Optimal NIV Medicare Access Promotion: Patients With Thoracic Restrictive Disorders: A Technical Expert Panel Report From the American College of Chest Physicians, the American Association for Respiratory Care, the American Academy of Sleep Medicine, and the American Thoracic Society.

The existing coverage criteria for noninvasive ventilation (NIV) do not recognize the benefits of early initiation of NIV for those with thoracic restrictive disorders and do not address the unique needs for daytime support as the patients progress to ventilator dependence. This document summarizes the work of the thoracic restrictive disorder Technical Expert Panel working group. The most pressing current coverage barriers identified were: (1) delays in implementing NIV treatment; (2) lack of coverage for many nonprogressive neuromuscular diseases; and (3) lack of clear policy indications for home mechanical ventilation (HMV) support in thoracic restrictive disorders. To best address these issues, we make the following key recommendations: (1) given the need to encourage early initiation of NIV with bilevel positive airway pressure devices, we recommend that symptoms be considered as a reason to initiate therapy even at mildly reduced FVCs; (2) broaden CO2 measurements to include surrogates such as transcutaneous, end-tidal, or venous blood gas; (3) expand the diagnostic category to include phrenic nerve injuries and disorders of central drive; (4) allow a bilevel positive airway pressure device to be advanced to an HMV when the vital capacity is < 30% or to address severe daytime respiratory symptoms; and (5) provide additional HMV when the patient is ventilator dependent with use > 18 h per day. Adoption of these proposed recommendations would result in the right device, at the right time, for the right type of patients with thoracic restrictive disorders.

Assessment of the SpO2/FiO2 ratio as a tool for hypoxemia screening in the emergency department.

OBJECTIVE: We assessed the performance of the ratio of peripheral arterial oxygen saturation to the inspired fraction of oxygen (SpO2/FiO2) to predict the ratio of partial pressure arterial oxygen to the fraction of inspired oxygen (PaO2/FiO2) among patients admitted to our emergency department (ED) during the SARS-CoV-2 outbreak. METHODS: We retrospectively studied patients admitted to an academic-level ED in France who were undergoing a joint measurement of SpO2 and arterial blood gas. We compared SpO2 with SaO2 and evaluated performance of the SpO2/FiO2 ratio for the prediction of 300 and 400 mmHg PaO2/FiO2 cut-off values in COVID-19 positive and negative subgroups using receiver-operating characteristic (ROC) curves. RESULTS: During the study period from February to April 2020, a total of 430 arterial samples were analyzed and collected from 395 patients. The area under the ROC curves of the SpO2/FiO2 ratio was 0.918 (CI 95% 0.885-0.950) and 0.901 (CI 95% 0.872-0.930) for PaO2/FiO2 thresholds of 300 and 400 mmHg, respectively. The positive predictive value (PPV) of an SpO2/FiO2 threshold of 350 for PaO2/FiO2 inferior to 300 mmHg was 0.88 (CI95% 0.84-0.91), whereas the negative predictive value (NPV) of the SpO2/FiO2 threshold of 470 for PaO2/FiO2 inferior to 400 mmHg was 0.89 (CI95% 0.75-0.96). No significant differences were found between the subgroups. CONCLUSIONS: The SpO2/FiO2 ratio may be a reliable tool for hypoxemia screening among patients admitted to the ED, particularly during the SARS-CoV-2 outbreak.

Transcutaneous Carbon Dioxide Measurement in Adult Patients with Neuromuscular Disorders: A quality Level Assessment.

BACKGROUND: Carbon dioxide tension (PCO2) monitoring during sleep, is crucial to identify respiratory failure in patients with neuromuscular disorders (NMD). Transcutaneous PCO2 monitoring is an available technique to measure PCO2. OBJECTIVES: To assess the quality level of transcutaneous blood gas measurements via SenTec monitor. METHODS: A 12-month analysis of SenTec measurements was conducted in a Belgian Centre for Home Mechanical Ventilation (HMV). Over two consecutive nights; SpO2 and PCO2 measurements, the presence of PCO2 drift and drift correction with SenTec, were reviewed and scores (0, 1, 2 for poor, medium and high level) were assigned to estimate the quality of measurements. RESULTS: Sixty-nine NMD patients met the inclusion criteria, of which 48/69 used HMV. PCO2 drift and drift correction were present in 15% and 68% of the 138 recordings, respectively. The quality level of measurements throughout night 1, scored 1.55 (0-2). The relevance of our clinical findings from SenTec scoring 1.94 (1-2); was considered highly satisfactory. HMV was ineffective in 24/48 patients. Among 12 patients with hypercapnia, 8 patients improved PCO2 between night 1 and 2. Among 12 patients with hypocapnia, PCO2 improved in 4/12 patients, who reached the range of normal PCO2 (35-47 mmHg). CONCLUSIONS: The quality of SenTec measurements was acceptable in the majority of recordings and clinical findings were deemed satisfactory in all cases. A single SenTec measurement was sufficient to determine the need for NIV. However, two SenTec registrations were insufficient to both improve NIV effectiveness in 50% of cases, and, to ensure follow-up of our interventions.

A Randomized Trial of Initiation of Chronic Noninvasive Mechanical Ventilation at Home vs In-Hospital in Patients With Neuromuscular Disease and Thoracic Cage Disorder: The Dutch Homerun Trial.

BACKGROUND: There is an increasing demand for home mechanical ventilation (HMV) in patients with chronic respiratory insufficiency. At present, noninvasive ventilation is exclusively initiated in a clinical setting at all four centers for HMV in the Netherlands. In addition to its high societal costs and patient discomfort, commencing HMV is often delayed because of a lack of hospital bed capacity. RESEARCH QUESTION: Is HMV initiation at home, using a telemonitoring approach, noninferior to in-hospital initiation in a nationwide study? STUDY DESIGN AND METHODS: We conducted a nationwide, randomized controlled noninferiority trial, in which every HMV center recruited 24 patients (home [n = 12] vs hospital [n = 12]) with a neuromuscular disease or thoracic cage disorder, all with an indication to start HMV. Change in arterial CO2 (Paco2) over a 6-month period was considered the primary outcome, and quality of life and costs were assessed as secondary outcomes. RESULTS: A total of 96 patients were randomized, most of them diagnosed with neuromuscular disease. We found a significant improvement in Paco2 within both groups (home: from 6.1 to 5.6 kPa [P < .01]; hospital: from 6.3 to 5.6 kPa [P < .01]), with no significant differences between groups. Health-related quality of life showed significant improvement on various subscales; however, no significant differences were observed between the home and hospital groups. From a societal perspective, a cost reduction of more than €3,200 ($3,793) per patient was evident in the home group. INTERPRETATION: This nationwide, multicenter study shows that HMV initiation at home is noninferior to hospital initiation, as it shows the same improvement in gas exchange and health-related quality of life. In fact, from a patient's perspective, it might even be a more attractive approach. In addition, starting at home saves over €3,200 ($3,793) per patient over a 6-month period. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT03203577; URL: www.clinicaltrials.gov.

OUTPATIENT ANALYTIC ASSESSMENT OF ANOREXIA NERVOSA - THE IMPORTANCE OF VENOUS BLOOD GASES.

OBJECTIVE: To evaluate serum biochemical parameters' evolution, especially venous blood gas (VBG), in anorexia nervosa (AN), correlating with clinical parameters. METHODS: Retrospective study including out-patient AN adolescents, between January 2014 and May 2017. Three evaluations were compared: t1) first consultation; t2) consultation with the lowest body mass index (BMI) z-score and t3) with the highest BMI z-score. RESULTS: A total of 24 adolescents (87.5% females) were included, mean age of presentation of 14.9±1.7 years, onset of symptoms 6.4±3.2 months before the first visit. In t1, BMI z-score of -1.91±1.11 kg/m2 and ideal weight % of 84.3±9.2. Amenorrhea was present in 88%. In t2 the analytical alterations were: altered VBG in 100%, altered ferritin (72% elevated), altered thyroid function (53% with thyroxine decrease), dyslipidemia (31% elevation of high density lipoprotein, 25% hypercholesterolemia), elevation of urea (25%), elevation of alanine aminotransferase (14%), hypoglycemia (14%), anemia (9%). Respiratory acidosis was present in 91% in t1, 100% in t2 and 94% in t3. There was a significant decrease between t2 and t3 in mean pCO2 (57.2 versus 53.6 mmHg; p=0.009) and mean HCO3 (30.0 versus 28.8 mEq/L; p=0.023). CONCLUSIONS: Respiratory acidosis and increased ferritin were common in this group. Respiratory acidosis was the most frequent abnormality with significant pCO2 and HCO3 variation in the recovery phase. VBG should be considered in AN evaluation, once it seems to be important in assessing the severity of the disease and its subsequent follow-up.

Outpatient analytic assessment of anorexia nervosa — the importance of venous blood gases / Avaliação laboratorial em ambulatório na anorexia nervosa: a importância da gasometria venosa

ABSTRACT Objective: To evaluate serum biochemical parameters' evolution, especially venous blood gas (VBG), in anorexia nervosa (AN), correlating with clinical parameters. Methods: Retrospective study including out-patient AN adolescents, between January 2014 and May 2017. Three evaluations were compared: t1) first consultation; t2) consultation with the lowest body mass index (BMI) z-score and t3) with the highest BMI z-score. Results: A total of 24 adolescents (87.5% females) were included, mean age of presentation of 14.9±1.7 years, onset of symptoms 6.4±3.2 months before the first visit. In t1, BMI z-score of -1.91±1.11 kg/m2 and ideal weight % of 84.3±9.2. Amenorrhea was present in 88%. In t2 the analytical alterations were: altered VBG in 100%, altered ferritin (72% elevated), altered thyroid function (53% with thyroxine decrease), dyslipidemia (31% elevation of high density lipoprotein, 25% hypercholesterolemia), elevation of urea (25%), elevation of alanine aminotransferase (14%), hypoglycemia (14%), anemia (9%). Respiratory acidosis was present in 91% in t1, 100% in t2 and 94% in t3. There was a significant decrease between t2 and t3 in mean pCO2 (57.2 versus 53.6 mmHg; p=0.009) and mean HCO3 (30.0 versus 28.8 mEq/L; p=0.023). Conclusions: Respiratory acidosis and increased ferritin were common in this group. Respiratory acidosis was the most frequent abnormality with significant pCO2 and HCO3 variation in the recovery phase. VBG should be considered in AN evaluation, once it seems to be important in assessing the severity of the disease and its subsequent follow-up.

RESUMO Objetivo: Avaliar a evolução laboratorial, particularmente da gasometria venosa, na anorexia nervosa (AN), correlacionando os achados com parâmetros clínicos. Métodos: Estudo retrospetivo com adolescentes com AN seguidos em ambulatório, entre janeiro de 2014 e maio de 2017. Foram comparadas três avaliações: (t1) primeira consulta; (t2) consulta com escore Z de índice de massa corpórea (IMC) mais baixo; e (t3) consulta com escore Z de IMC mais elevado. Resultados: Incluídos 24 adolescentes, 87,5% do sexo feminino, idade média de apresentação de 14,9±1,7 anos, início dos sintomas 6,4±3,2 meses antes da primeira consulta. Em t1, escore Z de IMC de -1,91±1,11 kg/m2 e % de peso ideal de 84,3±9,2. Tinham amenorreia 88%. Em t2 as alterações laboratoriais encontradas foram: gasometria venosa alterada em 100%, ferritina alterada (72% elevada), função tiroideia alterada (53% com diminuição da tiroxina), dislipidemia (31% com elevação de lipoproteína de alta densidade, 25% com hipercolesterolemia), elevação da ureia (25%), elevação da alanina aminotransferase (14%), hipoglicemia (14%) e anemia (9%). A acidose respiratória esteve presente em 91% em t1, 100% em t2 e 94% em t3. Verificou-se diminuição significativa entre t2 e t3 da pressão parcial de CO2 (pCO2) média (57,2 versus 53,6 mmHg; p=0,009) e HCO3 médio (30,0 versus 28,8 mEq/L; p=0,023). Conclusões: A acidose respiratória e o aumento da ferritina foram comuns nesse grupo. Acidose respiratória foi a alteração mais frequente, com variação significativa de pCO2 e HCO3 na fase de recuperação. A gasometria venosa deve ser considerada na avaliação laboratorial na AN, pois parece ser importante na avaliação da gravidade e monitorização da doença.

Performance of the COPD Assessment Test in patients with connective tissue disease-associated interstitial lung disease.

BACKGROUND: Patients with connective tissue disease-associated interstitial lung disease (CTD-ILD) often experience impaired health status. In daily clinical practice, a short and easy instrument for assessing health status would be useful to help better understand the patient's condition. The COPD Assessment Test (CAT) is a simple questionnaire about respiratory symptoms and their impact. We aimed to examine the CAT's performance characteristics and to generate data to support its reliability and validity in patients with CTD-ILD. METHODS: We used data from 132 CTD-ILD patients evaluated at Tosei General Hospital from July 2011 to July 2016 to assess the cross-sectional and longitudinal validity of the CAT. RESULTS: The mean age of the patients was 64.5 years and 87 (66%) were women. There were no significant differences in CAT score between any of the CTD subgroups. Internal consistency (Cronbach's α = 0.881) and repeatability (intraclass correlation coefficient [ICC] = 0.803) for the CAT score were acceptable. At baseline, CAT score was significantly associated with clinically meaningful measures of physiologic function, exercise capacity, and dyspnea. Change in CAT score over 6-12 months was also associated with change in other measures. In the distribution- and anchor-based analyses, the estimated minimal clinically important difference of CAT score was 1-4 points. CONCLUSION: These data support the validity and reliability of CAT as a sensitive measure for assessing health status in patients with CTD-ILD.

Acid-base assessment of post-parturient German Holstein dairy cows from jugular venous blood and urine: A comparison of the strong ion approach and traditional blood gas analysis.

Evaluating acid-base status is important for monitoring dairy herd health. In a field study, we aimed to compare the acid-base status measured by net acid-base excretion (NABE) in urine with results of venous blood analysis in clinically healthy, but possibly metabolically burdened cows in their transition period. For this, we sampled blood from the jugular vein and urine from 145 German Holstein cows within 1 to 76 days post-partum. In blood, the metabolic parameters non-esterified fatty acids (NEFA) and ß-hydroxybutyrate (BHB), as well as numerous parameters of the acid-base status were measured. The traditional approach, based on bicarbonate concentration, base excess (BE) and anion gap (AG), was compared to the strong ion approach variables, e.g. acid total (Atot), measured strong ion difference (SIDm), strong ion gap (SIG), and unmeasured anions (XA), respectively. Results of both approaches were set against the outcome of urine analysis, i.e. the NABE, base-acid ratio and pH of urine, in a cluster analysis, which provided 7 moderately stable clusters. Evaluating and interpreting these 7 clusters offered novel insights into the pathophysiology of the acid-base equilibrium in fresh post-partum dairy cows. Especially in case of subclinical acid-base disorders, the parameters of the strong ion difference theory, particularly SIDm, Atot and SIG or XA, provided more in-depth information about acid-base status than the traditional parameters BE, bicarbonate or AG in blood. The acid-base status of fresh cows with protein aberrations in blood could be differentiated in a much better way using the strong ion approach than by traditional blood gas analysis or by the measurement of urinary excretion. Therefore, the strong ion approach seems to be a suitable supplement for monitoring acid-base balance in dairy cattle.

Reliability of forearm oxygen uptake during handgrip exercise: assessment by ultrasonography and venous blood gas.

Assessment of forearm oxygen uptake (V˙O2 ) during handgrip exercise is a keenly investigated concept for observing small muscle mass metabolism. Although a combination of Doppler ultrasound measurements of brachial artery blood flow (Q˙) and blood gas drawn from a deep forearm vein has been utilized to calculate forearm V˙O2 for more than two decades, the applicability of this experimental design may benefit from a thorough evaluation of its reliability during graded exercise. Therefore, we evaluated the reliability of this technique during incremental handgrip exercise in ten healthy young (24 ± 3(SD) years.) males. V˙O2 and work rate (WR) exhibited a linear relationship (1.0 W: 43.8 ± 10.1 mL·min-1 ; 1.5 W: 53.8 ± 14.1 mL·min-1 ; 2.0 W: 63.4 ± 16.3 mL·min-1 ; 2.5 W: 72.2 ± 17.6 mL·min-1 ; 3.0 W: 79.2 ± 18.6 mL·min-1 ; r = 0.65, P < 0.01). In turn, V˙O2 was strongly associated with Q˙ (1.0 W: 359 ± 86 mL·min-1 ; 1.5 W: 431 ± 112 mL·min-1 ; 2.0 W: 490 ± 123 mL·min-1 ; 2.5 W: 556 ± 112 mL·min-1 ; 3.0 W: 622 ± 131 mL·min-1 ; r = 0.96; P < 0.01), whereas arteriovenous oxygen difference (a-vO2diff ) remained constant following all WRs (123 ± 11-130 ± 10 mL·L-1 ). Average V˙O2 test-retest difference was -0.4 mL·min-1 with ±2SD limits of agreement (LOA) of 8.4 and -9.2 mL·min-1 , respectively, whereas coefficients of variation (CVs) ranged from 4-7%. Accordingly, test-retest Q˙ difference was 11.9 mL·min-1 (LOA: 84.1 mL·min-1 ; -60.4 mL·min-1 ) with CVs between 4 and 7%. Test-retest difference for a-vO2diff was -0.28 mL·dL-1 (LOA: 1.26mL·dL-1 ; -1.82 mL·dL-1 ) with 3-5% CVs. In conclusion, our results revealed that forearm V˙O2 determination by Doppler ultrasound and direct venous sampling is linearly related to WR, and a reliable experimental design across a range of exercise intensities.

Evaluation of Miniature Dynamic Light Scattering Technology for the Assessment of Hemodynamic Status During Graded Hemorrhage and Retransfusion in Pigs.

BACKGROUND: Hemorrhagic shock with occult hypoperfusion is a key challenge to prehospital staff during triage and transfer of patients, especially during mass casualty incidents. Recent advances in Dynamic Light Scattering (DLS), and miniaturization of this technology, has resulted in noninvasive sensors capable of continuously monitoring tissue perfusion. This study evaluated the ability of miniature DLS (mDLS) sensors to assess hemodynamic status in a porcine model of hemorrhage. METHODS: Following ethics committee approval, anesthetized and ventilated pigs underwent graded hemorrhage and then retransfusion. Standard vital signs were monitored in conjunction with a thermodilution cardiac output (CO), central venous pressure (CVP), and arterial blood gases. The mDLS sensor was attached to each animal's leg and all monitoring measurements were taken 5 minutes after completion of each period of hemorrhage and retransfusion to allow equilibration. RESULTS: All measured parameters changed during bleeding and retransfusion. During bleeding; p value were 0.011 for heart rate, 0.07 for CVP, <0.001 for both mean arterial pressure, and mDLS. During retransfusion; p values were 0.023 for heart rate, 0.008 for CVP, and <0.001 for both mean arterial pressure and mDLS. Pearson correlation between changes in mDLS and CO demonstrated r value of 0.917 during hemorrhage and 0.965 during retransfusion. Changes in hemoglobin were not statistically significant during bleeding (p = 0.331) but were during retransfusion (p = 0.0001). Changes of bicarbonate, base excess, and lactate were found to be statistically significant during both phases of the experiment (p = 0.001). CONCLUSIONS: In an animal model of hemorrhagic shock, the mDLS sensor strongly correlates with traditional measures of CO. This initial assessment supports further investigation of this technology in human studies.

Assessment of changes in lactate concentration with intravascular microdialysis during high-risk cardiac surgery using the trend interchangeability method.

Background: Blood lactate is a strong predictor of mortality, and repeated blood lactate assays are recommended during surgery in high-risk patients. We hypothesized that the use of intravascular microdialysis incorporated in a central venous catheter would be interchangeable with the reference blood gas technique to monitor changes in blood lactate. Methods: Microdialysis and central venous blood lactate measurements were recorded simultaneously in high-risk cardiac surgical patients. The correlation between absolute values was determined by linear regression, and the Bland-Altman test for repeated measurements was used to compare bias, precision, and limits of agreement. Changes in lactate measurements were evaluated with a four-quadrant plot and trend interchangeability method (TIM). Results: In the 23 patients analysed, the central venous catheter was used as part of standard care, with no complications. The correlation coefficient for absolute values ( n =104) was 0.96 ( P <0.0001). The bias, precision, and limits of agreement were -0.19, 0.51, and -1.20 to 0.82 mmol litre -1 , respectively. The concordance rate for changes in blood lactate measurements ( n =80) was 94% with the four-quadrant plot. In contrast, the TIM showed that 23 (29) changes in lactate measurements were not interpretable, and among the remaining 57 (71) interpretable changes, 18 (32) were interchangeable, 8 (14) were in the grey zone, and 31 (54) were not interchangeable. Conclusions: Microdialysis with a central venous catheter appears to provide reliable absolute blood lactate values. Although changes in blood lactate measurements showed an excellent concordance rate, changes between the two methods were poorly interchangeable with the TIM. Clinical trial registration: NCT02296593.

Ultrasonic monitoring in the assessment of pulmonary recruitment and the best positive end-expiratory pressure.

The aim of this study was to explore the clinical value of ultrasonic monitoring in the assessment of pulmonary recruitment and the best positive end-expiratory pressure (PEEP).Between January 2015 and June 2017, 40 patients with acute respiratory distress syndrome in our hospital were randomly divided into 2 groups: ultrasound group (ULS group; n = 20) and oxygenation group (OXY group; n = 20). The PEEP incremental method was used to perform recruitment maneuvers. Ultrasound scoring and the oxygenation method were used to evaluate the pulmonary recruitment endpoint. The best PEEP was chosen by ultrasound scoring and the oxygenation method after achieving the pulmonary recruitment endpoint and sustaining it for 15 minutes.The oxygenation index, PEEP, peak airway pressure (Ppeak), mean airway pressure (Pmean), and dynamic compliance (Cdyn) in the OXY group were significantly lower than those in the ULS group (P < .05) at the pulmonary recruitment endpoint; however, there was no statistical significance in the mean arterial blood pressure (MAP) or heart rate (HR) (P > .05). The best PEEPs in the OXY and ULS groups were 13.1 ±â€Š3.1 and 15.7 ±â€Š4.2 cmH2O, respectively, with a significant difference between the 2 groups (t = 2.227, P = .016). Compared with the basal state, the Cdyn, oxygenation index, Pmean, and Ppeak in both groups significantly increased after pulmonary recruitment (P < .05). Furthermore, the Cdyn and oxygenation index in the ULS group were significantly higher than those in the OXY group after pulmonary recruitment (P < .05). The HR in both groups significantly increased, and the MAP significantly decreased. Two hours after recruitment, the HR and MAP returned to near basal levels without a significant difference between the 2 groups (P > .05).Lung ultrasound can be used to detect the endpoint of lung recruitment and the best PEEP, with good effects on lung compliance and oxygenation improvement.

Brain oxygen saturation assessment in neonates using T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy.

Although near-infrared spectroscopy is increasingly being used to monitor cerebral oxygenation in neonates, it has a limited penetration depth. The T2-prepared Blood Imaging of Oxygen Saturation (T2-BIOS) magnetic resonance sequence provides an oxygen saturation estimate on a voxel-by-voxel basis, without needing a respiratory calibration experiment. In 15 neonates, oxygen saturation measured by T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy were compared. In addition, these measures were compared to cerebral blood flow and venous oxygen saturation in the sagittal sinus. A strong linear relation was found between the oxygen saturation measured by magnetic resonance imaging and the oxygen saturation measured by near-infrared spectroscopy ( R2 = 0.64, p < 0.001). Strong linear correlations were found between near-infrared spectroscopy oxygen saturation, and magnetic resonance imaging measures of frontal cerebral blood flow, whole brain cerebral blood flow and venous oxygen saturation in the sagittal sinus ( R2 = 0.71, 0.50, 0.65; p < 0.01). The oxygen saturation obtained by T2-prepared blood imaging of oxygen saturation correlated with venous oxygen saturation in the sagittal sinus ( R2 = 0.49, p = 0.023), but no significant correlations could be demonstrated with frontal and whole brain cerebral blood flow. These results suggest that measuring oxygen saturation by T2-prepared blood imaging of oxygen saturation is feasible, even in neonates. Strong correlations between the various methods work as a cross validation for near-infrared spectroscopy and T2-prepared blood imaging of oxygen saturation, confirming the validity of using of these techniques for determining cerebral oxygenation.

Transcutaneous PTCCO2 measurement in combination with arterial blood gas analysis provides superior accuracy and reliability in ICU patients.

Hyper or hypoventilation may have serious clinical consequences in critically ill patients and should be generally avoided, especially in neurosurgical patients. Therefore, monitoring of carbon dioxide partial pressure by intermittent arterial blood gas analysis (PaCO2) has become standard in intensive care units (ICUs). However, several additional methods are available to determine PCO2 including end-tidal (PETCO2) and transcutaneous (PTCCO2) measurements. The aim of this study was to compare the accuracy and reliability of different methods to determine PCO2 in mechanically ventilated patients on ICU. After approval of the local ethics committee PCO2 was determined in n = 32 ICU consecutive patients requiring mechanical ventilation: (1) arterial PaCO2 blood gas analysis with Radiometer ABL 625 (ABL; gold standard), (2) arterial PaCO2 analysis with Immediate Response Mobile Analyzer (IRMA), (3) end-tidal PETCO2 by a Propaq 106 EL monitor and (4) transcutaneous PTCCO2 determination by a Tina TCM4. Bland-Altman method was used for statistical analysis; p < 0.05 was considered statistically significant. Statistical analysis revealed good correlation between PaCO2 by IRMA and ABL (R2 = 0.766; p < 0.01) as well as between PTCCO2 and ABL (R2 = 0.619; p < 0.01), whereas correlation between PETCO2 and ABL was weaker (R2 = 0.405; p < 0.01). Bland-Altman analysis revealed a bias and precision of 2.0 ± 3.7 mmHg for the IRMA, 2.2 ± 5.7 mmHg for transcutaneous, and -5.5 ± 5.6 mmHg for end-tidal measurement. Arterial CO2 partial pressure by IRMA (PaCO2) and PTCCO2 provided greater accuracy compared to the reference measurement (ABL) than the end-tidal CO2 measurements in critically ill in mechanically ventilated patients patients.

Pain assessment during blood collection from sedated and mechanically ventilated children.

OBJECTIVE: This study assessed pain and observed physiological parameters in sedated and mechanically ventilated children during a routine procedure. METHODS: This observational study was performed in a pediatric intensive care unit. Thirty-five children between 1 month and 12 years of age were assessed before, during, and five minutes after an arterial blood collection for gas analysis (painful procedure). Face, Legs, Activity, Cry and Consolability scale was used to assess pain. In addition, patients' heart rate, respiratory rate, peripheral saturation of oxygen and blood pressure (diastolic and systolic) were recorded. COMFORT-B scale was applied before the pain and physiological parameter assessments to verify sedation level of the subjects. RESULTS: There was an increase in Face, Legs, Activity, Cry and Consolability score (p = 0.0001) during painful stimuli. There was an increase in heart rate (p = 0.03), respiratory rate (p = 0.001) and diastolic blood pressure (p = 0.006) due to pain caused by the routine procedure. CONCLUSIONS: This study suggests that assessments of pain using standard scales, such as Face, Legs, Activity, Cry and Consolability score, and other physiological parameters should be consistently executed to optimize pain management in pediatric intensive care units.

Avaliação da dor durante coleta de sangue em crianças sedadas e submetidas à ventilação mecânica / Pain assessment during blood collection from sedated and mechanically ventilated children

RESUMO Objetivo: Avaliar a dor e observar parâmetros fisiológicos em crianças sedadas e submetidas à ventilação mecânica durante um procedimento de rotina. Métodos: Estudo observacional realizado em uma unidade de terapia intensiva pediátrica. Foram avaliadas 35 crianças, com idades entre 1 mês e 12 anos, em três momentos distintos: antes, durante e 5 minutos após coleta de sangue arterial para análise gasométrica (procedimento doloroso). Utilizou-se a Escala Face, Legs, Activity, Cry and Consolability para avaliação da dor e foram registradas a frequência cardíaca, frequência respiratória, saturação periférica de oxigênio e pressão arterial (sistólica e diastólica). O nível de sedação dos participantes foi verificado utilizando-se a escala Comfort-B, aplicada antes da mensuração da dor e da avaliação dos parâmetros fisiológicos. Resultados: Durante os estímulos dolorosos, ocorreu aumento do escore da Escala Face, Legs, Activity, Cry and Consolability (p = 0,0001). Houve também aumento da frequência cardíaca (p = 0,03), da frequência respiratória (p = 0,001) e da pressão arterial diastólica (p = 0,006) em razão da dor causada pelo procedimento de rotina. Conclusões: Avaliação da dor com uso de escalas padrão, como a Escala Face, Legs, Activity, Cry and Consolability, e observação de parâmetros fisiológicos, deve ser realizada rotineiramente para melhorar o manejo da dor nas unidades de terapia intensiva pediátricas.

ABSTRACT Objective: This study assessed pain and observed physiological parameters in sedated and mechanically ventilated children during a routine procedure. Methods: This observational study was performed in a pediatric intensive care unit. Thirty-five children between 1 month and 12 years of age were assessed before, during, and five minutes after an arterial blood collection for gas analysis (painful procedure). Face, Legs, Activity, Cry and Consolability scale was used to assess pain. In addition, patients' heart rate, respiratory rate, peripheral saturation of oxygen and blood pressure (diastolic and systolic) were recorded. COMFORT-B scale was applied before the pain and physiological parameter assessments to verify sedation level of the subjects. Results: There was an increase in Face, Legs, Activity, Cry and Consolability score (p = 0.0001) during painful stimuli. There was an increase in heart rate (p = 0.03), respiratory rate (p = 0.001) and diastolic blood pressure (p = 0.006) due to pain caused by the routine procedure. Conclusions: This study suggests that assessments of pain using standard scales, such as Face, Legs, Activity, Cry and Consolability score, and other physiological parameters should be consistently executed to optimize pain management in pediatric intensive care units.

The usefulness of cardiopulmonary exercise testing in assessment of patients with suspected coronary artery disease.

OBJECTIVE: The aim of this study is to assess different parameters of cardiopulmonary exercise testing that can predict the development of myocardial ischaemia in patients with suspected coronary artery disease (CAD) and to identify the parameters which have more correlation with myocardial ischaemia. STUDY DESIGN: Cross-sectional study. METHODS: In this study, a total of 31 men (mean age 57.23±11.09 years) with suggestive symptoms of CAD underwent an exercise stress test with breath-by-breath gas exchange analysis, followed by coronary angiography as the gold standard for diagnosing CAD. RESULTS: The ventilation versus CO2 output (VE/VCO2) peak was significantly different between patients with negative and positive angiography results. Receiver operator characteristic analysis showed an area under the curve of 0.73 for VE/VCO2 peak with diagnostic threshold equal to 35 (95% CI 0.54 to 0.9; p=0.05). Exercise stress testing had sensitivity and specificity of 75% and 40%, respectively. CONCLUSIONS: A change in ventilatory efficiency assessed using the VE/VCO2 peak has the predictive ability to identify exercise-induced myocardial ischaemia. The present study has provided additional evidence of the potential clinical value of cardiopulmonary exercise testing in the diagnosis of CAD.

Robustness of arterial blood gas analysis for assessment of respiratory safety pharmacology in rats.

Whole body plethysmography using unrestrained animals is a common technique for assessing the respiratory risk of new drugs in safety pharmacology studies in rats. However, wide variations in experimental technique make cross laboratory comparison of data difficult and raise concerns that non-appropriate conditions may mask the deleterious effects of test compounds - in particular with suspected respiratory depressants. Therefore, the objective of this study was to evaluate the robustness of arterial blood gas analysis as an alternative to plethysmography in rats. We sought to do this by assessing the effect of different vehicles and times post-surgical catheterization on blood gas measurements, in addition to determining sensitivity to multiple opioids. Furthermore, we determined intra-lab variability from multiple datasets utilizing morphine and generated within a single lab and lastly, inter-lab variability was measured by comparing datasets generated in two separate labs. Overall, our data show that arterial blood gas analysis is a measure that is both flexible in terms of experimental conditions and highly sensitive to respiratory depressants, two key limitations when using plethysmography. As such, our data strongly advocate the adoption of arterial blood gas analysis as an investigative approach to reliably examine the respiratory depressant effects of opioids.

Using venous blood gas analysis in the assessment of COPD exacerbations: a prospective cohort study.

INTRODUCTION: Identifying acute hypercapnic respiratory failure is crucial in the initial management of acute exacerbations of COPD. Guidelines recommend obtaining arterial blood samples but these are more difficult to obtain than venous. We assessed whether blood gas values derived from venous blood could replace arterial at initial assessment. METHODS: Patients requiring hospital treatment for an exacerbation of COPD had paired arterial and venous samples taken. Bland-Altman analyses were performed to assess agreement between arterial and venous pH, CO2 and HCO3-. The relationship between SpO2 and SaO2 was assessed. The number of attempts and pain scores for each sample were measured. RESULTS: 234 patients were studied. There was good agreement between arterial and venous measures of pH and HC)3- (mean difference 0.03 and -0.04, limits of agreement -0.05 to 0.11 and -2.90 to 2.82, respectively), and between SaO2 and SpO2 (in patients with an SpO2 of >80%). Arterial sampling required more attempts and was more painful than venous (mean pain score 4 (IQR 2-5) and 1 (IQR 0-2), respectively, p<0.001). CONCLUSIONS: Arterial sampling is more difficult and more painful than venous sampling. There is good agreement between pH and HCO3- values derived from venous and arterial blood, and between pulse oximetry and arterial blood gas oxygen saturations. These agreements could allow the initial assessment of COPD exacerbations to be based on venous blood gas analysis and pulse oximetry, simplifying the care pathway and improving the patient experience.