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PubMed2003

The use of isotopes to identify landfill gas effects on groundwater.

An evaluation of the source of volatile organic compounds in groundwater samples was performed at a landfill in southern California. The 3H (tritium) content of the water in leachate and water from the gas-collection system (condensed water and entrained water droplets) and the delta 13C and 14C content of the inorganic carbon in landfill gas CO2, leachate, and gas-collection system water were used to characterize the dissolved inorganic carbon (DIC) inside the landfill, while the same parameters were monitored in groundwater samples from affected monitoring wells and an unaffected well. Tritium levels from leachate and gas-collection system condensate ranged from approximately 2000 TU to over 4000 TU, orders of magnitude higher than unaffected groundwater. The average 14C content of DIC in the landfill pore-water samples was 121 pMC and the 14C content of unaffected groundwater DIC was 93 pMC, while the 14C content of the dissolved inorganic carbon in groundwater with VOC detections ranged from 105 to 119 pMC. The delta 13C of DIC in pore water was consistently above 0 per thousand and the delta 13C of unaffected groundwater DIC was -20.3 per thousand, while the delta 13C of DIC in affected groundwater samples was increased from -17.3 to -13.2 per thousand. The increases in both delta 13C and 14C in landfill gas-impacted groundwater DIC generally correlated with the number of volatile organic compounds detected and their concentrations. Based on the tritium and DIC 14C levels in leachate and water from the gas-collection system compared to those of unaffected water, significant increases in the tritium content of the water would be expected to accompany VOC detections and increases in delta 13C and 14C caused by landfill water. The results rule out landfill water as the VOC source, leaving landfill gas as the source. The identities and concentrations of the specific VOCs in affected groundwater samples varied among wells as well as between two leachate samples, ruling out the use of a VOC "fingerprint" for leachate or landfill gas to be compared to groundwater VOC concentrations.

Carbon Isotopes↗

PubMed2002

Transoesophageal echocardiography shows high risk of gas embolism during laparoscopic hepatic resection under carbon dioxide pneumoperitoneum.

BACKGROUND: The ultrasonically activated scalpel (UAS) enables safe and effective laparoscopic tissue dissection, making hepatic resection feasible. This study compared blood loss and risk of gas embolism using the UAS during open hepatic resection and laparoscopic hepatic resection. METHODS: Female pigs were divided into two groups for laparoscopic (n = 7) and open (n = 5) left hepatic lobectomy. The UAS was used for both tissue cutting and coagulation. Laparoscopic liver resection was performed under carbon dioxide pneumoperitoneum (intraperitoneal pressure 12 mmHg). During surgery animals were monitored haemodynamically by an arterial line and Swan-Ganz catheter. Two-dimensional transoesophageal echocardiography (2D-TEE) was used to detect gas emboli with special attention to the right atrium and ventricle. Gas emboli were graded according to size, and correlated with haemodynamic and blood gas data. RESULTS: During open and laparoscopic hepatic resection the UAS resulted in minimal blood loss and effective tissue dissection. No air embolism was seen during open surgery. With laparoscopic hepatic resection 2D-TEE revealed gas embolism in all animals. Gas embolism was accompanied by cardiac arrhythmia in four of seven animals. No direct correlation was observed between embolism episodes and blood gas variables. There were no deaths after episodes of embolization. A significant decrease in arterial partial pressure of oxygen was seen at the end of the laparoscopic procedure in all animals. CONCLUSION: The UAS causes minimal blood loss during both open and laparoscopic hepatic resection. Laparoscopic liver dissection under carbon dioxide pneumoperitoneum carries a high risk of gas embolism.

Animals↗

PubMed2001

A prospective study of the association between home gas appliance use during infancy and subsequent dust mite sensitization and lung function in childhood.

BACKGROUND: Home gas appliance use has been associated with child respiratory illness but prospective data on the relationship between infant exposure and the development of child allergic disease has not been readily available. OBJECTIVES: (a) To determine if home gas appliance use is associated with increased risk of house dust mite (HDM) sensitization. (b) To examine whether any association between current home gas use and airway obstruction is influenced by HDM sensitization. METHODS DESIGN: an 8-year follow-up birth cohort study of children born during 1988 and 1989. PARTICIPANTS: a population-based sample (n = 498) of children who participated in the Tasmanian Infant Health Survey (TIHS) and resided in Northern Tasmania in 1997 (84% of eligible children). MAIN OUTCOME MEASURES: (a) Skin prick test reaction to nine allergens, including Dermatophagoides pteronyssinus (Der p 1) and Dermatophagoides farinae (Der f 1). (b) Spirometric lung function indices, including forced expiratory volume in one second (FEV(1)) and forced vital capacity (FVC). RESULTS: The relative risk for home gas appliance use at 1 month of age and HDM sensitization was 1.98 (1.04, 3.79) in a cohort analysis with confounder matching. Current home gas use was also associated with HDM sensitization (ARR 1.73 (1.43, 2.76)). Current home gas use was related to a stronger (P = 0.006) reduction in the FEV(1) : FVC ratio among HDM-sensitive children (adjusted difference - 6.2% (- 10.0 to - 2.4)) than non-HDM-sensitive children (adjusted difference - 0.3% (- 2.5 to 1.8)). CONCLUSION: Indoor pollutants from gas combustion may increase the likelihood of initial sensitization to HDM and play a role in the development of atopic asthma. HDM-sensitized children may be more vulnerable to indoor pollutant-induced airway obstruction. The ability of this study to detect such effects may partly reflect unflued gas appliance use among this sample.

Age Factors↗

PubMed2003

Confirmation of Escherichia coli and its distinction from Klebsiella species by gas and indole formation at 44 and 44.5 degrees C.

AIMS: In the enumeration of coliform bacteria, confirmation of Escherichia coli has been based upon gas and indole production at the elevated incubation temperature. The test for gas production has recently been questioned. The aim of this study was to investigate the impact of gas production test on the reliability of confirmation of E. coli. METHODS AND RESULTS: The impact of several media on growth, gas and/or indole formation was tested at 44 and 44.5 degrees C using 547 environmental isolates. These were mainly E. coli, Klebsiella pneumoniae, K. oxytoca and Enterobacter cloacae strains. Another set of 250 faecal and environmental klebsiellae were tested for their maximum temperature for growth (Tmax) and for gas formation. Escherichia coli and even K. pneumoniae grew well in all the media, but gas production was more dependent on the medium used. Growth of the mainly gas negative Ent. cloacae and K. oxytoca strains was still more sensitive to the medium and incubation conditions. Tryptophan salt broth was the most productive medium for the indole test, followed by lauryl tryptose mannitole and tryptone mannitol ricinoleate broth (TRM). Tmax of K. oxytoca was clearly lower than Tmax of K. pneumoniae but a rather high fraction of its isolates produced indole at 44.5 degrees C. CONCLUSIONS: False-positive E. coli confirmation is possible if gas production is not tested for and the confirmation is based on indole test only. SIGNIFICANCE AND IMPACT OF THE STUDY: Erroneous positive results on routine analysis for E. coli can occur.

Bacterial Typing Techniques↗

PubMed2002

Investigating the prebiotic and gas-generating effects of selected carbohydrates on the human colonic microflora.

AIMS: To compare the fermentation of dietary carbohydrates with reference to their prebiotic and gas-generating capacity. METHODS AND RESULTS: Static anaerobic batch culture fermentations were carried out measuring gas generation and the prebiotic effect of five selected substrates (including various fructo-oligosaccharides, levan and maltodextrin). The largest gas producer was levan, whilst those showing no significant difference to Actilight included oligofructose and maltodextrin. Gas composition data showed that hydrogen and carbon dioxide were the two most quantitatively important gases. The substrate that appeared to have the best prebiotic effect in vitro was branched chain fructo-oligosaccharide (FOS), followed by oligofructose, Actilight and maltodextrin which each exerted a similar effect. The substrate with the least bifidogenic effect was levan. CONCLUSIONS: The composition and total gas generation data showed that there was much variation between and within donor inocula. Generally, the lower gas producers had a more selective fermentation whilst larger gas producers were less specific. SIGNIFICANCE AND IMPACT OF THE STUDY: The study of these three parameters enabled a more complete picture of carbohydrate breakdown to be drawn and hence highlighted the need for potential prebiotics to be more extensively evaluated in order to reduce negative side-effects such as gas distension.

Bacteria↗

PubMed1990

[The expanding gas operation after a 15-year use. Animal experiment studies, subsequent developments of the method and clinical results in the treatment of ablatio retinae].

The expanding-gas-operation, a detachment surgery consisting in an intraocular (i.o.) injection of an expanding gas such as SF6 (without drainage and without vitrectomy) in combination with cryo or laser, was described by Kreissig in 1979. The method was used in the treatment of tears problematic for tamponading by extraocular (e.o.) plombages (giant tear, hole in posterior pole, scattered groups of breaks). With the introduction of the perfluorocarbon gases (CF4, C2F6, C3F8, C4F10) by Lincoff and his group in the beginning of the eighties the use of the gas-operation was improved: the expansion of the new gases ranged from 1.9x to 5x and their i.o. duration, defined as half time volume, from 6 to 45 days. However, animal experiments confirmed that an expanding i.o. gas bubble induces a break-down of the blood aqueous barrier, an increase of protein, an infiltration of cells into the vitreous and a compression of vitreous membranes against the retina implying the threat of subsequent proliferative vitreoretinopathy (PVR). The expanding-gas-operation is contraindicated in a detachment with PVR stage C and D. In spite of a recent renaissance of the expanding-gas-operation by Dominguez and Hilton in the middle of the eighties, the issue is still valid: in the treatment of a detachment an e.o. plombage is better than an i.o. gas bubble; this is especially pertinent for uncomplicated retinal detachments representing the indication of choice for a temporary e.o. plombage without drainage, the balloon-operation. As a consequence, at present the expanding-gas-operation is only justified for problematic retinal tears.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1978

Observational model of the ionized gas in Seyfert and radio-galaxy nuclei.

Equivalent widths of the total emission-line Hbeta in Seyfert 1, Seyfert 2, and intermediate-type Seyfert galaxies, expressed in terms of the featureless continuum, all have approximately the same frequency distribution. This suggests that the energy-input mechanism to both the narrow-line, low-density gas and the broad-line, high-density gas is photoionization by the featureless continuum. The reason for the weakness of the narrow emission lines in extreme Seyfert 1 galaxies is then the absorption of most of the ionizing photons in the dense gas near the central source. The statistics of line widths can be fitted by a model in which the dense gas has typical rotational velocity 5000 km/sec and typical turbulent velocity 2000 km/sec. A model is proposed in which the dense gas forms a rotating, turbulent disk with dimension approximately 0.1 pc and height/diameter approximately 2/5. Seyfert 2 galaxies are objects with little dense gas, and intermediate-type Seyfert galaxies are objects in which the dense gas is optically thin to ionizing radiation at least along the poles. Most radio galaxies have strong narrow emission lines, suggesting that escape of radio plasma can only occur where some ionizing photons can also escape from the dense gas. Other predictions, implications, and tests of this model are discussed.

Journal Article↗

PubMed2001

A characterization of solution gas flaring in Alberta.

Information reported here is the result of a detailed analysis of data on flared and vented solution gas in the Province of Alberta in 1999. A goal of characterizing these flares was to aid in the improved management of solution gas flaring. In total, 4499 oil and bitumen batteries reported flaring or venting with a combined gas volume of 1.42 billion m3. There was significant site-to-site variation in volumes of gas flared or vented, gas composition, and flare design. Approximately 5% of physical batteries generate 35.7% of the gas flared and vented from oil and bitumen batteries. Therefore, if one were to attempt to mitigate flaring, significant progress could be made by starting with only the largest sites. The monthly variability of gas volumes was considered because high variability could affect implementation of alternative technologies. It was found that slightly more than 40% of the sites were reasonably steady and had monthly deviations of 100% or less from the average flared volume. The variability in monthly volumes was less for the larger batteries. Data from individual well sites show significant variability in the relative concentrations of each of the major species contained in solution gas.

Air Pollution↗

PubMedDate not supplied

Is there a significant gas exchange through the skin of the shrew Crocidura russula monacha?

Because of its small body mass, the shrew Crocidura russula monacha has a relatively high surface area to volume ratio, thin skin, and high thermal conductance compared with larger mammals. This study was aimed at examining the possibility that such a mammal may exhibit a significant skin gas exchange. Gas composition was measured in subcutaneous gas pockets. CO2 and O2 exchange through skin were measured both in vitro and in vivo. In 7-wk-old gas pockets, the steady-state PO2 and PCO2 values were 50 Torr (where 1 Torr = 133.322 Pa) and 35 Torr, respectively, compared with PO2 and Pco2 values of 73 Torr and 33 Torr, respectively, in 1-wk-old gas pockets. These changes are attributed to an increased capillary density and a decreased skin thickness after 7 wk. There was no significant gas exchange through skin during in vitro measurements. In vivo measurements indicated that O2 uptake was 0.5% and CO2 loss was 0.9% of total body metabolism at 20 degrees C. At 35 degrees C, skin O2 uptake and CO2 loss increased to 1.3% and 2.9%, respectively. These values are only part of the expected skin metabolism; thus, the rest must come from blood. Because gas exchange through the skin of this shrew is within the range of other mammals, the relatively low PCO2 and high PO2 in the gas pockets is better explained by the relative hyperventilation state exhibited by this shrew.

Animals↗

PubMed1987

Derivation of VA/Q distribution from blood-gas tensions.

Gas exchange was modelled by a Fortran program. Arterial blood-gas tensions have higher resolution than inert gas retentions in terms of distinguishing a single VA/Q compartment from a progressively broadening lognormal distribution. The maximum number of compartments determinable by arterial blood-gas tensions is three; VA/Q distributions containing more compartments are non-unique. Without utilizing 100% inspired oxygen, arterial blood-gas tensions cannot resolve the relative perfusion in shunt and low-VA/Q compartments, but the total perfusion in these compartments is determinable. The way in which the arterial blood-gas tensions vary with the variables of two and three-compartment distributions is described. Two- and three-compartment VA/Q distributions are derivable from either arterial blood-gas tensions or inert gas retentions.

Algorithms↗

PubMed2005

Lateral gas diffusion inside leaves.

Diffusion of CO2 inside leaves is generally regarded to be from the substomatal cavities to the assimilating tissues, i.e. in the vertical direction of the leaf blades. However, lateral gas diffusion within intercellular air spaces may be much more effective than hitherto considered. In a previous work it was demonstrated that, when 'clamp-on' leaf chambers are used, leaf internal 'CO2 leakage' beyond the leaf chamber gaskets may seriously affect gas exchange measurement. This effect has been used in the present paper to quantify gas conductance (g(leaf,l), mmol m(-2) s(-1)) in the lateral directions within leaves and significant differences between homo- and heterobaric leaves were observed. For the homobaric leaves, lateral gas conductance measured over a distance of 6 or 8 mm (the widths of the chamber gaskets) was 2-20% of vertical conductance taken from published data measured over much smaller distances of 108-280 microm (the thickness of the leaves). The specific internal gas diffusion properties of the leaves have been characterized by gas conductivities (g*(leaf), micromol m(-1) s(-1)). Gas conductivities in the lateral directions of heterobaric leaves were found to be small but not zero. In homobaric leaves, they were between 67 and 209 micromol m(-1) s(-1) and thus even larger than those in the vertical direction of the leaf blades (between 15 and 78 micromol m(-1) s(-1)). The potential implications for experimentalists performing gas exchange measurements are discussed.

Carbon Dioxide↗

PubMed1994

In vivo footprinting of the IRF-1 promoter: inducible occupation of a GAS element next to a persistent structural alteration of the DNA.

GAS (gamma activated sequence) and GAS-like elements are found in a rapidly growing number of genes. Data from EMSA (electromobility shift assay) and transient transfection assays using heterologous promoter systems do not necessarily reflect transcriptional involvement and protein occupation of a binding site in vivo. This has been shown recently by in vivo footprinting of the NF-kappa B site at -40 in the interferon regulatory factor-1 (IRF-1) promoter. Here we show by in vivo footprinting using dimethylsulfate (DMS) that the GAS of the IRF-1 promoter, which also contains an overlapping putative NF-kappa B site, is occupied upon treatment with gamma-interferon (IFN gamma) but not with phorbol 12-myristate 13-acetate (PMA). Irrespective of induction, we detect a very strong DMS hypersensitivity at a guanosine just adjacent to GAS and a less persistent minor DMS hypersensitivity at a central cytosine. Our data confirm the crucial role of GAS in transcriptional activation by IFN gamma and are consistent with induced binding of p91 to GAS. In addition, our data suggest a major conformational distortion of the DNA at the GAS element of the IRF-1 promoter and that this GAS element is not involved in transcriptional activation by PMA.

Base Sequence↗

PubMed1997

Adverse anesthetic outcomes arising from gas delivery equipment: a closed claims analysis.

BACKGROUND: Anesthesia gas delivery equipment is a potentially important source of patient injury. To better define the contribution of gas delivery equipment to professional liability in anesthesia, the authors conducted an in-depth analysis of cases from the database of the American Society of Anesthesiologists Closed Claims Project. METHODS: The database of the Closed Claims Project is composed of closed US malpractice claims that have been collected in a standardized manner. All claims resulting from the use of gas delivery equipment were reviewed for recurrent patterns of injury. RESULTS: Gas delivery equipment was associated with 72 (2%) of 3,791 claims in the database. Death and permanent brain damage accounted for almost all adverse outcomes (n = 55, 76%). Equipment misuse was defined as fault or human error associated with the preparation, maintenance, or deployment of a medical device. Equipment failure was defined as unexpected malfunction of a medical device, despite routine maintenance and previous uneventful use. Misuse of equipment (n = 54, 75%) was three times more common than equipment failure (n = 17, 24%). Misconnects and disconnects of the breathing circuit made the largest contribution to injury (n = 25, 35%). Reviewers judged that 38 of 72 claims (53%) could have been prevented by pulse oximetry, capnography, or a combination of these two monitors. Overall, 56 of 72 gas delivery claims (78%) were deemed preventable with the use or better use of monitors. The year of occurrence for claims involving gas delivery equipment ranged from 1962 to 1991 and did not differ significantly from claims involving other adverse respiratory events. CONCLUSIONS: Claims associated with gas delivery equipment are infrequent but severe and continue to occur in the 1990s. Educational and preventive strategies that focus on equipment misuse and breathing circuit configuration may have the greatest potential for enhancing the safety of anesthesia gas delivery equipment.

Anesthesiology↗

PubMedDate not supplied

Platelet and neutrophil distributions in pump oxygenator circuits. III. Influence of nitric oxide gas infusion.

The authors used quantitative gamma scintigraphy to evaluate the influence of nitric oxide gas on platelet and neutrophil deposition in Cobe Duo microporous oxygenators during cardiopulmonary bypass (CPB). The effects of nitric oxide gas on circulating platelet and neutrophil counts and platelet function also were assessed. Animals were prepared by standard methods. Cells were harvested, labeled (111 In platelet and 99mTc neutrophil), infused, and recirculated. Nitric oxide gas, a guanylate cyclase pathway promoter, was infused int he Duo gas port at 500 ppm (t = 0-60 min), increased to 1,000 (t = 60-80 min), and stopped (final, 10 min). Images were taken at 10-15 min intervals during CPB. Standard isotope image corrections were made. No differences between nitric oxide gas and control experiments were observed for flow, pressure, hematocrit, or replacement volume. Nitric oxide gas infusion significantly (p < 0.05) reduced both platelet adherence to the oxygenator and in vitro platelet aggregation. Neutrophil adhesion tended to be lower, and circulating platelet and neutrophil counts tended to be higher with nitric oxide gas infusion. Results of in vitro aggregometry studies using rabbit platelets indicate that the class V phosphodiesterase inhibitor zaprinast can strongly enhance the inhibitory effects of nitric oxide. The authors conclude nitric oxide gas is a promising platelet sparing agent in the setting of CPB.

Animals↗

PubMed1991

Is neonatal inspired gas humidity accurately controlled by humidifier temperature?

OBJECTIVE: To investigate: a) the relationship between humidifier temperature and inspired gas humidity and b) the effect of insulating the inspiratory tube on "rainout" (condensate). DESIGN: Observational study. SETTING: Regional neonatal unit in a university hospital. PATIENTS: Forty-eight infants receiving assisted ventilation, of whom 31 infants were nursed in incubators and 17 under radiant heaters. MEASUREMENTS AND MAIN RESULTS: Despite always maintaining humidifier temperature greater than 34.7 degrees C, inspired gas humidity decreased below the American National Standards Institution minimum of 30 mg H2O/L on 35 of 479 occasions. At a humidifier temperature of 36 degrees C, inspired gas humidity varied between 17 and 43 mg H2O/L. In incubators set at a temperature of 34.1 +/- 1.3 (SD) degrees C, inspired gas humidity was linearly related to humidifier temperature, but with wide scatter (p less than .001, r2 = .28). In cooler incubators set at 32.9 +/- 1.8 degrees C, inspired gas humidity varied inversely with humidifier temperature. This variation was attributed to condensate due to inspired gas cooling within the incubator. Insulation of the inspiratory tubing reduced condensate by only 15%. CONCLUSIONS: Inspired gas humidity cannot be predicted reliably from humidifier temperature. Accurate control will require a new generation of humidifiers that measure inspired gas humidity.

Equipment Design↗

PubMed2000

Comparison of the response of saline tonometry and an automated gas tonometry device to a change in CO2.

OBJECTIVE: To examine the speed of response of saline tonometry and an automated gas tonometry system by using standard tonometry catheters. DESIGN: In vitro validation study. SETTING: Experimental research laboratory. INTERVENTIONS: Tonometry catheters were placed in a test chamber designed to simulate the lumen of a hollow viscus and were exposed to a rapid change in CO2 from 0% to 5% or 10%. Measured CO2 over time was fit to a mathematical model to determine the response time constant (the time to reach 63% of the final value) for each system. MEASUREMENTS AND MAIN RESULTS: Response time to a change in CO2 was significantly faster with the automated gas system than with traditional saline tonometry. The mathematical time constant for a 5% change in CO2 in a gas environment was 2.8 mins (95% confidence interval, 2.6-3.0 mins) for the gas and 6.3 mins (95% confidence interval, 5.8-7.3 mins) for the saline technique. These times were longer for the CO2 change in a liquid environment: The time constant was 4.6 mins (95% confidence interval, 4.5-4.7 mins) for the gas system and 7.8 mins (95% confidence interval, 7.15-8.6 mins) for the saline tonometry. There was a significantly lower final equilibration value for the CO2 measurement with saline tonometry. There was essentially no difference in time constants for each system for a 5% change compared with a 10% CO2 change, except for a slightly faster time constant for the gas tonometry system with a 5% change in the gas environment (5%: 2.8 mins vs. 10%: 3.3 mins). CONCLUSIONS: The automated gas tonometry system has a significantly faster response to a change in CO2 than conventional saline tonometry.

Carbon Dioxide↗

PubMed2002

Energy balance in the intubated human airway is an indicator of optimal gas conditioning.

OBJECTIVE: The optimal level of inspired heat and humidity for patients receiving long-term mechanical ventilation is still the subject of debate. Many laboratory studies examining surrogate markers for optimal humidity suggest that inspired gas should be at body temperature and fully saturated. The aim of this study was to determine the inspired gas condition that was thermodynamically neutral to the airway of intubated patients, and also examine the contribution of the endotracheal tube to airway heat and water balance. DESIGN: Prospective, block-randomized, observational study. SETTING: General adult intensive care unit of a metropolitan teaching hospital. PATIENTS: Ten adult patients requiring intermittent positive pressure ventilation for nonpulmonary reasons. INTERVENTIONS: Each patient was given four different gas conditions--30 degrees C, 30 mg/L; 34 degrees C, 38 mg/L; 37 degrees C, 44 mg/L; and 40 degrees C, 50 mg/L--to breathe in random order. MEASUREMENTS AND MAIN RESULTS: Inspired and expired gas temperature and humidity, and the temperature gradient down the endotracheal tube, were measured and the inspired gas condition that gave thermodynamic neutrality was determined. This was found to be gas at body temperature, saturated. Airway workload and airway water loss increased linearly as the inspired gas departed from this condition, at approximately 1.4 kJ/hr/ degrees C and 0.5 mL/hr/ degrees C, respectively. The endotracheal tube contributed very little to heat and water exchange. CONCLUSIONS: Inspired gas at body temperature and saturated is thermodynamically neutral to the intubated airway, and thus may be considered the optimal condition for ventilation lasting more than a few hours.

Adolescent↗

PubMed1982

Natural history of extraperitoneal gas after renal transplantation: CT demonstration.

The natural history of extraperitoneal gas present in the operative bed was prospectively evaluated with serial computed tomography in 25 renal transplant patients. While 73% (11/15) of patients studied within the first 4 days after drain removal had residual gas in the operative bed, 90% (9/10) of patients examined after the 5th day had no demonstrable gas in the peritransplant area. Of 12 patients with gas present on the initial scans, follow-up studies documented resolution of the gas in 10 with subsequent benign clinical courses. In the remaining two patients, the gas collections increased in volume on serial examinations followed shortly by wound dehiscence. Our data suggest that gas present later than 1 week following drain removal should prompt careful scrutiny and that an increase in the volume of gas collections on serial studies must be considered pathologic. The incidence and significance of peritransplant fluid collections in these patients are also discussed.

Abscess↗