Variation in Sedation and Neuromuscular Blockade Regimens on Outcome After Cardiac Arrest

Impact of sedation depth on neurological outcome in post-cardiac arrest patients - A retrospective cohort study

AIMS

Whether targeted temperature management (TTM) might improve neurologic prognosis in patients after cardiac arrest is currently under debate. Data concerning sedation depth during TTM is rare. This study aimed to compare the impact of different sedation depths on neurological outcomes in post-cardiac arrest patients undergoing TTM.

METHODS

In this retrospective, before-and-after registry study, all patients receiving TTM on a medical ICU between 08/2016 and 03/2021 were included. This study evaluated the following sedation targets: RASS-target during TTM -5 until 08/2019 and RASS-target -4 since 09/2019. The primary endpoint was favorable neurological outcome at ICU discharge, defined as a Cerebral Performance Category (CPC) score of 1 or 2.

RESULTS

403 patients were included (RASS-target -5: N = 285; RASS-target -4: N = 118). Favorable neurological outcome was documented in 54/118 (45.8 %) patients in the group with a RASS-target of -4 compared to 111/285 (38.9 %) in the group with a RASS-target of -5. After adjustment for age, sex, initial shockable rhythm, bystander CPR, duration of CPR and mean arterial pressure 12 h after CPR, favorable neurological outcome was associated with RASS-target -4 (OR 1.82 (95 % CI: 1.02-3.23); p = 0.042). ICU survival was similar in both groups while 30-day survival was associated with RASS-target -4 (OR 1.81 (1.01-3.26); p = 0.047).

CONCLUSION

Lighter sedation strategies during TTM after cardiac arrest might improve outcome and should be further investigated.

Management of Patients With Cardiac Arrest Requiring Interfacility Transport: A Scientific Statement From the American Heart Association

People who experience out-of-hospital cardiac arrest often require care at a regional center for continued treatment after resuscitation, but many do not initially present to the hospital where they will be admitted. For patients who require interfacility transport after cardiac arrest, the decision to transfer between centers is complex and often based on individual clinical characteristics, resources at the presenting hospital, and available transport resources. Once the decision has been made to transfer a patient after cardiac arrest, there is little direct guidance on how best to provide interfacility transport. Accepting centers depend on transferring emergency departments and emergency medical services professionals to make important and nuanced decisions about postresuscitation care that may determine the efficacy of future treatments. The consequences of early care are greater when transport delays occur, which is common in rural areas or due to inclement weather. Challenges of providing interfacility transfer services for patients who have experienced cardiac arrest include varying expertise of clinicians, differing resources available to them, and nonstandardized communication between transferring and receiving centers. Although many aspects of care are insufficiently studied to determine implications for specific out-of-hospital treatment on outcomes, a general approach of maintaining otherwise recommended postresuscitation care during interfacility transfer is reasonable. This includes close attention to airway, vascular access, ventilator management, sedation, cardiopulmonary monitoring, antiarrhythmic treatments, blood pressure control, temperature control, and metabolic management. Patient stability for transfer, equity and inclusion, and communication also must be considered. Many of these aspects can be delivered by protocol-driven care.

Variability in temperature control practices amongst the Influence of Cooling duration on Efficacy in Cardiac Arrest Patients (ICECAP) trial

AIM

Temperature control is a complex bundled intervention; the synergistic impact of each individual component is ill defined and underreported. Resultantly, the influence of parameter optimization on temperature control's overall neuroprotective effect remains poorly understood. To characterize variability in temperature control parameters and barriers to short pre-induction and induction times, we surveyed sites enrolling in an ongoing multicenter clinical trial.

METHODS

This was a cross-sectional, survey study evaluating temperature control practices within the Influence of Cooling duration on Efficacy in Cardiac Arrest Patients (ICECAP) trial (NCT04217551). A 23-question web-based survey (Qualtrics) was distributed to the site principal investigators by email. Respondents were asked about site practices pertaining to the use of temperature control, including the request to upload individual institutional protocols. Open-ended responses were analyzed qualitatively by categorizing responses into identified themes. To complement survey level data, records pertaining to the quality of temperature control were extracted from the ICECAP trial database.

RESULTS

The survey response rate was 75% (n = 51) including 23.5% (n = 12) survey respondents who uploaded institutional protocols. Most sites reported having institutional protocols for temperature control (n = 41; 80%), including 62.5% (n = 32) who had separate protocols for initiation of temperature control in the emergency department (ED). Fewer sites had protocols specific to sedation or neuromuscular blockade (NMB) management (n = 35, 68.6%). Use of NMB during temperature control induction was variable; 61.7% (n = 29) of sites induced paralysis less than 20% of the time. While most institutional protocols (n = 11, 83.3%) commented on the importance of early initiation of temperature control, this was incongruent with the largest reported barrier, which was clinical nihilism regarding the importance of early temperature control initiation (n = 30, 62.5%). Within the ICECAP trial database, 1 in 2 patients were treated with NMB however, use of NMB and time to initiation of temperature control device varied widely between sites.

CONCLUSION

Amongst ICECAP trial sites, there was significant variability in resources, methods, and barriers for early temperature control initiation. Defining and standardizing high-quality temperature control must be prioritized, as it may impact the interpretation of past and current clinical trial findings.

[Neuromuscular Blockade in the Critically Ill]

The management of sedation in intensive care medicine has changed substantially in the last few years. Neuromuscular blocking agents (NMBA) are only rarely indicated in modern intensive care medicine. In this review, the mechanism of action, potential side effects, and special considerations for the application of NMBA to critically ill patients will be discussed. We further present the rationale for the use of NMBA for the remaining indications, such as endotracheal intubation, selected cases of severe acute respiratory distress syndrome, and shivering during temperature control after cardiac arrest. The review will close with a description of potential side effects of NMBA use in the intensive care setting, such as awareness, acquired skeletal muscle weakness as well as corneal injuries, and how monitoring of sedation and peripheral muscle blockade may be handled.

Temperature Control in the Era of Personalized Medicine: Knowledge Gaps, Research Priorities, and Future Directions

Hypoxic-ischemic brain injury (HIBI) is the leading cause of death and disability after cardiac arrest. To date, temperature control is the only intervention shown to improve neurologic outcomes in patients with HIBI. Despite robust preclinical evidence supporting hypothermia as neuroprotective therapy after cardiac arrest, there remains clinical equipoise regarding optimal core temperature, therapeutic window, and duration of therapy. Current guidelines recommend continuous temperature monitoring and active fever prevention for at least 72 h and additionally note insufficient evidence regarding temperature control targeting 32 °C-36 °C. However, population-based thresholds may be inadequate to support the metabolic demands of ischemic, reperfused, and dysregulated tissue. Promoting a more personalized approach with individualized targets has the potential to further improve outcomes. This review will analyze current knowledge and evidence, address research priorities, explore the components of high-quality temperature control, and define critical future steps that are needed to advance patient-centered care for cardiac arrest survivors.

Neuromuscular Blocking Agent Use in Critical Care Transport Not Associated With Intubation

OBJECTIVE

Variable indications exist for neuromuscular blocking agents (NMBAs) in the critical care transport setting beyond facilitation of intubation.

METHODS

This retrospective cohort study included adult patients (≥ 18 years) who underwent critical care transport from July 1, 2020, to May 2, 2023, and received NMBAs during transport that was not associated with intubation. The primary outcome was the indication for NMBA administration. Secondary outcomes included the characterization of NMBA use, mean Richmond Agitation Sedation Scale score before NMBA administration, sedation strategy used, and continuation of NMBAs within 48 hours of hospital admission.

RESULTS

One hundred twenty-six patients met the inclusion criteria. The most common indication for NMBA administration was ventilator dyssynchrony (n = 71, 56.4%). The majority of patients received rocuronium during transport (n = 113, 89.7%). The mean pre-NMBA Richmond Agitation Sedation Scale score was -3.7 ± 2.4. The most common sedation strategy was a combination of continuous infusion and bolus sedatives (76.2%). One hundred (79.4%) patients had sedation changes in response to NMBA administration. Seventy-two (57.1%) received NMBAs during the first 48 hours of their intensive care unit admission.

CONCLUSION

NMBAs were frequently administered for ventilator dyssynchrony and continuation of prior therapy. Optimization opportunities exist to ensure adequate deep sedation and reassessment of NMBA indication.

Critical Care Management of Patients After Cardiac Arrest: A Scientific Statement from the American Heart Association and Neurocritical Care Society

The critical care management of patients after cardiac arrest is burdened by a lack of high-quality clinical studies and the resultant lack of high-certainty evidence. This results in limited practice guideline recommendations, which may lead to uncertainty and variability in management. Critical care management is crucial in patients after cardiac arrest and affects outcome. Although guidelines address some relevant topics (including temperature control and neurological prognostication of comatose survivors, 2 topics for which there are more robust clinical studies), many important subject areas have limited or nonexistent clinical studies, leading to the absence of guidelines or low-certainty evidence. The American Heart Association Emergency Cardiovascular Care Committee and the Neurocritical Care Society collaborated to address this gap by organizing an expert consensus panel and conference. Twenty-four experienced practitioners (including physicians, nurses, pharmacists, and a respiratory therapist) from multiple medical specialties, levels, institutions, and countries made up the panel. Topics were identified and prioritized by the panel and arranged by organ system to facilitate discussion, debate, and consensus building. Statements related to postarrest management were generated, and 80% agreement was required to approve a statement. Voting was anonymous and web based. Topics addressed include neurological, cardiac, pulmonary, hematological, infectious, gastrointestinal, endocrine, and general critical care management. Areas of uncertainty, areas for which no consensus was reached, and future research directions are also included. Until high-quality studies that inform practice guidelines in these areas are available, the expert panel consensus statements that are provided can advise clinicians on the critical care management of patients after cardiac arrest.

Critical Care Management of Patients After Cardiac Arrest: A Scientific Statement From the American Heart Association and Neurocritical Care Society

The critical care management of patients after cardiac arrest is burdened by a lack of high-quality clinical studies and the resultant lack of high-certainty evidence. This results in limited practice guideline recommendations, which may lead to uncertainty and variability in management. Critical care management is crucial in patients after cardiac arrest and affects outcome. Although guidelines address some relevant topics (including temperature control and neurological prognostication of comatose survivors, 2 topics for which there are more robust clinical studies), many important subject areas have limited or nonexistent clinical studies, leading to the absence of guidelines or low-certainty evidence. The American Heart Association Emergency Cardiovascular Care Committee and the Neurocritical Care Society collaborated to address this gap by organizing an expert consensus panel and conference. Twenty-four experienced practitioners (including physicians, nurses, pharmacists, and a respiratory therapist) from multiple medical specialties, levels, institutions, and countries made up the panel. Topics were identified and prioritized by the panel and arranged by organ system to facilitate discussion, debate, and consensus building. Statements related to postarrest management were generated, and 80% agreement was required to approve a statement. Voting was anonymous and web based. Topics addressed include neurological, cardiac, pulmonary, hematological, infectious, gastrointestinal, endocrine, and general critical care management. Areas of uncertainty, areas for which no consensus was reached, and future research directions are also included. Until high-quality studies that inform practice guidelines in these areas are available, the expert panel consensus statements that are provided can advise clinicians on the critical care management of patients after cardiac arrest.

Association between neuromuscular blocking agent use and outcomes among out-of-hospital cardiac arrest patients treated with extracorporeal cardiopulmonary resuscitation and target temperature management: A secondary analysis of the SAVE-J II study

Background

Neuromuscular blocking agents are used to control shivering in cardiac arrest patients treated with target temperature management. However, their effect on outcomes in patients treated with extracorporeal cardiopulmonary resuscitation is unclear.

Methods

This study was a secondary analysis of the SAVE-J II study, a retrospective multicenter study of 2175 out-of-hospital cardiac arrest patients treated with extracorporeal cardiopulmonary resuscitation in Japan. We classified patients into those who received neuromuscular blocking agents and those who did not and compared in-hospital mortality and incidence rates of favorable neurological outcome and in-hospital pneumonia between the groups using multivariable regression models and stabilized inverse probability weighting with propensity scores.

Results

Six hundred sixty patients from the SAVE-J II registry were analyzed. Neuromuscular blocking agents were used in 451 patients (68.3%). After adjusting for potential confounders, neuromuscular blocking agents use was not significantly associated with in-hospital mortality (aHR 0.88; 95% CI, 0.67-1.14), favorable neurological outcome (aOR 0.85; 95% CI, 0.60-1.11), or pneumonia (aOR 1.52; 95% CI, 0.85-2.71). The results for in-hospital mortality (aHR 0.89; 95% CI, 0.64-1.25), favorable neurological outcome (aOR 0.94; 95% CI, 0.59-1.48) and pneumonia (aOR 1.59; 95% CI, 0.74-3.41) were similar after weighting was performed.

Conclusions

Although data on the rationale for using neuromuscular blocking agents were unavailable, their use was not significantly associated with outcomes in out-of-hospital cardiac arrest patients treated with extracorporeal cardiopulmonary resuscitation and targeted temperature management. Neuromuscular blocking agents should be used based on individual clinical indications.

The Identification of Subsequent Events Following Out-of-Hospital Cardiac Arrests with Targeted Temperature Management

Background

Out-of-hospital cardiac arrest (OHCA) is a critical issue due to poor neurological outcomes and high mortality rate. Severe ischemia and reperfusion injury often occur after cardiopulmonary resuscitation (CPR) and return of spontaneous circulation (ROSC). Targeted temperature management (TTM) has been shown to reduce neurological complications among OHCA survivors. However, it is unclear how "time-to-cool" influences clinical outcomes. In this study, we investigated the optimal timing to reach target temperature after cardiac arrest and ROSC.

Methods

A total of 568 adults with OHCA and ROSC were admitted for targeted hypothermia assessment. Several events were predicted, including pneumonia, septic shock, gastrointestinal (GI) bleeding, and death.

Results

One hundred and eighteen patients [70 men (59.32%); 48 women (40.68%)] were analyzed for clinical outcomes. The duration of CPR after ROSC was significantly associated with pneumonia, septic shock, GI bleeding, and mortality after TTM (all p < 0.001). The duration of CPR was also positively correlated with poor outcomes on the Elixhauser score (p = 0.001), APACHE II score (p = 0.008), Cerebral Performance Categories (CPC) scale (p < 0.001), and Glasgow Coma Scale (GCS) score (p < 0.001). There was a significant association between the duration of CPR and time-to-cool of TTM after ROSC (Pearson value = 0.447, p = 0.001). Pneumonia, septic shock, GI bleeding, and death were significantly higher in the patients who underwent TTM with a time-to-cool exceeding 360 minutes (all p < 0.001).

Conclusions

For cardiac arrest patients, early cooling has clear benefits in reducing clinical sequelae. Clinical outcomes could be improved by improving the time to reach target temperature and feasibility for critically ill patients.

Sedation and shivering management after cardiac arrest

Management of sedation and shivering during targeted temperature management (TTM) after cardiac arrest is limited by a dearth of high-quality evidence to guide clinicians. Data from general intensive care unit (ICU) populations can likely be extrapolated to post-cardiac arrest patients, but clinicians should be mindful of key differences that exist between these populations. Most importantly, the goals of sedation after cardiac arrest are distinct from other ICU patients and may also involve suppression of shivering during TTM. Drug metabolism and clearance are altered considerably during TTM when a low goal temperature is used, which can delay accurate neuroprognostication. When neuromuscular blockade is used to prevent shivering, sedation should be deep enough to prevent awareness and providers should be aware that this can mask clinical manifestations of seizures. However, excessively deep or prolonged sedation is associated with complications including delirium, infections, increased duration of ventilatory support, prolonged ICU length of stay, and delays in neuroprognostication. In this manuscript, we review sedation and shivering management best practices in the post-cardiac arrest patient population.

General Critical Care, Temperature Control, and End-of-Life Decision Making in Patients Resuscitated from Cardiac Arrest

Cardiac arrest affects millions of people per year worldwide. Although advances in cardiopulmonary resuscitation and intensive care have improved outcomes over time, neurologic impairment and multiple organ dysfunction continue to be associated with a high mortality rate. The pathophysiologic mechanisms underlying the post-resuscitation disease are complex, and a coordinated, evidence-based approach to post-resuscitation care has significant potential to improve survival. Critical care management of patients resuscitated from cardiac arrest focuses on the identification and treatment of the underlying cause(s), hemodynamic and respiratory support, organ protection, and active temperature control. This review provides a state-of-the-art appraisal of critical care management of the post-cardiac arrest patient.

Hypothermia versus Normothermia after Out-of-Hospital Cardiac Arrest; The effect on post-intervention serum concentrations of sedatives and analgesics and time to awakening

BACKGROUND

This study investigated the association of two levels of targeted temperature management (TTM) after out-of-hospital cardiac arrest (OHCA) with administered doses of sedative and analgesic drugs, serum concentrations, and the effect on time to awakening.

METHODS

This substudy of the TTM2-trial was conducted at three centers in Sweden, with patients randomized to either hypothermia or normothermia. Deep sedation was mandatory during the 40-hour intervention. Blood samples were collected at the end of TTM and end of protocolized fever prevention (72 hours). Samples were analysed for concentrations of propofol, midazolam, clonidine, dexmedetomidine, morphine, oxycodone, ketamine and esketamine. Cumulative doses of administered sedative and analgesic drugs were recorded.

RESULTS

Seventy-one patients were alive at 40 hours and had received the TTM-intervention according to protocol. 33 patients were treated at hypothermia and 38 at normothermia. There were no differences between cumulative doses and concentration and of sedatives/analgesics between the intervention groups at any timepoint. Time until awakening was 53 hours in the hypothermia group compared to 46 hours in the normothermia group (p=0.09).

CONCLUSION

This study of OHCA patients treated at normothermia versus hypothermia found no significant differences in dosing or concentration of sedatives or analgesic drugs in blood samples drawn at the end of the TTM intervention, or at end of protocolized fever prevention, nor the time to awakening.

Targeted Temperature Management in Cardiac Arrest: An Updated Narrative Review

The established benefits of cooling along with development of sophisticated methods to safely and precisely induce, maintain, monitor, and reverse hypothermia have led to the development of targeted temperature management (TTM). Early trials in human subjects showed that hypothermia conferred better neurological outcomes when compared to normothermia among survivors of cardiac arrest, leading to guidelines recommending targeted hypothermia in this patient population. Multiple studies have sought to explore and compare the benefit of hypothermia in various subgroups of patients, such as survivors of out-of-hospital cardiac arrest versus in-hospital cardiac arrest, and survivors of an initial shockable versus non-shockable rhythm. Larger and more recent trials have shown no statistically significant difference in neurological outcomes between patients with targeted hypothermia and targeted normothermia; further, aggressive cooling is associated with a higher incidence of multiple systemic complications. Based on this data, temporal trends have leaned towards using a lenient temperature target in more recent times. Current guidelines recommend selecting and maintaining a constant target temperature between 32 and 36 °C for those patients in whom TTM is used (strong recommendation, moderate-quality evidence), as soon as possible after return of spontaneous circulation is achieved and airway, breathing (including mechanical ventilation), and circulation are stabilized. The comparative benefit of lower (32-34 °C) versus higher (36 °C) temperatures remains unknown, and further research may help elucidate this. Any survivor of cardiac arrest who is comatose (defined as unarousable unresponsiveness to external stimuli) should be considered as a candidate for TTM regardless of the initial presenting rhythm, and the decision to opt for targeted hypothermia versus targeted normothermia should be made on a case-by-case basis.

Cardiac Arrest Treatment Center Differences in Sedation and Analgesia Dosing During Targeted Temperature Management

BACKGROUND

Sedation and analgesia are recommended during targeted temperature management (TTM) after cardiac arrest, but there are few data to provide guidance on dosing to bedside clinicians. We evaluated differences in patient-level sedation and analgesia dosing in an international multicenter TTM trial to better characterize current practice and clinically important outcomes.

METHODS

A total 950 patients in the international TTM trial were randomly assigned to a TTM of 33 °C or 36 °C after resuscitation from cardiac arrest in 36 intensive care units. We recorded cumulative doses of sedative and analgesic drugs at 12, 24, and 48 h and normalized to midazolam and fentanyl equivalents. We compared number of medications used, dosing, and titration among centers by using multivariable models, including common severity of illness factors. We also compared dosing with time to awakening, incidence of clinical seizures, and survival.

RESULTS

A total of 614 patients at 18 centers were analyzed. Propofol (70%) and fentanyl (51%) were most frequently used. The average dosages of midazolam and fentanyl equivalents were 0.13 (0.07, 0.22) mg/kg/h and 1.16 (0.49, 1.81) µg/kg/h, respectively. There were significant differences in number of medications (p < 0.001), average dosages (p < 0.001), and titration at all time points between centers (p < 0.001), and the outcomes of patients in these centers were associated with all parameters described in the multivariate analysis, except for a difference in the titration of sedatives between 12 and 24 h (p = 0.40). There were associations between higher dosing at 48 h (p = 0.003, odds ratio [OR] 1.75) and increased titration of analgesics between 24 and 48 h (p = 0.005, OR 4.89) with awakening after 5 days, increased titration of sedatives between 24 and 48 h with awakening after 5 days (p < 0.001, OR > 100), and increased titration of sedatives between 24 and 48 h with a higher incidence of clinical seizures in the multivariate analysis (p = 0.04, OR 240). There were also significant associations between decreased titration of analgesics and survival at 6 months in the multivariate analysis (p = 0.048).

CONCLUSIONS

There is significant variation in choice of drug, dosing, and titration when providing sedation and analgesics between centers. Sedation and analgesia dosing and titration were associated with delayed awakening, incidence of clinical seizures, and survival, but the causal relation of these findings cannot be proven.

Withdrawal of life-sustaining therapy in intensive care unit patients following out-of-hospital cardiac arrest: An Australian metropolitan ICU experience

BACKGROUND

Withdrawal of life-sustaining therapy is a common phenomenon following out-of-hospital cardiac arrest. The clinical practices surrounding withdrawal of life-sustaining therapy remain unclear and warrant further inspection due to their reported impact on post-cardiac arrest mortality.

OBJECTIVES

To determine factors associated with withdrawal of life-sustaining therapy (WLST) in intensive care unit (ICU) patients following out-of-hospital cardiac arrest (OHCA).

METHODS

A retrospective review of ICU patients' clinical records following OHCA was conducted from January 2010 to December 2015. Demographic features, cardiac arrest characteristics, and targeted temperature management practices were compared between patients with and without WLST. We dichotomised WLST into early (ICU length of stay <72 h) and late (ICU length of stay ≥72 h). Factors independently associated with WLST were determined by multivariable binary logistic regression.

RESULTS

The study cohort included 260 post-OHCA ICU patients. The mean age was 58 years, and majority were males (178, 68%); 145 (56%) underwent WLST, with the majority undergoing early WLST (89, 61%). Status myoclonus was the strongest independent factor associated with early WLST (OR 42.53, 95% CI 4.97-363.60; p < 0.001). Glasgow Coma Scale (GCS) motor response of <4 on day three post-OHCA was the strongest factor associated with delayed WLST (OR 48.76, 95% CI 11.87-200.27; p < 0.0001).

CONCLUSION

The majority of deaths in ICU patients post-OHCA occurred following early WLST. Status myoclonus and a GCS motor response of <4 on day three post-OHCA are independently associated with WLST.

Neuromuscular Blockade for Cardiac Arrest Patients Treated With Targeted Temperature Management: A Systematic Review and Meta-Analysis

Background: Neuromuscular-blocking agents (NMBA) are often administered to control shivering in comatose cardiac arrest (CA) survivors during targeted temperature management (TTM) management. Thus, we performed a systematic review and meta-analysis to investigate the effectiveness and safety of NMBA in such a patient population. Methods: We searched for relevant studies in PubMed, Embase, and the Cochrane Library until 15 Jul 2021. Studies were included if they reported data on any of the predefined outcomes in adult comatose CA survivors managed with any NMBA regimens. The primary outcomes were mortality and neurological outcome. Results were expressed as odds ratio (OR) or mean difference (MD) with an accompanying 95% confidence interval (CI). Heterogeneity, sensitivity analysis, and publication bias were also investigated to test the robustness of the primary outcome. Data Synthesis: We included 12 studies (3 randomized controlled trials and nine observational studies) enrolling 11,317 patients. These studies used NMBA in three strategies: prophylactic NMBA, bolus NMBA if demanded, or managed without NMBA. Pooled analysis showed that CA survivors with prophylactic NMBA significantly improved both outcomes of mortality (OR 0.74; 95% CI 0.64-0.86; I 2 = 41%; p < 0.0001) and neurological outcome (OR 0.53; 95% CI 0.37-0.78; I 2 = 59%; p = 0.001) than those managed without NMBA. These results were confirmed by the sensitivity analyses and subgroup analyses. Only a few studies compared CA survivors receiving continuous versus bolus NMBA if demanded strategies and the pooled results showed no benefit in the primary outcomes between the two groups. Conclusion: Our results showed that using prophylactic NMBA strategy compared to the absence of NMBA was associated with improved mortality and neurologic outcome in CA patients undergoing TTM. However, more high-quality randomized controlled trials are needed to confirm our results.

Contemporary targeted temperature management: Clinical evidence and controversies

Advancements in cardiac arrest and post-cardiac arrest care have led to improved survival to hospital discharge. While survival to hospital discharge is an important clinical outcome, neurologic recovery is also a priority. With the advancement of targeted temperature management (TTM), the American Heart Association guidelines for post-cardiac arrest care recommend TTM in patients who remain comatose after return of spontaneous circulation (ROSC). Recently, the TTM2 randomized controlled trial found no significant difference in neurologic function and mortality at 6-months between traditional hypothermia to 33°C versus 37.5°C. While TTM has been evaluated for decades, current literature suggests that the use of TTM to 33° when compared to a protocol of targeted normothermia does not result in improved outcomes. Instead, perhaps active avoidance of fever may be most beneficial. Extracorporeal cardiopulmonary resuscitation and membrane oxygenation can provide a means of both hemodynamic support and TTM after ROSC. This review aims to describe the pathophysiology, physiologic aspects, clinical trial evidence, changes in post-cardiac arrest care, potential risks, as well as controversies of TTM.

The Use of Neuromuscular Blockers to Prevent Shivering in the Setting of Postcardiac Arrest Targeted Temperature Management: A Narrative Review of an Off-Label Indication

Targeted temperature management (TTM) has become a standard of care over the past two decades for the improvement in neurologic function and mortality in postcardiac arrest patients. There are various mechanisms by which hypothermia helps to improve these outcomes, one of which is by reducing oxygen requirements. Less established is the use of nondepolarizing neuromuscular blockers (NMBs) to prevent shivering during TTM. Shivering can be disadvantageous in this setting as it increases oxygen requirements, which TTM is actively trying to decrease, in an already oxygen-deprived system as well as generates heat making it difficult to maintain hypothermia. Whether NMBs can improve these outcomes is conflicting in the currently available literature and there lacks a consensus on their role in shivering management. The pharmacokinetic and pharmacodynamic responses of these agents may be altered in hypothermic patients, therefore, their standard of monitoring may be unreliable. The accurate dosing and administration of these agents also remain unclear, further complicated by the lack of a standard use protocol. Various studies have been conducted regarding the use of NMBs to prevent shivering in postcardiac arrest patients undergoing TTM; however, it remains an off-label indication requiring further investigation.

Impact of benzodiazepines on time to awakening in post cardiac arrest patients

AIM

Although guidelines recommend use of short acting sedation after cardiac arrest, there is significant practice variation. We examined whether benzodiazepine use is associated with delayed awakening in this population.

METHODS

We performed a retrospective single center study including comatose patients treated after in- or out-of-hospital cardiac arrest from January 2010 to September 2019. We excluded patients who awakened within 6 h of arrest, those who arrested due to trauma or neurological event, those with nonsurvivable primary brain injury and those with refractory shock. Our primary exposure of interest was high-dose benzodiazepine (>10 mg of midazolam equivalents per day) administration in the first 72-h post arrest. Our primary outcome was time to awakening. We used Cox regression to test for an independent association between exposure and outcome after controlling for biologically plausible covariates.

RESULTS

Overall, 2778 patients presented during the study period, 621 met inclusion criteria and 209 (34%) awakened after a median of 4 [IQR 3-7] days. Patients who received high-dose benzodiazepines awakened later than those who did not (5 [IQR 3-11] vs. 3 [IQR 3-6] days, P = 0.004). In adjusted regression, high-dose benzodiazepine exposure was independently associated with delayed awakening (adjusted hazard ratio 0.63 (95% CI 0.43-0.92)). Length of stay, awakening to discharge, and duration of mechanical ventilation were similar across groups.

CONCLUSION

High-dose benzodiazepine exposure is independently associated with delayed awakening in comatose survivors of cardiac arrest.

Targeted temperature management and early neuro-prognostication after cardiac arrest

Targeted temperature management (TTM) is a recommended neuroprotective intervention for coma after out-of-hospital cardiac arrest (OHCA). However, controversies exist concerning the proper implementation and overall efficacy of post-CA TTM, particularly related to optimal timing and depth of TTM and cooling methods. A review of the literature finds that optimizing and individualizing TTM remains an open question requiring further clinical investigation. This paper will summarize the preclinical and clinical trial data to-date, current recommendations, and future directions of this therapy, including new cooling methods under investigation. For now, early induction, maintenance for at least 24 hours, and slow rewarming utilizing endovascular methods may be preferred. Moreover, timely and accurate neuro-prognostication is valuable for guiding ethical and cost-effective management of post-CA coma. Current evidence for early neuro-prognostication after TTM suggests that a combination of initial prediction models, biomarkers, neuroimaging, and electrophysiological methods is the optimal strategy in predicting neurological functional outcomes.

European Resuscitation Council and European Society of Intensive Care Medicine guidelines 2021: post-resuscitation care

The European Resuscitation Council (ERC) and the European Society of Intensive Care Medicine (ESICM) have collaborated to produce these post-resuscitation care guidelines for adults, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include the post-cardiac arrest syndrome, diagnosis of cause of cardiac arrest, control of oxygenation and ventilation, coronary reperfusion, haemodynamic monitoring and management, control of seizures, temperature control, general intensive care management, prognostication, long-term outcome, rehabilitation and organ donation.

European Resuscitation Council and European Society of Intensive Care Medicine Guidelines 2021: Post-resuscitation care

The European Resuscitation Council (ERC) and the European Society of Intensive Care Medicine (ESICM) have collaborated to produce these post-resuscitation care guidelines for adults, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include the post-cardiac arrest syndrome, diagnosis of cause of cardiac arrest, control of oxygenation and ventilation, coronary reperfusion, haemodynamic monitoring and management, control of seizures, temperature control, general intensive care management, prognostication, long-term outcome, rehabilitation, and organ donation.

Neuroprotective Treatment of Postanoxic Encephalopathy: A Review of Clinical Evidence

Postanoxic encephalopathy is the key determinant of death or disability after successful cardiopulmonary resuscitation. Animal studies have provided proof-of-principle evidence of efficacy of divergent classes of neuroprotective treatments to promote brain recovery. However, apart from targeted temperature management (TTM), neuroprotective treatments are not included in current care of patients with postanoxic encephalopathy after cardiac arrest. We aimed to review the clinical evidence of efficacy of neuroprotective strategies to improve recovery of comatose patients after cardiac arrest and to propose future directions. We performed a systematic search of the literature to identify prospective, comparative clinical trials on interventions to improve neurological outcome of comatose patients after cardiac arrest. We included 53 studies on 21 interventions. None showed unequivocal benefit. TTM at 33 or 36°C and adrenaline (epinephrine) are studied most, followed by xenon, erythropoietin, and calcium antagonists. Lack of efficacy is associated with heterogeneity of patient groups and limited specificity of outcome measures. Ongoing and future trials will benefit from systematic collection of measures of baseline encephalopathy and sufficiently powered predefined subgroup analyses. Outcome measurement should include comprehensive neuropsychological follow-up, to show treatment effects that are not detectable by gross measures of functional recovery. To enhance translation from animal models to patients, studies under experimental conditions should adhere to strict methodological and publication guidelines.

Intermittent versus continuous neuromuscular blockade during target temperature management after cardiac arrest: A nationwide observational study

PURPOSE

Whether intermittent or continuous neuromuscular-blocking agents (NMBAs) would be appropriate during target temperature management (TTM) after cardiac arrest remains unclear.

MATERIALS AND METHODS

In this retrospective cohort study, we utilized the Japanese Diagnosis Procedure Combination inpatient database from July 2010 to March 2018 and identified patients who received NMBAs during TTM after cardiac arrest on the day of admission. We compared the in-hospital mortality between the propensity-score-matched intermittent and continuous NMBA groups.

RESULTS

We identified 5584 eligible patients; 1488 received intermittent NMBAs and 4096 received continuous NMBAs. After propensity score matching, there was no significant difference in the in-hospital mortality between the intermittent and continuous NMBA groups (32.9% vs. 33.1%; odds ratio, 0.98; 95% confidence interval, 0.82-1.18). In subgroup analyses, in-hospital mortality of the continuous NMBA group was significantly higher than that of the intermittent NMBA group in patients aged ≥65 years (p for interaction = 0.021).

CONCLUSIONS

This large retrospective study did not suggest that intermittent NMBAs may be inferior to continuous NMBAs in terms of mortality reduction in the overall population receiving TTM for cardiac arrest. However, continuous NMBAs may be inferior to intermittent NMBAs for reducing mortality in elderly patients.

Consensus Statement on Analgo-sedation in Neurocritical Care and Review of Literature

Aim and objective

Our main objective in developing this consensus is to bring together a set of most agreed-upon statements from a panel of global experts that would act as a guide for clinicians working in neurocritical care units (NCCUs).

Background

Given the physiological benefits of analgo-sedation in the NCCU, there is little information on their tailoring in the NCCU. This lack of evidence and guidelines on the use of sedation and analgesia in patients with neurological injury leads to a variation in clinical care based on patient requirements and institutional protocols.

Review results

Thirty-nine international experts agreed to be a member of this consensus panel. A Delphi method based on a Web-based questionnaire developed with Google Forms on a secure institute server was used to seek opinions of experts. Questions were related to sedation and analgesia in the neurocritical care unit. A predefined threshold of agreement was established as 70% to support any recommendation, strong, moderate, or weak. No recommendations were made below this threshold. Responses were collected from all the experts, summated, and expressed as percentage (%). After three rounds, consensus could be reached for 6 statements related to analgesia and 5 statements related to sedation. Consensus could not be reached for 10 statements related to analgesia and 5 statements related to sedation.

Conclusion

This global consensus statement may help in guiding practitioners in clinical decision-making regarding analgo-sedation in the NCCUs, thereby helping in improving patient recovery profiles.

Clinical significance

In the lack of high-level evidence, the recommendations may be seen as the current best clinical practice.

How to cite this article

Prabhakar H, Tripathy S, Gupta N, Singhal V, Mahajan C, Kapoor I, et al. Consensus Statement on Analgo-sedation in Neurocritical Care and Review of Literature. Indian J Crit Care Med 2021;25(2):126–133.

The cold truth about postcardiac arrest targeted temperature management: 33°C vs. 36°C

This article provides nurses with up-to-date evidence to empower them in contributing to the 33°C versus 36°C discussion in postcardiac arrest targeted temperature management (TTM). Presented in debate format, this article addresses the pros and cons of various target temperatures, examines the evidence around TTM, and applies it to clinical scenarios.

Association Between Target Temperature Variability and Neurologic Outcomes for Patients Receiving Targeted Temperature Management at 36°C After Cardiac Arrest: A Retrospective Cohort Study

Maintaining strict temperature control during the maintenance phase of targeted temperature management (TTM) after cardiac arrest may be an important component of clinical care. Temperature variability outside of the goal temperature range may lessen the benefit of TTM and worsen neurologic outcomes. The purpose of this retrospective study of 186 adult patients (70.4% males, mean age 53.8 ± 15.7 years) was to investigate the relationship between body temperature variability (at least one body temperature measurement outside of 36°C ± 0.5°C) during the maintenance phase of TTM at 36°C after cardiac arrest and neurologic outcome at hospital discharge. Patients with temperature variability (n = 124 [66.7%]) did not have significantly higher odds of poor neurologic outcome compared with those with no temperature variability (odds ratio [OR] = 1.01, 95% confidence interval [CI] = 0.36-2.82). Use of neuromuscular blocking agents (NMBAs) and having an initial shockable rhythm were associated with both higher odds of good neurologic outcome (shockable rhythm: OR = 10.77, 95% CI = 4.30-26.98; NMBA use: OR = 4.54, 95% CI = 1.34-15.40) and survival to hospital discharge (shockable rhythm: OR = 5.90, 95% CI = 2.65-13.13; NMBA use: OR = 3.03, 95% CI = 1.16-7.90). In this cohort of postcardiac arrest comatose survivors undergoing TTM at 36°C, having temperature variability during maintenance phase did not significantly impact neurologic outcome or survival.

Control of Shivering During Targeted Temperature Management

Targeted temperature management (TTM) is used frequently in patients with a variety of diseases, especially those who have experienced brain injury and/or cardiac arrest. Shivering is one of the main adverse effects of TTM that can often limit its implementation and efficacy. Shivering is the body's natural response to hypothermia and its deleterious effects can negate the benefits of TTM. The purpose of this article is to provide an overview of TTM strategies and shivering management.

High Quality Targeted Temperature Management (TTM) After Cardiac Arrest

Targeted temperature management (TTM) is a complex intervention used with the aim of minimizing post-anoxic injury and improving neurological outcome after cardiac arrest. There is large variability in the devices used to achieve cooling and in protocols (e.g., for induction, target temperature, maintenance, rewarming, sedation, management of post-TTM fever). This variability can explain the limited benefits of TTM that have sometimes been reported. We therefore propose the concept of “high-quality TTM” as a way to increase the effectiveness of TTM and standardize its use in future interventional studies.

Postresuscitation Care after Out-of-hospital Cardiac Arrest: Clinical Update and Focus on Targeted Temperature Management

Out-of-hospital cardiac arrest is a major cause of mortality and morbidity worldwide. With the introduction of targeted temperature management more than a decade ago, postresuscitation care has attracted increased attention. In the present review, we discuss best practice hospital management of unconscious out-of-hospital cardiac arrest patients with a special focus on targeted temperature management. What is termed post-cardiac arrest syndrome strikes all organs and mandates access to specialized intensive care. All patients need a secured airway, and most patients need hemodynamic support with fluids and/or vasopressors. Furthermore, immediate coronary angiography and percutaneous coronary intervention, when indicated, has become an essential part of the postresuscitation treatment. Targeted temperature management with controlled sedation and mechanical ventilation is the most important neuroprotective strategy to take. Targeted temperature management should be initiated as quickly as possible, and according to international guidelines, it should be maintained at 32° to 36°C for at least 24 h, whereas rewarming should not increase more than 0.5°C per hour. However, uncertainty remains regarding targeted temperature management components, warranting further research into the optimal cooling rate, target temperature, duration of cooling, and the rewarming rate. Moreover, targeted temperature management is linked to some adverse effects. The risk of infection and bleeding is moderately increased, as is the risk of hypokalemia and magnesemia. Circulation needs to be monitored invasively and any deviances corrected in a timely fashion. Outcome prediction in the individual patient is challenging, and a self-fulfilling prophecy poses a real threat to early prognostication based on clinical assessment alone. Therefore, delayed and multimodal prognostication is now considered a key element of postresuscitation care. Finally, modern postresuscitation care can produce good outcomes in the majority of patients but requires major diagnostic and therapeutic resources and specific training. Hence, recent international guidelines strongly recommend the implementation of regional prehospital resuscitation systems with integrated and specialized cardiac arrest centers.

Continuous neuromuscular blockade infusion for out-of-hospital cardiac arrest patients treated with targeted temperature management: A multicenter randomized controlled trial

Introduction

The aim of this trial was to investigate the effect of a continuous infusion of a neuromuscular blockade (NMB) in comatose out-of-hospital cardiac arrest (OHCA) subjects who underwent targeted temperature management (TTM).

Methods

In this open-label, multicenter trial, subjects resuscitated from OHCA were randomly assigned to receive either NMB (38 subjects) or placebo (43 subjects) for 24 hours. Sedatives and analgesics were given according to the protocol of each hospital during TTM. The primary outcome was serum lactate levels at 24 hours after drug infusion. The secondary outcomes included in-hospital mortality, a poor neurological outcome at hospital discharge, changes in lactate levels, changes in the PaO₂:FiO₂ ratio over time and muscle weakness as assessed by the Medical Research Council (MRC) scale.

Results

Eighty-one subjects (NMB group: median age, 65.5 years, 30 male patients; placebo group: median age, 61.0 years, 29 male patients) were enrolled in this trial. No difference in the serum lactate level at 24 hours was observed between the NMB (2.8 [1.2–4.0]) and placebo (3.6 [1.8–5.2]) groups (p = 0.238). In-hospital mortality and a poor neurologic outcome at discharge did not differ between the two groups. No significant difference in the PaO₂:FiO₂ ratio over time (p = 0.321) nor the MRC score (p = 0.474) was demonstrated.

Conclusions

In OHCA subjects who underwent TTM, a continuous infusion of NMB did not reduce lactate levels and did not improve survival or neurological outcome at hospital discharge. Our results indicated a limited potential for the routine use of NMB during early TTM. However, this trial may be underpowered to detect clinical differences, and future research should be conducted.