Home About us Contact
|
Home About us Contact | ||
|
|
||
Arterial Oxygenation (arterial + oxygenation)
Selected AbstractsDynamic pharyngeal collapse in racehorsesEQUINE VETERINARY JOURNAL, Issue S36 2006A. G. BOYLE Summary Reason for performing study: Dynamic pharyngeal collapse (PC) is a condition seen in racehorses that can be career-ending. Objectives: To characterise and grade PC and describe the effects of PC on athletic performance. Methods: Medical records were reviewed for 828 horses, of which 49 (6%) records were identified as horses with a primary diagnosis of PC. Tapes of video-endoscopy of the pharynx during exercise were reviewed. Each video recording was assigned a grade (0,4) reflecting the degree of PC and a classification for severity of upper airway obstruction. Earnings per race prior to diagnosis of PC were compared to earnings per race after diagnosis of PC for all horses, as well as performance index (PI). Available exercising arterial blood gases were reviewed for horses with PC. Results: There were 35 (80%) Thoroughbreds (TB), and 9 (20%) Standardbreds (STD). 32 (73%) had a history of making an upper respiratory noise. 4 (9%) grade 1 PC, 8 (18%) grade 2 PC, 26 (59%) grade 3 PC, and 6 (14%) grade 4 PC. Seven (16%) horses were classified as mild PC, 18 (41%) as low-moderate PC, 14 (32%) as high-moderate PC, and 5 (11%) as severe PC. Of 30 horses 11 had abnormally decreased PaO2 and 8 horses had abnormally elevated PaCO2. A significant decrease was found in earnings per race prediagnosis when compared to post diagnosis earnings per race in horses ?4 years of age (P = 0.003). A significant decrease was also observed for earnings per race prediagnosis when compared to post diagnosis earnings per race in horses with grade 3 PC (P = 0.03) No significant differences were observed in PI before or after diagnosis of PC. Conclusions: There was a trend for PC to be observed in more TB than STD, and more males than females compared to the general hospital population. Horses with PC significant had decreases in arterial oxygenation. Racing records after a diagnosis of PC in all horses ?4 years of age suggesting that older horses have a guarded prognosis for continued success. Potential relevance: This study provides a classification system for dynamic pharyngeal collapse and suggests that older racehorses (?4 years of age) diagnosed with PC and all horses with grade 3 PC have a poor prognosis for return to previous level of performance. [source] Iron chelation prevents lung injury after major hepatectomyHEPATOLOGY RESEARCH, Issue 8 2010Konstantinos Kalimeris Aim:, Oxidative stress has been implicated in lung injury following ischemia/reperfusion and resection of the liver. We tested whether alleviating oxidative stress with iron chelation could improve lung injury after extended hepatectomy. Methods:, Twelve adult female pigs subjected to liver ischemia for 150 min, 65,70% hepatectomy and reperfusion of the remnant liver for 24 h were randomized to a desferrioxamine (DF) group (n = 6) which received i.v. desferrioxamine to a total dose of 100 mg/kg during both ischemia and reperfusion, and a control (C) group (n = 6). We recorded hemodynamic and respiratory parameters, plasma interleukin-6 and malondialdehyde levels, as well as liver malondialdehyde and protein carbonyls content. Total non-heme iron was measured in lung and liver. Pulmonary tissue was evaluated histologically for its nitrotyrosine and protein carbonyls content and for superoxide dismutase (SOD) and platelet-activating factor acetylhydrolase (PAF-AcH) activities. Results:, Reperfusion of the remnant liver resulted in gradual deterioration of gas-exchange and pulmonary vascular abnormalities. Iron chelation significantly decreased the oxidative markers in plasma, liver and the lung and lowered activities of pulmonary SOD and PAF-AcH. The improved liver function was followed by improved arterial oxygenation and pulmonary vascular resistance. DF also improved alveolar collapse and inflammatory cell infiltration, while serum interleukin-6 increased. Conclusion:, In an experimental pig model that combines liver resection with prolonged ischemia, iron chelation during reperfusion of the remnant liver is associated with improvement of several parameters of oxidative stress, lung injury and arterial oxygenation. [source] Gravity is an important determinant of oxygenation during one-lung ventilationACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 6 2010L. L. SZEGEDI Background: The role of gravity in the redistribution of pulmonary blood flow during one-lung ventilation (OLV) has been questioned recently. To address this controversial but clinically important issue, we used an experimental approach that allowed us to differentiate the effects of gravity from the effects of hypoxic pulmonary vasoconstriction (HPV) on arterial oxygenation during OLV in patients scheduled for thoracic surgery. Methods: Forty patients with chronic obstructive pulmonary disease scheduled for right lung tumour resection were randomized to undergo dependent (left) one-lung ventilation (D-OLV; n=20) or non-dependent (right) one-lung ventilation (ND-OLV; n=20) in the supine and left lateral positions. Partial pressure of arterial oxygen (PaO2) was measured as a surrogate for ventilation/perfusion matching. Patients were studied before surgery under closed chest conditions. Results: When compared with bilateral lung ventilation, both D-OLV and ND-OLV caused a significant and equal decrease in PaO2 in the supine position. However, D-OLV in the lateral position was associated with a higher PaO2 as compared with the supine position [274.2 (77.6) vs. 181.9 (68.3) mmHg, P<0.01, analysis of variance (ANOVA)]. In contrast, in patients undergoing ND-OLV, PaO2 was always lower in the lateral as compared with the supine position [105.3 (63.2) vs. 187 (63.1) mmHg, P<0.01, ANOVA]. Conclusion: The relative position of the ventilated vs. the non-ventilated lung markedly affects arterial oxygenation during OLV. These data suggest that gravity affects ventilation,perfusion matching independent of HPV. [source] Measurements of functional residual capacity during intensive care treatment: the technical aspects and its possible clinical applicationsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2009H. HEINZE Direct measurement of lung volume, i.e. functional residual capacity (FRC) has been recommended for monitoring during mechanical ventilation. Mostly due to technical reasons, FRC measurements have not become a routine monitoring tool, but promising techniques have been presented. We performed a literature search of studies with the key words ,functional residual capacity' or ,end expiratory lung volume' and summarize the physiology and patho-physiology of FRC measurements in ventilated patients, describe the existing techniques for bedside measurement, and provide an overview of the clinical questions that can be addressed using an FRC assessment. The wash-in or wash-out of a tracer gas in a multiple breath maneuver seems to be best applicable at bedside, and promising techniques for nitrogen or oxygen wash-in/wash-out with reasonable accuracy and repeatability have been presented. Studies in ventilated patients demonstrate that FRC can easily be measured at bedside during various clinical settings, including positive end-expiratory pressure optimization, endotracheal suctioning, prone position, and the weaning from mechanical ventilation. Alveolar derecruitment can easily be monitored and improvements of FRC without changes of the ventilatory setting could indicate alveolar recruitment. FRC seems to be insensitive to over-inflation of already inflated alveoli. Growing evidence suggests that FRC measurements, in combination with other parameters such as arterial oxygenation and respiratory compliance, could provide important information on the pulmonary situation in critically ill patients. Further studies are needed to define the exact role of FRC in monitoring and perhaps guiding mechanical ventilation. [source] Iloprost inhalation redistributes pulmonary perfusion and decreases arterial oxygenation in healthy volunteersACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2009D. RIMEIKA Background: Previous studies have shown that ventilation,perfusion matching is improved in the prone as compared with that in the supine position. Regional differences in the regulation of vascular tone may explain this. We have recently demonstrated higher production of nitric oxide in dorsal compared with ventral human lung tissue. The purpose of the present study was to investigate regional differences in actions by another vasoactive mediator, namely prostacyclin. The effects on gas exchange and regional pulmonary perfusion in different body positions were investigated at increased prostacyclin levels by inhalation of a synthetic prostacyclin analogue and decreased prostacyclin levels by unselective cyclooxygenase (COX) inhibition. Methods: In 19 volunteers, regional pulmonary perfusion in the prone and supine position was assessed by single photon emission computed tomography using 99mTc macro-aggregated albumin before and after inhalation of iloprost, a stable prostacyclin analogue, or an intravenous infusion of a non-selective COX inhibitor, diclofenac. In addition, gas distribution was assessed in seven subjects using 99mTc-labelled ultra-fine carbon particles before and after iloprost inhalation in the supine position. Results: Iloprost inhalation decreased arterial PaO2 in both prone (from 14.2±0.5 to 11.7±1.7 kPa, P<0.01) and supine (from 13.7±1.4 to 10.9±2.1 kPa, P<0.01) positions. Iloprost inhalation redistributed lung perfusion from non-dependent to dependent lung regions in both prone and supine positions, while ventilation in the supine position was distributed in the opposite direction. No significant effects of non-selective COX inhibition were found in this study. Conclusions: Iloprost inhalation decreases arterial oxygenation and results in a more gravity-dependent pulmonary perfusion in both supine and prone positions in healthy humans. [source] The effects of activated protein C and prostacyclin on arterial oxygenation and protein leakage in the lung and the gut under endotoxaemia in the ratACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2008M. DUBNIKS Background: Based on the anti-adhesive/anti-aggregatory and permeability-reducing properties of activated protein C (APC) and prostacyclin (PGI2), we analysed and compared these substances regarding their efficacy in counteracting transcapillary leakage of albumin in the lung and the gut, and in improving arterial oxygenation under a condition of inflammation. Methods: The randomized and blinded study was performed on 31 adult male Sprague-Dawley rats. Inflammation was induced by continuous infusion of Escherichia coli endotoxin (lipopolysaccharide, LPS). Six hours after the start of the LPS infusion (240,000 U/kg/h), a simultaneous infusion of saline (control group) or 8 ,g/kg/min of human recombinant APC or 2 ng/kg/min of PGI2 was started and continued for 24 h (n=8 per group). The study also included a sham group. Transcapillary leakage of albumin was measured from the ratio between tissue radioactivity [counts per minute (cpm)/g tissue] and actual amount of radioactivity given (cpm/g body weight of 125I-albumin). Oxygenation was assessed from arterial and central venous blood samples. Results: LPS induced albumin leakage in the gut and the lung, and impaired blood oxygenation. In the lung, the leakage was lower in the PGI2 group than in the APC and the control groups (P<0.05). In the gut, it was lower in the APC and the PGI2 groups than in the control group (P<0.05). Oxygenation was better in the APC and PGI2 groups than in the control group. Conclusion: Our data suggest that both APC and low-dose PGI2 are beneficial in LPS-induced inflammation in the rat, by reducing albumin leakage and improving blood oxygenation. [source] Cardiovascular and Pulmonary Effects of Hetastarch Plus Hypertonic Saline Solutions during Experimental Endotoxemia in Anesthetized HorsesJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 6 2006DACVIM, Lucas G. Pantaleon MV Background:Small volume resuscitation has been advocated as a beneficial therapy for endotoxemia in horses but this therapy has not been investigated in a prospective manner. The objective of this study was to determine the cardiopulmonary effects of small-volume resuscitation using hypertonic saline solution (HSS) plus Hetastarch (HES) during experimental endotoxemia in anesthetized horses. Hypothesis:Treatment of horses with induced endotoxemia using HES-HSS does not alter the response of various cardiopulmonary indices when compared to treatment with either small-or large-volume isotonic crystalloid solutions. Animals:Eighteen healthy horses were randomly assigned to 1 of 3 groups. Anesthesia was maintained with halothane. Endotoxemia was induced by administering 50 ,g/kg of Escherichia coli endotoxin IV. The horses were treated over 30 minutes with 15 mL/kg of balanced polyionic crystalloid solution (control), 60 mL/kg of balanced polyionic crystalloid solution (ISO), or 5 mL/kg of HSS followed by 10 mL/kg of HES (HSS-HES). Methods:Prospective randomized trial. Results:Cardiac output (CO) after endotoxin infusion increased significantly (P < .05) from baseline in all groups, whereas mean central venous pressure increased significantly (P < .05) in the ISO group only. Mean pulmonary artery pressure increased from baseline (P < .05) in horses treated with isotonic fluids and HSS-HES. There was no effect of treatment with HSS-HES on CO, systemic vascular resistance (SVR), mean arterial pressure, blood lactate concentrations, or arterial oxygenation. Conclusions and Clinical Importance: The use of HSS-HES failed to ameliorate the deleterious hemodynamic responses associated with endotoxemia in horses. The clinical value of this treatment in horses with endotoxemia remains unconfirmed. [source] Pilot study of pentoxifylline in hepatopulmonary syndrome,LIVER TRANSPLANTATION, Issue 8 2008Rajasekhar Tanikella Hepatopulmonary syndrome (HPS) results when chronic liver disease or portal hypertension causes intrapulmonary microvascular dilatation with hypoxemia. In experimental HPS, tumor necrosis factor alpha (TNF-,) overproduction contributes to vasodilatation, which is improved by pentoxifylline, a TNF-, inhibitor. The effectiveness of pentoxifylline in humans is unknown. The aim of this open-label, single-arm clinical trial was to assess the efficacy and tolerability of pentoxifylline in patients with cirrhosis and advanced HPS undergoing liver transplantation evaluation. Nine adults with cirrhosis and moderate to severe HPS were enrolled. All patients had an initial 2-week titration to a target dose of pentoxifylline of 400 mg by mouth every 8 hours, which was continued for 6 weeks. Baseline and follow-up arterial blood gases and TNF-, levels were evaluated. Adverse effects and tolerability were assessed. The 9 patients had a mean age of 55 ± 10 years, and 67% were female. The most common causes of cirrhosis were hepatitis C virus and alcohol (55%). The mean Model for End-Stage Liver Disease score was 11 (range, 6-19), and patients had advanced hypoxemia [mean partial pressure of arterial oxygen (PaO2) = 54 ± 12 mm Hg, mean alveolar-arterial oxygen gradient (A-a PaO2) = 57 ± 15 mm Hg]. Of the 9 patients enrolled, follow-up blood gases were done in 7. There was no significant change in PaO2 (P = 0.3) or A-a PaO2 (P = 0.3) with treatment. Pentoxifylline was poorly tolerated. Nausea (100%) and vomiting (56%) were the predominant side effects, and only a single patient was able to complete full-dose therapy. Treatment with pentoxifylline did not improve arterial oxygenation in advanced HPS, and tolerance was limited by gastrointestinal toxicity. Liver Transpl 14:1199,1203, 2008. © 2008 AASLD. [source] Utility of pulse oximetry in the detection of arterial hypoxemia in liver transplant candidatesLIVER TRANSPLANTATION, Issue 4 2002Gary A. Abrams MD Assistant Professor of Medicine Hepatopulmonary syndrome, arterial hypoxemia caused by intrapulmonary vasodilatation, occurs in approximately 10% of patients with cirrhosis. The severity of hypoxemia affects liver transplant candidacy and is associated with increased morbidity and mortality posttransplantation. Screening guidelines for detecting the presence of arterial hypoxemia do not exist. The aim of this study is to investigate the accuracy and utility of pulse oximetry in the detection of hypoxemia (PaO2 < 70 mm Hg) in patients with cirrhosis. Two hundred prospective liver transplant candidates were compared with 94 controls. Arterial oxyhemoglobin saturation was obtained by pulse oximetry (SpO2) and compared with simultaneous arterial blood gas (ABG) oxyhemoglobin values (SaO2; bias = the difference). PaO2, carboxyhemoglobin, methemoglobin, and routine clinical and biochemical parameters were investigated to account for the bias. SpO2 overestimated SaO2 in 98% of patients with cirrhosis (mean bias, 3.37%; range, ,1% to 10%). Forty-four percent of patients with cirrhosis and controls had a bias of 4% or greater. No clinical or biochemical parameters of cirrhosis accounted for the overestimation of pulse oximetry. Twenty-five subjects with cirrhosis were hypoxemic, and an SpO2 of 97% or less showed a sensitivity of 96% and a positive likelihood ratio of 3.9 for detecting hypoxemia. An SpO2 of 94% or less detected all subjects with an arterial PaO2 less than 60 mm Hg. Pulse oximetry significantly overestimates arterial oxygenation, and the inaccuracy is not influenced by liver disease. Nevertheless, pulse oximetry can be a useful screening tool to detect arterial hypoxemia in patients with cirrhosis, but a higher threshold for obtaining an ABG must be used. [source] Management of critically ill children with traumatic brain injuryPEDIATRIC ANESTHESIA, Issue 6 2008GILLES A. ORLIAGUET MD PhD Summary The management of critically ill children with traumatic brain injury (TBI) requires a precise assessment of the brain lesions but also of potentially associated extra-cranial injuries. Children with severe TBI should be treated in a pediatric trauma center, if possible. Initial assessment relies mainly upon clinical examination, trans-cranial Doppler ultrasonography and body CT scan. Neurosurgical operations are rarely necessary in these patients, except in the case of a compressive subdural or epidural hematoma. On the other hand, one of the major goals of resuscitation in these children is aimed at protecting against secondary brain insults (SBI). SBI are mainly because of systemic hypotension, hypoxia, hypercarbia, anemia and hyperglycemia. Cerebral perfusion pressure (CPP = mean arterial blood pressure , intracranial pressure: ICP) should be monitored and optimized as soon as possible, taking into account age-related differences in optimal CPP goals. Different general maneuvers must be applied in these patients early during their treatment (control of fever, avoidance of jugular venous outflow obstruction, maintenance of adequate arterial oxygenation, normocarbia, sedation,analgesia and normovolemia). In the case of increased ICP and/or decreased CPP, first-tier ICP-specific treatments may be implemented, including cerebrospinal fluid drainage, if possible, osmotic therapy and moderate hyperventilation. In the case of refractory intracranial hypertension, second-tier therapy (profound hyperventilation with PaCO2 < 35 mmHg, high-dose barbiturates, moderate hypothermia, decompressive craniectomy) may be introduced, after a new cerebral CT scan. [source] Nitric oxide inhalation therapy in very low-birthweight infants with hypoplastic lung due to oligohydramniosPEDIATRICS INTERNATIONAL, Issue 1 2004Naoki Uga AbstractBackground: Although nitric oxide inhalation (iNO) therapy improves arterial oxygenation and reduces the rate of extracorporeal membrane oxygenation in term neonates, the efficacy of this therapy in premature infants is controversial. The objective of the present study was to determine whether iNO therapy improves the survival of very low-birthweight infants with pulmonary hypoplasia due to prolonged rupture of membrane. Methods: A retrospective comparative study of very low-birthweight infants with pulmonary hypoplasia due to oligohydramnios who had or had not been treated with iNO therapy, was performed (iNO-treated group, eight infants; control group, 10 infants). A neonate was considered to have pulmonary hypoplasia due to oligohydramnios if the following conditions were satisfied: (i) artificial surfactant treatment did not improve the respiratory distress; (ii) prolonged rupture of membrane (PROM) continued for more than 5 days with oligohydramnios; and (iii) sufficient arterial oxygenation did not occur even after giving 100% oxygen, and more than 8 cm H2O of mean airway pressure was needed to maintain arterial oxygenation. Results: Nitric oxide inhalation improved arterial oxygenation rapidly and consistently in all eight infants with pulmonary hypoplasia. All eight iNO-treated infants survived longer than 28 days, while five of the 10 control infants died within 24 h of birth (P < 0.05). Before starting iNO, seven of the eight treated infants had shown persistent pulmonary hypertension, which was confirmed by echocardiography. No iNO-treated infant had IVH greater than grade 1, while one control infant had grade 2 IVH. All six long-term survivors in the iNO-treated group are developing normally, while only two of the control infants are developing normally as of February 2002. Conclusions: The majority of the infants with pulmonary hypoplasia due to oligohydramnios had persistent pulmonary hypertension. iNO improved the arterial oxygenation and significantly improved the survival rate. A controlled study to determine whether iNO therapy improves the survival rate of preterm infants with pulmonary hypoplasia due to oligohydramnios is necessary. [source] The relationship between cerebral and somatic oxygenation and superior and inferior vena cava flow, arterial oxygenation and pressure in infants during cardiopulmonary bypass,ANAESTHESIA, Issue 3 2009M. C. White Summary We investigated blood flow and regional oxygenation (rSO2) during cardiopulmonary bypass (CPB). Twenty infants (mean (SD) age 5 (3) months, weight 5.4 (1.6) kg) were prospectively studied. Total CPB and superior vena cava (SVC) flow were measured using Transonic Bypass Flowmeters, inferior vena cava (IVC) flow derived arithmetically and rSO2 measured using Near Infra-Red Spectroscopy. Mean SVC flow was 51.3 (14.8) ml.kg,1.min,1 and mean IVC flow 62.5 (19.0) ml.kg,1.min,1. Mean cerebral rSO2 was 71 (11)% and somatic rSO2 55 (13)%. Cerebral and somatic rSO2 showed no correlation with SVC and IVC flow. Cerebral rSO2 showed a positive correlation with Paco2, mean arterial pressure (MAP) and haematocrit (p < 0.0001). Somatic rSO2 showed a positive correlation with MAP and haematocrit (p = 0.01, p = 0.02). In conclusion, the distribution of blood flow during CPB varies. The most important factor affecting this is Paco2. Cerebral and somatic oxygenation are unaffected by flow but significantly influenced by MAP, haematocrit and Paco2. [source] Combination of Inhaled Nitric Oxide Therapy and Inverse Ratio Ventilation in Patients with Sepsis-Associated Acute Respiratory Distress SyndromeARTIFICIAL ORGANS, Issue 11 2000Kazufumi Okamoto Abstract: Inverse ratio ventilation (IRV) is a ventilatory technique that uses an inspiratory to expiratory ratio (I:E) greater than 1:1. We studied the effects of mechanical ventilation with an I:E of 1:3, 1:1, and 2:1 on arterial oxygenation in 10 patients with sepsis-associated acute respiratory distress syndrome (ARDS). At each I:E, patients received 0 and 4 ppm of inhaled nitric oxide (INO) in random order for 30 min. Respiratory and cardiovascular parameters were measured. Of the 10 patients studied, 7 responded to IRV and 3 did not. An increase in the I:E and the addition of INO significantly improved arterial oxygenation in the responders (p < 0.0001 and p < 0.006, respectively). The combination of an increase in the I:E and INO had an additive effect on arterial oxygenation. The combined use of IRV and INO is a more effective method of avoiding hypoxemia than either INO or IRV alone. [source] | ||||||||||