Detection of Chronic Hypoventilation Among Infants With Robin Sequence Using Capillary Blood Gas Sampling.

OBJECTIVES/HYPOTHESIS: To describe the use of capillary blood gas (CBG) sampling to detect and quantify hypoventilation in infants with Robin sequence (RS). METHODS: Case series with chart review at two institutions. Infants with RS presenting over a 10-year period were identified using departmental databases. CBG values obtained during infancy or until airway intervention (AI) were reviewed. RESULTS: From 2008 to 2018, 111 infants with RS were identified as having had been assessed and managed from birth or transfer until discharge home and having CBG data available. In most cases, CBG sampling was obtained every other day until intervention or discharge. A total of 81 (73%) infants required AI: 72 (89%) underwent mandibular distraction osteogenesis, five (6%) underwent tracheotomy, and four (5%) were discharged home with a nasopharyngeal airway. The mean PCO2 at day of life (DOL) 7-30 for the AI group was 52.7 mmHg (95% confidence interval: 51.7-53.7) and for the no AI group was 45.9 mmHg (44.8-47.0; P < .0001). The mean HCO3 at DOL 7-30 for the AI group was 29.8 mEq/L (29.4-30.1) and for the no AI group was 27.0 mEq/L (26.5-27.4; P < .0001). Receiver operating characteristic curves were created for maximum PCO2 and HCO3 values and cutoffs were established by optimizing a balance of sensitivity and specificity. Infants requiring AI surpassed the PCO2 and HCO3 cutoff at a median of DOL 9. CONCLUSIONS: Among infants with RS and hypoventilation, objective measures of respiratory acidosis may be apparent by DOL 9. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:2789-2794, 2021.

Comparison of volume-controlled, pressure-controlled, and pressure-controlled volume-guaranteed ventilation during robot-assisted laparoscopic gynecologic surgery in the Trendelenburg position.

Background: Pressure-controlled ventilation volume-guaranteed (PCV-VG) is being increasingly used for ventilation during general anesthesia. Carbon dioxide (CO2) pneumoperitoneum in the Trendelenburg position is routinely used during robot-assisted laparoscopic gynecologic surgery. Here, we hypothesized that PCV-VG would reduce peak inspiratory pressure (Ppeak), compared to volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV). Methods: In total, 60 patients were enrolled in this study and randomly assigned to receive VCV, PCV, or PCV-VG. Hemodynamic variables, respiratory variables, and arterial blood gases were measured in the supine position 15 minutes after the induction of anesthesia (T0), 30 and 60 minutes after CO2 pneumoperitoneum and Trendelenburg positioning (T1 and T2, respectively), and 15 minutes after placement in the supine position at the end of anesthesia (T3). Results: The Ppeak was higher in the VCV group than in the PCV and PCV-VG groups (p=0.011). Mean inspiratory pressure (Pmean) was higher in the PCV and PCV-VG groups than in the VCV group (p<0.001). Dynamic lung compliance (Cdyn) was lower in the VCV group than in the PCV and PCV-VG groups (p=0.001). Conclusion: Compared to VCV, PCV and PCV-VG provided lower Ppeak, higher Pmean, and improved Cdyn, without significant differences in hemodynamic variables or arterial blood gas results during robot-assisted laparoscopic gynecologic surgery with Trendelenburg position.

The effect of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) severity on cellular bioenergetic function.

Myalgic encephalomyelitis/ Chronic fatigue syndrome (ME/CFS) has been associated with abnormalities in mitochondrial function. In this study we have analysed previous bioenergetics data in peripheral blood mononuclear cells (PBMCs) using new techniques in order to further elucidate differences between ME/CFS and healthy control cohorts. We stratified our ME/CFS cohort into two individual cohorts representing moderately and severely affected patients in order to determine if disease severity is associated with bioenergetic function in PBMCs. Both ME/CFS cohorts showed reduced mitochondrial function when compared to a healthy control cohort. This shows that disease severity does not correlate with mitochondrial function and even those with a moderate form of the disease show evidence of mitochondrial dysfunction. Equations devised by another research group have enabled us to calculate ATP-linked respiration rates and glycolytic parameters. Parameters of glycolytic function were calculated by taking into account respiratory acidification. This revealed severely affected ME/CFS patients to have higher rates of respiratory acidification and showed the importance of accounting for respiratory acidification when calculating parameters of glycolytic function. Analysis of previously published glycolysis data, after taking into account respiratory acidification, showed severely affected patients have reduced glycolysis compared to moderately affected patients and healthy controls. Rates of ATP-linked respiration were also calculated and shown to be lower in both ME/CFS cohorts. This study shows that severely affected patients have mitochondrial and glycolytic impairments, which sets them apart from moderately affected patients who only have mitochondrial impairment. This may explain why these patients present with a more severe phenotype.

Inadequacy of Pulse Oximetry in the Catheterization Laboratory. An Exploratory Study Monitoring Respiratory Status Using Arterial Blood Gases during Cardiac Catheterization with Conscious Sedation.

BACKGROUND: Benzodiazepines and opioids are commonly used for conscious sedation (CS) in cardiac catheterization laboratory (CCL) patients. Both drugs are known to predispose to hypoxemia, apnea and decreased responsiveness to PCO2, resulting in decreased arterial pH and PO2, as well as increased PCO2. We want to determine the effects of CS on arterial blood gas (ABG) in CCL patient, and identify if pulse oximetry monitoring is adequate. METHODS: We enrolled 18 subjects undergoing elective catheterization. Measurement of ABGs at one-minute intervals was done from the moment of arterial access until case end. The results of ABGs were not available to the clinician who administered sedation. Relationships of pH, PCO2, PaO2 and SaO2 were studied by plotting time series graphs. Significant changes were defined as pH <7.30, SaO2 < 90, and PCO2 > 50 mmHg. RESULTS: No significant change in pH, PCO2, PaO2 and SaO2 was noted in 4/18 (22%) subjects. A significant drop in SaO2 was noted in 4/18 (22%). A significant change in PCO2 and/or pH was noted in 10/18 (55%) cases. Among the 16 (16/18) subjects receiving supplemental oxygen, 7 (7/18, 39%) had no drop in SaO2, but developed respiratory acidosis. At the end of the case, 5/18 (28%) subjects had respiratory acidosis with normal PaO2. CONCLUSION: Significant hypercarbia and acidosis occurred frequently in this small study during CS in patients undergoing cardiac catheterization. Relying on pulse oximetry alone especially with patients on supplemental oxygen may lead to failure in detecting respiratory acidosis in a significant number of patients.

A Quick Reference on Respiratory Acidosis.

Respiratory acidosis, or primary hypercapnia, occurs when carbon dioxide production exceeds elimination via the lung and is mainly owing to alveolar hypoventilation. Concurrent increases in Paco2, decreases in pH and compensatory increases in blood HCO3- concentration are associated with respiratory acidosis. Respiratory acidosis can be acute or chronic, with initial metabolic compensation to increase HCO3- concentrations by intracellular buffering. Chronic respiratory acidosis results in longer lasting increases in renal reabsorption of HCO3-. Alveolar hypoventilation and resulting respiratory acidosis may also be associated with hypoxemia, especially evident when patients are inspiring room air (20.9% O2).

Respiratory Acid-Base Disorders in the Critical Care Unit.

The incidence of respiratory acid-base abnormalities in the critical care unit (CCU) is unknown, although respiratory alkalosis is suspected to be common in this population. Abnormal carbon dioxide tension can have many physiologic effects, and changes in Pco2 may have a significant impact on outcome. Monitoring Pco2 in CCU patients is an important aspect of critical patient assessment, and identification of respiratory acid-base abnormalities can be valuable as a diagnostic tool. Treatment of respiratory acid-base disorders is largely focused on resolution of the primary disease, although mechanical ventilation may be indicated in cases with severe respiratory acidosis.

Use of Elements of the Stewart Model (Strong Ion Approach) - SID3, SID4, Atot/A-, SIDe and SIG for the Diagnostics of Respiratory Acidosis in Brachycephalic Dogs.

Buffer systems of blood and tissues, which have the ability to bind with and give up hydrogen ions, participate in maintaining the acid-base balance (ABB) of the organism. According to the classic model, the system of carbonic acid and bicarbonates, where the first component serves the role of an acid and the second a base, determines plasma pH. The so-called Stewart model, which assumes that ions in blood serum can be separated into completely dissociated - nonbuffer and not dissociated - buffer ions which may give up or accept H+ions, also describes the ABB of the organism. The goal of the study was to find out whether, during respiratory acidosis, the values of SID3, SID4, Atot/A-, SIDe and SIG change. The study was carried out on 60 adult dogs of the boxer breed (32 males and 28 females) in which, on the basis of an arterial blood test, respiratory acidosis was found. A strong overgrowth of the soft palate tissue requiring a surgical correction was the cause of the ABB disorder. Prior to surgery and on the 14th day after the surgery, venous and arterial blood was drawn from each dog. ABB parameters were determined in the arterial blood sample: the blood pH, pCO2 and HCO3-. In the venous blood, concentration of Na+, K+, Cl-, lactate-, albumins, and Pinorganic was determined. On the basis of the obtained data, the values of SID3, SID4, SIDe, A- and SIG, before and after the surgery, were calculated. In spite of the fact that the average concentration of ions, albumins, Pinorganic and lactate in the blood serum of dogs before and after the surgical procedure was similar and within the physiological norms, the values of SID3, SIDe and SIG, calculated on the basis of the former, displayed statistically significant differences. CONCLUSION: On the basis of the results obtained, it can be stated that the values of SID3, SIDe and SIG change during respiratory acidosis and may be helpful in the diagnostics of ABB disorders in brachycephalic dogs.

Blood Gas Analyzers.

Acid-base and respiratory disturbances are common in sick and hospitalized veterinary patients; therefore, blood gas analyzers have become integral diagnostic and monitoring tools. This article will discuss uses of blood gas analyzers, types of samples that can be used, sample collection methods, potential sources of error, and potential alternatives to blood gas analyzers and their limitations. It will also discuss the types of analyzers that are available, logistical considerations that should be taken into account when purchasing an analyzer, and the basic principles of how these analyzers work.

Differences in baseline factors and survival between normocapnia, compensated respiratory acidosis and decompensated respiratory acidosis in COPD exacerbation: A pilot study.

BACKGROUND AND OBJECTIVE: Patients with chronic obstructive pulmonary disease (COPD) experiencing acute exacerbation (AE-COPD) with decompensated respiratory acidosis are known to have poor outcomes in terms of recurrent respiratory failure and death. However, the outcomes of AE-COPD patients with compensated respiratory acidosis are not known. METHODS: We performed a 1-year prospective, single-centre, cohort study in patients surviving the index admission for AE-COPD to compare baseline factors between groups with normocapnia, compensated respiratory acidosis and decompensated respiratory acidosis. Survival analysis was done to examine time to readmissions, life-threatening events and death. RESULTS: A total of 250 patients fulfilling the inclusion and exclusion criteria were recruited and 245 patients were analysed. Compared with normocapnia, both compensated and decompensated respiratory acidosis are associated with lower FEV1 % (P < 0.001), higher GOLD stage (P = 0.003, <0.001) and higher BODE index (P = 0.038, 0.001) and a shorter time to life-threatening events (P < 0.001). Comparing compensated and decompensated respiratory acidosis, there was no difference in FEV1 (% predicted) (P = 0.15), GOLD stage (P = 0.091), BODE index (P = 0.158) or time to life-threatening events (P = 0.301). High PaCO2 level (P = 0.002) and previous use of non-invasive ventilation (NIV) in acute setting (P < 0.001) are predictive factors of future life-threatening events by multivariate analysis. CONCLUSIONS: Compared with normocapnia, both compensated and decompensated respiratory acidosis are associated with poorer lung function and higher risk of future life-threatening events. High PaCO2 level and past history of NIV use in acute settings were predictive factors for future life-threatening events. Compensated respiratory acidosis warrants special attention and optimization of medical therapy as it poses risk of life-threatening events.

The use of elements of the Stewart model (Strong Ion Approach) for the diagnostics of respiratory acidosis on the basis of the calculation of a value of a modified anion gap (AGm) in brachycephalic dogs.

UNLABELLED: Apart from the HH equation, the acid-base balance of an organism is also described by the Stewart model, which assumes that the proper insight into the ABB of the organism is given by an analysis of: pCO2, the difference of concentrations of strong cations and anions in the blood serum - SID, and the total concentration of nonvolatile weak acids - Acid total. The notion of an anion gap (AG), or the apparent lack of ions, is closely related to the acid-base balance described according to the HH equation. Its value mainly consists of negatively charged proteins, phosphates, and sulphates in blood. In the human medicine, a modified anion gap is used, which, including the concentration of the protein buffer of blood, is, in fact, the combination of the apparent lack of ions derived from the classic model and the Stewart model. In brachycephalic dogs, respiratory acidosis often occurs, which is caused by an overgrowth of the soft palate, making it impossible for a free air flow and causing an increase in pCO2--carbonic acid anhydride The aim of the present paper was an attempt to answer the question whether, in the case of systemic respiratory acidosis, changes in the concentration of buffering ions can also be seen. The study was carried out on 60 adult dogs of boxer breed in which, on the basis of the results of endoscopic examination, a strong overgrowth of the soft palate requiring a surgical correction was found. For each dog, the value of the anion gap before and after the palate correction procedure was calculated according to the following equation: AG = ([Na+ mmol/l] + [K+ mmol/l])--([Cl- mmol/l]+ [HCO3- mmol/l]) as well as the value of the modified AG--according to the following equation: AGm = calculated AG + 2.5 x (albumins(r)--albumins(d)). The values of AG calculated for the dogs before and after the procedure fell within the limits of the reference values and did not differ significantly whereas the values of AGm calculated for the dogs before and after the procedure differed from each other significantly. CONCLUSIONS: 1) On the basis of the values of AGm obtained it should be stated that in spite of finding respiratory acidosis in the examined dogs, changes in ion concentration can also be seen, which, according to the Stewart theory, compensate metabolic ABB disorders 2) In spite of the fact that all the values used for calculation of AGm were within the limits of reference values, the values of AGm in dogs before and after the soft palate correction procedure differed from each other significantly, which proves high sensitivity and usefulness of the AGm calculation as a diagnostic method.

Robotic prostatectomy: the anesthetist's view for robotic urological surgeries, a prospective study / Prostatectomia robótica: análise anestesiológica de cirurgias urológicas robóticas: estudo prospectivo / Prostatectomía robótica: análisis anestesiológico de cirugías urológicas robóticas, un estudio prospectivo

Background and objectives: Although many features of robotic prostatectomy are similar to those of conventional laparoscopic urological procedures (such as laparoscopic prostatectomy), the procedure is associated with some drawbacks, which include limited intravenous access, relatively long operating time, deep Trendelenburg position, and high intra-abdominal pressure. The primary aim was to describe respiratory and hemodynamic challenges and the complications related to high intra-abdominal pressure and the deep Trendelenburg position in robotic prostatectomy patients. The secondary aim was to reveal safe discharge criteria from the operating room. Methods: Fifty-three patients who underwent robotic prostatectomy between December 2009 and January 2011 were prospectively enrolled. Main outcome measures were non-invasive monitoring, invasive monitoring and blood gas analysis performed at supine (T0), Trendelenburg (T1), Trendelenburg + pneumoperitoneum (T2), Trendelenburg-before desufflation (T3), Trendelenburg (after desufflation) (T4), and supine (T5) positions. Results: Fifty-three robotic prostatectomy patients were included in the study. The main clinical challenge in our study group was the choice of ventilation strategy to manage respiratory acidosis, which is detected through end-tidal carbon dioxide pressure and blood gas analysis. Furthermore, the mean arterial pressure remained unchanged, the heart rate decreased significantly and required intervention. The central venous pressure values were also above the normal limits. Conclusion: Respiratory acidosis and "upper airway obstruction-like" clinical symptoms were the main challenges associated with robotic prostatectomy procedures during this study. .

Justificativa e objetivos: Embora muitas características da prostatectomia robótica sejam semelhantes àquelas de laparoscopias urológicas convencionais (como a prostatectomia por laparoscopia), o procedimento está associado a alguns inconvenientes, incluindo acesso intravenoso limitado, tempo cirúrgico relativamente longo, posição de Trendelenburg profunda e pressão intra-abdominal alta. O objetivo principal foi descrever as alterações respiratória e hemodinâmica e as complicações relacionadas à pressão intra-abdominal elevada e à posição de Trendelenburg profunda em pacientes submetidos à prostatectomia robótica. O objetivo secundário foi revelar critérios seguros de alta do centro cirúrgico. Métodos: Foram inscritos prospectivamente 53 pacientes submetidos à prostatectomia robótica entre dezembro de 2009 e janeiro de 2011. As medidas de desfecho primário foram: monitoramento não invasivo, monitoramento invasivo e gasometria feita em decúbito dorsal (T0), Trendelenburg (T1), Trendelenburg + pneumoperitônio (T2), Trendelenburg pré-desinsuflação (T3), Trendelenburg pós-desinsuflação (T4) e posições supinas (T5). Resultados: O principal desafio clínico em nosso grupo de estudo foi a escolha da estratégia de ventilação para controlar a acidose respiratória, que é detectada por meio da pressão de dióxido de carbono expirado e da gasometria. Além disso, a pressão arterial média permaneceu inalterada e a frequência cardíaca diminuiu significativamente e precisou de intervenção. Os valores da pressão venosa central também estavam acima dos limites normais. Conclusão: A acidose respiratória e sintomas clínicos "semelhantes à obstrução ...

Justificación y objetivos: Aunque muchas características de la prostatectomía robótica sean similares a las de las laparoscopias urológicas convencionales (como la prostatectomía laparoscópica), el procedimiento está asociado con algunos inconvenientes, incluyendo el acceso intravenoso limitado, tiempo quirúrgico relativamente largo, posición de Trendelenburg profunda y presión intraabdominal alta. El objetivo principal fue describir las alteraciones respiratorias y hemodinámicas y las complicaciones relacionadas con la presión intraabdominal elevada y con la posición de Trendelenburg profunda en pacientes sometidos a prostatectomía robótica. El objetivo secundario fue revelar criterios seguros de alta del quirófano. Métodos: Cincuenta y tres pacientes sometidos a prostatectomía robótica entre diciembre de 2009 y enero de 2011 fueron incluidos en un estudio prospectivo. Las principales medidas de resultado fueron: monitorización no invasiva, monitorización invasiva y gasometría realizada en decúbito dorsal (T0), Trendelenburg (T1), Trendelenburg + neumoperitoneo (T2), Trendelenburg predesinsuflación (T3), Trendelenburg posdesinsuflación (T4) y posiciones supinas (T5). Resultados: Cincuenta y tres pacientes sometidos a prostatectomía robótica fueron incluidos en el estudio. El principal reto clínico en nuestro grupo de estudio fue la elección de la estrategia de ventilación para controlar la acidosis respiratoria, que es detectada por medio de la presión de dióxido de carbono espirado y la gasometría. Además, la presión arterial media permaneció inalterada, y la frecuencia cardíaca disminuyó significativamente y fue necesario intervenir. Los valores de la presión venosa central también estaban por encima de los límites normales. ...

[Practical diagnostics of acid-base disorders: part I: differentiation between respiratory and metabolic disturbances]. / Praktische Diagnostik des Säure-Base-Haushalts : Teil 1: Differenzierung von respiratorischen und metabolischen Störungen.

The first part of this overview on diagnostic tools for acid-base disorders focuses on basic knowledge for distinguishing between respiratory and metabolic causes of a particular disturbance. Rather than taking sides in the great transatlantic or traditional-modern debate on the best theoretical model for understanding acid-base physiology, this article tries to extract what is most relevant for everyday clinical practice from the three schools involved in these keen debates: the Copenhagen, the Boston and the Stewart schools. Each school is particularly strong in a specific diagnostic or therapeutic field. Appreciating these various strengths a unifying, simplified algorithm together with an acid-base calculator will be discussed.

Simple acid-base tutorial.

The nutrition support practitioner is confronted with numerous metabolic abnormalities in the daily care of patients. An understanding of the basic principles of acid-base balance, along with the ability to recognize common causes of the various disorders, enhances the clinician's ability to provide specialized nutrition support. The basic metabolic and respiratory disorders, along with common causes, are reviewed in this tutorial.

Respiratory acidosis in adolescents with anorexia nervosa hospitalized for medical stabilization: a retrospective study.

OBJECTIVE: To examine the effect of malnutrition due to anorexia nervosa (AN) on venous blood gases of adolescents with AN hospitalized for medical stabilization. METHOD: This retrospective study included 45 adolescents with recent onset (<1 year) AN diagnosed by DSM-IV criteria and excluded subjects with a history of lung disease. RESULTS: Mean (± SD) age at hospitalization was 15.0 ± 2.0 years; time from onset of symptoms was 6.8 ± 3.0 months; body mass index (BMI) was 15.2 ± 1.5 kg/m(2) ; and minimal nocturnal heart rate (MNHR) was 39.8 ± 7.2 beats/min. On admission, pH was 7.32 ± 0.02, pCO(2) was 53.8 ± 4.6 mm Hg, and HCO(3) was 28.1 ± 2.1 mEq/l. Significant changes (p < .001) occurred during the relatively short hospitalization (9.7 ± 5.1 days): venous pH increased, pCO(2) decreased, HCO(3) decreased, MNHR increased, and heart rate orthostasis decreased. Mild respiratory acidosis (pH < 7.35 and pCO(2) > 45 mm Hg) was observed in 78% of the patients on admission and only in 35% at discharge (p = .0003). Positive correlations were found between % of weight loss and pCO(2) on admission and between BMI on admission and the delta pCO(2) during hospitalization. DISCUSSION: Mild respiratory acidosis is common in adolescents with recently diagnosed AN, hospitalized for medical stabilization. Respiratory acidosis improves with bed rest and refeeding. The clinical significance of these findings should be further evaluated.