Detection of episodic nocturnal hypercapnia in patients with neurodegenerative disorders.

PURPOSE: Episodic nocturnal hypercapnia (eNH) in transcutaneous carbon dioxide pressure (PtcCO2) corresponding to rapid eye movement sleep hypoventilation is a useful biomarker for detecting nocturnal hypoventilation. However, the relationship between eNH and neurodegenerative diseases with sleep-related breathing disorders (SRBDs) is unknown. The aim of this study was to evaluate the relationship between eNH and nocturnal hypoventilation in neurodegenerative diseases. METHODS: Patients with neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), multiple system atrophy (MSA), Parkinson's disease, progressive supranuclear palsy, corticobasal syndrome, and idiopathic normal pressure hydrocephalus, were enrolled and received overnight PtcCO2 monitoring. The patients were divided into groups for eNH and sleep-associated hypoventilation (SH) prevalence analysis: A (ALS), B (MSA), and C (others). RESULTS: Among 110 patients, twenty-three (21%) and 10 (9%) of the patients met eNH and SH criteria, respectively. eNH and SH were significantly more frequent in groups A and B than in C. The prevalence of SH in the patients with eNH was 39% whereas most of patients with SH (90%) presented with eNH. Among patients with daytime carbon dioxide pressure in arterial blood ≤ 45 mmHg, eNH frequency was 13%, whereas none of the patients met SH criteria. The frequency of noninvasive positive pressure ventilation after PtcCO2 monitoring was significantly higher in those with than without eNH. CONCLUSIONS: eNH is common in patients with MSA and ALS who present with SRBD. eNH with overnight PtcCO2 monitoring is a useful biomarker to detect hypoventilation among neurodegenerative diseases with different SRBD mechanisms.

Causes of hypercapnic respiratory failure and associated in-hospital mortality.

BACKGROUND AND OBJECTIVE: Hypercapnic respiratory failure (HRF) can occur due to severe respiratory disease but also because of multiple coexistent causes. There are few data on the prevalence of antecedent causes for HRF and the effect of these causes on prognosis, especially where study inclusion has not been biased with respect to primary diagnosis, interventions received or clinical outcome. We sought to determine the prevalence of pre-specified conditions among patients with HRF and to determine the effect of these causes on in-hospital mortality. METHODS: Cross-sectional study of patients with HRF from 2013 to 2017. Inclusion criteria were PaCO2  >45 mm Hg and pH ≤7.45. Causes of interest were identified using diagnosis codes from hospital records. We used directed acyclic graphs to inform logistic regression models for the outcome of in-hospital death. RESULTS: We identified 873 persons with HRF in the study period. Mean (SD) age was 69 years and 50.4% were males. Acidosis (pH <7.35) was present in 488 (55%) cases. Most (83%) had one or more of the following: obstructive lung disease, lower respiratory tract infection, congestive cardiac failure, sleep disordered breathing, neuromuscular disease, opioid or benzodiazepine use. In-hospital mortality was 12.8%. Obstructive lung disease and cardiac failure were associated with a lower risk of death, whereas respiratory tract infection and neuromuscular disease were associated with increased risk of death. CONCLUSION: HRF is associated with a range of potentially causative conditions, which significantly impact hospital survival. Systematic evaluation of patients with HRF may increase detection of treatable comorbidities.

Relationship Between Episodic Nocturnal Hypercapnia and History of Exacerbations in Patients with Advanced Chronic Obstructive Pulmonary Disease.

Purpose: An episodic increase in transcutaneous carbon dioxide pressure (PtcCO2) is often recognized in patients with advanced chronic obstructive pulmonary disease (COPD) by overnight PtcCO2 monitoring. This phenomenon, called episodic nocturnal hypercapnia (eNH), mainly corresponds to rapid eye movement (REM) sleep-related hypoventilation. However, it is unclear whether eNH is associated with the frequency of COPD exacerbation. We aimed to investigate whether a relationship exists between COPD exacerbation and eNH. Patients and Methods: We enrolled consecutive patients with stable, severe, or very severe COPD with a daytime arterial carbon dioxide pressure (PaCO2) <55.0 mmHg who underwent overnight PtcCO2 monitoring from April 2013 to January 2017. We retrospectively analyzed the prevalence of eNH and sleep-associated hypoventilation (SH) as defined by the American Academy of Sleep Medicine. Moreover, we compared the relationship between the frequency of COPD exacerbations in the previous year and eNH or SH. Results: Twenty-four patients were included in this study. The study patients had a mean daytime PaCO2 and nocturnal PtcCO2 of 43.3 ± 6.8 mmHg and 42.9 ± 9.6 mmHg, respectively. Six (25.0%) and 11 (45.9%) of the 24 patients met the SH and eNH criteria, respectively. The odds ratios of SH and eNH for at least one annual exacerbation were 1.0 [95% confidence interval (CI): 0.16-6.00] and 11.1 [95% CI: 1.39-87.7], respectively. The odds ratios of SH and eNH for at least two annual exacerbations were 0.3 [95% CI: 0.04-2.64] and 6.6 [95% CI: 1.06-39.4], respectively. Conclusion: In patients with advanced COPD and a daytime PaCO2 <55.0 mmHg, eNH may be associated with a history of more frequent exacerbations than SH. Further studies are required to validate these findings.

Comparison of the efficacy and safety of sedation protocols with the use of dexmedetomidine-remifentanil and propofol-remifentanil during percutaneous closure of atrial septal defects: a randomized clinical trial.

BACKGROUND: The study was aimed to compare the efficacy and safety of different sedation protocols of dexmedetomidine-remifentanil and propofol-remifentanil for percutaneous closure of atrial septal defects (ASD) under transthoracic echocardiography (TTE) guidance. MATERIAL AND METHODS: From March 2020 to January 2021, of 114 patients screened, 59 ASD patients scheduled for percutaneous closure under TTE guidance were randomly allocated into the dexmedetomidine-remifentanil (D-R) group (n = 29) and the propofol-remifentanil (P-R) group (n = 30). The incidence of hemodynamic and respiratory adverse events, arterial blood gas analysis, induction and recovery time, pain score, infusion rate of remifentanil, satisfaction of the surgeon and patient, additional sedatives were collected for analysis and comparison. RESULTS: The induction time was longer in the D-R group than that in the P-R group (17.66 ± 2.65 min vs 11.43 ± 1.48 min; difference, 6.22 min; 95% CI 5.10 to 7.35; P < 0.001). No differences were observed in the 2 groups in terms of the additional sedatives, infusion rate of remifentanil, pain score, recovery time (P > 0.05). There was no difference between the two groups regarding the incidence of cardiovascular adverse events (6 [20.7%] vs 4 [13.3%]; difference, 7.4%; 95% CI - 11.7 to 26.5%; P = 0.506). Respiratory adverse events occurred in 1 patient (3.4%) in the D-R group, and 8 patients (26.7%) in the P-R group (difference, 23.3%; 95% CI 6.2 to 40.5%; P = 0.026). The incidence of hypercapnia was significantly lower in the D-R group (4 [13.8%]) than in the P-R group (13 [43.3%]; difference, 29.5%; 95% CI 7.8 to 51.2%; P = 0.012). CONCLUSIONS: Except for more rapid the induction time and higher the surgeon satisfaction score in the propofol-remifentanil protocol, the efficacy was similar between two sedation protocols. The hemodynamic stability was comparable, the dexmedetomidine-remifentanil protocol had superior airway security due to fewer hypercapnia and respiratory adverse events.

Determination of oxygen saturation compared to a prescribed target range using continuous pulse oximetry in acutely unwell medical patients.

BACKGROUND: Both inadequate and excessive administration of oxygen to acutely unwell patients results in risk of harm. Guidelines recommend titration of oxygen to achieve a target oxygen saturation (SpO2) range. Information regarding whether this is being achieved is limited. METHODS: In this two-centre non-interventional study we used continuous pulse oximetry in acutely unwell medical patients over a 24-h period to determine the proportion of time spent with SpO2 within the prescribed target range and whether this is influenced by the target range, age, care in a high-dependency area and the number of oxygen adjustments. RESULTS: Eighty participants were included in the analysis. The mean (SD) proportion of time spent in target range was 55.6% (23.6), this was lower in those with a reduced hypercapnic target range (88-92% or below) compared to those with a range of 92-96%; difference - 13.1% (95% CI - 3.0 to - 23.2), P = 0.012. The proportion of time spent above range was 16.2% (22.9); this was higher in those with a reduced hypercapnic range; difference 21.6% (31.4 to 12), P < 0.001. The proportion of time below range was 28.4% (25.2); there was no difference between target ranges. The proportion of time spent in range was higher for those in a high dependency area in the multivariate model; difference 15.5% (95% CI 2.3 to 28.7), P = 0.02. CONCLUSIONS: Medical patients receiving oxygen in a ward setting spend significant periods of time with SpO2 both above and below the prescribed target range while receiving oxygen therapy.

[Factors predicting the need for invasive mechanical ventilation in patients with chronic obstructive pulmonary disease (COPD)]. / Facteurs prédictifs de la ventilation mécanique invasive chez les patients atteints de broncho-pneumopathie chronique obstructive (BPCO).

INTRODUCTION: the use of invasive mechanical ventilation (IMV) in acute exacerbations of chronic obstructive pulmonary disease (AECOPD) constitutes a negative turning point in the progression of the disease. The purpose of this study is to determine factors predicting the need for IMV in AECOPD. METHODS: we conducted a retrospective study by reviewing the medical records of patients with AECOPD hospitalized in our Department over a 18-year period (2000-2017). We compared 2 groups: G1: patients with AECOPD undergoing at least one IMV and G2: patients who had never undergone IMV following AECOPD. RESULTS: the study included 1152 patients with COPD: 133 in the G1 group (11.5%), and 1019 in the G2 group (88.5%). G1 patients were more symptomatic (p < 0.001), with more severe bronchial obstruction (p < 0.001). G1 patients had more exacerbations (p < 0.001), more hospitalizations and a higher need for non-invasive ventilation (NIV) (p < 0.001). Similarly, G1 patients more often developed chronic respiratory failure (p < 0.001) and had significantly lower survival rates. Independent risk factors associated with IMV were hypercapnia and decreased pH (in patients with severe AECOPD), a history of NIV, and chronic respiratory failure (CRF). CONCLUSION: respiratory function impairment, the severity of exacerbation and the need for NIV in a previous episode are factors predicting the need for IMV and poor outcomes.

[Impact of the duration of labor in the neonatal state measured by arterial blood gas at birth.] / Repercusión de la duración del parto en el estado neonatal medido a través de la gasometría arterial al nacimiento.

OBJECTIVE: The duration of labor has become a central axis of its clinical management, most of the studies that analyze its relationship with the neonatal state focus on indirect tests such as the Apgar test or admissions to the NICU. The aim of the study was to analyze the repercussions of the duration of labor on the condition of the neonates without added risk factors through a direct analysis test such as the umbilical artery blood gas test at birth. METHODS: An observational, analytical, retrospective, and prevalence study was conducted on a sample of 286 infants no previous risk factors obtained from the computerized clinical registry. For a confidence level of p<0.05, parametric tests such as Pearson's correlation coefficient and Chi-square were applied. RESULTS: Showed a significant negative correlation between umbilical artery pH values and delivery times (Dilation: R=-0.207; p=0.002 - Expulsive: R=-0.150; p=0.027 - Total delivery: R=-0.181; p=0.006). Presenting deliveries with times above the mean greater possibilities of fetal acidosis and hypercapnia in dilation (pH: OR=3.10; IC 1.64-5.51 - pCO2: OR=2.19; IC 1.23-3.89), the expulsive (pH: OR=2.24; IC 1.21-4.16 - pCO2: OR=1.77; IC 0.98-3.22) and the total duration (pH: OR=3.36, IC 1.84-6.13- pCO2: OR=2.53; IC 1.44-4.46). CONCLUSIONS: A significant association is was found between the prolongation of labor times and acidosis and neonatal hypercapnia.

OBJETIVO: La duración del parto se ha convertido en un eje central de su manejo clínico, la mayoría de estudios que analizan su relación con el estado neonatal se centra en pruebas indirectas como el test de Apgar o los ingresos en UCIN. El objetivo del estudio fue analizar las repercusiones de la duración del parto en el estado de los neonatos sin factores de riesgo añadidos a través de una prueba de análisis directo como es la gasometría de arteria umbilical al nacimiento. METODOS: Se diseñó un estudio observacional analítico, retrospectivo y de prevalencia realizado sobre una muestra de 286 neonatos sin factores de riesgo previos obtenida del registro clínico informático. Para un nivel de confianza de p<0,05 se aplicaron pruebas paramétricas como el coeficiente de correlación de Pearson y la Chi cuadrado. RESULTADOS: Mostraron una correlación significativa negativa entre los valores de pH de arteria umbilical y los tiempos del parto (Dilatación: R=-0,207; p=0,002 ­ Expulsivo: R=-0,150; p=0,027 - Totales de parto: R=-0,181; p=0,006). Presentando los partos con tiempos superiores a la media mayores posibilidades de acidosis fetal e hipercapnia en la dilatación (pH: OR=3,10; IC 1,64-5,51 - pCO2: OR=2,19; IC 1,23-3,89), el expulsivo (pH: OR=2,24; IC 1,21-4,16 - pCO2: OR=1,77; IC 0,98-3,22) y la duración total (pH: OR=3,36, IC 1,84-6,13- pCO2: OR=2,53; IC 1,44-4,46). CONCLUSIONES: Se constató una asociación significativa entre la prolongación de los tiempos del parto y la acidosis e hipercapnia neonatal.

Metabolic Complications Occur More Frequently in Older Patients Receiving Parenteral Nutrition.

BACKGROUND: The European Society for Clinical Nutrition and Metabolism Guidelines for Parenteral Nutrition in Geriatric Patients state metabolic complications are more frequent in elderly patients. However, literature provides limited information about metabolic complications in older patients receiving parenteral nutrition (PN). Consequently, the purpose of this study was to compare the development of metabolic complications in older vs younger patients receiving PN. METHODS: Patients receiving PN from May 1, 2014, to February 7, 2017, at Cooper University Hospital were included. Metabolic complications assessed included acid-base disturbances, hepatic complications, hypercapnia, hyperchloremia, hyperglycemia, hypernatremia, hypertriglyceridemia, hypochloremia, hypoglycemia, hypokalemia, hypophosphatemia, and refeeding syndrome. RESULTS: 595 patients were included (older group [≥65 years]: n = 245, median age: 76 years; younger group [<65 years]: n = 350, median age: 53 years]. Certain characteristics were similar between groups (female, 51%; mean body mass index of 28; critically ill, 34%; central PN, 97%; median duration of PN, 7 days; mean energy provision PN, 25.4 kcal/kg/d; mean dextrose infusion rate, 2.31 mg/kg/min). Overall, metabolic complications developed in 58% of patients and occurred more frequently in older vs younger patients (65.7% vs 53.4%; P = .003). Multivariate logistic analysis demonstrated increased odds of metabolic complications in the older group (odds ratio, 1.55; 95% CI, 1.014-2.375). CONCLUSIONS: Older hospitalized patients are more likely to develop a metabolic complication during their PN course than younger patients. This study heightens awareness that patients of advanced age are subject to metabolic complications; practitioners should anticipate and resolve complications in a timely manner.

The prevalence of hypercapnia during acute infection in children on chronic noninvasive ventilation: A retrospective study.

BACKGROUND/AIM: Children on chronic noninvasive ventilation are at risk for nonelective hospitalizations, mainly for acute infections. This study examined the prevalence of hypercapnia in children on chronic ventilatory support during an acute admission. METHODS: This retrospective study included children aged 0 to 18 years who regularly used bilevel positive airway pressure or continuous positive airway pressure at home, and who were diagnosed with an acute infection, and were hospitalized at the pediatrics department or pediatric intensive care unit. Capillary blood gas analysis and parameters of the built-in software of the home ventilator were recorded. RESULTS: Among the 43 cases included, hypercapnia was prevalent in 23% with a mean partial pressure of carbon dioxide of 51.7 ± 6.4 mm Hg. These children also had lower oxygen saturation levels. The respiratory rate 48 hours before admission was significantly higher in the hypercapnic group and the volume guarantee mode was less frequently used in the hypercapnic group. CONCLUSION: Approximately, a quarter of the cases of chronic home ventilation experience hypercapnia during an acute infection. Our data warrant a prospective study on the monitoring of respiratory rate in patients with chronic respiratory insufficiency as an indicator for hospitalizations with hypercapnia; we also recommend the use of volume guarantee mode of ventilation to prevent hypercapnia.

Prevalence of non-thyroidal illness syndrome in COPD exacerbation and effect of hypoxaemia and hypercapnia on thyroid functions.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease showing acute exacerbations during its course. Comorbidities often accompany. Non-thyroidal illness syndrome (NTIS) occurs because of the functional impairment in the hypothalamic-pituitary-thyroid axis in severe critical cases. The objective of the current study is to determine the prevalence of NTIS among hospitalised patients due to acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and to reveal the factors affecting thyroid functions. MATERIALS AND METHODS: A total of 132 patients hospitalised for AECOPD were enroled. Arterial blood gas samples at room air and venous blood samples for thyroid function tests were obtained within 24 hours following hospitalisation. RESULTS: The mean age was 69.3 ± 9.6 years with male predominance (M/F:130/2). The prevalence of NTIS was 55%. Subgroups of NTIS cases were analysed. Low TSH levels were the most common pathology (55%). Patients with NTIS had significantly lower PaO2 and SaO2 levels compared with those without NTIS (P = 0.045 and P = 0.022, respectively). In addition, a positive correlation was found between PaO2 and free thyroxine (fT4) (P < 0.001, r = 0.313). A statistically significant negative correlation between PaCO2 and fT4 was found (P < 0.001, r = -0.393). And a statistically significant negative correlation between PaCO2 and free triiodothyronine (fT3) values were found (P = 0.040, r = -0.183). CONCLUSION: NTIS is a very common condition during AECOPD. We believe that hypoxemia causing functional impairment in the hypothalamic-pituitary-thyroid axis is the main mechanism in NTIS development and hypercapnia disrupts freeT3 and freeT4 production and secretion.

Nocturnal hypercapnia with daytime normocapnia in patients with advanced pulmonary arterial hypertension awaiting lung transplantation.

BACKGROUND: Pulmonary arterial hypertension (PAH) is frequently complicated by sleep disordered breathing (SDB), and previous studies have largely focused on hypoxemic SDB. Even though nocturnal hypercapnia was shown to exacerbate pulmonary hypertension, the clinical significance of nocturnal hypercapnia among PAH patients has been scarcely investigated. METHOD: Seventeen patients with PAH were identified from 246 consecutive patients referred to Kyoto University Hospital for the evaluation of lung transplant registration from January 2010 to December 2017. Included in this study were 13 patients whose nocturnal transcutaneous carbon dioxide partial pressure (PtcCO2) monitoring data were available. Nocturnal hypercapnia was diagnosed according to the guidelines of the American Academy of Sleep Medicine. Associations of nocturnal PtcCO2 measurements with clinical features, the findings of right heart catheterization and pulmonary function parameters were evaluated. RESULTS: Nocturnal hypercapnia was diagnosed in six patients (46.2%), while no patient had daytime hypercapnia. Of note, nocturnal hypercapnia was found for 5 out of 6 patients with idiopathic PAH (83.3%). Mean nocturnal PtcCO2 levels correlated negatively with the percentage of predicted total lung capacity (TLC), and positively with cardiac output and cardiac index. CONCLUSION: Nocturnal hypercapnia was prevalent among advanced PAH patients who were waiting for lung transplantation, and associated with %TLC. Nocturnal hypercapnia was associated with the increase in cardiac output, which might potentially worsen pulmonary hypertension especially during sleep. Further studies are needed to investigate hemodynamics during sleep and to clarify whether nocturnal hypercapnia can be a therapeutic target for PAH patients.

Risk of Readmission and Mortality Following Hospitalization with Hypercapnic Respiratory Failure.

PURPOSE: Hypercapnic respiratory failure (HRF) is a frequent cause of hospitalization and a common comorbidity in hospitalized patients. There are few studies addressing what factors might predict poor outcomes in this patient population. The purpose of the current study was to investigate characteristics and outcomes of patients hospitalized with HRF. METHODS: A study of patients ≥ 18 years admitted with HRF in a 1-year period. Patients with limited life expectancy related to other conditions, and those with a non-respiratory cause of HRF, were excluded. RESULTS: 202 subjects met eligibility criteria: 24% had a diagnosis of obstructive sleep apnea, 6% obesity hypoventilation, 46% chronic obstructive pulmonary disease, and 10% asthma. Fifteen (7%) died during the index admission. Forty-one patients (23%) were readmitted within 30 days: peripheral vascular disease [adjusted odds ratio (aOR) 4.78, CI 1.45-15.74] and tachycardia (aOR 2.97, CI 1.22-7.26) were associated with an increased risk of readmission. Sixty-six patients (36%) died after discharge. Risk of death was increased in older patients (aOR 1.32, CI 1.13-1.54 per 5 years), those with peripheral vascular disease (aOR 12.56, CI 2.35-67.21), higher Charlson co-morbidity index (aOR 1.39, CI 1.09-1.76), use of home oxygen (aOR 4.03, CI 1.89-8.57), and those who had been readmitted (aOR 3.07, CI 1.46-6.43). CONCLUSIONS: Hospitalization for HRF is associated with a high morbidity and mortality. Our observation that home oxygen use was associated with increased mortality suggests that oxygen use could be a risk factor for death in patients with HRF.

Prevalence Of Chronic Hypercapnia In Severe Chronic Obstructive Pulmonary Disease: Data From The HOmeVent Registry.

Background: Non-invasive ventilation (NIV) has been shown to improve survival and quality of life in COPD patients with chronic hypercapnic respiratory failure. However, the proportion of COPD patients with chronic hypercapnia is not yet known and clinical data enabling better identification of patients are scarce. The HOmeVent registry was initiated to determine the prevalence of chronic hypercapnia in COPD in an outpatient setting and to evaluate the predictors of hypercapnia. Methods: HOmeVent is a multicenter, prospective, observational, non-interventional patient registry that includes COPD patients in GOLD stage 3 or 4. Eligible patients were identified and enrolled in an outpatient setting during routine clinic visits. Assessments included blood gas analyses, pulmonary function testing and quality of life assessment. Results: Ten outpatient clinics in Germany enrolled 231 COPD patients in the registry (135 in GOLD stage 3 (58%) and 96 in GOLD stage 4 (42%)). Arterial carbon dioxide pressure (PaCO2) was ≥45 mmHg in 58 patients (25%); of these, 20 (9%) had PaCO2 ≥50 mmHg. The prevalence of hypercapnia at both cut-off values was numerically higher for patients in GOLD stage 4 versus 3. An increased body mass index, a decreased forced vital capacity and an increased bicarbonate level were significant independent predictors of hypercapnia. The proportion of patients who received NIV was 6% overall and 22% of those with hypercapnia. Conclusion: A relevant proportion of COPD patients in GOLD stage 3 and 4 exhibits chronic hypercapnia and might, therefore, be candidates for long-term domiciliary NIV treatment.

Oxygen alert wristbands (OxyBand) and controlled oxygen: a pilot study.

Despite the introduction of Oxygen Alert Cards, guidelines and audits, oxygen therapy remains overused in NHS practice, and this may lead to iatrogenic mortality. This pilot study aimed to examine the use of Oxygen Alert Wristbands (OxyBand) designed to alert health professionals who are delivering oxygen to patients to ensure that the oxygen is administered and titrated safely to the appropriate target saturations. Patients at risk of hypercapnic acidosis were asked to wear OxyBands while presenting to paramedics and health professionals in hospitals. Inappropriate prescription of oxygen reduced significantly after the OxyBands were used. A questionnaire-based assessment showed that the clinicians involved had a good understanding of the risks of uncontrolled oxygen. Forty-two patients found the wrist band comfortable to wear, and only two did not. OxyBands may have the potential to improve patient safety over Oxygen Alert Cards.

Obesity hypoventilation syndrome.

Obesity hypoventilation syndrome (OHS) is defined as a combination of obesity (body mass index ≥30 kg·m-2), daytime hypercapnia (arterial carbon dioxide tension ≥45 mmHg) and sleep disordered breathing, after ruling out other disorders that may cause alveolar hypoventilation. OHS prevalence has been estimated to be ∼0.4% of the adult population. OHS is typically diagnosed during an episode of acute-on-chronic hypercapnic respiratory failure or when symptoms lead to pulmonary or sleep consultation in stable conditions. The diagnosis is firmly established after arterial blood gases and a sleep study. The presence of daytime hypercapnia is explained by several co-existing mechanisms such as obesity-related changes in the respiratory system, alterations in respiratory drive and breathing abnormalities during sleep. The most frequent comorbidities are metabolic and cardiovascular, mainly heart failure, coronary disease and pulmonary hypertension. Both continuous positive airway pressure (CPAP) and noninvasive ventilation (NIV) improve clinical symptoms, quality of life, gas exchange, and sleep disordered breathing. CPAP is considered the first-line treatment modality for OHS phenotype with concomitant severe obstructive sleep apnoea, whereas NIV is preferred in the minority of OHS patients with hypoventilation during sleep with no or milder forms of obstructive sleep apnoea (approximately <30% of OHS patients). Acute-on-chronic hypercapnic respiratory failure is habitually treated with NIV. Appropriate management of comorbidities including medications and rehabilitation programmes are key issues for improving prognosis.

Role of venous blood gases in hypercapnic respiratory failure chronic obstructive pulmonary disease patients presenting to the emergency department.

BACKGROUND: Many patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have type 2 respiratory failure (T2RF). Often arterial blood gases are not performed and correlation with venous blood gases (VBG) is controversial. The venous pH and bicarbonate (HCO3 ) are useful, but VBG pCO2 (PvCO2 ) is considered too unpredictable. AIM: To examine the utility of VBG in this cohort of patients. METHODS: A prospective study of AECOPD patients with T2RF presenting to the emergency department was performed. Patients being considered for non-invasive ventilation and who required an arterial blood gas were invited to participate. A subsequent VBG was also taken, and Bland-Altman plots were used for analysis. RESULTS: Sixty-three patients were included in this study. The limits of agreement for pH and HCO3 were narrow. Wider limits of agreement with a systematic bias of 7.7 mmHg were noted with pCO2 . CONCLUSIONS: The utility of VBG pH and HCO3 was again demonstrated. VBG pCO2 in this cohort of patients may have a role in the assessment of patients with AECOPD. Further study is needed on the possible role of VBG in the management of such patients with T2RF particularly those using non-invasive ventilation.

Vasopressin during Laparoscopic Myomectomy: Does It Really Extend Its Limits?

STUDY OBJECTIVE: Τo investigate whether the use of vasopressin played an important role in the safe expansion of the indications of laparoscopic myomectomy in our practice. DESIGN: A retrospective comparison of prospectively collected data (Canadian Task Force classification II2). SETTING: A gynecologic endoscopy unit in a tertiary university hospital. PATIENTS: One hundred fifty patients undergoing laparoscopic myomectomy; 50 were treated without the use of any vasoconstrictive agent (group 1), and 100 were treated with intraoperative intramyometrial injection of dilute vasopressin (20 IU/100 mL normal saline) (group 2). INTERVENTIONS: Laparoscopic myomectomy. MEASUREMENTS AND MAIN RESULTS: We compared the 2 groups in terms of size, number, and type of myomas; estimated blood loss (EBL); procedure length; transfusion rates; laparoconversion rates; and rates of complications. Two cases in group 1 (4%) were laparoconverted versus none (0%) in group 2. Overall, the mean EBL was 321.8 ± 246.0 mL in group 1 compared with 147.8 ± 171.8 mL in group 2, respectively (p <.001). Additionally, EBL was significantly lower in the vasopressin group in all of the study's subgroups of patients stratified according to the size and number of myomas. Procedure length did not differ significantly between the 2 groups (130.8 ± 49.5 vs 115.6 ± 49.4 minutes, p = .078). The risk factors for prolongation of the procedure included size and number of myomas independently of vasopressin. The rates of hypercapnea and subcutaneous emphysema were higher in group 1. The risk factors for hypercapnea and subcutaneous emphysema included the size and intramural position of the largest myoma. Vasopressin was not associated with serious cardiovascular adverse events. CONCLUSIONS: Vasopressin is effective in reducing blood loss during laparoscopic myomectomy. Although experienced surgeons may achieve comparable operation times without vasopressin, even in the most challenging cases, blood loss may still be considerable. The occurrence of hypercapnea is higher in untreated cases and may contribute to laparoconversion.

Defining the criteria for intubation of the patient with thermal burns.

OBJECTIVES: Recent studies demonstrate that burn patients are undergoing unnecessary intubations. We sought to determine the clinical criteria that predict intubations with benefit. METHODS: This was a retrospective review of intubated adults admitted to our center with thermal burns 2008-2013. Criteria for intubation were defined as traditional criteria (suspected smoke inhalation, oropharynx soot, hoarseness, dysphagia, singed facial hair, oral edema, oral burn, non-full thickness facial burns), or ABA criteria as defined by the 2011 ABA guidelines (full thickness facial burns, stridor, respiratory distress, swelling on laryngoscopy, upper airway trauma, altered mentation, hypoxia/hypercarbia, hemodynamic instability). Patients with <26days free from mechanical ventilation (ventilator-free days (VFD)) out of 28, were deemed indicated long-term intubations. Those with ≥26 VFD were deemed unnecessary short-term intubations. RESULTS: Of 218 patients, 151 had long-term and 67 had short-term intubations. Long-term intubation was strongly associated with ABA criteria (77.5%) compared to traditional criteria (22.5%) (p<0.001). Sensitivity of ABA criteria for long-term intubation was 77% and specificity 46%. Traditional criteria associated with long-term intubation included suspected smoke inhalation (OR 2.45 [95% CI, 1.18-5.11]), and singed facial hair (OR 2.53 [95% CI, 1.25-5.09]). The addition of these to ABA criteria created the Denver criteria, which exhibited an increased sensitivity for long-term intubations (95%), but decreased specificity (24%). CONCLUSIONS: Intubation should be considered for patients displaying the Denver criteria, which includes full thickness facial burns, stridor, respiratory distress, swelling on laryngoscopy, upper airway trauma, altered mentation, hypoxia/hypercarbia, hemodynamic instability, suspected smoke inhalation, and singed facial hair. Patients lacking these criteria should not be intubated.

Association of Hypercapnia and Hypercapnic Acidosis With Clinical Outcomes in Mechanically Ventilated Patients With Cerebral Injury.

Importance: Clinical studies investigating the effects of hypercapnia and hypercapnic acidosis in acute cerebral injury are limited. The studies performed so far have mainly focused on the outcomes in relation to the changes in partial pressure of carbon dioxide and pH in isolation and have not evaluated the effects of partial pressure of carbon dioxide and pH in conjunction. Objective: To review the association of compensated hypercapnia and hypercapnic acidosis during the first 24 hours of intensive care unit admission on hospital mortality in adult mechanically ventilated patients with cerebral injury. Design, Setting, and Participants: Multicenter, binational retrospective review of patients with cerebral injury (traumatic brain injury, cardiac arrest, and stroke) admitted to 167 intensive care units in Australia and New Zealand between January 2000 and December 2015. Patients were classified into 3 groups based on combination of arterial pH and arterial carbon dioxide (normocapnia and normal pH, compensated hypercapnia, and hypercapnic acidosis) during the first 24 hours of intensive care unit stay. Main Outcomes and Measures: Hospital mortality. Results: A total of 30 742 patients (mean age, 55 years; 21 827 men [71%]) were included. Unadjusted hospital mortality rates were highest in patients with hypercapnic acidosis. Multivariable logistic regression analysis and Cox proportional hazards analysis in 3 diagnostic categories showed increased odds of hospital mortality (cardiac arrest odds ratio [OR], 1.51; 95% CI, 1.34-1.71; stroke OR, 1.43; 95% CI, 1.27-1.6; and traumatic brain injury OR, 1.22; 95% CI, 1.06-1.42; P <.001) and hazard ratios (HR) (cardiac arrest HR, 1.23; 95% CI, 1.14-1.34; stroke HR, 1.3; 95% CI, 1.21-1.4; traumatic brain injury HR, 1.13; 95% CI, 1-1.27), in patients with hypercapnic acidosis compared with normocapnia and normal pH. There was no difference in mortality between patients who had compensated hypercapnia compared with patients who had normocapnia and normal pH. In patients with hypercapnic acidosis, the adjusted OR of hospital mortality increased with increasing partial pressure of carbon dioxide, while no such increase was noted in patients with compensated hypercapnia. Conclusions and Relevance: Hypercapnic acidosis was associated with increased risk of hospital mortality in patients with cerebral injury. Hypercapnia, when compensated to normal pH during the first 24 hours of intensive care unit admission, may not be harmful in mechanically ventilated patients with cerebral injury.

Influence of PCO2 Control on Clinical and Neurodevelopmental Outcomes of Extremely Low Birth Weight Infants.

BACKGROUND: Levels or fluctuations in the partial pressure of CO2 (PCO2) may affect outcomes for extremely low birth weight infants. OBJECTIVES: In an exploratory analysis of a randomized trial, we hypothesized that the PCO2 values achieved could be related to significant outcomes. METHODS: On each treatment day, infants were divided into 4 groups: relative hypocapnia, normocapnia, hypercapnia, or fluctuating PCO2. Ultimate assignment to a group for the purpose of this analysis was made according to the group in which an infant spent the most days. Statistical analyses were performed with analysis of variance (ANOVA), the Kruskal-Wallis test, the χ2 test, and the Fisher exact test as well as by multiple logistic regression. RESULTS: Of the 359 infants, 57 were classified as hypocapnic, 230 as normocapnic, 70 as hypercapnic, and 2 as fluctuating PCO2. Hypercapnic infants had a higher average product of mean airway pressure and fraction of inspired oxygen (MAP × FiO2). For this group, mortality was higher, as was the likelihood of having moderate/severe bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), and poorer neurodevelopment. Multiple logistic regression analyses showed an increased risk for BPD or death associated with birth weight (p < 0.001) and MAP × FiO2 (p < 0.01). The incidence of adverse neurodevelopment was associated with birth weight (p < 0.001) and intraventricular hemorrhage (IVH; p < 0.01). CONCLUSIONS: Birth weight and respiratory morbidity, as measured by MAP × FiO2, were the most predictive of death or BPD and NEC, whereas poor neurodevelopmental outcome was associated with low birth weight and IVH. Univariate models also identified PCO2. Thus, hypercapnia seems to reflect greater disease severity, a likely contributor to differences in outcomes.