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1.
Front Cardiovasc Med ; 10: 1170275, 2023.
Article in English | MEDLINE | ID: mdl-37424899

ABSTRACT

Introduction: At cruising altitude, the cabin pressure of passenger aircraft needs to be adjusted and, therefore, the oxygen content is equivalent to ambient air at 2,500 masl, causing mild desaturation and a rising pulmonary vascular resistance (PVR) in healthy subjects. For Fontan patients with passive pulmonary perfusion, a rising PVR can cause serious medical problems. The purpose of this fitness to fly investigation (FTF) is to assess the risk of air travel for children and adolescents after Fontan palliation. Methods: We investigated 21 Fontan patients [3-14y] in a normobaric hypoxic chamber at a simulated altitude of 2,500 m for 3 h. Oxygen saturation, heart rate, and regional tissue saturation in the forehead (NIRS) were measured continuously. Before entering the chamber, after 90 and 180 min in the hypoxic environment, blood gas analysis and echocardiography were performed. Results: Heart rate and blood pressure did not show significant intraindividual changes. Capillary oxygen saturation (SaO2) decreased significantly after 90 min by a mean of 5.6 ± 2.87% without further decline. Lactate, pH, base excess, and tissue saturation in the frontal brain did not reach any critical values. In the case of open fenestration between the tunnel and the atrium delta, P did not increase, indicating stable pulmonary artery pressure. Conclusion: All 21 children finished the investigation successfully without any adverse events, so flying short distance seems to be safe for most Fontan patients with good current health status. As the baseline oxygen saturation does not allow prediction of the maximum extent of desaturation and adaption to a hypoxic environment takes up to 180 min, the so-called hypoxic challenge test is not sufficient for these patients. Performing an FTF examination over a period of 180 min allows for risk assessment and provides safety to the patients and their families, as well as the airline companies.

2.
Acta Anaesthesiol Scand ; 62(9): 1215-1222, 2018 10.
Article in English | MEDLINE | ID: mdl-29851024

ABSTRACT

BACKGROUND: Haemodynamic instability during the induction of anaesthesia and surgery is common and may be related to hypovolaemia caused by pre-operative fasting or chronic diuretic therapy. The aim of our prospective, controlled, randomized study was to test the hypothesis that a predefined fluid bolus given prior to general anaesthesia for minor surgery would increase haemodynamic stability during anaesthetic induction. METHODS: Two hundred and nineteen fairly healthy adult patients requiring minor surgery were enrolled. All received standard treatment, including a pulse contour analysing device for non-invasive measurement of cardiac index. Infusion therapy was started in all patients at induction. The intervention group (106 patients) was randomized to receive an additional fluid bolus of 8 mL/kg Ringer's acetate solution before the induction of anaesthesia. The primary endpoint was the incidence of haemodynamic instability, defined as a significant reduction of blood pressure or cardiac index during induction of anaesthesia. RESULTS: The interventional group had a lesser incidence of haemodynamic instability during induction (41.5% vs 56.6%, P = .025). This group also had higher cardiac index, stroke volume index, systolic and mean blood pressure and a greater left ventricular end-diastolic area. CONCLUSIONS: A fluid bolus prior to anaesthesia reduced the incidence of haemodynamic instability during induction of general anaesthesia. The total fluid volume was slightly greater in the intervention group compared to the control group (1370 ± 439 mL vs 1219 ± 483 mL, P = .007). We conclude that a defined fluid bolus can help stabilizing haemodynamics in patients undergoing general anaesthesia.


Subject(s)
Fluid Therapy/methods , Hemodynamics/physiology , Intraoperative Complications/prevention & control , Isotonic Solutions/therapeutic use , Minor Surgical Procedures , Preoperative Care/methods , Anesthesia, General , Female , Humans , Infusions, Intravenous , Isotonic Solutions/administration & dosage , Male , Middle Aged , Prospective Studies
3.
Nervenarzt ; 87(3): 246-52, 2016 Mar.
Article in German | MEDLINE | ID: mdl-26910259

ABSTRACT

BACKGROUND: Following treatment on the intensive care unit (ICU) patients often suffer from acute and long-term cognitive deficits. This is true for patients of all age groups but especially for elderly patients who have undergone surgery and develop postoperative delirium (POD) or postoperative cognitive decline (POCD). Both are associated with severe limitations in the quality of life and long-term outcome. OBJECTIVE: Which acute and long-term cognitive effects develop in ICU survivors and how do they influence the outcome? How can POD and POCD be differentiated? METHOD: A selective literature search was carried out. RESULTS: Following surgery POCD can develop within days to weeks, may persist for weeks or months and can lead to problems in attentiveness even under conditions of inconspicuous consciousness. Remission is possible but may take up to more than 12 months. The POD is a phenomenon characterized by disturbances of consciousness and problems in attention, beginning acutely hours and days postoperatively, can persist for days to weeks and remission can be expected within a few days. While POD often has an organic cause, such as an infection, the pathogenesis of POCD has not been sufficiently elucidated. DISCUSSION: Both POD and particularly POCD can lead to a deterioration of cognition following ICU treatment. As efficient treatment still has to be developed preventive methods, such as preoperative screening for risk factors, thorough planning of operative and anesthetic techniques and compensation of risk factors as well as providing assistance to patients, e. g. by a trained nurse should be implemented in the clinical routine more often than is presently the case.


Subject(s)
Cognition Disorders/diagnosis , Cognition Disorders/therapy , Critical Illness/therapy , Delirium/diagnosis , Delirium/therapy , Postoperative Complications/diagnosis , Acute Disease , Chronic Disease , Cognition Disorders/psychology , Critical Care/methods , Critical Illness/psychology , Delirium/psychology , Humans , Intensive Care Units , Postoperative Complications/psychology , Postoperative Complications/therapy , Treatment Outcome
4.
Technol Health Care ; 24(3): 309-15, 2016 May 18.
Article in English | MEDLINE | ID: mdl-26835724

ABSTRACT

BACKGROUND: The intraoperative application of focused transthoracic echocardiography (TTE) is often considered to be restricted. Echocardiography with pocket-sized hand held ultrasound systems has been shown to be feasible in various settings. OBJECTIVE: The aim of this study was to investigate the feasibility of the intraoperative application of pocket-sized echocardiography and the comparison of its imaging quality and diagnostic reliability and variability with a standard ultrasound system. METHODS: After written informed consent, TTE was performed on 40 anaesthetised general, vascular, visceral, thoracic surgical and orthopaedic patients according to the FATE protocol: first, with a pocket-sized and second, with a high-end ultrasound system randomly by two anaesthetists. Imaging quality of four basic and three additional FATE views was rated on an established scale from 1 (impossible) to 5 (perfect). Successful TTE was defined, if one basic FATE views would be rated as grade 4 or 5 or alternatively two views as grade 3. Pathologic findings by both ultrasound devices were documented and imaging quality and pathologic findings were compared. RESULTS: All 40 patients presented acceptable imaging quality, resulting in a success rate of 1.0 (97.5%-CI 0.91-1, p= 0.015). The individual imaging ratings of each view were significantly lower with the pocket-sized system, but still showed acceptable imaging quality. With the high-end device more pathologic findings were detected (107 vs. 87), but none of the relevant or severe pathologies were overseen with the hand-held device. CONCLUSION: The application of a pocket-sized echocardiography device for focused intraoperative TTE is feasible and can appropriate be used for the initial evaluation of relevant pathologies in the operating theatre.


Subject(s)
Anesthesiologists , Echocardiography/instrumentation , Point-of-Care Systems , Aged , Aged, 80 and over , Feasibility Studies , Female , Humans , Male , Middle Aged , Reproducibility of Results
5.
Minerva Anestesiol ; 81(5): 490-6, 2015 May.
Article in English | MEDLINE | ID: mdl-25220551

ABSTRACT

BACKGROUND: Focused transthoracic echocardiography (TTE) is frequently used perioperatively for hemodynamic monitoring and diagnosis of cardiovascular instability, but less commonly intraoperatively. METHODS: To evaluate the feasibility of intraoperative TTE, we enrolled 222 anesthetised patients from August to November 2012 into a prospective observational study. 162 patients underwent TTE examination according to the Focused Assessed Transthoracic Echocardiography (FATE) protocol after positioning and draping for surgery. Sixty additional hemodynamically unstable subjects were examined during anesthesia and surgery. The imaging quality of four FATE views was rated on a scale from 1 (impossible) to 5 (perfect). TTE was assessed as applicable, if at least two of the four basic FATE views were graded 4 or 5, or three views were assessed as grade 3. RESULTS: Imaging quality was unacceptable in 20 patients, resulting in a feasibility rate of 91% (97.5%-CI 0.86-1, P=0.01). TTE was feasible in hemodynamically unstable subjects (91.7%; 97.5%-CI 0.82-1.0), in orthopedic and trauma patients (>95% respectively, [97.5%-CI 0.83-1]) and in abdominal surgery (78%). CONCLUSION: TTE can be applied in the operating theatre during surgery, although its use during abdominal surgery is somewhat limited.


Subject(s)
Anesthesiologists , Cardiovascular Diseases/diagnostic imaging , Echocardiography/methods , Monitoring, Intraoperative/methods , Adult , Aged , Feasibility Studies , Female , Hemodynamics , Humans , Male , Middle Aged , Prospective Studies
6.
Environ Monit Assess ; 186(5): 3091-114, 2014 May.
Article in English | MEDLINE | ID: mdl-24415132

ABSTRACT

Severe rainstorms cause vertical mixing that modifies the internal dynamics (e.g., internal seiche, thermal structure, and velocity filed) in warm polymictic lakes. Yuan Yang Lake (YYL), a subtropical, subalpine, and seasonally stratified small lake in the north-central region of Taiwan, is normally affected by typhoons accompanied with strong wind and heavy rainfall during the summer and fall. In this study, we used the field data, statistical analysis, spectral analysis, and numerical modeling to investigate severe rainstorm-induced mixing in the lake. Statistical determination of the key meteorological and environmental conditions underlying the observed vertical mixing suggests that the vertical mixing, caused by heat loss during severe rainstorms, was likely larger than wind-induced mixing and that high inflow discharge strongly increased heat loss through advection heat. Spectral analysis revealed that internal seiches at the basin scale occurred under non-rainstorm meteorological conditions and that the internal seiches under the rainstorm were modified on the increase of the internal seiche frequencies. Based upon observed frequencies of the internal seiches, a two-dimensional model was simulated and then appropriate velocity patterns of the internal seiches were determined under non-rainstorm conditions. Moreover, the model implemented with inflow boundary condition was conducted for rainstorm events. The model results showed that the severe rainstorms promoted thermal destratification and changed vertical circulation of the basin-scale, internal seiche motion into riverine flow.


Subject(s)
Environmental Monitoring , Lakes/chemistry , Models, Theoretical , Rain , Water Pollutants/analysis , Seasons , Taiwan , Wind
7.
Fortschr Neurol Psychiatr ; 81(12): 679-88, 2013 Dec.
Article in German | MEDLINE | ID: mdl-24307086

ABSTRACT

Taking care of dying people is one of the most difficult obligations of the physician, especially if these patients are suffering from dementia and accordingly when their current capacity to consent is arguable. In this field, numerous ethical and forensic problems arise that have to be considered. Legal medical end-of-life decisions that potentially shorten life (Sterbehilfe) are divided into two categories: direct "Sterbehilfe" refers to stopping life-prolonging measures. Indirect "Sterbehilfe" describes the use of agents to alleviate symptoms of a terminally ill patient which may however, shorten life expectancy. A physician terminating a patient's life based on his own decision and authority of action always acts illegally. This paper describes the current discussion on this issue in Germany considering the medical and legal aspects of it while focussing on patients suffering from dementia and their ability to form and to articulate their own will.


Subject(s)
Death , Dementia , Legislation, Medical/trends , Right to Die , Aged , Aged, 80 and over , Germany , Humans , Physicians , Terminal Care/legislation & jurisprudence , Terminally Ill
9.
Z Gerontol Geriatr ; 40(2): 96-103, 2007 Apr.
Article in German | MEDLINE | ID: mdl-17450409

ABSTRACT

In the past the concept of delirium was associated with different diseases. Even today numerous synonyms of delirium exist. The author gives an overview of the definition of delirium in the past and today. The paper presents epidemiological data, diagnostic criteria and differential diagnoses of delirium for patients suffering from dementia. Pathological mechanisms, risk factors and triggers as well as different forms of delirium for patients suffering from dementia are discussed. Diagnostics and differential diagnostics are discussed and possible medicamentous and non-medicamentous therapy procedures as well as the prevention of delirium are shown. The author points out the necessity of education and training of medical staff to prevent or to diagnose early delirium for patients suffering from dementia and to start therapy as early as possible.


Subject(s)
Delirium/complications , Delirium/diagnosis , Dementia/complications , Dementia/diagnosis , Practice Guidelines as Topic , Aged , Aged, 80 and over , Delirium/classification , Delirium/therapy , Dementia/classification , Dementia/therapy , Diagnosis, Differential , Germany , Humans , Practice Patterns, Physicians' , Prognosis
10.
Microb Ecol ; 48(4): 550-60, 2004 Nov.
Article in English | MEDLINE | ID: mdl-15696388

ABSTRACT

Bacterioplankton community composition (BCC) was monitored in a shallow humic lake in northern Wisconsin, USA, over 3 years using automated ribosomal intergenic spacer analysis (ARISA). Comparison of ARISA profiles of bacterial communities over time indicated that BCC was highly variable on a seasonal and annual scale. Nonmetric multidimensional scaling (MDS) analysis indicated little similarity in BCC from year to year. Nevertheless, annual patterns in bacterioplankton community diversity were observed. Trends in bacterioplankton community diversity were correlated to annual patterns in community succession observed for phytoplankton and zooplankton populations, consistent with the notion that food web interactions affect bacterioplankton community structure in this humic lake. Bacterioplankton communities experience a dramatic drop in richness and abundance each year in early summer, concurrent with an increase in the abundance of both mixotrophic and heterotrophic flagellates. A second drop in richness, but not abundance, is observed each year in late summer, coinciding with an intense bloom of the nonphagotrophic dinoflagellate Peridinium limbatum. A relationship between bacterial community composition, size, and abundance and the population dynamics of Daphnia was also observed. The noted synchrony between these major population and species shifts suggests that linkages across trophic levels play a role in determining the annual time course of events for the microbial and metazoan components of the plankton.


Subject(s)
Bacterial Physiological Phenomena , Plankton/physiology , Water Microbiology , Biodiversity , Ecosystem , Fresh Water/chemistry , Hydrocarbons/analysis , Hydrogen-Ion Concentration , Nitrogen/analysis , Phosphorus/analysis , Population Dynamics , Time Factors , Wisconsin
11.
Microb Ecol ; 46(4): 391-405, 2003 Nov.
Article in English | MEDLINE | ID: mdl-12904915

ABSTRACT

Despite considerable attention in recent years, the composition and dynamics of lake bacterial communities over annual time scales are poorly understood. This study used automated ribosomal intergenic spacer analysis (ARISA) to explore the patterns of change in lake bacterial communities in three temperate lakes over 2 consecutive years. The study lakes included a humic lake, an oligotrophic lake, and a eutrophic lake, and the epilimnetic bacterial communities were sampled every 2 weeks. The patterns of change in bacterial communities indicated that seasonal forces were important in structuring the behavior of the bacterial communities in each lake. All three lakes had relatively stable community composition in spring and fall, but summer changes were dramatic. Summertime variability was often characterized by recurrent drops in bacterial diversity. Specific ARISA fragments derived from these lakes were not constant among lakes or from year to year, and those fragments that did recur in lakes in different years did not exhibit the same seasonal pattern of recurrence. Nonetheless, seasonal patterns observed in 2000 were fairly successful predictors of the rate of change in bacterial communities and in the degree of autocorrelation of bacterial communities in 2001. Thus, seasonal forces may be important structuring elements of these systems as a whole even if they are uncoupled from the dynamics of the individual system components.


Subject(s)
Bacteria/genetics , Biodiversity , Eutrophication/physiology , Seasons , Water Microbiology , DNA Primers , DNA, Ribosomal Spacer/genetics , Electrophoresis , Fluorescence , Fresh Water/analysis , Time Factors , Wisconsin
12.
Fortschr Neurol Psychiatr ; 69(8): 353-8, 2001 Aug.
Article in German | MEDLINE | ID: mdl-11584684

ABSTRACT

The classic literature on pathological laughter and crying emphasizes the difference between incontinence and lability of affect. Pathological laughter and crying as key symptoms of affect incontinence are viewed as the effects of disinhibition of motor synergisms without congruent affect, which is the crucial difference to affect lability. The interpretation as a disinhibitory phenomenon is supported by clinical and electromyographic observations, which found a lack of modulation of intensity in pathological laughter and crying. In 1924, Wilson postulated a supranuclear pontobulbar center for affective synergisms that is controlled by cortex and thalamus. Accordingly, Kleist viewed a combined lesion of thalamic or brainstem structures and corticofugal motor projection systems as the pathoanatomic basis of affect incontinence. Recent work reported the frequent occurrence of affect incontinence with stroke and dementia of the Alzheimer type and thus disagrees with the classical theory. However, the methods used cannot rule out a confounding between affect lability and incontinence.


Subject(s)
Crying/psychology , Laughter/psychology , Mental Disorders/psychology , Brain/pathology , Electromyography , Humans , Mental Disorders/pathology , Mental Disorders/therapy
13.
J Neurotrauma ; 17(2): 113-22, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10709869

ABSTRACT

This study aimed at the investigation of release patterns of neuron specific enolase (NSE) and protein S-100B after traumatic brain injury (TBI) and their association with intracranial pathologic changes as demonstrated in computerized tomography (CT). We analyzed NSE and S-100B concentrations in serial venous blood samples taken one to three days after TBI in 66 patients by the use of immunoluminometric assays. These markers are considered to be specific neurobiochemical indicators of damage to glial (S-100B) or neuronal (NSE) brain tissue. Standardized neurological examination and plani- and volumetric evaluation of computerized tomography scans were performed in all patients. Patients with medium severe to severe TBI [Glasgow Coma Scale (GCS) score at the site of accident < or =12] exhibited significantly higher NSE and S-100B concentrations and a significantly longer release compared to patients with minor head injury (GCS: 13-15). Both, patients with and without visible intracerebral pathology in CT scans exhibited elevated concentrations of NSE and S-100B after TBI and a significant decrease in the follow-up blood samples. Release patterns of S-100B and NSE differed in patients with primary cortical contusions, diffuse axonal injury (DAI), and signs of cerebral edema (ICP) without focal mass lesions. All serum concentrations of NSE and S-100B were significantly correlated with the volume of contusions. The data of the present study indicate that the early release patterns of NSE and S-100 may mirror different pathophysiological consequences of traumatic brain injury.


Subject(s)
Brain Damage, Chronic/diagnostic imaging , Brain Injuries/diagnostic imaging , Brain Injuries/pathology , Brain/diagnostic imaging , Brain/pathology , Phosphopyruvate Hydratase/analysis , S100 Proteins/analysis , Adolescent , Adult , Aged , Biomarkers/analysis , Brain Damage, Chronic/pathology , Calcium-Binding Proteins/analysis , Craniocerebral Trauma/diagnostic imaging , Craniocerebral Trauma/pathology , Glasgow Coma Scale , Humans , Middle Aged , Nerve Growth Factors , S100 Calcium Binding Protein beta Subunit , Time Factors , Tomography, X-Ray Computed
14.
Stroke ; 30(6): 1190-5, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10356098

ABSTRACT

BACKGROUND AND PURPOSE: The study aimed to investigate the predictive value of neurobiochemical markers of brain damage (protein S-100B and neuron-specific enolase [NSE]) with respect to early neurobehavioral outcome after stroke. METHODS: We investigated 58 patients with completed stroke who were admitted to the stroke unit of the Department of Neurology at Magdeburg University. Serial venous blood samples were taken after admission and during the first 4 days, and protein S-100B and NSE were analyzed by the use of immunoluminometric assays. In all patients, lesion topography and vascular supply were analyzed and volume of infarcted brain areas was calculated. The neurological status was evaluated by a standardized neurological examination and the National Institutes of Health Stroke Scale (NIHSS) on admission, at days 1 and 4 on the stroke unit, at day 10, and at discharge from the hospital. Comprehensive neuropsychological examinations were performed in all patients with first-ever stroke event and supratentorial brain infarctions. Functional outcome was measured with the Barthel score at discharge from the hospital. RESULTS: NSE and protein S-100B concentrations were significantly correlated with both volume of infarcted brain areas and NIHSS scores. Patients with an adverse neurological outcome had a significantly higher and significantly longer release of both markers. Neuropsychological impairment was associated with higher protein S-100B release, but this did not reach statistical significance. CONCLUSIONS: Serum concentrations and kinetics of protein S-100B and NSE have a high predictive value for early neurobehavioral outcome after acute stroke. Protein S-100B concentrations at days 2 to 4 after acute stroke may provide valuable information for both neurological status and functional impairment at discharge from the acute care hospital.


Subject(s)
Behavior/physiology , Brain Damage, Chronic/blood , Cerebrovascular Disorders/physiopathology , Cerebrovascular Disorders/psychology , Nervous System/metabolism , Nervous System/physiopathology , Aged , Biomarkers , Cerebrovascular Disorders/blood , Cerebrovascular Disorders/diagnostic imaging , Disability Evaluation , Female , Humans , Male , Middle Aged , Osmolar Concentration , Phosphopyruvate Hydratase/blood , S100 Proteins/blood , Time Factors , Tomography, X-Ray Computed
15.
Biochem Biophys Res Commun ; 245(3): 830-4, 1998 Apr 28.
Article in English | MEDLINE | ID: mdl-9588200

ABSTRACT

Small GTP-binding proteins of the Ras and Rho family participate in various important signalling pathways. Large clostridial cytotoxins inactivate GTPases by UDP-glucosylation. Using Clostridium difficile toxin B-10463 (TcdB) for inactivation of Rho proteins (RhoA/Rac/Cdc42) and Clostridium sordellii lethal toxin-1522 (TcsL) for inactivation of Ras-proteins (Ras/Rac/Ral, Rap) the role of these GTPases in protein kinase C (PKC) stimulation was studied. Phorbol-myristate-acetate (PMA) induced a rapid PKC translocation to and activation in the particulate cell fraction as determined by PKC-activity measurements and Western blots for PKC alpha. These effects were blocked by TcdB inhibiting Rho proteins in endothelial cells, but not in TcsL-treated cells (i.e., cells without Ras activity), suggesting that Rho GTPases (RhoA and/or Cdc42) are the most likely GTP-binding proteins responsible for PKC activation. The Rho requirement for PKC activation/translocation was also verified for human epithelial cells and for lipopolysaccharide-stimulated endothelial cells. In summary, the data presented indicate that Rho protein inhibition blocked PKC translocation/activation in endothelial and epithelial cells.


Subject(s)
Cell Cycle Proteins/antagonists & inhibitors , GTP-Binding Proteins/antagonists & inhibitors , Protein Kinase C/metabolism , ras Proteins/antagonists & inhibitors , Animals , Bronchi/drug effects , Bronchi/metabolism , Cells, Cultured , Endothelium, Vascular/drug effects , Endothelium, Vascular/metabolism , Enzyme Activation , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Humans , Lipopolysaccharides/pharmacology , Swine , Tetradecanoylphorbol Acetate/pharmacology , cdc42 GTP-Binding Protein , rhoA GTP-Binding Protein
16.
Psychol Rep ; 78(3 Pt 1): 939-44, 1996 Jun.
Article in English | MEDLINE | ID: mdl-8711051

ABSTRACT

The authors examined the relationships between Type A behavior and narcissism based on scores of college students in Japan, the United States of America, and the People's Republic of China. The scores on narcissism and Type A behavior differed significantly across the groups, being highest among the Chinese. In all three groups, the Type A scores were significantly and positively correlated with the scores on narcissism, and the latter were significantly and negatively correlated with the scores of mother's care. We refer in this study to cross-cultural comparisons from viewpoints of sociocultural and psychological family structure.


Subject(s)
Cross-Cultural Comparison , Ethnicity/psychology , Mother-Child Relations , Narcissism , Students/psychology , Type A Personality , Adolescent , Adult , China , Cultural Characteristics , Female , Humans , Japan , Male , United States
17.
Science ; 265(5178): 1568-70, 1994 Sep 09.
Article in English | MEDLINE | ID: mdl-17801536

ABSTRACT

Data on the partial pressure of carbon dioxide (CO(2)) in the surface waters from a large number of lakes (1835) with a worldwide distribution show that only a small proportion of the 4665 samples analyzed (less than 10 percent) were within +/-20 percent of equilibrium with the atmosphere and that most samples (87 percent) were supersaturated. The mean partial pressure of CO(2) averaged 1036 microatmospheres, about three times the value in the overlying atmosphere, indicating that lakes are sources rather than sinks of atmospheric CO(2). On a global scale, the potential efflux of CO(2) from lakes (about 0.14 x 10(15) grams of carbon per year) is about half as large as riverine transport of organic plus inorganic carbon to the ocean. Lakes are a small but potentially important conduit for carbon from terrestrial sources to the atmospheric sink.

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