Age-Stratified Propofol Dosage for Pediatric Procedural Sedation and Analgesia.

BACKGROUND: Procedural sedation and analgesia (PSA) for diagnostic and minimally invasive therapeutic procedures has become common practice in children of all ages. Based on our clinical experience, we suspected an inverse relation between age and dosage. However, a schedule for age-stratified propofol induction and maintenance dosage for PSA was not available and could be helpful to many anesthesiologists as a reference. METHODS: We performed a retrospective cohort study of children who received procedural sedation at the Wilhelmina Children's Hospital (WKZ), a tertiary pediatric hospital part of the University Medical Center Utrecht (UMCU), between June 2007 and December 2020. We studied whether the induction (mg·kg -1 ) and maintenance (mg·kg -1 ·h -1 ) dosage is age-dependent using linear regression models. RESULTS: A total of 6438 pediatric procedures were retrieved from Anesthesia Information Management Systems (AIMS). A total of 5567 records were available for induction dose analysis and 5420 records for analysis of the maintenance dose. After adjustment for sex, American Society of Anesthesiologists (ASA) physical status classification, opioid administration, and diagnostic or interventional, we obtained a coefficient of -0.11 (95% confidence interval [CI], -0.12 to -0.11) for age (years) from a multivariable linear regression model for propofol induction dosage (mg·kg -1 ) and a coefficient of -0.36 (95% CI, -0.39 to -0.34) for age (years) for propofol maintenance dosage. CONCLUSIONS: We found a noteworthy inverse age-effect on propofol dosage for both induction and maintenance of pediatric procedural sedation. Furthermore, our study revealed that remarkably higher propofol sedation doses were needed for infants and toddlers than previously expected and reported.

Definitions of low cardiac output syndrome after cardiac surgery and their effect on the incidence of intraoperative LCOS: A literature review and cohort study.

Objectives: Low cardiac output syndrome (LCOS) is a serious complication after cardiac surgery. Despite scientific interest in LCOS, there is no uniform definition used in current research and clinicians cannot properly compare different study findings. We aimed to collect the LCOS definitions used in literature and subsequently applied the definitions obtained to existing data to estimate their effect on the intraoperative LCOS incidences in adults, children and infants. Design: This is a literature review, followed by a retrospective cohort study. Setting: This is a single-institutional study from a university hospital in the Netherlands. Participants: Patients from all ages undergoing cardiac surgery with cardiopulmonary bypass between June 2011 and August 2018. Interventions: We obtained different definitions of LCOS used in the literature and applied these to data obtained from an anesthesia information management system to estimate intraoperative incidences of LCOS. We compared intraoperative incidences of LCOS in different populations based on age (infants, children and adults). Measurements and main results: The literature search identified 262 LCOS definitions, that were applied to intraoperative data from 7,366 patients. Using the 10 most frequently published LCOS definitions, the obtained incidence estimates ranged from 0.4 to 82% in infants, from 0.6 to 56% in children and from 1.5 to 91% in adults. Conclusion: There is an important variety in definitions used to describe LCOS. When applied to data obtained from clinical care, these different definitions resulted in large distribution of intraoperative LCOS incidence rates. We therefore advocate for standardization of the LCOS definition to improve clinical understanding and enable adequate comparison of outcomes and treatment effects both in daily care and in research.

Defining the awake baseline blood pressure in patients undergoing carotid endarterectomy.

BACKGROUND: To minimize the incidence of intraoperative stroke following carotid endarterectomy (CEA) under general anesthesia, blood pressure (BP) is suggested to be maintained between "awake baseline" BP and 20% above. However, there is neither a widely accepted protocol nor a definition to determine this awake BP. In this study, we analyzed the BP during hospital admission in the days before CEA and propose a definition of how to determine awake BP. METHODS: In our cohort of 1180 CEA-patients, all noninvasive BP measurements were retrospectively analyzed. BP was measured during preoperative outpatient screening (POS), the last three days before surgery at the ward and in the operating room (OR) directly before anesthesia. Primary outcome was the comparability of all these preoperative BP measurements. Secondary outcome was the comparability of preoperative BP measurements stratified for postoperative stroke within 30 days. RESULTS: POS BP (148±22/80±12 mmHg [mean arterial pressure, MAP: 103±14 mmHg]) and the BP measured on the ward 3, 2, 1 days before surgery and on the day of surgery (146±25/77±13 [MAP: 100±15]), (142±23/76±13 [MAP: 98±15]), (145±23/76±12 [MAP: 99±14]) and (144±22/75±12 mmHg [MAP: 98±14]) were comparable (all P=NS). However, BP in the OR directly before anesthesia was higher, (163±27/88±15 mmHg [MAP: 117±18mmHg]) (P<0.01 vs. all other preoperative moments). A significant higher preinduction systolic BP and MAP was observed in patients suffering a stroke within 30 days compared to patients without (P=0.03 and 0.04 respectively). CONCLUSIONS: Awake BP should be determined by averaging available BP values collected preoperatively on the ward and POS. BP measured in the OR directly before induction of anesthesia overestimates "awake" BP; and therefore, it should not be used.

Hypoxemia during procedural sedation in adult patients: a retrospective observational study.

PURPOSE: Since 2010, new guidelines for procedural sedation and the Helsinki Declaration on Patient Safety have increased patient safety, comfort, and acceptance considerably. Nevertheless, the administration of sedatives and opioids during sedation procedures may put the patient at risk of hypoxemia. However, data on hypoxemia during procedural sedation are scarce. Here, we studied the incidence and severity of hypoxemia during procedural sedations in our hospital. METHODS: A historical, single-centre cohort study was performed at the University Medical Centre Utrecht (UMCU), a tertiary centre in the Netherlands. Data from procedural sedation in our hospital between 1 January 2011 and 31 December 2018 (3,459 males and 2,534 females; total, 5,993) were extracted from our Anesthesia Information Management System. Hypoxemia was defined as peripheral oxygen saturation < 90% lasting at least two consecutive minutes. The severity of hypoxemia was calculated as area under the curve. The relationship between the severity of hypoxemia and body mass index (BMI), American Society of Anesthesiologists (ASA) Physical Status classification, and duration of the procedure was investigated. The primary outcome was the incidence of hypoxemia. RESULTS: Twenty-nine percent of moderately to deeply sedated patients developed hypoxemia. A high incidence of hypoxemia was found in patients undergoing procedures in the heart catheterization room (54%) and in patients undergoing bronchoscopy procedures (56%). Hypoxemia primarily occurred in longer lasting procedures (> 120 min) and especially in the latter phases of the procedures. There was no relationship between severity of hypoxemia and BMI or ASA Physical Status. CONCLUSIONS: This study showed that a considerable number of patients are at risk of hypoxemia during procedural sedation with a positive correlation shown with increasing duration of medical procedures. Additional prospective research is needed to investigate the clinical consequences of this cumulative hypoxemia.

RéSUMé: OBJECTIF: Depuis 2010, les nouvelles lignes directrices pour la sédation procédurale et la Déclaration d'Helsinki concernant la sécurité des patients ont considérablement augmenté la sécurité, le confort et l'acceptation des patients. L'administration de sédatifs et d'opioïdes pendant les interventions sous sédation peut toutefois mettre le patient à risque d'hypoxémie. Cependant, les données concernant l'hypoxémie pendant une sédation procédurale sont rares. Ici, nous avons étudié l'incidence et la sévérité de l'hypoxémie pendant la sédation procédurale dans notre hôpital. MéTHODE: Une étude de cohorte historique monocentrique a été réalisée au Centre médical universitaire d'Utrecht (UMCU), un centre tertiaire aux Pays-Bas. Les données des sédations procédurales réalisées dans notre hôpital entre le 1er janvier 2011 et le 31 décembre 2018 (3459 hommes et 2534 femmes; au total, 5993 patients) ont été extraites de notre système de gestion de l'information en anesthésie. L'hypoxémie a été définie comme une saturation périphérique en oxygène < 90 % durant au moins deux minutes consécutives. La sévérité de l'hypoxémie a été calculée en tant que surface sous la courbe. Les relations entre la sévérité de l'hypoxémie et l'indice de masse corporelle (IMC), la classification du statut physique selon l'American Society of Anesthesiologists (ASA) et la durée de l'intervention ont été étudiées. Le critère d'évaluation principal était l'incidence d'hypoxémie. RéSULTATS: Vingt-neuf pour cent des patients sous sédation modérée à profonde ont développé une hypoxémie. Une incidence élevée d'hypoxémie a été observée chez les patients subissant des interventions en salle d'hémodynamie (54 %) et chez les patients subissant des bronchoscopies (56 %). L'hypoxémie est principalement survenue lors d'interventions plus longues (> 120 min) et particulièrement dans les phases plus tardives des interventions. Aucune relation n'a été observée entre la sévérité de l'hypoxémie et l'IMC ou le statut physique ASA. CONCLUSION: Cette étude a démontré qu'un nombre considérable de patients sont à risque d'hypoxémie pendant la sédation procédurale, une corrélation positive ayant été démontrée avec une durée prolongée des interventions médicales. D'autres recherches prospectives sont nécessaires pour étudier les conséquences cliniques de cette hypoxémie cumulée.

Accuracy of remote continuous respiratory rate monitoring technologies intended for low care clinical settings: a prospective observational study.

PURPOSE: Altered respiratory rate (RR) has been identified as an important predictor of serious adverse events during hospitalization. Introduction of a well-tolerated continuous RR monitor could potentially reduce serious adverse events such as opioid-induced respiratory depression. The purpose of this study was to investigate the ability of different monitor devices to detect RR in low care clinical settings. METHODS: This was a prospective method-comparison study with a cross-sectional design. Thoracic impedance pneumography (IPG), frequency modulated continuous wave radar, and an acoustic breath sounds monitor were compared with the gold standard of capnography for their ability to detect RR in breaths per minute (breaths·min-1) in awake postoperative patients in the postanesthesia care unit. The Bland and Altman method for repeated measurements and mixed effect modelling was used to obtain bias and limits of agreement (LoA). Furthermore, the ability of the three devices to assist with correct treatment decisions was evaluated in Clarke Error Grids. RESULTS: Twenty patients were monitored for 1,203 min, with a median [interquartile range] of 61 [60-63] min per patient. The bias (98.9% LoA) were 0.1 (-7.9 to 7.9) breaths·min-1 for the acoustic monitor, -1.6 (-10.8 to 7.6) for the radar, and -1.9 (-13.1 to 9.2) for the IPG. The extent to which the monitors guided adequate or led to inadequate treatment decisions (determined by Clarke Error Grid analysis) differed significantly between the monitors (P = 0.011). Decisions were correct 96% of the time for acoustic, 95% of the time for radar, and 94% of the time for IPG monitoring devices. CONCLUSIONS: None of the studied devices (acoustic, IPG, and radar monitor) had LoA that were within our predefined (based on clinical judgement) limits of ± 2 breaths·min-1. The acoustic breath sound monitor predicted the correct treatment more often than the IPG and the radar device.

The incidence of postoperative respiratory complications: A retrospective analysis of cuffed vs uncuffed tracheal tubes in children 0-7 years of age.

BACKGROUND: The use of cuffed vs uncuffed endotracheal tubes in pediatric anesthesia is widely debated. This study aimed to investigate whether the use of cuffed vs uncuffed tubes is associated with an increased incidence of acute postoperative respiratory complications. METHODS: We retrospectively studied all children aged 0-7 years in which the trachea was intubated between September 28, 2006 and August 26, 2016 in a pediatric university hospital. Logistic regression analysis was performed to estimate the association between tube design (cuffed vs uncuffed) and the incidence of acute postoperative respiratory complications (stridor, wheezing, or dyspnea; desaturations ≤90%) in need of intervention (epinephrine, dexamethasone, nebulizers, supplementary oxygen, or reintubation), adjusting for potential confounders. RESULTS: In 5247 of 6796 cases (77%), a cuffed tube was used. Acute postoperative respiratory complications in need of intervention occurred in 334 cases (4.9%) and were less common after cuffed than after uncuffed tubes (N = 236, 4.5% vs N = 98, 6.3%, respectively, odds ratio 0.70; 95%CI 0.55-0.89). Desaturation occurred less often after cuffed tubes (cuffed: N = 1365, 26.0%; uncuffed: N = 512, 33.1%; OR: 0.71 (0.61-0.84)). After adjusting for confounders, there was no difference in acute postoperative respiratory complications between cuffed tubes and uncuffed tubes (OR 0.74; 95%CI 0.55-1.01). Subgroup analyses in various age groups did not show significant differences between the use of cuffed or uncuffed tubes. CONCLUSION: After adjustment for multiple confounders, the use of cuffed tubes was not associated with an increased incidence of acute respiratory complications in postanesthesia care unit.

Incidence of Artifacts and Deviating Values in Research Data Obtained from an Anesthesia Information Management System in Children.

BACKGROUND: Vital parameter data collected in anesthesia information management systems are often used for clinical research. The validity of this type of research is dependent on the number of artifacts. METHODS: In this prospective observational cohort study, the incidence of artifacts in anesthesia information management system data was investigated in children undergoing anesthesia for noncardiac procedures. Secondary outcomes included the incidence of artifacts among deviating and nondeviating values, among the anesthesia phases, and among different anesthetic techniques. RESULTS: We included 136 anesthetics representing 10,236 min of anesthesia time. The incidence of artifacts was 0.5% for heart rate (95% CI: 0.4 to 0.7%), 1.3% for oxygen saturation (1.1 to 1.5%), 7.5% for end-tidal carbon dioxide (6.9 to 8.0%), 5.0% for noninvasive blood pressure (4.0 to 6.0%), and 7.3% for invasive blood pressure (5.9 to 8.8%). The incidence of artifacts among deviating values was 3.1% for heart rate (2.1 to 4.4%), 10.8% for oxygen saturation (7.6 to 14.8%), 14.1% for end-tidal carbon dioxide (13.0 to 15.2%), 14.4% for noninvasive blood pressure (10.3 to 19.4%), and 38.4% for invasive blood pressure (30.3 to 47.1%). CONCLUSIONS: Not all values in anesthesia information management systems are valid. The incidence of artifacts stored in the present pediatric anesthesia practice was low for heart rate and oxygen saturation, whereas noninvasive and invasive blood pressure and end-tidal carbon dioxide had higher artifact incidences. Deviating values are more often artifacts than values in a normal range, and artifacts are associated with the phase of anesthesia and anesthetic technique. Development of (automatic) data validation systems or solutions to deal with artifacts in data is warranted.

Evaluating the impact of prediction models: lessons learned, challenges, and recommendations.

An important aim of clinical prediction models is to positively impact clinical decision making and subsequent patient outcomes. The impact on clinical decision making and patient outcome can be quantified in prospective comparative-ideally cluster-randomized-studies, known as 'impact studies'. However, such impact studies often require a lot of time and resources, especially when they are (cluster-)randomized studies. Before envisioning such large-scale randomized impact study, it is important to ensure a reasonable chance that the use of the prediction model by the targeted healthcare professionals and patients will indeed have a positive effect on both decision making and subsequent outcomes. We recently performed two differently designed, prospective impact studies on a clinical prediction model to be used in surgical patients. Both studies taught us new valuable lessons on several aspects of prediction model impact studies, and which considerations may guide researchers in their decision to conduct a prospective comparative impact study. We provide considerations on how to prepare a prediction model for implementation in practice, how to present the model predictions, and how to choose the proper design for a prediction model impact study.

Relationship Between Preoperative Evaluation Blood Pressure and Preinduction Blood Pressure: A Cohort Study in Patients Undergoing General Anesthesia.

BACKGROUND: For outcomes research where changes in intraoperative blood pressure are a possible causative factor, it is important to determine an appropriate source for a reference value. We studied to what extent preinduction blood pressure values in the operating room differ from those obtained during preoperative evaluation outside the operating room. METHODS: Cohort study including 4408 patients aged 60 years or older undergoing noncardiac surgery. The outcome was the difference between the preinduction mean blood pressure (MBP) and the MBP obtained during preoperative evaluation. A difference of ≥10 mm Hg was considered clinically relevant. A paired samples t test was used to estimate the difference. Linear regression was used to obtain estimates adjusted for patient characteristics, comorbidity, medications, type of surgery, and preoperative blood pressure. RESULTS: Complete data were available for 3660 (83%) patients. There were 2228 (61%) patients with a difference of ≥10 mm Hg between the preinduction and preoperative MBP. The overall mean difference between both MBPs was 11 mm Hg (95% confidence interval, 10-11) with important variability among individuals. Patients with higher preoperative MBP values had smaller differences. After adjusting for patient characteristics, comorbidity, medications, type of surgery, and preoperative blood pressure, the difference decreased an estimated 5.0 mm Hg (95% confidence interval, 4.7-5.4) for every increase of 10 mm Hg in preoperative MBP. Patient characteristics, comorbidity, type of surgery, or medication were not strongly associated with the difference. CONCLUSIONS: The average preinduction blood pressure was higher than the preoperative blood pressure. This difference between the measurements can be explained by stress-induced effects and regression to the mean. To define an optimal reference value for research purposes or to arrive at a clinical perioperative blood pressure target, one should consider that there is important variability both within and between patients.

A survey of the dose of inhalational agents used to maintain anaesthesia in infants.

BACKGROUND: Various animal studies suggest that currently used anaesthetics are toxic to the developing brain. Many reviews advise that the total anaesthetic drug exposure should be reduced but the dose usually used in clinical practice has not been clearly elucidated. OBJECTIVES: To provide an overview of the dose ranges currently used in clinical practice during the maintenance phase of anaesthesia in infants undergoing anaesthesia for noncardiac surgery and diagnostic procedures. DESIGN: A two-centre mixed prospective (London) and retrospective (Utrecht) observational cohort study. SETTING: Two independent tertiary paediatric referral centres in March and November 2013; Great Ormond Street Hospital (GOSH), London, United Kingdom and Wilhelmina Children's Hospital, University Medical Center Utrecht (UMCU), The Netherlands. PATIENTS: A total of 76 infants were included in the analysis, 38 infants from each hospital. METHODS: Patients from GOSH were matched by procedure, age and weight with patients from the UMCU. The end-tidal concentrations of the inhalational agents were investigated from anaesthetic charts during the maintenance phase and corrected for the age-specific minimal alveolar concentration (MAC), expressed as a percentage from the MAC (%MAC). RESULTS: Three different types of inhalational anaesthetics were used: sevoflurane, desflurane, isoflurane. The mean %MAC was 0.85. No significant differences in %MAC were found between GOSH and the UMCU (P = 0.329); the mean %MAC in GOSH was 0.87 and in the UMCU was 0.82. There was a significant increase in the %MAC in relation to age (slope = 0.036 MAC month, P < 0.001). Of all patients, 75% had an end-tidal concentration lower than 1 MAC. There was no significant effect of the use of analgesia on the end-tidal concentration of inhalational anaesthetics (P = 0.366). CONCLUSION: The concentration of inhalational anaesthetics in %MAC increased with age and was lowest in neonates. Most young infants received inhalational anaesthetics at a concentration below 1 MAC, which accords with current guidance to minimise anaesthetic drug exposure but may have unintended consequences.

Association between Intraoperative Hypotension and Myocardial Injury after Vascular Surgery.

BACKGROUND: Postoperative myocardial injury occurs frequently after noncardiac surgery and is strongly associated with mortality. Intraoperative hypotension (IOH) is hypothesized to be a possible cause. The aim of this study was to determine the association between IOH and postoperative myocardial injury. METHODS: This cohort study included 890 consecutive patients aged 60 yr or older undergoing vascular surgery from two university centers. The occurrence of myocardial injury was assessed by troponin measurements as part of a postoperative care protocol. IOH was defined by four different thresholds using either relative or absolute values of the mean arterial blood pressure based on previous studies. Either invasive or noninvasive blood pressure measurements were used. Poisson regression analysis was used to determine the association between IOH and postoperative myocardial injury, adjusted for potential clinical confounders and multiple comparisons. RESULTS: Depending on the definition used, IOH occurred in 12 to 81% of the patients. Postoperative myocardial injury occurred in 131 (29%) patients with IOH as defined by a mean arterial pressure less than 60 mmHg, compared with 87 (20%) patients without IOH (P = 0.001). After adjustment for potential confounding factors including mean heart rates, a 40% decrease from the preinduction mean arterial blood pressure with a cumulative duration of more than 30 min was associated with postoperative myocardial injury (relative risk, 1.8; 99% CI, 1.2 to 2.6, P < 0.001). Shorter cumulative durations (less than 30 min) were not associated with myocardial injury. Postoperative myocardial infarction and death within 30 days occurred in 26 (6%) and 17 (4%) patients with IOH as defined by a mean arterial pressure less than 60 mmHg, compared with 12 (3%; P = 0.08) and 15 (3%; P = 0.77) patients without IOH, respectively. CONCLUSIONS: In elderly vascular surgery patients, IOH defined as a 40% decrease from the preinduction mean arterial blood pressure with a cumulative duration of more than 30 min was associated with postoperative myocardial injury.

Barriers and facilitators perceived by physicians when using prediction models in practice.

OBJECTIVES: Prediction models may facilitate risk-based management of health care conditions. In a large cluster-randomized trial, presenting calculated risks of postoperative nausea and vomiting (PONV) to physicians (assistive approach) increased risk-based management of PONV. This increase did not improve patient outcome-that is, PONV incidence. This prompted us to explore how prediction tools guide the decision-making process of physicians. STUDY DESIGN AND SETTING: Using mixed methods, we interviewed eight physicians to understand how predicted risks were perceived by the physicians and how they influenced decision making. Subsequently, all 57 physicians of the trial were surveyed for how the presented risks influenced their perceptions. RESULTS: Although the prediction tool made physicians more aware of PONV prevention, the physicians reported three barriers to use predicted risks in their decision making. PONV was not considered an outcome of utmost importance; decision making on PONV prophylaxis was mostly intuitive rather than risk based; prediction models do not weigh benefits and risks of prophylactic drugs. CONCLUSION: Combining probabilistic output of the model with their clinical experience may be difficult for physicians, especially when their decision-making process is mostly intuitive. Adding recommendations to predicted risks (directive approach) was considered an important step to facilitate the uptake of a prediction tool.

Reporting critical incidents in a tertiary hospital: a historical cohort study of 110,310 procedures.

PURPOSE: Investigation of adverse events associated with anesthetic procedures is a method of quality control that identifies topics to improve clinical care and patient safety. Most research to date has been based on closed claim registries and anonymous reports which have specific limitations. Therefore, to evaluate a hospital's reporting system, the present study was designed to describe critical incidents that anesthesiologists voluntarily and non-anonymously reported through an anesthesia information management system. METHODS: This is a historical observational cohort study on patients (age > 18 yr) undergoing anesthetic procedures in a tertiary referral hospital. A 20-item list of complications, as developed by the Netherlands Society of Anesthesiologists, was prospectively completed for each procedure. All critical incidents registered in the anesthesia information management system were then reclassified into 95 different critical incidents in a reproducible way. RESULTS: There were 110,310 procedures performed in 65,985 patients, and after excluding 158 reports that did not depict a critical incident, 3,904 critical incidents in 3,807 (3.5%) anesthetic procedures remained. Technical difficulties with regional anesthesia (n = 445; 40 per 10,000 anesthetics; 95% confidence interval [CI], 36 to 44), hypotension (n = 432; 39 per 10,000 anesthetics; 95% CI, 35 to 43), and unexpected difficult intubation (n = 216; 20 per 10,000 anesthetics; 95% CI, 18 to 23) were the most frequently documented critical incidents. CONCLUSION: Accurate measurement and monitoring of critical incidents is crucial for patient safety. Despite the risk of underreporting and probable misclassification of manual reporting systems, our results give a comprehensive overview on the occurrence of voluntarily reported anesthesia-related critical incidents. This overview can direct development of a new reporting system and preventive strategies to decrease the future occurrence of critical incidents.

Anesthesia-related critical incidents in the perioperative period in children; a proposal for an anesthesia-related reporting system for critical incidents in children.

BACKGROUND: The incidence, type and severity of anesthesia-related critical incidents during the perioperative phase has been investigated less in children than in adults. AIM: The aim of the study was to identify and analyze anesthesia-related critical incidents in children to identify areas to improve current clinical practice, and to propose a specialized anesthesia-related critical incidence registration for children. METHOD: All reported pediatric anesthesia-related critical incidents reported on a voluntary reporting based on a 20-item complication list of the Dutch Society of Anesthesiology between January 2007 and August 2013 were analyzed. An anesthesia-related critical incident was defined as 'any incident that affected, or could have affected, the safety of the patient while under the care of an anesthetist'. As the 20-item complications list was too crude for detailed analyses, all critical incidents were reclassified into the more detailed German classification lists with the adjustment of specific items for children (in total 10 categories with 101 different subcategories). RESULTS: During the 6-year period, a total of 1214 critical incidents were reported out of 35 190 anesthetics (cardiac and noncardiac anesthesia cases). The most frequently reported incidents (46.5%) were related to the respiratory system. Infants <1 year, children with ASA physical status III and IV, and emergency procedures had a higher rate of adverse incidents. CONCLUSION: Respiratory events were the most reported commonly critical incidents in children. Both the Dutch and German existing lists of critical incident definitions appeared not to be sufficient for accurate classification in children. The present list can be used for a new registration system for critical incidents in pediatric anesthesia.

Impact of risk assessments on prophylactic antiemetic prescription and the incidence of postoperative nausea and vomiting: a cluster-randomized trial.

BACKGROUND: Clinical prediction models have been shown to have moderate sensitivity and specificity, yet their use will depend on implementation in clinical practice. The authors hypothesized that implementation of a prediction model for postoperative nausea and vomiting (PONV) would lower the PONV incidence by stimulating anesthesiologists to administer more "risk-tailored" prophylaxis to patients. METHODS: A single-center, cluster-randomized trial was performed in 12,032 elective surgical patients receiving anesthesia from 79 anesthesiologists. Anesthesiologists were randomized to either exposure or nonexposure to automated risk calculations for PONV (without patient-specific recommendations on prophylactic antiemetics). Anesthesiologists who treated less than 50 enrolled patients were excluded during the analysis to avoid too small clusters, yielding 11,613 patients and 57 anesthesiologists (intervention group: 5,471 and 31; care-as-usual group: 6,142 and 26). The 24-h incidence of PONV (primary outcome) and the number of prophylactic antiemetics administered per patient were studied for risk-dependent differences between allocation groups. RESULTS: There were no differences in PONV incidence between allocation groups (crude incidence intervention group 41%, care-as-usual group 43%; odds ratio, 0.97; 95% CI, 0.87-1.1; risk-dependent odds ratio, 0.92; 95% CI, 0.80-1.1). Nevertheless, intervention-group anesthesiologists administered more prophylactic antiemetics (rate ratio, 2.0; 95% CI, 1.6-2.4) and more risk-tailored than care-as-usual-group anesthesiologists (risk-dependent rate ratio, 1.6; 95% CI, 1.3-2.0). CONCLUSIONS: Implementation of a PONV prediction model did not reduce the PONV incidence despite increased antiemetic prescription in high-risk patients by anesthesiologists. Before implementing prediction models into clinical practice, implementation studies that include patient outcomes as an endpoint are needed.

Incidence of intraoperative hypoxemia in children in relation to age.

BACKGROUND: Although respiratory problems are by far the most frequent complications of pediatric anesthesia, there are currently no reliable data on the incidence of perioperative hypoxemia in children. Most studies investigating the incidence of pediatric respiratory complications were based on self-report. METHODS: We studied the incidence of intraoperative hypoxemia as well as that of pulse oximeter artifacts prospectively in 575 pediatric noncardiac surgery patients aged between 0 and 16 years operated in a tertiary pediatric university hospital. Subsequently, the incidence of intraoperative hypoxemia was determined retrospectively in 8277 patients registered in an anesthesia information management system (AIMS) of the same hospital. RESULTS: In the prospective cohort, at least 1 episode of oxygen saturation (Spo2) ≤ 90% for at least 1 minute occurred in 69 of 575 cases (12%; 95% confidence interval [CI], 9%-15%). Furthermore, in 35 of 575 (6%; 95% CI, 4%-8%) cases at least 1 true hypoxemic event was observed. In total, 117 episodes of Spo2 ≤ 90% were observed in the prospective study, of which 3 of 117 could not be specified and 67 of 114 (54%; 95% CI, 42%-65%) episodes were classified as true hypoxemia. False-positive low Spo2 values were mainly caused by dislodgment of the pulse oximeter. In the retrospective analysis, Spo2 ≤ 90% and Spo2 ≤ 80% for at least 1 minute were documented in the AIMS in 18% (95% CI, 17%-19%) and 7.5% (95% CI, 7%-8%) of the cases, respectively; 31 and 10 episodes per 100 cases, respectively. The incidence of hypoxemia increased in younger age groups: Spo2 ≤ 90% for at least 1 minute occurred in 56% (95% CI, 49%-63%) of neonates (170 episodes per 100 cases). CONCLUSIONS: The incidence of intraoperative hypoxemia increased with younger age, with the highest incidence in neonates. Because of the high artifact rate, unvalidated pulse oximeter data in AIMS should be interpreted with caution because only up to 65% of all hypoxemic episodes recorded during pediatric anesthesia were caused by true hypoxia.

Artifacts in research data obtained from an anesthesia information and management system.

PURPOSE: Artifacts in anesthesia information management system (AIMS) databases may influence research results. Filtering during data capturing can prevent artifacts from being stored. In this prospective study, we assessed the reliability of AIMS data by determining the incidence of artifactual values stored in the AIMS. METHODS: Vital parameter values regarding 86 surgical patients were collected in the AIMS both manually and automatically after filtering using the median value per minute. The percentage of artifactual values with a 95% confidence interval (CI) was calculated for each parameter. Secondary outcomes included the number of values that deviated from a predefined baseline, the percentage of these deviations that were caused by artifacts, the number of episodes across which these artifacts were distributed, and the most common causes of artifacts. RESULTS: Altogether, 9,534 min of anesthesia time were recorded. The overall percentages of artifacts were: 0.0 for heart rate (95% CI: 0.0 to 0.1), 0.3 for oxygen saturation (95% CI: 0.2 to 0.4), 4.7 for ST-segment (95% CI: 4.3 to 5.2), 2.3 for noninvasive blood pressure values (95% CI: 1.8 to 2.9), and 14 for invasive blood pressure values (95% CI: 12 to 15). Artifacts as a percentage of deviations from baseline were: 1.6 for heart rate (95% CI: 0.4 to 5.7), 24 for saturation (95% CI: 18 to 32), 83 for ST-segment (95% CI: 76 to 87), 3.3 for noninvasive blood pressure values (95% CI: 2.5 to 87), and 27 for invasive blood pressure values (95% CI: 24 to 31). CONCLUSIONS: Storing a median value per minute to filter capturing of vital parameter values in an AIMS database provides reliable data for heart rate and oxygen saturation and acceptable reliability for noninvasive blood pressure data. Knowledge about the method of artifact filtering is essential in studies using AIMS data.

Preoperative testing in noncardiac surgery patients: a survey amongst European anaesthesiologists.

CONTEXT: Previous surveys of the current practice of preoperative assessment within different countries have shown that there is much variation between different hospitals. OBJECTIVE: The aim of the present study was to document the current clinical practice of preoperative testing for noncardiac surgery in Europe. We also wanted to assess the opinion of anaesthesiologists on eliminating routine preoperative testing. DESIGN: Cross-sectional study. SETTING: Anaesthesiologists from 17 different countries in Europe were surveyed between May and July 2009. PARTICIPANTS: Anaesthesiologists registered with a national anaesthesiology society represented in the European Society of Anaesthesiology. MAIN OUTCOME MEASURES: Indications for preoperative tests in different countries within Europe. RESULTS: We received 354 completed questionnaires from 17 countries, all from different hospitals. In most countries, the anaesthesiologist has the final responsibility of performing preoperative evaluation (83%) and a preoperative assessment clinic is commonplace (95%). There is a remarkable variation in the way tests are ordered in different practices and also between different countries. About half of the anaesthesiologists indicated that they order preoperative tests in accordance with guidelines. Most respondents (86%) indicated that they would support moves towards a reduction in preoperative testing, but 44% cited patient safety as the main concern if routine testing was eliminated. CONCLUSION: Our survey shows a large variety in organisation and practice of preoperative evaluation throughout Europe. This practice is frequently not in accordance with guideline recommendations. Our survey confirms that there is a shift towards selective testing and also that the majority of respondents support a move towards reducing preoperative testing.

Adaptation of clinical prediction models for application in local settings.

BACKGROUND: When planning to use a validated prediction model in new patients, adequate performance is not guaranteed. For example, changes in clinical practice over time or a different case mix than the original validation population may result in inaccurate risk predictions. OBJECTIVE: To demonstrate how clinical information can direct updating a prediction model and development of a strategy for handling missing predictor values in clinical practice. METHODS: A previously derived and validated prediction model for postoperative nausea and vomiting was updated using a data set of 1847 patients. The update consisted of 1) changing the definition of an existing predictor, 2) reestimating the regression coefficient of a predictor, and 3) adding a new predictor to the model. The updated model was then validated in a new series of 3822 patients. Furthermore, several imputation models were considered to handle real-time missing values, so that possible missing predictor values could be anticipated during actual model use. RESULTS: Differences in clinical practice between our local population and the original derivation population guided the update strategy of the prediction model. The predictive accuracy of the updated model was better (c statistic, 0.68; calibration slope, 1.0) than the original model (c statistic, 0.62; calibration slope, 0.57). Inclusion of logistical variables in the imputation models, besides observed patient characteristics, contributed to a strategy to deal with missing predictor values at the time of risk calculation. CONCLUSIONS: Extensive knowledge of local, clinical processes provides crucial information to guide the process of adapting a prediction model to new clinical practices.

Intrapartum epidural analgesia and ST analysis of the fetal electrocardiogram.

OBJECTIVE: To evaluate the influence of intrapartum epidural analgesia on the occurrence of ST events of the fetal ECG. DESIGN: Nested case-control study. SETTING: Single-centre academic hospital in the Netherlands. POPULATION: Laboring women with a high-risk singleton pregnancy in cephalic position beyond 36 weeks of gestation. METHODS: Data of 72 women who received epidural analgesia using bupivacaine combined with sufentanil and 72 control women were collected and analyzed. The moment of epidural infusion was defined as t(0) . In the control group, t(0) was defined by matching dilatation in centimeters. STAN registrations from one hour before until two hours after t(0) were classified, and the numbers and types of ST events were recorded and judged according to the STAN clinical guidelines. T/QRS ratios were collected from one hour before t(0) until two hours after t(0) , and differences were compared between the two groups. MAIN OUTCOME MEASURES: Numbers and types of ST events and mean T/QRS ratios before and after t(0). RESULTS: There were no significant differences between cases and control women regarding the numbers of ST events, types of ST events and whether they were significant (intervention advised) or not. Correction for outliers (three cases and three control women) did not change the results. Differences of T/QRS ratios before and after t(0) were comparable between cases and control women. CONCLUSIONS: Epidural analgesia has no effect on the numbers or types of ST events when using ST analysis of the fetal ECG.