Progress in shivering control

The impact of magnesium on shivering incidence in cardiac surgery patients: A systematic review

Background and objective

This scientific review involves a sequential analysis of randomized trial research focused on the incidence of shivering in patients undergoing cardiac surgery. The study conducted a comprehensive search of different databases, up to the end of 2020. Only randomized trials comparing magnesium administration with either placebo or no treatment in patients expected to experience shivering were included. The primary objective was to evaluate shivering occurrence, distinguishing between patients receiving general anesthesia and those not. Secondary outcomes included serum magnesium concentrations, intubation time, post-anesthesia care unit stay, hospitalization duration, and side effects. Data collection included patient demographics and various factors related to magnesium administration.

Material and methods

This scientific review analyzed 64 clinical trials meeting inclusion criteria, encompassing a total of 4303 patients. Magnesium was administered via different routes, primarily intravenous, epidural, and intraperitoneal, and compared against placebo or control. Data included demographics, magnesium dosage, administration method, and outcomes. Heterogeneity was assessed using the I2 statistic. Some studies were excluded due to unavailability of data or non-responsiveness from authors.

Result

and discussion: Out of 2546 initially identified articles, 64 trials were selected for analysis. IV magnesium effectively reduced shivering, with epidural and intraperitoneal routes showing even greater efficacy. IV magnesium demonstrated cost-effectiveness and a favorable safety profile, not increasing adverse effects. The exact dose-response relationship of magnesium remains unclear. The results also indicated no significant impact on sedation, extubation time, or gastrointestinal distress. However, further research is needed to determine the optimal magnesium dose and to explore its potential effects on blood pressure and heart rate, particularly regarding pruritus prevention.

Conclusion

This study highlights the efficacy of intravenous (IV) magnesium in preventing shivering after cardiac surgery. Both epidural and intraperitoneal routes have shown promising results. The safety profile of magnesium administration appears favorable, as it reduces the incidence of shivering without significantly increasing costs. However, further investigation is required to establish the ideal magnesium dosage and explore its potential effects on blood pressure, heart rate, and pruritus prevention, especially in various patient groups.

Overview of Hypothermia, Its Role in Neuroprotection, and the Application of Prophylactic Hypothermia in Traumatic Brain Injury

The current standard of practice is to maintain normothermia in traumatic brain injury (TBI) patients despite the theoretical benefits of hypothermia and numerous animal studies with promising results. While targeted temperature management or induced hypothermia to support neurological function is recommended for a select patient population postcardiac arrest, similar guidelines have not been instituted for TBI. In this review, we will examine the pathophysiology of TBI and discuss the benefits and risks of induced hypothermia in this patient population. In addition, we provide an overview of the largest randomized controlled trials testing-induced hypothermia. Our literature review on hypothermia returned a myriad of studies and trials, many of which have inconclusive results. The aim of this review was to recognize the effects of hypothermia, summarize the latest trials, address the inconsistencies, and discuss future directions for the study of hypothermia in TBI.

The effects of intravenous tramadol vs. intravenous ketamine in the prevention of shivering during spinal anesthesia: A meta-analysis of randomized controlled trials

Background

Shivering is a common complication after subarachnoid administration of local anesthetics. Intravenous ketamine and tramadol are widely available anti-shivering drugs, especially in developing settings. This meta-analysis aimed to compare the effects of intravenous ketamine vs. tramadol for post-spinal anesthesia shivering.

Materials and methods

PubMed/MEDLINE, Web of Science, Cochrane Library, Embase, and Google Scholar databases were used to search for relevant articles for this study. Mean difference (MD) with 95% confidence interval (CI) was used to analyze continuous outcomes, and risk ratio (RR) with 95% CI to analyze categorical results. The heterogeneity of the included studies was assessed using the I2 test. We utilized Review Manager 5.4.1 to perform statistical analysis.

Results

Thirteen studies involving 1,532 patients were included in this meta-analysis. Ketamine had comparable effects in preventing post-spinal anesthetics shivering [RR = 1.06; 95% CI (0.94, 1.20), P = 0.33, I ² = 77], and onset of shivering [MD = -0.10; 95%CI (- 2.68, 2.48), P = 0.94, I ² = 0%], lower incidences of nausea and vomiting [RR = 0.51; 95%CI (0.26, 0.99), P = 0.05, I ² = 67%], and lower incidences of bradycardia [RR = 0.16; 95%CI (0.05, 0.47), P = 0.001, I ² = 33%], higher incidence of hallucinations [RR = 12; 95%CI (1.58, 91.40), P = 0.02, I ² = 0%], and comparable effects regarding the incidences of hypotension [RR = 0.60; 95%CI (0.30, 1.21), P = 0.15, I ² = 54%] as compared to tramadol.

Conclusions

Intravenous ketamine and tramadol are comparable in the prevention of post-spinal anesthetic shivering. Ketamine had a better outcome with less occurrences of nausea, vomiting, and bradycardia. However, ketamine was associated with higher incidences of hallucinations than tramadol.

Energy Expenditure and Shivering Severity During Targeted Temperature Management at 36°C After Cardiac Arrest: A Case Series

Patients undergoing targeted temperature management (TTM) after cardiac arrest are at risk for shivering, which increases energy expenditure (EE) and may attenuate TTM benefits. This article reports patterns of EE for patients with and without shivering who received TTM at 36°C after cardiac arrest. Based on 96 case assessments, there were 14 occasions when more than one 15-minute interval period was required to appropriately modify the Bedside Shivering Assessment Scale (BSAS) score. Investigators noted that although higher EE was related to higher BSAS scores, there may be opportunities for earlier detection of shivering.

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.

The effects of novel α2-adrenoreceptor agonist dexmedetomidine on shivering in patients underwent caesarean section

Objective: Meperidine used to control shivering during perioperative period has associated side effects. The present study compared the safety of selective α2-adrenoreceptor agonist dexmedetomidine and meperidine for anti-shivering in primiparas after caesarean delivery under combined spinal-epidural anesthesia (CSEA).

Methods: 100 primiparas scheduled for caesarean delivery were randomly allocated to dexmedetomidine group (Group D, n=50) and meperidine positive control group (Group M, n=50). Primiparas experienced shivering that continued to cord clamping were treated with dexmedetomidine (0.5 μg/kg) or meperidine (0.5 mg/kg) after cord clamping. The primary outcome measures were incidence of nausea, vomiting, and respiratory depression. Secondary outcome measures were shivering score, vital signs including blood pressure, heart rate and O₂ saturation, tympanic temperature, and sedation score.

Results: Dexmedetomidine provided similar anti-shivering effects as meperidine in patients after caesarean delivery under CSEA, evidenced as all shivering primiparas responded to either dexmedetomidine or meperidine treatment within 15 min. However, incidence of nausea and vomiting were significantly lower after dexmedetomidine treatment, accompanied with more stable blood pressure. Dexmedetomidine also provided well regulation of tympanic temperature and good sedation.

Conclusion: Selective α₂-adrenoreceptor agonist dexmedetomidine has a better safety profile compared with meperidine for anti-shivering in primiparas undergoing caesarean delivery. Dexmedetomidine could be a better choice for anti-shivering in patients requiring caesarean section. The mechanism of anti-shivering for dexmedetomidine may relate to well regulation of temperature and good sedation.

Comparison the Effects of Oral Tizanidine and Tramadol on Intra- and Post-operative Shivering in Patients Underwent Spinal Anesthesia

Background:

Heat loss and core-to-peripheral redistribution of body heat occur in patients undergoing neuraxial anesthesia resulted to decrease of core temperature and early reach of shivering threshold. Because shivering has deleterious metabolic and cardiovascular effects, it should ideally be prevented by pharmacologic or other means. Tizanidine is an alpha-2 agonist. We evaluated the usefulness of oral tizanidine (TI) and tramadol in preventing of shivering in patients undergoing spinal anesthesia for transurethral resection of the prostate (TURP).

Materials and Methods:

Ninety patients, scheduled for TURP with spinal anesthesia, were prospectively enrolled. Patients were randomly assigned to 1 of 3 groups. 90 min before spinal anesthesia, 30 patients received 4 mg oral TI, 30 patients received 50 mg tramadol, and 30 patients received placebo as control group. Spinal anesthesia was induced at the L3–L4 or L4–L5 interspaces with 12.5 mg bupivacaine. An investigator blinded to the drugs recorded the frequency and degree of shivering.

Results:

The overall frequency and severity of shivering were significantly lower in patients treated with TI and tramadol compared to placebo (P = 0.04) (P = 0.001). There was not much difference in the nausea and vomiting of both the drugs (P = 026) (P = 011). There was no difference in hemodynamic parameters between three groups (P = 0.08) (P = 013).

Conclusions:

Oral TI and tramadol were comparable in respect to their effect in decreasing the incidence, intensity shivering when used prophylactically in patients who underwent TURP with spinal anesthesia.

Addition of Neostigmine and Tramadol to 1.5 % Lidocaine for paracervical block to reduce post-operative pain in colporrhaphy

Pain is a complex and multi-faceted human perception and several factors could dampen the pain. Therefore, we aimed to comparison of addition of neostigmine and tramadol to 1.5 % lidocaine with paracervical block in reduce of post-operative pain in colporrhaphy. This study was a randomized and double-blind clinical trial for 108 patients’ as candidate for colporrhaphy. Patients were randomly divided in three groups (Neostigmine, tramadol and control).We recorded pain in 2 and 6 and 12 hours after surgery, duration of analgesia and mean of use narcotic drug in 24 hours after surgery for all patients. Mean of narcotic drug used in 24 hours after surgery in neostigmine group was more than tramadol group(p=0/01).Pain in 2 and 6 and 12 hours after surgery in neostigmine group was more than tramadol group (p=0/01). Duration of analgesia in tramadol group was over neostigmine group and also, it was in neostigmine group was more than placebo (p=0/01).Taken together, tramadol could reduce pain in 2 and 6 and 12 hours after surgery and mean of narcotic drug used in 24 hours after surgery and increase duration of analgesia.

Therapeutic hypothermia in acute traumatic spinal cord injury

Therapeutic hypothermia is already widely acknowledged as an effective neuroprotective intervention, especially within the acute care setting in relation to conditions such as cardiac arrest and neonatal encephalopathy. Its multifactorial mechanisms of action, including lowering metabolic rate and reducing acute inflammatory cellular processes, ultimately provide protection for central nervous tissue from continuing injury following ischaemic or traumatic insult. Its clinical application within acute traumatic spinal cord injury would therefore seem very plausible, it having the potential to combat the pathophysiological secondary injury processes that can develop in the proceeding hours to days following the initial injury. As such it could offer invaluable assistance to lessen subsequent sensory, motor and autonomic dysfunction for an individual affected by this devastating condition. Yet research surrounding this intervention's applicability in this field is somewhat lacking, the majority being experimental. Despite a recent resurgence of interest, which in turn has produced encouraging results, there is a real possibility that this potentially transformational intervention for treating traumatic spinal cord injury could remain an experimental therapy and never reach clinical implementation.

Electrocardiographic changes during induced therapeutic hypothermia in comatose survivors after cardiac arrest

AIM: To assess the safety of therapeutic hypothermia (TH) concerning arrhythmias we analyzed serial electrocardiograms (ECG) during TH.

METHODS: All patients recovered from a cardiac arrest with Glasgow < 9 at admission were treated with induced mild TH to 32-34 °C. TH was obtained with cool fluid infusion or a specific intravascular device. Twelve-lead ECG before, during, and after TH, as well as ECG telemetry data was recorded in all patients. From a total of 54 patients admitted with cardiac arrest during the study period, 47 patients had the 3 ECG and telemetry data available. ECG analysis was blinded and performed with manual caliper by two independent cardiologists from blinded copies of original ECG, recorded at 25 mm/s and 10 mm/mV. Coronary care unit staff analyzed ECG telemetry for rhythm disturbances. Variables measured in ECG were rhythm, RR, PR, QT and corrected QT (QTc by Bazett formula, measured in lead v2) intervals, QRS duration, presence of Osborn’s J wave and U wave, as well as ST segment displacement and T wave amplitude in leads II, v2 and v5.

RESULTS: Heart rate went down an average of 19 bpm during hypothermia and increased again 16 bpm with rewarming (P < 0.0005, both). There was a non-significant prolongation of the PR interval during TH and a significant decrease with rewarming (P = 0.041). QRS duration significantly prolonged (P = 0.041) with TH and shortened back (P < 0.005) with rewarming. QTc interval presented a mean prolongation of 58 ms (P < 0.005) during TH and a significant shortening with rewarming of 22.2 ms (P = 0.017). Osborn or J wave was found in 21.3% of the patients. New arrhythmias occurred in 38.3% of the patients. Most frequent arrhythmia was non-sustained ventricular tachycardia (19.1%), followed by severe bradycardia or paced rhythm (10.6%), accelerated nodal rhythm (8.5%) and atrial fibrillation (6.4%). No life threatening arrhythmias (sustained ventricular tachycardia, polymorphic ventricular tachycardia or ventricular fibrillation) occurred during TH.

CONCLUSION: A 38.3% of patients had cardiac arrhythmias during TH but without life-threatening arrhythmias. A concern may rise when inducing TH to patients with long QT syndrome.

Induction of therapeutic hypothermia by pharmacological modulation of temperature-sensitive TRP channels: theoretical framework and practical considerations

Therapeutic hypothermia has emerged as a remarkably effective method of neuroprotection from ischemia and is being increasingly used in clinics. Accordingly, it is also a subject of considerable attention from a basic scientific research perspective. One of the fundamental problems, with which current studies are concerned, is the optimal method of inducing hypothermia. This review seeks to provide a broad theoretical framework for approaching this problem, and to discuss how a novel promising strategy of pharmacological modulation of the thermosensitive ion channels fits into this framework. Various physical, anatomical, physiological and molecular aspects of thermoregulation, which provide the foundation for this text, have been comprehensively reviewed and will not be discussed exhaustively here. Instead, the first part of the current review, which may be helpful for a broader readership outside of thermoregulation research, will build on this existing knowledge to outline possible opportunities and research directions aimed at controlling body temperature. The second part, aimed at a more specialist audience, will highlight the conceptual advantages and practical limitations of novel molecular agents targeting thermosensitive Transient Receptor Potential (TRP) channels in achieving this goal. Two particularly promising members of this channel family, namely TRP melastatin 8 (TRPM8) and TRP vanilloid 1 (TRPV1), will be discussed in greater detail.

Improved cardiac and neurologic outcomes with postresuscitation infusion of cannabinoid receptor agonist WIN55, 212-2 depend on hypothermia in a rat model of cardiac arrest

OBJECTIVES

To investigate the mechanisms of improved myocardial and neurological function and survival following i.v. administration of cannabinoid receptor agonist, WIN55, 212-2 in a rat model of cardiac arrest.

DESIGN

Prospective randomized controlled experimental study.

SETTING

University-affiliated research institute.

SUBJECTS

Thirty male Sprague-Dawley rats.

INTERVENTIONS

Ventricular fibrillation was electrically induced in 30 male Sprague-Dawley rats weighing between 450 and 550 g. Cardiopulmonary resuscitation was initiated after 6 minutes of untreated ventricular fibrillation. The precordial compression was performed with a pneumatically driven mechanical chest compressor. No pharmacological agent was used during cardiopulmonary resuscitation. After 8 minutes of cardiopulmonary resuscitation, up to three 2-J defibrillations were attempted. The animals were then randomized into three groups: 1) WIN55, 212-2 hypothermia, 2) WIN55, 212-2 with normal body temperature, and 3) placebo control. Either WIN55, 212-2 (1.0 mg/kg/hr) or saline placebo was continuously infused for 2 hours. Except for the WIN55, 212-2 hypothermia group, the body temperature in the other two groups was maintained at 37.0 ± 0.2°C using an external heating lamp. Postresuscitation myocardial function was measured by echocardiogram. Neurological deficit scores and survival time were observed for up to 72 hours.

MEASUREMENTS AND MAIN RESULTS

Blood temperatures decreased from 37°C to 33°C in 4 hours in animals in WIN55, 212-2 hypothermia group. Myocardial function, as measured by cardiac output, ejection fraction, and myocardial performance index, was significantly impaired in all animals after successful resuscitation when compared with the baseline values. There was a significant improvement in myocardial function in the animals treated with WIN55, 212-2 hypothermia beginning at 1 hour after start of infusion. However, no improvement was observed in the groups of WIN55, 212-2 with normal body temperature and placebo control. WIN55, 212-2 hypothermia group was associated with significantly improved neurologic deficit scores and survival time when compared with placebo control group and WIN55, 212-2 with normal body temperature group.

CONCLUSIONS

In a rat model of cardiac arrest, better postresuscitation myocardial function, neurological deficit scores, and longer duration of survival were observed by the pharmacologically induced hypothermia with WIN55, 212-2. The improved outcomes of cardiopulmonary resuscitation following administration of WIN55, 212-2 appeared to be the results from its temperature reduction effects.

Premedication with oral tramadol reduces severity of postoperative shivering after general anesthesia

Background:

Postanesthetic shivering (PAS) is an accompanying part of general anesthesia with different unpleasant and stressful complications. Considering the importance of proper prevention of PAS in order to reduce its related adverse complications in patients undergoing surgery, in this study, we investigated the effect of orally administrated tramadol in the prevention of this common complication of general anesthesia.

Materials and Methods:

In this prospective randomized double-blind clinical trial, 80 ASA I and II patients aged 15-70 years, scheduled for elective surgery under general anesthesia, were randomized to intervention (oral tramadol 50 mg) and placebo groups. PAS was evaluated during surgery and in the recovery room, and compared in the two study groups.

Results:

PAS was seen in 5 patients (12.5%) in the intervention group and 10 patients (25%) in the placebo group (P = 0.12). The prevalence of grade III and IV shivering was 7.5% (3/40) and 25% (10/40) in tramadol and placebo groups, respectively (P = 0.03).

Conclusion:

The overall prevalence of PAS was not significantly different in the two study groups, but the higher grades of shivering which needed treatment were significantly lower in the tramadol group than in the placebo, and those patients who received tramadol experienced milder form of shivering. It is suggested that higher doses of tramadol would have better anti-shivering as well as analgesic effects. Studying different doses of tramadol would be helpful in this regard.

[Therapeutic hypothermia and management of sudden death]

Due to its protective effects on the brain and potentially the myocardium, cooling therapy is clearly part of the standard of care of any sudden death especially in the setting of myocardial infarction. Recent guidelines recommend cooling therapy (32 to 34 °C) for 12 to 24 hours in unconscious patients with spontaneous circulation after resuscitated sudden death. We provide here a review of clinical evidence, cooling techniques and potential adverse effects of cooling therapy.

Optimal management of shivering during therapeutic hypothermia after cardiac arrest

Both pharmacological and nonpharmacological methods are used to control shivering in therapeutic hypothermia. An evidence-based protocol based on the most current research has been developed for the management of shivering during therapeutic hypothermia. Meperidine is the drug of choice and provides the greatest reduction in the shivering threshold. Other effective pharmacological agents recommended for reducing the threshold include dexmedetomidine, midazolam, fentanyl, and magnesium sulfate. In addition, skin counterwarming techniques, such as use of an air-circulating blanket, are effective nonpharmacological methods for reducing shivering when used in conjunction with medication. As a last resort, neuromuscular blocking agents are considered appropriate therapy for management of refractory shivering.

Shivering management during therapeutic temperature modulation: nurses' perspective

Therapeutic temperature modulation, which incorporates mild hypothermia and maintenance of normothermia, is being used to manage patients resuscitated after cardiac arrest. Methods of modulating temperature include intravenous infusion of cold fluids and surface or endovascular cooling. During this therapy, the shiver response is activated as a defense mechanism in response to an altered set-point temperature and causes metabolic and hemodynamic stress for patients. Recognition of shivering according to objective and subjective assessments is vital for early detection of the condition. Once shivering is detected, treatment is imperative to avoid deleterious effects. The Bedside Shivering Assessment Scale can be used to determine the efficacy of interventions intended to blunt thermoregulatory defenses and can provide continual evaluation of patients' responses to the interventions. Nurses' knowledge and understanding of the harmful effects of shivering are important to effect care and prevent injury associated with uncontrolled shivering.

Pharmacologic options for reducing the shivering response to therapeutic hypothermia

Recent literature has demonstrated significant improvements in neurologic outcomes in patients who have received induced hypothermia in the setting of out-of-hospital cardiac arrest. Through multiple metabolic mechanisms, the induction of hypothermia slows the progression and devastation of transient cerebral hypoxia. Despite these benefits, the desired reduction in core temperature is often a challenging venture as the body attempts to maintain homeostasis through the induction of thermoregulatory processes aimed at elevating body temperature. Shivering is an involuntary muscular activity that enhances heat production in an attempt to restore homeostasis. For successful induction and maintenance of induced hypothermia, shivering, as well as other thermoregulatory responses, must be overcome. Several pharmacologic options are available, either used alone or in combination, that safely and effectively prevent or treat shivering after the induction of hypothermia. We conducted a PubMed search (1966-March 2009) to identify all human investigations published in English that discussed pharmacologic mechanisms for the control of shivering. Among these options, clonidine, dexmedetomidine, and meperidine have demonstrated the greatest and most clinically relevant impact on depression of the shivering threshold. More research in this area is needed, however, and the role of the clinical pharmacist in the development and implementation of this therapy needs to be defined.

Temperature management in acute neurologic injury: to cool or not to cool

Therapeutic hypothermia is becoming an important intervention following acute neurologic injury despite inconclusive results concerning efficacy. This enthusiasm primarily stems from a lack of other effective interventions in this population. With the increase in the use of therapeutic hypothermia, several practical issues must be considered when initiating this intervention. Clinical pharmacists can play an important role in anticipating and addressing some complications such as shivering, slow drug metabolism, and infection. This review will discuss the available literature concerning the efficacy of therapeutic hypothermia in various neurologic injuries, as well as the most common adverse events associated with it.

Association of the Bedside Shivering Assessment Scale and derived EMG power during therapeutic hypothermia in survivors of cardiac arrest

INTRODUCTION

Shivering during therapeutic hypothermia (TH) after cardiac arrest (CA) is common, but the optimal means of detection and appropriate threshold for treatment are not established. In an effort to develop a quantitative, continuous tool to measure shivering, we hypothesized that continuous derived electromyography (dEMG) power detected by the Aspect A2000 or VISTA monitor would correlate with the intermittent Bedside Shivering Assessment Scale (BSAS) performed by nurses.

METHODS

Among 38 patients treated with TH after CA, 853 hourly BSAS measurements were compared to dEMG power measured every minute by a frontal surface electrode. Patients received intermittent vecuronium by protocol to treat clinically recognized shivering (BSAS>0). Mean dEMG power in decibels (dB) was determined for the hour preceding each BSAS measurement. dEMG and BSAS were compared using ANOVA.

RESULTS

The median dEMG power for a BSAS score of 0 (no shivering) was 27 dB (IQR 26-31 dB), BSAS 1 was 30.5 dB (IQR 28-35 dB), BSAS 2 was 34 dB (IQR 30-38 dB), and BSAS 3 was 34.5 dB (IQR 32-44.25). The dEMG for BSAS≥1 (shivering) was statistically different from BSAS 0 (p<0.0001). dEMG and BSAS correlated moderately (r=0.66, p<0.001).

CONCLUSION

dEMG power measured from the forehead with the Aspect A2000 or VISTA monitor during therapeutic hypothermia correlated with the Bedside Shivering Assessment Scale. Given its continuous trending of dEMG power, the A2000 or VISTA may be a useful research and clinical tool for objectively monitoring shivering.

[Managing the post-cardiac arrest syndrome. Directing Committee of the National Cardiopulmonary Resuscitation Plan (PNRCP) of the Spanish Society for Intensive Medicine, Critical Care and Coronary Units (SEMICYUC)]

Since the advent of cardiopulmonary resuscitation more than 40 years ago, we have achieved a return to spontaneous circulation in a growing proportion of patients with cardiac arrest. Nevertheless, most of these patients die in the first few days after admission to the intensive care unit (ICU), and this situation has not improved over the years. Mortality in these patients is mainly associated to brain damage. Perhaps recognizing that cardiopulmonary resuscitation does not end with the return of spontaneous circulation but rather with the return of normal brain function and total stabilization of the patient would help improve the therapeutic management of these patients in the ICU. In this sense, the term cardiocerebral resuscitation proposed by some authors might be more appropriate. The International Liaison Committee on Resuscitation recently published a consensus document on the "Post-Cardiac Arrest Syndrome" and diverse authors have proposed that post-arrest care be integrated as the fifth link in the survival chain, after early warning, early cardiopulmonary resuscitation by witnesses, early defibrillation, and early advanced life support. The therapeutic management of patients that recover spontaneous circulation after cardiopulmonary resuscitation maneuvers based on life support measures and a series of improvised actions based on "clinical judgment" might not be the best way to treat patients with post-cardiac arrest syndrome. Recent studies indicate that using goal-guided protocols to manage these patients including therapeutic measures of proven efficacy, such as inducing mild therapeutic hypothermia and early revascularization, when indicated, can improve the prognosis considerably in these patients. Given that there is no current protocol based on universally accepted evidence, the Steering Committee of the National Cardiopulmonary Resuscitation Plan of the Spanish Society of Intensive Medicine and Cardiac Units has elaborated this document after a thorough review of the literature and an online discussion involving all the members of the committee and a consensus meeting with the aim of providing a platform for the development of local protocols in different ICSs in our country to fit their own means and characteristics.

Post-cardiac arrest syndrome: Epidemiology, pathophysiology, treatment, and prognostication: A scientific statement from the International Liaison Committee on Resuscitation; the American Heart Association Emergency Cardiovascular Care Committee; the Council on Cardiovascular Surgery and Anesthesia; the Council on Cardiopulmonary, Perioperative, and Critical Care; the Council on Clinical Cardiology; the Council on Stroke (Part 1)

AIM OF THE REVIEW

To review the epidemiology, pathophysiology, treatment and prognostication in relation to the post-cardiac arrest syndrome.

METHODS

Relevant articles were identified using PubMed, EMBASE and an American Heart Association EndNote master resuscitation reference library, supplemented by hand searches of key papers. Writing groups comprising international experts were assigned to each section. Drafts of the document were circulated to all authors for comment and amendment.

RESULTS

The 4 key components of post-cardiac arrest syndrome were identified as (1) post-cardiac arrest brain injury, (2) post-cardiac arrest myocardial dysfunction, (3) systemic ischaemia/reperfusion response, and (4) persistent precipitating pathology.

CONCLUSIONS

A growing body of knowledge suggests that the individual components of the postcardiac arrest syndrome are potentially treatable.

Hypothermia after acute ischemic stroke

Induced hypothermia after ischemic stroke is a promising neuroprotective therapy and is the most potent in pre-clinical models. Technological limitations and homeostatic mechanisms that maintain core body temperature, however, have limited the clinical application of hypothermia. Advances in intravascular cooling and successful trials of hypothermia after global cerebral ischemia, such as in cardiac arrest and neonatal asphyxia, have renewed interest in hypothermia for stroke.

Hypothermia for spinal cord injury

BACKGROUND CONTEXT

Interest in systemic and local hypothermia extends back over many decades, and both have been investigated as potential neuroprotective interventions in a number of clinical settings, including traumatic brain injury, stroke, cardiac arrest, and both intracranial and thoracoabdominal aortic aneurysm surgery. The recent use of systemic hypothermia in an injured National Football League football player has focused a great deal of attention on the potential use of hypothermia in acute spinal cord injury.

PURPOSE

To provide spinal clinicians with an overview of the biological rationale for using hypothermia, the past studies and current clinical applications of hypothermia, and the basic science studies and clinical reports of the use of hypothermia in acute traumatic spinal cord injury.

STUDY DESIGN/SETTING

A review of the English literature on hypothermia was performed, starting with the original clinical description of the use of systemic hypothermia in 1940. Pertinent basic science and clinical articles were identified using PubMed and the bibliographies of the articles.

METHODS

Each article was reviewed to provide a concise description of hypothermia's biological rationale, current clinical applications, complications, and experience as a neuroprotective intervention in spinal cord injury.

RESULTS

Hypothermia has a multitude of physiologic effects. From a neuroprotective standpoint, hypothermia slows basic enzymatic activity, reduces the cell's energy requirements, and thus maintains Adenosine Triphosphate (ATP) concentrations. As such, systemic hypothermia has been shown to be neuroprotective in patients after cardiac arrest, although its benefit in other clinical settings such as traumatic brain injury, stroke, and intracranial aneurysm surgery has not been demonstrated. Animal studies of local and systemic hypothermia in traumatic spinal cord injury models have produced mixed results. Local hypothermia was actively studied in the 1970s in human acute traumatic spinal cord injury, but no case series of this intervention has been published since 1984. No peer-reviewed clinical literature could be found, which describes the application of systemic hypothermia in acute traumatic spinal cord injury.

CONCLUSIONS

Animal studies of acute traumatic spinal cord injury have not revealed a consistent neuroprotective benefit to either systemic or local hypothermia. Human studies of local hypothermia after acute traumatic spinal cord injury have not been published for over two decades. No peer-reviewed studies describing the use of systemic hypothermia in this setting could be found. Although a cogent biological rationale may exist for the use of local or systemic hypothermia in acute traumatic spinal cord injury, there is little scientific literature currently available to substantiate the clinical use of either in human patients.

Post-cardiac arrest syndrome: epidemiology, pathophysiology, treatment, and prognostication. A Scientific Statement from the International Liaison Committee on Resuscitation; the American Heart Association Emergency Cardiovascular Care Committee; the Council on Cardiovascular Surgery and Anesthesia; the Council on Cardiopulmonary, Perioperative, and Critical Care; the Council on Clinical Cardiology; the Council on Stroke

AIM OF THE REVIEW

To review the epidemiology, pathophysiology, treatment and prognostication in relation to the post-cardiac arrest syndrome.

METHODS

Relevant articles were identified using PubMed, EMBASE and an American Heart Association EndNote master resuscitation reference library, supplemented by hand searches of key papers. Writing groups comprising international experts were assigned to each section. Drafts of the document were circulated to all authors for comment and amendment.

RESULTS

The 4 key components of post-cardiac arrest syndrome were identified as (1) post-cardiac arrest brain injury, (2) post-cardiac arrest myocardial dysfunction, (3) systemic ischaemia/reperfusion response, and (4) persistent precipitating pathology.

CONCLUSIONS

A growing body of knowledge suggests that the individual components of the post-cardiac arrest syndrome are potentially treatable.