Pressure Of Carbon Dioxide Levels Research Articles

Non-invasive high-frequency oscillatory ventilation (NHFOV) versus nasal continuous positive airway pressure (NCPAP) for preterm infants: a systematic review and meta-analysis

ObjectiveTo compare the efficacy and safety of non-invasive high-frequency oscillatory ventilation (NHFOV) and nasal continuous positive airway pressure (NCPAP) in preterm infants.DesignThe study conducted a comprehensive analysis across three databases,...

Hypercapnia Causes Injury of the Cerebral Cortex and Cognitive Deficits in Newborn Piglets.

In critically ill newborns, exposure to hypercapnia (HC) is common and often accepted in neonatal intensive care units to prevent severe lung injury. However, as a "safe" range of arterial partial pressure of carbon dioxide levels in neonates has not been established, the potential impact of HC on the neurodevelopmental outcomes in these newborns remains a matter of concern. Here, in a newborn Yorkshire piglet model of either sex, we show that acute exposure to HC induced persistent cortical neuronal injury, associated cognitive and learning deficits, and long-term suppression of cortical electroencephalogram frequencies. HC induced a transient energy failure in cortical neurons, a persistent dysregulation of calcium-dependent proapoptotic signaling in the cerebral cortex, and activation of the apoptotic cascade, leading to nuclear deoxyribonucleic acid fragmentation. While neither 1 h of HC nor the rapid normalization of HC was associated with changes in cortical bioenergetics, rapid resuscitation resulted in a delayed onset of synaptosomal membrane lipid peroxidation, suggesting a dissociation between energy failure and the occurrence of synaptosomal lipid peroxidation. Even short durations of HC triggered biochemical responses at the subcellular level of the cortical neurons resulting in altered cortical activity and impaired neurobehavior. The deleterious effects of HC on the developing brain should be carefully considered as crucial elements of clinical decisions in the neonatal intensive care unit.

Efficacy and Safety Evaluation of Different Maintenance Dose Regimens of Caffeine Citrate in the Treatment of Primary Apnea in Preterm Infants

We have investigated the efficacy and safety of different maintenance doses of caffeine citrate in the treatment of primary apnea in preterm infants. To this end, apneic premature infants were treated with 5 mg/kg (low dose) or 10 mg/kg (high dose) caffeine citrate, and the frequency of apnea at 48 h and 72 h, improvement of clinical symptoms, respiratory mechanics parameters related to lung function, and blood gas analysis indexes were compared between the two groups, and safety was evaluated. The frequency of apnea at 48 h and 72 h was significantly lower in the high-dose group than in the low-dose group, and the difference was statistically significant (P < 0.05). The time to resolution of apnea, the time to mechanical ventilation, and the time to citrate use were significantly shorter in the high-dose group than in the low-dose group (P < 0.05). The tidal volume and peak expiratory flow values were significantly higher in the high-dose group than in the low-dose group (P < 0.05). The oxygen partial pressure and pulse oximetry levels in the blood gas analysis indexes of the high-dose group were significantly higher than those of the low-dose group, and the partial pressure of carbon dioxide level was significantly lower than that of the low-dose group, with statistically significant differences (P < 0.05). The safety evaluation results showed no significant difference in the rate of adverse reactions and short-term complications between the high-dose group and the low-dose group (P > 0.05). Caffeine citrate at a maintenance dose of 10 mg/kg can effectively reduce the frequency of apnea, shorten the improvement time of clinical symptoms, and improve the lung function and blood gas analysis level of children with a high safety profile.

Partial pressure of carbon dioxide levels reflect disease severity in idiopathic pleuroparenchymal fibroelastosis

BackgroundHypercapnia can cause a disturbance of consciousness and adversely affect a patient's general condition. Patients with interstitial lung disease seldom experience hypercapnia. Hypercapnia is a typical phenomenon in patients with pleuroparenchymal fibroelastosis (PPFE), especially in advanced stages. However, the clinical significance of hypercapnia in patients with idiopathic PPFE (iPPFE) has not been studied in detail. MethodsWe retrospectively selected patients with iPPFE who had undergone blood gas analysis. The first blood gas data obtained after iPPFE diagnosis were examined. The partial pressure of carbon dioxide (PCO2) levels and their association with characteristic iPPFE parameters, including the flat chest index (the ratio of the anteroposterior diameter of the thoracic cage to the transverse diameter of the thoracic cage), were investigated. ResultsA total of 47 patients with iPPFE were included in this study. The PCO2 level was moderately and inversely correlated with the forced vital capacity. (r = −0.431, P = 0.014), flat chest index (r = −0.497, P < 0.001), and body mass index (r = −0.313, P = 0.038) and was positively correlated with residual volume/total lung capacity. (r = 0.514, P < 0.01). A higher PCO2 level was also significantly associated with poorer prognosis in patients with iPPFE. ConclusionsPCO2 levels could be used as an indicator of disease severity in patients with iPPFE.

Use of Non-Invasive Ventilation in Reducing Partial Pressure of Carbon Dioxide Level (PaCO2) in Neonates with Respiratory Distress Syndrome

Objective: It has been observed that non-invasive ventilation used in premature with Respiratory distress syndrome and notably decrease level of partial pressure of carbon-dioxide (PaCO2) level in blood. The primary goal of this study was to assess the effect of non-invasive ventilation in decreasing the level of partial pressure of carbon dioxide (PaCO2) level and supplementary oxygen need in premature neonates with RDS. Study Design and Settings: This randomized controlled trial was done in Jan 2021 till August 2021 at PNS SHIFA Karachi. Methodology: Neonates with gestational age (GA &lt;34 wk) with RDS at birth were randomly assigned to nasal intermittent positive pressure ventilation (NIPPV) and nasal high frequency oscillatory ventilation (NHFOV) for respiratory support after giving surfactant .Twenty three preterm babies were included in each group .Level of partial pressure of carbon dioxide at 2hrs and 24hrs of non-invasive ventilation and supplementary oxygen need was evaluated. Results: Non-invasive ventilation was found to reduce the PaCO2 level (p= .01), NIPPV (43.06±13.74) vs. (33.63±19.99) in NHFOV at 2hrs and 24hrs NIPPV (19.89±7.18) vs. NHFOV (14.04±8.39).Value of pH was also significant in two groups with optimal mean airway pressure. Supplementary oxygen period were also reduced in NHFOV than NIPPV group (35.7% vs. 64.3%). Conclusion: NHFOV was a beneficial mode in maintaining level of pH, PaCO2 level and reducing need of supplementary oxygen in preterm babies with RDS

Risk factors associated with postoperative respiratory failure in tuberculous empyema patients.

Our objective was to identify independent risk factors for predicting which patients in the Chinese population would likely develop respiratory failure.A descriptive analysis was conducted of demographic and clinical data of patients with tuberculous empyema (TE) admitted to the Beijing Chest Hospital, Capital Medical University between January 2001 and January 2020. Risk factors associated with postsurgical respiratory failure in TE patients were identified based on results of analyses based on univariable and multivariable logistic regression models.A total of 139 TE patients who underwent surgical treatment in the Beijing Chest Hospital, Capital Medical University from January 2001 to January 2020 were enrolled in this study. Cases included 109 male and 30 female patients, with an overall mean age (range 17–73) of 39.3 years. Of 139 TE patients, 26 (18.7%) experienced respiratory failure after surgery. Among significant risk factors for postsurgical respiratory failure, intraoperative blood loss volume greater than 1000 mL had the highest odds ratio value of 6.452. In addition, a pathologic preoperative pulmonary function test result showing a high partial pressure of carbon dioxide level was an independent risk factor for respiratory failure. Moreover, the presence of tuberculosis lesions in the contralateral lung was another significant risk factor for respiratory failure, as determined using multivariate analysis.Respiratory failure is a predominant complication experienced by TE patients undergoing surgery. High intraoperative blood loss, high preoperative high partial pressure of carbon dioxide level, and tuberculosis lesion(s) in the contralateral lung of TE patients were associated with increased risk of postoperative respiratory failure.

Nonintubated video-assisted thoracic surgery with high-flow oxygen therapy shorten hospital stay.

Background:Nonintubated video-assisted thoracic surgery (VATS) is widely used due to its acceptable postoperative outcomes. Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) has been successfully applied in cases of prolonged difficult intubation and intensive respiratory care in patients receiving VATS lobectomy. Thopaz Digital Chest Drainage System (THOPAZ) provides regulated negative pressure close to the patient’s chest, optimizing drainage of the pleural and mediastinum. We explored the surgical outcomes of nonintubated VATS lung wedge resection and traditional wedge resection with a double-lumen endotracheal tube.Methods:Patients who received nonintubated VATS lung wedge resection (group A, n = 81) and traditional wedge resection with double-lumen endotracheal tube (group B, n = 79) during the period of November 2015 to April 2018 were enrolled in the study. Demographic data and operation outcomes were obtained and analyzed from review of patient medical charts.Results:Group B had significantly longer mean induction and operative times than group A. Similarly, group B suffered greater intraoperative blood loss, longer postoperative hospital stays, and increased chest tube retention times than group A. Group A had higher partial pressure of carbon dioxide levels in both the pre-one-lung and during one-lung ventilation periods than group B. Furthermore, group A showed lower serum pH levels during one-lung ventilation period. However; group A had significantly higher partial pressure of oxygen levels during one-lung ventilation than group B, although the differences in peripheral oxygen saturation were not statistically significant.Conclusion:Our study demonstrated that nonintubated VATS using THRIVE and THOPAZ in lung wedge resection provides measurable benefits to patients.

Metabolic profile and outcome of pre- and post-ampullary gastrointestinal obstruction in children: Conventional or unconventional wisdom.

Background:Conventionally, it is well accepted that the intestinal obstructions in children, especially gastric outlet obstruction are associated with significant metabolic derangement which has impact on its outcome. The study aimed to compare the metabolic profile and treatment outcome of pre- and post-ampullary gastrointestinal obstruction in children at a tertiary care setting.Materials and Methods:A prospective observational study was conducted on 30 children with intestinal obstruction and categorised into Group 1 (pre-ampullary, n = 11) and Group 2 (post-ampullary, n = 19) as per their anatomical site of pathology. Patients were evaluated at both pre- and post-operative period (Day 1 and 10) with haematological, biochemical and blood gas. The pre- and post-operative metabolic profile, resuscitative time and outcome were compared in two groups.Results:Except mild leucocytosis (Group II > I), rest of the pre-operative and post-operative haematological parameters were within normal range and statistically comparable among groups. Although the pre-operative sodium values were within the normal limit in both groups, it was relatively higher in Group I (Group I = 137.82 ± 4.238 vs. Group II = 134.26 ± 4.653), (P = 0.04). The mean bicarbonate values were within the normal limit in both groups (22.49 and 19.34), but the difference was statistically significant (P = 0.031). Mean partial pressure of carbon dioxide level was higher than normal range in Group I (38.464 ± 20.6493) but was comparable with Group II (P = 0.15). The time required for pre-operative resuscitation was 16.6 versus 24.87 h in Group I versus Group II (P = 0.02). In Group I, all children were improved, whereas four children expired in Group II.Conclusion:Metabolic profile in both pre- and post-ampullary intestinal obstruction was found to be normal in majority of the scenario. Children with post-ampullary obstruction need extensive pre-operative resuscitation and have relatively poor outcome.

Evaluation of pain scoring and free cortisol levels of postoperative analgesic methods in cardiac surgery: A new perspective.

This study aims to evaluate the most appropriate analgesic method of minimizing postoperative pain to prevent complications in patients scheduled for cardiac surgery. Between January 2016 and June 2016, a total of 60 patients with the American Society of Anesthesiologists Physical Status Class III (27 males, 33 females; mean age 63 years; range, 49 to 77 years) with an ejection fraction of above 50% who underwent elective coronary artery bypass grafting were included. The patients were divided into two groups following admission to the intensive care unit. Group 1 (n=30) was administered intravenous fentanyl citrate with patient-controlled analgesia protocol, while Group 2 (n=30) was administered 0.1% bupivacaine hydrochloride analgesia protocol with catheter placed between the sternum and subcutaneous tissue. In Group 1, pain intensity scores at two h and visual analog scale scores except at 24, 36, and 48 h were higher than Group 2 (p<0.05). The length of intensive care unit stay and urine cortisol levels were higher in Group 1 than Group 2 (78±12 h and 631±505 ?g at 24 h vs. 66±13 h and 401±297 ?g at 24 h, respectively p<0.05). Partial pressure of oxygen levels at 10 and 16 h during the postoperative intensive care unit stay were lower, while partial pressure of carbon dioxide levels at 24 h was higher in Group 1 than Group 2 (p<0.05). The bupivacaine protocol is a relatively more useful analgesic method which produces improved results in blood gas analysis by reducing the effects of pain and shortens the length of intensive care unit stay. Low levels of free cortisol also confirm this finding.

Pediyatrik Kalp Cerrahisinde Transkutanöz ve İntraarteriyel Kan Gazı Monitörizasyonun Karşılaştırılması

Objective: We compared transcutaneous and intra-arterial blood gas measurements following pediatric cardiac surgery in this study. Material and Methods: A total of 150 pediatric patients who underwent surgery for congenital cardiac disease between June 2014 and November 2015 were included in the study. The efficacy of a transcutaneous non-invasive device in measuring oxygen and carbon dioxide pressures was evaluated in pediatric patients who underwent cardiovascular surgery for congenital diseases. Simultaneous transcutaneous and conventional arterial blood gases, as well as partial oxygen and carbon dioxide pressure levels were measured in 150 pediatric patients. Results: The mean age and weight of the patients were 3.7±3.1 years (range, 1 month to 16 years) and 11.7±15.1 kg (range 3.5 to 55 kg), respectively. The differences in the mean partial oxygen and carbon dioxide pressure levels were 8 mmHg (range, 3 to 20 mmHg) and 12 mmHg (range, 7 to 25 mmHg), respectively (p 0.05). This was due to the fact that transcutaneous measurements dependent on skin perfusion yielded more accurate and reliable results in optimal conditions, such as a relatively normal cardiovascular function. Conclusion: Although transcutaneous measurements were less accurate than the invasive method in the present study, its use in intensive care units where optimal conditions are provided could decrease the number of invasive arterial interventions and contact with blood, while also allowing continuous monitoring and the evaluation of ventilation efficacy.

Venous lactate, pH and partial pressure of carbon dioxide levels as prognostic indicators in 110 premature calves with respiratory distress syndrome

Hyperlactatemia, hypercapnia, low pH and low oxygen saturation (SatO2) are commonly observed in premature calves. These clinical indicators are associated with increased mortality in preterm human newborns with respiratory distress...

The accuracy of mainstream end-tidal carbon dioxide levels to predict the severity of chronic obstructive pulmonary disease exacerbations presented to the ED

IntroductionThe end-tidal carbon dioxide (ETCO2) measurement was considered as an essential tool for the assessment of several conditions in emergency medicine. However, the diagnostic role of capnography in dyspneic patients still remains unclear. We aimed to analyze the alteration of the ETCO2 levels in chronic obstructive pulmonary disease (COPD) exacerbations and its role in the decision-making process. MethodsAll the individuals who were presented to the emergency department (ED) after COPD exacerbations were prospectively enrolled in the study. The patients were excluded if they refused to give informed consent, intubated after initial assessment, and had uncertain COPD diagnosis. The ETCO2 measurement using a mainstream capnometer was undertaken in the pretreatment and post-treatment period of COPD exacerbations. ResultsA total of 102 patients were enrolled in the study. Pre-ETCO2 and post-ETCO2 levels were positively correlated with arterial partial carbon dioxide pressure levels (r=0.756, P<.001 and r=0.629, P<.001, respectively). The median pre-ETCO2 level was 32.0 (30.5-40.5) in discharged patients and 39.0 (31.0-53.5) in admitted patients. After the initial therapy in the ED was completed, the median post-ETCO2 level was found to be 32.0 (28.0-37.5) in discharged patients and 36.0 (32.0-52.0) in admitted patients. Although a statistically significant difference was observed in the pretreatment period (P=.043), no difference was observed in post-treatment period between ETCO2 levels (P=.107). ConclusionEnd-tidal carbon dioxide levels were higher in admitted patients when compared with discharged patients on arrival to the ED. ETCO2 measurement has very little contributions while evaluating patients with COPD exacerbation in the ED.

Clinical and hemodynamic features of Eisenmenger syndrome patients at the time of first admission: a tertiary referral-center experience

In this study, patients admitted with the diagnosis of Eisenmenger syndrome (ES) in a tertiary referral center were analyzed. The data of 20 consecutive patients (mean age: 27.6+1.8 years, 7 male and mean follow-up time: 35.6 ± 9.1 months) with ES were retrospectively analyzed. Demographic characteristics, symptoms, physical examination, laboratory and hemodynamic parameters were analyzed at the time of first admission. The most frequent underlying heart diseases were ventricular septal defect (VSD) with complex congenital disease (n:8, 40%) and isolated VSD (n:7, 35%). 6-minute walking test distance was 347.9 ± 33.7 meters and 15 patients (75%) had a functional capacity of NYHA Class III, at the time of admission. ES was diagnosed with catheterization in all patients and mean systolic pulmonary arterial pressure measured by catheterization was 112 ± 6.8 mmHg. Pulmonary function tests, FVC (forced vital capacity), FEV1 (forced expiratory volume), FEV1/FVC values were respectively, 3.1 ± 0.4, 2.5 ± 0.4 L and 76.7 ± 3.3%. Metabolic tests were performed in all patients at the first visit. Mean VO2 max was 16.7 ± 1.0 ml / kg/min and VE/VCO2 rate was 53.9 ± 3.2%. Although PH and partial pressure of carbon dioxide levels were within normal range in blood gas analysis, oxygen saturation and partial pressure of oxygen levels were low. The most common underlying heart disease of ES patients is VSD. In this cases exercise capacity is restricted and this restriction is reflected in laboratory parameters.

Accuracy and reliability of pulse oximetry at different arterial carbon dioxide pressure levels

The present study aimed to assess whether arterial carbon dioxide pressure (Pa,CO(2)) has an impact on agreement between oxygen saturation measured with pulse oximetry (Sp,O(2)) or arterial blood gas co-oximetry (Sa,O(2)). Sa,O(2) and Sp,O(2) determinations were obtained simultaneously from 846 patients under assessment for long-term home oxygen therapy in a specialised outpatient clinic. Both measurements were taken with patients seated and breathing room air. Agreement between Sa,O(2) and Sp,O(2) results was analysed by the Bland-Altman method and the Lin concordance coefficient. In addition, potential interactions of arterial oxygen tension (Pa,O(2)) or Pa,CO(2) on agreement were analysed by adjusted multivariate analysis. Upon comparison of Sa,O(2) and Sp,O(2) results, the Bland-Altman technique yielded a bias (95% confidence interval (CI)) of -1.24 (-6.86-4.38) and -1.32 (-7.78-5.15) when Pa,CO(2) >48 mmHg (6.39 kPa) or Pa,O(2) <54 mmHg (7.20 kPa), respectively. Estimate by Lin's coefficient (95% CI) in these cases was 0.88 (0.85-0.90) and 0.81 (0.77-0.85). Adjusted multivariate analysis, performed to assess the impact of pH, Pa,O(2), Pa,CO(2) and bicarbonate on bias, showed that Pa,O(2), Pa,CO(2) and their interaction terms were the most important predictors of the bias (standardised estimates of -0.54, -0.94, and 0.85, respectively). The effect of pH, although statistically significant, was small, and bicarbonate had no significant effect. Arterial carbon dioxide pressure status can contribute to impaired agreement between arterial oxygen saturation and arterial oxygen saturation measured with pulse oximetry, particularly in patients with hypercapnia.

Comparison of double-lung jet ventilation and one-lung ventilation for thoracotomy

Thoracic surgery requires immobilization of the operating area. Usually, this is achieved with one-lung ventilation (OLV), however this may still lead to some movement. High-frequency jet ventilation (HFJV) may be an alternative way of ventilation in thoracic surgery. The purpose of this study was to determine the effectiveness of HFJV as an alternative option to OLV for thoracic procedures. Sixty patients were randomized to receive either HFJV (n = 29) or OLV (n = 31) during the operation. During the course of the study 10 patients were excluded (4 patients in HFJV group and 6 patients in OLV group). The following haemodynamic and ventilatory parameters were recorded: heart rate, systolic and mean blood pressure, ventricular stroke volume, cardiac index, systemic vascular resistance, peak inspiratory pressure, oxygen saturation, PaO2 and PaCO2. Overall parameters were documented before the initiation of the chosen mode of ventilation every 15 min during the operation. Patients in both groups showed comparable cardiovascular function. Mean values of peak inspiratory pressure were significantly higher in the OLV group. Oxygen saturation values were statistically higher in the HFJV group. PaCO2 values were similar in both during surgery, but were higher in the OLV group after awakening. Mean values of shunt fraction were lower in the HFJV group. Lower values of peak inspiratory pressure were therefore associated with higher partial pressure of carbon dioxide levels in the HFJV group. In the OLV group, 44% of patients experienced a postoperative sore throat. Operating conditions were comparable. HFJV is safe option, comparable to OLV and offers some advantages for open-chest thoracic procedures.

High-frequency percussive ventilation: an alternative mode of ventilation for head-injured patients with adult respiratory distress syndrome.

Adult respiratory distress syndrome develops in up to 20% of patients with severe head injury. This complicates the treatment of head-injured patients because lung-protective strategies such as high positive end-expiratory pressure (PEEP) and permissive hypercapnia may increase intracranial pressure (ICP) and reduce cerebral perfusion pressure. The use of high-frequency percussive ventilation (HFPV) is an alternate mode of ventilation that may improve oxygenation for head-injured patients while also lowering ICP. Clinical data were collected retrospectively over a 1-year period. Patients were included if they had a severe traumatic brain injury with a Glasgow Coma Score (GCS) of 8 or lower, a ventriculostomy drain for ICP measurement and cerebral spinal fluid drainage, and adult respiratory distress syndrome. Patients were switched from conventional mechanical ventilation to HFPV at the discretion of the attending trauma surgeon. Data for partial pressure of oxygen to fraction of inspired oxygen (PF) ratio, peak inspiratory pressure (PIP), ICP, partial pressure of carbon dioxide level (PCO2), PEEP, and mean airway pressure were compared before and then 4 and 16 hours after institution of HFPV therapy. A total of 10 patients met study criteria. Data were expressed as mean +/- standard error. There was an increase in PF ratio (91.8 +/- 13.2 vs. 269.7 +/- 34.6; p < 0.01), PEEP (14 +/- 2.5 vs. 16 +/- 3.5), and mean airway pressure (20.4 +/- 4.8 vs. 23.6 +/- 6.8) 16 hours after institution of HFPV. There was a decrease in ICP (30.9 +/- 3.4 vs. 17.4 +/- 1.7; p < 0.01), PC02 (37.7 +/- 4.1 vs. 32.7 +/- 1.1; p < 0.05), and PIP (49.4 +/- 10 vs. 41 +/- 7.9; p < 0.05) at 16 hours. Overall mortality was 10%. Therapy with HFPV produced a significant improvement in oxygenation with a concomitant reduction in ICP during the first 16 hours. This therapy may represent an important new method for the management of adult respiratory distress syndrome among head-injured trauma patients, although the long-term outcome of HFPV still needs evaluation.

Transdiaphragmatic Pressure Control of Airway Pressure Support in Healthy Subjects

We designed a new servoventilator that proportionally adjusts airway pressure to transdiaphragmatic pressure (Pdi) generated by the subject during inspiration. Each cycle is triggered by either a preset Pdi increase or a preset inspiratory flow value (whichever is reached first), whereas cycling-off is flow-dependent. We evaluated the servoventilator in seven healthy subjects at normocapnia and three levels of hypercapnia (normocapnia + 3, + 6, and + 9 mm Hg) comparatively with spontaneous breathing. Triggering was by Pdi in six subjects and flow in one. At all end-tidal carbon dioxide pressure levels, time from onset of diaphragm electromyographic activity to inspiratory flow was similar with and without the servoventilator. Airway pressure increased proportionally to Pdi variation during servoventilator breathing. Flow, tidal volume, respiratory rate, intrinsic positive end-expiratory pressure, and esophageal and transdiaphragmatic pressure-time products increased significantly with hypercapnia with and without the servoventilator. Breathing pattern parameters were similar in the two breathing modes, and no differences were found for intrinsic positive end-expiratory pressure or gastric pressure variation during exhalation. Esophageal and transdiaphragmatic pressure-time products were lower with than without the servoventilator. The Pdi-driven servoventilator was well synchronized to the subjects effort, delivering a pressure proportional to Pdi and reducing respiratory effort at normocapnia and hypercapnia.

Leptin as an acute stress-related hormone in the fetoplacental circulation

OBJECTIVE:To investigate the relationship between fetoplacental leptin secretion and blood gases.METHODS:We measured the levels of umbilical arterial and venous leptin, umbilical cord gas, umbilical venous blood glucose, and estradiol-17β (E2) in 89 pregnant women. Correlation between the leptin levels and other variables (gestational age, birth weight, maternal body weight, height, body mass index, maternal body weight gain, placental weight, umbilical cord gas data, and levels of umbilical venous blood glucose and E2) were examined statistically.RESULTS:Umbilical arterial and venous leptin levels were 7.64 ± 12.76 and 7.76 ± 13.17 (ng/mL), respectively, correlating positively with carbon dioxide pressure levels (r = 0.446, P < .001; r = 0.406, P < .001, respectively) and correlating inversely with pH (r = −0.337, P = .001; r = −0.247, P = .019, respectively). Umbilical venous glucose, E2, and other factors did not correlate with leptin levels.CONCLUSION:Leptin secretion into the fetoplacental circulation may be associated with fetal hypercapnia, suggesting two important roles for leptin: one for basal control of fetal fat tissue and one as an acute stress-related hormone.

Leptin as an Acute Stress-Related Hormone in the Fetoplacental Circulation

In Brief OBJECTIVE To investigate the relationship between fetoplacental leptin secretion and blood gases. METHODS We measured the levels of umbilical arterial and venous leptin, umbilical cord gas, umbilical venous blood glucose, and estradiol-17β (E2) in 89 pregnant women. Correlation between the leptin levels and other variables (gestational age, birth weight, maternal body weight, height, body mass index, maternal body weight gain, placental weight, umbilical cord gas data, and levels of umbilical venous blood glucose and E2) were examined statistically. RESULTS Umbilical arterial and venous leptin levels were 7.64 ± 12.76 and 7.76 ± 13.17 (ng/mL), respectively, correlating positively with carbon dioxide pressure levels (r = 0.446, P < .001; r = 0.406, P < .001, respectively) and correlating inversely with pH (r = −0.337, P = .001; r = −0.247, P = .019, respectively). Umbilical venous glucose, E2, and other factors did not correlate with leptin levels. CONCLUSION Leptin secretion into the fetoplacental circulation may be associated with fetal hypercapnia, suggesting two important roles for leptin: one for basal control of fetal fat tissue and one as an acute stress-related hormone. Leptin may be an acute stress-related hormone.

Effect of graded hemorrhage on renal cortical perfusion in dogs

Renal cortical tissue gas tensions, systemic oxygen supply and some features of energy metabolism and central hemodynamics were recorded in splenectomized dogs during graded hemorrhage and subsequent reinfusion of shed blood. Renal cortical partial pressure of oxygen and carbon dioxide responded rapidly to changes in blood volume and cardiac output. Lowest cortical partial pressure of oxygen values and highest cortical partial pressure of carbon dioxide levels were achieved at a maximal 50 percent blood loss. The decrease in arterial pressure, blood hemoglobin and hematocrit as well as the increase in blood lactate concentration lagged behind blood loss. Renal cortical partial pressure of oxygen, arterial pressure and cardiac output responded rapidly to reinfusions of withdrawn blood, while the cortical partial pressure of carbon dioxide, heart rate, arterial pH and blood lactate concentration returned to initial levels more slowly. Arterial blood gases remained normal throughout the observation period and did not provide an adequate index of tissue oxygenation. In contrast, the partial pressure of oxygen of the renal cortex proved an excellent and sensitive indicator of renal perfusion during hemorrhagic shock and its management.