Temperature Control After In-Hospital Cardiac Arrest: A Randomized Clinical Trial

BACKGROUND

This study was conducted to determine the effect of hypothermic temperature control after in-hospital cardiac arrest (IHCA) on mortality and functional outcome as compared with normothermia.

METHODS

An investigator initiated, open-label, blinded-outcome-assessor, multicenter, randomized controlled trial comparing hypothermic temperature control (32-34°C) for 24 h with normothermia after IHCA in 11 hospitals in Germany. The primary endpoint was all-cause mortality after 180 days. Secondary end points included in-hospital mortality and favorable functional outcome using the Cerebral Performance Category scale after 180 days. A Cerebral Performance Category score of 1 or 2 was defined as a favorable functional outcome.

RESULTS

A total of 1055 patients were screened for eligibility and 249 patients were randomized: 126 were assigned to hypothermic temperature control and 123 to normothermia. The mean age of the cohort was 72.6±10.4 years, 64% (152 of 236) were male, 73% (166 of 227) of cardiac arrests were witnessed, 25% (57 of 231) had an initial shockable rhythm, and time to return of spontaneous circulation was 16.4±10.5 minutes. Target temperature was reached within 4.2±2.8 hours after randomization in the hypothermic group and temperature was controlled for 48 hours at 37.0°±0.9°C in the normothermia group. Mortality by day 180 was 72.5% (87 of 120) in hypothermic temperature control arm, compared with 71.2% (84 of 118) in the normothermia group (relative risk, 1.03 [95% CI, 0.79-1.40]; P=0.822). In-hospital mortality was 62.5% (75 of 120) in the hypothermic temperature control as compared with 57.6% (68 of 118) in the normothermia group (relative risk, 1.11 [95% CI, 0.86-1.46, P=0.443). Favorable functional outcome (Cerebral Performance Category 1 or 2) by day 180 was 22.5% (27 of 120) in the hypothermic temperature control, compared with 23.7% (28 of 118) in the normothermia group (relative risk, 1.04 [95% CI, 0.78-1.44]; P=0.822). The study was prematurely terminated because of futility.

CONCLUSIONS

Hypothermic temperature control as compared with normothermia did not improve survival nor functional outcome at day 180 in patients presenting with coma after IHCA. The HACA in-hospital trial (Hypothermia After Cardiac Arrest in-hospital) was underpowered and may have failed to detect clinically important differences between hypothermic temperature control and normothermia.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique Identifier: NCT00457431.

Hypothermic Fibrillatory Arrest During Coronary Artery Bypass Grafting in a Man With Calcified Aorta and Ventricular Fibrillation

A 67-year-old man undergoing coronary artery bypass grafting had aortic calcification that prohibited aortic cross-clamping. When ventricular fibrillation developed during surgery, we instituted hypothermic fibrillatory arrest to avoid aortic cross-clamping. In addition to our patient's case, we discuss the advantages and disadvantages of using hypothermic fibrillatory arrest during cardiac surgery.

Effect of Neotype Rectal Mild Hypothermia Therapy on Intestinal Bacterial Translocation in Rats with Hypoxic-Ischemic Brain Damage

BACKGROUND Previous studies have shown that a neotype rectal cooling device can induce mild hypothermia (MH) in Sprague-Dawley rats with ischemic-hypoxic brain damage (HIBD) and inhibit cell apoptosis in the hippocampal CAl region, and does not cause damage to rectal tissues. The present study aimed to investigate the effect of rectal MH on bacterial translocation (BT) in Sprague-Dawley rats with HIBD. MATERIAL AND METHODS A total of 60 Sprague-Dawley rats were randomly divided into 4 groups: a control group (group C), a normothermia group (group NT), a cooling blanket group (group CB), and a rectal cooling group (group RC). Rats in group CB and group RC received MH using a cooling blanket and rectal cooling device after HIBD model establishment. Then, we measured diamine oxidase (DAO) and D-lactate level separately in groups NT, CB, and RC. Finally, the spleen, liver, and mesenteric lymph nodes were collected for bacterial culture, and rectal tissues were collected for H&E staining. RESULTS The therapeutic outcome was better in Sprague-Dawley rats receiving rectal MH without rectal injury compared to rats in group CB. Escherichia coli (E. coli) was found in MLNs in group RC. E. coli, Proteus vulgaris, Stenotrophomonas maltophilia, and Acinetobacter lwoffii were detected in the rats of groups CB and NT. At 12 h following rectal MH, DAO and D-lactate levels were lower than in group NT. CONCLUSIONS The neotype rectal MH cooling method could be a potential strategy to induce rapid, controllable hypothermia, thus reducing the possibility of inflammatory cell infiltration and BT incidence.

2019 American Heart Association Focused Update on Pediatric Advanced Life Support: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

This 2019 focused update to the American Heart Association pediatric advanced life support guidelines follows the 2018 and 2019 systematic reviews performed by the Pediatric Life Support Task Force of the International Liaison Committee on Resuscitation. It aligns with the continuous evidence review process of the International Liaison Committee on Resuscitation, with updates published when the International Liaison Committee on Resuscitation completes a literature review based on new published evidence. This update provides the evidence review and treatment recommendations for advanced airway management in pediatric cardiac arrest, extracorporeal cardiopulmonary resuscitation in pediatric cardiac arrest, and pediatric targeted temperature management during post-cardiac arrest care. The writing group analyzed the systematic reviews and the original research published for each of these topics. For airway management, the writing group concluded that it is reasonable to continue bag-mask ventilation (versus attempting an advanced airway such as endotracheal intubation) in patients with out-of-hospital cardiac arrest. When extracorporeal membrane oxygenation protocols and teams are readily available, extracorporeal cardiopulmonary resuscitation should be considered for patients with cardiac diagnoses and in-hospital cardiac arrest. Finally, it is reasonable to use targeted temperature management of 32°C to 34°C followed by 36°C to 37.5°C, or to use targeted temperature management of 36°C to 37.5°C, for pediatric patients who remain comatose after resuscitation from out-of-hospital cardiac arrest or in-hospital cardiac arrest.

2019 American Heart Association Focused Update on Pediatric Advanced Life Support: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

This 2019 focused update to the American Heart Association pediatric advanced life support guidelines follows the 2018 and 2019 systematic reviews performed by the Pediatric Life Support Task Force of the International Liaison Committee on Resuscitation. It aligns with the continuous evidence review process of the International Liaison Committee on Resuscitation, with updates published when the International Liaison Committee on Resuscitation completes a literature review based on new published evidence. This update provides the evidence review and treatment recommendations for advanced airway management in pediatric cardiac arrest, extracorporeal cardiopulmonary resuscitation in pediatric cardiac arrest, and pediatric targeted temperature management during post-cardiac arrest care. The writing group analyzed the systematic reviews and the original research published for each of these topics. For airway management, the writing group concluded that it is reasonable to continue bag-mask ventilation (versus attempting an advanced airway such as endotracheal intubation) in patients with out-of-hospital cardiac arrest. When extracorporeal membrane oxygenation protocols and teams are readily available, extracorporeal cardiopulmonary resuscitation should be considered for patients with cardiac diagnoses and in-hospital cardiac arrest. Finally, it is reasonable to use targeted temperature management of 32°C to 34°C followed by 36°C to 37.5°C, or to use targeted temperature management of 36°C to 37.5°C, for pediatric patients who remain comatose after resuscitation from out-of-hospital cardiac arrest or in-hospital cardiac arrest.

The Utility of Therapeutic Hypothermia for Post-Cardiac Arrest Syndrome Patients With an Initial Nonshockable Rhythm

BACKGROUND

Therapeutic hypothermia (TH) attenuates reperfusion injury in comatose survivors of cardiac arrest. The utility of TH in patients with nonshockable initial rhythms has not been widely accepted. We sought to determine whether TH improved neurological outcome and survival in postarrest patients with nonshockable rhythms.

METHODS AND RESULTS

We identified 519 patients after in- and out-of-hospital cardiac arrest with nonshockable initial rhythms from the Penn Alliance for Therapeutic Hypothermia (PATH) registry between 2000 and 2013. Propensity score matching was used. Patient and arrest characteristics used to estimate the propensity to receive TH were age, sex, location of arrest, witnessed arrest, and duration of arrest. To determine the association between TH and outcomes, we created 2 multivariable logistic models controlling for confounders. Of 201 propensity score-matched pairs, mean age was 63 ± 17 years, 51% were male, and 60% had an initial rhythm of pulseless electric activity. Survival to hospital discharge was greater in patients who received TH (17.6% versus 28.9%; P < 0.01), as was a discharge Cerebral Performance Category of 1 to 2 (13.7% versus 21.4%; P = 0.04). In adjusted analyses, patients who received TH were more likely to survive (odds ratio, 2.8; 95% confidence interval, 1.6-4.7) and to have better neurological outcome (odds ratio, 3.5; 95% confidence interval, 1.8-6.6) than those that did not receive TH.

CONCLUSIONS

Using propensity score matching, we found that patients with nonshockable initial rhythms treated with TH had better survival and neurological outcome at hospital discharge than those who did not receive TH. Our findings further support the use of TH in patients with initial nonshockable arrest rhythms.

Continuous Amplitude-Integrated Electroencephalographic Monitoring Is a Useful Prognostic Tool for Hypothermia-Treated Cardiac Arrest Patients

Supplemental Digital Content is available in the text.

Modern treatments have improved the survival rate following cardiac arrest, but prognostication remains a challenge. We examined the prognostic value of continuous electroencephalography according to time by performing amplitude-integrated electroencephalography on patients with cardiac arrest receiving therapeutic hypothermia.

Successful Use of Therapeutic Hypothermia in a Pregnant Patient

Out-of-hospital cardiac arrest is a leading cause of death in the United States. Pregnant women are not immune to cardiac arrest, and the treatment of such patients can be difficult. Pregnancy is a relative contraindication to the use of therapeutic hypothermia after cardiac arrest. A 20-year-old woman who was 18 weeks pregnant had an out-of-hospital cardiac arrest. Upon her arrival at the emergency department, she was resuscitated and her circulation returned spontaneously, but her score on the Glasgow Coma Scale was 3. After adequate family discussion of the risks and benefits of therapeutic hypothermia, a decision was made to initiate therapeutic hypothermia per established protocol for 24 hours. The patient was successfully cooled and rewarmed. By the time she was discharged, she had experienced complete neurologic recovery, apart from some short-term memory loss. Subsequently, at 40 weeks, she delivered vaginally a 7-lb 3-oz girl whose Apgar scores were 8 and 9, at 1 and 5 minutes respectively. To our knowledge, this is only the 3rd reported case of a successful outcome following the initiation of therapeutic hypothermia for out-of-hospital cardiac arrest in a pregnant woman. On the basis of this and previous reports of successful outcomes, we recommend that therapeutic hypothermia be considered an option in the management of out-of-hospital cardiac arrest in the pregnant population. To facilitate a successful outcome, a multidisciplinary approach involving cardiology, emergency medicine, obstetrics, and neurology should be used.

Concomitant reconstruction of arch vessels during repair of aortic dissection

Surgery for acute aortic dissection is challenging, especially in cases of cerebral malperfusion. Should we perform only the aortic repair, or should we also reconstruct the arch vessels when they are severely affected by the disease process? Here we present a case of acute aortic dissection with multiple tears that involved the brachiocephalic artery and caused cerebral and right upper-extremity malperfusion. The patient successfully underwent complete replacement of the brachiocephalic artery and the aortic arch during deep hypothermic circulatory arrest, with antegrade cerebral protection. We have found this technique to be safe and reproducible for use in this group of patients.

Hypothermia improves oral and gastric mucosal oxygenation during hypoxic challenges

BACKGROUND

Therapeutic hypothermia, used primarily for protective effects after hypoxia, improves oral and gastric mucosal microvascular oxygenation (μHbO₂) during additional haemorrhage. Therefore, we questioned whether hypothermia likewise improves μHbO₂ during hypoxic challenges. Since both hypothermia and hypoxia reduce cardiac output (e.g. by myofilament Ca(2+) desensitization), and modulate vasomotor tone via K(+) ATP channels, we hypothesized that the Ca(2+) sensitizer levosimendan and K(+) ATP channel blocker glibenclamide would support the cardiovascular system.

METHODS

The effects of mild hypothermia (34°C) on μHbO₂ during hypoxia [Formula: see text] were analysed in a cross-over study on five anaesthetized dogs and compared with normothermia (37.5°C) and hypoxia. During hypothermia, but before hypoxia, glibenclamide (0.2 mg kg(-1)) or levosimendan (20 µg kg(-1)+0.25 µg kg(-1) min(-1)) was administered. Systemic haemodynamic variables, gastric and oral mucosal microvascular oxygenation (reflectance spectrophotometry), and perfusion (laser Doppler flowmetry) were recorded continuously. Data are presented as mean (sem), P<0.05.

RESULTS

Hypoxia during normothermia reduced gastric μHbO₂ by 27 (3)% and oral μHbO₂ by 28 (3)% (absolute change). During hypothermia, this reduction was attenuated to 16 (3)% and 13 (1)% (absolute change). This effect was independent of microvascular flow that did not change during hypoxia and hypothermia. Additional administration of levosimendan during hypothermia restored reduced cardiac output but did not change flow or μHbO₂ compared with hypothermia alone. Glibenclamide did not exert any additional effects during hypothermia.

CONCLUSIONS

Hypothermia attenuates the decrease in μHbO₂ during additional hypoxic challenges independent of systemic or regional flow changes. A reduction in cardiac output during hypothermia is prevented by Ca(2+) sensitization with levosimendan but not by K(+) ATP channel blockade with glibenclamide.

Seizures and magnetic resonance imaging-detected brain injury in newborns cooled for hypoxic-ischemic encephalopathy

OBJECTIVE

To describe the association between electrographically detected seizures and brain injury evaluated by magnetic resonance imaging in newborns treated with hypothermia.

STUDY DESIGN

A total of 56 newborns treated with hypothermia were monitored using video electroencephalography through cooling and rewarming, and then imaged at a median of 5 days. The electroencephalograms were reviewed for indications of seizure and status epilepticus. Moderate-severe injury detected on magnetic resonance imaging was measured using a classification scheme similar to one predicting abnormal outcome in an analogous population.

RESULTS

Seizures were recorded in 17 newborns (30%), 5 with status epilepticus. Moderate-severe injury was more common in newborns with seizures (relative risk, 2.9; 95% CI, 1.2-4.5; P=.02), and was present in all 5 newborns with status epilepticus. Newborns with moderate-severe injury had seizures that were multifocal and of later onset, and they were more likely to experience recurrent seizures after treatment with 20 mg/kg phenobarbital. Newborns with only subclinical seizures were as likely to have injury as those with seizures with a clinical correlate (57% vs 60%).

CONCLUSION

Seizures represent a risk factor for brain injury in the setting of therapeutic hypothermia, especially in neonates with status epilepticus, multifocal-onset seizures, and a need for multiple medications. However, 40% of our neonates were spared from brain injury, suggesting that the outcome after seizures is not uniformly poor in children treated with therapeutic hypothermia.

Therapeutic hypothermia is associated with a decrease in urine output in acute stroke patients

AIMS

It is unclear what effect therapeutic hypothermia may have on renal function, because its effect has so far been primarily evaluated in settings in which there may be possible confounding perturbations in cardiovascular and renal physiology, such deep intraoperative hypothermia, general anesthesia, and post-cardiac arrest. We sought to determine if therapeutic hypothermia affects renal function in awake patients with normal renal function who were enrolled into a clinical trial of hypothermia plus intravenous thrombolysis for acute ischemic stroke.

METHODS

Eleven patients with normal renal function were cooled to 33°C for 24 h using an endovascular catheter, and then re-warmed over 12 h to 36.5°C, while hourly temperature, blood pressure, and fluid status data was recorded. Blood samples for blood urea nitrogen (BUN), creatinine, and hematocrit were drawn prior to treatment (baseline), immediately after hypothermia and re-warming (day 2), and again at day 7 or discharge, and values compared.

RESULTS

On initiation of cooling, temperatures dropped from a median pre-treatment value of 36.1°C (IQR: 35.8-36.4°C) to 33.1°C (IQR: 33.1-33.4°C). Urine output decreased 5.1 ml/h for every 1°C decrease in body temperature (p-value=0.001), with no associated serious adverse events. There were no statistically significant changes in BUN, creatinine, or hematocrit in the hypothermia patients.

CONCLUSION

Inducing hypothermia in patients with relatively unperturbed renal physiology results in a decrease in urine output that is linearly correlated with the decrease in core temperature. This has important implications for fluid management in patients undergoing therapeutic hypothermia.

Volumetric and anatomical MRI for hypoxic-ischemic encephalopathy: relationship to hypothermia therapy and neurosensory impairments

OBJECTIVE

To relate volumetric magnetic resonance imaging (MRI) findings to hypothermia therapy and neurosensory impairments.

STUDY DESIGN

Newborns > or =36 weeks' gestation with hypoxic-ischemic encephalopathy who participated in the National Institute of Child Health and Human Development hypothermia randomized trial at our center were eligible. We determined the relationship between hypothermia treatment and usual care (control) to absolute and relative cerebral tissue volumes. Furthermore, we correlated brain volumes with death or neurosensory impairments at 18 to 22 months.

RESULT

Both treatment groups were comparable before randomization. Total brain tissue volumes did not differ in relation to treatment assignment. However, relative volumes of subcortical white matter were significantly larger in hypothermia-treated than control infants. Furthermore, relative total brain volumes correlated significantly with death or neurosensory impairments. Relative volumes of the cortical gray and subcortical white matter also correlated significantly with Bayley Scales psychomotor development index.

CONCLUSION

Selected volumetric MRI findings correlated with hypothermia therapy and neurosensory impairments. Larger studies using MRI brain volumes as a secondary outcome measure are needed.

Translocation of prosthetic aortic valve in advanced prosthetic valve endocarditis

Advanced prosthetic valve endocarditis is often associated with substantial destruction of the tissues adjacent to the prosthesis. Removal of the infected prosthesis and débridement of the infected tissues make implantation of a new prosthesis challenging. Herein, we discuss successful surgical aortic valve translocation in a 50-year-old man who had advanced acute prosthetic valve endocarditis with destruction of the aortic annulus. One year after being discharged from the hospital, the patient was asymptomatic with good exercise tolerance.

Management of air embolism during HeartMate XVE exchange

Air embolism is a rare and usually fatal complication of major cardiac surgery. We present a case in which a 45-year-old man supported by a HeartMate(R) XVE left ventricular assist device required a pump exchange due to failure of the device motor. During pump dissection, a massive amount of air entered the systemic circulation. Urgent cannulation for cardiopulmonary bypass was performed, and cardiopulmonary bypass was initiated, followed by profound hypothermia, circulatory arrest, retrograde cerebral perfusion, retrograde coronary sinus perfusion, and then barbiturate coma and steroid therapy. The HeartMate XVE left ventricular assist device was removed, and a HeartMate II was implanted. After 5 days, the patient awoke with left hemiparesis, which nearly resolved with aggressive physical therapy. Forty-four days after the pump exchange operation, the patient was discharged from the hospital with only mild left hemiparesis. Exposure of the left ventricular assist device or its external components requires careful monitoring, because air can enter the pump-particularly in a hypovolemic patient. Rapid response after massive air entry into the left ventricular assist device system, as in our patient, can result in a successful outcome.

Clinical outcomes in "complex" thoracic aortic surgery

Although the term "complex aortic surgery" has come into increasing use, it has not been defined. We propose the following definition: replacement or remodeling (not resuspension of commissures) of the aortic root, together with either an intracardiac procedure or a replacement of more than 1 segment of aorta, all of which require cerebral protection. We retrospectively analyzed data pertaining to 152 patients (mean age, 56 +/- 12 years) who underwent surgery for thoracic aortic disease with aid of cardiopulmonary bypass from October 2000 through December 2005. The replaced segment was the ascending aorta with or without the root in 106 patients, the aortic arch in 15, and the descending aorta in 31. Among these patients, 10 met our proposed criteria and constituted the complex group. In this group, in addition to the aortic root, the entire thoracic aorta (ascending, arch, and descending) was replaced in 4 patients, the total arch in 2, and a partial arch in 1. The remaining 3 underwent valve or coarctation repair. Their outcomes were analyzed as a sub-group within the overall outcome. The in-hospital mortality rate was 12.5% in the overall group (19/152), 4.1% in elective cases (3/73), and 10% in the complex group (1/10). Duration of cardiopulmonary bypass, myocardial ischemia, and total cerebral protection times were significantly longer in the complex group (P <0.0001). Total cerebral protection time over 40 minutes was the only predictor of neurologic morbidity (P = 0.003; odds ratio, 4.7). Procedural complexity, as we defined it, increased neurologic morbidity, but not the mortality rate.

Directed retrograde cerebral protection during moderate hypothermic circulatory arrest

There are many choices for neurologic protection for aortic arch surgery. Although numerous investigators have challenged the efficacy of retrograde cerebral perfusion, we have had good results with our application of this technique. We performed a retrospective review of 8 consecutive patients who underwent surgery from 1 June 2001 through 31 March 2003; the age range was 33 to 97 years. All patients required circulatory arrest and underwent retrograde cerebral perfusion with use of a tourniquet on the patients' left and right arms above the elbow to direct retrograde flow to the brain. Moderate hypothermia (around 24 degrees C nasopharyngeal) was used; circulatory arrest time ranged from 27 to 63 minutes. There was 1 late hospital death due to multiple-organ system failure. There were no neurologic complications (stroke or temporary neurologic dysfunction). There was no substantive neurologic or renal dysfunction in this cohort, in which moderate hypothermia was used. These results are comparable to those reported in the literature for similar patients. We conclude that, for patients who require circulatory arrest, directed retrograde cerebral perfusion at moderate nasopharyngeal hypothermia gives results comparable to those reported with other techniques.

Cerebral perfusion through separate grafts for repair of acute aortic dissection with torn arch

We have modified the technique of cerebral perfusion through anastomosed grafts for repair of acute arch dissections that require total arch replacement. We have performed this operation on a 71-year-old man with an acute type-A dissection and an arch tear between the orifices of the brachiocephalic arteries. We used 2 separate grafts for the brachiocephalic arteries and minimized brain ischemia by initiating antegrade selective cerebral perfusion after the 1st anastomosis. The patient had an excellent outcome. This method is simple and provides effective protection. Cerebral ischemic time can be kept under 30 minutes without need of a sophisticated pump setup or a multibranched graft. This affords extra time in case the surgeon encounters an unexpected lesion in the arch.

Phrenic nerve injury during coronary artery bypass

After coronary artery bypass, some patients have diaphragmatic elevation, usually on the left side. To test our hypothesis that this phenomenon is due to phrenic nerve injury resulting from either 1) dissection of the proximal portion of the left internal mammary artery or 2) topical cooling of the heart with icy slush, we performed the following 2-part study. First, we reviewed our hospital records of 99 coronary artery bypass patients, 55 of whom had received left internal mammary artery grafts and 44 of whom had undergone saphenous vein grafting; the results showed no significant difference between the rates of left-sided diaphragmatic paralysis in the 2 groups (47% versus 41%, respectively). Next, we performed a prospective, randomized study in 100 consecutive patients, using a cardiac insulation pad to protect the left phrenic nerve in 58 patients and using no protective pad in 42 patients. At the time of hospital discharge, left-sided diaphragmatic elevation was seen in 6 (10.3%) of the 58 patients in whom insulation had been used and in 19 (45.2%) of the 42 patients whose phrenic nerve had been unprotected (p < 0.001). We conclude that cooling of the left phrenic nerve with icy slush in the pericardial cavity causes left-sided diaphragmatic paralysis and that the frequency of this injury can be reduced if a cardiac insulation pad is placed between the nerve and the icy slush.