An Assessment of the Effects of General Anesthetics on Developing Brain Structure and Neurocognitive Function

A Retrospective Analysis of the Utility of Head Computed Tomography and/or Magnetic Resonance Imaging in the Management of Benign Macrocrania

OBJECTIVE

To assess whether computed tomography (CT), magnetic resonance imaging (MRI), and neurosurgical evaluations altered the diagnosis or management of children diagnosed with benign macrocrania of infancy by ultrasonography (US).

STUDY DESIGN

We queried our radiology database to identify patients diagnosed with benign macrocrania of infancy by US between 2006 and 2013. Medical records of those with follow-up CT/MRI were reviewed to determine clinical/neurologic status and whether or not CT/MRI imaging resulted in diagnosis of communicating hydrocephalus or required neurosurgical intervention.

RESULTS

Patients with benign macrocrania of infancy (n = 466) were identified (mean age at diagnosis: 6.5 months). Eighty-four patients (18.0%) received subsequent head CT/MRI; of these, 10 patients had neurologic abnormalities before 2 years of age, of which 3 had significant findings on MRI (temporal lobe white matter changes, dysmorphic ventricles, thinned corpus callosum). One patient without neurologic abnormalities had nonspecific white matter signal abnormality (stable over 6 months) but no change in management. None required neurosurgical intervention. Another 9/84 patients had incidental findings including Chiari I (3), small subdural bleeds (2), arachnoid cyst (1), small cavernous malformation (1), frontal bone dermoid (1), and a linear parietal bone fracture after a fall (1).

CONCLUSIONS

Children diagnosed with benign macrocrania of infancy on US without focal neurologic findings do not require subsequent brain CT/MRI or neurosurgical evaluation. Decreasing unnecessary imaging would decrease costs, minimize radiation and sedation exposures, and increase clinic availability of neurology and neurosurgery specialists.

Exploring the Pharmacokinetic Profile of Remifentanil in Mid-Trimester Gestations Undergoing Fetal Intervention Procedures

Background: Indications for surgery during pregnancy have increased. Specifically fetal interventions have increased from conditions that were considered lethal like twin-twin transfusion syndrome and severe fetal anemia to non-lethal conditions like myelomeningocele. The optimal anesthetic agent for in utero surgery is yet to be determined. Success of the procedure is often dictated by the efficacy of the anesthetic to immobilize the fetus without over-sedating mom. Remifentanil is used as preferred agent due to its short half-life however pharmacokinetics in pregnancy is unknown.

Objective: To determine the pharmacokinetic parameters of remifentanil in a mid-trimester pregnant patient population undergoing fetal intervention.

Study Design: A validated liquid chromatography assay with ultraviolet absorbance was employed to estimate maternal serum remifentanil levels. Blood samples were obtained at baseline and at selected time points: 5, 15, 30, 45, 60 min after the beginning of the remifentanil infusion and at 15, 30, and 60 min post end of infusion.

Results: Ten pregnant patients were enrolled in the study however only eight patients had sampling obtained at all time points. The mean gestational age was 22.2 (±2.7) weeks, maternal age was 27.8 (±5.1) years and body mass index was 29.6 (±6.3). After receiving a continuous infusion of remifentanil, mean total dose was 975.3 μg, C_min was 2.0 ng/mL and C_max was 8.4 ng/mL. A two-compartment model best described the plasma remifentanil data. Mean pharmacokinetic parameters were: volume of distribution (Vd_c) = 124.6 L (16.2–530.8 L), maternal remifentanil total clearance (Cl_t) = 170.7 L/h (17.7–486.9 L/h), and half-life (t_½) = 0.6 h (0.2–0.9 h). The maternal remifentanil area under the curve (AUC) ranged from 2.7 to 21.7 μg/L^*h. The mean alpha-acidic glycoprotein was 124.8 mg/dL (81.3–149.8).

Conclusion: The pharmacokinetic profile of remifentanil in pregnant women is similar to previously reported general population profiles. This data did provide potential rationale for the clinical observations why when remifentanil is dosed based on non-pregnant guidelines, it did not uniformly provide adequate fetal immobilization as per anecdotal perception of operating fetal surgeons. These findings are important for the development of further clinical studies to optimize dosing for surgery during pregnancy including the estimation of placental transfer and total fetal exposure.

Neuroprotection and neurotoxicity in the developing brain: an update on the effects of dexmedetomidine and xenon

Growing and consistent preclinical evidence, combined with early clinical epidemiological observations, suggest potentially neurotoxic effects of commonly used anesthetic agents in the developing brain. This has prompted the FDA to issue a safety warning for all sedatives and anesthetics approved for use in children under three years of age. Recent studies have identified dexmedetomidine, the potent α2-adrenoceptor agonist, and xenon, the noble gas, as effective anesthetic adjuvants that are both less neurotoxic to the developing brain, and also possess neuroprotective properties in neonatal and other settings of acute ongoing neurologic injury. Dexmedetomidine and xenon are effective anesthetic adjuvants that appear to be less neurotoxic than other existing agents and have the potential to be neuroprotective in the neonatal and pediatric settings. Although results from recent clinical trials and case reports have indicated the neuroprotective potential of xenon and dexmedetomidine, additional randomized clinical trials corroborating these studies are necessary. By reviewing both the existing preclinical and clinical evidence on the neuroprotective effects of dexmedetomidine and xenon, we hope to provide insight into the potential clinical efficacy of these agents in the management of pediatric surgical patients.

Influence of General Anesthesia on Impulsivity and Learning Ability-Experimental Study

Objective: To investigate the effect of anesthesia on rats’ ability of learning and over their impulsivity.

Material and Methods: We studied eight Wistar adult male rats, test and drug naive subjects. Animals were separated in two groups, group A and B with four members each. Group A included the anesthetized animals. The combination of ketamine, xylazine and piplophen in 2ml/kg body weight dosage was used and testing was done 24 hours after anesthesia. Group B was taken as control. The study was conducted using the ”Delay discounting” apparatus. Experiments assessing impulsive behavior were conducted using automated operant chambers, equipped with two nose-poke holes (holes where pellets of food were released). Rat’s answer was considered touching the nose-poke hole. One answer was rewarded with pellets of food of 45 mg each (small reward), while another hole released five pellets of 45 mg each (high reward). Both types of rewards were presented immediately after rat’s answer and were followed for a period of 25 seconds timeout. During the training phase, rats were placed in operant chambers 30 minutes per day, 5 consecutive days. The growing percent of preference for greater reward indicates learning. For the testing phase the procedure was similar, but a delay was introduced before the release of the big reward. During this phase, the preference for higher reward was indicative for non-impulsive behaviour.

Results: The results didn’t show significant statistically differences between the two groups.

Conclusions: Anesthesia had no effect on learning ability nor on impulsivity.

Early childhood exposure to short periods of sevoflurane is not associated with later, lasting cognitive deficits

BACKGROUND

A detrimental effect of commonly used anesthetics on the neurodevelopmental and behavioral parameters has long been shown in young animals subjected to early childhood anesthesia. Epidemiologic studies suggest the possibility of a modestly elevated risk of adverse neurodevelopmental outcomes in children exposed to anesthesia during early childhood. However, these results are still preliminary and inconclusive.

AIM

To further elucidate the probability of occurrence of such adverse outcomes, we evaluated cognitive performance of children who underwent general anesthesia early in their childhood.

METHOD

One hundred and fifteen children aged 5-16 years with established glaucoma were included in the study. Of these, 68 children had a history of at least one general anesthesia with sevoflurane before age 3. Phonemic and semantic verbal fluency, and forward and backward digit span tests were performed to evaluate cognitive function in the study subjects.

RESULTS

The two-way anova revealed that all these variables showed significant changes in various age groups, but they were comparable among subjects with no, single, or multiple childhood anesthesia.

CONCLUSION

It can be concluded that brief periods of anesthesia with single anesthetic sevoflurane may be safe for children under age 3.

Neurodevelopmental Assessment in Kindergarten in Children Exposed to General Anesthesia before the Age of 4 Years: A Retrospective Matched Cohort Study

BACKGROUND

Animal studies demonstrate general anesthetic (GA) toxicity in the developing brain. Clinical reports raise concern, but the risk of GA exposure to neurodevelopment in children remains uncertain.

METHODS

The authors undertook a retrospective matched cohort study comparing children less than 4 yr of age exposed to GA to those with no GA exposure. The authors used the Early Development Instrument (EDI), a 104-component questionnaire, encompassing five developmental domains, completed in kindergarten as the outcome measure. Mixed-effect logistic regression models generated EDI estimates for single versus multiple GA exposure and compared both single and multiple exposures by the age of 0 to 2 or 2 to 4 yr. Known sociodemographic and physical confounders were incorporated as covariates in the models.

RESULTS

A total of 18,056 children were studied: 3,850 exposed to a single GA and 620 exposed to two or more GA, who were matched to 13,586 nonexposed children. In children less than 2 yr of age, there was no independent association between single or multiple GA exposure and EDI results. Paradoxically, single exposure between 2 and 4 yr of age was associated with deficits, most significant for communication/general knowledge (estimate, -0.7; 95% CI, -0.93 to -0.47; P < 0.0001) and language/cognition (estimate, -0.34; 95% CI, -0.52 to -0.16; P < 0.0001) domains. Multiple GA exposure at the age of 2 to 4 yr did not confer greater risk than single GA exposure.

CONCLUSIONS

These findings refute the assumption that the earlier the GA exposure in children, the greater the likelihood of long-term neurocognitive risk. The authors cannot confirm an association between multiple GA exposure and increased risk of neurocognitive impairment, increasing the probability of confounding to explain the results.

The decrease of NMDAR subunit expression and NMDAR EPSC in hippocampus by neonatal exposure to desflurane in mice

Desflurane is one of the third generation inhaled anesthetics and can be used in obstetric and pediatric medicine. However, effects of exposure to desflurane on neonatal brain are largely unknown. In this work, 6-day-old C57BL/6J mice were exposed to 1MAC or 1.5MAC desflurane for 2h. When the mice were 28-day-old, the open-field, spontaneous alternation Y-maze and fear conditioning tests were performed to evaluate general activity, working memory and long term memory, respectively. Levels of NMDAR subunits NR1, NR2A, and NR2B expression in hippocampus were evaluated by western blot. NMDAR-mediated excitatory postsynaptic current (EPSC) in mouse hippocampal slice was recorded by whole-cell patch clamp record. Mice exposed to 1.5MAC desflurane had significantly impaired working memory and fear conditioning memory. The protein expression of NMDAR subunits (NR1, NR2B) and NMDAR-mediated EPSC in hippocampus were significantly decreased. However no significant difference was detected between mice exposed to 1.0MAC desflurane and control mice. In conclusion, in an animal model, 6-day-old mice exposed to 1.5MAC desflurane have significant impairments in working memory and contextual fear memory at postnatal day 28, and the decrease of NMDAR subunits expression and NMDAR EPSC in hippocampus may be involved in this process.

Emergency Neurological Life Support: Airway, Ventilation, and Sedation

Airway management and ventilation are central to the resuscitation of the neurologically ill. These patients often have evolving processes that threaten the airway and adequate ventilation. Furthermore, intubation, ventilation, and sedative choices directly affect brain perfusion. Therefore, airway, ventilation, and sedation was chosen as an emergency neurological life support protocol. Topics include airway management, when and how to intubate with special attention to hemodynamics and preservation of cerebral blood flow, mechanical ventilation settings, and the use of sedative agents based on the patient's neurological status.

Early-life single-episode sevoflurane exposure impairs social behavior and cognition later in life

BACKGROUND

Single-episode anesthetic exposure is the most prevalent surgery-related incidence among young children in the United States. Although numerous studies have used animals to model the effects of neonatal anesthetics on behavioral changes later on in life, our understanding of the functional consequences to the developing brain in a comprehensive and clinically relevant manner is unclear.

METHODS

The volatile anesthetic, sevoflurane (sevo) was administered to C57BL6 postnatal day 7 (P7) mice in a 40% oxygen and 60% nitrogen gas mixture. In order to examine the effects of sevo alone on the developing brain in a clinically relevant manner, mice were exposed to an average of 2.38 ± 0.11% sevo for 2 h. No sevo (control) mice were treated in an identical manner without sevo exposure. Mice were examined for cognition and neuropsychiatric-like behavioral changes at 1-5 months of age.

RESULTS

Using the active place avoidance (APA) test and the novel object recognition (NOR) test, we demonstrated that P7 sevo-treated mice showed a deficit in learning and memory both during periadolescence and adulthood. We then employed a battery of neuropsychiatric-like behavioral tests to examine social interaction, communication, and repetitive behavior. Interestingly, compared to the no-sevo-treated group, sevo-treated mice showed significant reductions in the time interacting with a novel mouse (push-crawl and following), time and interaction in a chamber with a novel mouse, and time sniffing a novel social odor.

CONCLUSIONS

Our study established that single-episode, 2-h sevo treatment during early life impairs cognition later on in life. With this approach, we also observed neuropsychiatric-like behavior changes such as social interaction deficits in the sevo-treated mice. This study elucidated the effects of a clinically relevant single-episode sevo application, given during the neonatal period, on neurodevelopmental behavioral changes later on in life.

Eyeblink classical conditioning and BOLD fMRI of anesthesia-induced changes in the developing brain

Millions of children undergo general anesthesia each year in the USA alone, and a growing body of literature from animals and humans suggests that exposure to anesthesia at an early age can impact neuronal development, leading to learning and memory impairments later in childhood. Although a number of studies have reported behavioral and structural effects of anesthesia exposure during infancy, the functional manifestation of these changes has not been previous examined. In this study we used BOLD fMRI to measure the functional response to stimulation in the whisker barrel cortex of awake rabbits before and after learning a trace eyeblink classical conditioning paradigm. The functional changes, in terms of activated volume and time course, in rabbits exposed to isoflurane anesthesia during infancy was compared to unanesthetized controls when both groups reached young adulthood. Our findings show that whereas both groups exhibited decreased BOLD response duration after learning, the anesthesia-exposed group also showed a decrease in BOLD response volume in the whisker barrel cortex, particularly in the deeper infragranular layer. These results suggest that anesthesia exposure during infancy may affect the intracortical processes that mediate learning-related plasticity.

Multiple exposure to general anesthesia in pediatric patients and the development of specific learning disorder: a systematic review protocol

REVIEW QUESTION/OBJECTIVE

The objective of this systematic review is to identify the association between multiple exposure to general anesthesia and the development of specific learning disorder in pediatric patients aged two years and younger.

From Drug-Induced Developmental Neuroapoptosis to Pediatric Anesthetic Neurotoxicity-Where Are We Now?

The fetal and neonatal periods are critical and sensitive periods for neurodevelopment, and involve rapid brain growth in addition to natural programmed cell death (i.e., apoptosis) and synaptic pruning. Apoptosis is an important process for neurodevelopment, preventing redundant, faulty, or unused neurons from cluttering the developing brain. However, animal studies have shown massive neuronal cell death by apoptosis can also be caused by exposure to several classes of drugs, namely gamma-aminobutyric acid (GABA) agonists and N-methyl-d-aspartate (NMDA) antagonists that are commonly used in pediatric anesthesia. This form of neurotoxic insult could cause a major disruption in brain development with the potential to permanently shape behavior and cognitive ability. Evidence does suggest that psychoactive drugs alter neurodevelopment and synaptic plasticity in the animal brain, which, in the human brain, may translate to permanent neurodevelopmental changes associated with long-term intellectual disability. This paper reviews the seminal animal research on drug-induced developmental apoptosis and the subsequent clinical studies that have been conducted thus far. In humans, there is growing evidence that suggests anesthetics have the potential to harm the developing brain, but the long-term outcome is not definitive and causality has not been determined. The consensus is that there is more work to be done using both animal models and human clinical studies.

Neuroprotective effects of caffeic acid phenethyl ester against sevoflurane‑induced neuronal degeneration in the hippocampus of neonatal rats involve MAPK and PI3K/Akt signaling pathways

Millions of infants and children are exposed to anesthesia every year during medical care. Sevoflurane is a volatile anesthetic that is frequently used for pediatric anesthesia. However, previous reports have suggested that the administration of sevoflurane promotes neurodegeneration, raising concerns regarding the safety of its usage. The present study aimed to investigate caffeic acid phenethyl ester (CAPE) and its protective effect against sevoflurane‑induced neurotoxicity in neonatal rats. Rat pups were administered with CAPE at 10, 20 or 40 mg/kg body weight from postnatal day 1 (P1) to P15. The P7 rats were exposed to sevoflurane (2.9%) for 6 h. Control group rats received no sevoflurane or CAPE. Neuronal apoptosis was determined by terminal deoxynucleotidyl transferase dUTP nick‑end labeling assay. The expression levels of caspases (caspase‑3, ‑8 and ‑9), apoptotic pathway proteins [Bcl‑2‑associated X protein (Bax), B cell CCL/lymphoma 2 (Bcl‑2), Bcl‑2‑like 1 (Bcl‑xL), Bcl‑2‑associated agonist of cell death (Bad) and phosphorylated (p)‑Bad], mitogen‑activated protein kinases (MAPK) signaling pathway proteins [c‑Jun N‑terminal kinase (JNK), p‑JNK, extracellular signal‑regulated kinase (ERK)1/2, p‑ERK1/2, p38, p‑p38 and p‑c‑Jun] and the phosphoinositide 3‑kinase (PI3K)/Akt cascade were evaluated by western blotting following sevoflurane and CAPE treatment. In addition, the expression of cleaved caspase‑3 was analyzed by immunohistochemistry. CAPE significantly reduced sevoflurane‑induced apoptosis, downregulated the expression levels of caspases and pro‑apoptotic proteins (Bax and Bad) and elevated the expression levels of Bcl‑2 and Bcl‑xL when compared with sevoflurane treatment. Furthermore, CAPE appeared to modify the expression levels of MAPKs and activate the PI3K/Akt signaling pathway. Thus, the present study demonstrated that CAPE effectively inhibited sevoflurane‑induced neuroapoptosis by modulating the expression and phosphorylation of apoptotic pathway proteins and MAPKs, and by regulating the PI3K/Akt pathway.

Effect of Day and Night Desflurane Anaesthesia on Melatonin Levels in Rats

OBJECTIVE

The aim of this study is to investigate the effect of day and night administration of desflurane anaesthesia on melatonin levels in rats.

METHODS

Twenty-four 15-day-old rats were included in the study and were divided into four groups. The rats were anaesthetised between 19:00-01:00 (night group) and 07:00-13:00 (day group) with 5.7% desflurane concentration in 6 L min^-1 100% oxygen. 6 L min^-1 oxygen was administered to the control groups. At the end of 6 h of anaesthesia, blood samples were taken, and rats were sacrificed. Blood samples were centrifuged and melatonin levels from plasma samples were measured with radioimmunoassay.

RESULTS

There was a statistically significant difference between the groups (p=0.007). Between group day control and group night control there was a statistically significant difference (p=0.042). Further, there was a significant difference between group day control and night desfluran as well (p=0.024). We could not find any difference between other groups.

CONCLUSION

This study showed that 6 hours of 5.7% desflurane anaesthesia during day and night hours did not significantly change melatonin levels.

Effectiveness of sugammadex for cerebral ischemia/reperfusion injury

Cerebral ischemia may cause permanent brain damage and behavioral dysfunction. The efficacy and mechanisms of pharmacological treatments administered immediately after cerebral damage are not fully known. Sugammadex is a licensed medication. As other cyclodextrins have not passed the necessary phase tests, trade preparations are not available, whereas sugammadex is frequently used in clinical anesthetic practice. Previous studies have not clearly described the effects of the cyclodextrin family on cerebral ischemia/reperfusion (I/R) damage. The aim of this study was to determine whether sugammadex had a neuroprotective effect against transient global cerebral ischemia. Animals were assigned to control, sham-operated, S 16 and S 100 groups. Transient global cerebral ischemia was induced by 10-minute occlusion of the bilateral common carotid artery, followed by 24-hour reperfusion. At the end of the experiment, neurological behavior scoring was performed on the rats, followed by evaluation of histomorphological and biochemical measurements. Sugammadex 16 mg/kg and 100 mg/kg improved neurological outcome, which was associated with reductions in both histological and neurological scores. The hippocampus TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) and caspase results in the S 16 and S 100 treatment groups were significantly lower than those of the I/R group. Neurological scores in the treated groups were significantly higher than those of the I/R group. The study showed that treatment with 16 mg/kg and 100 mg/kg sugammadex had a neuroprotective effect in a transient global cerebral I/R rat model. However, 100 mg/kg sugammadex was more neuroprotective in rats.

Propofol exposure during late stages of pregnancy impairs learning and memory in rat offspring via the BDNF-TrkB signalling pathway

The brain‐derived neurotrophic factor (BDNF)‐tyrosine kinase B (TrkB) (BDNF‐TrkB) signalling pathway plays a crucial role in regulating learning and memory. Synaptophysin provides the structural basis for synaptic plasticity and depends on BDNF processing and subsequent TrkB signalling. Our previous studies demonstrated that maternal exposure to propofol during late stages of pregnancy impaired learning and memory in rat offspring. The purpose of this study is to investigate whether the BDNF‐TrkB signalling pathway is involved in propofol‐induced learning and memory impairments. Propofol was intravenously infused into pregnant rats for 4 hrs on gestational day 18 (E18). Thirty days after birth, learning and memory of offspring was assessed by the Morris water maze (MWM) test. After the MWM test, BDNF and TrkB transcript and protein levels were measured in rat offspring hippocampus tissues using real‐time PCR (RT‐PCR) and immunohistochemistry (IHC), respectively. The levels of phosphorylated‐TrkB (phospho‐TrkB) and synaptophysin were measured by western blot. It was discovered that maternal exposure to propofol on day E18 impaired spatial learning and memory of rat offspring, decreased mRNA and protein levels of BDNF and TrkB, and decreased the levels of both phospho‐TrkB and synaptophysin in the hippocampus. Furthermore, the TrkB agonist 7,8‐dihydroxyflavone (7,8‐DHF) reversed all of the observed changes. Treatment with 7,8‐DHF had no significant effects on the offspring that were not exposed to propofol. The results herein indicate that maternal exposure to propofol during the late stages of pregnancy impairs spatial learning and memory of offspring by disturbing the BDNF‐TrkB signalling pathway. The TrkB agonist 7,8‐DHF might be a potential therapy for learning and memory impairments induced by maternal propofol exposure.

Apert syndrome: Surgical outcomes and perspectives

PURPOSE

Apert syndrome is a rare congenital malformation with severe craniofacial anomalies. The aim of this study was to review the outcomes of craniofacial and neurosurgical interventions in Apert syndrome patients treated at a single institution.

MATERIALS AND METHODS

A retrospective review of all patient records with a diagnosis of Apert syndrome assessed and managed in the Australian Craniofacial Unit (ACFU) from 1985 to 2013 was conducted.

RESULTS

A total of 94 patients were identified, and 130 transcranial procedures were performed. Of the patients, 83 underwent a fronto-orbital advancement (FOA) as their primary procedure, and 18 patients also underwent a posterior vault procedure. Twenty patients underwent a fronto-facial monobloc advancement. Overall, 70% of patients underwent at least 2 transcranial procedures. Shunts were inserted in 2 patients preoperatively and in 5 patients postoperatively for cerebrospinal fluid (CSF) leaks or acute hydrocephalus. Re-do FOAs were performed in 8 patients. Patients who underwent an FOA at the age of more than 18 months had no recurrence of raised intracranial pressure (ICP). Of 18 patients who also underwent a posterior vault procedure, 1 patient had recurrence of raised ICP. Midfacial surgery was performed early if there was evidence of obstructive sleep apnoea (OSA), but delayed midfacial surgery was preferred. Complications were reported in 18% of procedures. The most common complications were CSF leaks and acute hydrocephalus.

CONCLUSION

Shunting is rarely required in Apert syndrome patients, confirming a predominantly nonprogressive ventriculomegaly. FOA appears to be a more stable procedure when performed at an age of more than 18 months. Undergoing a posterior vault procedure may reduce the risk of recurrent raised ICP and lead to fewer transcranial procedures needed in childhood. Midfacial surgery should be delayed until adolescence where there is no evidence of OSA, psychological disturbance, or complications of exorbitism. Complications are rare when these patients are treated by an experienced craniofacial team.

rno-miR-665 targets BCL2L1 (Bcl-xl) and increases vulnerability to propofol in developing astrocytes

Propofol exerts a cytotoxic influence over immature neurocytes. Our previous study revealed that clinically relevant doses of propofol accelerated apoptosis of primary cultured astrocytes of developing rodent brains via rno-miR-665 regulation. However, the role of rno-miR-665 during the growth spurt of neonatal rodent brains in vivo is still uncertain. Post-natal day 7 (P7) rats received a single injection of propofol 30 mg/kg intraperitoneally (i.p.), and neuroapoptosis of hippocampal astrocytes was analyzed by immunofluorescence and scanning electron microscopy. The differential expression of rno-miR-665, BCL2L1 (Bcl-xl), and cleaved caspase 3 (CC3) was surveyed by qRT-PCR and western blotting. In addition, the utility of A-1155463, a highly potent and BCL2L1-selective antagonist, was aimed to assess the contribution of BCL2L1 for neuroglial survival. Following the intraventricular injection of lentivirus rno-miR-665, neuroprotection was detected by 5-point scale measurement. The single dose of propofol 30 mg/kg triggered dose-dependent apoptosis of developing hippocampal astrocytes. Meanwhile, propofol triggered both rno-miR-665 and CC3, and depressed BCL2L1, which was predicted as one target gene of rno-miR-665. Combination treatment with A-1155463 and propofol induced lower mRNA and protein levels of BCL2L1 and more CC3 activation than propofol treatment alone in vivo. The lentivirus-mediated knockdown of rno-miR-665 elevated BCL2L1 and attenuated CC3 levels, whereas up-regulation of rno-miR-665 suppressed BCL2L1 and induced CC3 expression in vivo. More importantly, rno-miR-665 antagomir infusion improved neurological outcomes of pups receiving propofol during the brain growth spurt. Rno-miR-665, providing a potential target for alternative therapeutics for pediatric anesthesia, is susceptible to propofol by negatively targeting antiapoptotic BCL2L1. Relatively little is known about the association between exposure of astrocytes to brief propofol anaesthesia and risk for impairment. Here, it revealed that propofol-related neurotoxicity of neonatal astrocytes was under rno-miR-665 regulation during the brain growth spurt. Rno-miR-665 might act as a clinically alternative therapeutic target for treatment of neurological disorders in peadiatric anesthesia or sedation with propofol in future.

Undescended testes: an update

PURPOSE OF REVIEW

This article summarizes the latest evidence on the risk factors, management and outcomes of undescended testes (UDTs).

RECENT FINDINGS

UDTs remain common, with increasing evidence that acquired UDT or the ascending testis syndrome should be considered part of the spectrum of this disease. Prompt diagnosis and early referral for surgical evaluation and treatment would seem most likely to result in an optimal functional and cosmetic outcome. Hormonal treatment, rather than orchidopexy, remains popular in some centers, despite a lack of good evidence to support its efficacy, although it may have an important adjunct role in optimizing fertility. Although often performed, ultrasound does not generally assist in the diagnosis and management of UDT, with enhanced education of primary care physicians more likely to facilitate early referral. The testis, rather than quiescent, appears biologically active in the male infant, with increasing evidence of an adverse impact on future spermatogenesis and fertility in men with a UDT.

SUMMARY

Male infants with a UDT should be diagnosed and referred early for surgical evaluation. It seems likely that the optimal timing for surgery should be before the boy's first birthday. There remains a need for high-quality, long-term outcomes data to guide optimal management.

The Fas Ligand/Fas Death Receptor Pathways Contribute to Propofol-Induced Apoptosis and Neuroinflammation in the Brain of Neonatal Rats

A number of experimental studies have reported that exposure to common, clinically used anesthetics induce extensive neuroapoptosis and cognitive impairment when applied to young rodents, up to 2 weeks old, in phase of rapid synaptogenesis. Propofol is the most used general anesthetic in clinical practice whose mechanisms of neurotoxicity on the developing brain remains to be examined in depth. This study investigated effects of different exposures to propofol anesthesia on Fas receptor and Fas ligand expressions, which mediate proapoptotic and proinflammation signaling in the brain. Propofol (20 mg/kg) was administered to 7-day-old rats in multiple doses sufficient to maintain 2-, 4- and 6-h duration of anesthesia. Animals were sacrificed at 0, 4, 16 and 24 h after termination of anesthesia. It was found that propofol anesthesia induced Fas/FasL and downstream caspase-8 expression more prominently in the thalamus than in the cortex. Opposite, Bcl-2 and caspase-9, markers of intrinsic pathway activation, were shown to be more influenced by propofol treatment in the cortex. Further, we have established upregulation of caspase-1 and IL-1β cytokine transcription as well as subsequent activation of microglia that is potentially associated with brain inflammation. Behavioral analyses revealed that P35 and P60 animals, neonatally exposed to propofol, had significantly higher motor activity during three consecutive days of testing in the open field, though formation of the intersession habituation was not prevented. This data, together with our previous results, contributes to elucidation of complex mechanisms of propofol toxicity in developing brain.

Erythropoietin diminishes isoflurane-induced apoptosis in rat frontal cortex

BACKGROUND

During the brain growth spurt, anesthetic drugs can cause cellular and behavioral changes in the developing brain. The aim of this study was to determine the neuroprotective effect of erythropoietin after isoflurane anesthesia in rat pups.

METHODS

A total of 42, 7-day-old Wistar rats were divided into three groups. Control group (GC; n = 14): Rats breathed 100% oxygen for 6 h; Isoflurane group (GI; n = 14): Rats were exposed to 1.5% isoflurane in 100% oxygen for 6 h; Isoflurane + erythropoietin group (GIE; n = 14): 1000 IU·kg(-1) (intraperitoneal; IP) Erythropoietin was administered after isoflurane anesthesia. Each group was divided into two groups for pathology and learning and memory tests. Silver, caspase-3, and fluoro-jade C staining were used for detecting apoptotic cells in frontal cortex, striatum, hippocampus, thalamus, and amygdala. Morris water maze was used to evaluate learning and memory.

RESULTS

There was a significant increase in apoptotic cell count after isoflurane anesthesia in the frontal cortex when compared with control group (29.0 ± 9.27 vs 3.28 ± 0.75 [P = 0.002], 20.85 ± 10.94 vs 2.0 ± 0.81 [P = 0.002] and 24.57 ± 10.4 vs 5.14 ± 0.69 [P = 0.024] with silver, caspase-3, and fluoro-jade C staining, respectively). The apoptotic cell count in the frontal cortex was significantly higher in GIE than GC with caspase-3 staining (9.14 ± 3.13 vs 2.0 ± 0.81, P = 0.002). The apoptotic cell count in GIE was significantly reduced in the frontal cortex when compared with GI (4.0 ± 0.81 vs 29.0 ± 9.27 [P = 0.002], 9.14 ± 3.13 vs 20.85 ± 10.94 [P = 0.04] and 4.0 ± 1.63 vs 24.57 ± 10.4 [P = 0.012] with silver, caspase-3, and fluoro-jade C staining, respectively).

CONCLUSIONS

A total of 1000 IU·kg(-1) IP erythropoietin diminished isoflurane-induced neuroapoptosis. Further experimental studies have to be planned to reveal the optimal dose and timing of erythropoietin before adaptation to clinical practice.

Effects of GABAA kinetics on cortical population activity: computational studies and physiological confirmations

Voltage-sensitive dye (VSD) imaging produces an unprecedented real-time and high-resolution mesoscopic signal to measure the cortical population activity. We have previously shown that the neuronal compartments contributions to the signal are dynamic and stimulus-dependent (Chemla S, Chavane F. Neuroimage 53: 420-438, 2010). Moreover, the VSD signal can also be strongly affected by the network state, such as in anesthetized vs. awake preparations. Here, we investigated the impact of the network state, through GABAA receptors modulation, on the VSD signal using a computational approach. We therefore systematically measured the effect of the GABAA-mediated inhibitory postsynaptic potentials (IPSPs) decay time constant (τG) on our modeled VSD response to an input stimulus of increasing strength. Our simulations suggest that τG strongly modulates the dynamics of the VSD signal, affecting the amplitude, input response function, and the transient balance of excitation and inhibition. We confirmed these predictions experimentally on awake and anesthetized monkeys, comparing VSD responses to drifting gratings stimuli of various contrasts. Lastly, one in vitro study has suggested that GABAA receptors may also be directly affected by the VSDs themselves (Mennerick S, Chisari M, Shu H, Taylor A, Vasek M, Eisenman L, Zorumski C. J Neurosci 30: 2871-2879, 2010). Our modeling approach suggests that the type of modulation described in this study would actually have a negligible influence on the population response. This study highlights that functional results acquired with different techniques and network states must be compared with caution. Biophysical models are proposed here as an adequate tool to delineate the domain of VSD data interpretation.

Xenon depresses aEEG background voltage activity whilst maintaining cardiovascular stability in sedated healthy newborn pigs

BACKGROUND

Changes in electroencephalography (EEG) voltage range are used to monitor the depth of anaesthesia, as well as predict outcome after hypoxia-ischaemia in neonates. Xenon is being investigated as a potential neuroprotectant after hypoxic-ischaemic brain injury, but the effect of Xenon on EEG parameters in children or neonates is not known. This study aimed to examine the effect of 50% inhaled Xenon on background amplitude-integrated EEG (aEEG) activity in sedated healthy newborn pigs.

METHODS

Five healthy newborn pigs, receiving intravenous fentanyl sedation, were ventilated for 24 h with 50%Xenon, 30%O2 and 20%N2 at normothermia. The upper and lower voltage-range of the aEEG was continuously monitored together with cardiovascular parameters throughout a 1 h baseline period with fentanyl sedation only, followed by 24 h of Xenon administration.

RESULTS

The median (IQR) upper and lower aEEG voltage during 1 h baseline was 48.0 μV (46.0-50.0) and 25.0 μV (23.0-26.0), respectively. The median (IQR) aEEG upper and lower voltage ranges were significantly depressed to 21.5 μV (20.0-26.5) and 12.0 μV (12.0-16.5) from 10 min after the onset of 50% Xenon administration (p=0.002). After the initial Xenon induced depression in background aEEG voltage, no further aEEG changes were seen over the following 24h of ventilation with 50% xenon under fentanyl sedation. Mean arterial blood pressure and heart rate remained stable.

CONCLUSION

Mean arterial blood pressure and heart rate were not significantly influenced by 24h Xenon ventilation. 50% Xenon rapidly depresses background aEEG voltage to a steady ~50% lower level in sedated healthy newborn pigs. Therefore, care must be taken when interpreting the background voltage in neonates also receiving Xenon.

Altered Mitochondrial Dynamics Contributes to Propofol-induced Cell Death in Human Stem Cell-derived Neurons

BACKGROUND

Studies in developing animals have shown that anesthetic agents can lead to neuronal cell death and learning disabilities when administered early in life. Development of human embryonic stem cell-derived neurons has provided a valuable tool for understanding the effects of anesthetics on developing human neurons. Unbalanced mitochondrial fusion and fission lead to various pathological conditions including neurodegeneration. The aim of this study was to dissect the role of mitochondrial dynamics in propofol-induced neurotoxicity.

METHODS

Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate in situ nick-end labeling staining was used to assess cell death in human embryonic stem cell-derived neurons. Mitochondrial fission was assessed using TOM20 staining and electron microscopy. Expression of mitochondrial fission-related proteins was assessed by Western blot, and confocal microscopy was used to assess opening time of the mitochondrial permeability transition pore (mPTP).

RESULTS

Exposure to 6 h of 20 μg/ml propofol increased cell death from 3.18 ± 0.17% in the control-treated group to 9.6 ± 0.95% and led to detrimental increases in mitochondrial fission (n = 5 coverslips per group) accompanied by increased expression of activated dynamin-related protein 1 and cyclin-dependent kinase 1, key proteins responsible for mitochondrial fission. Propofol exposure also induced earlier opening of the mPTP from 118.9 ± 3.1 s in the control-treated group to 73.3 ± 1.6 s. Pretreatment of the cells with mdivi-1, a mitochondrial fission blocker rescued the propofol-induced toxicity, mitochondrial fission, and mPTP opening time (n = 75 cells per group). Inhibiting cyclin-dependent kinase 1 attenuated the increase in cell death and fission and the increase in expression of activated dynamin-related protein 1.

CONCLUSION

These data demonstrate for the first time that propofol-induced neurotoxicity occurs through a mitochondrial fission/mPTP-mediated pathway.

Risk of autistic disorder after exposure to general anaesthesia and surgery: a nationwide, retrospective matched cohort study

BACKGROUND

Deficits of learning, memory and cognition have been observed in newborn animals exposed to general anaesthetics. However, conclusions from clinical studies conducted in humans to investigate the relationship between anaesthesia and neurodevelopmental disorders have been inconsistent. Autistic disorder is typically recognised earlier than other neurobehavioural disorders. Although certain genes apparently contribute to autistic disorder susceptibility, other factors such as perinatal insults and exposure to neurotoxic agents may play a crucial role in gene-environmental interaction.

OBJECTIVE

This study was designed to investigate the association of exposure to general anaesthesia/surgery with autistic disorder. We hypothesised that exposure to general anaesthesia and surgery before 2 years of age is associated with an increased risk of developing autistic disorder.

DESIGN

A retrospective matched-cohort study.

SETTING

A medical university. Data from the National Health Insurance Research Database of Taiwan from 2001 to 2010 were analysed.

PATIENTS

The birth cohort included 114,435 children, among whom 5197 were exposed to general anaesthesia and surgery before the age of 2 years. The 1 : 4 matched controls comprised 20,788 children.

MAIN OUTCOME MEASURES

The primary endpoint was the diagnosis of autistic disorder after the first exposure to general anaesthesia and surgery.

RESULTS

No differences were found in the incidence of autistic disorder between the exposed group (0.96%) and the unexposed controls (0.89%) (P = 0.62). Cox proportional regression showed that the hazard ratio of exposure to general anaesthesia and surgery was 0.93 [95% confidence interval (95% CI) 0.57 to 1.53] after adjusting for potential confounders. Age at first exposure did not influence the risk of autistic disorder. No relationship was found between the total number of exposures and the risk of autistic disorder.

CONCLUSION

Exposure to general anaesthesia and surgery before the age of 2 years age at first exposure and number of exposures were not associated with the development of autistic disorder.

Regional versus general anaesthesia for improved cognitive function after procedures other than cardiac surgery or neurosurgery in adult and paediatric patients

This is the protocol for a review and there is no abstract. The objectives are as follows: The objective of this review is to compare the effects of regional versus general anaesthesia on cognitive function after procedures other than cardiac surgery or neurosurgery in adult and in paediatric patients.

Early-Onset Scoliosis: A Review of History, Current Treatment, and Future Directions

Early-onset scoliosis (EOS) is defined as curvature of the spine in children >10° with onset before age 10 years. Young children with EOS are at risk for impaired pulmonary function because of the high risk of progressive spinal deformity and thoracic constraints during a critical time of lung development. The treatment of EOS is very challenging because the population is inhomogeneous, often medically complex, and often needs multiple surgeries. In the past, early spinal fusion was performed in children with severe progressive EOS, which corrected scoliosis but limited spine and thoracic growth and resulted in poor pulmonary outcomes. The current goal in treatment of EOS is to maximize growth of the spine and thorax by controlling the spinal deformity, with the aim of promoting normal lung development and pulmonary function. Bracing and casting may improve on the natural history of progression of spinal deformity and are often used to delay surgical intervention or in some cases obviate surgery. Recent advances in surgical implants and techniques have led to the development of growth-friendly implants, which have replaced early spine fusion as the surgical treatment of choice. Treatment with growth-friendly implants usually requires multiple surgeries and is associated with frequent complications. However, growth-friendly spine surgery has been shown to correct spinal deformity while allowing growth of the spine and subsequently lung growth.

Increased mitochondrial ATP production capacity in brain of healthy mice and a mouse model of isolated complex I deficiency after isoflurane anesthesia

We reported before that the minimal alveolar concentration (MAC) of isoflurane is decreased in complex I-deficient mice lacking the NDUFS4 subunit of the respiratory chain (RC) (1.55 and 0.81% at postnatal (PN) 22-25 days and 1.68 and 0.65% at PN 31-34 days for wildtype (WT) and CI-deficient KO, respectively). A more severe respiratory depression was caused by 1.0 MAC isoflurane in KO mice (respiratory rate values of 86 and 45 at PN 22-25 days and 69 and 29 at PN 31-34 days for anesthetized WT and KO, respectively). Here, we address the idea that isoflurane anesthesia causes a much larger decrease in brain mitochondrial ATP production in KO mice thus explaining their increased sensitivity to this anesthetic. Brains from WT and KO mice of the above study were removed immediately after MAC determination at PN 31-34 days and a mitochondria-enriched fraction was prepared. Aliquots were used for measurement of maximal ATP production in the presence of pyruvate, malate, ADP and creatine and, after freeze-thawing, the maximal activity of the individual RC complexes in the presence of complex-specific substrates. CI activity was dramatically decreased in KO, whereas ATP production was decreased by only 26% (p < 0.05). The activities of CII, CIII, and CIV were the same for WT and KO. Isoflurane anesthesia decreased the activity of CI by 30% (p < 0.001) in WT. In sharp contrast, it increased the activity of CII by 37% (p < 0.001) and 50% (p < 0.001) and that of CIII by 37% (p < 0.001) and 40% (p < 0.001) in WT and KO, respectively, whereas it tended to increase that of CIV in both WT and KO. Isoflurane anesthesia increased ATP production by 52 and 69% in WT (p < 0.05) and KO (p < 0.01), respectively. Together these findings indicate that isoflurane anesthesia interferes positively rather than negatively with the ability of CI-deficient mice brain mitochondria to convert their main substrate pyruvate into ATP.

Use of fentanyl and midazolam in mechanically ventilated children--Does the method of infusion matter?

BACKGROUND AND OBJECTIVE

Benzodiazepines and opioids are commonly used in pediatric intensive care unit. However, there is no previous study assessing the use of administering these drugs combined (single solution) or separately. We sought to evaluate the impact of these 2 different methods of providing sedation/analgesia in pediatric intensive care unit.

METHODS

One hundred twelve patients mechanically ventilated for more than 48 hours were randomized to receive a protocolized sedation regime comprising midazolam and fentanyl either separately (group 1, 57 patients) or combined as a single solution (group 2, 55 patients). Primary end point variable was the cumulated dose of midazolam and fentanyl.

RESULTS

The median cumulated doses of both fentanyl (0.19 vs 0.37 mg/kg, P < .05) and midazolam (28.8 vs 45.6 mg/kg, P < .05) required in group 2 were higher when compared with those of group 1. Moreover, group 2 patients had a significantly longer time of vasopressor drugs requirement and a higher number of patients developing tolerance.

CONCLUSION

Patients who received a single solution of midazolam and fentanyl had a higher cumulated dose of compared with those patients who did not. The potential risk for long-term neurologic effects on developing brains associated with this finding should be considered.

Learning, memory and synaptic plasticity in hippocampus in rats exposed to sevoflurane

PURPOSE

Developmental exposure to volatile anesthetics has been associated with cognitive deficits at adulthood. Rodent studies have revealed impairments in performance in learning tasks involving the hippocampus. However, how the duration of anesthesia exposure impact on hippocampal synaptic plasticity, learning, and memory is as yet not fully elucidated.

METHODS

On postnatal day 7(P7), rat pups were divided into 3 groups: control group (n=30), 3% sevoflurane treatment for 1h (Sev 1h group, n=30) and 3% sevoflurane treatment for 6h (Sev 6h group, n=28). Following anesthesia, synaptic vesicle-associated proteins and dendrite spine density and synapse ultrastructure were measured using western blotting, Golgi staining, and transmission electron microscopy (TEM) on P21. In addition, the effects of sevoflurane treatment on long-term potentiation (LTP) and long-term depression (LTD), two molecular correlates of memory, were studied in CA1 subfields of the hippocampus, using electrophysiological recordings of field potentials in hippocampal slices on P35-42. Rats' neurocognitive performance was assessed at 2 months of age, using the Morris water maze and novel-object recognition tasks.

RESULTS

Our results showed that neonatal exposure to 3% sevoflurane for 6h results in reduced spine density of apical dendrites along with elevated expression of synaptic vesicle-associated proteins (SNAP-25 and syntaxin), and synaptic ultrastructure damage in the hippocampus. The electrophysiological evidence indicated that hippocampal LTP, but not LTD, was inhibited and that learning and memory performance were impaired in two behavioral tasks in the Sev 6h group. In contrast, lesser structural and functional damage in the hippocampus was observed in the Sev 1h group.

CONCLUSION

Our data showed that 6-h exposure of the developing brain to 3% sevoflurane could result in synaptic plasticity impairment in the hippocampus and spatial and nonspatial hippocampal-dependent learning and memory deficits. In contrast, shorter-duration exposure (1h) results in less damage. These results provide further evidences that duration of anesthesia exposure could have differential effects on neuronal plasticity and neurocognitive performance.

Multicenter observational study comparing sedation/analgesia protocols for laser photocoagulation treatment of retinopathy of prematurity

OBJECTIVE

The aim of this study was to identify the best sedation/analgesia protocol for laser photocoagulation (PC) of retinopathy of prematurity (ROP).

STUDY DESIGN

This multicenter observational study included five hospitals, each using a specific sedation/analgesia protocol: local anesthesia with oxybuprocaine hydrochloride (Group L); intravenous pentazocine (Group P); intravenous fentanyl (Group F); air, oxygen and sevoflurane (AOS) inhalation (Group I). The groups were compared for pain responses, vital signs and adverse events.

RESULTS

Heart rates and systemic blood pressures were elevated by PC in Groups L and P and Groups L, P and F, respectively. Moreover, poor analgesic efficacy was recognized in Groups L, P and F. In contrast, Group I experienced hypothermia, enteral feeding intolerance and apnea more frequently.

CONCLUSION

From the viewpoint of sedation/pain relief, AOS anesthesia should be the best protocol. However, considering all the various factors together, the most reasonable one can be varied based on the patient's condition and hospital.

Pain Management in Neonatal Intensive Care: Evaluation of the Compliance With Guidelines

BACKGROUND

A pain management protocol was implemented in our neonatal intensive care unit in 2005, including individual pain assessments and pain treatment guidelines with a decision tree.

OBJECTIVES

To prospectively evaluate the degree of compliance of medical and nursing staff with the pain protocol.

METHODS

Prospectively recorded pain scores (COMFORTneo score) and all prescribed analgesics and sedatives for the calendar year 2011 were retrieved. The primary outcome was the degree of compliance to the protocol with respect to pain assessments and treatment; the secondary outcome consisted of reasons for noncompliance.

RESULTS

Of the 732 included patients, 660 (90%) received fewer than the stipulated 3 assessments per day. Eighty-six per cent of all assessments yielded a score between 9 and 14, suggesting a comfortable patient. In cases of high pain scores (≥14), reassessment within 60 minutes took place in 31% of cases and in 40% treatment was started or adjusted. In cases of low pain scores (≤8) during treatment, 13% of the 457 assessments were reassessed within 120 minutes and in 17% a dose reduction was performed.

CONCLUSIONS

Although the majority of pain assessments suggested comfortable patients, there is room for improvement with respect to reassessments after adjustment of analgesic/sedative treatment. Some protocol violations such as oversedation in palliative patients are acceptable but should be well documented.

Pediatric dental sedation: challenges and opportunities

High levels of dental caries, challenging child behavior, and parent expectations support a need for sedation in pediatric dentistry. This paper reviews modern developments in pediatric sedation with a focus on implementing techniques to enhance success and patient safety. In recent years, sedation for dental procedures has been implicated in a disproportionate number of cases that resulted in death or permanent neurologic damage. The youngest children and those with more complicated medical backgrounds appear to be at greatest risk. To reduce complications, practitioners and regulatory bodies have supported a renewed focus on health care quality and safety. Implementation of high fidelity simulation training and improvements in patient monitoring, including end-tidal carbon dioxide, are becoming recognized as a new standard for sedated patients in dental offices and health care facilities. Safe and appropriate case selection and appropriate dosing for overweight children is also paramount. Oral sedation has been the mainstay of pediatric dental sedation; however, today practitioners are administering modern drugs in new ways with high levels of success. Employing contemporary transmucosal administration devices increases patient acceptance and sedation predictability. While recently there have been many positive developments in sedation technology, it is now thought that medications used in sedation and anesthesia may have adverse effects on the developing brain. The evidence for this is not definitive, but we suggest that practitioners recognize this developing area and counsel patients accordingly. Finally, there is a clear trend of increased use of ambulatory anesthesia services for pediatric dentistry. Today, parents and practitioners have become accustomed to children receiving general anesthesia in the outpatient setting. As a result of these changes, it is possible that dental providers will abandon the practice of personally administering large amounts of sedation to patients, and focus instead on careful case selection for lighter in-office sedation techniques.

Toxic and protective effects of inhaled anaesthetics on the developing animal brain: systematic review and update of recent experimental work

BACKGROUND

Accumulating preclinical data indicate that neonatal exposure to general anaesthetics is detrimental to the central nervous system. Some studies, however, display potential protective effects of exactly the same anaesthetic agents on the immature brain. The effects of inhaled anaesthetics on the developing brain have received close attention from researchers, clinicians and the public in recent decades.

OBJECTIVES

To summarise the preclinical evidence reported in the last 5 years on both the deleterious effects and the neuroprotective potential in special indications, of inhaled anaesthetics on the developing brain.

DESIGN

A systematic review.

DATA SOURCES

PubMed search performed in June 2013.

ELIGIBILITY CRITERIA

Search terms included brain, development, inhaled anaesthetic, toxicity and protection within the scope of the last 5 years with animals. The reference lists of relevant articles and recent reviews were also hand-searched for additional studies. The type, dose and exposure duration of anaesthetics, species and age of animals, histopathologic indicators, outcomes and affected brain areas, neuro developmental test modules and outcomes, as well as other outcomes and comments were summarised.

RESULTS

Two hundred and nineteen relevant titles were initially revealed. In total, 81 articles were identified, with 68 articles assessing the detrimental effects induced by inhaled anaesthetics in the immature brain along with possible treatments. The remaining 13 articles focused on the protective profile of inhaled anaesthetics on perinatal hypoxic-ischaemic brain injury. Administration of inhaled anaesthetic agents to the immature brain was shown to be deleterious in several preclinical studies. In perinatal hypoxic-ischaemic brain injury models, pre- and postconditioning of inhalational anaesthetics exerted neuroprotective effects.

CONCLUSION

The majority of studies have linked inhaled anaesthetics to toxic effects in the neonatal brain of rodents, piglets and primates. Only a few studies, however, could demonstrate long-lasting cognitive impairment. The results of inhalational anaesthetic-induced neuroprotection in perinatal hypoxic-ischaemic brain injury are a promising basis for more research in this field. In general, prospective clinical trials are needed to further differentiate the effects of inhaled anaesthetics on the immature brain.

Propofol: a review of its role in pediatric anesthesia and sedation

Propofol is an intravenous agent used commonly for the induction and maintenance of anesthesia, procedural, and critical care sedation in children. The mechanisms of action on the central nervous system involve interactions at various neurotransmitter receptors, especially the gamma-aminobutyric acid A receptor. Approved for use in the USA by the Food and Drug Administration in 1989, its use for induction of anesthesia in children less than 3 years of age still remains off-label. Despite its wide use in pediatric anesthesia, there is conflicting literature about its safety and serious adverse effects in particular subsets of children. Particularly as children are not "little adults", in this review, we emphasize the maturational aspects of propofol pharmacokinetics. Despite the myriad of propofol pharmacokinetic-pharmacodynamic studies and the ability to use allometrical scaling to smooth out differences due to size and age, there is no optimal model that can be used in target controlled infusion pumps for providing closed loop total intravenous anesthesia in children. As the commercial formulation of propofol is a nutrient-rich emulsion, the risk for bacterial contamination exists despite the Food and Drug Administration mandating addition of antimicrobial preservative, calling for manufacturers' directions to discard open vials after 6 h. While propofol has advantages over inhalation anesthesia such as less postoperative nausea and emergence delirium in children, pain on injection remains a problem even with newer formulations. Propofol is known to depress mitochondrial function by its action as an uncoupling agent in oxidative phosphorylation. This has implications for children with mitochondrial diseases and the occurrence of propofol-related infusion syndrome, a rare but seriously life-threatening complication of propofol. At the time of this review, there is no direct evidence in humans for propofol-induced neurotoxicity to the infant brain; however, current concerns of neuroapoptosis in developing brains induced by propofol persist and continue to be a focus of research.

CT angiography-guided single-stage release of adjacent webspaces in non-Apert syndactyly

We describe the CT angiography protocol and surgical technique utilized at our institution for single-stage release of adjacent web-spaces in non-Apert syndactyly. In a series of seven consecutive hands we analyse syndactyly anatomy, CT angiographic findings, operative details, and complications. Outcomes were assessed with a functional activity evaluation, range of motion, and a parental visual analogue scale. Seven affected hands in four patients underwent single-stage release of adjacent webspaces. In all cases, the CT angiogram correctly predicted the presence of at least one artery supplying each digit. There were no cases of digital ischemia or loss. Angiographically guided, single-stage release of adjacent webspaces is technically feasible and benefits patients by reducing the number of surgical stages and allowing complete release to be achieved at an earlier age compared with the standard multi-stage approach.

LEVEL OF EVIDENCE

IV.

Nonanesthesia magnetic resonance enterography in young children: feasibility, technique, and performance

OBJECTIVES

The aim of the present study was to demonstrate the effectiveness and cost savings of a nonanesthesia approach to magnetic resonance enterography (MRE) in 14 young pediatric patients (age 4-7 years) with clinically suspected early-onset inflammatory bowel disease using an MRE protocol.

METHODS

MRE was performed using a combination of an abbreviated imaging protocol, magnetic resonance imaging video goggles, and Child Life Services support. MRE results were correlated with both colonoscopy and pathology results using Pearson correlation coefficient. Sensitivity, specificity, and positive and negative predictive values were calculated.

RESULTS

MRE was performed successfully in 13 of 14 patients (age range 4 years 0 months to 7 years 6 months). MRE findings matched with results in 12 of 13 patients in whom colonoscopy was successfully performed. Both MRE and colonoscopy demonstrated a high specificity (100%) and a positive predictive value (100%), but a low sensitivity (43%) and a negative predictive value (50%).

CONCLUSIONS

MRE can be successfully performed in children ages 4 to 7 years using this approach. In addition to decreased risks to the child, the lack of anesthesia also offers a potential overall cost reduction.

The effects of anaesthetics on postoperative physiological reactions: a meta-analysis

This study aimed to systematically investigate the effects of different anaesthetics on postoperative physiological reactions compared with placebo. The literature search was conducted using three databases: PubMed, EMBASE, and the Cochrane Library. Studies published from January 1990 to January 2015 were screened. The language was restricted to English. Heterogeneity was analyzed by the Q test and I(2) statistic. A fixed-effect model was used for homogenous data and a random-effects model for heterogeneous data. The odds ratio (OR) and 95% confidence interval (CI) were calculated to monitor the incidences of overall adverse events, arterial blood pressure, and cardiac abnormalities. Sensitivity analysis was performed to estimate the strength of the meta-analysis, and publication bias was analyzed using Egger's test. A total of 24 articles were included in this meta-analysis. There were 1,810 and 1,806 cases in the anaesthetic group and the placebo group, respectively. The incidence of overall adverse events was significantly lower in the anaesthetic group compared with the placebo group (OR = 0.57; 95% CI, 0.38-0.84). No publication bias was observed, and no inverse estimates were calculated using sensitivity analysis. There was no significant difference for the incidence of arterial blood pressure (OR = 4.62; 95% CI, 0.90-23.70) and cardiac abnormalities (OR = 1.18; 95% CI, 0.53-2.63) between the two groups. Although the incidence of overall adverse events was decreased in the anaesthetic group, it is impossible to determine whether the use of anaesthetics during surgical operation has a protective effect on postoperative physiological reactions.

Neurodevelopmental outcomes after initial childhood anesthetic exposure between ages 3 and 10 years

INTRODUCTION

Epidemiologic studies examining the association between anesthetic exposure and neurodevelopmental outcomes have primarily focused on exposures occurring under 3 years of age. In this study, we assess outcomes associated with initial anesthetic exposure occurring between 3 and 10 years of age.

METHODS

We used data from the Western Australian Pregnancy Cohort (Raine) Study to examine the risk of cognitive deficit at age 10 in children with initial anesthetic exposure between 3 and 5 years and between 5 and 10 years of age compared with children unexposed at those ages. The cohort included 2868 children born from 1989 to 1992 evaluated using a range of neuropsychological tests. A modified multivariable Poisson regression model was used to determine the adjusted association of initial anesthetic exposure in each age group with outcomes.

RESULTS

Exposed and unexposed children were found to have similar neuropsychological test results except for the McCarron Assessment of Neuromuscular Development (MAND) motor function scores. Even after adjusting for demographic and comorbidity differences, children exposed to anesthesia had a higher risk of motor deficit after initial exposure between ages 3 and 5 years (adjusted risk ratio, 2.32; 95% confidence interval, 1.42-3.79) and between 5 and 10 years (adjusted risk ratio, 2.33; 95% confidence interval, 1.21-4.48) compared with unexposed children.

CONCLUSIONS

Initial exposure to anesthesia after age 3 had no measurable effects on language or cognitive function. Decreased motor function was found in children initially exposed after age 3 even after accounting for comorbid illness and injury history. These results suggest that there may be distinct windows of vulnerability for different neurodevelopmental domains in children.

Induction of TNF-α signaling cascade in neonatal rat brain during propofol anesthesia

Propofol anesthesia can trigger pro- and anti-apoptotic signaling pathways in the rat brain. In our previous work, we demonstrated that propofol causes widespread apoptotic neurodegeneration in 7-postnatal-day-old (PND7) but not in PND14 rat neurons. The mechanism responsible for these opposing outcomes is unknown, apparently linked to the specific stage of brain development. The present study aims to elucidate the anti-apoptotic process that is activated in the cortex and thalamus of PND14 Wistar rats during the first 48 h after the onset of propofol anesthesia. We showed that the expression of tumor necrosis factor-α (TNF-α) and several components of its pathway, TNFR1 and caspase-8, was significantly increased in the cortex and thalamus. Nuclear factor kappa B (NF-κB) p65 was downregulated in the cortex and upregulated in the thalamus. The expression of c-Fos was upregulated only in the cortex, showing opposed profile compared to NF-κB p65. Double immunofluorescence staining revealed the colocalization of NF-κB p65 with neuronal marker (NeuN), but with predominantly cytoplasmic localization. Finally, X-linked inhibitor of apoptosis protein (XIAP) was upregulated in both examined structures. Immunohistochemical staining with Iba-1 revealed that the treatment did not induce changes in microglial morphology. Our results (i) reveal that the simultaneous activation of pro- and anti-apoptotic signaling occurs after propofol anesthesia, and (ii) pinpoint the potential neuroprotective role of XIAP in anesthesia-induced neurotoxicity.

Growing Rods Versus Shilla Growth Guidance: Better Cobb Angle Correction and T1-S1 Length Increase But More Surgeries

STUDY DESIGN

Retrospective comparison.

OBJECTIVES

To compare treatment of early-onset scoliosis (EOS) with Shilla growth guidance versus distraction-based dual growing rods (GR).

SUMMARY OF BACKGROUND DATA

We are not aware of any prior studies comparing the Shilla procedure with other surgical procedures in the treatment of EOS.

METHODS

The authors performed a multicenter case-matched comparison of patients with EOS treated with Shilla versus dual spine-spine GR from 1995 to 2009. A total of 36 Shilla patients from 3 centers were matched with 36 GR patients from the database by age at index surgery (±1 year), preoperative Cobb angle (±15°), and diagnosis (neuromuscular, congenital, idiopathic, or syndromic). Average follow-up was similar between groups (GR, 4.3 years; Shilla, 4.6 years; p = .353).

RESULTS

Average Cobb angle improvement preoperatively to latest follow-up was 36° (range, 72° to 36°) in the GR group versus 23° (range, 69° to 45°) in the Shilla group (p = .0124). T1-S1 length increased 8.8 cm in patients treated with GR, compared with 6.4 cm in Shilla patients (p = .0170). Shilla patients had fewer surgeries (2.8) than patients in the GR group (7.4) (p < .001) but had a higher rate of unplanned surgeries for implant complications (Shilla, 1.3; GR, 0.5; p = .0151). When revisions for implant complications done at the time of scheduled lengthenings and revisions for construct maintenance were included, the groups did not differ significantly in the number of procedures for implant complications (Shilla, 1.4; GR, 1.5; p = .9451). The overall complication rate did not differ significantly between groups (Shilla, 1.9 [range, 0-7]; GR, 1.3 [range, 0-9]; p = .2085).

CONCLUSIONS

The GR group had a greater improvement in Cobb angle and a greater increase in T1-S1 length than Shilla. The GR patients had more surgeries but Shilla patients had more unplanned procedures. The rate of complications overall did not differ significantly between groups.

Systemic physiology and neuroapoptotic profiles in young and adult rats exposed to surgery: A randomized controlled study comprising four different anaesthetic techniques

BACKGROUND

Experimental evidence indicates that general anaesthetics can induce apoptotic neurodegeneration in the developing brain. The majority of these studies have been performed in the absence of surgery and it currently remains unclear how the presence of surgical stimuli would influence neuroapoptosis as well as systemic homeostasis. Here we explored this possibility by performing dorsal skin flap surgery in young and adult rats under four distinct currently used anaesthesia regimens.

METHODS

Young (21-days) and adult (2 months) male Sprague-Dawley rats were randomized to 150 min exposure to one of four anaesthetics regimens: (i) sevoflurane/dexmedetomidine, (ii) sevoflurane/fentanyl; (iii) propofol/dexmedetomidine, and (iv) propofol/fentanyl. Animals underwent a dorsal skin flap procedure while physiologic, metabolic and biochemical parameters were closely monitored. Neuroapoptotic profiles were evaluated in the cortex, thalamus and hippocampus (CA1 and CA3) at the end of the procedure in each experimental group.

RESULTS

Significant perturbations of systemic homeostasis were found under all anaesthetic regimens. Hyperglycemia and decreased heart rate were particularly relevant in experimental groups receiving dexmedetomidine, while propofol administration was associated with increased systemic lactate levels and metabolic acidosis. A substantial difference in anaesthesia/surgery-induced neuroapoptosis was found between young and adult rats in several brain regions. Combination of sevoflurane and dexmedetomidine resulted in the highest number of caspase-3 positive cells, although the extent of cell death remained relatively low in all experimental groups.

CONCLUSION

Combination of anaesthesia and surgery induces significant perturbations of physiological parameters in both young and adult spontaneously breathing rats undergoing surgery. These observations further enlighten the need for detailed physiological monitoring under these experimental conditions. Although some statistically significant differences in activated caspase-3 profiles were detected between experimental groups, the overall extent of neuronal cell death remained very low under all conditions questioning, thereby, the physiological significance of apoptotic neurodegeneration in the context of anaesthesia and surgery.