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Journal ArticleDOI

Near-infrared spectroscopy: exposing the dark (venous) side of the circulation.

01 Jan 2014-Pediatric Anesthesia (Paediatr Anaesth)-Vol. 24, Iss: 1, pp 74-88
TL;DR: Near‐infrared spectroscopy provides noninvasive continuous access to the venous side of regional circulations that can approximate organ‐specific and global measures to facilitate the detection of circulatory abnormalities and drive goal‐directed interventions to reduce end‐organ ischemic injury.
Abstract: The safety of anesthesia has improved greatly in the past three decades. Standard perioperative monitoring, including pulse oximetry, has practically eliminated unrecognized arterial hypoxia as a cause for perioperative injury. However, most anesthesia-related cardiac arrests in children are now cardiovascular in origin, and standard monitoring is unable to detect many circulatory abnormalities. Near-infrared spectroscopy provides noninvasive continuous access to the venous side of regional circulations that can approximate organ-specific and global measures to facilitate the detection of circulatory abnormalities and drive goal-directed interventions to reduce end-organ ischemic injury.
Citations
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Journal ArticleDOI
TL;DR: Test the hypothesis that near-infrared spectroscopy (NIRS)-derived cerebral and somatic/renal regional saturations can predict survival by analyzing relationships between standard hemodynamic measures, direct and NIRS measures of saturation, and outcome.

83 citations


Cites background from "Near-infrared spectroscopy: exposin..."

  • ...A linear combination of cerebral and somatic NIRS saturations can predict both SvO2 [14] and lactate [9, 10]....

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  • ...Somatic/renal blood flow is highly influenced by changes in SVR that can be detected by NIRS [10, 35]....

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  • ...Attention to this concept is important to clinical interpretation of NIRS-estimated or directly measured venous saturations [10, 31]....

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Journal ArticleDOI
TL;DR: Brain oxygenation changed at distinct points during surgery in all ages, reflecting fundamental cerebral responses to hypothermic CPB, ischemia, and reperfusion, consistent with experimental work in animals.
Abstract: Background Deep hypothermic circulatory arrest is a widely used technique in pediatric cardiac surgery that carries a risk of neurologic injury. Previous work in neonates identified distinct changes in cerebral oxygenation during surgery. This study sought to determine whether the intraoperative changes in cerebral oxygenation vary between neonates, infants, and children and whether the oxygenation changes are associated with postoperative cerebral dysfunction. Methods The study included eight neonates, ten infants, and eight children without preexisting neurologic disease. Cerebrovascular hemoglobin oxygen saturation (ScO2), an index of brain oxygenation, was monitored intraoperatively by near‐infrared spectroscopy. Body temperature was reduced to 15 degrees Celsius during cardiopulmonary bypass (CPB) before commencing circulatory arrest. Postoperative neurologic status was judged as normal or abnormal (seizures, stroke, coma). Results Relative to preoperative levels, the age groups experienced similar changes in ScO2 during surgery: Sco sub 2 increased 30 plus/minus 4% during deep hypothermic CPB, it decreased 62 plus/minus 5% by the end of arrest, and it increased 20 plus/minus 5% during CPB recirculation (all P < 0.001); after rewarming and removal of CPB, ScO2 returned to preoperative levels. During arrest, the half‐life of ScO2 was 9 plus/minus 1 min in neonates, 6 plus/minus 1 min in infants, and 4 plus/minus 1 min in children (P < 0.001). Postoperative neurologic status was abnormal in three (12%) patients. The ScO2 increase during deep hypothermic CPB was less in these patients than in the remaining study population (3 plus/minus 2% versus 33 plus/minus 4%, P < 0.00l). There were no other significant ScO2 differences between outcome groups. Conclusions Brain oxygenation changed at distinct points during surgery in all ages, reflecting fundamental cerebral responses to hypothermic CPB, ischemia, and reperfusion. However, the changes in Sc sub O2 half‐life with age reflect developmental differences in the rate of cerebral oxygen utilization during arrest, consistent with experimental work in animals. Certain intraoperative cerebral oxygenation patterns may be associated with postoperative cerebral dysfunction and require further study.

69 citations

Journal ArticleDOI
TL;DR: To assess the impact of sevoflurane and anesthesia‐induced hypotension on brain perfusion in children younger than 6 months, a large number of patients were referred to the neonatal intensive care unit.
Abstract: SummaryObjective/Aim To assess the impact of sevoflurane and anesthesia-induced hypotension on brain perfusion in children younger than 6 months. Background Safe lower limit of blood pressure during anesthesia in infant is unclear, and inadequate anesthesia can lead to hypotension, hypocapnia, and low cerebral perfusion. Insufficient cerebral perfusion in infant during anesthesia is an important factor of neurological morbidity. In two previous studies, we assessed the impact of sevoflurane anesthesia on cerebral blood flow (CBF) by transcranial Doppler (TCD) and on brain oxygenation by NIRS, in children ≤2 years. As knowledge about consequences of anesthesia-induced hypotension on cerebral perfusion in children ≤6 months is scarce, we conducted a retrospective analysis to compare the data of CBF and brain oxygenation, in this specific population. Methods We performed a retrospective analysis of data collected from our two previous studies. Baseline values of TCD or NIRS were recorded and then during sevoflurane anesthesia. From a database of 338 patients, we excluded all patients older than 6 months. Then, we compared physiological variables of TCD and NIRS population to ensure that the two groups were comparable. We compared rSO2c and TCD measurements variation according to MAP value during sevoflurane anesthesia, using anova and Student–Newman–Keuls for posthoc analysis. Results One hundred and eighty patients were included in the analysis. TCD and NIRS groups were comparable. CBF velocities (CBFV) or rSO2c reflects a good cerebral perfusion when MAP is above 45 mmHg. When MAP is between 35 and 45 mmHg, CBFV variation reflects a reduction of CBF, but rSO2c increase is the consequence of a still positive balance between CMRO2 and O2 supply. Below 35 mmHg of MAP during anesthesia, CBFV decrease and rSO2c variation from baseline is low. For each category of MAP and for the two groups, etCo2 and expired fraction of sevoflurane (FeSevo) were comparable (anova P > 0.05). Conclusion In a healthy infant without dehydration, with normal PaCO2 and hemoglobin value, scheduled for short procedures, MAP is a good proxy of cerebral perfusion as we found that CBF assessed by CBFV and rSO2c decreased proportionally with cerebral perfusion pressure. During 1 MAC sevoflurane anesthesia, maintaining MAP beyond 35 mmHg during anesthesia is probably safe and sufficient. But when MAP decreases below 35 mmHg, CBF decreases and rSO2c variation from baseline is low despite CMRO2 reduction. In this situation, cerebral metabolic reserve is low and further changes of systemic conditions may be poorly tolerated by the brain.

55 citations

Journal ArticleDOI
TL;DR: Mild and moderate low cerebral oxygenation occurred frequently, whereas severe low cerebral saturation was uncommon, and low mean arterial pressure was common and not well associated withLow cerebral saturation.
Abstract: Background:General anesthesia during infancy is associated with neurocognitive abnormalities. Potential mechanisms include anesthetic neurotoxicity, surgical disease, and cerebral hypoxia–ischemia. This study aimed to determine the incidence of low cerebral oxygenation and associated factors during

54 citations


Additional excerpts

  • ...Laparoscopic technique, n (%) 26 (33) 36 (47) 4 (8) 2 (33) 14 (20) 5 (9) 9 (11) 1 (3) 97 (21)...

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Journal ArticleDOI
TL;DR: To assess the impact of sevoflurane and anesthesia‐induced hypotension on brain oxygenation in children younger than 2 years, a large number of patients were referred to the neonatal intensive care unit.
Abstract: SummaryObjective/Aim To assess the impact of sevoflurane and anesthesia-induced hypotension on brain oxygenation in children younger than 2 years. Background Inhalational induction with sevoflurane is the most commonly used technique in young children. However, the effect of sevoflurane on cerebral perfusion has been only studied in adults and children older than 1 year. The purpose of this study was to assess the impact of sevoflurane anesthesia on brain oxygenation in neonates and infants, using near-infrared spectroscopy. Methods Children younger than 2 years, ASA I or II, scheduled for abdominal or orthopedic surgery were included. Induction of anesthesia was started by sevoflurane 6% and maintained with an expired fraction of sevoflurane 3%. Mechanical ventilation was adjusted to maintain an endtidal CO2 around 39 mmHg. Brain oxygenation was assessed measuring regional cerebral saturation of oxygen (rSO2c), measured by NIRS while awake and 15 min after induction, under anesthesia. Mean arterial pressure (MAP) variation was recorded. Results Hundred and ninety-five children were included. Anesthesia induced a significant decrease in MAP (−27%). rSO2c increased significantly after induction (+18%). Using children age for subgroup analysis, we found that despite MAP reduction, rSO2c increase was significant but smaller in children ≤6 months than in children >6 months (≤6 months: rSO2c = +13%, >6 months: rSO2c = +22%; P < 0.0001). Interindividual comparison showed that, during anesthesia at steady-state with comparable CMRO2, rSO2c values were significantly higher when MAP was above 36 mmHg. And the higher the absolute MAP value during anesthesia was, the higher the rSO2c was. We observed a rSO2c variation ≤0 in 21 patients among the 195 studied, and the majority of these patients were younger than 6 months (n = 19). No increase or decrease of rSO2c during anesthesia despite reduction of CMRO2 can be explained by a reduction of oxygen supply. Using the ROC curves, we determined that the threshold value of MAP under anesthesia, associated with rSO2c variation ≤0%, was 39 mmHg in all the studied population (AUC: 0.90 ± 0.02; P < 0.001). In children younger than 6 months, this value of MAP was 33 mmHg, and 43 mmHg in children older than 6 months. Conclusion Despite a significant decrease of MAP, 1 MAC of sevoflurane induced a significant increase in regional brain oxygenation. But subgroup analysis showed that MAP decrease had a greater impact on brain oxygenation, in children younger than 6 months. According to our results, MAP value during anesthesia should not go under 33 mmHg in children ≤6 months and 43 mmHg in children >6 months, as further changes in MAP, PaCO2 or hemoglobin during anesthesia may be poorly tolerated by the brain.

48 citations

References
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Journal ArticleDOI
TL;DR: This study randomly assigned patients who arrived at an urban emergency department with severe sepsis or septic shock to receive either six hours of early goal-directed therapy or standard therapy (as a control) before admission to the intensive care unit.
Abstract: Background Goal-directed therapy has been used for severe sepsis and septic shock in the intensive care unit. This approach involves adjustments of cardiac preload, afterload, and contractility to balance oxygen delivery with oxygen demand. The purpose of this study was to evaluate the efficacy of early goal-directed therapy before admission to the intensive care unit. Methods We randomly assigned patients who arrived at an urban emergency department with severe sepsis or septic shock to receive either six hours of early goal-directed therapy or standard therapy (as a control) before admission to the intensive care unit. Clinicians who subsequently assumed the care of the patients were blinded to the treatment assignment. In-hospital mortality (the primary efficacy outcome), end points with respect to resuscitation, and Acute Physiology and Chronic Health Evaluation (APACHE II) scores were obtained serially for 72 hours and compared between the study groups. Results Of the 263 enrolled patients, 130 were ...

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Journal ArticleDOI
Frans F. Jöbsis1
23 Dec 1977-Science
TL;DR: Observations by infrared transillumination in the exposed heart and in the brain in cephalo without surgical intervention show that oxygen sufficiency for cytochrome a,a3, function, changes in tissue blood volume, and the average hemoglobin-oxyhemoglobin equilibrium can be recorded effectively and in continuous fashion for research and clinical purposes.
Abstract: The relatively good transparency of biological materials in the near infrared region of the spectrum permits sufficient photon transmission through organs in situ for the monitoring of cellular events. Observations by infrared transillumination in the exposed heart and in the brain in cephalo without surgical intervention show that oxygen sufficiency for cytochrome a,a3, function, changes in tissue blood volume, and the average hemoglobin-oxyhemoglobin equilibrium can be recorded effectively and in continuous fashion for research and clinical purposes. The copper atom associated with heme a3 did not respond to anoxia and may be reduced under normoxic conditions, whereas the heme-a copper was at least partially reducible.

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TL;DR: The goal of therapy for bradycardia or tachycardia is to rapidly identify and treat patients who are hemodynamically unstable or symptomatic due to the arrhythmia.
Abstract: The goal of therapy for bradycardia or tachycardia is to rapidly identify and treat patients who are hemodynamically unstable or symptomatic due to the arrhythmia. Drugs or, when appropriate, pacing may be used to control unstable or symptomatic bradycardia. Cardioversion or drugs or both may be used to control unstable or symptomatic tachycardia. ACLS providers should closely monitor stable patients pending expert consultation and should be prepared to aggressively treat those with evidence of decompensation.

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18 Mar 2000-BMJ
TL;DR: Focusing on data for near misses may add noticeably more value to quality improvement than a sole focus on adverse events, and an environment fostering a rich reporting culture must be created to capture accurate and detailed data about nuances of care.
Abstract: Reducing mishaps from medical management is central to efforts to improve quality and lower costs in health care. Nearly 100 000 patients are estimated to die preventable deaths annually in hospitals in the United States, with many more incurring injuries at an annual cost of $9 billion. Underreporting of adverse events is estimated to range from 50%-96% annually.1–3 This annual toll exceeds the combined number of deaths and injuries from motor and air crashes, suicides, falls, poisonings, and drownings.4 Many stakeholders in health care have begun to work together to resolve the moral, scientific, legal, and practical dilemmas of medical mishaps. To achieve this goal, an environment fostering a rich reporting culture must be created to capture accurate and detailed data about nuances of care. Outcomes in complex work depend on the integration of individual, team, technical, and organisational factors. 5 6 A continuum of cascade effects exists from apparently trivial incidents to near misses and full blown adverse events. 7 8 Consequently, the same patterns of causes of failure and their relations precede both adverse events and near misses. Only the presence or absence of recovery mechanisms determines the actual outcome.9 The National Research Council defines a safety “incident” as an event that, under slightly different circumstances, could have been an accident.10 Focusing on data for near misses may add noticeably more value to quality improvement than a sole focus on adverse events. Schemes for reporting near misses, “close calls,” or sentinel (“warning”) events have been institutionalised in aviation,w1 w2 nuclear power technology,w3 w4 petrochemical processing, steelw5 production,w6 military operations, and air transportation.w7-w11 In health care, efforts are now being made to create incident reporting systems for medical near misses 8 11–15 to supplement the limited …

1,083 citations

Journal ArticleDOI
TL;DR: Microcirculatory alterations improve rapidly in septic shock survivors but not in patients dying with multiple organ failure, regardless of whether shock has resolved.
Abstract: Objective:To characterize the time course of microcirculatory alterations and their relation to outcome in patients with septic shock.Design:Prospective, observational study.Setting:Thirty-one-bed, medico-surgical intensive care unit in a university hospital.Patients:Forty-nine patients with septic

1,076 citations