A COMPARISON OF 1.5% GLYCINE AND 2.7% SORBITOL-0.5% MANNITOL IRRIGANTS DURING TRANSURETHRAL PROSTATE RESECTION

Usefulness of non-invasive cardiac output monitoring in elderly patients undergoing monopolar transurethral resection of the prostate: a pilot study

Objective

To assess the impact of irrigating fluid on hemodynamic profiles using real-time non-invasive cardiac output monitoring (NICOM) in elderly patients undergoing monopolar transurethral resection of the prostate (TURP).

Methods

Twenty patients between 65 and 80 years of age who were scheduled for monopolar TURP and received spinal anesthesia up to T10 were enrolled. Irrigating fluid (2.7% sorbitol with 0.5% mannitol solution) was used. Hemodynamic profiles including cardiac index, and stroke volume variation (SVV) using NICOM were obtained. Estimated irrigating fluid absorption was indirectly calculated.

Results

The median amount of irrigating fluid used was 6000 mL. The median SVV was 11%, which increased to 12% at 10 minutes after initiating surgery. No significant changes in the cardiac index were observed. The estimated absorption of irrigating fluid was almost zero.

Conclusions

Although the estimated amount of irrigating fluid that was absorbed was negligible, the increase in SVV may indicate intravascular volume depletion with diuresis resulting from mannitol in the irrigating fluid early during irrigation. Therefore, even during short irrigating times, intensive hemodynamic monitoring should be performed to monitor the possibility of intravascular volume depletion as well as volume overload, especially immediately after large amounts of irrigating fluid are used.

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.

Treatment of bladder tumors and benign prostatic hyperplasia with a new TUR system using physiological saline as perfusate

This article presents a new transurethral resection (TUR) system for use in endoscopic surgery. By using an electroconductive solution (physiological saline) as the perfusate in lieu of conventional non-electroconductive solution (Uromatic), additional anesthesia (e.g., obturator nerve blocking) is not required. The new TUR is carried out in an electroconductive solution such as saline, and because radiofrequency current flows from the resecting electrode through the perfusate to the outer sheath, no counter-electrode is needed. We have treated both bladder tumor and benign prostatic hyperplasia cases with this new system. Surgery was safely performed in all TUR-bt cases without requiring obturator nerve blocking. During both TUR-bt and transurethral resection of the prostate (TUR-P) using this system, tissue resection and coagulation equivalents were similar to the conventional TUR system. In previous TUR, preoperative obturator nerve blocking was necessary, and in some cases, incomplete blocking or complications occurred. When physiological saline is used as the perfusate, blood electrolyte levels are not greatly changed, even after extensive resection of the bladder wall; as a result, this new system is also cost effective because physiological saline is less expensive than non-electroconductive solutions and requires no counter-electrode. Thus, in comparison with conventional TUR, this new system is both significantly safer and more cost effective.

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.

TROPONIN T AND N-TERMINAL PRO-BRAIN NATRIURETIC PEPTIDE CHANGES IN PATIENTS UNDERGOING TRANSURETHRAL RESECTION OF THE PROSTATE

PURPOSE

We investigated whether transurethral resection of the prostate (TURP) caused subclinical myocardial damage or cardiac dysfunction by measuring troponin T (Trop T) and N-terminal pro-brain natriuretic peptide (pro-BNP).

MATERIALS AND METHODS

A total of 52 consenting patients took part in this study. All had a detailed medical history including cardiac history taken. On the day of the operation all patients had troponin T, pro-BNP, full blood count and urea, electrolytes and creatinine measured preoperatively. A preoperative and postoperative electrocardiogram was performed. Patients in renal failure were excluded from analysis. During the operations factors such as blood loss, operative time, tissue resected and fluid absorption were monitored. On postoperative day 1 all the previously mentioned tests were repeated.

RESULTS

Mean patient age was 71 years (range 52 to 85). Eight patients had a history of associated cardiac problems. Mean preoperative and postoperative hemoglobin were 14.1 gm/dl (range 10.5 to 17) and 13.3 gm/dl (range 9.9 to 16.2), respectively. None of the patients had significant (greater than 1,000 ml) fluid absorption during TURP, which was calculated using ethanol tagged glycine. Mean blood loss measured with a photometer was 129.7 ml (range 0 to 1,800). Mean operative time was 28.4 minutes (range 5 to 50) and mean weight of prostatic tissue resected was 15.2 gm (range 1 to 47). Preoperative Trop T was less than 0.01 mcg/ml in all patients and mean pro-BNP was 39.2 pg/ml (range 0.5 to 866). Postoperative Trop T was less than 0.01 mcg/ml in all but 1 patient who experienced chest pain after TURP and had an increased Trop T (0.28 mcg/ml). Mean postoperative pro-BNP was 54.57 pg/ml (range 1 to 679). A total of 37 patients had an increase in pro-BNP which was still within the reference range for the age group. There were no significant electrocardiogram changes postoperatively. The Trop T changes were not statistically significant (Wilcoxon sign ranked test p = 0.31) although they may be clinically significant.

CONCLUSIONS

Our study indicates that in patients with no prior cardiac history TURP does not cause myocardial damage indicated by nonincrease of Trop T. There are slight increases in pro-BNP after TURP in some patients although the exact clinical significance is uncertain.

A new transurethral resection system: operating in saline environment precludes obturator nerve reflexes

PURPOSE

We developed a transurethral resection system comprising a uniquely designed resectoscope and high frequency wave generator. The obturator nerve is free of electrical stimulation during transurethral resection since high frequency current is delivered via a resection loop to the sheath of the resectoscope in saline irrigation. Preclinical verification of the system was performed in an animal model to ensure its efficacy and operational safety.

MATERIALS AND METHODS

The swine bladder wall was transurethrally resected using the system in a saline environment. Results were subsequently compared with data on identical resection performed with the conventional system in sorbitol solution irrigation. Electrolyte contents were measured after resection for comparative evaluation with corresponding pre-resection data. Also, the depth of heat degeneration was measured in resected tissue.

RESULTS

No additional skills were required for bladder resection performed with the new system versus the conventional system. No lower limb adductor contraction was noted except minimal creeping during resection of a site close to the urethra. There were no apparent anomalies of blood electrolytes after transurethral resection. No difference was observed in the mean depth of heat degenerated tissues compared with the conventional system.

CONCLUSIONS

The newly developed transurethral resection system was effective in a saline irrigated environment, which inhibited the obturator nerve reflex when applied in an animal model. This finding suggests promising potential for the system as a safe and cost-effective alternative compared with conventional transurethral resection.