Ethanol monitoring of irrigating fluid absorption:

Absorption of irrigation fluid during XPS™ GreenLight laser vaporization of the prostate: results from a prospective breath ethanol monitoring study

PURPOSE

To assess whether and to what extent irrigation fluid absorption occurs during laser vaporization (LV) of the prostate using the 180 W XPS™ GreenLight laser.

METHODS

This prospective investigation was performed in a tertiary care center with a consecutive series of patients undergoing 180 W LV of the prostate. Intraoperative irrigation was performed with isotonic saline containing 1 % ethanol. The volume of irrigation fluid absorption was calculated from periodically performed breath ethanol measurements during LV. Additionally, intraoperative changes in biochemical and hematological blood parameters were assessed.

RESULTS

Positive breath ethanol tests were detectable in 22 of 54 patients. The median absorption volume in these patients was 950 ml (range 208-4579 ml). Ten patients absorbed more than 2000 ml. Absorbers had smaller prostates, more capsular perforations and injuries to venous sinuses, and more total energy was applied with higher output power. Five patients had transient symptoms potentially related to fluid absorption. A significant drop in hemoglobin, hematocrit, venous pH and bicarbonate and an increase in chloride were detectable in the absorber group. These changes were significantly different in the non-absorber group.

CONCLUSIONS

Absorption of irrigation fluid did occur in a relevant proportion of patients undergoing XPS™ GreenLight LV. High-volume absorption (≥2000 ml), which might be clinically relevant, was detectable in almost 20 % of all procedures. Absorption of saline irrigation fluid does not result in a classical TUR syndrome, but fluid and chloride overload can lead to serious complications, particularly in cardiovascular high-risk patients. Thus, patients with symptoms potentially related to fluid absorption should be monitored carefully.

Fluid absorption and the ethanol monitoring method

BACKGROUND

Fluid absorption is a well-known complication of endoscopic surgeries, such as transurethral prostatic resection and transcervical endometrial resection. Absorption of electrolyte-free fluid in excess of 1 L, which occurs in 5% to 10% of the operations, markedly increases the risk of adverse effects from the cardiovascular and neurological systems. Absorption of isotonic saline, which is used with the new bipolar resection technique, will change the scenario of adverse effects in a yet unknown way. Hyponatremia no longer occurs, but marking the saline with ethanol reveals that fluid absorption occurs just as much as with monopolar prostate resections.

METHODS

Ethanol monitoring is a method for non-invasive indication and quantification of fluid absorption that has been well evaluated. By using an irrigating fluid that contains 1% of ethanol, updated information about fluid absorption can be obtained at any time perioperatively by letting the patient breathe into a hand-held alcolmeter.

RESULTS

Regression equations and nomograms with variable complexity are available for estimating how much fluid has been absorbed, both when the alcolmeter is calibrated to show the blood ethanol level and when it is calibrated to show the breath ethanol concentration. Examples of how such estimations should be performed are given in this review article.

CONCLUSIONS

The difficulty is that the anesthesiologist must be aware of how the alcolmeter is calibrated (for blood or breath) and be able to distinguish between the intravascular and extravascular absorption routes, which give rise to different patterns and levels of breath ethanol concentrations.

Is absorption of irrigation fluid a problem in Thulium laser vaporization of the prostate? A prospective investigation using the expired breath ethanol test

BACKGROUND

Benign prostatic hyperplasia (BPH) is a prevalent entity in elderly men. If medical treatment fails, monopolar transurethral resection of the prostate (TUR-P) is still considered as the standard treatment. The proportion of high-risk patients with cardiac comorbidities increases and TUR-P goes along with a relevant perioperative risk. Especially large volume influx of irrigation fluid and transurethral resection syndrome (TUR syndrome) represent serious threats to these patients. Using isotonic saline as irrigation fluid like in transurethral laser vaporization (TUV-P), TUR syndrome can be prevented. However, no prospective trial has ever assessed occurrence or extent of irrigation fluid absorption in Thulium Laser TUV-P.

METHODS/DESIGN

This is a single-center prospective trial, investigating, if absorption of irrigation fluid occurs during Thulium Laser TUV-P by expired breath ethanol test. The expired breath ethanol technique is an established method of investigating intraoperative absorption of irrigation fluid: A tracer amount of ethanol is added to the irrigation fluid and the absorption of irrigation fluid can be calculated by measuring the expiratory ethanol concentrations of the patient with an alcohol breathalyzer. Fifty consecutive patients undergoing TUV-P at our tertiary referral center are included into the trial. Absorption volume of irrigation fluid during Thulium Laser TUV-P is defined as primary endpoint. Pre- to postoperative changes in bladder diaries, biochemical and hematological laboratory findings, duration of operation and standardized questionnaires are assessed as secondary outcome measures.

DISCUSSION

The aim of this study is to assess the safety of Thulium Laser TUV-P in regard to absorption of irrigation fluid.

Absorption of irrigation fluid occurs frequently during high power 532 nm laser vaporization of the prostate

PURPOSE

Absorption of irrigation fluid was not detected during GreenLight™ laser vaporization of the prostate using the first generation 80 W laser. However, data are lacking on intraoperative irrigation fluid absorption using the second generation 120 W high power laser. We assessed whether fluid absorption occurs during high power laser vaporization of the prostate.

MATERIALS AND METHODS

We performed this prospective investigation at a tertiary referral center in patients undergoing 120 W laser vaporization for prostatic bladder outlet obstruction. Normal saline containing 1% ethanol was used for intraoperative irrigation. The expired breath ethanol concentration was measured periodically during the operation using an alcometer. The volume of saline absorption was calculated from these concentrations. Intraoperative changes in hematological and biochemical blood parameters were also recorded.

RESULTS

Of 50 investigated patients 22 (44%) had a positive breath ethanol test. Median absorption volume in the absorber group was 725 ml (range 138 to 3,452). Ten patients absorbed more than 1,000 ml. Absorbers had a smaller prostate, more capsular perforation, higher bleeding intensity and more laser energy applied during the operation. Three patients (13%) had symptoms potentially related to fluid absorption. Hemoglobin, hematocrit and serum chloride were the only blood parameters that changed significantly in the absorber group. The changes were significantly different than those in nonabsorbers.

CONCLUSIONS

Fluid absorption occurs frequently during high power laser vaporization of the prostate. This should be considered in patients who present with cardiopulmonary or neurological symptoms during or after the procedure.

Transurethral resection syndrome in elderly patients: a retrospective observational study

BACKGROUND

Transurethral resection of the prostate (TURP) involves the risk of transurethral resection (TUR) syndrome owing to hyponatremia. Irrigation fluid type, duration of operation, and weight of resected mass have been evaluated as risk factors for TUR syndrome. The purpose of the present study was to identify risk factors related to TUR syndrome in the elderly.

METHODS

After obtaining approval from the Institutional Review Board, data on all elderly males (aged 70 years and older) who underwent TURP under regional anesthesia over a 6-year period at our institution were retrospectively reviewed. TUR syndrome was defined as evidence of a central nervous system disturbance such as nausea, vomiting, restlessness, confusion, or even coma with a circulatory abnormality both intra- and post-operatively. Patients were divided into two groups, positive and negative, for the occurrence of the syndrome. Data such as previous medical history, preoperative and postoperative serum data, weight of resected mass, duration of operation, irrigation fluid drainage technique, anesthetic technique, operative infusion and transfusion volume, and neurological symptoms were collected. Only observational variables with p < 0.05 on univariate analyses were included in the multivariate logistic regression model to ascertain their independent effects on TUR syndrome.

RESULTS

Of the 98 patients studied, 23 had TUR syndrome (23.5%, 95% confidence interval [CI] 14.9-32.0%). Multivariate regression analysis revealed that volume of plasma substitute ≥ 500 ml (odds ratio [OR] 14.7, 95% CI 2.9-74.5), continuous irrigation through a suprapubic cystostomy (OR 4.7, 95% CI 1.3-16.7), and weight of resected mass > 45 g (OR 4.1, 95% CI 1.2-14.7) were associated with significantly increased risks for TUR syndrome (Hosmer-Lemeshow test, p = 0.94, accuracy 84.7%).

CONCLUSIONS

These results suggest that the use of a plasma substitute and continuous irrigation through a suprapubic cystostomy must be avoided during TURP procedures in the elderly.

Prospective evaluation of irrigation fluid absorption during pure transurethral bipolar plasma vaporisation of the prostate using expired-breath ethanol measurements

OBJECTIVES

To investigate if absorption of irrigation fluid occurs during bipolar plasma vaporisation (BPV) of the prostate. To examine the clinical predictors of increased risk of fluid absorption and to assess if changes in serum electrolytes, venous pH, haemoglobin or haematocrit are able to detect intra-operative fluid absorption.

PATIENTS AND METHODS

Over a 15-month period, 55 consecutive patients undergoing BPV of the prostate were investigated. The volume of intra-operative fluid absorption was measured using expired-breath ethanol measurements. Intra-operative irrigation was performed with isotonic saline containing 1% ethanol. The breath ethanol concentration was measured every 10 min during the operation and the volume of irrigation fluid absorption was calculated from these concentrations. Data on clinical (age, prostate volume, smoking status) and surgical variables (operation time, irrigation volume, appearance of capsular perforation) as well as intra-operative changes in serum electrolytes, venous pH, haemoglobin and haematocrit were recorded.

RESULTS

The median (range) age of the patients was 67 (48-87) years and the median (range) prostate volume was 41 (17-111) mL. Nine patients (16%) showed a positive ethanol breath test during the procedure. The median (range) calculated fluid absorption in these patients was 346 (138-2166) mL. Three patients had a fluid absorption >500 mL. One patient with absorption of >2 L showed clinical symptoms (dyspnoea and agitation) during the operation under spinal anaesthesia. In the group of patients with fluid absorption, capsular perforation or injury to larger vessels was more often detectable. In the group of patients with fluid absorption, only venous pH showed a significant change during the operation (from median 7.41 to median 7.34, P = 0.02). The pH decrease was significantly greater in the fluid absorption group than in the group of patients without fluid absorption (0.09 vs. 0.02, P = 0.005).

CONCLUSION

We have demonstrated that significant intra-operative fluid absorption can occur during BPV of the prostate. Care must be taken if using this procedure in patients with significant cardiovascular comorbidities. Respecting the anatomical borders of the prostate seems to play a relevant role in preventing fluid absorption during the procedure. Venous pH could be used to detect potentially dangerous fluid absorption if intra-operative monitoring with breath ethanol measurements is not available.

[Anesthesia in endourological and robot-assisted interventions]

The improved drug therapy leads to increasingly older patients with complex comorbidities in the discipline of operative urology. Today, improved technical equipment provides new operational capabilities in the field of urology. The prone and lithotomy position during surgery leads to physiological changes that affect anesthesia management. The surgical risk of procedures such as transurethral surgery of the prostate or bladder is being altered by laser surgery and other new technologies. Although the incidence of transurethral resection (TUR) syndrome has been reduced in recent years, the intrusion of irrigation fluid still has to be considered during anesthesia. Robot-assisted surgery has successfully completed the experimental stage and is widely used so that new targets have to be challenged. Ureterorenoscopy is performed with flexible, small caliber ureteroscopes which even allow treatment of renal calculi under analgosedation within short time periods. Percutaneous nephrostomy and litholapaxy are still frequently performed in the prone position. With respect to the risks arising from patient positioning, supine or lateral positioning should be considered in individual cases. A good communication between the surgeon and anesthetist allows deviation from daily routine procedures if special indications require a modified approach. In conclusion, a profound knowledge of the (patho-)physiology of general anesthesia and endourological diseases enables anesthetists to provide a prospective type anesthesia, which should prevent the occurrence of life-threatening incidents.

Complications and clinical outcome 18 months after bipolar and monopolar transurethral resection of the prostate

PURPOSE

To compare bipolar resection with the conventional monopolar transurethral resection of the prostate (TURP) with respect to peri- and postoperative complications and long-term outcome.

PATIENTS AND METHODS

Patients with consecutive benign prostatic hyperplasia needing surgery (n=185) from the hospital's waiting list were randomized to TURP using either a bipolar or a monopolar system. Peri- and postoperative parameters were monitored, complications were registered, and timed micturition/International Prostate Symptom Score (TM/IPSS) forms were collected at 3 and 6 weeks and at 6 and 18 months.

RESULTS

Bipolar surgery was followed by a 16% to 20% higher percentage of the patients reporting ongoing improvement (fractional IPSS change >2) at 3 and 6 weeks after the surgery (p<0.05). There were fewer readmissions in the bipolar group than in the monopolar (5 vs. 13, p<0.05). No differences between the groups with respect to hospital stay and catheter duration was recorded. Bipolar and monopolar TURP resulted in marked and sustained improvements of IPSS, bother score, and TM.

CONCLUSIONS

Bipolar TURP, using the transurethral resection in saline (TURis) system, resulted in significantly fewer postoperative readmissions, faster postoperative recovery, and equally long-lasting good results in TM/IPSS and bother score, as in monopolar TURP.

Transient acute liver failure complicating transurethral resection syndrome

Transurethral resection (TUR) syndrome, resulting from dilutional hyponatraemia for excessive absorption of irrigating fluid, represents the most relevant complication of transurethral resection of prostate (TURP). Ethanol is used as a tracer in the irrigant solution to monitor fluid absorption with a breathalyser. An unusual case of transient acute liver failure complicating TUR syndrome is reported. A 54-year-old male patient, without risk factors for the development of toxic hepatitis, was subjected to TURP for treatment of benign prostatic hyperplasia. Fluid absorption (2275 ml), estimated by breathalyser, exceeded maximum allowed absorption (2000 ml) only at the end of the surgical intervention. No signs of possible toxicity were evident in the few hours following the intervention. About 10 h after the end of TURP, the patient developed sweating, vomiting and diarrhoea. Laboratory analysis revealed severe hyponatraemia (116 meq/l) with signs of severe liver impairment (total bilirubin 5.8 mg/dl, alanine aminotransferase 56,500 U/l, aspartate aminotransferase 32,700 U/l), kidney failure (serum creatinine 1.93 mg/dl) and serum ethanol levels of 219 mg/dl (0.2%). The patient was treated with acetylcysteine 150 mg/kg i.v. and furosemide 50 mg i.v. Liver and renal functions improved in few days and recovered completely within 30 days. The TUR syndrome observed in this case was probably extravascular in nature, and could have been identified and prevented by measuring ethanol levels 10 min after ending the surgical procedure. The performance of such a test should be strongly recommended to all surgeons. The clinicians attributed the development of liver impairment in this case to ethanol toxicity. However, further studies are warranted to confirm whether hepatic injury can represent a possible complication of TUR syndrome when ethanol solution is used as irrigant fluid.

Monitoring of fluid absorption with nitrous oxide during transurethral resection of the prostate

BACKGROUND

The fluid absorption that occurs during transurethral resection of the prostate (TURP) can be indicated and quantified by the ethanol method. Recently, nitrous oxide (N(2)O) was tested in animals and volunteers and seemed to be more accurate and safe. The present study compared these two methods in surgical patients.

METHODS

Eighty-six TURPs were performed at two hospitals using an irrigating fluid that contained 3% mannitol, 1% ethanol and 0.004% N(2)O (40 ml/l). The ethanol concentration was measured by end-expiratory tests every 10 min. The N(2)O concentration was measured by a flared nasal cannula every second. Fluid absorption was calculated based on a regression equation (ethanol method) from the area under the curve based on the samples where CO(2) >median (N(2)O method).

RESULTS

Thirteen patients (15%) absorbed >300 ml of fluid as indicated by the ethanol method. The median volume was 707 ml (range 367-1422). Ethanol yielded higher figures for fluid absorption up to 700-800 ml, whereafter the N(2)O method indicated that the absorption was larger. Over the entire range, the mean difference between the two methods at the end of any 10-min period of TURP was only +45 ml, although the 95% limits of agreement were quite separated (-479 to +569 ml).

CONCLUSIONS

The N(2)O method does not require forced breath sampling and was successfully apply clinically. However, there was a dose-dependent difference in result between the ethanol and N(2)O methods, which markedly separated the limits of agreement for a wider range of fluid absorption events.

Parotid area sign: a clinical test for the diagnosis of fluid overload in hysteroscopic surgery

STUDY OBJECTIVE

To describe the clinical test parotid area sign, which is used to assess fluid absorption during resectoscopic surgery and to compare the test with volumetric fluid balance method with respect to its ability to detect fluid overload.

DESIGN

Historical cohort study (Canadian Task Force classification II-1).

SETTING

Tertiary endoscopy center.

PATIENTS

Eighty-six women who underwent resectoscopic surgery between 1999 and 2004 at our center.

INTERVENTION

The volumetric fluid balance method was used to evaluate glycine absorption (glycine deficit) during the surgery. A flexometallic ruler was placed on the left cheek of the patient between 2 fixed points: the midpoint of the philtrum and a point on the mastoid prominence, and this distance (philtrum-mastoid prominence distance) was measured at the beginning of every 3 minutes during, and at the end of the procedure.

MEASUREMENTS AND MAIN RESULTS

Eighty-six patients were divided into 2 groups: Group A, which included patients with absorption less than 1000 mL as measured by the volumetric method; and Group B, which included patients with absorption of 1000 mL or more. The results of the parotid area sign test in the 2 groups were compared. The 2 groups were comparable with respect to the age, weight, preoperative measured philtrum-mastoid prominence distance, and hospital stay. The median (and average absolute deviation) operating time in group A (15 minutes [and 6.79]; range 8-60 minutes; 95% CI of the median, 15-20 minutes) was significantly lower than the median (and average absolute deviation) operating time in group B (25 minutes [and 8.96]; range 9-60 minutes; 95% CI of the median, 20-25 minutes; p <.001). The mean postoperative philtrum-mastoid prominence distance measured in patients of group A (14.23 +/- 0.396 cm [range 14-16 cm, 95% CI 14.10-14.36 cm]) was significantly lower than that in group B [14.76 +/- 0.622 cm (range 14-17 cm, 95% CI 14.58-15.12 cm]; p <.001). By paired t test, the change in the philtrum-mastoid prominence distance after surgery as compared with the value before surgery in each patient was found to be insignificant in group A (p =.86). However, it was found to be significant in group B (p <.001). The increase in the measured philtrum-mastoid prominence distance (i.e., postoperative measurement minus the preoperative measurement) in each patient after surgery was significantly more in group B (mean +/- SD, 0.54 +/- 0.362 cm [range 0-2 cm, 95% CI 0.43-0.65 cm]) than that in group A (mean +/- SD, 0.03 +/- 0.091 cm [range 0-0.4 cm, 95% CI 0.008-0.06 cm]; p <.001). The correlation coefficient for the increase in the philtrum-mastoid prominence distance as the glycine deficit increased in the 2 groups considered together was significant (r = 0.937, p <.01). The partial regression coefficient b value for the effect of duration of surgery while controlling for the effect of fluid deficit was 0.008 (p <.001), and the b value for the effect of fluid deficit while controlling for the effect of duration of surgery was 0.437 (p <.001). The regression coefficient r value (0.727) for the goodness of the fit of the regression line to the data sets was also significant (p <.001). The sensitivity of the test with respect to the volumetric fluid balance is 97.8% (95% CI, 87.28%-99.88%) and specificity is 92.3% (95% CI, 78.03%-97.99%). The negative predictive value is 97.30% (95% CI, 84.19%-99.85%) and positive predictive value is 93.87 (95% CI, 82.13%-98.40%). The conventional positive likelihood ratio for the test is 12.72 (95% CI 4.28-37.77). The conventional negative likelihood ratio is 0.023 (95% CI 0.003-0.16).

CONCLUSION

The parotid area sign is a simple, effective, and easy-to-perform test (in real time continuously) that requires minimal equipment or training. It supplements the volumetric fluid balance method in the detection of fluid overload (1.5% glycine) during resectoscopic surgery. It may also enable us to detect fluid overload when volumetric fluid balance method fails to detect extraneous losses caused by spillage.

Nitrous oxide for monitoring fluid absorption in volunteers †

BACKGROUND

We studied whether nitrous oxide (N(2)O) added to a fluid allows the infused volume to be quantified by measuring N(2)O in the expired air during normal breathing. If so, N(2)O might serve as a tracer of fluid absorption during endoscopic surgery.

METHODS

Twelve male volunteers received continuous and intermittent i.v. infusions (5-45 min) of fluid containing 40 ml litre(-1) of N(2)O. Breath N(2)O and CO(2) concentrations were measured every second via a flared nasal cannula, a standard nasal cannula, or a Hudson mask.

RESULTS

An expression for the amount of infused fluid was obtained by calculating the area under the N(2)O concentration-time curve for samples representative for exhalation (CO(2)>median) and then dividing this area by the median CO(2) for the remaining samples. The N(2)O method then estimated fluid volumes of between 50 and 1400 ml within a 95% prediction interval of +/-200 ml. There were differences of up to 14% in results between the airway devices tested, but the volunteers preferred the flared nasal cannula. N(2)O showed a distinctly higher 3 min variability during intermittent infusion, which could indicate whether fluid absorption is directly intravascular or extravascular. No adverse effects were seen.

CONCLUSIONS

N(2)O method does not require forced end-expiratory breath sampling but still predicts an administered fluid volume with high precision. N(2)O variability can probably be used to distinguish immediately between intravascular and perivesical fluid absorption during surgery.

Fluid absorption in endoscopic surgery

Fluid absorption is an unpredictable complication of endoscopic surgery. Absorption of small amounts of fluid (1-2 litre) occurs in 5-10% of patients undergoing transurethral prostatic resection and results in an easily overlooked mild transurethral resection (TUR) syndrome. Large-scale fluid absorption is rare but leads to symptoms severe enough to require intensive care. Pathophysiological mechanisms consist of pharmacological effects of the irrigant solutes, the volume effect of the irrigant water, dilutional hyponatraemia and brain oedema. Other less widely known factors include absolute losses of sodium by urinary excretion and morphological changes in the heart muscle, both of which promote a hypokinetic circulation. Studies in animals, volunteers and patients show that irrigation with glycine solution should be avoided. Preventive measures, such as low-pressure irrigation, might reduce the extent of fluid absorption but does not eliminate this complication. Monitoring the extent of absorption during surgery allows control of the fluid balance in the individual patient, but such monitoring is not used widely. However, the anaesthetist must be aware of the symptoms and be able to diagnose this complication. Treatment should be based on administration of hypertonic saline rather than on diuretics. New techniques, such as bipolar resectoscopes and vaporizing instead of resecting tissue, result in a continuous change of the prerequisites for fluid absorption and its consequences.

[Anaesthesia and prostate surgery]

OBJECTIVES

To review the current data about anaesthetic management in prostate surgery with special regards on analysis and prevention of specific risks, appropriate anaesthetic procedure keeping with surgery and patient, recognition and treatment of adverse events.

DATA SOURCES AND EXTRACTION

The Pubmed database was searched for articles (1990-2004) combined with references analysis of major articles on the field.

DATA SYNTHESIS

It is strongly recommended to settle germfree urine in the preoperative period. The thromboembolic risk of radical retropubic prostatectomy for cancer parallels lower abdomen oncologic surgery and is prolonged. Preoperative evaluation of cardiovascular, respiratory, neurological and metabolic comorbidity is a source of prognostic information and an essential tool in the management of elderly patients with prostate disease. Extreme patient positioning applied in prostate surgery induces haemodynamic and respiratory changes and are associated with severe muscular and nervous injuries. The laparoscopic access for radical prostatectomy is a growing alternative to the open surgical procedure. Acute normovolaemic haemodilution is a consistent and cost-effective blood conservation strategy in reducing allogenic blood transfusion for radical retropubic prostatectomy. Whether open transvesical or transurethral prostatectomy for treatment of benign hypertrophy depends on the size of the gland: transurethral resection is safe up to 80 g. Intrathecal anaesthesia with a T9 cephalad spread of sensory block, produces adequate conditions for transurethral prostatectomy and allows a rapid diagnosis of irrigating fluid absorption syndrome. In spite of recommended preoperative antibiotic prophylaxis, bacteriemias are frequent during transurethral prostate resection.

Intravesical ethanol test: an ineffective measure of bladder hyperpermeability

OBJECTIVES

To evaluate the intravesical ethanol test as a quantitative measure of bladder hyperpermeability in patients with interstitial cystitis.

METHODS

Patients with a clinical diagnosis of interstitial cystitis and a positive result on the Parsons potassium test were enrolled in the study. The intravesical ethanol test was conducted after completion of the Parsons potassium test. Dose escalation (10% to 20% ethanol) was performed in an attempt to achieve detectable levels of ethanol. Breathalyzer data were recorded in 5-minute intervals for 30 minutes using a calibrated Intox Breathalyzer Model IV Alcosensor. The bladder was then drained, and volume recovered was recorded. The breathalyzer data were recorded for an additional 30 minutes after removal of the catheter at 5-minute intervals.

RESULTS

The 3 patients studied demonstrated significant qualitative evidence of bladder hyperpermeability, with pain and urgency scores ranging from 4 to 5 on the Parsons potassium test. No detectable levels of ethanol were identified in any of the 3 patients after the intravesical ethanol test, with up to 50 mL of 20% ethanol instilled for 30 minutes. Intravesical ethanol instillation was not associated with significant pain or irritative voiding symptoms.

CONCLUSIONS

The intravesical ethanol test did not prove to be a useful clinical adjunct in the diagnosis and management of interstitial cystitis. The evaluation of higher concentrations of ethanol may be warranted.

How to master absorption during transurethral resection of the prostate: basic measures guided by the ethanol method

OBJECTIVE

To evaluate the effect of basic measures to minimize the absorption of irrigating fluid during transurethral resection of the prostate (TURP) to the planned end-point, using the ethanol method to guide the surgeon.

PATIENTS AND METHODS

Forty-six patients underwent TURP with intermittent irrigation using sterile water and 2% ethanol. The ethanol content in the expired breath of the patients was assessed every 5 min using a breath-alcohol monitor. In 25 patients no absorption was indicated but 21 showed some absorption according to the ethanol analyses. The operator was then immediately alerted, paused briefly to determine the route of absorption and to take advantage of blood clots to seal off leakage sites. On resuming the resection, attention was given to the pressure gradients in the operating field, based on bladder compliance and the flow in the irrigating jet. Repeated ethanol analyses were used to assess the result and to guide the surgeon's efforts.

RESULTS

No operation had to be terminated prematurely; the mean absorption in the 21 patients in whom any ethanol was detected was 121 (75-230) mL. In 14 patients absorption occurred once, in six twice and in one there were three small absorption events. The group with absorption did not differ significantly from that with no absorption in operative duration (mean 48 and 47 min), resected weight (mean 32.8 and 31.6 g) or blood loss (mean 550 and 483 mL).

CONCLUSION

If the surgeon is alerted at the first positive ethanol reading, effective measures to minimize absorption can be taken early. Regular use of the ethanol method as an alarm system should permit TURP with a minimum of absorption and avoid an early interruption or premature termination of surgery because of absorption.

Interstitial laser coagulation combined with minimal transurethral resection of the prostate for the treatment of benign prostatic hyperplasia

BACKGROUND

Transurethral resection of the prostate (TURP) represents the gold standard in the surgical treatment of benign prostatic hyperplasia (BPH). However, this method still has significant morbidity mainly associated with irrigation fluid absorption and blood loss.

PATIENTS AND METHODS

A combination of interstitial laser coagulation (ILC) with limited TURP was established to reduce specific risks of transurethral resection and was applied in 41 patients with bladder outlet obstruction caused by BPH. In these patients, a subtotal resection of the prostate was not possible because of anesthesiologic risk factors. After insertion of a suprapubic catheter, ILC was performed under visual control using an Nd:YAG laser followed by resection of the bladder neck or the median lobe. Isotonic carbohydrate solution with 1% ethanol was used for irrigation, and irrigation fluid uptake was quantified by measurements of the ethanol concentration in the patients' exhaled breath. Additional measures such as blood loss, need for blood transfusions, and operative time were evaluated.

RESULTS

The operations were performed without major complications with a mean operative time of 35 +/- 11 minutes for the entire procedure. An irrigation fluid uptake of 9 +/- 32 mL and no TUR syndrome were observed. The mean blood loss was minimal with a change in the hemoglobin of -1.3 +/- 1.1 g/dL and no need for blood transfusions.

CONCLUSION

These results demonstrate that ILC with subsequent minimal TURP is an applicable method in the surgical treatment of BPH with reduction of blood loss and of the risk of TUR syndrome. This procedure may help to reduce the morbidity of TURP, especially in high-risk patients.

Anaesthetic considerations for hysteroscopic surgery

Use of the hysteroscope in modern gynaecological practice continues to develop as a diagnostic and management tool for intrauterine disease. Operative hysteroscopy (OH) is now an accepted alternative to hysterectomy for women with menorrhagia. The advantages of OH are associated with its short operating time, rapid post-operative recovery and low morbidity. However, there are concerns about the potential serious complications which can occur during and following OH, and it is important that both surgeons and anaesthetists are aware of these--especially as many procedures take place as day-cases. Much has been written in the urological literature concerning complications of endoscopic surgery. Information gathered from patients with post-transurethral resection of the prostate (TURP) syndrome has been useful in the treatment of gynaecology patients. However, the techniques used in TURP are not entirely comparable to hysteroscopic surgery as the uterus has a very thick wall, which requires higher distension pressures. The main complications of OH are fluid overload, hyponatraemia, hypo-osmolality, haemorrhage, uterine perforation and, rarely, gas or air embolism. Fluid overload with hyponatraemia and hypo-osmolality occurs in up to 6% of cases and it can be fatal. Therefore, all possible measures should be taken to prevent it or to detect it and treat it early. There are no controlled studies comparing different anaesthetic techniques for OH. Regional anaesthesia may offer an advantage over general anaesthesia because it enables early detection of fluid overload. Great care should be taken when positioning the patient to prevent peripheral neuropathy.

Detecting and quantifying absorbed irrigation fluid by measuring mannitol and sorbitol concentrations in serum samples, and by ethanol monitoring

OBJECTIVE

To describe a modified and improved technique which, in one measurement, estimates the influx of irrigation fluid during endoscopic endometrial ablation or prostate resection, and provides both rapid confirmation of the diagnosis and an estimate of the amount of fluid absorbed by detecting markers which pass from the irrigation fluid to the serum, i.e. mannitol or sorbitol.

PATIENTS AND METHODS

Control samples were taken for analysis before irrigation, and test samples were taken on four occasions during and after intervention, from each of 10 patients undergoing transurethral resection of the prostate. Irrigation fluid was also marked with ethanol (1.5% w/v) and the concentration of this agent measured in the blood and expired air of these patients. The absorbed volume was calculated according to the extracellular distribution space of mannitol.

RESULTS

Mannitol and sorbitol could be measured in 85% and 73% of the 40 test samples, respectively. The threshold for full sensitivity for breath ethanol concentration to detect absorption was 132 mL.

CONCLUSION

This method for detecting serum mannitol and sorbitol represents a valid procedure for confirming and quantifying the absorption of irrigation fluid in the clinic, which agrees closely with the already established ethanol monitoring procedure and which should now be considered as a reference procedure.

Blood loss during transurethral resection of the prostate after 3 months of treatment with finasteride

OBJECTIVES

To study whether pretreatment with finasteride, compared with placebo, reduces the blood loss, operating time, amount of irrigating fluid absorbed, resources used, and other exploratory indexes of extensive surgery during transurethral resection of the prostate (TURP).

METHODS

This double-blind, randomized, placebo-controlled, single-center, 6-month pilot study was designed to study the effects of 3 months of finasteride (5 mg daily) on blood loss during surgery in 60 men who required TURP. The prostate size was measured by transrectal ultrasonography, the surgical blood loss was measured by a HemoCue photometer, and fluid absorption was determined by the ethanol method. The microvessel density was counted using microscopic staining and immunoperoxidase techniques.

RESULTS

Finasteride significantly reduced the prostate size before TURP (P <0.001 versus placebo). No significant between-group differences were found in blood loss (geometric mean 257 and 268 mL for finasteride versus placebo), fluid absorption, operating time, resection weight, or microvessel density. A positive correlation was found between the blood loss and the resection weight. Exploratory analyses indicated that finasteride might reduce the proportion of patients with high blood loss volumes. For prostates with resection weights greater than or equal to the median (18.6 g), finasteride was associated with less blood loss (median 324 mL, n = 14) than in the controls (median 547 mL, n = 14, P <0.01).

CONCLUSIONS

Pretreatment with finasteride may help reduce the blood loss in TURP, except in the smallest resections.

Intravesical ethanol as quantitative measure of bladder hyperpermeability

BACKGROUND AND PURPOSE

Bladder surface hyperpermeability may be a factor in the etiology of interstitial cystitis (IC). We evaluated the intravesical instillation of ethanol as a quantitative measure of bladder hyperpermeability in an experimental model in male New Zealand White rabbits.

MATERIALS AND METHODS

In two study groups (N = 4 each), the glycosaminoglycan (GAG) layer on the bladder surface was disrupted via a 10-minute exposure to 10% protamine sulfate (PS). The study groups then underwent bladder instillation of 10% (group 1) and 20% (group 2) ethanol. The control groups underwent bladder instillation of either 10% (N = 2) or 20% ethanol (N = 2) without exposure to PS. Ten minutes after ethanol instillation, venous blood was sampled, and the ethanol concentration was determined by mass spectrometry. Study group animals were sacrificed after blood sampling. Control animals were sacrificed at 2 weeks and 4 weeks for histologic examination of the bladder.

RESULTS

The blood alcohol concentration was 0 in the control animals exposed to 10% or 20% ethanol, 14.5+/-2.2 ng/dL in the 10% ethanol study group, and 25.6+/-3.6 ng/dL in the 20% ethanol study group. Histologic examination of bladder tissue revealed no ethanol-induced abnormalities in the control animals.

CONCLUSION

Intravesical instillation of 10% and 20% ethanol is a safe and reliable quantitative measure of bladder hyperpermeability in an animal model. Clinical trials are ongoing to evaluate the utility of the intravesical ethanol test for diagnosing IC and monitoring the response to therapy.

The control of haemolysis during transurethral resection of the prostate when water is used for irrigation: monitoring absorption by the ethanol method

OBJECTIVE

To determine whether the addition of ethanol to water for irrigation during transurethral resection of the prostate (TURP) and monitoring breath ethanol could be used to detect irrigant absorption and to limit free plasma haemoglobin in cases of absorption.

PATIENTS AND METHODS

One hundred patients (46 in Piteå, Sweden and 54 in Uong bi, Vietnam) underwent surgery for benign prostatic hyperplasia (BPH) under an intermittent irrigation technique using water containing 2% ethanol. An expired breath alcohol meter was used to monitor ethanol in the patients' breath every 5 min. Blood samples taken after TURP were assessed for free haemoglobin in 99 patients, and other markers of haemolysis were also evaluated in the Swedish group.

RESULTS

Thirty-two patients had detectable ethanol in their breath. There was a close correlation between the maximum ethanol reading during surgery and the level of free plasma haemoglobin after TURP (r = 0.90, P < 0.001). There was no correlation between the duration of TURP and the free haemoglobin level.

CONCLUSION

Monitoring breath ethanol during TURP assesses absorption and so can help to keep control of haemolysis. It is suggested that the value on the alcohol meter should not be allowed to exceed 0.15 (corresponding to a blood ethanol level of 0.15 per thousand), which should maintain the free plasma haemoglobin level at < 1.0 g/L after TURP. Restricting the operative duration per se is not a reliable safety measure.

Intravesical pressure during irrigating fluid absorption in transurethral resection of the prostate

OBJECTIVE

In order to control fluid absorption, various approaches are used to reduce intravesical pressure during transurethral resection of the prostate (TURP). With a view to finding a target pressure for such efforts, pressure and fluid absorption were compared in a meta-analysis of four previous studies comprising three different irrigation techniques.

MATERIALS AND METHODS

Intravesical pressure was recorded during TURP in which the irrigating fluid was evacuated intermittently (n = 48) by a suprapubic tube (n = 23) or a trocar (n = 30). Fluid absorption was compared with the mean and maximum pressures and the duration of excessive pressure (>2 kPa) over 10-min periods.

RESULTS

Mean bladder pressure during fluid absorption was between 1.0 and 2.5 kPa. The maximum pressure during absorption varied greatly during the first 30 min of TURP, but thereafter it ranged between 2 and 3 kPa. Only the duration of pressures >2 kPa increased with fluid absorption (p < 0.02). The maximum pressures were highest with the intermittent technique, while the other indices of intravesical pressure showed the highest values when the suprapubic tube was used. The lowest pressures usually occurred when the trocar was used, but fluid absorption still occurred, as the pressure was much higher during some of these operations.

CONCLUSIONS

Fluid absorption occurred at moderate intravesical pressures with all three irrigation techniques. The best strategy for reducing fluid absorption is to keep the pressure below 2 kPa for as long as possible during TURP.

Incidence of acute myocardial infarction and cause-specific mortality after transurethral treatments of prostatic hypertrophy

OBJECTIVES

Transurethral resection of the prostate (TURP) is associated with a higher long-term mortality than open prostatectomy which has been ascribed to a higher incidence of acute myocardial infarction (AMI). To assess the possible excess risk associated with TURP, we studied the incidence of AMI and the cause-specific mortality in patients treated with TURP and transurethral microwave thermotherapy (TUMT).

METHODS

Patients treated for benign prostatic hypertrophy at a university hospital (888 patients with TURP and 478 with TUMT) were monitored during an average follow-up period of 3.9 years. The incidence of AMI and the causes of death were compared with those in the general population.

RESULTS

Both treatments were followed by a higher incidence of AMI than in the general population, in particular from 2 years or more after treatment (standardized morbidity ratio 1.50, 95% confidence interval [CI] 1.14 to 1.93). The long-term mortality from all causes was increased in patients younger than 75 years of age when undergoing any of the treatments (standardized mortality ratio [SMR] 1.16, 95% CI 0.97 to 1.39), in particular, death from cardiovascular diseases (SMR 1.25, 95% CI 0.95 to 1.60) and tumors (SMR 1.54, 95% CI 1.14 to 2.03).

CONCLUSIONS

The similarity of the results for TURP and TUMT suggests that the prostatic enlargement rather than the treatment is associated with cardiovascular disease.

Comparison of urological irrigating fluids containing glycine and mannitol in volunteers

BACKGROUND

We compared symptoms and indices of fluid distribution after experimental administration of glycine and mannitol solutions, since these irrigating fluids are sometimes absorbed by the patient during genitourinary surgery.

METHODS

Glycine 1.5% and mannitol 3%, both with ethanol 1% added, were given by intravenous infusion at a rate of 0.5 ml/kg/min during 30 min to 12 male volunteers. Symptoms, cognitive status, hemodynamics, electrocardiogram during 24 hr, computerized tomography of the brain, bioimpedance, blood chemistry, and breath ethanol concentrations were recorded.

RESULTS

Glycine was associated with more symptoms than mannitol (P< 0.006), but the cognitive status, computerized tomography examinations, electrocardiograms, and breath ethanol concentrations did not differ between the solutions. The urinary excretion of fluid and sodium was greater after mannitol (P< 0.04), while only the glycine infusions hydrated the cells (P< 0.05). For both fluids, the intravascular and interstitial volumes were below baseline 3 hr after the experiment started (P< 0.01).

CONCLUSIONS

Glycine 1.5% had a higher tendency than mannitol 3% to cause symptoms and to accumulate in the cells.

Blood ammonia levels after intravenous infusion of glycine solution with and without ethanol

OBJECTIVE

Absorption of glycine 1.5% during transurethral resection of the prostate may increase blood ammonia levels, but hyperammonaemia has not been described when the fluid also contained ethanol 1%. The aim of this experimental study was to evaluate whether ethanol 1% reduces glycine-induced hyperammonaemia.

MATERIAL AND METHODS

Two intravenous infusions of glycine solution with and without ethanol 1% added were given on different occasions to 20 male volunteers (mean age 30 years). Half of them received 22 g of glycine over 50 min and the others approximately 18 g over 30 min. Blood ammonia was measured before and 30 min after the infusion. The serum levels of free amino acids were measured on 7 occasions during 10 of the experiments.

RESULTS

The glycine infusions increased blood ammonia levels from 37 micromol/l (median, 10th and 90th percentile limits 34-53) to 57 micromol/l (27-110; p < 0.001). The change was greater after the larger glycine dose, regardless of whether the fluid contained ethanol (p < 0.05). The only amino acid concentration correlating with blood ammonia was glycine, which showed higher levels in those who had a rise in blood ammonia of 50% or more.

CONCLUSIONS

Ethanol 1% did not reduce the increase in blood ammonia concentration after the administration of glycine solution.

Thrombotic risk factors associated with transurethral prostatectomy

OBJECTIVE

To ascertain the potential thrombotic risk associated with transurethral prostatectomy (TURP).

PATIENTS AND METHODS

The changes in coagulation variables were assessed in a prospective study of 40 patients undergoing TURP.

RESULTS

There was a significant increase in thrombin-antithrombin complexes 6 h after TURP (anova, P=0.01) combined with a significant decrease in activated partial thromboplastin time (anova, P=0.006), suggesting a postoperative hypercoagulable state. The significant increase in d-dimer 24 h after TURP (anova, P=0.015) in the absence of any significant rise in tissue plasminogen activator antigen levels perioperatively (anova, P=0.737) suggests a physiological fibrinolytic response to the developing procoagulant state. The absence of any significant increase in plasminogen activator inhibitor-1 antigen perioperatively (anova, P=0.348) suggests the observed hypercoagulability is not due to a 'fibrinolytic shutdown' reported in other forms of surgery.

CONCLUSION

TURP is associated with a hypercoagulable prothrombotic state; aspirin withdrawal perioperatively may be hazardous, and low-dose heparin prophylaxis for venous thrombosis should be considered.