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Biomedical subjects

R G Hahn

Publications and source records attributed to R G Hahn.

At least 91 records · Page 5Linked to original sources
PubMed1997

Concentration-time profiles of ethanol in arterial and venous blood and end-expired breath during and after intravenous infusion.

Ethanol (0.40 g/kg) was administered to 13 healthy men by intravenous (i.v.) infusion at a constant rate for 30 min. The concentrations of ethanol in arterial blood (ABAC), venous blood (VBAC), and end-expired breath (BrAC) were measured at 17 exactly timed intervals. Blood-ethanol was determined by headspace gas chromatography and breath-ethanol was measured with a quantitative infrared analyzer (DataMaster). BrAC was multiplied by 2300 to estimate the concentrations of alcohol in blood. During the infusion of ethanol, ABAC exceeded VBAC by about 10 mg/dL on the average and ABAC was also higher than BrAC x 2300 by about 4 mg/dL on average. When infusion of alcohol ended, ABAC, VBAC, and BrAC were 94.8 +/- 2.06 (+/- SE), 84.7 +/- 1.54, and 89.3 +/- 2.10 mg/dL, respectively. The concentrations of alcohol in blood (ABAC and VBAC) and breath decreased abruptly after the administration of alcohol stopped and by 5 min postinfusion, the A-V differences in concentration of ethanol were small or negligible. The mean apparent half-life of the distribution plunge was 7 to 8 min, being about the same for ABAC, VBAC, and BrAC. The disappearance rate of ethanol was 15.5 +/- 0.55 mg/ dL/h (mean +/- SE) for arterial blood, 15.2 +/- 0.49 mg/dL/h for venous blood, and 16.3 +/- 0.73 mg/230 L/h for breath; no significant differences were noted (p > 0.05). We conclude that A-V differences in the concentration of ethanol exist during the loading phase but are rapidly abolished when the administration of ethanol terminates. In the post-absorptive phase of ethanol kinetics, when alcohol has mixed with the total body water, VBAC exceeds ABAC by about 1-2 mg/100 mL on average.

Adult↗
PubMed1996

Total fluid balance during transurethral resection of the prostate.

All fluids given and recovered during and for 24 hours following transurethral resections of the prostate (TURP) in 35 elderly men were recorded and compared with the health status of the patient. The results show that irrigating fluid absorption and the choice of a crystalloid or a colloid solution for intravenous fluid supplementation were the most important factors governing the total fluid balance at the end of TURP as well as 2 hours later. At 24 hours after the operation, the absorption of irrigating fluid during TURP and the presence of cardiac disease promoted retention of fluid. Impaired kidney function and serum cortisol concentration did not, however, correlate with the fluid balance.

Aged↗
PubMed1996

Survival after high-dose intravenous infusion of irrigating fluids in the mouse.

OBJECTIVES: Fluid absorption is still a potentially fatal complication in patients undergoing transurethral resection of the prostate. We induced experimental overhydration in animals to find out which of three widely used irrigating fluids is most strongly associated with survival. METHODS: The survival and incidence of voiding was studied in 120 mice after an intravenous infusion of either 225, 250, 275, or 300 mL/kg of glycine 1.5%, mannitol 5%, or sorbitol 2% plus mannitol 1% over 60 minutes. RESULTS: Only 20% of the animals survived the glycine solution, whereas the overall survival rate after mannitol was 60%. The corresponding figure for sorbitol plus mannitol was 32%. Logistic regression analysis showed that survival was significantly more likely after infusion of mannitol 5% compared with the other irrigating fluids. The likelihood of survival was also higher in the animals in which the infusion induced diuresis and when the smaller volumes of irrigating fluid were given. CONCLUSIONS: Mannitol 5% offered the best chance of survival.

Animals↗
PubMed1996

Complications during transurethral vaporization of the prostate.

OBJECTIVES: To review adverse events during transurethral vaporization of the prostate (TVP) and to compare them with those occurring during transurethral resection of the prostate (TURP). METHODS: One experienced surgeon performed 26 consecutive TVPs and 100 TURPs. We monitored blood loss by photometry, fluid absorption by the ethanol method, and hemodynamic stability with a blood pressure manometer. RESULTS: Total blood loss and the rate of blood loss were significantly lower during TVP. Fluid absorption occurred during most TVPs, but it was mostly small volumes. No sudden drop in arterial pressure was recorded during TVP, but this did occur in 11% of the TURPs. Complications that would normally require medical attention (blood loss greater than 800 mL, fluid absorption greater than 500 mL, or hemodynamic instability) were more infrequent during TVP than during TURP (P = 0.012). CONCLUSIONS: Transurethral vaporization of the prostate was associated with fewer intraoperative complications than was TURP.

Aged↗
PubMed1996

Ethanol monitoring of the transurethral resection syndrome.

Ethanol monitoring is a fairly new method of assessing fluid absorption during transurethral resection of the prostate (TURP). By using an irrigating fluid containing a trace amount of ethanol, the absorption can be measured by expired-breath tests. We describe a TURP in which large-scale absorption of irrigating fluid occurred despite the use of a pressure-warning device set at 10 cm H2O. The surgeon decided to terminate the operation because 1.0 liters of fluid had been absorbed over 10 minutes, and another 1.0 liter was absorbed during the 10 minutes required to conclude the surgery. The high absorption rate suggests that continued resection would have promoted a severe transurethral resection syndrome. This was prevented by the indication given by the breath test, whereas the pressure-warning device failed to do so.

Absorption↗
PubMed1996

'Double toxicity' of glycine solution in the mouse.

OBJECTIVE: To study whether glycine, which may contribute to the symptoms of the transurethral resection syndrome promotes death in a mouse model and whether a modification of the glycine concentration offers a better chance of survival. MATERIALS AND METHODS: Mortality was determined in 120 mice after an intravenous infusion of increasing volumes and concentrations of glycine solution. The animals were divided into groups of 10 and given 150, 180, 200 or 220 mL/kg body weight of 1.1, 1.5 or 2.2% glycine solution. As a control, 220 mL/kg of a 5% mannitol solution was given to 12 mice. RESULTS: After receiving an isosmotic (2.2%) glycine solution 70% of the animals died, while the overall death rate for 1.5% glycine was only 20%. When 1.1% glycine was used, the mortality was 10% after infusion of 150 and 180 mL/kg and 80% after infusion of > or = 200 mL/kg. Logistic regression analysis showed that the outcome for the two highest glycine concentrations was directly related to the dose of glycine and not to the water load. Of 12 mice receiving the isosmotic 5% mannitol solution, three died. CONCLUSIONS: A 1.5% glycine solution offered the best chance of survival. The mortality was governed both by the glycine dose (2.2 and 1.5%) and the tendency of the solution to produce overhydration of the cells (1.1%). Glycine toxicity was most important when small volumes were infused.

Animals↗
PubMed1996

Femoral vein blood flow during transurethral resection of the prostate.

OBJECTIVE: To determine whether bladder distension affects venous haemodynamics during transurethral resection of the prostate (TURP) such that irrigating fluid is more easily absorbed. PATIENTS AND METHODS: The right common femoral vein was examined using an ultrasound Doppler blood-flow scanner in 10 patients (mean age 73 years, range 63-80) undergoing TURP. Measurements of blood flow were performed before, during and after the bladder was filled with irrigating solution. Fluid absorption was measured by the ethanol method. RESULTS: Measurements before, half-way through and immediately after the resection all showed that the luminal diameter and the cross-sectional area of the femoral vein increased significantly when the bladder was filled with irrigating fluid. Furthermore, a decrease in the normal variation of blood flow with breathing often occurred when the bladder was filled, indicating that proximal venous obstruction was the cause of the increase in vessel diameter. However, there was no apparent association between these changes and the absorption of irrigating fluid. CONCLUSIONS: Filling the bladder with irrigating fluid with the patient in the lithotomy position during TURP was followed by signs of iliac venous obstruction but this did not correlate with the absorption of irrigating fluid.

Aged↗
PubMed1996

Haemodynamic effects of irrigating fluids studied by Doppler ultrasonography in volunteers.

OBJECTIVE: To study whether moderate amounts of irrigating fluids induce cardiac stress when infused into healthy volunteers, giving special attention to solutions containing ethanol as a tracer of absorption. SUBJECTS AND METHODS: Over a period of 20 min, 15 mL/kg of glycine (1% or 1.5%) or 3% mannitol (all containing 1% ethanol) or sorbitol 2%-mannitol 1% (with no ethanol) were infused intravenously into 10 healthy male volunteers. The central haemodynamic responses were studied using Doppler ultrasonography. RESULTS: Specific and general haemodynamic responses were observed. After infusing glycine there was a reduction of the heart rate and in cardiac output and an elevation of mean arterial pressure, indicating an increase in systemic resistance. There was no improvement when the glycine content was reduced from 1.5% to 1.0%. Furthermore, infusion of all irrigating fluids was associated with a decrease in cardiac output 30 min after the infusion. Almost identical breath-ethanol curves were obtained with the three fluids containing ethanol and all of them caused slight hypoglycaemia. There was no evidence of ethanol-induced tachycardia. CONCLUSIONS: Irrigating fluids containing glycine and ethanol have a specific haemodynamic effect not occurring with solutions containing mannitol or sorbitol.

Adult↗
PubMed1996

Analysis of ethanol in expired air during low-flow isoflurane anaesthesia.

Monitoring of ethanol concentration in expired air is a method for assessing fluid absorption during transurethral prostatic surgery and endometrial resection, but the validity of this technique has not been studied in low-flow ventilation systems. For this purpose, we have compared the concentration-time profiles of ethanol in expired gas and in venous blood during an i.v. infusion of 0.4 g kg-1 of ethanol over 30 min in 10 women during isoflurane anaesthesia and in the awake state. Anaesthesia increased the ethanol concentration in expired gas by 13% and in venous blood by 34%. The expired gas-blood difference during infusion was abolished, and the central volume of distribution for ethanol was reduced from 20.9 to 8.6 litre, on average. We conclude that breath sampling during low-flow isoflurane anaesthesia reflects an alcohol load well, but that a change in ethanol disposition makes the values slightly higher than in the awake state.

Adult↗
PubMed1996

Time course of increased haemodilution in hypotension induced by extradural anaesthesia.

Volume loading with crystalloid solution results in more pronounced haemodilution in patients who develop arterial hypotension during induction of extradural anaesthesia than in those who remain normotensive. The aim of this study was to describe the time course of this increase in haemodilution. Heart rate, systolic arterial pressure and blood haemoglobin concentration were measured every 3 min during the onset of extradural anaesthesia in 22 elderly men undergoing short urological operations. Fluid therapy consisted of 15 ml/kg body weight of Ringer's acetate solution. Patients with a decrease in systolic pressure of > 25% retained 50% (SD 12%) of the infused fluid in the circulation, while the others retained 36 (8%) (P < 0.002). In both groups, arterial hypotension was followed by increased haemodilution after a delay of as much as 15 min. This suggests that, despite volume loading, there is relative hypovolaemia throughout the development of hypotension.

Adult↗
PubMed1996

Operative factors and the long-term incidence of acute myocardial infarction after transurethral resection of the prostate.

We studied the association between the operative course of transurethral resection of the prostate (TURP) and the morbidity of acute myocardial infarction (AMI) in a cohort comprising 846 patients who underwent this operation between 1983 and 1992. Up to the end of 1993, a total of 69 patients had developed AMI, of which 10 patients had a reinfarction. The relative risk associated with absorption of 500 ml or more of the irrigating medium during surgery was 1.6 [95% confidence interval (CI) = 0.9-3.0] for a first-time AMI after TURP, 6.1 (95% CI = 1.8-20.7) for a reinfarction, and 2.2 (95% CI = 1.3-3.9) for a first-time or a reinfarction combined. A blood loss of 275 ml or more was associated with a decreased relative risk (RR = 0.4; 95% CI = 0.2-0.8) of a first-time AMI after TURP. Patients who lost less than 275 ml of blood and absorbed 500 ml or more of irrigating fluid during surgery had 4.4 times the risk of having an acute myocardial infarction (RR = 4.4; 95% CI = 1.7-11.8). These results appear to indicate that the operative course of TURP is important to the development of AMI over an extended period of time.

Aged↗
PubMed1996

Renal function during intravenous infusion of urological irrigating fluids in the sheep.

BACKGROUND: Oliguria or anuria is an important sign of the transurethral resection syndrome, but the mechanism is not clear. METHODS: We gave an intravenous infusion of 40 ml/kg of glycine 1.5%, sorbitol 2%-mannitol 1%, and isotonic saline (control) in 6 conscious ewes and studied if irrigating fluids cause acute disturbances of kidney function. RESULTS: Both the electrolyte-free solutions induced an increase in urine flow and persistent hypo-osmolality. The renal clearances of p-aminohippuric acid and inulin as well as the unilateral renal blood flow, which was measured via ultrasonic flow probes, increased in response to infusion of glycine but not to sorbitol-mannitol. After the infusions, the renal clearances decreased transiently to below baseline levels. Hypertonic saline was given after half of the infusions of electrolyte-free irrigating fluid. This treatment redistributed water from the cells to the extracellular fluid, but had no effect on renal function. CONCLUSIONS: We conclude that 2500 ml of electrolyte-free irrigating fluid had no detrimental effects on kidney function in sheep. The changes we observed were essentially the same as after infusion of isotonic saline.

Animals↗