Biomedical subjects

Ognjen Gajic

Publications and source records attributed to Ognjen Gajic.

At least 19 recordsLinked to original sources

PubMed2006

Failure of non-invasive ventilation in patients with acute lung injury: observational cohort study.

INTRODUCTION: The role of non-invasive positive pressure ventilation (NIPPV) in the treatment of acute lung injury (ALI) is controversial. We sought to assess the outcome of ALI that was initially treated with NIPPV and to identify specific risk factors for NIPPV failure. METHODS: In this observational cohort study at the two intensive care units of a tertiary center, we identified consecutive patients with ALI who were initially treated with NIPPV. Data on demographics, APACHE III scores, degree of hypoxemia, ALI risk factors and NIPPV respiratory parameters were recorded. Univariate and multivariate regression analyses were performed to identify risk factors for NIPPV failure. RESULTS: Of 79 consecutive patients who met the inclusion criteria, 23 were excluded because of a do not resuscitate order and two did not give research authorization. Of the remaining 54 patients, 38 (70.3%) failed NIPPV, among them all 19 patients with shock. In a stepwise logistic regression restricted to patients without shock, metabolic acidosis (odds ratio 1.27, 95% confidence interval (CI) 1.03 to 0.07 per unit of base deficit) and severe hypoxemia (odds ratio 1.03, 95%CI 1.01 to 1.05 per unit decrease in ratio of arterial partial pressure of O2 and inspired O2 concentration--PaO2/FiO2) predicted NIPPV failure. In patients who failed NIPPV, the observed mortality was higher than APACHE predicted mortality (68% versus 39%, p < 0.01). CONCLUSION: NIPPV should be tried very cautiously or not at all in patients with ALI who have shock, metabolic acidosis or profound hypoxemia.

Acute Disease↗

PubMed2006

The initial Mayo Clinic experience using high-frequency oscillatory ventilation for adult patients: a retrospective study.

BACKGROUND: High-frequency oscillatory ventilation (HFOV) was introduced in our institution in June 2003. Since then, there has been no protocol to guide the use of HFOV, and all decisions regarding ventilation strategies and settings of HFOV were made by the treating intensivist. The aim of this study is to report our first year of experience using HFOV. METHODS: In this retrospective study, we reviewed all 14 adult patients, who were consecutively ventilated with HFOV in the intensive care units of a tertiary medical center, from June 2003 to July 2004. RESULTS: The mean age of the patients was 56 years, 10 were males, and all were whites. The first day median APACHE II score and its predicted hospital mortality were 35 and 83%, respectively, and the median SOFA score was 11.5. Eleven patients had ARDS, two unilateral pneumonia with septic shock, and one pulmonary edema. Patients received conventional ventilation for a median of 1.8 days before HFOV. HFOV was used 16 times for a median of 3.2 days. Improvements in oxygenation parameters were observed after 24 hours of HFOV (mean PaO2/FIO2 increased from 82 to 107, P < 0.05; and the mean oxygenation index decreased from 42 to 29; P < 0.05). In two patients HFOV was discontinued, in one because of equipment failure and in another because of severe hypotension that was unresponsive to fluids. No change in mean arterial pressure, or vasopressor requirements was noted after the initiation of HFOV. Eight patients died (57 %, 95% CI: 33-79); life support was withdrawn in six and two suffered cardiac arrest. CONCLUSION: During our first year of experience, HFOV was used as a rescue therapy in very sick patients with refractory hypoxemia, and improvement in oxygenation was observed after 24 hours of this technique. HFOV is a reasonable alternative when a protective lung strategy could not be achieved on conventional ventilation.

Journal Article↗

PubMed2006

Review article: age related alterations in respiratory function - anesthetic considerations.

PURPOSE: This review examines the effect of aging on pulmonary reserve. Special emphasis is placed on how anesthetic and surgical factors may impose substantial stresses on the respiratory system of elderly patients, leading to increased risk for postoperative pulmonary complications including respiratory failure. SOURCE: A MEDLINE-based English-language literature search was undertaken for the period 1966-2006, and an EMBASE search covered the overlapping period 1988-2006. Selected articles were limited to those applying to elderly subjects/patients. PRINCIPAL FINDINGS: Age-related loss of the lung static recoil forces, stiffening of the chest wall and diminished alveolar surface area lead to a decrease in vital capacity, an increase in residual volume, decrease in expiratory flows and increased ventilation-perfusion heterogeneity. Respiratory muscle strength consistently declines with age further increasing the work of breathing. While gas exchange may be well preserved at rest and during exertion, pulmonary reserve is diminished, and under conditions of positive fluid balance, positioning for surgery, and increased metabolic demand, postoperative respiratory failure can occur. Increased sensitivity to respiratory depressants and muscle weakness pose additional risks for the development of postoperative respiratory complications in elderly patients. Regional anesthetic techniques provide for superior postoperative analgesia, without necessarily altering the frequency of postoperative pulmonary complications in the older surgical population. CONCLUSION: Alterations in respiratory physiology associated with aging must be appreciated to anticipate and minimize potential complications associated with surgery and anesthesia in the elderly. Individualized care to optimize preoperative cardiorespiratory function, minimize intraoperative respiratory pertubations, and to gently restore postoperative pulmonary function are essential anesthetic goals for elderly patients who require surgery.

Aged↗

PubMed2006

Intraoperative tidal volume as a risk factor for respiratory failure after pneumonectomy.

BACKGROUND: Respiratory failure is a leading cause of postoperative morbidity and mortality in patients undergoing pneumonectomy. The authors hypothesized that intraoperative mechanical ventilation with large tidal volumes (VTs) would be associated with increased risk of postpneumonectomy respiratory failure. METHODS: Patients undergoing elective pneumonectomy at the authors' institution from January 1999 to January 2003 were studied. The authors collected data on demographics, relevant comorbidities, neoadjuvant therapy, pulmonary function tests, site and type of operation, duration of surgery, intraoperative ventilator settings, and intraoperative fluid administration. The primary outcome measure was postoperative respiratory failure, defined as the need for continuation of mechanical ventilation for greater than 48 h postoperatively or the need for reinstitution of mechanical ventilation after extubation. RESULTS: Of 170 pneumonectomy patients who met inclusion criteria, 30 (18%) developed postoperative respiratory failure. Causes of postoperative respiratory failure were acute lung injury in 50% (n = 15), cardiogenic pulmonary edema in 17% (n = 5), pneumonia in 23% (n = 7), bronchopleural fistula in 7% (n = 2), and pulmonary thromboembolism in 3% (n = 1). Patients who developed respiratory failure were ventilated with larger intraoperative VT than those who did not (median, 8.3 vs. 6.7 ml/kg predicted body weight; P < 0.001). In a multivariate regression analysis, larger intraoperative VT (odds ratio, 1.56 for each ml/kg increase; 95% confidence interval, 1.12-2.23) was associated with development of postoperative respiratory failure. The interaction between larger VT and fluid administration was also statistically significant (odds ratio, 1.36; 95% confidence interval, 1.05-1.97). CONCLUSION: Mechanical ventilation with large intraoperative VT is associated with increased risk of postpneumonectomy respiratory failure.

Aged↗

PubMed2006

Fresh frozen plasma and platelet transfusion for nonbleeding patients in the intensive care unit: benefit or harm?

OBJECTIVE: Whereas restrictive red cell transfusion has become a standard of care for the critically ill, evidenced-based indications for use of other blood components such as fresh frozen plasma (FFP) and platelet transfusions are limited. We searched the National Library of Medicine PubMed database as well as references of retrieved articles and summarized the current evidence for the use of FFP and platelet transfusions in critically ill patients. RESULTS: Routine coagulation tests are poor determinants of bleeding risk in critically ill patients with coagulopathy. FFP transfusion has limited efficacy and is associated with significant morbidity in critically ill patients, in particular, pulmonary edema and acute lung injury. Routine minimally invasive critical care procedures can be safely performed by experienced clinicians in the setting of mildly abnormal coagulation test results, and there is no evidence that FFP transfusion alters the risk of bleeding. For platelet transfusion, the American Society of Clinical Oncology has developed practice guidelines designed for oncology patients. However, because the pathophysiology of thrombocytopenia in critically ill patients often differs from that of thrombocytopenia in oncology patients, published guidelines for oncology patients may not be applicable. CONCLUSION: Because the risk-benefit ratio of a liberal FFP or platelet transfusion strategy for critically ill patients may not be favorable, randomized controlled trials are warranted for evaluating a restrictive vs. liberal FFP or platelet transfusion strategy for nonbleeding patients in the intensive care unit.

Blood Component Transfusion↗

PubMed2006

Pulmonary edema after transfusion: how to differentiate transfusion-associated circulatory overload from transfusion-related acute lung injury.

OBJECTIVE: Pulmonary edema is an under-recognized and potentially serious complication of blood transfusion. Distinct mechanisms include adverse immune reactions and circulatory overload. The former is associated with increased pulmonary vascular permeability and is commonly referred to as transfusion-related acute lung injury (TRALI). The latter causes hydrostatic pulmonary edema and is commonly referred to as transfusion-associated circulatory overload (TACO). In this review article we searched the National Library of Medicine PubMed database as well as references of retrieved articles and summarized the methods for differentiating between hydrostatic and permeability pulmonary edema. RESULTS: The clinical and radiologic manifestations of TACO and TRALI are similar. Although echocardiography and B-type natriuretic peptide measurements may aid in the differential diagnosis between hydrostatic and permeability pulmonary edema, invasive techniques such as right heart catheterization and the sampling of alveolar fluid protein are sometimes necessary. The diagnostic differentiation is especially difficult in critically ill patients will multiple comorbidities so that the cause of edema may only be determined post hoc based on the clinical course and response to therapy. Guided by available evidence, we present an algorithm for establishing the pretest probability of TRALI as opposed to TACO. The decision to test donor and recipient blood for immunocompatibility may be made on this basis. CONCLUSIONS: The distinction between hydrostatic (TACO) and permeability (TRALI) pulmonary edema after transfusion is difficult, in part because the two conditions may coexist. Knowledge of strengths and limitations of different diagnostic techniques is necessary before initiation of complex TRALI workup.

Blood Circulation↗

PubMed2006

B-type natriuretic peptide in the assessment of acute lung injury and cardiogenic pulmonary edema.

OBJECTIVE: The role of plasma B-type natriuretic peptide (BNP) in critically ill patients with acute pulmonary edema is controversial. We postulated that a low BNP level would exclude cardiac dysfunction as the principal cause of pulmonary edema and therefore help in the diagnosis of acute lung injury. DESIGN: A retrospective derivation cohort was followed by a prospective validation cohort of consecutive patients with acute pulmonary edema admitted to three intensive care units. BNP was measured within 24 hrs from onset. Critical care experts blinded to BNP results integrated clinical data with the course of disease and response to therapy and served as the reference standard. SETTING: Three intensive care units at the tertiary center. PATIENTS: Consecutive critically ill patients with acute pulmonary edema. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In a derivation cohort of 84 patients, a BNP threshold of <or=250 pg/mL had a specificity of 87% and sensitivity of 48% for the diagnosis of acute lung injury. High specificity of BNP (90%, likelihood ratio of 3.9) was confirmed in a validation cohort of 120 consecutive patients, 52 (43%) of whom had acute lung injury. Notably, 32% of patients with acute lung injury had concomitant cardiac dysfunction. The median time from the onset of pulmonary edema to BNP testing was 3 hrs. The accuracy of BNP (area under receiver operator curve, 0.71) was comparable with pulmonary artery occlusion pressure (area under receiver operator curve, 0.66) and superior to ejection fraction (area under receiver operator curve, 0.60) in subgroups of patients in whom these tests were performed. The accuracy of BNP improved when patients with renal insufficiency were excluded (area under receiver operator curve, 0.82). CONCLUSION: When measured early after the onset of acute pulmonary edema, a BNP level of <250 pg/mL supports the diagnosis of acute lung injury. The high rate of cardiac and renal dysfunction in critically ill patients limits the discriminative role of BNP. No level of BNP could completely exclude cardiac dysfunction.

Acute Disease↗

PubMed2006

Evidence-based red cell transfusion in the critically ill: quality improvement using computerized physician order entry.

OBJECTIVE: The implementation of evidence-based practice poses a significant challenge in the intensive care unit. In this quality improvement intervention we assessed the effect of an institutional protocol and computerized decision support for red cell transfusion in the critically ill. DESIGN: We compared processes of care and outcomes during the two 3-month periods before and after the introduction of a multidisciplinary quality improvement intervention. SETTING: Multidisciplinary intensive care units--medical, surgical, and mixed--in a tertiary academic center. PATIENTS: Consecutive critically ill patients with anemia (hemoglobin of <10 g/dL). INTERVENTION: Using the computerized provider order entry, we developed an evidence-based decision algorithm for red cell transfusion in adult intensive care units. MEASUREMENTS AND MAIN RESULTS: We collected information on demographics, diagnosis, severity of illness, transfusion complications, and laboratory values. The main outcome measures were number of transfusions, proportion of patients who were transfused outside evidence-based indications, transfusion complications, and adjusted hospital mortality. The mean number of red cell transfusions per intensive care unit admission decreased from 1.08 +/- 2.3 units before to 0.86 +/- 2.3 units after the protocol (p<.001). We observed a marked decrease in the percentage of patients receiving inappropriate transfusions (17.7% vs. 4.5%, p< .001). The rate of transfusion complications was also lower in the period after the protocol (6.1% vs. 2.7%, p = .015). In the multivariate analysis, protocol introduction was associated with decreased likelihood of red cell transfusion (odds ratio, 0.43; 95% confidence interval, 0.30 to 0.62). Adjusted hospital mortality did not differ before and after protocol implementation (odds ratio, 1.12; 95% confidence interval, 0.69 to 1.8). CONCLUSIONS: The implementation of an institutional protocol and decision support through a computerized provider order entry effectively decreased inappropriate red cell transfusions.

Algorithms↗

PubMed2006

Transfusion-related acute lung injury and pulmonary edema in critically ill patients: a retrospective study.

BACKGROUND: Using the recent Consensus Panel recommendations, we sought to describe the incidence of transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) in critically ill patients. STUDY DESIGN AND METHODS: Consecutive patients at four intensive care units (ICUs) who did not require respiratory support at the time of transfusion were identified with custom electronic surveillance system that prospectively tracks the time of transfusion and onset of respiratory support. Respiratory failure was defined as the onset of noninvasive or invasive ventilator support within 6 hours of transfusion. Experts blinded to specific transfusion factors categorized the cases of pulmonary edema as permeability edema (suspected or possible TRALI) or hydrostatic edema (TACO) according to predefined algorithm. In a nested case-control design, transfusion variables and lung injury risk factors were compared between the TRALI cases and controls matched by age, sex, and admission diagnosis. RESULTS: There were 8902 units transfused in 1351 patients of whom 94 required new respiratory support within 6 hours of transfusion. Among 49 patients with confirmed acute pulmonary edema, experts identified 7 cases with suspected TRALI, 17 patients with possible TRALI, and 25 cases with TACO. The incidence of suspected TRALI was 1 in 1271 units transfused; possible TRALI, 1 in 534 per unit transfused; and TACO, 1 in 356 per unit transfused. When adjusted for sepsis and fluid balance in a stepwise conditional logistic regression analysis, patients who developed acute lung injury (suspected or possible TRALI) received larger amount of plasma (odds ratio 3.4, 95% confidence interval 1.2-10.2, for each liter infused; p = 0.023). CONCLUSION: In the ICU, pulmonary edema frequently occurs after blood transfusion. The association between infusion of plasma and the development of suspected or possible TRALI may have important implications with regards to etiology and prevention of this syndrome.

Aged↗

PubMed2006

The effects of the alveolar recruitment maneuver and positive end-expiratory pressure on arterial oxygenation during laparoscopic bariatric surgery.

Abnormalities in gas exchange that occur during anesthesia are mostly caused by atelectasis, and these alterations are more pronounced in morbidly obese than in normal weight subjects. Sustained lung insufflation is capable of recruiting the collapsed areas and improving oxygenation in healthy patients of normal weight. We tested the effect of this ventilatory strategy on arterial oxygenation (Pao2) in patients undergoing laparoscopic bariatric surgery. After pneumoperitoneum was accomplished, the recruitment group received up to 4 sustained lung inflations with peak inspiratory pressures up to 50 cm H2O, which was followed by ventilation with 12 cm H2O positive end-expiratory pressure (PEEP). The patient's lungs in the control group were ventilated in a standard fashion with PEEP of 4 cm H2O. Variables related to gas exchange, respiratory mechanics, and hemodynamics were compared between recruitment and control groups. We found that alveolar recruitment effectively increased intraoperative Pao2 and temporarily increased respiratory system dynamic compliance (both P < 0.01). The effects of alveolar recruitment on oxygenation lasted as long as the trachea was intubated, and lungs were ventilated with high PEEP, but soon after tracheal extubation, all the beneficial effects on oxygenation disappeared. The mean number of vasopressor treatments given during surgery was larger in the recruitment group compared with the control group (3.0 versus 0.8; P = 0.04). In conclusion, our data suggest that the use of alveolar recruitment may be an effective mode of improving intraoperative oxygenation in morbidly obese patients. Our results showed the effect to be short lived and associated with more frequent intraoperative use of vasopressors.

Adult↗

PubMed2006

A review of red cell transfusion in the neurological intensive care unit.

The treatment of anemia in critically ill patients has changed significantly in the past decade with a major shift toward restrictive blood-transfusion strategy. There is a paucity of studies regarding the approach toward anemia in the neurological critical care population. Anemia is a complex problem in this group of patients because of the extreme sensitivity of brain tissue to changes in the cerebral perfusion pressure and oxygen deficit. Most of the evidence regarding management of anemia and optimal hematocrit threshold is based on animal experiments and observational studies. Recent studies have shown a mixed response in the local oxygen saturations and patient outcomes after blood transfusion in neurological critically ill patients. Although there is little reason to suspect that restrictive transfusion protocols would be detrimental, further studies are needed to determine optimal transfusion threshold in this population.

Anemia↗

PubMed2006

Repeat percutaneous tracheostomy in the neurocritically ill patient.

INTRODUCTION: Percutaneous tracheostomy is a widely used and accepted method for long-term mechanical ventilation and airway protection. Neurocritically ill patients sometimes require repeat tracheostomy, which is traditionally considered a relative contraindication for percutaneous procedure. The aim of this study was to determine the safety of repeat percutaneous tracheostomy in neurocritically ill patients with a history of previous tracheostomy. METHODS: In the 16-bed academic neurointensive care unit, we prospectively enrolled patients who needed new tracheostomy placement for airway protection or prolonged mechanical ventilation and had previously undergone percutaneous tracheostomy placement. We collected data on indications, procedure, periprocedural complications, and outcome of repeated tracheostomy. RESULTS: Between January 2001 and October 2005, we enrolled 12 consecutive patients (mean age 35.4 +/- 7.0 years) who underwent repeat percutaneous tracheostomy. Head injury was the most common underlying diagnosis (seven patients, 58%). Tracheostomy tube placement was easy and successful in all patients, and none of the patients needed conversion to surgical tracheostomy. In three patients, ultrasound-guided needle aspiration was used before the procedure to confirm the position of the trachea. No patients died or experienced serious complication related to the procedure. Two patients (17%) had a minor periprocedural bleeding, which was controlled with local compression. Long-term outcome was poor, with only two patients alive and off the ventilator at hospital discharge, both with serious disability. CONCLUSION: Repeat percutaneous tracheostomy can be performed safely in neurocritically ill patients who have undergone previous tracheostomy.

Adult↗

PubMed2006

Mechanical ventilation in patients with Guillain-Barré syndrome.

BACKGROUND: Patients with Guillain-Barré syndrome are commonly exposed to prolonged mechanical ventilation. Specific data on ventilatory management of these patients have been limited. OBJECTIVE: To describe the practice of mechanical ventilation in patients with Guillain-Barré syndrome and evaluate risk factors for morbidity and mortality. METHODS: We describe a historical cohort of mechanically ventilated patients with Guillain-Barré syndrome in a tertiary-care center. We extracted database information on demographics, severity of illness, pulmonary function, and ventilatory management for the period 1976 to 1996. Primary outcomes were development of pulmonary complications, duration of ventilatory support, and mortality. RESULTS: Fifty-four patients met the inclusion criteria. After 1990, lower tidal volume (p = 0.031) and higher positive end-expiratory pressure (p = 0.003) were used than during the 1976 to 1990. Outcomes did not change significantly during the studied period. Forty-six patients (85%) survived to hospital discharge, and 39 (72%) were alive at 1-year follow-up. Ventilator-associated pneumonia was the most frequent complication (56%) and was associated with prolonged mechanical ventilation (p < 0.01). Atelectasis developed in 49%, and acute lung injury in 13%. All but 6 patients (89%) received tracheostomy. In 14 patients (30%) tracheostomy was placed > or = 14 days after intubation. When adjusted for atelectasis and severity of illness in a stepwise logistic regression analysis, delayed tracheostomy was associated with the development of ventilator-associated pneumonia (odds ratio 8.2, p = 0.029). CONCLUSIONS: Changes in ventilator practice did not affect outcomes of mechanically ventilated patients with Guillain-Barré syndrome. The majority of patients received tracheostomy, which should be considered early in the course of respiratory failure.

Adult↗

PubMed2005

The influence of missing components of the Acute Physiology Score of APACHE III on the measurement of ICU performance.

OBJECTIVE: To determine the impact of missing Acute Physiology Score (APS) values on risk-adjusted mortality. DESIGN: Retrospective review of prospectively collected Acute Physiology and Chronic Health Evaluation (APACHE) III database. SETTING: The intensive care units (ICUs) of an academic medical center. PATIENTS: 38,411 patients admitted to ICU between October 1994 and December 2003. MEASUREMENTS AND RESULTS: Data were collected on ICU type, missing first ICU day APS values, predicted and observed hospital mortality, standardized mortality ratio (SMR), 95% confidence interval (CI), odds ratio (OR). The overall observed and predicted hospital mortality rates were 8.7% and 10.8%, respectively, with SMR of 0.806 (95% CI 0.779-0.834). Complete data were available in 829 (2.2%). Vital signs were missing in almost none and serum albumin and bilirubin in over 80% of the patients. The number of missing variables was higher in less sick and surgical ICU patients. Logistic regression analysis showed that the risk of dying in the hospital was significantly associated with the number of missing APS variables (OR 1.058, 95% CI 1.027-1.090) when adjusted for the severity of illness. The risk of death was also associated with the type of missing variables. CONCLUSIONS: Since missing APS values may lead to underestimation of the predicted mortality rates, the number and type of missing variables should be taken into consideration when assessing the performance of an ICU. Unless data collection is standardized, future prognostic models should use variables that are routinely measured in most critically ill patients without sacrificing statistical precision.

APACHE↗

PubMed2005

Ventilator settings as a risk factor for acute respiratory distress syndrome in mechanically ventilated patients.

OBJECTIVE: A single-center retrospective study initial recently identified ventilator settings as a major risk factor for the development of acute respiratory distress syndrome (ARDS) in mechanically ventilated patients who do not have ARDS from the outset. We tested this hypothesis in a larger sample of patients prospectively enrolled in a multicenter study on mechanical ventilation. DESIGN AND SETTING: From a large international mechanical ventilation study database we identified patients who required mechanical ventilation for 48 h or more but did not have ARDS at the onset of mechanical ventilation. We extracted information on demographics, initial severity of illness, ventilator settings and major underlying ARDS risk factors. Primary outcome was development of ARDS after the onset of mechanical ventilation. MEASUREMENTS AND RESULTS: Of 3,261 mechanically ventilated patients who did not have ARDS at the outset 205 (6.2%) developed ARDS 48 h or more after the onset of mechanical ventilation. Multivariate logistic regression analysis adjusted for baseline patient characteristics (age, gender, Simplified Acute Physiology Score, hypoxemia) and underlying ARDS risk factors (sepsis, trauma, pneumonia) found the development of ARDS to be associated with the initial ventilator settings: high tidal volume (odds ratio 2.6 for tidal volume>700 ml), high peak airway pressure (odds ratio 1.6 for peak airway pressure>30 cmH2O), and high positive end-expiratory pressure (odds ratio 1.7 for end-expiratory pressure>5 cmH2O). CONCLUSIONS: The association with the potentially injurious initial ventilator settings, in particular large tidal volumes, suggests that ARDS in mechanically ventilated patients is in part a preventable complication. This hypothesis needs to be tested in a prospective study.

Female↗

PubMed2005

Hypercapnic acidosis impairs plasma membrane wound resealing in ventilator-injured lungs.

The objective of this study was to assess the effects of hypercapnic acidosis on lung cell injury and repair by confocal microscopy in a model of ventilator-induced lung injury. Three groups of normocapnic, hypocapnic, and hypercapnic rat lungs were perfused ex vivo, either during or after injurious ventilation, with a solution containing the membrane-impermeant label propidium iodide. In lungs labeled during injurious ventilation, propidium iodide fluorescence identifies all cells with plasma membrane wounds, both permanent and transient, whereas in lungs labeled after injurious ventilation propidium iodide fluorescence identifies only cells with permanent plasma membrane wounds. Hypercapnia minimized the adverse effects of high-volume ventilation on vascular barrier function, whereas hypocapnia had the opposite effect. Despite CO2-dependent differences in lung mechanics and edema the number of injured subpleural cells per alveolus was similar in the three groups (0.48 +/- 0.34 versus 0.51 +/- 0.19 versus 0.43 +/- 0.20 for hypocapnia, normocapnia, and hypercapnia, respectively). However, compared with normocapnia the probability of wound repair was significantly reduced in hypercapnic lungs (63 versus 38%; p < 0.02). This finding was subsequently confirmed in alveolar epithelial cell scratch models. The potential relevance of these observations for lung inflammation and remodeling after mechanical injury is discussed.

Acidosis, Respiratory↗

PubMed2005

Long-haul air travel before major surgery: a prescription for thromboembolism?

OBJECTIVE: To investigate the Incidence of postoperative venous thromboembolism (VTE) in patients who had flown long distances before major surgery. PATIENTS AND METHODS: Using the Mayo Clinic computerized patient database, we Identified patients who had flown more than 5000 km before major surgery (travelers) and had experienced an episode of clinically significant VTE within 28 days after surgery. Individual medical records were reviewed for the diagnosis of VTE, pertinent risk factors, and outcome. We compared the Incidence of VTE in travelers to the incidence of VTE in patients from North America (nontravelers) undergoing similar surgical procedures. RESULTS: Eleven patients met our criteria for long-haul air travel and clinically significant VTE within 28 days after surgery. Compared with nontravelers undergoing similar surgical procedures, long-haul travelers had a higher Incidence of VTE (4.9% vs 0.15%; P < .001). Compared with nontravelers who developed VTE, travelers were younger (P = .006), developed VTE earlier in the postoperative course (P = .01), had higher American Society of Anesthesiologists physical status classification (P = .02), and had higher prevalence of smoking (P = .007). Of the 11 travelers with VTE, 10 were of Middle Eastern origin. CONCLUSION: Prolonged air travel before major surgery significantly increases the risk of perioperative VTE. Such patients should receive more Intensive VTE prophylactic measures during the flight and throughout the perioperative period.

Adult↗

PubMed2005

Transfusion-related acute lung injury.

Transfusion-related acute lung injury (TRALI) is characterized by the sudden development of noncardlogenic pulmonary edema (acute lung Injury) after transfusion of blood products. Poor awareness of TRALI outside of the blood transfusion medicine community has led to a serious underestimation of this condition, currently the most Important severe complication of blood transfusion. Concern for the transfer of donor antileukocyte antibodies has prompted major changes in the management of the blood supply in some countries; however, recent studies have suggested alternative pathophyslological mechanisms for TRALI related to the shelf life of cellular blood products. Although all blood products have been implicated, most reported cases were associated with fresh frozen plasma, red blood cell, and platelet transfusions. Because many patients have additional predisposing factors for acute lung injury, carefully designed prospective studies are needed to fully assess attributable risk related to transfusion. The treatment of TRALI is supportive, and the prognosis is generally better than for other causes of acute lung Injury. As many as one third of all patients who develop acute lung injury have been exposed to blood products. TRALI may be an important and potentially preventable cause of acute lung injury.

Global Health↗