Breath Ethanol Research Articles

Kinetics of ethanol decay in mouth‐ and nose‐exhaled breath measured on‐line by selected ion flow tube mass spectrometry following varying doses of alcohol

A study has been carried out of the decay of ethanol in mouth-exhaled and nose-exhaled breath of two healthy volunteers following the ingestion of various doses of alcohol at different dilutions in water. Concurrent analyses of sequential single breath exhalations from the two volunteers were carried out using selected ion flow tube mass spectrometry, SIFT-MS, on-line and in real time continuously over some 200 min following each alcohol dose by simply switching sampling between the two volunteers. Thus, the time interval between breath exhalations was only a few minutes, and this results in well-defined decay curves. Inspection of the mouth-exhaled and nose-exhaled breath data shows that mouth contamination of ethanol diminished to insignificant levels after a few minutes. The detailed results of the analyses of nose-exhaled breath show that the peak levels and the decay rates of breath ethanol are dependent on the ethanol dose and the volume of ethanol/water mixture ingested. From these data, both the efficiency of the first-pass metabolism of ethanol and the indications of gastric emptying rates at the various doses and ingested volumes have been obtained for the two volunteers. Additionally and simultaneously, acetaldehyde, acetic acid and acetone were measured in each single breath exhalation. Acetaldehyde, the primary product of ethanol metabolism, is seen to track the breath ethanol. Acetic acid, a possible secondary product of this metabolism, was detected in the exhaled breath, but was shown to largely originate in the oral cavity. Breath acetone was seen to increase over the long period of measurement due to the depletion of nutrients.

Methanol Levels in Saliva--A Non-Invasive Parameter That May Be Useful in Detection of Alcohol Intoxication

Non-invasive screening parameters proving alcohol intoxication are necessary especially in forensic contexts. Results obtained by common measurement methods like the ethanol breath analyzer may be falsified by several parameters like hypoventilation. Therefore, we undertook a pilot study investigating the usefulness and applicability of methanol levels measured in saliva. Our results show that methanol levels in saliva are closely linked to ethanol levels in saliva (r = 0.971, P < 0.0001, t = 5.622, P = 0.000) as well as to ethanol levels in serum (r = 0.786, P = 0.001, t = -1.106, P = 0.058). Therefore, methanol levels measured in saliva might be applicable in order to increase the validity of other non-invasive measurement methods like the ethanol breath analyzer.

Breath Alcohol Analyzer Mistakes Methanol Poisoning for Alcohol Intoxication

Breath alcohol analyzers are used to detect ethanol in motorists and others suspected of public intoxication. One concern is their ability to detect interfering substances that may falsely increase the ethanol reading. A 47-year-old-man was found in a public park, acting intoxicated. A breath analyzer test (Intoxilyzer 5000EN) measured 0.288 g/210 L breath ethanol, without an interferent noted. In the emergency department, the patient admitted to drinking HEET Gas-Line antifreeze, which contains 99% methanol. Two to three hours after ingestion, serum and urine toxicology screen results were negative for ethanol and multiple other substances. His serum methanol concentration was 589 mg/dL, serum osmolality 503 mOsm/kg, osmolar gap 193 mOsm/kg, and anion gap 17 mmol/L. The patient was treated with intravenous ethanol, fomepizole, and hemodialysis without complication. This is a unique clinical case of a breath alcohol analyzer reporting methanol as ethanol. Intoxilyzer devices have been shown to indicate some substances (acetone) as interferents in humans but not methanol. Increased serum concentrations of methanol can be reported as ethanol by a commonly used breath alcohol analyzer, which can result in a delayed diagnosis or misdiagnosis and subsequent methanol toxicity if antidotal treatment is not administered in a timely manner.

Analytical Methods for Breath Investigation

Breath analysis is a non-invasive, painless and attractive diagnostic method without risk to the patients. It has been recommended as a convenient and complementary method for blood and urine analysis. Despite the advantages, breath analysis has not been introduced to medical diagnosis. Only few specific breath tests are available: ethanol in breath after alcohol ingestion, detection of 13CO2 for diagnosis of H. pylori, NO test for evaluation of asthma and capnography, which is commonly used in intensive care and anesthesia. However, there has been an increase, notice in the interest of exhaled breath analysis, especially for the purpose of early cancer diagnosis. It is mainly the result of chromatographic methods development, which has been achieved in the last twenty years. The up-to-date methods of separation and detection of volatile organic compounds allow for achieving low detection limits and high precision of measurements. Sample pre-concentration methods, such as solid sorbents combined with thermal desorption or solid phase microextraction, also have significant importance. Great expectations are also connected with the development of techniques allowing on-line monitoring of breath, directly at the patient bed. This review depicts the issues connected with breath analysis. The main focus has been placed on technical and apparatus aspects. Analytical procedures concerning sample taking, Pre-concentration and analytical techniques have been also discussed.

Effect of hydrofluoroalkane–ethanol inhalers on estimated alcohol levels in asthmatic subjects

Inhaled medication administered via a metered dose inhaler (MDI) is often used to treat asthma. Hydrofluoroalkane (HFA) has replaced chlorofluorocarbons (CFC) as the propellant and these new MDI may contain alcohol. This raises concerns that their use may transiently increase breath ethanol concentration (BEC), thereby interfering with random breath testing. It was hypothesized that HFA-ethanol MDI may contribute to raising BEC above the legal limit. The effect of a HFA-ethanol MDI on BEC was compared with that of CFC and placebo MDI and the effect of ingesting a standard amount of alcohol was also investigated. Asthmatic (n = 16) and normal control subjects (n = 15) were recruited for the double-blind, placebo-controlled study. Each subject used the three MDI in random sequence. BEC was measured at baseline and at 2, 5 and 15 min after inhalation of each MDI, using the Lion Alcometer SD-400TM. Spirometry was performed at baseline and 20 min after the last inhalation. An identical procedure was followed after alcohol consumption. Use of the HFA-ethanol MDI resulted in a significant increase in BEC from 0.002 to 0.0138 mg/100 mL (28 mg/100 mL of blood, P = 0.001) in asthmatics, and from 0.001 mg/100 mL to 0.016 mg/100 mL (33 mg/100 mL of blood, P = 0.002) in normal subjects. By 5 min, there were no significant differences in BEC of asthmatics (0.0031 mg/100 mL) and normal subjects (0.003 mg/100 mL), when compared with baseline (P > 0.2). BEC are transiently elevated after inhalation of HFA-ethanol MDI; however, by 5 min, BEC had already returned to baseline levels. Thus the effect of HFA-ethanol MDI on BEC is transient and would be negligible after 5 min.

Physiologically Based Pharmacokinetic (PBPK) Models for Ethanol

Physiologically based pharmacokinetic models have been used to describe the distribution and elimination of ethanol after intravenous administration. These models have been used to estimate the ethanol infusion profile that is sufficient for achieving a prescribed breath ethanol concentration time course in individuals, providing a useful platform for several pharmacokinetic and pharmacodynamic investigations. Mathematical foundations of these models are examined, including the derivation of an explicit set of governing equations in the form of a system of nonlinear ordinary differential equations. These equations can then be used to formulate and refine parameter identification and control strategies. Finally, a framework in which models related to this model can be constructed and analyzed is described.

A sensor system for monitoring the simple gases hydrogen, carbon monoxide, hydrogen sulfide, ammonia and ethanol in exhaled breath

A sensor array system was constructed incorporating electrochemical sensors for hydrogen, carbon monoxide, hydrogen sulfide and ethanol, a ceramic sensor for total volatiles and a dye-based optical ammonia sensor. The system was calibrated using standard gases balanced with dry air. Limit of detection and % relative standard deviation values (n = 10) for the sensors in the array are hydrogen (0.1 ppm, 2.6%), carbon monoxide (0.4 ppm, 2.1%), ethanol (0.5 ppm, 1.5%), hydrogen sulfide (0.1 ppm, 1.5%) and ammonia (0.6 ppm, 10.7%). Humidity effects were assessed by calibrating with humidified standard gases (hydrogen, carbon monoxide) or spiked breath samples in Tedlar bags (hydrogen sulfide, ethanol and ammonia). The calibration data were used to establish a cross-sensitivity matrix. The concentration of breath volatiles was found to be dependent on exhalation rate and exhalation volume. A test protocol based on these data required volunteers to exhale 1 litre of breath at a rate between 7.5 and 17.5 l min−1. Sensor responses were measured for 40 s then purged at 7 l min−1 (150 s). A longitudinal study was undertaken of ten asymptomatic volunteers over a five-day period. Volunteers ate an ad hoc diet, but fasted prior to giving the first breath sample and then gave samples every hour for 8 h. Breath hydrogen levels for volunteers showed large variations within a day and also from day to day. Fasting levels ranged between 0.3 and 34.1 ppm (mean 9.1 ppm). The carbon monoxide levels for non-smokers were between 0.6 and 4.9 ppm (mean 2.1 ppm), whilst for smokers they were between 8.3 and 18.7 ppm (mean 12.8 ppm). The measured levels of other gases on breath were as follows: hydrogen sulfide (0–1.3 ppm, mean 0.33 ppm), ethanol (0–3.9 ppm, mean 0.62 ppm) and ammonia (0–1.3 ppm mean 0.42 ppm). The system was capable of direct quantitative measurements of low concentrations of a range of volatiles on exhaled breath. The measured values for compounds on the breath of asymptomatic volunteers were in broad agreement with quoted literature ranges. The system will now be assessed in a clinical setting.

Influence of weakly bound adduct ions on breath trace gas analysis by selected ion flow tube mass spectrometry (SIFT-MS)

This paper describes how weakly bound adduct ions form when the precursor ions used in selected ion flow mass spectrometry, SIFT-MS, analyses, viz. H 3O +, NO + and O 2 +, associate with the major components of air and exhaled breath, N 2, O 2 and CO 2. These adduct ions, which include H 3O +N 2, H 3O +CO 2, NO +CO 2, O 2 +O 2 and O 2 +CO 2, are clearly seen when dry air containing 5% CO 2 (typical of that in exhaled breath) is analysed using SIFT-MS. These adduct ions must not be misinterpreted as characteristic product ions of trace gases; if so, serious analytical errors can result. However, when exhaled breath is analysed these adduct ions are partly removed by ligand switching reactions with the abundant water molecules and the problems they represent are alleviated. But the small fractions of the adduct ions that remain in the SIFT-MS spectra, and especially when they are isobaric with genuine characteristic product ion of breath trace gases, can result in erroneous quantifications; such is the case for H 3O +N 2 interfering with breath ethanol analysis and H 3O +CO 2 with breath acetaldehyde analysis. However, these difficulties can be overcome when the isobaric adduct ions are properly recognised and excluded from the analyses; then these two important compounds can be properly quantified in breath. The presence of O 2 +CO 2 in the product ion spectra interferes with the analysis of CS 2 present at low levels in exhaled breath. It is likely that similar problems will occur as other trace compounds are detected in exhaled breath when consideration will have to be given to the possibility of overlapping between their characteristic product ions and ions produced by hitherto unknown reactions. Similar problems are evident in other systems; for example, H 3O +CH 4 adduct ions are observed in both SIFT-MS analyses of methane rich mixtures like biologically generated waste gases and in model planetary atmospheres.

Determination of ethanol in breath for legal purposes using a five-filter infrared analyzer: studies on response to volatile interfering substances**This work was presented in part at a joint conference of the International Association of Forensic Toxicologists (TIAFT) and the International Committee on Alcohol Drugs and Traffic Safety (ICADTS) held in Seattle, Washington, 2007. There was no external funding for this

The analysis of ethanol in exhaled breath is widely accepted and used worldwide for legal purposes to gather evidence of alcohol-impaired driving. Most evidential breath-alcohol instruments incorporate infrared (IR) spectroscopy as the analytical principle focusing on C–H or C–O stretching frequencies in ethanol molecules. The instrument approved for legal purposes in Sweden is called Evidenzer and is equipped with five infrared filters of which four are used for identification and quantification of ethanol and the fifth is a reference filter. The response of Evidenzer was tested against 21 volatile organic compounds (VOCs), and the instrument was programmed to deduct any bias caused by these VOCs if present in a sample of breath. If the amount deducted exceeds a certain threshold value, the entire test is aborted. Whenever this happens, the police request a specimen of venous blood for analysis by gas chromatography. Of a total of 24 072 drunken drivers, the evidential breath-alcohol test was aborted on 27 occasions (0.11%) because an interfering substance was present above the critical threshold. The VOCs most commonly identified in blood were acetone, isopropanol and/or methyl ethyl ketone (MEK). Elevated levels of acetone and isopropanol might arise during ketogenesis in people suffering from diabetes, or in those who eat low carbohydrate diets. High concentrations of acetone and MEK are probably caused by people drinking a technical alcohol product (T-Red), which is available in Sweden and is denatured with these agents. This study confirms that relatively few apprehended drivers in Sweden have elevated concentrations of VOCs in breath other than ethanol. Even the aborted breath tests, to a large extent, contained ethanol above the legal limit for driving.

Sugars are complementary resources to ethanol in foods consumed by Egyptian fruit bats

Food resources are complementary for a forager if their contribution to fitness is higher when consumed together than when consumed independently, e.g. ingesting one may reduce the toxic effects of another. The concentration of potentially toxic ethanol, [EtOH], in fleshy fruit increases during ripening and affects food choices by Egyptian fruit bats, becoming deterrent at high concentrations (>/=1%). However, ethanol toxicity is apparently reduced when ingested along with some sugars; more with fructose than with sucrose or glucose. We predicted (1) that ingested ethanol is eliminated faster by bats eating fructose than by bats eating sucrose or glucose, (2) that the marginal value of fructose-containing food (food+fructose) increases with increasing [EtOH] more than the marginal value of sucrose- or glucose-containing food (food+sucrose, food+glucose), and (3) that by increasing [EtOH] the marginal value of food+sucose is incremented more than that of food+glucose. Ethanol in bat breath declined faster after they ate fructose than after eating sucrose or glucose. When food [EtOH] increased, the marginal value of food+fructose increased relative to food+glucose. However, the marginal value of food+sucrose increased with increasing [EtOH] more than food+fructose or food+glucose. Although fructose enhanced the rate at which ethanol declined in Egyptian fruit bat breath more than the other sugars, the bats treated both fructose and sucrose as complementary to ethanol. This suggests that in the wild, the amount of ethanol-containing fruit consumed or rejected by Egyptian fruit bats may be related to the fruit's own sugar content and composition, and/or the near-by availability of other sucrose- and fructose-containing fruits.

Effects of carbon dioxide in breath gas on proton transfer reaction-mass spectrometry (PTR-MS) measurements

PTR-MS is becoming a common method for the analysis of volatile organic compounds (VOCs) in human breath. Breath gas contains substantial and, particularly for bag samples, highly variable concentrations of water vapour (up to ∼6.3%) and carbon dioxide (up to ∼6.5%). The goal of this study was to investigate the effects of carbon dioxide on PTR-MS measurements; such effects can be expected in view of the already well known effects of water vapour. Carbon dioxide caused an increase of the pressure in the PTR-MS drift tube (∼1% increase for 5% CO 2), and this effect was used to assess the CO 2 concentration of breath gas samples along the way with the analysis of VOCs. Carbon dioxide enhanced the concentration ratio of protonated water clusters (H 3O +H 2O) to protonated water (H 3O +) in the drift tube. Using the observed increase, being ∼60% for 5% CO 2, it is estimated that the mobility of water cluster ions in pure CO 2 is almost 65% lower than in air. Carbon dioxide had a significant effect on the mass spectra of the main breath gas components methanol, ethanol, 1-propanol, 2-propanol, acetone, and isoprene. Carbon dioxide caused a small increase (<10% for 5% CO 2) of the normalised main signals for the non-fragmenting molecules methanol and acetone. The increase can be much higher for the fragmenting VOCs (ethanol, propanol, and isoprene) and was, for 5% CO 2, up to ∼60% for ethanol. This effect of CO 2 on fragment patterns is mainly a consequence of the increased abundance of protonated water clusters, which undergo softer reactions with VOCs than the hydronium ions. Breath gas samples stored in Teflon bags lost ∼80% of CO 2 during 3 days, the decrease of VOC signals, however, is mainly attributed to decreasing VOC concentrations and to the loss of humidity from the bags.

The concentration distributions of some metabolites in the exhaled breath of young adults

The concentrations of ammonia, acetone, methanol, ethanol, propanol and hydrogen cyanide have been measured in the exhaled breath of 26 young adults of age 17/18 years, using selected ion flow tube mass spectrometry (SIFT-MS). Thus the concentration distributions have been constructed and are seen to be essentially log normal with median values in parts per billion (ppb), being ammonia, 317; acetone, 363; methanol, 238; ethanol, 104; propanol, 13; hydrogen cyanide (HCN), 8. There is a clear separation in the median breath ethanol levels between those volunteers who had ingested sugary food/drinks (109 ppb) and those who had not (48 ppb). These data are compared with the results of a study of the same breath compounds, excepting HCN, for a similar sized cohort of healthy volunteers within the age range of 20 to 60 years, which shows that the median levels of these compounds are lower in the young adult volunteer cohort. These HCN measurements are the first to be made in the breath of healthy individuals. The potential implications of these combined results for clinical diagnosis are alluded to.

Biomarkers to disclose recent intake of alcohol: potential of 5-hydroxytryptophol glucuronide testing using new direct UPLC-tandem MS and ELISA methods

This study compared two new methods for direct determination of 5-hydroxytryptophol glucuronide (GTOL) in urine, a biomarker for detection of recent alcohol consumption. Urine samples were collected from ten alcoholic patients during recovery from intoxication. A direct injection ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for measurement of the urinary GTOL to 5-hydroxyindoleacetic acid (5-HIAA) ratio, and an ELISA assay for direct measurement of GTOL, were used. Comparison was made with the urinary ethanol and ethyl glucuronide (EtG) concentrations. The breath ethanol concentration on admission ranged between 1.0-3.1 g/l. The UPLC-MS/MS method showed a median detection time of 39 h for an elevated urinary GTOL/5-HIAA ratio, while EtG was detected for a median of 65 h. Determination of GTOL by the ELISA assay showed 87% sensitivity in detecting positive samples at a 44% specificity, as compared with the UPLC-MS/MS method. The lower sensitivity of the urinary GTOL/5-HIAA ratio compared with EtG for recent drinking may be clinically useful, in cases where the EtG test provides an unwanted high sensitivity for intake of only small amounts of alcohol or unintentional ethanol exposure.

Comparison of fluid absorption during transurethral resection of prostate and Holmium-Yag laser enucleation of benign adenoma of prostate using breath ethanol concentration

Objective:We conducted a study to detect, quantify and compare irrigation fluid absorption in transurethral resection of the prostate (TURP) and Holmium laser enucleation of the prostate (HoLEP), using BEC.Materials and Methods:The study included 50 patients of lower urinary tract symptoms, secondary to benign enlargement of prostate. The patients were nonrandomly allocated to undergo TURP and HoLEP. Twenty-six patients underwent TURP and the remaining 24 underwent HoLEP. Sterile water tagged with 1% ethanol w/v was used for irrigation. Absorption was detected and quantified every 10min by BEC levels. Data was analyzed using standard nomograms.Results:In HoLEP, 14/24 had no fluid absorption. The remaining 10/24 showed fluid absorption ranging from 95 ml to 300 ml. In TURP, all had fluid absorption ranging from 250-980 ml. Three TURP patients developed overt symptoms, while none did in the HoLEP group.Conclusions:Fluid absorption observed in our study in the HoLEP group was lower than in the TURP group.

Evaluation of alcohol metabolism in humans using the non‐invasive [13C]‐ethanol breath test – influence of gender, Helicobacter pylori infection and polymorphism of alcohol‐oxidizing enzymes

SummaryBackgroundThe [13C]‐ethanol breath test (EBT) has been proposed as a novel non‐invasive laboratory test to detect the degradation of ethanol into CO2. However, this method has not yet been evaluated clinically.AimTo investigate the factors that influence [13C]‐EBT.MethodsTwenty‐six healthy volunteers were instructed to drink 100 mL of beer (4 g ethanol) containing 100 μL of [13C]‐ethanol. Breath samples were collected every 15 min before and after the intake of ethanol solution and 13CO2‐enrichment was measured using mass spectrometry. CO2 excretion was then calculated, and the results were evaluated using kinetic parameters (Tmax, Cmax, AUC).Results T max (min) was significantly shorter in men than in women but not Cmax and AUC. Infection with H. pylori had no impact on all kinetic parameters. Genetic alcohol dehydrogenase (ADH) polymorphisms did not affect 13CO2 excretion, but Cmax (11.1 ± 3.4% dose/h, n = 16) and AUC (10.5 ± 3.4% dose) were slightly increased in aldehyde dehydrogenase (ALDH)‐deficient individuals (heterozygote of ALDH2*2) (13.2 ± 3.2 and 12.9 ± 4.5, respectively; n = 10).Conclusions[13C]‐EBT is capable of assessing the metabolic processing of 100 mL beer in a non‐invasive way. Kinetic parameters are partially influenced by ALDH polymorphism but not by gender, H. pylori infection or ADH polymorphism.

False-positive breath-alcohol test after a ketogenic diet

A 59-year-old man undergoing weight loss with very low calorie diets (VLCD) attempted to drive a car, which was fitted with an alcohol ignition interlock device, but the vehicle failed to start. Because the man was a teetotaller, he was surprised and upset by this result. VLCD treatment leads to ketonemia with high concentrations of acetone, acetoacetate and beta-hydroxybutyrate in the blood. The interlock device determines alcohol (ethanol) in breath by electrochemical oxidation, but acetone does not undergo oxidation with this detector. However, under certain circumstances acetone is reduced in the body to isopropanol by hepatic alcohol dehydrogenase (ADH). The ignition interlock device responds to other alcohols (e.g. methanol, n-propanol and isopropanol), which therefore explains the false-positive result. This 'side effect' of ketogenic diets needs further discussion by authorities when people engaged in safety-sensitive work (e.g. bus drivers and airline pilots) submit to random breath-alcohol tests.

Evaluation of alcohol metabolism in humans using the non‐invasive [13C]‐ethanol breath test – influence of gender, Helicobacter pylori infection and polymorphism of alcohol‐oxidizing enzymes

SummaryBackgroundThe [13C]‐ethanol breath test (EBT) has been proposed as a novel non‐invasive laboratory test to detect the degradation of ethanol into CO2. However, this method has not yet been evaluated clinically.AimTo investigate the factors that influence [13C]‐EBT.MethodsTwenty‐six healthy volunteers were instructed to drink 100 mL of beer (4 g ethanol) containing 100 μL of [13C]‐ethanol. Breath samples were collected every 15 min before and after the intake of ethanol solution and 13CO2‐enrichment was measured using mass spectrometry. CO2 excretion was then calculated, and the results were evaluated using kinetic parameters (Tmax, Cmax, AUC).Results T max (min) was significantly shorter in men than in women but not Cmax and AUC. Infection with H. pylori had no impact on all kinetic parameters. Genetic alcohol dehydrogenase (ADH) polymorphisms did not affect 13CO2 excretion, but Cmax (11.1 ± 3.4% dose/h, n = 16) and AUC (10.5 ± 3.4% dose) were slightly increased in aldehyde dehydrogenase (ALDH)‐deficient individuals (heterozygote of ALDH2*2) (13.2 ± 3.2 and 12.9 ± 4.5, respectively; n = 10).Conclusions[13C]‐EBT is capable of assessing the metabolic processing of 100 mL beer in a non‐invasive way. Kinetic parameters are partially influenced by ALDH polymorphism but not by gender, H. pylori infection or ADH polymorphism.

A longitudinal study of methanol in the exhaled breath of 30 healthy volunteers using selected ion flow tube mass spectrometry, SIFT-MS

Selected ion flow tube mass spectrometry, SIFT-MS, has been used to monitor the volatile compounds in the exhaled breath of 30 volunteers (19 male, 11 female) over a six-month period. Volunteers provided breath samples each week between 8:45 am and 1 pm (before lunch), and the concentrations of several trace compounds were obtained. In this paper the focus is on methanol in breath. The median methanol level determined using the H3O+ precursor ions for all samples was 461 parts-per-billion (ppb), the concentrations for all the samples ranging from 32 to 1684 ppb. The distribution of breath methanol concentration is seen to be log-normal for this healthy population; the geometric mean was 450 ppb, close to the median value, and the multiplicative (geometric) standard deviation was 1.62. Breath methanol is not correlated with age, breath ethanol or ethanol consumed in the previous 24 h, but there was an inverse correlation with body mass index (BMI) for the cohort of volunteers recruited for this study. Observed breath methanol levels are well compatible with the previously published blood methanol levels. Some tentative suggestions are made concerning the origin of endogenous methanol.

Evaluation of Fluid Absorption During Holmium Laser Enucleation of Prostate by Breath Ethanol Technique

In a prospective manner we studied various factors affecting fluid absorption during HoLEP. We also simultaneously evaluated changes in serum electrolytes and hemoglobin decrease during HoLEP. This prospective study comprised of 53 patients who underwent HoLEP at our institute. Irrigation fluid was normal saline tagged with ethanol (1% w/v). Intraoperatively a standard breath analyzer was used to monitor expired breath ethanol levels during the procedure at 10-minute intervals. Patients who absorbed irrigating fluid as indicated by positive intraoperative breath tests were considered absorbers. Serum electrolyte and hemoglobin estimations were done before and after surgery. Total irrigation time, amount of irrigation fluid used, weight of resected tissue and presence of capsular perforation were recorded. Statistical analysis was performed to observe the effects of various factors on the amount of intraoperative fluid absorption. Of 53 patients studied 14 (26.41%) demonstrated fluid absorption in the range of 213 to 930 ml (mean 459). Preoperative prostate weight, total irrigation time, amount of irrigation fluid used and resected tissue weight were all significantly greater in absorbers. Similarly, absorbers had a statistically significant decrease in hemoglobin level postoperatively. There was no statistically significant change in serum electrolytes between absorbers and nonabsorbers. Preoperative weight of prostate, total irrigation time, amount of irrigation fluid used and weight of resected tissue all directly influence the amount of fluid absorption during HoLEP. There is no significant change in serum electrolytes and no risk of the transurethral resection syndrome.

Breath biomarkers and non-alcoholic fatty liver disease: Preliminary observations

Breath biomarkers have the potential to offer information that is similar to conventional clinical tests or they are entirely unique. Preliminary data support the use of breath biomarkers in the study of liver disease, in particular non-alcoholic fatty liver disease (NAFLD). It was evaluated whether breath ethanol, ethane, sulfur compounds and acetone would be associated with hepatic histopathology amongst morbidly obese patients presenting for bariatric surgery. Breath samples were collected during a preoperative visit and compared with liver biopsies obtained during the surgery. A Student's two-tailed t-test was used to compare differences between the two groups. Linear regression was used to analyse associations between the concentrations of breath molecules and independent predictor variables. It was found that breath ethanol, ethane and acetone can be useful biomarkers in patients with NAFLD. In particular, breath ethanol can be associated with hepatic steatosis, and breath acetone can be associated with non-alcoholic steatohepatitis.