Visual evoked potentials and visual acuity after transurethral resection of the prostate

Changes in visual evoked potentials, visual acuity, blood ammonia levels and serum electrolytes (Na+ and K+) after transurethral resection of the prostate using glycine as an irrigating fluid performed under subarachnoid block were studied in 12 patients, in the pre-operative and immediate postoperative periods. Visual evoked potentials (p100 latency), recorded by shift of a checkerboard pattern, increased significantly from a pre-operative value of mean (SEM) 101.18 (1.63) msec in the right eye, and 102.5 (1.47) msec in the left eye to 108.91 (1.8) msec (p less than 0.01) and 108.08 (2.53) msec (p less than 0.01) respectively in the postoperative phase. There were no changes in visual acuity as assessed by a Snellen's chart, blood ammonia levels and serum electrolyte concentrations. The amount of glycine used intra-operatively for irrigation ranged from 3 to 31 litres.     

Hyperammonemia after transurethral resection of the prostate: a report of 2 cases

We report on 2 patients who became deeply comatose after transurethral resection of the prostate. Both patients were severely hyponatremic and hyperammonemic but the course of the comas followed serum ammonia concentrations more closely than serum sodium concentrations. The genitourinary irrigant used in both procedures was a 1.5 per cent glycine solution. Serum amino acid analyses in 1 patient suggested that the postoperative hyperammonemia was due to catabolism of glycine absorbed during surgery. The inadequate activation of normal pathways of ammonia metabolism in this patient may have been caused by a partial deficiency of the urea cycle enzyme argininosuccinate synthetase. We believe that hyperammonemia should be considered as a cause of encephalopathy after transurethral resection of the prostate. The 1.5 per cent glycine genitourinary irrigating solution may not be as nontoxic as generally believed.     

The effect of the choice of irrigation fluid on cardiac stress during transurethral resection of the prostate: a comparison between 1.5% glycine and 5% glucose

PURPOSE: Variable amounts of irrigation fluid are absorbed during transurethral prostate resection. Previous studies suggest that cardiac stress occurs as a result of transurethral prostate resection, possibly due to glycine absorption. We performed a prospective, blinded, randomized trial comparing 1.5% glycine with 5% glucose irrigating solution. We assessed whether glycine or glucose irrigation for transurethral prostate resection is associated with cardiotoxicity, as measured by troponin I and echocardiogram changes. MATERIALS AND METHODS: Between December 2001 and March 2003, 250 patients were recruited. Changes in immediate postoperative vs preoperative echocardiogram and serum cardiac troponin I indicated perioperative myocardial stress. Intraoperative irrigating fluid absorption was measured with 1% ethanol as a marker. Operative details recorded were anesthesia type, resection time, resected tissue weight and temperature change. Blood loss was measured with transfusions considered. Postoperatively blood assessments included serum glycine assay. RESULTS: Five patients (4%) in the glycine group and 3 (2%) in the glucose group had significantly increased troponin I after surgery. Of these men 1 per group had myocardial infarction and the remainder had transient ischemia. Logistic regression was used to identify factors associated with an unfavorable outcome, which was recorded as a significant increase in troponin I or ischemic changes on echocardiography. Increasing patient age and blood loss were associated with an unfavorable outcome (OR 1.84 and 1.24, respectively). We noted no significant differences in the 1.5% glycine and 5% glucose groups with regard to troponin I/echocardiogram. However, when the glycine assay was compared with adverse outcomes, an increased glycine assay was found to be associated with echocardiogram changes (p = 0.001) and with increased troponin I levels (relative risk 10.71). CONCLUSIONS: Transurethral prostate resection has an effect on the myocardium perioperatively. Glycine absorption causes echocardiogram changes and it is associated with increased troponin I. Increasing patient age and blood loss are associated with myocardial insult. The risk of increased blood loss was accumulative with each unit lost. Unrecognized blood loss or glycine absorption may explain the increase in morbidity and mortality previously reported in patients who undergo transurethral prostate resection.     

Osmotic and metabolic sequelae of volumetric overload in relation to the TUR syndrome

In an attempt to understand the pathophysiology of the transurethral resection syndrome this prospective metabolic study was conducted on 100 consecutive patients undergoing transurethral resection of the prostate (TURP). The volume of glycine absorbed, intravenous fluid given and blood loss were calculated, and serum osmolality, sodium and glycine were measured before, during and after operation. The mean volume of glycine absorbed, fluid gain and blood loss were 0.6, 1.57 and 0.356 litres respectively. The mean weight of prostate resected was 30.8 g and resection time was 56.5 min. The mean serum osmolality dropped from 291 to 286 mOsm/l, sodium dropped from 138 to 132 mmol/l and glycine concentration increased from 293 to 3599 mumol/l post-operatively. Ten patients developed signs suggestive of the TURP syndrome. Multiple regression analysis showed that the most consistent statistically significant factors in relation to the syndrome were volumetric gain and hypo-osmolality. The latter proved to be the only significant factor later post-operatively. The increase in serum glycine and drop in serum sodium concentrations were the best serological markers, reaching significance only after excluding volumetric gain and osmolality from the analysis.     

Transient blindness following transurethral resection of the prostate in an achondroplastic dwarf

Neurological complications associated with transurethral resection of the prostate have been reported in the past. We report on an achondroplastic dwarf who suffered transient blindness following transurethral resection of the prostate. The blindness correlated with a markedly elevated serum glycine level of 13,734 mumol. per l. We discuss the possibility of glycine being responsible for this complication.     

Bipolar transurethral resection in saline--an alternative surgical treatment for bladder outlet obstruction?

PURPOSE: The transurethral resection in saline system uses bipolar energy for transurethral prostate resection, thus, avoiding the need for glycine irrigation and its associated complications. We compared the clinical efficacy and safety of bipolar transurethral resection in saline and of monopolar transurethral prostate resection for symptomatic benign prostate hyperplasia. MATERIALS AND METHODS: From January 2005 to June 2006, 238 consecutive patients with symptomatic benign prostate hyperplasia were randomized into a prospective, controlled trial comparing the 2 treatment modalities. Patient demographics, operative time, hospital stay and complications were noted. Serum hemoglobin and electrolytes were determined in all patients immediately before and after the endoscopic procedure. RESULTS: During 18 months 120 patients were randomized to the conventional transurethral prostate resection group and 118 were randomized to the transurethral resection in saline group. Patient profiles, weight of resected prostatic tissue and duration of hospitalization were similar in the 2 groups. The decrease in serum sodium and serum chloride was statistically significantly greater in the transurethral prostate resection group than in the transurethral resection in saline group (each p = 0.05). The transurethral resection in saline procedure required significantly more time (mean 56 vs 44 minutes, p <0.01). There was 1 case (0.8%) of transurethral resection syndrome in the transurethral prostate resection group but none in the transurethral resection in saline group. Postoperative bleeding did not significantly differ between the 2 groups. Clot retention was observed in 6 (5%) and 4 patients (3%) in the transurethral prostate resection and transurethral resection in saline group, respectively. Two repeat interventions were required in the transurethral prostate resection group. CONCLUSIONS: The bipolar transurethral resection in saline system is as efficacious as monopolar transurethral prostate resection but it is safer than the latter because of the lesser decrease in postoperative hypernatremia and the smaller risk of transurethral resection syndrome. However, probably due to technical reasons, transurethral resection in saline operative time is significantly longer.     

Transurethral resection syndrome. A prospective study.

Significant hyponatraemia has been reported following transurethral prostatectomy (TURP) in 11-41% of cases. The majority of previous studies have been performed retrospectively. A prospective study was undertaken of 100 patients undergoing TURP. In all, a 24-Charr sheath with non-irrigating, resectoscope and 1.5% glycine as irrigant was used. Volume of irrigant used, weight of prostate and length of procedure were recorded. Serum electrolytes were measured at anaesthetic induction and immediately on transfer to the recovery room. In none of the 100 patients was there a statistically significant fall in serum sodium following resection. No clinical changes of transurethral resection (TUR) syndrome occurred. This study confirms that TUR syndrome and a significant fall in serum sodium can be virtually prevented in TURP and the use of an irrigating resectoscope or a trocar in the average case is not necessary.     

Glycine and transurethral resection

Fifty patients undergoing transurethral resection of the prostate were studied for evidence of glycine absorption and haemodilution. Plasma glycine levels increased substantially in nine patients and, in five, calculated irrigant fluid absorption ranged from 619-1582 ml; another patient had absorbed 1360 ml fluid with only a small rise in plasma glycine. Two illustrative case histories are presented. The role of glycine as an inhibitory neurotransmitter is discussed and the possibility of toxic mechanisms other than dilutional hyponatraemia is mentioned. Intravenous diuretics, hypertonic saline, and perhaps calcium salts, are recommended for the overt transurethral resection syndrome.     

Dose-dependent half-life of glycine

Summary The serum concentration of glycine was measured at hourly intervals after administration of between 10 and 91 g glycine to 17 patients undergoing transurethral resection of the prostate and of between 15 and 22 g glycine to 18 volunteers by intravenous infusion. The apparent half-life of glycine varied 10-fold (range 26–245 min) and increased in direct proportion to the amount of glycine given. This result can be explained by assuming a marked intracellular accumulation of a surplus of glycine. The dose-dependent half-life means that patients who absorb large amounts of irrigating fluid are exposed to excessive blood levels of glycine for a prolonged period of time.     

Independent plasma levels of sodium and glycine during transurethral resection of the prostate

This study was done to evaluate the potential role of plasma glycine levels as an indicator of the biochemical changes occurring during or shortly after transurethral resection of the prostate (TURP). Seventeen patients undergoing TURP were studied to determine the fate of the absorbed glycine and its effects on other amino acids and their relationship to changes in serum sodium and osmolarity. Twelve patients showed more than 100 per cent increase in plasma glycine levels with values ranging to more than 100-fold elevation. Only two patients showed a change in serum sodium of greater than 10mEqll with corresponding change in osmolarity. In one such patient there was no accompanying change in plasma glycine. Thus, major changes in plasma glycine and serum sodium may occur independently of one another, and may separately account for manifestations of the reactions following TURP.     

Are there acid base changes during transurethral resection of the prostate (TURP)?

Acid base status during transurethral resection of the prostate (TURP) has been almost neglected. We therefore measured the acid base status and interpreted the observed changes according to the Stewart approach. The Stewart model focuses more on the influence of serum electrolyte concentrations on acid base changes than does the conventional Henderson-Hasselbalch approach. In 20 patients undergoing TURP, the following variables were determined: PaO(2), PaCO(2), pH(a), actual bicarbonate, standard base excess, serum concentration of sodium, potassium, chloride, lactate, and total protein. A study group (n = 11) and a control group (n = 9) were built, depending on the maximal amount of fluid absorption estimated with the aid of ethanol concentration monitoring in the expired gas. The study group developed a mild acidosis with a decrease in pH from 7.41 to 7.37 (P = 0.037), compared with a very discrete pH decrease from 7.44 to 7.42 in the control group. We found that moderate irrigant absorption during TURP leads to a specific metabolic acidosis. We speculate that larger amounts of irrigant absorption may cause a more severe metabolic acidosis. As the constellation of independently pH regulating variables appears to be typical for TURP, this acidosis could be named "TURP-acidosis." IMPLICATIONS: We measured acid base status in 20 patients undergoing transurethral resection of the prostate comparing a larger fluid absorption group with a minor or no fluid absorption group. We postulate the development of a typical metabolic transurethral resection of the prostate-acidosis caused by irrigant absorption.     

Serum amino acid patterns and toxicity symptoms following the absorption of irrigant containing glycine in transurethral prostatic surgery

The relationships between the serum concentrations of amino acids, the volume of irrigating fluid absorbed and symptoms of glycine toxicity were analysed in 18 patients who had undergone transurethral resection of the prostate and in whom intravascular absorption of irrigating fluid containing 2.2% glycine had been recorded. A mean of 7% of the transferred glycine could be detected in the serum within 10 min of irrigant absorption. The half-life of glycine in serum was twice as long when the volume of irrigant absorbed exceeded 1500 ml (100 min; n = 6), and the serum levels of alanine, aminobutyrate, proline and serine were significantly more elevated, than when the volume of irrigant absorbed was between 900 and 1300 ml (n = 6). Where the amount of glycine transferred exceeded 0.5 g.kg-1, symptoms of glycine toxicity developed, their onset coinciding with a rapid increase in the serum levels of non-essential amino acids other than glycine.     

Isotonic hyponatremia following transurethral prostate resection.

The proper treatment of hyponatremia during transurethral resection of the prostate continues to be controversial. Two cases of isotonic hyponatremia are reported here, and the literature regarding the incidence and treatment of hyponatremia during transurethral resection of the prostate is reviewed. In each case, the patient developed neurologic changes during complicated transurethral prostate resection. Despite the rapid decrease in the serum sodium concentration, serum osmolality remained normal due to the resorption of the bladder irrigant glycine. Therefore, etiologies other than cerebral edema are postulated as the cause of the neurologic manifestations. Also, the role of the osmolar gap in directing appropriate therapy is emphasized in an effort to avoid unnecessary use of hypertonic saline. Finally, an appropriate differential diagnosis of the neurologic changes seen during the transurethral resection of the prostate syndrome is discussed.     

Transurethral prostate resection and bleeding: a randomized,placebo controlled trial of role of finasteride for decreasing operative blood loss

PURPOSE: Bleeding associated with transurethral prostate resection can often be significant and lead to increased morbidity and occasionally mortality. It has been shown that finasteride decreases bleeding in patients with hematuria of prostatic origin. We hypothesized that bleeding in patients undergoing transurethral prostate resection could be decreased by giving finasteride for 2 weeks before surgery. MATERIALS AND METHODS: A total 70 patients scheduled to undergo elective transurethral prostate resection were randomized to receive 5 mg. finasteride daily or placebo for 2 weeks before surgery. Serum hemoglobin was measured before and after surgery, and the following day. The volume of irrigation fluid used and its hemoglobin concentration as well as resected prostate weight were recorded. RESULTS: Of the 68 patients who underwent transurethral prostate resection 2 were withdrawn before surgery, and so 32 received finasteride and 36 received placebo. There was significantly less mean blood loss in irrigation fluid in the finasteride group than in the control group (43.6 versus 69.3 gm. hemoglobin, p = 0.011). The mean difference was more significant when blood loss per gm. resected prostate was calculated (2.65 versus 4.65 gm. hemoglobin per gm. prostate, p < 0.01). CONCLUSIONS: This study shows that finasteride given for 2 weeks preoperatively decreases bleeding in patients undergoing transurethral prostate resection. Further study is required to determine the optimal timing and dose duration to minimize blood loss and identify how relevant such a decrease in bleeding is in clinical practice.     

Hyponatraemia after transurethral resection of the prostate

Transurethral resection (TUR) syndrome is a complication of transurethral resection of the prostate characterized by bradycardia, hypotension and postoperative confusional state, which is generally attributed to hyponatraemia occurring during or immediately after operation. In a prospective study of 100 consecutive patients undergoing transurethral resection of the prostate, changes in serum sodium were estimated before and after operation and correlated with various parameters including weight of prostate resected, volume of irrigant fluid and resection time. Seven patients showed a significant drop (greater than 10 mmol/litre) in serum sodium: two of these had the clinical features of TUR syndrome and one of them died. The pathogenesis and management of this syndrome are discussed.     

Morbidity of radical perineal prostatectomy following transurethral resection of the prostate

Radical prostatectomy in patients who have had prior transurethral resection of the prostate has been reported to result in significant morbidity. From 1974 to 1982, 30 patients who had had previous transurethral resection of the prostate underwent radical perineal prostatectomy for localized prostatic cancer. Operative time and blood loss were similar to a group of patients who had not had prior transurethral resection of the prostate. Over-all, 3 patients (10 per cent) had total incontinence and 3 (10 per cent) had stress incontinence requiring a pad or device. No patient undergoing radical prostatectomy less than 4 weeks or more than 4 months after transurethral resection of the prostate had postoperative incontinence. When radical perineal prostatectomy was performed between 4 weeks and 4 months after transurethral resection of the prostate the incidence of incontinence was 50 per cent. Five patients experienced prolonged perineal urinary drainage, all but 1 of whom healed spontaneously. Of the 6 patients with incontinence 3 had prolonged drainage. No patient had a rectal injury and there was no operative mortality. Two patients died without cancer and 1 has evidence of disease recurrence. We conclude that radical prostatectomy may be performed safely with acceptable morbidity following transurethral resection of the prostate and that if 4 weeks has elapsed since resection it might be advantageous to wait 4 months before performing radical surgery to lessen the risk of incontinence.     

In vitro technique for isolating prostatic cells from blood.

An in vitro technique for isolating prostatic cells from blood has been applied to the study of circulating prostatic cells during a transurethral resection of the prostate. Our findings indicate that prostatic cells that are added to the blood in vitro can be isolated by the technique described and that cells resembling prostatic cells can be isolated from the blood of the patient undergoing transurethral resection of the prostate. Furthermore, the results of our study suggest that (i) in selected patients, needle biopsy of the prostate should be carried out prior to transurethral resection of the prostate and that (ii) patients who have multifocal adenocarcinoma diagnosed at the time of transurethral resection of the prostate may not be suitable candidates for future prostatectomy.     

Surgical outcomes for men undergoing laparoscopic radical prostatectomy after transurethral resection of the prostate

PURPOSE: We reviewed outcomes for men with a history of transurethral prostate resection who underwent laparoscopic radical prostatectomy for prostate cancer. MATERIALS AND METHODS: Between January 26, 1998 and December 2006, 3,061 men underwent laparoscopic radical prostatectomy at our institution. A retrospective review showed that 119 had a history of transurethral prostate resection. These men were compared to randomized matched controls with regard to operative and postoperative outcomes. The matching criteria used to randomly select patients were clinical stage, preoperative prostate specific antigen and biopsy Gleason score. RESULTS: Mean +/- SD age in the groups with and without transurethral prostate resection was 66.2 +/- 5.6 and 60.7 +/- 7.0 years, respectively (p <0.01). Mean estimated blood loss, transfusion rate, pathological prostate volume and reoperation rate were statistically similar between the groups. Mean length of stay for the groups with and without transurethral prostate resection was 6.5 +/- 3.0 and 5.29 +/- 2.3 days, respectively (p <0.01). Mean operative time for the groups with and without transurethral prostate resection was 179 +/- 44 and 171 +/- 38 minutes, respectively (p = 0.02). Positive margins were seen in 21.8% and 12.6% of the patients with and without transurethral prostate resection, respectively (p = 0.02). A total of 64 complications were seen in patients with a history of transurethral prostate resection compared to 34 in those without such a history (p <0.01). CONCLUSIONS: We report that patients with a history of transurethral prostate resection who undergo laparoscopic radical prostatectomy have worse outcomes with respect to operative time, length of stay, positive margin rate and overall complication rate. This subset of patients should be made aware of these potential risks before undergoing laparoscopic radical prostatectomy.     

Transurethral resection of the prostate, serum glycine levels, and ocular evoked potentials

Complications of transurethral resection of the prostate (TURP syndrome) when glycine is used as the irrigating fluid include cardiovascular and central nervous system abnormalities that occasionally include transient blindness. Serum sodium, glycine, potassium, chloride, ammonia, osmolality, carbonate, and blood urea nitrogen of 17 patients having TURP and 10 having cystoscopic examination were measured. Electroretinograms and visually evoked potentials (VEPs) were recorded in the preanesthetic preparatory area and in the recovery room immediately after surgery. Four patients reported visual aberrations coincident with increases in serum levels of glycine from a mean before surgery of 137.7 +/- 45.1 to 7,812.2 +/- 2,486.6 microM/l, mean +/- SD, after TURP. These patients also showed a reduction of serum sodium from 138 +/- 4.5 to 122 +/- 8.6 mEq/l that correlated significantly with serum levels of glycine (rho = -0.81). There were no statistically significant changes of serum ammonia and osmolality. Electroretinograms consistently demonstrated complete loss of oscillatory potentials. Thirty hertz flicker-following was also abolished. VEPs were more variably affected with prolongation of component "P100" latency found in both groups and probably resulting from sedative effects of diazepam. Patients experiencing the TURP syndrome showed abolishment of 30 Hz flicker-following in their VEPs. The elevated serum levels of glycine may contribute directly to visual aberrations resulting from glycine's role as an inhibitory transmitter in the retina.     

Increased prostatic lysophosphatidylcholine acyltransferase activity in human prostate cancer: a marker for malignancy

PURPOSE: Phospholipase A2 and lysophosphatidylcholine acyltransferase (LAT) constitute a deacylation-reacylation cycle that incorporates arachidonic acid into the lipid membrane. In a preliminary report we found increased LAT activity in malignant prostate tissue. We measured LAT activity in prostate tissue from a large number of patients undergoing prostatectomy. MATERIALS AND METHODS: Prostate tissue from 93 patients undergoing radical prostatectomy for prostate carcinoma, 14 undergoing cystoprostatectomy for bladder cancer, 55 undergoing transurethral resection for benign prostatic hyperplasia and 11 with prostate cancer undergoing transurethral resection for relief of obstructive symptoms was analyzed for LAT activity. RESULTS: In radical prostatectomy specimens using oleoyl coenzyme A as substrate mean increase in LAT activity between malignant and benign portions of the same specimen was 0.68 +/- 0.12 nmol./mg. protein per minute (p <0.00001). In all radical prostatectomy specimens analyzed LAT activity was 43% higher in the malignant than benign portions (2.25 +/- 0.15 versus 1.57 +/- 0.11 nmol./mg. protein per minute, p <0.001). In the 10 benign prostate specimens obtained from cystoprostatectomy mean LAT activity was 1.12 +/- 0.18 nmol./mg. protein per minute, which was significantly lower than that of benign portions of radical prostatectomy (p <0.05). LAT activity in benign cystoprostatectomy specimens was significantly higher than that in the 50 benign transurethral resection specimens (0.54 +/- 0.05, p <0.01), possibly due to heat damage in transurethral resection specimens during collection. However, LAT activity in transurethral resection specimens from patients with known prostate cancer was similarly increased. Similar results were obtained using arachidonoyl coenzyme A. CONCLUSIONS: We demonstrated increased LAT activity in malignant tissue from patients with prostate cancer. Thus, the deacylation-acylation remodeling cycle may be enhanced to provide more arachidonic acid to meet the demand for prostaglandin E2 synthesis in malignant tissue.