Association Between a Single General Anesthesia Exposure Before Age 36 Months and Neurocognitive Outcomes in Later Childhood

IMPORTANCE

Exposure of young animals to commonly used anesthetics causes neurotoxicity including impaired neurocognitive function and abnormal behavior. The potential neurocognitive and behavioral effects of anesthesia exposure in young children are thus important to understand.

OBJECTIVE

To examine if a single anesthesia exposure in otherwise healthy young children was associated with impaired neurocognitive development and abnormal behavior in later childhood.

DESIGN, SETTING, AND PARTICIPANTS

Sibling-matched cohort study conducted between May 2009 and April 2015 at 4 university-based US pediatric tertiary care hospitals. The study cohort included sibling pairs within 36 months in age and currently 8 to 15 years old. The exposed siblings were healthy at surgery/anesthesia. Neurocognitive and behavior outcomes were prospectively assessed with retrospectively documented anesthesia exposure data.

EXPOSURES

A single exposure to general anesthesia during inguinal hernia surgery in the exposed sibling and no anesthesia exposure in the unexposed sibling, before age 36 months.

MAIN OUTCOMES AND MEASURES

The primary outcome was global cognitive function (IQ). Secondary outcomes included domain-specific neurocognitive functions and behavior. A detailed neuropsychological battery assessed IQ and domain-specific neurocognitive functions. Parents completed validated, standardized reports of behavior.

RESULTS

Among the 105 sibling pairs, the exposed siblings (mean age, 17.3 months at surgery/anesthesia; 9.5% female) and the unexposed siblings (44% female) had IQ testing at mean ages of 10.6 and 10.9 years, respectively. All exposed children received inhaled anesthetic agents, and anesthesia duration ranged from 20 to 240 minutes, with a median duration of 80 minutes. Mean IQ scores between exposed siblings (scores: full scale = 111; performance = 108; verbal = 111) and unexposed siblings (scores: full scale = 111; performance = 107; verbal = 111) were not statistically significantly different. Differences in mean IQ scores between sibling pairs were: full scale = -0.2 (95% CI, -2.6 to 2.9); performance = 0.5 (95% CI, -2.7 to 3.7); and verbal = -0.5 (95% CI, -3.2 to 2.2). No statistically significant differences in mean scores were found between sibling pairs in memory/learning, motor/processing speed, visuospatial function, attention, executive function, language, or behavior.

CONCLUSIONS AND RELEVANCE

Among healthy children with a single anesthesia exposure before age 36 months, compared with healthy siblings with no anesthesia exposure, there were no statistically significant differences in IQ scores in later childhood. Further study of repeated exposure, prolonged exposure, and vulnerable subgroups is needed.

Neurotoxicity, general anesthesia in young children, and a survey of current pediatric anesthesia practice at US teaching institutions

BACKGROUND

Recent articles in both scholarly journals and the lay press about the topic of anesthetic related neurotoxicity have increased the awareness and discussion of this topic with parents and other pediatric medical specialties (i.e., surgeons, radiologists, and pediatricians).

AIM

The purpose of the present study was to survey how a subset of pediatric anesthesia departments in the US have responded to the issue of anesthetic related neurotoxicity in terms of clinical practice, training and communication with other medical specialties, and the frequency and timing of discussions with families.

METHODS

A survey consisting of 22 questions was sent to PALC (Pediatric Anesthesia Leadership Council) & PAPDA (Pediatric Anesthesia Program Directors Association) via SurveyMonkey. The survey was divided into sections on Anesthesia Faculty/Trainees, Parents and Non-Anesthesia Providers. Responses to the survey were solicited via email to PALC and PAPDA, and then followed up with reminders to individual emails using the mailing lists of both organizations.

RESULTS

The results of this survey demonstrate that pediatric anesthesia programs around the US do not have a consistent approach in managing the topic of anesthesia-related neurotoxicity with pediatric anesthesiologists, anesthesiology residents, pediatric anesthesiology fellows and their non-anesthesia medical and surgical colleagues, as well as the discussion of this topic with parents.

CONCLUSION

A significant need exists to provide information to other pediatric professionals and parents. A consistent message from all providers that includes what is known, and indeed more importantly what is not known may be a useful approach.

Does obesity prolong anesthesia in children undergoing common ENT surgery?

OBJECTIVES

To report the epidemiology of obesity in a pediatric surgical population and determine whether obesity is a risk factor for longer anesthesia duration.

BACKGROUND

Childhood obesity is a significant public health problem in the United States. Epidemiologic studies on pediatric surgical populations have been limited to states with very high prevalence of adult obesity (Michigan, Texas). Data from other states and more recent data since 2006 are unavailable.

METHODS

We examined anesthesia records for surgical patients age 2-18 years at Columbia University Medical Center from January 2009 to December 2010. Patients undergoing bariatric surgery or those with records missing preoperative height or weight data were excluded. Body mass index (BMI) was calculated as weight (kg)/height (m(2) ). BMI ≥95th percentile according to national growth charts were considered obese.

RESULTS

We reviewed 9522 patients of which 1639 were obese (17.2%). The sex-age category interaction on obesity was not significant using logistic regression (P = 0.11). Among surgical groups, the otolaryngology (ENT) cohort had the highest obesity rate (21.7%, 360/1656). Obese children who had tonsillectomy, adenoidectomy, or both did not have a prolonged anesthetic (P = 0.33) or surgical duration (P = 0.61) compared with nonobese children, adjusting for surgeon, season, surgical procedure code, and ASA status.

CONCLUSION

Children presenting for surgery, particularly the ENT cohort, have a high prevalence of obesity. Obese and nonobese children who had tonsillectomy, adenoidectomy, or both had comparable durations of anesthesia. Therefore, obesity did not lead to longer anesthetic duration.

Pediatric anesthesia and neurodevelopmental impairments: a Bayesian meta-analysis

Experimental evidence of anesthesia-induced neurotoxicity has caused serious concern about the long-term effect of commonly used volatile anesthetic agents on young children. Several observational studies based on existing data have been conducted to address this concern with inconsistent results. We conducted a meta-analysis to synthesize the epidemiologic evidence on the association of anesthesia/surgery with neurodevelopmental outcomes in children. Using Bayesian meta-analytic approaches, we estimated the synthesized odds ratios (OR) and 95% credible interval (CrI) as well as the predictive distribution of a future study given the synthesized evidence. Data on 7 unadjusted and 6 adjusted measures of association were abstracted from 7 studies. The synthesized OR based on the 7 unadjusted measures for the association of anesthesia/surgery with an adverse behavioral or developmental outcome was 1.9 (95% CrI, 1.2-3.0). The most likely unadjusted OR from a future study was estimated to be 2.2 (95% CrI, 0.6-6.1). The synthesized OR based on the 6 adjusted measures for the association of anesthesia/surgery with an adverse behavioral or developmental outcome was 1.4 (95% CrI, 0.9-2.2). The most likely adjusted OR from a future study was estimated to be 1.5 (95% CrI, 0.5-4.0). We conclude that existent epidemiologic evidence suggests a modestly elevated risk of adverse behavioral or developmental outcomes in children who were exposed to anesthesia/surgery during early childhood. The evidence, however, is considerably uncertain.

Long-term differences in language and cognitive function after childhood exposure to anesthesia

BACKGROUND

Over the past decade, the safety of anesthetic agents in children has been questioned after the discovery that immature animals exposed to anesthesia display apoptotic neurodegeneration and long-term cognitive deficiencies. We examined the association between exposure to anesthesia in children under age 3 and outcomes in language, cognitive function, motor skills, and behavior at age 10.

METHODS

We performed an analysis of the Western Australian Pregnancy Cohort (Raine) Study, which includes 2868 children born from 1989 to 1992. Of 2608 children assessed, 321 were exposed to anesthesia before age 3, and 2287 were unexposed.

RESULTS

On average, exposed children had lower scores than their unexposed peers in receptive and expressive language (Clinical Evaluation of Language Fundamentals: Receptive [CELF-R] and Expressive [CELF-E]) and cognition (Colored Progressive Matrices [CPM]). After adjustment for demographic characteristics, exposure to anesthesia was associated with increased risk of disability in language (CELF-R: adjusted risk ratio [aRR], 1.87; 95% confidence interval [CI], 1.20-2.93, CELF-E: aRR, 1.72; 95% CI, 1.12-2.64), and cognition (CPM: aRR, 1.69; 95% CI, 1.13-2.53). An increased aRR for disability in language and cognition persisted even with a single exposure to anesthesia (CELF-R aRR, 2.41; 95% CI, 1.40-4.17, and CPM aRR, 1.73; 95% CI, 1.04-2.88).

CONCLUSIONS

Our results indicate that the association between anesthesia and neuropsychological outcome may be confined to specific domains. Children in our cohort exposed to anesthesia before age 3 had a higher relative risk of language and abstract reasoning deficits at age 10 than unexposed children.

Citrullinated vimentin stimulates proliferation, pro-inflammatory cytokine secretion, and PADI4 and RANKL expression of fibroblast-like synoviocytes in rheumatoid arthritis

OBJECTIVES

We aimed to investigate the possible effects of vimentin (Vim) and citrullinated Vim (cVim) on proliferation capacity, pro-inflammatory cytokine secretion, and the expression of peptidylarginine deiminase type 4 (PADI4) and receptor activator of nuclear factor kappa B ligand (RANKL) in cultured fibroblast-like synoviocytes (FLSs) from rheumatoid arthritis (RA) and osteoarthritis (OA) patients.

METHOD

Human native Vim was citrullinated with rabbit PAD in vitro and detected using a Western blot assay with anti-modified citrulline antibody (anti-MC Ab). FLSs from RA or OA synovial samples were stimulated with Vim or cVim. Cell proliferation capacity was determined using the Celltiter 96 AQueous cell proliferation assay. The concentrations of tumour necrosis factor (TNF)-α, interleukin (IL)-1, and IL-17 were measured by enzyme-linked immunosorbent assay (ELISA). The expression of PADI4 and RANKL was measured by real-time polymerase chain reaction (RT-PCR) and a Western blot assay.

RESULTS

Our Western blot assay with anti-MC Ab indicated that the amount of cVim increased significantly after Vim had been incubated with rabbit PAD in vitro. The proliferation capacity and secretion of TNF-α and IL-1 were significantly enhanced in the FLSs of RA patients when treated with cVim. However, when treated with Vim, an inhibitory effect on the proliferation capacity was noted in the FLSs from RA and also from OA patients. cVim significantly increased the expression of PADI4 and RANKL in the FLSs from RA patients.

CONCLUSION

cVim seems to have remarkable biological effects on RA as confirmed by the stimulation of proliferation capacity, pro-inflammatory cytokine secretion, and PADI4 and RANKL expression in the FLSs of RA patients.

Excess comorbidities associated with malignant hyperthermia diagnosis in pediatric hospital discharge records

BACKGROUND

Case reports have linked malignant hyperthermia (MH) to several genetic diseases.

OBJECTIVE/AIM

The objective of this study was to quantitatively assess excess comorbidities associated with MH diagnosis in pediatric hospital discharge records.

PATIENTS AND METHODS

Data for this study came from the Kids' Inpatient Database (KID) for the years 2000, 2003, and 2006. The KID contains an 80% random sample of patients under the age of 21 discharged from short-term, non-Federal hospitals in the United States, with up to 19 diagnoses recorded for each patient. Using all pediatric inpatients as the reference, we calculated the standardized morbidity ratios (SMRs) and 95% confidence intervals (CIs) for children with MH diagnosis according to major disease groups and specific medical conditions.

RESULTS

Of the 5,916,989 nonbirth-related hospital discharges studied, 175 had a recorded diagnosis of MH. Compared with the general pediatric inpatient population, children with MH diagnosis were significantly more likely to be diagnosed with diseases of the musculoskeletal system and connective tissue (SMR 5.7; 95% CI: 3.9-7.9), diseases of the circulatory system (SMR 3.3; 95% CI: 2.1-4.8), and congenital anomalies (SMR 3.2; 95% CI: 2.3-4.4). The specific diagnosis that was most strongly associated with MH was muscular dystrophies (SMR 31.3; 95% CI 12.6-64.6).

CONCLUSIONS

Diseases of the musculoskeletal system and connective tissue are significantly associated with MH diagnosis in children. Further research is warranted to determine the clinical utility of these comorbidities in assessing MH susceptibility in children.

Early childhood exposure to anesthesia and risk of developmental and behavioral disorders in a sibling birth cohort

BACKGROUND

In vitro and in vivo studies of anesthetics have demonstrated serious neurotoxic effects on the developing brain. However, the clinical relevance of these findings to children undergoing anesthesia remains unclear. Using data from a sibling birth cohort, we assessed the association between exposure to anesthesia in the setting of surgery in patients younger than 3 years and the risk of developmental and behavioral disorders.

METHODS

We constructed a retrospective cohort of 10,450 siblings who were born between 1999 and 2005 and who were enrolled in the New York State Medicaid program. The exposed group was 304 children without a history of developmental or behavioral disorders who underwent surgery when they were younger than 3 years. The unexposed group was 10,146 children who did not receive any surgical procedures when they were younger than 3 years. Exposed children were entered into analysis at the date of surgery. Unexposed children were entered into analysis at age 10 months (the mean age at which exposed children underwent surgery). Both exposed and unexposed children were followed until diagnosis with a developmental or behavioral disorder, loss to follow-up, or the end of 2005. The association of exposure to anesthesia with subsequent developmental and behavioral disorders was assessed with both proportional hazards modeling, and pair-matched analysis.

RESULTS

The incidence of developmental and behavioral disorders was 128.2 diagnoses per 1000 person-years for the exposed cohort and 56.3 diagnoses per 1000 person-years for the unexposed cohort. With adjustment for sex and history of birth-related medical complications, and clustering by sibling status, the estimated hazard ratio of developmental or behavioral disorders associated with any exposure to anesthesia when they were younger than 3 years was 1.6 (95% confidence interval [CI]: 1.4, 1.8). The risk increased from 1.1 (95% CI: 0.8, 1.4) for 1 operation to 2.9 (94% CI: 2.5, 3.1) for 2 operations and 4.0 (95% CI: 3.5, 4.5) for ≥3 operations. The relative risk in a matched analysis of 138 sibling pairs was 0.9 (95% CI: 0.6, 1.4).

CONCLUSION

The risk of being subsequently diagnosed with developmental and behavioral disorders in children who were enrolled in a state Medicaid program and who had surgery when they were younger than 3 years was 60% greater than that of a similar group of siblings who did not undergo surgery. More tightly matched pairwise analyses indicate that the extent to which the excess risk is causally attributable to anesthesia or mediated by unmeasured factors remains to be determined.

Anesthetic-specific electroencephalographic patterns during emergence from sevoflurane and isoflurane in infants and children

BACKGROUND

Devices that monitor the depth of anesthesia are increasingly used to titrate sedation and avoid awareness during anesthesia. Many of these monitors are based upon electroencephalography (EEG) collected from large adult reference populations and not pediatric populations (Anesthesiology, 86, 1997, 836; Journal of Anaesthesia, 92, 2004, 393; Anesthesiology, 99, 2003, 34). We hypothesized that EEG patterns in children would be different from those previously reported in adults and that they would show anesthetic-specific characteristics.

METHODS

This prospective observational study was approved by the Institutional Review Board, and informed written consent was obtained. Patients were randomized to receive maintenance anesthesia with isoflurane or sevoflurane. EEG data collection included at least 10 min at steady-state maintenance anesthesia. The EEG was recorded continuously through emergence until after extubation. A mixed model procedure was performed on global and regional power by pooled data analysis and by analyzing each anesthetic group separately. Statistical significance was defined as P < 0.05.

RESULTS

Thirty-seven children completed the study (ages 22 days-3.6 years). Isoflurane and sevoflurane had different effects on global and regional EEG power during emergence from anesthesia, and frontal predominance patterns were significantly different between these two anesthetic agents.

CONCLUSIONS

The principal finding of the present study was that there are anesthetic-specific and concentration-dependent EEG effects in children. Depth-of-anesthesia monitors that utilize algorithms based on the EEGs of adult reference populations therefore may not be appropriate for use in children.

Intraoperative reported adverse events in children

BACKGROUND

Significant intraprocedural adverse events (AE) are reported in children who receive anesthesia for procedures outside the Operating Rooms (NORA). No study, so far, has characterized AE in children who receive anesthesia in the operating rooms (ORA) and NORA when anesthesia care is provided by the same team in a consistent manner.

OBJECTIVE/AIM

We used the same patient-specific Quality Assurance questionnaires (QAs), to elucidate incidences of intraoperative reported AE for children receiving anesthesia in NORA and ORA locations. Through multivariate logistic regression analysis, we assessed the association between patient's AE risk and procedure's location while adjusting for American Society of Anesthesiologists (ASA) status, age, and unscheduled nature of the procedure.

METHODS/MATERIALS

After Institutional Review Board approval, we used returned QAs of patients under 21 years, who received anesthesia from our pediatric anesthesia faculty from May 1 2006 through September 30, 2007. We analyzed QA data on: service location, unscheduled/scheduled procedure, age, ASA status, presence, and type of AE. We excluded QAs with incomplete information on date, location, age, and ASA status.

RESULTS

We included 8707 cases, with 3.5% incidence of reported AE. We had 1898 NORA and 6808 ORA cases with AE incidence of 2.5% and 3.7%, respectively. Multivariate regression analysis revealed that patients with higher ASA status or younger age had higher incidence of reported AE, irrespective of location or unscheduled nature of the procedure. The most common AE type, for both sites, was respiratory related (1.9%).

CONCLUSIONS

Pediatric reported AE incidence was comparable for NORA and ORA locations. Younger age or higher ASA status are associated with increased risk of AE.

Epidemiology of anesthesia-related mortality in the United States, 1999-2005

BACKGROUND

Previous research on anesthesia-related mortality in the United States was limited to data from individual hospitals. The purpose of this study was to examine the epidemiologic patterns of anesthesia-related deaths at the national level.

METHODS

The authors searched the International Classification of Diseases, 10th Revision manuals for codes specifically related to anesthesia/anesthetics. These codes were used to identify anesthesia-related deaths from the US multiple-cause-of-death data files for the years 1999-2005. Rates from anesthesia- related deaths were calculated based on population and hospital surgical discharge data.

RESULTS

The authors identified 46 anesthesia/anesthetic codes, including complications of anesthesia during pregnancy, labor, and puerperium (O29.0 -O29.9, O74.0-74.9, O89.0-O89.9), overdose of anesthetics (T41.0 -T41.4), adverse effects of anesthetics in therapeutic use (Y45.0, Y47.1, Y48.0 - Y48.4, Y55.1), and other complications of anesthesia (T88.2- T88.5, Y65.3). Of the 2,211 recorded anesthesia-related deaths in the United States during 1999-2005, 46.6% were attributable to overdose of anesthetics; 42.5% were attributable to adverse effects of anesthetics in therapeutic use; 3.6% were attributable to complications of anesthesia during pregnancy, labor, and puerperium; and 7.3% were attributable to other complications of anesthesia. Anesthesia complications were the underlying cause in 241 (10.9%) of the 2,211 deaths. The estimated rates from anesthesia-related deaths were 1.1 per million population per year (1.45 for males and 0.77 for females) and 8.2 per million hospital surgical discharges (11.7 for men and 6.5 for women). The highest death rates were found in persons aged 85 yr and older.

CONCLUSION

Each year in the United States, anesthesia/anesthetics are reported as the underlying cause in approximately 34 deaths and contributing factors in another 281 deaths, with excess mortality risk in the elderly and men.

The housekeeping gene (GA3PDH) and the long interspersed nuclear element (LINE) in the blood and organs of rats treated with cocaine

Housekeeping genes are necessary for maintenance of the vital activity of the cells of any phylum of organisms. Transposons or mobile genetic elements are eurysynusic in nature. Thus, the role of these and other genes in the pathogenesis of many diseases and of drug addiction in particular is being investigated. The goal of the work is to determine the influence of cocaine on the activity of GA3PDH and on a representative of the LINE family (L1Rn) in plasma, and in a pellet of blood cells, and in the organs of rats. Gene expression was evaluated by RT-PCR. The GA3PDH (452-bp fragment) was predictably found in plasma, in a pellet of blood cells, and in organs. Its quantity in plasma was greater in the experimental groups than in the control. In a pellet of blood cells and in organs, the GA3PDH activity between the different groups of animals essentially did not differ. The L1Rn fragment (319 bp) in plasma was not found. The expression of L1Rn was much higher in a pellet of blood cells and in organs of experimental animals. These experiments have shown the presence of GA3PDH in the plasma of the controls and an increase in quantity in the plasma of experimental animals. The activation of LINE in a pellet of blood cells of rats and in organs under the influence of cocaine has been demonstrated. Apparently, a recruitment phenomenon of housekeeping genes and transposons is possible in the pathogenesis of drug addiction.

Serum Cardiac Troponin-I Elevation in Neonatal Cardiac Surgery is Lesion-Dependent

OBJECTIVE

Serum cardiac troponin-I (cTn-I) is a marker for myocardial injury in adults that undergoes developmental isoform change. To determine its utility as a myocardial injury marker in neonates, the authors examined the perioperative pattern of cTn-I elevation in neonates undergoing surgical repair for hypoplastic left-heart syndrome (HLHS) and transposition of great arteries (TGA).

DESIGN

A prospective cohort study.

SETTING

The study was performed in a tertiary teaching hospital that is a major referral center for congenital cardiac surgery.

PATIENTS

Forty-five neonates were enrolled, 17 with HLHS, 15 with TGA with intact septum (TGA + IVS), 8 with TGA with ventricular septal defect (TGA + VSD), and 5 neonates undergoing extracardiac surgery who did not require cardiopulmonary bypass (CPB).

INTERVENTIONS

None.

RESULTS

Preoperative cTn-I was elevated in all neonates undergoing cardiac surgery with CPB. Increases in postoperative cTn-I correlated with duration of aortic cross-clamp application and CPB. Peak elevation in serum cTn-I occurred between 6 and 24 hours postoperatively in all neonates after cardiac surgery. The perioperative pattern of cTn-I was different in TGA + VSD (peak cTn-I = 10.9 +/- 5.9 ng/mL) compared with HLHS (peak cTn-I = 4.62 +/- 3.4 ng/mL) and TGA + IVS (peak cTn-I = 4.46 +/- 3.5 ng/mL).

CONCLUSION

It was found that perioperative elevations in serum cTn-I in neonates with TGA and HLHS were influenced by duration of aortic cross-clamp application, CPB, and the presence of VSD.

Dysfunction of atrial and B-type natriuretic peptides in congenital univentricular defects

OBJECTIVE

To examine whether children with univentricular defects have intrinsic dysfunction in the natriuretic peptide system.

METHODS

We compared plasma levels of the fluid-regulating hormone vasopressin (antidiuretic hormone), aldosterone, atrial natriuretic peptide, and brain natriuretic peptide in children with congenital univentricular and biventricular defects. We enrolled 27 patients with univentricular defects and 27 patients with biventricular cardiac defects. Children who underwent Fontan and Glenn procedures were considered as patients with univentricular cardiac defects; children who underwent repair of tetralogy of Fallot or subaortic stenosis were considered as controls with biventricular defects.

RESULTS

Preoperative plasma atrial natriuretic peptide, brain natriuretic peptide, antidiuretic hormone, and aldosterone were comparable in both groups. Although plasma cyclic guanosine monophosphate levels were comparable between groups, there was a significant correlation between molar concentrations of plasma cyclic guanosine monophosphate and plasma atrial natriuretic peptide ( r = 0.42) and brain natriuretic peptide ( r = 0.44) in the biventricular group, but not in the univentricular group ( r = 0.19 for atrial natriuretic peptide; r = 0.13 for brain natriuretic peptide). All patients had a significant postoperative increase in plasma antidiuretic hormone. A significant postoperative increase in plasma brain natriuretic peptide was found in the patients with biventricular, but not univentricular, defects. In contrast, a significant increase in plasma aldosterone was observed only in the patients with univentricular defects.

CONCLUSIONS

There were distinct differences between univentricular and biventricular groups in their perioperative plasma fluid-regulating hormone responses. Specifically, patients with univentricular defects may have abnormal natriuretic peptide secretion and function. The natriuretic dysfunction may be on the basis of hypoplastic ventricular development.

Extracellular receptor kinase and cAMP response element binding protein activation in the neonatal rat heart after perinatal cocaine exposure

Prenatal exposure to cocaine has been shown to induce an increase in the myocardial expression and activation of the cAMP response binding protein (CREB), a transcriptional factor that has been shown to regulate gene expression. Several different kinases, including protein kinase A, calcium calmodulin kinase II, and mitogen-activated protein kinase can induce phosphorylation of CREB at serine 133, a necessary step for CREB activation. We examined whether the mitogen-activated protein kinase-extracellular receptor kinase (ERK) pathway may be involved in mediating the serine 133 CREB phosphorylation in cardiac nuclei after perinatal cocaine exposure. Pregnant rats were treated daily with saline or cocaine at 60 mg/kg (C60) by intragastric administration during the entire gestational period, and treatment was continued in the nursing dams after delivery until the time of the study. Nuclear extracts were isolated from hearts of 1-d- and 7-d-old neonatal rats. We performed immunoblotting experiments using an antibody that recognized CREB with phosphorylation specifically at the serine 133 site and an antibody that recognized both the phosphorylated and the unphosphorylated forms of CREB, as well as antibodies for total ERK, phospho-ERK, total ribosomal S6 kinase 1 (RSK1), RSK2, and phospho-RSK. We assessed the interaction of RSK with CREB or CREB-binding protein by performing co-immunoprecipitation experiments. We found that perinatal cocaine exposure increased both phospho-ERK and phospho-RSK expression, indicative of an increased activity of these two enzymes. Furthermore, we demonstrated that phospho-RSK was immunoprecipitated with CREB in all neonatal cardiac nuclei and that the greatest interaction was found in day 7 hearts after perinatal cocaine exposure. Our results thus illustrate that the ERK-RSK pathway was active in the postnatal rat heart at 1 and 7 d of age and that this pathway may mediate the increase in myocardial CREB activation after perinatal cocaine exposure in the day 7 hearts.

Severe Hypotension in the Prone Position in a Child with Neurofibromatosis, Scoliosis and Pectus Excavatum Presenting for Posterior Spinal Fusion

A 34-mo-old boy with neurofibromatosis, scoliosis, and pectus excavatum developed severe hypotension when positioned prone. A magnetic resonance image study revealed neurofibromas encircling the great vessels. During the next anesthetic the patient was placed in the prone position on transverse bolsters and hypotension ensued again. A transesophageal echocardiogram (TEE) revealed compression of the right ventricle by the sternum. When the child was turned supine, the blood pressure returned to baseline. The patient was returned to the prone position, this time with bolsters placed longitudinally, without problem. This case supports a cardiac evaluation, possible intraoperative TEE, and avoidance of sternal pressure in patients with chest wall deformities requiring prone positioning.

IMPLICATIONS

A child with neurofibromatosis, scoliosis, and a chest wall deformity presenting for spinal fusion developed severe hypotension while prone. This was due to compression of the heart by the sternum, not compression of the great vessels by neurofibromas. Sternal pressure in prone patients with chest wall deformities should be avoided. Unique management included the use of transesophageal echocardiography to determine the cause of the hypotension.

Cardiac memory is associated with decreased levels of the transcriptional factor CREB modulated by angiotensin II and calcium

Cardiac memory (CM) has short- (STCM) and long-term (LTCM) components modulated by calcium and angiotensin II. LTCM is associated with reduced Ito and Kv4.3 mRNA levels. Because the cAMP response element binding protein, CREB, contributes to CNS memory transcription, we hypothesized that it might be a transcriptional factor in CM, influenced by calcium and angiotensin II. We studied STCM in dogs that were AV sequentially paced (AVP) for 2 hours or sham-operated. STCM was evaluated with ECG and vectorcardiogram (VCG), and subepicardial biopsies were taken at 5 to 120 minutes and investigated for CREB. LTCM was studied in dogs paced for 3 weeks and in sham controls. At 3 weeks the heart was excised, biopsies obtained, and CRE binding tested. STCM induction occurred in AVP dogs but not in sham or AVP dogs treated with saralasin or nifedipine. Nuclear CREB was significantly decreased at 2 hours in the AVP no-drug group only. LTCM dogs manifested reduced binding of nuclear proteins to CRE, and CRE binding activity in the promoter region of Kv4.3. In conclusion, there is an association between STCM induction and decreased nuclear CREB that is angiotensin-modulated and calcium-dependent. Moreover, the decreased CRE binding after 3 weeks of AVP combined with CRE binding activity in the Kv4.3 promoter can explain the Kv4.3 mRNA and Ito downregulation that characterize LTCM.

The effect of maternal cocaine exposure on neonatal rat cardiac function

Fetal cocaine exposure has been associated with a variety of cardiovascular dysfunctions in humans. We treated pregnant rats with either saline or cocaine at 60 mg/kg by gastric lavage for the entire gestational period and for 14 days after parturition. We then performed high-frequency transthoracic echocardiography to determine whether cocaine exposure affected neonatal cardiac contractile function in vivo in 7- and 14-day-old neonatal rats. All studies were performed in the unsedated, conscious state. Heart rate (HR) and systolic function, expressed as fractional area of change at the midpapillary muscle level, were calculated from two-dimensional images. Resting HR was faster in the cocaine-exposed group at both ages, but baseline contractile function was not different between control (CTL) and cocaine-exposed (COC) neonatal rats. Dobutamine induced a significant increase in HR in all groups at only the largest dose tested (Day 7 CTL HR increased from 438 +/- 3 bpm to 462 +/- 10 bpm; Day 7 COC HR increased from 466 +/- 3 bpm to 493 +/- 7 bpm; Day 14 CTL HR increased from 443 +/- 4 bpm to 487 +/- 4 bpm; Day 14 COC HR increased from 477 +/- 4 bpm to 501 +/- 5 bpm). Dobutamine elicited a significant increase in contractile response at both Day 7 (from 76.6% +/- 0.6% to 81.5% +/- 0.7%) and Day 14 in CTL (from 78.2% +/- 0.7% to 81.9% +/- 0.7%), but not in COC, animals (from 76.7% +/- 0.8% to 78.9% +/- 0.8% at Day 7 and from 76.8% +/- 1.1% to 79.3% +/- 0.8% at Day 14). Epinephrine induced a significant increase in contractile response in CTL, but not in COC, rats at Day 7 and had no effect on fractional area of change at 14 days of age in either CTL or COC animals. Our results indicate that perinatal cocaine exposure does not modify resting contractile function but attenuates the contractile response to beta-adrenoceptor stimulation in the neonatal rat. These results suggest that perinatal cocaine exposure may lead to decreased responsiveness to inotropic drugs during the early neonatal period.

Perinatal cocaine exposure stimulates the expression and activation of CREB in the neonatal rat heart

cAMP response binding protein (CREB) is a transcriptional factor known to regulate gene expression. Phosphorylation of CREB at serine 133 is necessary for CREB activation, and quantification of phospho-CREB (p-CREB) expression is an index of CREB activation. Because CREB expression and activation in specific brain regions are modified after chronic cocaine administration, we sought to determine whether chronic perinatal cocaine exposure affects the expression of CREB and p-CREB in the postnatal rat heart. Pregnant rats were treated daily with saline (control) or cocaine at 20 mg/kg (C20) or 60 mg/kg (C60) by intragastric administration throughout gestation. The expression of total CREB and p-CREB was quantified in nuclear extracts isolated from 1- and 7-d-old neonatal rat hearts. Cardiac nuclear p-CREB was increased in the C20 and C60 groups on d 1 and 7 of age compared with their respective age-matched control groups. The increase in p-CREB expression corresponded to an increase in cAMP response element binding activity. We also assayed nuclear protein kinase A activity, which was up-regulated in d 1 animals with prenatal cocaine exposure, but was comparable in all groups at d 7. Our results suggest that perinatal cocaine exposure stimulates CREB activation in the neonatal heart, and it may be mediated by different mechanisms at d 1 and d 7. The changes in myocardial CREB activation induced by perinatal cocaine exposure are likely to result in modified gene expression in the neonatal heart that may account for the cardiac dysfunction reported in human neonates born to cocaine-abusing mothers.

Sex-based differences in serum cardiac troponin I, a specific marker for myocardial injury, after cardiac surgery

BACKGROUND

Prevalence and causes of sex-based differences in morbidity and mortality secondary to cardiovascular disease remain controversial. Cardiac troponin I (cTnI) is a sensitive and specific marker for myocardial injury. Serial cTnI measurements have been used to identify perioperative myocardial cell injury.

OBJECTIVE

To determine whether sex influences the extent of myocardial injury during cardiac surgery, we measured perioperative cTnI in male and female patients.

DESIGN

A total of 17 male and 17 female patients were prospectively studied in an age- and case-matched manner. Arterial cTnI were obtained preinduction, 30 mins after the application of the aortic cross-clamp, at arrival to the intensive care unit, and on postoperative day 1.

SETTING

Tertiary cardiac surgery center at a major teaching hospital.

RESULTS

There was no difference between men and women in body mass index (kg/m2), duration of cardiopulmonary bypass, and aortic cross-clamp times. Preoperative cTnI measurements were similar in men (0.24 +/- 0.15 ng/mL) and women (0.25 +/- 0.13 ng/mL, mean +/- sem). The maximum serum cTnI occurred on postoperative day 1 in all patients, and it was 3-fold higher in men (18.5 +/- 5.7 ng/mL) compared with women (6.4 +/- 1.0 ng/mL).

CONCLUSIONS

Men had markedly higher serum cTnI compared with women, although they were case matched with respect to age and cardiac risk factors. Our results may suggest there may be sex-related differences in the myocardial response to ischemia and reperfusion injury or intrinsic differences between the male and female myocardium.

Despite in vitro increase in cyclic guanosine monophosphate concentrations, intracarotid nitroprusside fails to augment cerebral blood flow of healthy baboons

BACKGROUND

During cerebral angiography, intracarotid infusion of sodium nitroprusside (SNP), an endothelium-independent nitric oxide donor, fails to increase cerebral blood flow (CBF) of human subjects. A confounding effect of intracranial pathology or that of radiocontrast could not be ruled out in these experiments. The authors hypothesized that, if nitric oxide was a significant regulator of CBF of primates, then intracarotid SNP will augment CBF of baboons.

METHODS

In studies, CBF (intraarterial (133)Xe technique) was measured in healthy baboons during isoflurane anesthesia at (1) baseline and during (2) induced hypertension with intravenous phenylephrine, (3) concurrent infusions of intravenous phenylephrine and intracarotid SNP, and (4) intracarotid verapamil (positive control drug). In studies, the authors measured tissue cyclic guanosine monophosphate (cGMP) by radioimmunoassay after incubating vascular rings obtained from freshly killed baboons (1) with increasing concentrations of SNP and (2) after SNP exposure following preincubation with the radiocontrast agent, iohexhol.

RESULTS

In the studies, coinfusion of intravenous phenylephrine and intracarotid SNP did not increase CBF. However, intracarotid verapamil significantly increased CBF (from 26 +/- 7 to 43 +/- 11 ml x 100 g(-1) x min(-1); P < 0.0001) without a change in mean arterial pressure. In the studies, incubation of intracranial arterial rings in SNP resulted in dose-dependent increases in cGMP concentrations. A similar increase in cGMP content was evident despite iohexhol preincubation.

CONCLUSIONS

Collectively, these results suggest that, in healthy baboons, intracarotid SNP does not decrease arteriolar resistance, although SNP could affect proximal arterial tone, as demonstrated by the increase in cGMP content of these vessels.

Expression of adenylyl cyclase V/VI mRNA and protein is upregulated in cyanotic infant human myocardium

We have previously demonstrated that both basal and isoproterenol-stimulated activities of myocardial adenylyl cyclase were greater in cyanotic patients with tetralogy of Fallet (TOF) than those in acyanotic patients. However, it was not determined whether increased enzyme activity was related to a similar increase in adenylyl cyclase protein and mRNA expression. In the current study, we examined the mRNA and protein expression of cardiac adenylyl cyclase, types V and VI, in cyanotic and acyanotic patients with TOF. Ribonuclease protection assays and immunoblotting were performed on myocardial specimens obtained from cyanotic patients with TOF and acyanotic patients with TOF or ventricular septal defect. We demonstrated that in both cyanotic and acyanotic patients, there was more type V adenylyl cyclase mRNA than type VI. Types V and VI cardiac adenylyl cyclase mRNA were significantly increased in myocardium of the cyanotic group compared to the acyanotic group. Protein expression of both V and VI adenylyl cyclases was correspondingly upregulated in cyanotic patients compared to acyanotic patients. Our results indicate that gene and protein expression of cardiac adenylyl cyclases, types V and VI, is increased in the cyanotic myocardium. These results suggest that chronic hypoxemia may regulate the expression of adenylyl cyclase enzymes.

Incidence of atrial fibrillation after mild or moderate hypothermic cardiopulmonary bypass

OBJECTIVES

Atrial fibrillation remains a significant source of morbidity after coronary artery bypass grafting (CABG). Whether cardiopulmonary bypass (CPB) temperature influences the occurrence of postoperative atrial fibrillation in CABG patients has not been specifically examined. In the present study, we reviewed postoperative data from patients who were prospectively randomized to mild or moderate hypothermic CPB for elective CABG to determine the incidence of postoperative atrial fibrillation.

DESIGN

Randomized, single center, observational study.

SETTING

Tertiary university medical center.

PATIENTS

Adults undergoing elective CABG surgery.

INTERVENTIONS

Enrolled patients were prospectively randomized to mild (34 degrees C [93.2 degrees F]) or moderate (28 degrees C [82.4 degrees F]) hypothermic CPB.

MEASUREMENTS AND MAIN RESULTS

The incidence of postoperative atrial fibrillation was determined by review of ICU and hospital records. There was a significantly higher incidence of atrial fibrillation in the moderate compared with the mild hypothermic CPB group. Patients who had postoperative atrial fibrillation were significantly older than those without atrial fibrillation. Furthermore, a significant increase in the relative risk of developing postoperative atrial fibrillation was found for both age and CPB temperature.

CONCLUSIONS

Our results indicate that the temperature of systemic cooling during CPB is an important factor in the development of atrial fibrillation after CABG surgery. In addition, this study confirms that increasing age is a significant determinant of postoperative atrial fibrillation.