A method of measuring fluid balance during transurethral resection of the prostate

Novel strategy to monitor fluid absorption and blood loss during urological endoscopic surgery

Background

There is paucity of an optimal method to detect fluid absorption and hemorrhage during urological endoscopic surgery. We designed an endoscopic surgical monitoring system (ESMS) and estimated its performance to establish a practical instrument that can monitor the blood loss and fluid absorption accurately and non-invasively during urological endoscopic surgery.

Methods

Our system employed the strain gauge transducers to detect the inflows and outflows of the irrigating solutions and the photoelectric sensor to determine the hemoglobin concentration of the collected irrigating fluid. The amount of blood lost and the volume of fluid absorbed during endoscopic surgery could be calculated by computer program. The accuracy and validity of this system were validated in simulated experiment and clinical study of 200 patients who underwent transurethral resection of the prostate (TURP).

Results

The relative errors for fluid absorption detection were between 0.07% and 1.00% and the coefficient of variation in serial analysis ranged from 0.78% to 3.86%. Furthermore, the relative errors for blood loss detection were between 0.06% and 1.33% and the coefficient of variation in serial analysis ranged from 0.86% to 3.94%. In clinical study for TURP, the mean fluid absorption was 644 mL and blood loss was 238 mL.

Conclusions

We provide the accuracy and validity of ESMS. It provides an early and real time detection and warning of irrigation fluid absorption and blood loss to make endoscopic surgical procedure safer for the patient.

Electrolyte changes: An indirect method to assess irrigation fluid absorption complications during transurethral resection of prostate: A prospective study

Context:

Fluid absorption is inevitable complication of transuretheral resection of prostate and serum electrolytes changes can indirectly assess the irrigation fluid absorption.

Aims:

To monitor the extent of 1.5% glycineirrigation fluid absorption during transurethral resection of prostate (TURP), by measuring the changes of serum sodium and potassium levels peri-operatively.

Settings and Design:

This is a randomized prospective cohort observational study.

Materials and Methods:

The 86 male patients of ASA grades I to III in the age group of 50 to 80 years, scheduled for elective TURP surgery under central neuraxial block, were studied. Their preoperative and post-operative serum sodium, potassium and calcium levels were measured. When duration of surgery exceeds 60 min, serum sodium and potassium levels were done intra-operatively with venous blood samples by using blood gas analyser. The height of irrigation fluid column was kept constant at 60 cm. These changes were correlated with the volume of irrigating fluid used, duration of procedure and the volume of prostate gland resected.

Statistical Analysis used:

The values of pre and postoperative sodium, potassium and calcium serum levels were compared and statistical significance of the difference in values was assessed using Student’s paired t test.

Results:

Statistically significant reduction of serum sodium levels (hyponatremia) and elevation of serum potassium levels (hyperkalemia) were observed post-operatively, which was directly proportional to volume of irrigating fluid used, duration of procedure and volume of prostate gland resected. No significant changes in serum calcium level were observed.

Conclusions:

To measure serum electrolytes changes during TURP surgery, it is simple and economical method for indirect assessment of fluid absorption for early identification of TURP syndrome.

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.

A prospective, randomized trial comparing conventional transurethral prostate resection with PlasmaKinetic vaporization of the prostate: physiological changes, early complications and long-term followup

PURPOSE

We compared standard transurethral prostate resection with bipolar PlasmaKinetic prostate vaporization for bladder outflow obstruction using a Gyrus PlasmaKinetic Plasma V bar.

MATERIALS AND METHODS

A total of 160 men were enrolled in a prospective, randomized trial. Those at higher risk for cancer were excluded by prostate specific antigen and digital rectal examination with or without transrectal ultrasound biopsy. A total of 81 men underwent prostate vaporization and 79 underwent transurethral prostate resection. Preoperative International Prostate Symptom Score and quality of life score, uroflowmetry, post-void residual urine and transrectal ultrasound prostate volume were recorded. Preoperative and postoperative serum hemoglobin, hematocrit and sodium were measured. Perioperative fluid absorption was calculated using weighing on table and blood loss using the Hemocue system. Longer followup of International Prostate Symptom Score and quality of life score, uroflowmetry and post-void residual urine was available in 149 men, including 76 who underwent prostate vaporization and 73 who underwent transurethral prostate resection. Data were analyzed using the 1 or 2-sample t and chi-square tests.

RESULTS

The 2 groups were comparable in all preoperative parameters. Perioperative fluid absorption, intraoperative blood loss, preoperative and postoperative serum hematocrit, and sodium changes were not statistically different. Mean resection time was 4 minutes shorter for transurethral prostate resection (28.5 vs 32.6 minutes, p = 0.08). Patients with transurethral prostate resection showed a greater hemoglobin decrease (1.39 vs 0.8 gm/dl, p = 0.002) and required more irrigation postoperatively (28.3 vs 20.4 l, p = 0.001). Four patients with transurethral prostate resection required transfusion compared with none who underwent prostate vaporization. After transurethral prostate resection hospital stay was longer (3.36 vs 3.02 days, p = 0.03). Cancer was detected in 8 patients with transurethral prostate resection (10%), of whom 7 are under prostate specific antigen surveillance and 1 received radical radiotherapy. Mean long-term followup was 258 days (range 82 to 884). Prostate vaporization and transurethral prostate resection were equally effective at followup, as evidenced by changes in maximum urine flow, International Prostate Symptom Score, quality of life score and post-void residual urine.

CONCLUSIONS

The 2 operations are highly effective in experienced hands. PlasmaKinetic prostate vaporization resulted in less postoperative bleeding and a slightly shorter hospital stay. The lack of a histological specimen with this version of PlasmaKinetic prostate vaporization may mean that clinically significant cancers are missed.

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.

Validation of the ethanol breath test and on-table weighing to measure irrigating fluid absorption during transurethral prostatectomy

OBJECTIVE

To determine the agreement between on-table weighing and the ethanol breath test in measuring the fluid absorption of patients during transurethral prostatectomy (TURP), and to assess the practicality of on-table weighing in the clinical setting.

PATIENTS AND METHODS

The absorption of irrigating fluid by the patient during TURP can lead to adverse sequelae, including cardiac stress. Despite modern techniques irrigant may still be absorbed and therefore methods to detect absorption are important. Most methods are impractical or inaccurate, but the expired ethanol technique and continuous on-table weighing are more promising. TURP was undertaken in 44 men (mean age 71 years) using continuous flow 1.5% glycine/1% ethanol as the irrigating solution. Intraoperative irrigant absorption was calculated by the ethanol breath test, using published formulae. Absorption measured by the weighing machine was calculated as (weight gain + blood loss - fluid given), and blood loss by the Hemocue method.

RESULTS

The mean (sd) resected weight was 23 (14) g at a mean resection rate of 0.74 g/min. The mean (range) absorption using the balance was 456 (- 343 to 2486) mL, and using the ethanol breath test was 435 (44-2750) mL, with the mean of the differences being - 17 mL, with a 95% confidence interval (CI) of - 81 to -40, the 95% limits of agreement being - 389 to 356 mL (95% CI - 458 to - 337 and 297 to 418 mL).

CONCLUSIONS

Both methods are comparable and measure irrigating fluid absorption to levels of accuracy that are useful clinically. Either method could (and should) be used in routine practice.

Monitoring of irrigation fluid absorption during percutaneous nephrolithotripsy: the use of 1% ethanol as a marker

This study was performed in 32 ASA I patients undergoing percutaneous nephrolithotripsy under general anaesthesia, using absorption of 1% ethanol as a marker to monitor irrigation fluid absorption. Various parameters of fluid absorption were studied and compared, including irrigation fluid volume, irrigation time, total volume of irrigation fluid absorbed and the rate of irrigation. The amount of irrigant used vs. the volume absorbed and the volume absorbed vs. total irrigation time were observed. Fluid absorption occurred in 78% of patients, and 28% absorbed volumes in excess of 1 l. The mean volume of fluid absorbed was 696.7 ml. The maximum fluid absorption was observed when the irrigation fluid volume, total irrigation time and irrigation rate exceeded 10 l, 30 min and 200 ml.min(-1), respectively. In conclusion, this study has shown 1% ethanol to be a safe, simple and cost-effective marker of fluid absorption during percutaneous nephrolithotripsy associated with minimal adverse effects.

Psychiatric disorders after transurethral resection of the prostate

Three men in their 70s had long-term changes in mood and personality dating from immediately after transurethral prostatectomy. Focal abnormalities in the brain were not detected. The possibility of psychiatric as well as cardiovascular sequelae from this operation deserves investigation.