risk for development of delirium. Data suggest that delirium in cardiac arrest survivors is an independent risk factor for morbidity and mortality. Recognizing delirium in postcardiac arrest patients can be challenging; however, detection is not only achievable, but important as it may aid in predicting adverse outcomes. Serial neurologic examinations and delirium assessments, targeting light sedation when possible, limiting psychoactive medications, and initiating patient care bundles are important care aspects for not only allowing early identification of primary and secondary brain injury, but in improving patient morbidity and mortality.

SUMMARY

Developing delirium after cardiac arrest is associated with increased morbidity and mortality. The importance of addressing modifiable risk factors, recognizing symptoms early, and initiating coordinated treatment strategies can help to improve outcomes within this high risk population.

Cannabinoid Receptor Agonist WIN55, 212-2 Adjusts Lipid Metabolism in a Rat Model of Cardiac Arrest

The objective of this study was to investigate the effects of pharmacologically induced hypothermia with WIN55, 212-2 (WIN)on postresuscitation myocardial function, microcirculation, and metabolism-specific lipids in a rat cardiac arrest (CA) model. Ventricular fibrillation was electrically induced and untreated for 6 minutes in 24 Sprague-Dawley rats weighing 450-550 g. Cardiopulmonary resuscitation including chest compression and mechanical ventilation was then initiated and continued for 8 minutes, followed by defibrillation. At 5 minutes after restoration of spontaneous circulation (ROSC), animals were randomized into four groups: (1) normothermia with vehicle (NT); (2) physical hypothermia with vehicle (PH); (3) WIN55, 212-2 with normothermia (WN); and (4) WIN55, 212-2 with hypothermia (WH). For groups of WN and WH, WIN was administered by continuous intravenous infusion with a syringe pump for 4 hours. PH started at 5 minutes after resuscitation. NT maintained core temperature at 37°C ± 0.2°C with the aid of a heating blanket. Hypothermia groups maintained temperature at 33°C ± 0.5°C for 4 hours after ROSC. There was a significant improvement in myocardial function as measured by ejection fraction, cardiac output, and myocardial performance index in animals treated with WH and PH beginning at 1 hour after start of infusion. In the WH and PH groups, buccal microcirculation was significantly improved compared with NT and WN. Plasma at pre-CA and ROSC 4 hours was harvested for lipid metabolism. The WH group appeared to be closer to baseline than the other groups in lipid metabolism. lysophosphatidylcholine (LPC) 18:2, free fatty acid (FFA) 22:6, and ceramide (CER) (24:0) changed significantly among the lipidomic data compared with NT (p < 0.05). Postresuscitation hypothermia improved myocardial function and microcirculation. WH-mediated lipid metabolism had the best metabolic outcome to bring back the animals to normal metabolism, which may be protective to improve outcomes of CA. LPC 18:2, FFA 22:6, and CER (24:0) may be important predictors of outcomes of CA.

End stage renal disease modifies the effect of targeted temperature management after out-of-hospital cardiac arrest

INTRODUCTION

Kidney function can affect the permeability of the blood-brain barrier; thus, end-stage renal disease (ESRD) may alter the effects of targeted temperature management (TTM) on the neurological outcomes of out-of-hospital cardiac arrest (OHCA) patients. We aimed to investigate whether the interaction effect of TTM on outcomes after OHCA was observed among patients with and without ESRD.

METHODS

Adult OHCA patients with presumed cardiac etiology who attained sustained return of spontaneous circulation from 2013 to 2017 were included using nationwide OHCA registry. The main exposure variable was TTM. The primary endpoint was survival with good neurological recovery. Multivariable logistic regression analysis was performed after adjustment for potential confounders. To compare the effect of ESRD on TTM, an interaction term (TTM × ESRD) was added to the model.

RESULTS

A total of 21,250 patients were included in the analysis; 2693 (12.7%) patients underwent TTM. ESRD was observed in 128 (4.8%) in the TTM group and 767 (4.1%) in the no-TTM group. The TTM group showed better outcomes than the no-TTM group (32.4% vs. 17.2%, p < 0.01). The adjusted odds ratio of TTM for good neurological recovery in the entire study group was 1.15 (95% CI, 1.03-1.29). In the interaction model, the adjusted odds ratio of TTM for good neurological recovery was 0.47 (95% CI, 0.23-0.98) in the ESRD group vs. 1.54 (95% CI, 1.00-2.39) in the no-ESRD group.

CONCLUSIONS

The interaction effect between ESRD and TTM on neurologic outcome was positive in adult OHCA initial survivors with presumed cardiac etiology.

Effects of dexmedetomidine vs sufentanil during percutaneous tracheostomy for traumatic brain injury patients: A prospective randomized controlled trial

BACKGROUND

Percutaneous tracheostomy, almost associated with cough reflex and hemodynamic fluctuations, is a common procedure for traumatic brain injury (TBI) patients, especially those in neurosurgery intensive care units (NICUs). However, there are currently a lack of effective preventive measures to reduce the risk of secondary brain injury. The aim of this study was to compare the effect of dexmedetomidine (DEX) vs sufentanil during percutaneous tracheostomy in TBI patients.

METHODS

The 196 TBI patients who underwent percutaneous tracheostomy were randomized divided into 3 groups: group D1 (n = 62, DEX infusion at 0.5 μg·kg for 10 minutes, then adjusted to 0.2-0.7 μg·kg·hour), group D2 (n = 68, DEX infusion at 1 μg·kg for 10 minutes, then adjusted to 0.2-0.7 μg·kg·hour), and group S (n = 66, sufentanil infusion 0.3 μg·kg for 10 minutes, then adjusted to 0.2-0.4 μg·kg·hour). The bispectral index (BIS) of all patients was maintained at 50 to 70 during surgery. Anesthesia onset time, hemodynamic variables, total cumulative dose of DEX/sufentanil, total doses of rescue propofol and fentanyl, time to first dose of rescue propofol and fentanyl, number of intraoperative patient movements and cough reflexes, adverse events, and surgeon satisfaction score were recorded.

RESULTS

Anesthesia onset time was significantly lower in group D2 than in both other groups (14.35 ± 3.23 vs 12.42 ± 2.12 vs 13.88 ± 3.51 minutes in groups D1, D2, and S, respectively; P < .001). Both heart rate and mean arterial pressure during percutaneous tracheostomy were more stable in group D2. Total doses of rescue propofol and fentanyl were significantly lower in group D2 than in group D1 (P < .001). The time to first dose of rescue propofol and fentanyl were significantly longer in group D2 than in both other groups (P < .001). The number of patient movements and cough reflexes during percutaneous tracheostomy were lower in group D2 than in both other groups (P < .001). The overall incidences of tachycardia and hypertension (which required higher doses of esmolol and urapidil, respectively) were also lower in group D2 than in both other groups (P < .05). Three patients in group S had respiratory depression compared to X in the D1 group and X in the D2 group. The surgeon satisfaction score was significantly higher in group D2 than in both other groups (P < .05).

CONCLUSIONS

During percutaneous tracheostomy, compared with sufentanil, DEX (1 μg·kg for 10 minutes, then adjusted to 0.2-0.7 μg·kg·hour) can provide the desired attenuation of the hemodynamic response without increased adverse events. Consequently, DEX could be used safely and effectively during percutaneous tracheostomy in TBI patients.

Hypothermic treatment after computer-controlled compression in minipig: A preliminary report on the effect of epidural vs. direct spinal cord cooling

The aim of the present study was to investigate the therapeutic efficacy of local hypothermia (beginning 30 min post-injury persisting for 5 h) on tissue preservation along the rostro-caudal axis of the spinal cord (3 cm cranially and caudally from the lesion site), and the prevention of injury-induced functional loss in a newly developed computer-controlled compression model in minipig (force of impact 18N at L3 level), which mimics severe spinal cord injury (SCI). Minipigs underwent SCI with two post-injury modifications (durotomy vs. intact dura mater) followed by hypothermia through a perfusion chamber with cold (epidural t≈15°C) saline, DMEM/F12 or enriched DMEM/F12 (SCI/durotomy group) and with room temperature (t≈24°C) saline (SCI-only group). Minipigs treated with post-SCI durotomy demonstrated slower development of spontaneous neurological improvement at the early postinjury time points, although the outcome at 9 weeks of survival did not differ significantly between the two SCI groups. Hypothermia with saline (t≈15°C) applied after SCI-durotomy improved white matter integrity in the dorsal and lateral columns in almost all rostro-caudal segments, whereas treatment with medium/enriched medium affected white matter integrity only in the rostral segments. Furthermore, regeneration of neurofilaments in the spinal cord after SCI-durotomy and hypothermic treatments indicated an important role of local saline hypothermia in the functional outcome. Although saline hypothermia (24°C) in the SCI-only group exhibited a profound histological outcome (regarding the gray and white matter integrity and the number of motoneurons) and neurofilament protection in general, none of the tested treatments resulted in significant improvement of neurological status. The findings suggest that clinically-proven medical treatments for SCI combined with early 5 h-long saline hypothermia treatment without opening the dural sac could be more beneficial for tissue preservation and neurological outcome compared with hypothermia applied after durotomy.

Independent Risk Factors for the Shivering Occurrence During Induction Period in Out-of-Hospital Cardiac Arrest Survivors Treated with Targeted Temperature Management

The occurrence of shivering during the induction period of targeted temperature management (TTM) remains a therapeutic obstacle, which delays the achievement of target temperature. The aim of this study was to identify risk factors leading to shivering during the induction period. We analyzed a prospective cohort of adult out-of-hospital cardiac arrest (OHCA) survivors treated with TTM from January 2015 to June 2017. Patients who developed shivering during the induction period were compared to those who did not. Multivariable analysis was performed to determine risk factors of shivering. Among 80 patients treated with TTM, shivering occurred in 22 patients (27.5%). In the shivering group, the time to achieve target temperature was significantly delayed (245 minutes vs. 151 minutes, p = 0.005). Multivariable analysis showed that being underweight (OR, 18.40; 95% CI, 1.89-179.19) or overweight (OR, 8.65; 95% CI, 1.60-46.80), age <65 years (OR, 5.54; 95% CI, 1.25-16.12), and duration of cardiac arrest <20 minutes (OR, 4.50; 95% CI, 1.25-16.12) were predictors for the occurrence of shivering. OHCA patients with abnormal body weight, age <65 years, and duration of cardiac arrest <20 minutes should be monitored thoroughly for early recognition of shivering.

A Combination of Three Repurposed Drugs Administered at Reperfusion as a Promising Therapy for Postischemic Brain Injury

Cerebral ischemia leads to multifaceted injury to the brain. A polytherapeutic drug that can be administered immediately after reperfusion may increase protection to the brain by simultaneously targeting multiple deleterious cascades. This study evaluated efficacy of the combination of three clinically approved drugs: lamotrigine, minocycline, and lovastatin, using two mouse models: global and focal cerebral ischemia induced by transient occlusion of the common carotid arteries or the middle cerebral artery, respectively. In vitro, the combination drug, but not single drug, protected neurons against oxygen-glucose deprivation (OGD)-induced cell death. The combination drug simultaneously targeted cell apoptosis and DNA damage induced by ischemia. Besides acting on neurons, the combination drug suppressed inflammatory processes in microglia and brain endothelial cells induced by ischemia. In a transient global ischemia model, the combination drug, but not single drug, suppressed microglial activation and inflammatory cytokine production, and reduced neuronal damage. In a transient focal ischemia model, the combination drug, but not single drug, attenuated brain infarction, suppressed infiltration of peripheral neutrophils, and reduced neurological deficits following ischemic stroke. In summary, the combination drug confers a broad-spectrum protection against ischemia/reperfusion (I/R) injury and could be a promising approach for early neuroprotection after out-of-hospital cardiac arrest or ischemic stroke.

Incidence and prognosis of nosocomial infection after recovering of cardiac arrest in children

OBJECTIVE

to analyze the incidence of infection in children who have suffered an in-hospital cardiac arrest (CA) and the association with mortality.

METHODS

A retrospective unicenter observational study on a prospective database with children between one month and 16 years old, who have suffered an in-hospital CA was performed. Clinical, analytical and monitorization data, treatment, mortality and cause of death were recorded.

RESULTS

57 children were studied (57.6% males). Recovery of spontaneous circulation (ROSC) was achieved in 50 children (87.7%) and 32 (59.3%) survived. After ROSC, 28 patients (56% of those who achieved ROSC) were diagnosed of infection. There were not significant differences in mortality between patients infected (42.9%) and uninfected (27.3%) p=0.374. Only one died in consequence of a sepsis with multiorganic failure.

CONCLUSIONS

The frequency of infection in children after recovering of a cardiac arrest is high. There were no statistically significant differences in mortality between patients with and without infection after ROSC.

The role of therapeutic hypothermia in the management of acute spinal cord injury

This review paper investigates the history, efficacy, and administration of systemic and local hypothermia for spinal cord injury (SCI). It summarizes the published experimental and clinical evidence on hypothermia for SCI and analyzes the potential for further research. Early experimental animal research showed that local hypothermia improved recovery and gain of function after acute SCI. However, in the early 1970s, clinical research findings did not coincide with results of these animal trials, which led to a loss of interest in local hypothermia. Since the 1980s, systemic hypothermia has been successfully used to treat SCI in both animals and humans. An abundance of positive evidence suggests that clinical trials are needed to determine the effectiveness of hypothermia for SCI. As a first step, we investigated the published clinical and experimental evidence on the use of hypothermia for SCI patients, who have few available treatment options. We searched PubMed for English-language reports published from 1940 to 2016 containing terms related to SCI treatment using hypothermia. We reviewed all articles on local hypothermia and acute SCI or on systemic hypothermia and acute SCI. Bibliographies of retrieved publications were also screened for additional citations. Ninety-six papers were selected. The clinical use of hypothermia is most successful if applied according to certain optimized parameters (e.g., duration, temperature, time from injury to initiation of cooling, and rewarming time). Preliminary data suggest that modest systemic hypothermia applied for 48h provides the best therapeutic value, but the parameters for use of local hypothermia vary greatly. Experimental evidence and some clinical evidence suggest that both local hypothermia and systemic hypothermia are beneficial for acute SCI. Future research should focus on defining the optimal levels of parameters. Large, multicenter, controlled clinical trials are needed to investigate its therapeutic potential.

Adverse drug reactions in therapeutic hypothermia after cardiac arrest

BACKGROUND

Therapeutic hypothermia (TH) improves survival and neurologic function in comatose survivors of cardiac arrest. Many medications used to support TH have altered pharmacokinetics and pharmacodynamics during this treatment. It is unknown if or at what frequency the medications used during TH cause adverse drug reactions (ADRs).

METHODS

A retrospective chart review was conducted for patients admitted to an intensive care unit (ICU) after cardiac arrest and treated with TH from January 2009 to June 2012 at two urban, university-affiliated, tertiary-care medical centres. Medications commonly used during TH were screened for association with significant ADRs (grade 3 or greater per Common Terminology Criteria for Adverse Events) using three published ADR detection instruments.

RESULTS

A total of 229 patients were included, the majority being males with median age of 62 presenting with an out-of-hospital cardiac arrest in pulseless electrical activity or asystole. The most common comorbidities were hypertension, coronary artery disease, and diabetes mellitus. There were 670 possible ADRs and 69 probable ADRs identified. Of the 670 possible ADRs, propofol, fentanyl, and acetaminophen were the most common drugs associated with ADRs. Whereas fentanyl, insulin, and propofol were the most common drugs associated with a probable ADR. Patients were managed with TH for a median of 22 hours, with 38% of patients surviving to hospital discharge.

CONCLUSIONS

Patients undergoing TH after cardiac arrest frequently experience possible adverse reactions associated with medications and the corresponding laboratory abnormalities are significant. There is a need for judicious use and close monitoring of drugs in the setting of TH until recommendations for dose adjustments are available to help prevent ADRs.

Mild therapeutic hypothermia in patients resuscitated from out-of-hospital cardiac arrest: A meta-analysis of randomized controlled trials

AIMS

Guidelines recommend mild therapeutic hypothermia (MTH) for survivors of out-of-hospital cardiac arrest (OHCA). However, there is little literature demonstrating a survival benefit. We performed a meta-analysis of randomized controlled trials (RCTs) assessing the efficacy of MTH in patients successfully resuscitated from OHCA.

MATERIALS AND METHODS

Electronic databases were searched for RCT involving MTH in survivors of OHCA, and the results were put through a meta-analysis. The primary endpoint was all-cause mortality, and the secondary endpoint was favorable neurological function. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed using the Mantel-Haenszel method. A fixed-effect model was used and, if heterogeneity (I2 ) was >40, effects were analyzed using a random model.

RESULTS

Six RCT (n = 1400 patients) were included. Overall survival was 50.7%, and favorable neurological recovery was 45.5%. Pooled data demonstrated no significant all-cause mortality (OR, 0.81; 95% CI 0.55-1.21) or neurological recovery (OR, 0.77; 95% CI 0.47-1.24). No evidence of publication bias was observed.

CONCLUSION

This meta-analysis demonstrated that MTH did not confer benefit on overall survival rate and neurological recovery in patients resuscitated from OHCA.

Analgesia, sedation, and neuromuscular blockade during targeted temperature management after cardiac arrest

The approach to sedation, analgesia, and neuromuscular blockade during targeted temperature management (TTM) remains largely unstudied, forcing clinicians to adapt previous research from other patient environments. During TTM, very little data guide drug selection, doses, and specific therapeutic goals. Sedation should be deep enough to prevent awareness during neuromuscular blockade, but titration is complex as metabolism and clearance are delayed for almost all drugs during hypothermia. Deeper sedation is associated with prolonged intensive care unit (ICU) and ventilator therapy, increased delirium and infection, and delayed wakening which can confound early critical neurological assessments, potentially resulting in erroneous prognostication and inappropriate withdrawal of life support. We review the potential therapeutic goals for sedation, analgesia, and neuromuscular blockade during TTM; the adverse events associated with that treatment; data suggesting that TTM and organ dysfunction impair drug metabolism; and controversies and potential benefits of specific monitoring. We also highlight the areas needing better research to guide our therapy.

Therapeutic hypothermia in ST elevation myocardial infarction: a systematic review and meta-analysis of randomised control trials

OBJECTIVE

Our objective is to gain a better understanding of the efficacy and safety of therapeutic hypothermia (TH) in patients with acute ST elevation myocardial infarction (STEMI) through an analysis of randomised controlled trials (RCTs).

BACKGROUND

Several RCTs have suggested a positive outcome with the use of TH in the prevention of myocardial injury in the setting of an acute STEMI. However, there are currently no clinical trials that have conclusively shown any significant benefit.

METHODS

Electronic databases were used to identify RCTs of TH in the patient population with STEMI. The primary efficacy end point was major adverse cardiovascular event (MACE). Secondary efficacy end points included all-cause mortality, infarct size, new myocardial infarction and heart failure/pulmonary oedema (HF/PO). All-bleeding, ventricular arrhythmias and bradycardias were recorded as the safety end points.

RESULTS

Six RCTs were included in this meta-analysis, enrolling a total of 819 patients. There was no significant benefit from TH in preventing MACE (OR, 01.04; 95% CI 0.37 to 2.89), all-cause mortality (OR, 1.48; 95% CI 0.68 to 3.19), new myocardial infarction (OR, 0.99; 95% CI 0.20 to 4.94), HF/PO (OR, 0.52; 95% CI 0.15 to 1.77) or infarct size (standard difference of the mean (SDM), -0.1; 95% CI -0.23 to 0.04). However, a significant reduction of infarct size was observed with TH utilisation in anterior wall myocardial infarction (SDM, -0.23; 95% CI -0.45 to -0.02). There was no significant difference seen for the safety end points all-bleeding (OR 1.32; 95% CI 0.77 to 2.24), ventricular arrhythmias (OR, 0.85; 95% CI 0.54 to 1.36) or bradycardias (OR, 1.16; 95% CI 0.74 to 1.83).

CONCLUSIONS

Although TH appears to be safe in patients with STEMI, meta-analysis of published RCTs indicates that benefit is limited to reduction of infarct size in patients with anterior wall involvement with no demonstrable effect on all-cause mortality, recurrent myocardial infarction or HF/PO.

Early pneumonia and timing of antibiotic therapy in patients after nontraumatic out-of-hospital cardiac arrest

Background

While early pneumonia is common in patients after out-of-hospital cardiac arrest (OHCA), little is known about the impact of pneumonia and the optimal timing of antibiotic therapy after OHCA.

Methods

We conducted a 5-year retrospective cohort study, including patients who suffered from OHCA and were treated with therapeutic hypothermia. ICU treatment was strictly standardized with defined treatment goals and procedures. Medical records, chest radiographic images and microbiological findings were reviewed.

Results

Within the study period, 442 patients were admitted to our medical ICU after successfully resuscitated cardiac arrest. Of those, 174 patients fulfilled all inclusion and no exclusion criteria and were included into final analysis. Pneumonia within the first week could be confirmed in 39 patients (22.4 %) and was confirmed or probable in 100 patients (57.5 %), without a difference between survivors and non-survivors (37.8 % vs. 23.1 % confirmed pneumonia, p = 0.125). In patients with confirmed pneumonia a tracheotomy was performed more frequently (28.2 vs. 12.6 %, p = 0.026) compared to patients without confirmed pneumonia. Importantly, patients with confirmed pneumonia had a longer ICU- (14.0 [8.5-20.0] vs. 8.0 [5.0-14.0] days, p < 0.001) and hospital stay (23.0 [11.5-29.0] vs. 15.0 [6.5-25.0] days, p = 0.016).

A positive end expiratory pressure (PEEP) > =10.5 mbar on day 1 of the hospital stay was identified as early predictor of confirmed pneumonia (odds ratio 2.898, p = 0.006). No other reliable predictor could be identified.

Median time to antibiotic therapy was 8.7 [5.4-22.8] hours, without a difference between patients with or without confirmed pneumonia (p = 0.381) and without a difference between survivors and non-survivors (p = 0.264). Patients receiving antibiotics within 12 hours after admission had a shorter ICU- (8.0 [4.0-14.0] vs. 10.5 [6.0-16.0] vs. 13.5 [8.0-20.0] days, p = 0.004) and hospital-stay (14.0 [6.0-25.0] vs. 16.5 [11.0-27.0] vs. 21.0 [17.0-28.0] days, p = 0.007) compared to patients receiving antibiotics after 12 to 36 or more than 36 hours, respectively.

Conclusions

Early pneumonia may extend length of ICU- and hospital-stay after OHCA and its occurrence is difficult to predict. A delayed initiation of antibiotic therapy in OHCA patients may increase the duration of the ICU- and hospital-stay.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1191-y) contains supplementary material, which is available to authorized users.

Adverse events associated with poor neurological outcome during targeted temperature management and advanced critical care after out-of-hospital cardiac arrest

Introduction

The aim of this study was to investigate the association of adverse events (AEs) during targeted temperature management (TTM) and other AEs and concomitant treatments during the advanced critical care period with poor neurological outcome at hospital discharge in adult out-of-hospital cardiac arrest (OHCA) patients.

Methods

This was a retrospective study using Korean Hypothermia Network registry data of adult OHCA patients treated with TTM in 24 teaching hospitals throughout South Korea from 2007 to 2012. Demographic characteristics, resuscitation and post-resuscitation variables, AEs, and concomitant treatments during TTM and the advanced critical care were collected. The primary outcome was poor neurological outcome, defined as a cerebral performance category (CPC) score of 3–5 at hospital discharge. The AEs and concomitant treatments were individually entered into the best multivariable predictive model of poor neurological outcome to evaluate the associations between each variable and outcome.

Results

A total of 930 patients, including 704 for whom a complete dataset of AEs and covariates was available for multivariable modeling, were included in the analysis; 476 of these patients exhibited poor neurological outcome [CPC 3 = 50 (7.1 %), CPC 4 = 214 (30.4 %), and CPC 5 = 212 (30.1 %)]. Common AEs included hyperglycemia (45.6 %), hypokalemia (31.3 %), arrhythmia (21.3 %) and hypotension (29 %) during cooling, and hypotension (21.6 %) during rewarming. Bleeding (5 %) during TTM was a rare AE. Common AEs during the advanced critical care included pneumonia (39.6 %), myoclonus (21.9 %), seizures (21.7 %) and hypoglycemia within 72 hours (23 %). After adjusting for independent predictors of outcome, cooling- and rewarming-related AEs were not significantly associated with poor neurological outcome. However, sepsis, myoclonus, seizure, hypoglycemia within 72 hours and anticonvulsant use during the advanced critical care were associated with poor neurological outcome [adjusted odds ratios (95 % confidence intervals) of 3.12 (1.40–6.97), 3.72 (1.93–7.16), 4.02 (2.04–7.91), 2.03 (1.09–3.78), and 1.69 (1.03–2.77), respectively]. Alternatively, neuromuscular blocker use was inversely associated with poor neurological outcome (0.48 [0.28–0.84]).

Conclusions

Cooling- and rewarming-related AEs were not associated with poor neurological outcome at hospital discharge. Sepsis, myoclonus, seizure, hypoglycemia within 72 hours and anticonvulsant use during the advanced critical care period were associated with poor neurological outcome at hospital discharge in our study.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0991-9) contains supplementary material, which is available to authorized users.

Prophylactic antibiotics are associated with a lower incidence of pneumonia in cardiac arrest survivors treated with targeted temperature management

INTRODUCTION

Prophylactic antibiotics (PRO) reduce the incidence of early-onset pneumonia in comatose patients with structural brain injury, but have not been examined in cardiac arrest survivors undergoing targeted temperature management (TTM). We investigated the effect of PRO on the development of pneumonia in that population.

METHODS

We conducted a retrospective cohort study comparing patients treated with PRO to those not receiving PRO (no-PRO) using Northern Hypothermia Network registry data. Cardiac arrest survivors ≥ 18 years of age with a GCS<8 at hospital admission and treated with TTM at 32-34 °C were enrolled in the registry. Differences were analyzed in univariate analyses and with logistic regression models to evaluate independent associations of clinical factors with incidence of pneumonia and good functional outcome.

RESULTS

416 of 1240 patients (33.5%) received PRO. Groups were similar in age, gender, arrest location, initial rhythm, and time from collapse to return of spontaneous circulation. PRO patients had less pneumonia (12.6% vs. 54.9%, p < 0.001) and less sepsis (1.2 vs. 5.7%, p < 0.001) compared to no-PRO patients. ICU length of stay (98 vs. 100 h, p = 0.2) and incidence of a good functional outcome (41.1 vs. 36.6%, p = 0.19) were similar between groups. Backwards stepwise logistic regression demonstrated PRO were independently associated with a lower incidence of pneumonia (OR 0.09, 95% 0.06-0.14, p < 0.001) and a similar incidence of good functional outcome.

CONCLUSIONS

Prophylactic antibiotics were associated with a reduced incidence of pneumonia but a similar rate of good functional outcome.