Opportunities and barriers for prehospital emergency medical services research in the Netherlands; results of a mixed-methods consensus study.

INTRODUCTION: Quality improvement in prehospital emergency medical services (EMS) can only be achieved by high-quality research and critical appraisal of current practices. This study examines current opportunities and barriers in EMS research in the Netherlands. METHODS: This mixed-methods consensus study consisted of three phases. The first phase consisted of semi-structured interviews with relevant stakeholders. Thematic analysis of qualitative data derived from these interviews was used to identify main themes, which were subsequently discussed in several online focus groups in the second phase. Output from these discussions was used to shape statements for an online Delphi consensus study among relevant stakeholders in EMS research. Consensus was met if 80% of respondents agreed or disagreed on a particular statement. RESULTS: Forty-nine stakeholders participated in the study; qualitative thematic analysis of the interviews and focus group discussions identified four main themes: (1) data registration and data sharing, (2) laws and regulations, (3) financial aspects and funding, and (4) organization and culture. Qualitative data from the first two phases of the study were used to construct 33 statements for an online Delphi study. Consensus was reached on 21 (64%) statements. Eleven (52%) of these statements pertained to the storage and use of EMS patient data. CONCLUSION: Barriers for prehospital EMS research in the Netherlands include issues regarding the use of patient data, privacy and legislation, funding and research culture in EMS organizations. Opportunities to increase scientific productivity in EMS research include the development of a national strategy for EMS data and the incorporation of EMS topics in research agendas of national medical professional associations.

Measuring Mitochondrial Oxygen Tension during Red Blood Cell Transfusion in Chronic Anemia Patients: A Pilot Study.

In light of the associated risks, the question has been raised whether the decision to give a blood transfusion should solely be based on the hemoglobin level. As mitochondria are the final destination of oxygen transport, mitochondrial parameters are suggested to be of added value. The aims of this pilot study were to investigate the effect of a red blood cell transfusion on mitochondrial oxygenation as measured by the COMET device in chronic anemia patients and to explore the clinical usability of the COMET monitor in blood transfusion treatments, especially the feasibility of performing measurements in an outpatient setting. To correct the effect of volume load on mitochondrial oxygenation, a red blood cell transfusion and a saline infusion were given in random order. In total, 21 patients were included, and this resulted in 31 observations. If patients participated twice, the order of infusion was reversed. In both the measurements wherein a blood transfusion was given first and wherein 500 mL of 0.9% saline was given first, the median mitochondrial oxygen tension decreased after red blood cell transfusion. The results of this study have strengthened the need for further research into the effect of blood transfusion tissue oxygenation and the potential role of mitochondrial parameters herein.

Monitoring of mitochondrial oxygen tension in the operating theatre: An observational study with the novel COMET® monitor.

INTRODUCTION: The newly introduced Cellular Oxygen METabolism (COMET®) monitor enables the measurement of mitochondrial oxygen tension (mitoPO2) using the protoporphyrin IX triplet state lifetime technique (PpIX-TSLT). This study aims to investigate the feasibility and applicability of the COMET® measurements in the operating theatre and study the behavior of the new parameter mitoPO2 during stable operating conditions. METHODS: In this observational study mitochondrial oxygenation was measured in 20 patients during neurosurgical procedures using the COMET® device. Tissue oxygenation and local blood flow were measured by the Oxygen to See (O2C). Primary outcomes included mitoPO2, skin temperature, mean arterial blood pressure, local blood flow and tissue oxygenation. RESULTS: All patients remained hemodynamically stable during surgery. Mean baseline mitoPO2 was 60 ± 19 mmHg (mean ± SD) and mean mitoPO2 remained between 40-60 mmHg during surgery, but tended to decrease over time in line with increasing skin temperature. CONCLUSION: This study presents the feasibility of mitochondrial oxygenation measurements as measured by the COMET® monitor in the operating theatre and shows the parameter mitoPO2 to behave in a stable and predictable way in the absence of notable hemodynamic alterations. The results provide a solid base for further research into the added value of mitochondrial oxygenation measurements in the perioperative trajectory.

Intravenous lidocaine attenuates distention of the optical nerve sheath, a correlate of intracranial pressure, during endotracheal intubation.

BACKGROUND: By preventing hypoxia and hypercapnia, advanced airway management can save lives among patients with traumatic brain injury. During endotracheal intubation (ETI), tracheal stimulation causes an increase in intracranial pressure (ICP), which may impair brain perfusion. It has been suggested that intravenous lidocaine might attenuate this ICP response. We hypothesized that adding lidocaine to the standard induction medication for general anesthesia might reduce the ICP response to ETI. Here, we measured the optical nerve sheath diameter (ONSD) as a correlate of ICP and evaluated the effect of intravenous lidocaine on ONSD during and after ETI in patients undergoing anesthesia. METHODS: This double-blinded, randomized placebo-controlled trial included 60 patients with American Society of Anesthesiologists I or II physical status that were scheduled for elective surgery under general anesthesia. In addition to the standard anesthesia medication, 30 subjects received 1.5 mg/kg 1% lidocaine (0.15 mL/kg, ONSD lidocaine) and 30 received 0.15 mL/kg 0.9% NaCl (ONSD placebo). ONSDs were measured with ultrasound on the left eye, before (T0), during (T1), and 4 times after ETI (T2-5 at 5-min intervals). RESULTS: Compared to placebo, lidocaine did not significantly affect the baseline ONSD after anesthesia induction measured at T0. During ETI, the ONSD lidocaine was significantly smaller (ß=-0.24 mm P=0.022) than the ONSD placebo. At T4 and T5, the ONSD placebo increased steadily, up to 20 min after ETI, but the ONSD lidocaine tended to return to baseline levels. CONCLUSIONS: We found that the ONSD was distended during and after ETI in anesthetized patients, and intravenous lidocaine attenuated this effect.

Observer Variability as a Determinant of Measurement Error of Ultrasonographic Measurements of the Optic Nerve Sheath Diameter: A Systematic Review.

BACKGROUND: Ultrasonographic measurements of the diameter of the sheath of the optic nerve can be used to assess intracranial pressure indirectly. These measurements come with measurement error. OBJECTIVE: Our aim was to estimate observer's measurement error as a determinant of ultrasonographic measurement variability of the optic nerve sheath diameter. METHODS: A systematic search of the literature was conducted in Embase, Medline, Web of Science, the Cochrane Central Register of Trials, and the first 200 articles of Google Scholar up to April 19, 2021. Inclusion criteria were the following: healthy adults, B-mode ultrasonography, and measurements 3 mm behind the retina. Studies were excluded if standard error of measurement could not be calculated. Nine studies featuring 389 participants (median 40; range 15-100) and 22 observers (median 2; range 1-4) were included. Standard error of measurement and minimal detectable differences were calculated to quantify observer variability. Quality and risk of bias were assessed with the Guidelines for Reporting Reliability and Agreement Studies. RESULTS: The standard error of measurement of the intra- and interobserver variability had a range of 0.10-0.41 mm and 0.14-0.42 mm, respectively. Minimal detectable difference of a single observer was 0.28-1.1 mm. Minimal detectable difference of multiple observers (range 2-4) was 0.40-1.1 mm. Quality assessment showed room for methodological improvement of included studies. CONCLUSIONS: The standard errors of measurement and minimal detectable differences of ultrasonographic measurements of the optic nerve sheath diameter found in this review with healthy participants indicate caution should be urged when interpreting results acquired with this measurement method in clinical context.

Methylprednisolone in Pediatric Cardiac Surgery: Is There Enough Evidence?

Corticosteroids have been used to decrease the inflammatory response to cardiac surgery and cardiopulmonary bypass in children for decades. Sparse information is present concerning the pharmacokinetics and pharmacodynamics of corticosteroids in the context of pediatric cardiac surgery. There is large interindividual variability in plasma concentrations, with indications for a larger volume of distribution in neonates compared to other age groups. There is ample evidence that perioperative use of MP leads to a decrease in pro-inflammatory mediators and an increase in anti-inflammatory mediators, with no difference in effect between doses of 2 and 30 mg/kg. No differences in inflammatory mediators have been shown between different times of administration relative to the start of surgery in various studies. MP has been shown to have a beneficial effect in certain subgroups of patients but is also associated with side effects. In lower risk categories, the balance between risk and benefit may be shifted toward risk. There is limited information on short- to medium-term outcome (mortality, low cardiac output syndrome, duration of mechanical ventilation, length of stay in the intensive care unit or the hospital), mostly from underpowered studies. No information on long-term outcome, such as neurodevelopmental outcome, is available. MP may provide a small benefit that is easily abolished by patient characteristics, surgical techniques, and perfusion management. The lack of evidence leads to large differences in practice between and within countries, and even within hospitals, so there is a need for adequately powered randomized studies.

Methylprednisolone Plasma Concentrations During Cardiac Surgery With Cardiopulmonary Bypass in Pediatric Patients.

Introduction: To our knowledge, methylprednisolone pharmacokinetics and plasma concentrations have not been comprehensively investigated in children with congenital heart disease undergoing cardiac surgery with cardiopulmonary bypass. It is unknown whether there is a significant influence of cardiopulmonary bypass on the plasma concentrations of methylprednisolone and whether this may be an explanation for the limited reported efficacy of steroid administration in cardiac surgery with cardiopulmonary bypass. Methods: The study was registered in the Dutch Trial Register (NTR3579; https://www.trialregister.nl/trial/3428). Methylprednisolone 30 mg/kg was administered as an intravenous bolus after induction of anesthesia. Methylprednisolone concentration was measured with liquid chromatography tandem mass spectrometry and analyzed using linear mixed-effects modeling. Results: Thirty-nine patients were included in the study, of which three were excluded. There was an acute decrease in observed methylprednisolone plasma concentration on initiation of cardiopulmonary bypass (median = 26.8%, range = 13.9-48.14%, p < 0.001). We found a lower intercept (p = 0.02), as well as a less steep slope of the model predicted methylprednisolone concentration vs. time curve for neonates (p = 0.048). A lower intercept (p = 0.01) and a less steep slope (p = 0.0024) if the volume of cell saver blood processed was larger than 91 ml/kg were also found. Discussion: We report similar methylprednisolone plasma concentrations as earlier studies performed in children undergoing cardiopulmonary bypass, and we confirmed the large interindividual variability in achieved methylprednisolone plasma concentrations with weight-based methylprednisolone administration. A larger volume of distribution and a lower clearance of methylprednisolone for neonates were suggested. The half-life of methylprednisolone in our study was calculated to be longer than 6 h for neonates, 4.7 h for infants, 3.6 h for preschool children and 4.7 h for school children. The possible influence of treatment of pulmonary hypertension with sildenafil and temperature needs to be investigated further.

Current state of noninvasive, continuous monitoring modalities in pediatric anesthesiology.

PURPOSE OF REVIEW: The last decades, anesthesia has become safer, partly due to developments in monitoring. Advanced monitoring of children under anesthesia is challenging, due to lack of evidence, validity and size constraints. Most measured parameters are proxies for end organ function, in which an anesthesiologist is actually interested. Ideally, monitoring should be continuous, noninvasive and accurate. This present review summarizes the current literature on noninvasive monitoring in noncardiac pediatric anesthesia. RECENT FINDINGS: For cardiac output (CO) monitoring, bolus thermodilution is still considered the gold standard. New noninvasive techniques based on bioimpedance and pulse contour analysis are promising, but require more refining in accuracy of CO values in children. Near-infrared spectroscopy is most commonly used in cardiac surgery despite there being no consensus on safety margins. Its place in noncardiac anesthesia has yet to be determined. Transcutaneous measurements of blood gases are used mainly in the neonatal intensive care unit, and is finding its way to the pediatric operation theatre. Especially CO2 measurements are accurate and useful. SUMMARY: New techniques are available to assess a child's hemodynamic and respiratory status while under anesthesia. These new monitors can be used as complementary tools together with standard monitoring in children, to further improve perioperative safety.

Intrathecal hydrophilic opioids for abdominal surgery: a meta-analysis, meta-regression, and trial sequential analysis.

BACKGROUND: Intrathecal hydrophilic opioids decrease systemic opioid consumption after abdominal surgery and potentially facilitate enhanced recovery. A meta-analysis is needed to quantify associated risks and benefits. METHODS: A systematic search was performed to find RCTs investigating intrathecal hydrophilic opioids in abdominal surgery. Caesarean section and continuous regional or neuraxial techniques were excluded. Several subgroup analyses were prespecified. A conventional meta-analysis, meta-regression, trial sequential analysis, and provision of GRADE scores were planned. RESULTS: The search yielded 40 trials consisting of 2500 patients. A difference was detected in 'i.v. morphine consumption' at Day 1 {mean difference [MD] -18.4 mg, (95% confidence interval [CI]: -22.3 to -14.4)} and Day 2 (MD -25.5 mg [95% CI: -30.2 to -20.8]), pain scores at Day 1 in rest (MD -0.9 [95% CI: -1.1 to -0.7]) and during movement (MD -1.2 [95% CI: -1.6 to -0.8]), length of stay (MD -0.2 days [95% CI: -0.4 to -0.1]) and pruritus (relative risk 4.3 [95% CI: 2.5-7.5]) but not in nausea or sedation. A difference was detected for respiratory depression (odds ratio 5.5 [95% CI: 2.1-14.2]) but not when two small outlying studies were excluded (odds ratio 1.4 [95% CI: 0.4-5.2]). The level of evidence was graded as high for morphine consumption, in part because the required information size was reached. CONCLUSIONS: This study showed important opioid-sparing effects of intrathecal hydrophilic opioids. Our data suggest a dose-dependent relationship between the risk of respiratory depression and the dose of intrathecal opioids. Excluding two high-dose studies, intrathecal opioids have a comparable incidence of respiratory depression as the control group. CLINICAL TRIAL REGISTRATION: PROSPERO-registry: CRD42018090682.

Immediate postoperative high-sensitivity troponin T concentrations and long-term patient-reported health-related quality of life: A prospective cohort study.

BACKGROUND: Myocardial injury after noncardiac surgery is associated with mortality and major adverse postoperative cardiovascular events. The effect of postoperative troponin concentrations on patient-reported health-related quality of life (HRQoL) is unknown. OBJECTIVE: The study examined the association between immediate postoperative troponin concentrations and self-reported HRQoL 1 year after surgery. DESIGN: Prospective cohort study. SETTING: Single-centre tertiary care hospital in the Netherlands between July 2012 and 2015. PATIENTS: Patients aged at least 60 years undergoing moderate and major noncardiac surgery. INTERVENTION: None. MAIN OUTCOME MEASURES: HRQoL total score was assessed with the EuroQol five-dimensional questionnaire. Tobit regression analysis was used to determine the association between postoperative troponin concentrations and 1-year HRQoL. Peak high-sensitivity troponin T values were divided into four categories: less than 14, 14 to 49, 50 to 149 and at least 150 ng l. RESULTS: A total of 3085 patients with troponin measurements were included. 2634 (85.4%) patients were alive at 1-year follow-up of whom 1297 (49.2%) returned a completed questionnaire. The median score for HRQoL was 0.82 (0.85, 0.81, 0.77 and 0.71 per increasing troponin category). Multivariable analysis revealed betas of -0.06 [95% confidence interval (CI) -0.09 to -0.02], -0.11 (95% CI -0.18 to -0.04) and -0.18 (95% CI -0.29 to -0.07) for troponin levels of 14 to 49, 50 to 149 and at least 150 ng l when compared with values less than 14 ng l. Other independent predictors for lower HRQoL were chronic obstructive pulmonary disease, female sex, peripheral arterial disease and increasing age. CONCLUSION: Higher levels of postoperative troponin measured immediately after surgery were independently associated with lower self-reported HRQoL total score at 1-year follow-up.

Efficiency and efficacy of planning and care on a post-anesthesia care unit: a retrospective cohort study.

BACKGROUND: In the post-anesthesia care unit in our hospital, selected postoperative patients receive care from anesthesiologists and nursing staff if these patients require intensive hemodynamic monitoring or treatment to stabilize vital functions (e.g., vasopressor use and mechanical ventilation support) during a one-night admission. We investigated the agreement between elective preoperative planning for post-anesthesia care unit admission and the postoperative reality, along with the consequences of planning failures. METHODS: Data from records for 479 consecutive patients from June 1 to November 30, 2014, in a tertiary referral hospital were reviewed and analyzed. All patients admitted to PACU were included, along with patients scheduled to be referred to PACU but ultimately transferred to another ward. The primary outcome was the efficiency of planning PACU admission for elective patients. Secondary outcomes included secondary admissions to PACU or the intensive care unit (ICU) and 30-day morbidity and mortality. RESULTS: Of the 479 included patients, 342 (71%) were admitted per preoperative planning. Five patients (1%) needed cardiopulmonary resuscitation, and six (1%) did not survive the follow-up period. Patients admitted to PACU because of a shortage of beds in the ICU had the highest readmission (20%) and mortality rates (20%) (P = 0.01). CONCLUSIONS: Preoperative planning for PACU admission was off-target for 29%. However, efficient care always takes precedence over efficient planning. In particular, downgrading patients to PACU because of a shortage of beds in the ICU was associated with a mortality increase.

In Vitro Recovery of Sufentanil, Midazolam, Propofol, and Methylprednisolone in Pediatric Cardiopulmonary Bypass Systems.

OBJECTIVES: To evaluate in vitro drug recovery in cardiopulmonary bypass (CPB) systems used for pediatric cardiac surgery. DESIGN: Observational in vitro study. SETTING: Single-center university hospital. PARTICIPANTS: In vitro CPB systems used for pediatric cardiac surgery. INTERVENTIONS: Three full neonatal, infant, and pediatric CPB systems were primed according to hospital protocol and kept running for 6 hours. Midazolam, propofol, sufentanil, and methylprednisolone were added to the venous side of the systems in doses commonly used for induction of general anesthesia. Blood samples were taken from the postoxygenator side of the circuit immediately after injection of the drugs and after 2, 5, 7, 10, 30, 60, 180, and 300 minutes. MEASUREMENTS AND MAIN RESULTS: Linear mixed model analyses were performed to assess the relationship between log-transformed drug concentration (dependent variable) and type of CPB system and sample time point (independent variables). The mean percentage of drug recovery after 60 and 180 minutes compared with T1 was 41.7% (95% confidence interval [CI] 35.9-47.4) and 23.0% (95% CI 9.2-36.8) for sufentanil, 87.3% (95% CI 64.9-109.7) and 82.0% (95% CI 64.6-99.4) for midazolam, 41.3% (95% CI 15.5-67.2) and 25.0% (95% CI 4.7-45.3) for propofol, and 119.3% (95% CI 101.89-136.78) and 162.0% (95% CI 114.09-209.91) for methylprednisolone, respectively. CONCLUSIONS: The present in vitro experiment with neonatal, infant, and pediatric CPB systems shows a variable recovery of routinely used drugs with significant differences between drugs, but not between system categories (with the exception of propofol). The decreased recovery of mainly sufentanil and propofol could lead to suboptimal dosing of patients during cardiac surgery with CPB.

Hyperlactatemia After Intracranial Tumor Surgery Does Not Affect 6-Month Survival: A Retrospective Case Series.

BACKGROUND: Patients undergoing neurosurgery frequently exhibit hyperlactatemia. The aim of this study was to identify factors associated with hyperlactatemia and assess how hyperlactatemia impacts survival and hospital length of stay after intracranial tumor surgery. MATERIALS AND METHODS: This retrospective cohort study included 496 adult patients that underwent surgery between January 1, 2014 and December 31, 2015. We evaluated patient characteristics, surgery characteristics, pH, lactate, and blood glucose from blood samples collected on admission to the high-dependency unit and the morning after surgery, and 6-month outcome data. RESULTS: Hyperlactatemia (>2.0 mmol/L) occurred in >50% of patients, but only 7.7% had acidosis. Postoperative hyperlactatemia was not correlated with 6-month survival (P=0.987), but was correlated with (median [interquartile range]) longer hospital stays (6 [4 to 8.5] d vs. 5 [4 to 8] d; P=0.006), longer surgery duration (4:53 [4:01 to 6:18] h:min vs. 4:28 [3:33 to 5:53] h:min; P=0.001), higher dexamethasone dose (16 [16 to 35] mg vs. 16 [16 to 20] mg; P<0.001), and higher blood glucose concentration (8.4 [7.5 to 9.6] mmol/L vs. 8.0 [7.1 to 8.9] mmol/L; P<0.001). Patients that received total intravenous anesthesia developed hyperlactatemia less frequently than those that received balanced anesthesia with inhalational agents (48.4% vs. 61.5%, P=0.008). Hyperlactatemia was not associated with increased postoperative neurological deficits or the need for rehabilitation therapy. CONCLUSIONS: Hyperlactatemia was common after intracranial tumor surgery. It did not influence 6-month outcomes but was associated with longer hospital length of stay. Several potential causative factors for hyperlactatemia were identified.

The effect of midazolam as premedication on the quality of postoperative recovery after laparotomy: a randomized clinical trial.

PURPOSE: Despite the uncertain effects of anxiolytic premedication with benzodiazepines on the quality of postoperative recovery, perioperative benzodiazepine administration is still a common practice in many hospitals. We evaluated the effect of premedication with midazolam on the quality of recovery in hospitalized patients undergoing a laparotomy. METHODS: We conducted a single-centre randomized placebo-controlled, double-blinded clinical trial from July 2014 to September 2015. We included 192 patients aged > 18 yr scheduled for elective laparotomy with a planned postoperative stay of ≥ three days. Participants were randomized into two groups to receive either midazolam 3 mg or sodium chloride 0.9% intravenously as premedication prior to surgery. Patients were followed up for up to one week after surgery. The primary outcome was the Quality of Recovery-40 (QoR-40) score on postoperative day (POD) 3. The secondary outcomes included the QoR-40 score on POD 7, and the State-Trait Anxiety Inventory, State-Trait Anger Scale, Multidimensional Fatigue Inventory, and the Hospital Anxiety and Depression Scale scores. RESULTS: The mean (standard deviation) postoperative QoR-40 scores on POD 3 were not significantly different in the midazolam group compared with controls [166.4 (17.0) vs 163.9 (19.8), respectively; mean difference, 2.3; 95% confidence interval, - 2.9 to 8.4; P = 0.35]. There were no between-group differences in any of the secondary outcomes. CONCLUSIONS: Administration of midazolam as premedication for laparotomy patients did not improve the quality of recovery up to one week after surgery. General prescription of midazolam as premedication can be questioned and might only suit some patients. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT01993459); registered 29 October, 2013.

Recovery of cefazolin and clindamycin in in vitro pediatric CPB systems.

Cardiopulmonary bypass (CPB) is often necessary for congenital cardiac surgery, but CPB can alter drug pharmacokinetic parameters resulting in underdosing. Inadequate plasma levels of antibiotics could lead to postoperative infections with increased morbidity. The influence of pediatric CPB systems on cefazolin and clindamycin plasma levels is not known. We have measured plasma levels of cefazolin and clindamycin in in vitro pediatric CPB systems. We have tested three types of CPB systems. All systems were primed and spiked with clindamycin and cefazolin. Samples were taken at different time points to measure the recovery of cefazolin and clindamycin. Linear mixed model analyses were performed to assess if drug recovery was different between the type of CPB system and sampling time point. The experiments were conducted at a tertiary university hospital. 81 samples were analyzed. There was a significant difference in the recovery over time between CPB systems for cefazolin and clindamycin (P < .001). Cefazolin recovery after 180 minutes was 106% (95% CI: 91-123) for neonatal, 99% (95% CI: 85-115) for infant, and 77% (95% CI: 67-89) for pediatric systems. Clindamycin recovery after 180 minutes was 143% (95% CI: 116-177) for neonatal, 111% (95% CI: 89-137) for infant, and 120% (95% CI: 97-149) for pediatric systems. Clindamycin recovery after 180 minutes compared to the theoretical concentration was 0.4% for neonatal, 1.2% for infants, and 0.6% for pediatric systems. The recovery of cefazolin was high in the neonatal and infant CPB systems and moderate in the pediatric system. We found a large discrepancy between the theoretical and measured concentrations of clindamycin in all tested CPB systems.

Small intra-individual variability of the pre-ejection period justifies the use of pulse transit time as approximation of the vascular transit.

BACKGROUND: Vascular transit time (VTT) is the propagation time of a pulse wave through an artery; it is a measure for arterial stiffness. Because reliable non-invasive VTT measurements are difficult, as an alternative we measure pulse transit time (PTT). PTT is defined as the time between the R-wave on electrocardiogram and arrival of the resulting pulse wave in a distal location measured with photoplethysmography (PPG). The time between electrical activation of the ventricles and the resulting pulse wave after opening of the aortic valve is called the pre-ejection period (PEP), a component of PTT. The aim of this study was to estimate the variability of PEP at rest, to establish how accurate PTT is as approximation of VTT. METHODS: PTT was measured and PEP was assessed with echocardiography (gold standard) in three groups of 20 volunteers: 1) a control group without cardiovascular disease aged <50 years and 2) aged >50 years, and 3) a group with cardiovascular risk factors, defined as arterial hypertension, dyslipidemia, kidney failure and diabetes mellitus. RESULTS: Per group, the mean PEP was: 1) 58.5 ± 13.0 ms, 2) 52.4 ± 11.9 ms, and 3) 57.6 ± 11.6 ms. However, per individual the standard deviation was much smaller, i.e. 1) 2.0-5.9 ms, 2) 2.8-5.1 ms, and 3) 1.6-12.0 ms, respectively. There was no significant difference in the mean PEP of the 3 groups (p = 0.236). CONCLUSION: In conclusion, the intra-individual variability of PEP is small. A change in PTT in a person at rest is most probably the result of a change in VTT rather than of PEP. Thus, PTT at rest is an easy, non-invasive and accurate approximation of VTT for monitoring arterial stiffness.

Increase in intracranial pressure by application of a rigid cervical collar: a pilot study in healthy volunteers.

OBJECTIVES: Rigid cervical collars are known to increase intracranial pressure (ICP) in severe traumatic brain injury (TBI). Cerebral blood flow might decrease according to the Kellie Monroe doctrine. For this reason, the use of the collar in patients with severe TBI has been abandoned from several trauma protocols in the Netherlands. There is no evidence on the effect of a rigid collar on ICP in patients with mild or moderate TBI or indeed patients with no TBI. As a first step we tested the effect in healthy volunteers with normal ICPs and intact autoregulation of the brain. METHODS: In this prospective blinded cross-over study, we evaluated the effect of application of a rigid cervical collar in 45 healthy volunteers by measuring their optical nerve sheath diameter (ONSD) by transocular sonography. Sonographic measurement of the ONSD behind the eye is an indirect noninvasive method to estimate ICP and pressure changes. RESULTS: We included 22 male and 23 female volunteers. In total 360 ONSD measurements were performed in these 45 volunteers. Application of a collar resulted in a significant increase in ONSD in both the left (ß=0.06, 95% confidence interval: 0.05-0.07, P<0.001) and the right eye (ß=0.01, 95% confidence interval: 0.00-0.02, P=0.027) CONCLUSION: Application of a rigid cervical collar significantly increases the ONSD in healthy volunteers with intact cerebral autoregulation. This suggests that ICP may increase after application of a collar. In healthy volunteers, this seems to be of minor importance. On the basis of our findings the effect of a collar on ONSD and ICP in patients with mild and moderate TBI needs to be determined.

Risk of abdominal aortic aneurysm (AAA) among male and female relatives of AAA patients.

Sex affects the presentation, treatment, and outcomes of abdominal aortic aneurysm (AAA). Although AAAs are less prevalent in women, at least in the general population, women with an AAA have a poorer prognosis in comparison to men. Sex differences in the genetic predisposition for aneurysm disease remain to be established. In this study we investigated the familial risk of AAA for women compared to men. All living AAA patients included in a 2004-2012 prospective database were invited to the multidisciplinary vascular/genetics outpatient clinic between 2009 and 2012 for assessment of family history using detailed questionnaires. AAA risk for male and female relatives was calculated separately and stratified by sex of the AAA patients. Families of 568 AAA patients were investigated and 22.5% of the patients had at least one affected relative. Female relatives had a 2.8-fold and male relatives had a 1.7-fold higher risk than the estimated sex-specific population risk. Relatives of female AAA patients had a higher aneurysm risk than relatives of male patients (9.0 vs 5.9%, p = 0.022), corresponding to 5.5- and 2.0-fold increases in aneurysm risk in the female and male relatives, respectively. The risk for aortic aneurysm in relatives of AAA patients is higher than expected from population risk. The excess risk is highest for the female relatives of AAA patients and for the relatives of female AAA patients. These findings endorse targeted AAA family screening for female and male relatives of all AAA patients.