Haemodynamic evidence for cardiac stress during transurethral prostatectomy

Risk of acute myocardial infarction after transurethral resection of prostate in elderly

Background

Benign prostatic hyperplasia is a frequent disease among elderly, and is responsible for considerable disability. Benign prostatic hyperplasia can be clinically significant due to lower urinary tract symptoms that take place because the gland is enlarged and obstructs urine flow. Transurethral resection of the prostate remains the gold standard treatment for patients with moderate or severe symptoms who need active treatment or who either fail or do not want medical therapy. Moreover, perioperative and postoperative surgery complications as cardiovascular ones still occur. The incidence of acute myocardial infarction in patients undergoing transurethral resection of the prostate is controversial. The first studies showed an increase in mortality and relative risk of death from myocardial infarction in transurethral resection of the prostate group vs open prostatectomy but these results are in contrast with more recent data.

Discussion

Given the conflicting evidence of the studies in the literature, in this review we are going to discuss the factors that may influence the risk of myocardial infarction in elderly patients undergoing prostate surgery. We analyzed the possible common factors that lead to the development of myocardial infarction and benign prostatic hyperplasia (cardiovascular and metabolic), the stressor factors related to prostatectomy (surgical and haemodynamic) and the risk factors specific of the elderly population (comorbidity and therapies).

Summary

Although transurethral resection of the prostate is considered at low risk for severe complications, there are several reports indicating that cardiovascular events in elderly patients undergoing this surgical operation are more common than in the general population. Several cardio-metabolic, surgical and aging-related factors may help explain this observation but results in literature are not concord, especially due to the fact that most data derive from retrospective studies in which selection bias cannot be excluded. Subsequently, further studies are necessary to clarify the incidence of acute myocardial infarction in old people.

The effects of irrigation fluid on core temperature in endoscopic urological surgery

AIMS AND METHOD

A prospective observational study of 100 patients undergoing various types of endoscopic urological surgery including transurethral resection of the prostate (TURP), transurethral resection of bladder tumour (TURBT), percutaneous nephrolithotomy (PCNL) and Cystoscopies, was reformed to determine the temperature difference between preoperative and postoperative core temperatures and to determine whether this change was related to the age, weight, type of anaesthetic, operation duration, type of operation, amount of irrigant fluid used and whether warming the fluid to 370C made a difference to the degree of temperature change. All the above variables were recorded for each patient as well as the preoperative and postoperative temperatures. Statistical analysis was carried out using SPSS.

RESULTS

The mean age was 64 years and the mean weight was 75kg in the study. Seventy-six patients had a general anaesthetic while 24 had a spinal anaesthetic. The study included 29 TURPs, 10 TURBTs, six PCNLs and 55 Cystoscopies. Age and type of anaesthetic did not correlate significantly with temperature change. As weight increased patients tend to preserve their core temperature more efficiently. The highest degree of temperature drop was in the PCNL group. There was a significant relationship between the duration of operation and temperature drop (p<0.05) as well as the amount of irrigation fluid used (p<0.05). Average temperature drop for patients who underwent irrigation with fluid at room temperature (n=43) was 1.37 degrees C and 0.95 degrees C for those whose fluids were warmed to body temperature (n=57). This difference was statistically significant (p=0.03).

CONCLUSIONS

There is a drop in temperature in patients undergoing most endoscopic operations on the GU tract and this appears to be multifactorial in origin, relating significantly to weight, amount of irrigation fluid used, type and duration of operation. Warming irrigant fluid to body temperature appears to significantly reduce the degree of temperature drop with consequent potential benefit.

Effect of warm intravenous and irrigating fluids on body temperature during transurethral resection of the prostate gland

Background

Transurethral resection of the prostate gland with irrigation fluid at room temperature leads to perioperative hypothermia which could give rise to adverse cardiovascular events in the perioperative period. The use of isothermic irrigation fluid reduces but does not eliminate this risk. Routine use of warm intravenous fluids along with isothermic irrigation had not been documented. This study set out to investigate the effect of the use of warm intravenous fluid together with isothermic irrigation fluid on the body temperature in patients undergoing transurethral resection of the prostate gland.

Methods

One hundred and twenty consented patients with obstructing benign prostatic hyperplasia were randomly assigned to one of 3 groups. Group 1 received irrigation and intravenous fluids at room temperature, group 2 received warmed irrigation fluid at 38°C along with intravenous fluid at room temperature while group 3 patients received warmed irrigation fluid and warmed intravenous fluids at 38°C. Their perioperative body temperature changes were monitored, analyzed and compared.

Results

The mean decrease in body temperature at the end of the procedure was significantly greater in group 1 (0.98 ± 0.56°C) than in group 2 (0.42 ± .21°C) (p < 0.001). Significantly more patients in group 1 also experienced shivering. However, in group 3, there was no significant change in the mean body temperature (p > 0.05) and none of them felt cold or shivered.

Conclusion

It is concluded that the use of isothermic irrigation fluid together with warm intravenous fluids during TURP prevents the occurrence of perioperative hypothermia.

Trial registration number

CCT-NAPN-15944

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.

Acute myocardial infarction after transurethral resection of the prostate

Several factors inherent in the transurethal resection of the prostate (TURP) procedure may impose stress on the cardiovascular system. The risk of acute myocardial infarction (AMI) is usually considered to be low but has still been an issue during the last 10 years. Interestingly, the concerns are focused on a possible adverse effect of TURP on the long-term risk of AMI and on survival. Selection bias has been a problem in many of the published studies, however. Co-morbidity is also difficult to handle when the follow-up lasts for several years, in particular since benign prostatic enlargement alone seems to be associated with an increased risk of cardiovascular disease.

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.

Haemodynamic changes detected during open prostatectomy and transurethral resection for benign prostatic hyperplasia

To detect possible intraoperative haemodynamic differences, 60 patients undergoing transurethral (n = 18) or open prostatectomy (n = 42) for benign prostatic hyperplasia were evaluated. The same type of general anaesthesia was used in the two groups. Data, including temperature and cardiac output, were collected at five standard times during the procedures. No significant differences were found between the two groups. However, in all patients, irrespective of the operation, significant decreases in cardiac output and increases in systemic resistance occurred during surgery. Body temperature showed a mild, insignificant decrease, which may play a role in determining the mild haemodynamic derangement observed in all patients. Our patients subjected to open prostatectomy and transurethral resection presented the same kind of haemodynamic derangement, with no significant differences. Therefore it seems unlikely that the kind of surgery could play a relevant role in the late mortality rate of these patients.

Incidence of perioperative myocardial ischemia in TURP patients

STUDY OBJECTIVE

To determine the incidence of new episodes of myocardial ischemia in patients undergoing transurethral resection of the prostate (TURP).

DESIGN

Prospective, nonrandomized study.

SETTING

Veterans Administration medical center.

PATIENTS

39 patients undergoing elective TURP.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Myocardial ischemia was detected with a 3-channel ambulatory ECG recorded. The ambulatory ECG recorder was applied preoperatively and removed when the patient left the recovery room. New myocardial ischemia was defined as a 1 mm or greater ST depression or a 2 mm or greater ST elevation from baseline, lasting for 1 minute or longer in at least one lead at the J point plus 60 msec unless this point fell within the T wave, in which case the J point 40 msec or greater was used. ST changes consistent with myocardial ischemia were confirmed by a cardiologist blinded to the patient's clinical course. Seven of 39 TURP patients (18%) had ST segment changes indicative of new myocardial ischemia. These seven patients had more prostate tissue resected and more blood loss than the 32 patients who did not have any myocardial ischemia (p < 0.05).

CONCLUSIONS

Patients undergoing TURP have an 18% incidence of myocardial ischemia. Patients undergoing TURP with more prostate tissue resected and greater blood loss are at increased risk for perioperative myocardial ischemia.

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

OBJECTIVE

To design a practical system for non-invasively monitoring fluid balance during transurethral resection of the prostate (TURP) and other endoscopic procedures.

MATERIALS AND METHODS

Load cell transducers are incorporated into a platform placed under the operating table. Output is passed to a digital weighmeter and then to a portable computer. The raw data is filtered using software written by the authors (CAL) and the output displayed both numerically and graphically on the computer screen. The device was tested under laboratory conditions and then assessed in the clinical setting.

RESULTS

The device proved stable in both the laboratory and clinical settings. Examples of the common patterns generated during TURP are presented. The prototype has been used routinely in our practice to warn the surgeon and anaesthetist of fluid overload and has been used to monitor fluid balance in several studies.

CONCLUSIONS

This instrument provides a practical method of monitoring total fluid balance during TURP. It can be used with either general or regional anaesthesia and provides information not otherwise available. It provides an early warning of significant changes in total fluid balance, particularly irrigant fluid absorption. Use of this device serves to prevent development of the TUR syndrome, a potentially fatal complication of endoscopic surgery. Our ultimate aim is to produce a refined version that is simple, compact and cheap enough to be used routinely in all urological theatres. The cost of a single episode of intensive care for a patient developing iatrogenic complications from irrigant absorption would offset the cost of such a device.

Body heat transfer during hip surgery using active core warming

The purpose of this study was to evaluate the effect of core warming on heat redistribution from the core to the periphery as manifested by changes in core, mean skin temperature and mean body heat, investigated in a group of 30 patients undergoing total hip replacement. The control group (n = 10) had no active warming. Core warming was achieved in the humidifier group (n = 10) by using humidified and warmed gases at 40 degrees C, whilst in the oesophageal group (n = 10), an oesophageal heat exchanger was used to achieve active warming. Operating room temperature and relative humidity was standardised. Aural canal and skin temperatures (15 sites) were measured before induction of anaesthesia, at the end of surgery and one hour of recovery after anaesthesia. Mean skin temperatures were calculated for a weighted four and unweighted 15 points, and mean body heat were calculated to quantify the distribution of body heat. Core temperature decreased in the control and the oesophageal groups, but not in the humidifier group at the end of surgery; by mean values +/- SD of 1.9 degrees C +/- 0.6, 1.2 degrees C +/- 0.6 and 0.4 degree C +/- 0.2 degree C, respectively (P < 0.01). Mean skin temperature (MST15) decreased in the control group by 1.0 degree C +/- 1.0, but not in the actively warmed groups where the mean increased by 0.1 degree C +/- 1.4 and 0.2 degree C +/- 0.2 in the oesophageal and humidifier groups, respectively (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Prostate disease: management options for the primary healthcare team. Report of a working party of the British Prostate Group

The prostate gland has attracted a remarkable increase in interest in the past few years. The two most common diseases of this gland, benign prostatic hyperplasia and carcinoma of the prostate, have been brought into greater prominence by new diagnostic methods, public interest, and a wider choice of surgical and non-surgical treatments. Uncertainty about the significance of these changes has occurred because of the rapidity of change, the profusion of statements, opinions and promotions, and the relatively little guidance available from the profession. Ten urologists and two general practitioners have reviewed the relevant evidence about these two prostate diseases and the newer diagnostic methods; their conclusions are summarised here. Management options and guidance on clinical practice are also discussed. Because of a number of unresolved diagnostic and management issues, detailed requirements for practice guidelines have not been specified.

Cardiovascular performance and core temperature during transurethral prostatectomy

Hemodynamic performance and core temperature were recorded during transurethral prostatectomy in 52 patients who were stratified according to cardiac symptom score and then randomized to undergo standard (31) or isothermic (21) transurethral prostatectomy. During the standard procedure ambient temperature (21C) irrigant was used, while during isothermic prostatectomy warmed irrigant at 38C was used to prevent heat loss from the bladder, and a warming blanket and humidifying filter were used to decrease cutaneous and respiratory heat loss. Core temperature decreased by a mean of 0.8C (95% confidence interval -0.9 to -0.7) during standard transurethral prostatectomy and by 0.27C (-0.4 to -0.15) during the isothermic procedure. The standard prostatectomy group showed a significant hemodynamic response consisting of increased mean arterial pressure (p < 0.0002), increased index of systemic vascular resistance (p < 0.0001), bradycardia (p < 0.02), and decreased Doppler indexes of stroke volume (p < 0.005) and cardiac output (p < 0.001). The isothermic transurethral prostatectomy group was hemodynamically stable. These differences between the groups suggest that rapid central cooling exerted a significant effect on perioperative hemodynamic performance during transurethral prostatectomy.

ECG and cardiac enzymes after glycine absorption in transurethral prostatic resection

The electrocardiogram (ECG) was recorded and the serum levels of creatine kinase (CK), aspartate transaminase (ASAT) and prostatic acid phosphatase (PAP) was measured in 22 patients undergoing transurethral resection of the prostate (TURP) under spinal or epidural anaesthesia. The irrigating fluid consisted of 1.5% glycine and 1% ethanol, and absorption of the fluid was monitored by detection of alcohol in the expired breath. The results show that nine of the 11 patients (82%) who absorbed more than 1,000 ml of irrigating fluid had developed ECG changes 24 h after the operations. The most common alteration was depression of the T wave. This sign was only seen in one (9%) of the patients who absorbed none or very small amounts of irrigating fluid (P < 0.001). The serum activity of CK and ASAT increased in five patients who also developed ECG changes, and the highest values were recorded 24 h after TURP. The CK-MB isoenzyme was detected in 85% of the samples with elevated total CK, but the criteria for myocardial infarction were never fulfilled. In contrast, PAP increased in all patients and the highest level occurred at the end of TURP. The activity-time profiles suggest that CK and ASAT entered the circulation by a mechanism different from that of PAP. We conclude that absorption of glycine solution during TURP is frequently followed by nonspecific ECG signs of altered cardiac function and also that the serum activities of CK and ASAT increase in some of these patients.

Laparoscopic irrigation using a prewarmed pressurized system

An automatic pressure infusion system equipped with a fluid warmer has been developed for rapid intravenous infusion of homeothermic fluids. The use of this system for irrigation during operative laparoscopy provides the surgeon with the ability to irrigate at a relatively high flow while avoiding the hypothermic effects of irrigation with cool fluids.

Haemodynamic effects of transurethral prostatectomy

Thoracic bio-impedance cardiography was used to study the haemodynamic changes in 28 patients undergoing transurethral prostatectomy (TURP) under either general or spinal anaesthesia. Cardiac output and mean arterial pressure fell with induction of general anaesthesia, whilst mean arterial pressure and systemic vascular resistance fell with induction of spinal anaesthesia. The transthoracic fluid index fell during resection under general anaesthesia, but no significant haemodynamic changes were seen during resection under either anaesthetic. This study suggests that resection has no specific adverse haemodynamic consequences. Spinal anaesthesia may produce less haemodynamic disturbance than general anaesthesia in patients undergoing TURP and formal comparison of the 2 techniques seems necessary.

Intra-operative myocardial ischaemia detected by biplane transoesophageal echocardiography during transurethral prostatectomy

Recent studies have shown an increased late mortality rate due to cardiovascular causes after transurethral compared with open prostatectomy. This has been linked to the demonstration of haemodynamic changes during transurethral prostatectomy, which may cause ischaemic myocardial injury. We used transoesophageal echocardiography (currently the most sensitive modality for detecting myocardial ischaemia) to study 26 patients during prostatectomy under general anaesthesia. Evidence of myocardial ischaemia (as shown by the development of new regional wall motion abnormalities of the left ventricle) occurred in 4 of 22 patients during transurethral and in 3 of 4 patients during retropubic prostatectomy. An intra-operative fall in systolic as well as diastolic blood pressure occurred in 21 of 22 patients during the transurethral procedure and in all 4 patients during retropubic prostatectomy. The duration of anaesthesia and the operation, and the intra-operative blood loss did not differ significantly between patients with and without evidence of intra-operative myocardial ischaemia. However, the maximum intra-operative fall in systolic and diastolic blood pressure, as well as the mass of the prostatic tissue removed, were significantly greater in patients with than in those without evidence of intra-operative myocardial ischaemia, suggesting that the latter may be related to the extent of surgery and the degree of intraoperative hypotension. In this study, 7 of 26 patients (27%) showed evidence of myocardial ischaemia during prostatectomy. However, it remains difficult to explain why intra-operative myocardial ischaemia should result in an increased cardiovascular mortality rate several years after the operation.