Early and long-term results of hypothermic circulatory arrest in aortic surgery: a 20-year single-centre experience

AIMS

The aim of this study was to document the postoperative outcomes of patients who underwent hypothermic circulatory arrest (HCA), the evolution of HCA management over time and to identify the risks factor for early mortality and postoperative stroke.

METHODS

Four hundred and twenty-four patients who underwent aortic surgery with HCA at our institution between January 1995 and June 2016 were consecutively included.

RESULTS

The main indications were degenerative aneurysm (254; 59.9%) and acute type A aortic dissection (146; 34.4%). Interventions were performed under deep (18.4 ± 0.9°C; n = 350; 82.5%) or moderate (23.9 ± 1.9°C; n = 74; 17.5%) hypothermia. Antegrade cerebral perfusion (ACP) was employed in 86 (20.3%) cases. The use of moderate hypothermia significantly increased from 2011, to become the preferred strategy in 2016. The in-hospital mortality was 12.5% and the postoperative stroke rate was 7.1%. Kaplan--Meier 5-year survival was 65.7%. Nonelective timing [odds ratio (OR) 4.05; P < 0.001], stroke (OR 3.77' P = 0.032), renal failure (OR 2.49; P = 0.023), redo surgery (2.42; P = 0.049) and CPB time (OR 1.05; P = 0.03) were independent risk factors for in-hospital mortality in multivariate analysis. Femoral cannulation was the only independent risk factor for stroke (OR 3.97; P = 0.002). The level of hypothermia and the use of ACP were not associated with either in-hospital mortality or postoperative stroke.

CONCLUSION

HCA might be widely considered to achieve a radical treatment of the aortic disease, provided that hypothermia is maintained below the 24°C safety threshold and ACP is used for HCA exceeding 30 min, to ensure optimal brain, spinal cord and visceral organs protection.

Quality improvement for reducing utilization drift in hypoxic-ischemic encephalopathy management

OBJECTIVES

Therapeutic hypothermia is an effective neuroprotective intervention for infants with moderate or severe hypoxic-ischemic encephalopathy (HIE). With the introduction of new medical therapy comes a learning curve with regards to its proper implementation and understanding of eligibility guidelines. We hypothesized that variation in patient selection and lack of adherence to established protocols contributed to the utilization drift away from the original eligibility guidelines.

METHODS

A retrospective cohort study was conducted including infants who received therapeutic hypothermia in the neonatal intensive care unit (NICU) for HIE to determine utilization drift. We then used QI methodology to address gaps in medical documentation that may lead to the conclusion that therapeutic hypothermia was inappropriately applied.

RESULTS

We identified 54% of infants who received therapeutic hypothermia who did not meet the clinical, physiologic, and neurologic examination criteria for this intervention based on provider admission and discharge documentation within the electronic medical record (EMR). Review of the charts identified incomplete documentation in 71% of cases and led to the following interventions: 1) implementation of EMR smartphrases; 2) engagement of key stakeholders and education of faculty, residents, and neonatal nurse practitioners; and 3) performance measurement and sharing of data. We were able to improve both adherence to the therapeutic hypothermia guidelines and achieve 100% documentation of the modified Sarnat score.

CONCLUSIONS

Incomplete documentation can lead to the assumption that therapeutic hypothermia was inappropriately applied when reviewing a patient's EMR. However, in actual clinical practice physicians follow the clinical guidelines but are not documenting their medical decision making completely. QI methodology addresses this gap in documentation, which will help determine the true utilization drift of therapeutic hypothermia in future studies.

Trends, Predictors and Outcomes After Utilization of Targeted Temperature Management in Cardiac Arrest Patients With Anoxic Brain Injury

BACKGROUND

Targeted Temperature Management (TTM) is a class I recommendation for the management of sudden cardiac arrest (SCA) patients with presumed brain injury. We aimed to study trends, predictors and outcomes in SCA patients from a nationally represented US population sample.

METHODS

We utilized the National Inpatient Sample from years 2005 to 2014 for the purpose of our study. Patients with SCA and anoxic brain injury were selected using relevant ICD-9 codes. Data were analyzed for trends over the years and key outcomes were assessed. Logistic regression analysis was done to determine predictors of TTM utilization in our study population.

RESULTS

A total of 78,465 patients with SCA and anoxic brain injury were identified from January 2005 to December 2014. Out of these, approximately 4,481 (5.7%) patients underwent TTM. Patients that underwent TTM were younger compared to patients without TTM utilization (60.67 vs. 63.27 years, P < 0.01). African Americans, Hispanics and women were less likely to undergo TTM. Myocardial infarction, electrolyte disorders and cardiogenic shock were associated with higher odds of TTM utilization. Sepsis, renal failure and diabetes were associated with underutilization of TTM. Inpatient mortality was higher in patients who did not undergo TTM when compared to patients who underwent TTM (67.30% vs. 65.10%, P < 0.01).

CONCLUSIONS

Although TTM utilization increased over our study period, the overall application of TTM was still dismal. Factors that circumvent TTM utilization need to be addressed in future studies so more eligible patients could benefit from this life saving therapy.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Predictive performance of plasma neutrophil gelatinase-associated lipocalin for neurologic outcomes in out-of-hospital cardiac arrest patients treated with targeted temperature management: A prospective observational study

Few studies have demonstrated the prognostic potential of neutrophil gelatinase-associated lipocalin (NGAL) in post-cardiac arrest patients. This study evaluated the usefulness of plasma NGAL in predicting neurologic outcome and mortality in out-of-hospital cardiac arrest (OHCA) patients treated with targeted temperature management (TTM). A prospective observational study was conducted between October 2013 and April 2016 at a single tertiary hospital. We enrolled 75 patients treated with TTM and collected their demographic data, cardiopulmonary resuscitation-related information, data on plasma NGAL concentration, and prognostic test results. Plasma NGAL was measured at 4 hours after return of spontaneous circulation (ROSC). The primary endpoint was the neurologic outcome at discharge and the secondary outcome was 28-day mortality. Neurologic outcomes were analyzed using a stepwise multivariate logistic regression while 28-day mortality was analyzed using a stepwise Cox regression. The predictive performance of plasma NGAL for neurologic outcome was measured by the area under the receiver operating characteristic curve and the predictability of 28-day mortality was measured using Harrell C-index. We also compared the predictive performance of plasma NGAL to that of other traditional prognostic modalities for outcome variables. Thirty patients (40%) had good neurologic outcomes and 53 (70.7%) survived for more than 28 days. Plasma NGAL in patients with good neurologic outcomes was 122.7 ± 146.7 ng/ml, which was significantly lower than that in the poor neurologic outcome group (307.5 ± 269.6 ng/ml; P < .001). The probability of a poor neurologic outcome was more than 3.3-fold in the NGAL >124.3 ng/ml group (odds ratio, 3.321; 95% confidence interval [CI], 1.265-8.721]). Plasma NGAL in the survived group was significantly lower than that in the non-survived group (172.7 ± 191.6 vs 379.9 ± 297.8 ng/ml; P = .005). Plasma NGAL was significantly correlated with 28-day mortality (hazard ratio 1.003, 95% CI 1.001-1.004; P < .001). The predictive performance of plasma NGAL was not inferior to that of other prognostic modalities except electroencephalography. Plasma NGAL is valuable for predicting the neurologic outcome and 28-day mortality of patients with OHCA at an early stage after ROSC.This study was registered at ClinicalTrials.gov on November 19, 2013 (Identifier: NCT01987466).

Initial arterial pH as a predictor of neurologic outcome after out-of-hospital cardiac arrest: A propensity-adjusted analysis

BACKGROUND

Lower pH after out-of-hospital cardiac arrest (OHCA) has been associated with worsening neurologic outcome, with <7.2 identified as an "unfavorable resuscitation feature" in consensus treatment algorithms despite conflicting data. This study aimed to describe the relationship between decremental post-resuscitation pH and neurologic outcomes after OHCA.

METHODS

Consecutive OHCA patients treated with targeted temperature management (TTM) at multiple US centers from 2008 to 2017 were evaluated. Poor neurologic outcome at hospital discharge was defined as cerebral performance category ≥3. The exposure was initial arterial pH after return of spontaneous circulation (ROSC) analyzed in decremental 0.05 thresholds. Potential confounders (demographics, history, resuscitation characteristics, initial studies) were defined a priori and controlled for via ATT-weighting on the inverse propensity score plus direct adjustment for the linear propensity score.

RESULTS

Of 723 patients, 589 (80%) experienced poor neurologic outcome at hospital discharge. After propensity-adjustment with excellent covariate balance, the adjusted odds ratios for poor neurologic outcome by pH threshold were: ≤7.3: 2.0 (1.0-4.0); ≤7.25: 1.9 (1.2-3.1); ≤7.2: 2.1 (1.3-3.3); ≤7.15: 1.9 (1.2-3.1); ≤7.1: 2.4 (1.4-4.1); ≤7.05: 3.1 (1.5-6.3); ≤7.0: 4.5 (1.8-12).

CONCLUSIONS

No increased hazard of progressively poor neurologic outcomes was observed in resuscitated OHCA patients treated with TTM until the initial post-ROSC arterial pH was at least ≤7.1. This threshold is more acidic than in current guidelines, suggesting the possibility that post-arrest pH may be utilized presently as an inappropriately-pessimistic prognosticator.

Efficacy and safety of cooled and uncooled microwave ablation for the treatment of benign thyroid nodules: a systematic review and meta-analysis

PURPOSE

To evaluate the effectiveness and safety of microwave ablation (MWA), including cooled MWA (cMWA) and uncooled MWA (uMWA), for the treatment of benign thyroid nodules (BTNs).

METHODS

The databases of MEDLINE, EMBASE and Cochrane library were searched up to 3 Jun, 2018. In this meta-analysis, data of volume reduction rates (VRRs) at the 3-, 6- and 12-month follow-up, and complications are obtained to evaluate the effectiveness and safety of cMWA and uMWA for the treatment of BTNs.

RESULTS

Nine studies involving 1461 patients with 1845 BTNs were included. The pooled VRR at the 3-month follow-up after MWA therapy reached 54.3% (95% CI: 45.3-63.3%, I2 = 97.6%), 73.5% (95% CI: 66.7-80.3%, I2 = 94.9%) at the 6-month follow-up, and 88.6% (95% CI: 84.9-92.4%, I2 = 92.7%) at the 12-month follow-up. The pooled proportions of overall, major and minor complications were 52.4% (95% CI: 29.8-74.9%; I2 = 99.5%), 4.8% (95% CI: 2.7-7.0%; I2 = 55.9%) and 48.3% (95% CI: 31.2-65.4%; I2 = 99.7%). Both cMWA and uMWA achieved similar pooled VRR at the 3-month follow-up (58.4 vs 45.3%, P = 0.07) and pooled proportion of major complications (4.9 vs 5.0%, P = 0.49), while uMWA had higher pooled proportions of overall and minor complications than cMWA (97.8 vs 29.7%, P < 0.01; 97.8 vs 21.0%, P < 0.01), with more patients suffering pain and skin burn after uMWA (100 vs 5.5%, P < 0.01; 47.2 vs 0.2%, P < 0.01).

CONCLUSION

MWA is an effective treatment modality for BTNs. When considering the patient's comfort, cMWA would be a more preferable procedure with less complications.

Medico-legal implications of hypothermic neuroprotection in the newborn

Hypoxic-ischemic encephalopathy (HIE) continues to be a significant source of long term neurological sequelae in infants born at or near term. In the past decade, selective head or whole body cooling has shown promising benefit in ameliorating some of the brain injury from intrapartum asphyxial insults and has become standard care in most developed countries. A decision to offer neuroprotective hypothermia (NPH) may engender subsequent litigation because it presupposes an acute intrapartum injury. Conversely, failing to offer cooling may be interpreted as a violation in the standard of care. In this paper, we review the clinical aspects of NPH and the medico-legal scenarios often seen after acute birth injury.

Outcomes After Percutaneous Coronary Intervention of Acute Coronary Syndrome Complicated With Cardiopulmonary Arrest (from a Japanese Multicenter Registry)

Details on the characteristics and outcomes in patients with acute coronary syndrome (ACS) complicated with cardiopulmonary arrest (CPA) have been limited. We evaluated inhospital outcomes after percutaneous coronary intervention in these patients. From 2008 to 2014, 5,943 patients with ACS including 2,973 patients with ST-elevation myocardial infarction (STEMI) and 2,970 patients with non-STEMI or unstable angina (NSTE-ACS) were registered. In total, 264 patients experienced CPA within 24 hours of admission. Patients with CPA presented more frequently with cardiogenic shock (CS) (79.0% vs 7.7% in STEMI; 78.0% vs 1.1% in NSTE-ACS; p <0.001, respectively) and had a higher mortality rate (26.2% vs 3.8% in STEMI; 36.0% vs 1.6% in NSTE-ACS; p <0.001, respectively) than those without. On multivariate analysis, both age (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.02 to 1.07, p = 0.002) and presence of CS (OR 5.54, 95% CI 2.19 to 17.13, p <0.001) were independent predictors of inhospital mortality in patients with ACS complicated with CPA and adjusted ORs increased exponentially under the presence of these variables (age ≥75 years: OR 3.16, 95% CI 2.14 to 4.70; CS: OR 18.70, 95% CI 12.40 to 28.40; presence of both these factors: OR 33.80, 95% CI 21.13 to 54.23). In conclusion, the mortality rate after percutaneous coronary intervention remains high in patients with ACS complicated with CPA. Older age and shock status were strongly associated with inhospital mortality in these patients.

Association Between Therapeutic Hypothermia and Survival After In-Hospital Cardiac Arrest

IMPORTANCE

Therapeutic hypothermia is used for patients following both out-of-hospital and in-hospital cardiac arrest. However, randomized trials on its efficacy for the in-hospital setting do not exist, and comparative effectiveness data are limited.

OBJECTIVE

To evaluate the association between therapeutic hypothermia and survival after in-hospital cardiac arrest.

DESIGN, SETTING, AND PATIENTS

In this cohort study, within the national Get With the Guidelines-Resuscitation registry, 26 183 patients successfully resuscitated from an in-hospital cardiac arrest between March 1, 2002, and December 31, 2014, and either treated or not treated with hypothermia at 355 US hospitals were identified. Follow-up ended February 4, 2015.

EXPOSURE

Induction of therapeutic hypothermia.

MAIN OUTCOMES AND MEASURES

The primary outcome was survival to hospital discharge. The secondary outcome was favorable neurological survival, defined as a Cerebral Performance Category score of 1 or 2 (ie, without severe neurological disability). Comparisons were performed using a matched propensity score analysis and examined for all cardiac arrests and separately for nonshockable (asystole and pulseless electrical activity) and shockable (ventricular fibrillation and pulseless ventricular tachycardia) cardiac arrests.

RESULTS

Overall, 1568 of 26 183 patients with in-hospital cardiac arrest (6.0%) were treated with therapeutic hypothermia; 1524 of these patients (mean [SD] age, 61.6 [16.2] years; 58.5% male) were matched by propensity score to 3714 non-hypothermia-treated patients (mean [SD] age, 62.2 [17.5] years; 57.1% male). After adjustment, therapeutic hypothermia was associated with lower in-hospital survival (27.4% vs 29.2%; relative risk [RR], 0.88 [95% CI, 0.80 to 0.97]; risk difference, -3.6% [95% CI, -6.3% to -0.9%]; P = .01), and this association was similar (interaction P = .74) for nonshockable cardiac arrest rhythms (22.2% vs 24.5%; RR, 0.87 [95% CI, 0.76 to 0.99]; risk difference, -3.2% [95% CI, -6.2% to -0.3%]) and shockable cardiac arrest rhythms (41.3% vs 44.1%; RR, 0.90 [95% CI, 0.77 to 1.05]; risk difference, -4.6% [95% CI, -10.9% to 1.7%]). Therapeutic hypothermia was also associated with lower rates of favorable neurological survival for the overall cohort (hypothermia-treated group, 17.0% [246 of 1443 patients]; non-hypothermia-treated group, 20.5% [725 of 3529 patients]; RR, 0.79 [95% CI, 0.69 to 0.90]; risk difference, -4.4% [95% CI, -6.8% to -2.0%]; P < .001) and for both rhythm types (interaction P = .88).

CONCLUSIONS AND RELEVANCE

Among patients with in-hospital cardiac arrest, use of therapeutic hypothermia compared with usual care was associated with a lower likelihood of survival to hospital discharge and a lower likelihood of favorable neurological survival. These observational findings warrant a randomized clinical trial to assess efficacy of therapeutic hypothermia for in-hospital cardiac arrest.

An Assessment of Emergency Department Post-Cardiac Arrest Care Variation in Michigan

Implementation of postarrest care by individual physicians and systems has been slow. Deadoption, or discontinuation of therapeutic hypothermia (TH) treatment targets, after recent prospective study results has not been well reported. This study assesses practices in the early stages of postarrest care across emergency departments (EDs) in Michigan. A 27-question Internet-based survey was distributed to EDs in Michigan in September 2013. To assess changes in practice after publication of Nielsen et al., we sent follow-up questions to all original respondents a year later. Observational data and descriptive statistics are reported. From the 142 EDs identified, we excluded critical access hospitals (N = 35), free standing EDs (N = 7), EDs that transfer critical patients to tertiary centers (N = 21), and exclusive children's hospitals (N = 3). Of the remaining 76 hospitals, we received 64 (84.2%) responses. We identified 15 respondents with a protocol to specifically initiate ED TH and transfer patients to a higher level of care. The 49 remaining were mostly teaching institutions (N = 34, 69%) and gave the ED physician the ability to initiate TH (N = 40, 82%). On follow-up 12 months later, we received 33/40 (83%) responses, of which only 5 indicated formal or informal change in TH practice or target temperature. There is substantial variation in the practice of ED postarrest care and initiation of TH across the state of Michigan, but few ED TH protocols were changed in a year's time. The consequences of postarrest treatment variability at the state and ED levels are likely under-recognized as an influence on outcome variation between regions.

Therapeutic Hypothermia in ICUs

Recent research on Therapeutic Hypothermia (TH) post cardiac arrest has raised questions about its implementation and benefits. TH to 32-34 degrees C is still included in international guidelines for post-cardiac arrest care. We investigated how Irish ICUs are utilising TH as part of their management of patients post cardiac arrest using a telephone survey of all Irish ICUs. All 25 ICUs in Ireland participated. As of quarter 2 2014, TH was part of post-cardiac arrest management in 20 ICUs (80%), which is similar to international figures. 2011 was the median year for units to start using TH in Ireland. Over half 13 (52%) of Irish ICUs have experience with cooling more than 10 patients. Despite lack of evidence for its benefit, 12 ICUs (48%) use TH for OHCA non VF-VT arrests. Lack of resources was cited by 2 ICUs (8%) as well as no local consensus by 1 ICU (4%) prevented a small minority adopting the protocol. Similar methods of inducing and maintaining TH were found in Ireland as with overseas. Interest was expressed in recent research on TH and in 2 ICUs local practice had changed because of it. An updated international resuscitation guideline is awaited.

The baby cooling project of Japan to implement evidence-based neonatal cooling

Therapeutic hypothermia was first recommended as a standard of care by international guidelines in 2010. However, at that time, the number of centers capable of providing standard cooling was limited even in Japan. The aim of this project was to implement a nationwide network of evidence-based cooling within 3 years. A taskforce was formed in June 2010 to undergo the primary nationwide practice survey, design of action plans, and the appraisal of interventions by involving all registered level-II/III neonatal intensive care units in Japan. Based on findings from the primary survey, aggressive action plans were introduced that focused on the formulation of clinical recommendations, facilitation of educational events, and opening of an online case registry. Findings from the follow-up survey (January 2013) were compared with the results from the primary survey (June 2010). Four workshops and three consensus meetings were held to formulate clinical recommendations, which were followed by the publication of practical textbooks, large-scale education seminars, and implementation of a case registry. A follow-up survey covering 253 units (response rate: 89.1%) showed that cooling centers increased from 89 to 135. Twelve prefectures had no cooling centers in 2010, whereas all 47 prefectures had at least one in 2013. In cooling centers, adherence to the standard cooling protocols and the use of servo-controlled cooling devices improved from 20.7% to 94.7% and from 79.8% to 98.5%, respectively. A rapid improvement in the national provision of evidence-based cooling was achieved. International consensus guidelines coupled with domestic interventions might be effective in changing empirical approaches to evidence-based practice.

Therapeutic hypothermia for cardiac arrest: real-world utilization trends and hospital mortality

BACKGROUND

Therapeutic hypothermia (TH) improves outcomes following cardiac arrest in small clinical trials.

OBJECTIVE

To study real-world utilization and outcomes in US hospitals.

DESIGN

Retrospective cohort study.

SETTING

California hospitals.

PATIENTS

Patients eligible for therapeutic hypothermia after cardiac arrest.

INTERVENTIONS

We analyzed all discharges from California (1999-2008) to identify patients eligible for TH after cardiac arrest. Patients were considered eligible for TH if both cardiac arrest and anoxic brain injury were among the administrative diagnoses (n = 46,833). Patients undergoing TH (n = 204) were identified through billing codes.

MEASUREMENTS

TH utilization and in-hospital mortality.

RESULTS

Use of TH increased over the study period with 87.3% (178/204) of TH occurring between 2006 and 2008. Few hospitals appeared to perform TH over the study period (47/419, 11.2%). Utilization of TH was concentrated in a few centers, with the top 3 of 419 centers accounting for 31.4% (64/204) of cases. Patients undergoing TH were younger, less likely to be male, more likely to be treated at teaching centers, and had similar comorbidities compared to eligible individuals who did not undergo TH. The adjusted odds ratio for hospital mortality among patients undergoing TH was 0.80 (95% confidence interval [CI] 0.60-1.06, P = 0.11).

CONCLUSIONS

TH utilization appears low, but implementation is increasing. Case selection and referral biases limit the analysis of the relationship between center TH volume and in-hospital mortality.

Severity of cardiovascular disease patients transported by air ambulance

INTRODUCTION

Although helicopters have been used in an air ambulance system for the past decade in Japan, the appropriate selection of patients for this transport mode has not been investigated. The present study investigates which patients could potentially benefit the most from helicopter emergency medical service (HEMS).

METHODS

We investigated the extent of circulatory and respiratory support required in the intensive care unit (ICU) and ultimate outcomes of 2340 patients with cardiovascular disease admitted to 1 institution between October 2001 and December 2009. Two hundred and seventy were transported by HEMS (HEMS group), and 2070 were transported by other means (non-HEMS group).

RESULTS

Temporary cardiac pacing, ventilator management, intra-aortic balloon pumping, percutaneous cardiopulmonary support, electrical defibrillation, and therapeutic hypothermia were more frequently required by patients in the HEMS group vs. the non-HEMS group (10.4%, 28.1%, 17.0%, 5.2%, 10.0% and 3.4% vs. 8%, 17.9%, 10.9%, 2.3%, 4.5% and 0.4%, respectively). The mortality rate was higher in the HEMS group than in the non-HEMS group in the ICU (9.6% vs. 5.3%).

CONCLUSION

Disease was more clinically severe and the outcome was poorer among patients with cardiovascular diseases transported by HEMS than by other means.

Adolescents with d-transposition of the great arteries corrected with the arterial switch procedure: neuropsychological assessment and structural brain imaging

BACKGROUND

We report neuropsychological and structural brain imaging assessments in children 16 years of age with d-transposition of the great arteries who underwent the arterial switch operation as infants. Children were randomly assigned to a vital organ support method, deep hypothermia with either total circulatory arrest or continuous low-flow cardiopulmonary bypass.

METHODS AND RESULTS

Of 159 eligible adolescents, 139 (87%) participated. Academic achievement, memory, executive functions, visual-spatial skills, attention, and social cognition were assessed. Few significant treatment group differences were found. The occurrence of seizures in the postoperative period was the medical variable most consistently related to worse outcomes. The scores of both treatment groups tended to be lower than those of the test normative populations, with substantial proportions scoring ≥1 SDs below the expected mean. Although the test scores of most adolescents in this trial cohort are in the average range, a substantial proportion have received remedial academic or behavioral services (65%). Magnetic resonance imaging abnormalities were more frequent in the d-transposition of the great arteries group (33%) than in a referent group (4%).

CONCLUSIONS

Adolescents with d-transposition of the great arteries who have undergone the arterial switch operation are at increased neurodevelopmental risk. These data suggest that children with congenital heart disease may benefit from ongoing surveillance to identify emerging difficulties.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000470.

Implementation of therapeutic hypothermia after cardiac arrest--a telephone survey of Connecticut hospitals

RATIONALE

We hypothesize that despite excellent evidence supporting use of therapeutic hypothermia (TH) after cardiac arrest, only some of Connecticut hospitals utilize this technique for cardiac arrest patients.

METHODS

Telephone survey of all adult acute care Connecticut hospitals between January and April 2010.

RESULTS

Among 31 adult acute care hospitals, 27 care for cardiac arrest patients. Seventeen out of 27 hospitals use TH (63%) for cardiac arrest patients. No significant association was found between use of TH and hospital size (P=0.14), ICU type (P=0.07) or BC/BE critical-care physician staffing (P= 0.22). Lack of resources and cost of TH were commonly mentioned as barriers.

CONCLUSIONS

Therapeutic hypothermia is underutilized in Connecticut with almost half of all hospitals currently not employing TH. Given the slow adoption rate of TH, state-level leadership may be indicated to accelerate implementation of this life-saving technique.

Therapeutic hypothermia in Italian intensive care units: a national survey

BACKGROUND

The aim of this study was to investigate the use of therapeutic hypothermia (TH) in Italian Intensive Care Units (ICUs).

DESIGN AND SETTINGS

After being contacted by phone, a structured questionnaire to evaluate the use of TH was sent to all Italian ICUs. The questionnaire was aimed at determining the extent of TH use (indications, methods employed, target temperature, side effects) as well as the reasons why some ICUs did not make use of TH for the treatment of cardiac arrest patients.

RESULTS

Out of the 448 ICUs contacted, 90% (n=404) returned the questionnaire completely filled in. Sixty-six responders (16%) made use of TH for post-resuscitation care, and 4% used TH for other clinical scenarios (10 ICUs for traumatic brain injury; 5 ICUs for other reasons). More than half used TH not only for cardiac arrest subsequent to ventricular fibrillation (VF), but also for non-VF cardiac arrest with the duration of TH treatment being within the time suggested by advanced cardiac life support guidelines. On the other hand, 80% of questionnaire responders did not use TH, mainly because they felt they did not have enough data/experience (45%), or simply because they had never thought about it (18%).

CONCLUSIONS

Despite authoritative data supporting its effectiveness and safety, use of TH as part of the therapy in a post-resuscitation period in Italian ICUs remains low. The reasons for not using it are not completely justified and suggest that an educational program is advisable in order to boost the utilization of TH in Italy.

Therapeutic hypothermia for neonatal encephalopathy: a UK survey of opinion, practice and neuro-investigation at the end of 2007

BACKGROUND

The 2007 Cochrane review of therapeutic hypothermia for neonatal encephalopathy (NE) indicates a significant reduction in adverse outcome. UK National Institute for Clinical Excellence guidelines are awaited.

OBJECTIVE

To benchmark current opinion and practice to inform future strategies for optimal knowledge transfer for therapeutic hypothermia.

METHODS

A web based questionnaire (30 sections related to opinion and practice of management of NE) sent to the clinical leads of Level I, II and III neonatal units throughout the UK in November/December 2007.

RESULTS

One hundred and twenty-five (out of 195) UK neonatal units responded (response rate 66%). Ten percent, 37.5% and 51.5% responses were from level I, II and III units respectively. Twenty eight percent of all units provided therapeutic hypothermia locally (52% of level III units), however 80% of responders would offer therapeutic hypothermia if there was the facility. Overall, 57% of responders considered therapeutic hypothermia effective or very effective - similar for all unit levels; 43% considered more data are required. Regional availability of therapeutic hypothermia exists in 55% of units and 41% of units offer transfer to a regional centre for therapeutic hypothermia.

CONCLUSION

In the UK in 2007, access to therapeutic hypothermia was widespread although not universal. More than half of responders considered therapeutic hypothermia effective. Fifty-five percent of perinatal networks have the facility to offer therapeutic hypothermia. The involvement of national bodies may be necessary to ensure the adoption of therapeutic hypothermia according to defined protocols and standards; registration is important and will help ensure universal neurodevelopmental follow up.

Hypothermia following pediatric traumatic brain injury

Preclinical as well as clinical studies in traumatic brain injury (TBI) have established the likely association of secondary injury and outcome in adults in children following severe injury. Similarly, there is growing evidence in experimental laboratory studies that moderate hypothermia has a beneficial effect on outcome, though the exact mechanisms remain to be absolutely defined. The Pediatric TBI Guidelines provided the knowledge and background for standard management of children following severe TBI and highlighted that there are very few clinical studies to date. In particular with respect to temperature regulation and the use of hypothermia, initial findings of case series of small numbers were promising. Further preliminary randomized clinical trials, both single institution and multicenter, have provided the initial data on safety and efficacy, though larger, Phase III studies are necessary to ensure both the safety and efficacy of hypothermia in pediatric TBI prior to implementation as part of the standard of care. It is expected that hypothermia initiated early after severe TBI will have a protective effect on the pediatric brain and can be done safely, but this still remains to be definitively tested.

Neonatal encephalopathy: treatment with hypothermia

In this article, the role of hypothermia and neuroprotection for neonatal encephalopathy will be discussed. The incidence of encephalopathy due to hypoxia ischemia as well as the pathophysiology will be presented. The diagnosis of encephalopathy in full-term neonates will be discussed. The current management of brain injury that occurs with hypoxia ischemia and the role of hypothermia in preventing brain injury in fetal and neonatal animal models will be reviewed. The current data from randomized control trials of hypothermia as neuroprotection for full-term infants will be presented along with the results of meta-analyses of these trials. Lastly, the status of ongoing neonatal hypothermia trials will be summarized.

Induction of mild hypothermia in cardiac arrest survivors presenting with cardiogenic shock syndrome

BACKGROUND

Induction of mild hypothermia (MH) in patients resuscitated from cardiac arrest improves their outcome. However, benefits and risks of MH in patients who remain in cardiogenic shock after the return of spontaneous circulation (ROSC) are unclear. We analysed all cardiac arrest survivors who were treated with MH in our intensive coronary care unit (CCU) and compared the outcome of patients with cardiogenic shock syndrome (CSS) with those who were circulatory stable.

METHODS

We performed retrospective analysis of all consecutive cardiac arrest survivors treated by MH in our CCU from November 2002 to August 2006. They were classified into two groups, according to whether they met the criteria for cardiogenic shock or not before MH initiation.

RESULTS

Out of 56 consecutive patients, 28 fulfilled criteria of cardiogenic shock before MH initiation (group A) and 28 were relatively stable (group B). In-hospital mortality was 57.1% in group A and 21.4% in group B patients (P=0.013). Favourable neurological outcome anytime during hospitalization was found in 67.9% of group A patients and in 82.1% of group B subjects (P=0.355). Favourable discharge neurological outcome was reached in 39.3% in group A and in 71.4% in group B (P=0.031). The complication rate in both groups did not differ.

CONCLUSION

While in-hospital mortality in cardiac arrest survivors treated by MH was expectably higher in those with cardiogenic shock than in stable patients, the favourable neurological outcome during hospitalization was comparable in both groups. Therefore, induction of MH should be considered in cardiac arrest survivors with CSS after ROSC.

Survey of management of severe head injury in Canada

OBJECTIVE

To determine: 1. the degrees of consensus and disagreement among Canadian critical care clinicians regarding the appropriateness (benefit exceeding risk) of common therapeutic manoeuvres in patients with severe closed head injury (CHI), and 2. the frequency with which clinicians employed these manoeuvres.

METHODS

The study design was a systematic scenario-based survey of all neurosurgeons and critical care physicians treating patients with severe CHI in Canada.

RESULTS

In the scenario of acute epidural hematoma with mass effect, respondents agreed very strongly that surgery was appropriate. Clinicians reported mannitol and hypertonic saline as appropriate. Beyond these two interventions, agreement was less strong, and the use of the extraventricular drain (EVD), phenytoin, cooling, hyperventilation, nimodipine, and jugular venous oximetry (JVO) were of uncertain appropriateness. Steroids were considered inappropriate. In a scenario of diffuse axonal injury (DAI), clinicians agreed strongly that fever reduction, early enteral feeding, intensive glucose control, and cerebral perfusion pressure (CPP)-directed management were appropriate. The use of mannitol, hypertonic saline, EVD, JVO, narcotics and propofol were also appropriate. Neuromuscular blockade, surgery, and hyperventilation were of uncertain appropriateness. The appropriateness ratings of the interventions considered in the scenario of an intracranial contusion mirrored the DAI scenario. In general, correlations between the reported appropriateness and frequency of use of each intervention were very high. An exception noted was the use of the JVO. The correlation between CPP-guided therapy and the use of the EVD was weak.

CONCLUSIONS

This survey has described current practice with regard to treatment of patients with severe CHI. Areas of variation in perceived appropriateness were identified that may benefit from further evaluation. Suggested priorities for evaluation include the use of osmotic diuretics, anticonvulsants, and intracranial manometry.

Antiedema therapy in ischemic stroke

Life-threatening, space-occupying brain edema occurs in up to 10% of patients with supratentorial infarcts and is traditionally associated with a high mortality rate of up to 80%. Management of these patients is currently being changed to an earlier and more aggressive treatment regimen. Early surgical decompression has recently been proven effective to reduce mortality and increase the number of patients with a favorable outcome in randomized controlled trials and is now the "antiedema" therapy of first choice for patients with large middle cerebral artery infarction aged 60 years or younger. Several medical treatment strategies have been proposed to control brain edema and reduce intracranial pressure, including different osmotherapeutics, hyperventilation, tromethamine, hypothermia, and barbiturate coma. None of these treatments is supported by level 1 evidence of efficacy in clinical trials, and some of them may even be detrimental. Preliminary results on hypothermia for space-occupying hemispheric infarction are encouraging, but far from definitive.

IHAST II and the response of neuroanaesthetists

Deliberate mild hypothermia was first used in 1955 as an intraoperative technique to ameliorate new neurological deficits following cerebral aneursym clipping, and subsequently was also used following neonatal asphyxia, head trauma and cardiac arrest. The Intraoperative Hypothermia for Aneurysm Surgery Trial (IHAST II) randomized control trial was designed to determine the effectiveness of mild hypothermia to decrease neurological deficits following aneurysm surgery. No overall benefit was demonstrated in the hypothermic group versus normothermic group (67% versus 63% good outcome; p=0.32), with a higher rate of bacteraemia in the hypothermic group (5% versus 3%; p=0.05). We undertook a survey of Australasian and Asian neuroanaesthetists to determine whether their thermal management of patients undergoing cerebral aneursym clipping had changed in response to the IHAST II trial results.

Fever after subarachnoid hemorrhage: risk factors and impact on outcome

OBJECTIVE

To identify risk factors for refractory fever after subarachnoid hemorrhage (SAH), and to determine the impact of temperature elevation on outcome.

METHODS

We studied a consecutive cohort of 353 patients with SAH with a maximum daily temperature (T(max)) recorded on at least 7 days between SAH days 0 and 10. Fever (>38.3 degrees C) was routinely treated with acetaminophen and conventional water-circulating cooling blankets. We calculated daily T(max) above 37.0 degrees C, and defined extreme T(max) as daily excess above 38.3 degrees C. Global outcome at 90 days was evaluated with the modified Rankin Scale (mRS), instrumental activities of daily living (IADLs) with the Lawton scale, and cognitive functioning with the Telephone Interview of Cognitive Status. Mixed-effects models were used to identify predictors of T(max), and logistic regression models to evaluate the impact of T(max) on outcome.

RESULTS

Average daily T(max) was 1.15 degrees C (range 0.04 to 2.74 degrees C). The strongest predictors of fever were poor Hunt-Hess grade and intraventricular hemorrhage (IVH) (both p < 0.001). After controlling for baseline outcome predictors, daily T(max) was associated with an increased risk of death or severe disability (mRS > or = 4, adjusted OR 3.0 per degrees C, 95% CI 1.6 to 5.8), loss of independence in IADLs (OR 2.6, 95% CI 1.2 to 5.6), and cognitive impairment (OR 2.5, 95% CI 1.2 to 5.1, all p < or = 0.02). These associations were even stronger when extreme T(max) was analyzed.

CONCLUSION

Treatment-refractory fever during the first 10 days after subarachnoid hemorrhage (SAH) is predicted by poor clinical grade and intraventricular hemorrhage, and is associated with increased mortality and more functional disability and cognitive impairment among survivors. Clinical trials are needed to evaluate the impact of prophylactic fever control on outcome after SAH.

Hypothermia for the treatment of neonatal ischemic encephalopathy: is the genie out of the bottle?

Evidence suggests that hypothermia for hypoxic ischemic encephalopathy in the term neonate may decrease the risk of death or neurodevelopmental impairment. The objective of this study was to determine how hypothermia has been incorporated into practice. An anonymous survey was sent to medical directors of United States neonatal intensive care units (NICUs) in October 2005. We received completed surveys from 441 (54.5%) of 809 of NICUs. Only 6.4% of respondents used hypothermia. The most common method was total body cooling (64.3%) compared with head cooling (25%) or both (10.7%). At centers that did not offer hypothermia, 29% transferred infants to an institution that did. Centers that offered hypothermia were more likely at academic institutions (76.9%) compared with private practices (11.5%; p < 0.001). Hypothermia was more likely offered at institutions that offered extracorporeal membrane oxygenation (ECMO; 57%) than centers where ECMO was not offered (43%; p < 0.001). There has not been widespread use of hypothermia. There are a variety of protocols used. As results of further outcome studies become available, educational efforts and national practice guidelines will be essential.

Hypothermia pediatric head injury trial: the value of a pretrial clinical evaluation phase

BACKGROUND

The utility of a pretrial clinical evaluation or run-in phase prior to conducting trials of complex interventions such as hypothermia therapy following severe traumatic brain injury in children and adolescents has not been established.

METHODS

The primary objective of this study was to prospectively evaluate the ability of investigators to adhere to the clinical protocols of care including the cooling and rewarming procedures as well as management guidelines in patients with severe traumatic brain injury (Glasgow Coma Scale<or=8) treated with 24 h of hypothermia therapy. A secondary objective was to evaluate the ability of study research assistants to complete the study case report form using a procedures manual. The study was conducted at 18 sites in Canada, the United Kingdom and France prior to proceeding to a randomized controlled trial (RCT). After 2 patients were enrolled at each center, an independent clinical evaluation committee examined the process of care and the completeness of data collection. Centers were permitted to enroll patients in the RCT once they met pre-established adherence criteria.

RESULTS

Seventeen of the 18 centers completed the pretrial clinical evaluation phase demonstrating compliance with study procedures and proceeded to an RCT of hypothermia therapy. One center enrolled only 1 patient in the pretrial clinical evaluation phase due to small numbers of patients with traumatic brain injury, and therefore, did not proceed to the RCT. Three centers were required to enroll more than 2 patients in the pretrial clinical evaluation phase prior to proceeding to the RCT because of problems with adherence to the clinical protocols at two centers and the training of new study personnel at another center. Of the 39 patients enrolled during the pretrial clinical evaluation phase, 8 (20.5%) died and 22 (62.9%) had a good outcome defined as normal, mild or moderate disability assessed using the Pediatric Cerebral Performance Category score at 6 months following injury.

DISCUSSION

The pretrial clinical evaluation phase was useful to ensure compliance with complex hypothermia therapy and consensus-based clinical management guidelines of care successfully implemented across 17 of 18 centers. This study maneuver allowed us to complete a subsequent RCT in 225 children following severe traumatic brain injury.

Therapeutic hypothermia after cardiac arrest: a survey of practice in intensive care units in the United Kingdom

A telephone survey was carried out on the use of hypothermia as part of the management of unconscious patients following cardiac arrest admitted to United Kingdom (UK) intensive care units (ICUs). All 256 UK ICUs listed in the Critical Care Services Manual 2004 were contacted to determine how many units have implemented therapeutic hypothermia for unconscious patients admitted following cardiac arrest, how it is implemented, and the reasons for non-implementation. Two hundred and forty-six (98.4%) ICUs agreed to participate. Sixty-seven (28.4%) ICUs have cooled patients after cardiac arrest, although the majority of these have treated fewer than 10 patients. The commonest reasons given for not using therapeutic hypothermia in this situation are logistical or resource issues, or the perceived lack of evidence or consensus within individual ICU teams.

Therapeutic hypothermia utilization among physicians after resuscitation from cardiac arrest*

OBJECTIVE

We sought to evaluate current physician use of therapeutic hypothermia after cardiac arrest, to ascertain reasons for nonadoption of this treatment, and to determine current cooling techniques employed.

DESIGN

Web-based survey.

SETTING

International physician cohort in the United States, UK, and Finland.

SUBJECTS

Physicians (MD or DO) caring for resuscitated cardiac arrest patients.

INTERVENTIONS

An anonymous Web-based survey was distributed to physicians identified through United States-based critical care, cardiology, and emergency medicine directories and critical care networks in the UK and Finland. Recipients were queried regarding use of postresuscitation therapeutic hypothermia.

MEASUREMENTS AND MAIN RESULTS

Of the final 13,272 surveys actually distributed to physicians, 2,248 (17%) were completed. Most respondents were attending physicians (82%) at teaching hospitals (76%) who practiced critical care (35%), cardiology (20%), or emergency medicine (22%). Of all replies, 74% of United States respondents and 64% of non-United States respondents had never used therapeutic hypothermia. United States emergency medicine physician adoption of cooling was significantly less than that of United States intensivists (16% vs. 34%, p < .05). The most often cited reasons for nonuse by respondents were "not enough data," "not part of Advanced Cardiac Life Support guidelines," and "too technically difficult to use." Factors associated with increased use included non-United States residence, critical care specialty, and larger hospital size.

CONCLUSIONS

Physician utilization of cooling after cardiac arrest remains low. For improved adoption of therapeutic hypothermia, our data suggest that development of better cooling methodology and recent incorporation into resuscitation guidelines may improve use.

Pediatric critical care community survey of knowledge and attitudes toward therapeutic hypothermia in comatose children after cardiac arrest

OBJECTIVE

Therapeutic hypothermia improves neurologic outcome and survival after adult out-of-hospital cardiac arrest. To help us design a prospective hypothermia trial in children, we developed a survey to assess current knowledge and attitude of pediatric critical care providers regarding therapeutic hypothermia and potential impediments to implementing a prospective study.

DESIGN

Anonymous survey.

SETTING

Internet-based survey of pediatric critical care community.

INTERVENTIONS

None.

RESULTS

A total of 159 responders completed the survey. Most respondents (92%) were fellowship-trained in pediatric critical care, with 9.9 +/- 6.5 yrs of experience. Many (85%) worked in the United States; 89% were in large tertiary care centers with residency or fellowship training programs. Most (65%) were aware of the adult randomized trials of therapeutic hypothermia, but only 9% (always) or 38% (sometimes) utilize this therapy. The most common reason to use hypothermia was likelihood of patient recovery, absence of life-limiting disease, and presence of coma for >/=1 hr after resuscitation. The majority of responders using therapeutic hypothermia cool their patients to 33-35 degrees C for a duration ranging from as short as 12 hrs to as long as 96 hrs; 91% do not actively rewarm the patient. A majority (81%) agree that a randomized, controlled trial of therapeutic hypothermia in children is ethical, and 95% would be willing to randomize their patients. Finally, 81% thought that therapeutic hypothermia should be studied in other ischemic insults and not just cardiac arrest.

CONCLUSIONS

Despite widespread awareness of therapeutic hypothermia's beneficial effects after arrest, it is not widely used by pediatric critical care clinicians sampled in our survey. Among those using hypothermia, there is wide variation in methodology and end points of therapy. This seems to result from a lack of evidence, difficulty with the technique, and unavailability of explicit protocols. Pediatric studies are needed to assess the safety, feasibility, and effectiveness of therapeutic hypothermia after cardiac arrest and other causes of brain injury.

Induced hypothermia is underused after resuscitation from cardiac arrest: a current practice survey

BACKGROUND

Important recent work has demonstrated that the use of induced hypothermia can improve survival and neurologic recovery after cardiac arrest. We wished to ascertain the extent to which physicians were using this treatment, and what opinions are held by clinicians regarding its use.

METHODS

An internet-based survey of physicians was conducted, with physicians chosen at random from published directories of the Society for Academic Emergency Medicine, the American Thoracic Society, and the American Heart Association. Physicians were questioned regarding use of therapeutic hypothermia, methods employed, and/or reasons why they had not incorporated hypothermia into their care of cardiac arrest patients.

RESULTS

Completed surveys were collected from 265 physicians, including those practicing emergency medicine (41%), critical care (13%), and cardiology (24%). Respondents were geographically well distributed and the majority (94%) were at post-training level. Most respondents (78%) practiced at either larger referral hospitals or academic medical centers. When asked if they had ever used hypothermia following cardiac arrest, 87% said they had not. Among reasons cited for non-use, 49% felt that there were not enough data, 32% mentioned lack of incorporation of hypothermia into advanced cardiovascular life support (ACLS) protocols, and 28% felt that cooling methods were technically too difficult or too slow.

CONCLUSION

Despite compelling data supporting its use, hypothermia has yet to be broadly incorporated into physician practice. This highlights the need for improved awareness and education regarding this treatment option, as well as the need to consider hypothermia protocols for inclusion in future iterations of ACLS.

Traumatic brain injury: physiology, mechanisms, and outcome

PURPOSE OF REVIEW

This review on traumatic brain injury consolidates the substantial current literature available on the pathophysiology, mechanisms, developments, and their subsequent effects on outcome. In particular, it tries to conceptualize why our greatly improved understanding of pathophysiology and neurobiology in traumatic brain injury has not translated into clear outcome improvements.

RECENT FINDINGS

Early cerebral ischaemia has been characterized further, with ischaemic brain volume correlating with 6-month outcome. The Brain Trauma Foundation has revised perfusion pressure targets, and there are additional data on the outcome impact of brain tissue oxygen response and asymmetric patterns of cerebral autoregulation. Mechanistic studies have highlighted the role of inflammation and introduced concepts such as therapeutic vaccination and immune modulation. Experimental neurogenesis and repair strategies show promise. Despite continuing gains in knowledge, the experimental successes have not yet translated to the clinic. Indeed, several major articles have attempted to understand the clinical failure of highly promising strategies such as hypothermia, and set out the framework for further studies (e.g. addressing decompressive craniectomy). High-dose mannitol has shown promise in poor grade patients, while hypertonic saline has shown better intracranial pressure control. Negative results may be the consequence of ineffective therapies. However, there is a gathering body of work that highlights the outcome impact of subtle neurocognitive changes, which may not be quantified adequately by outcome measures used in previous trials. Such knowledge has also informed improved definition of mild traumatic brain injury, and allowed validation of management guidelines.

SUMMARY

The evidence base for current therapies in this heterogeneous patient group is being refined, with greater emphasis on long-term functional outcomes. Improved monitoring techniques emphasize the need for individualization of therapeutic interventions.

Balance of risk of therapeutic hypothermia

The complications of therapeutic hypothermia sometimes undermine its clinical effects. In this study we investigated the efficacy and safety of therapeutic hypothermia based on analysis of 20 severe head injury cases from 6 institutions treated with therapeutic hypothermia in 1999. The twenty patients with severe head injury were enrolled prospectively based on the following indications; Glasgow Coma Scale of 7 or less on admission, age 60 or younger, and systric BP over 100 mmHg. A control group consisting of 21 patients with severe head injury met the same criteria but were treated without therapeutic hypothermia in other institutions. Clinical benefit were evaluated by a comparison of clinical result in the two groups defined according to the Glasgow Outcome Scale six months after injury. The hypothermia group was divided into two groups based on a target temperature [mild hypothermia group: 32-34 degrees C (n = 10); very mild hypothermia group: 35-36 degrees C (n = 10)]. The complication rate, clinical results and the duration of therapeutic hypothermia were analyzed between two groups. In the hypothermia group, 12 patients obtained a favorable outcome (Good Recovery or Moderate Disabled in GOS) and the mortality rate was 35%. In the control group, however only 5 patients had a favorable outcome and the mortality rate was 57%. Comparison between mild hypothermia and very mild hypothermia groups revealed no difference in clinical outcome. In the hypothermia group, severe pneumonia was seen in three patients, all in the mild hypothermia group with a hypothermic duration of over 120 hours. Mild hypothermia should be ended within 120 hours to avoid severe complication. When long-lasting therapeutic hypothermia of more than 120 hours is planned, very mild hypothermia is the treatment of choice.

The influence of mild hypothermia on ICP, CPP and outcome in patients with primary and secondary brain injury

Aim of this study was to examine the hypothesis that only a subgroup of patients with lesser primary brain damage after severe head injury may benefit from therapeutic hypothermia. We prospectively analysed 72 patients with severe head injury, randomized into groups with (n = 37) and without (n = 35) hypothermia of 34 degrees C maintained for 72 hours. The influence of hypothermia on ICP, CPP and neurological outcome was analysed in the context of the extent of primary brain damage. Patients with normothermia and primary lesions (n = 17) values: GCS on admission 5 (median), ICP 18.9 (mean), CPP 73 (mean), GOS 4 (median). Patients with normothermia and extracerebral hematomas (n = 20): GCS 4, ICP 16, CPP 71, GOS 3. Patients with hypothermia and primary lesions (n = 21): GCS 4,62, ICP 10, 81, CPP 78,1, GOS 4. Patients with hypothermia and extracerebral hematomas (n = 14): GCS 5, ICP 13.2, CPP 78, GOS 5. Hypothermia decreased ICP and increased CPP regardless of the type of brain injury. Hypothermia was not able to improve outcome in patients with primary brain lesions but this pilot study suggests that it significantly improves outcome in patients with extracerebral hematomas.

Regional brain cooling induced by vascular saline infusion into ischemic territory reduces brain inflammation in stroke

The neuroprotective effect of hypothermia has long been recognized. Use of hypothermia for stroke therapy, which is currently being induced by whole body surface cooling, has been largely limited because of management problems and severe side effects (i.e., pneumonia). Our recent studies have demonstrated the significant therapeutic value of local brain cooling in the ischemic territory prior to reperfusion in stroke. The goal of this study was to determine if cerebral local cooling infusion could reduce stroke-mediated brain injury by inhibiting inflammatory responses. A hollow filament was used to block the middle cerebral artery (MCA) for 3 hours, and then to locally infuse the ischemic territory with 6 ml cold saline (20 degrees C) for 10 min prior to 48-h reperfusion. This cold saline infusion significantly ( P<0.01) reduced temperature of the MCA supplied territory (in cerebral cortex from 37.2+/-0.1 degrees C to 33.4+/-0.4 degrees C, in striatum from 37.5+/-0.2 degrees C to 33.9+/-0.4 degrees C), with the hypothermia remaining for at least 45 min after reperfusion. Consequently, significant ( P<0.01) reductions in endothelial expression of intracellular adhesion molecule-1 (ICAM-1), the key step for inflammatory progress, as well as leukocyte infiltration, were evident in both cortex and striatum after reperfusion. As a control, ischemic rats received the same amount of cold saline systemically through a femoral artery. A mild hypothermia was induced in the cerebral cortex (35.3+/-0.2 degrees C) but not in the striatum (36.8+/-0.2 degrees C). The reduced cortical temperature returned to normal within 5 min. Brain temperature in ischemic rats perfused locally with saline at 37 degrees C remained normal. Intensive expression of ICAM-1 and accumulation of leukocytes was observed in ischemic control groups without brain cooling infusion. In conclusion, brain hypothermia induced by local pre-reperfusion infusion ameliorated brain inflammation from stroke.

Impact of Age on the Outcome of Pulmonary Vein Isolation for Atrial Fibrillation Using Circular Mapping Technique and Cooled-Tip Ablation Catheter:

INTRODUCTION

A retrospective analysis was performed to define the impact of age on the outcomes and complications in patients undergoing pulmonary vein isolation (PVI). PVI is an evolving technique for the management of atrial fibrillation (AF). The impact of age on the risks, outcomes, and complications of PVI has not been well defined.

METHODS AND RESULTS

A total of 323 patients (259 men and 64 women; age 18-79 years) underwent PVI for treatment of drug-refractory symptomatic AF. An ostial isolation of the pulmonary veins was done using a cooled-tip ablation catheter guided by circular mapping. The patients were divided into three groups based on age (group I: <50 years, group II: 51-60 years, group III: >60 years) and the results were compared. There were 106 patients in group I, 114 patients in group II, and 103 patients in group III (mean age 41.3 +/- 7.8 years, 55.4 +/- 2.75 years, and 66.6 +/- 4.18 years, respectively) who underwent PVI for paroxysmal (53.8%), persistent (10.8%), or permanent (35.3%) AF. Baseline characteristics were similar except for a higher prevalence of hypertension and/or structural heart disease in groups II and III (58% and 63% vs 33% in group I, respectively). The procedural variables were similar in all age groups. The overall risk of complications was similar in the three groups, except that the risk of stroke was significantly higher in patients >60 years of age (3% vs 0%; P < 0.05). The recurrence rates of AF were similar in the three age groups (15.1%, 16.7%, and 18.4%, respectively; P > 0.05). The risk of severe pulmonary vein stenosis (1.8%, 2.6%, and 0.9%, respectively) was low and did not vary with age.

CONCLUSION

PVI is a safe and effective treatment for patients with drug-refractory symptomatic AF, and its benefits extend to all age groups. The risk of procedural complications, especially thromboembolic events, appears to be higher in the elderly age group. This observation needs to be considered while assessing potential candidates for the procedure.

The significance of hypothermia in preserving ischemic myocardium

The clinical use of mild hypothermia to preserve ischemic cardiac and cerebral tissue continues to grow in popularity. This is a result of the known fact that hypothermia reduces myocardial oxygen demands more than any other intervention. The Advanced Life Support (ALS) Task Force of the International Liaison Committee on Resuscitation (ILCOR) made the following recommendations a year ago, in October 2002: "Unconscious adult patients with spontaneous circulation after out-of-hospital cardiac arrest should be cooled to 32 degrees C to 34 degrees C for 12 to 24 hours when the initial rhythm was VF," or in-hospital even when arrest is due to other rhythms. Therapeutic use of hypothermia is in progress.

Long-term hypothermia in patients with severe brain edema after poor-grade subarachnoid hemorrhage: feasibility and intensive care complications

The purpose was to evaluate the feasibility and intensive care complications of long-term hypothermia (>72 hours) in the treatment of severe brain edema after poor-grade subarachnoid hemorrhage (SAH) Hunt and Hess grade 4 to 5. Among 156 patients with SAH, 21 patients were treated with mild hypothermia (33.0 to 34.0 degrees C) combined with barbiturate coma because of severe brain edema and elevated intracranial pressure (>15 mm Hg) after early aneurysm clipping. Hypothermia was sustained for at least 24 hours after maintaining an intracranial pressure of <15 mm Hg. Nine patients were treated for <72 hours (group 1: mean 42.2 hours, range 8-66 hours) and 12 for >72 hours (group 2: mean 153.9 hours, range 78-400 hours). Three patients (14%) died during the hypothermia treatment. Good functional outcome after 3 months (Glasgow Outcome Score 4-5) was achieved in 10 patients (48%). The outcome did not differ between the two groups. All patients developed severe infections. In group 2 the mean value of minimal leukocyte counts during hypothermia was significantly lower (6.9 vs. 11.8 x 109/L; P = 0.001), and thrombocytopenia (<150 x 109/L) occurred significantly more often (48 vs. 33%; P = 0.032). In 48% of patients with poor-grade SAH, good functional outcome was achieved with combined mild hypothermia and barbiturate coma after early aneurysm surgery. This may be a feasible treatment even for longer than 72 hours. All patients developed severe infections as potentially hazardous side effects. To determine whether mild hypothermia alone is effective in the treatment of severe SAH patients, controlled studies to compare the effects of barbiturate coma alone, mild hypothermia alone, and combined barbiturate coma with hypothermia are needed.