Cardiovascular performance and core temperature during transurethral prostatectomy

Warming of intravenous and irrigation fluids for preventing inadvertent perioperative hypothermia

BACKGROUND

Inadvertent perioperative hypothermia (a drop in core temperature to below 36°C) occurs because of interference with normal temperature regulation by anaesthetic drugs, exposure of skin for prolonged periods and receipt of large volumes of intravenous and irrigation fluids. If the temperature of these fluids is below core body temperature, they can cause significant heat loss. Warming intravenous and irrigation fluids to core body temperature or above might prevent some of this heat loss and subsequent hypothermia.

OBJECTIVES

To estimate the effectiveness of preoperative or intraoperative warming, or both, of intravenous and irrigation fluids in preventing perioperative hypothermia and its complications during surgery in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Issue 2), MEDLINE Ovid SP (1956 to 4 February 2014), EMBASE Ovid SP (1982 to 4 February 2014), the Institute for Scientific Information (ISI) Web of Science (1950 to 4 February 2014), Cumulative Index to Nursing and Allied Health Literature (CINAHL) EBSCOhost (1980 to 4 February 2014) and reference lists of identified articles. We also searched the Current Controlled Trials website and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomized controlled trials or quasi-randomized controlled trials comparing fluid warming methods versus standard care or versus other warming methods used to maintain normothermia.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from eligible trials and settled disputes with a third review author. We contacted study authors to ask for additional details when needed. We collected data on adverse events only if they were reported in the trials.

MAIN RESULTS

We included in this review 24 studies with a total of 1250 participants. The trials included various numbers and types of participants. Investigators used a range of methods to warm fluids to temperatures between 37°C and 41°C. We found that evidence was of moderate quality because descriptions of trial design were often unclear, resulting in high or unclear risk of bias due to inappropriate or unclear randomization and blinding procedures. These factors may have influenced results in some way. Our protocol specified the risk of hypothermia as the primary outcome; as no trials reported this, we decided to include data related to mean core temperature. The only secondary outcome reported in the trials that provided useable data was shivering. Evidence was unclear regarding the effects of fluid warming on bleeding. No data were reported on our other specified outcomes of cardiovascular complications, infection, pressure ulcers, bleeding, mortality, length of stay, unplanned intensive care admission and adverse events.Researchers found that warmed intravenous fluids kept the core temperature of study participants about half a degree warmer than that of participants given room temperature intravenous fluids at 30, 60, 90 and 120 minutes, and at the end of surgery. Warmed intravenous fluids also further reduced the risk of shivering compared with room temperature intravenous fluidsInvestigators reported no statistically significant differences in core body temperature or shivering between individuals given warmed and room temperature irrigation fluids.

AUTHORS' CONCLUSIONS

Warm intravenous fluids appear to keep patients warmer during surgery than room temperature fluids. It is unclear whether the actual differences in temperature are clinically meaningful, or if other benefits or harms are associated with the use of warmed fluids. It is also unclear if using fluid warming in addition to other warming methods confers any benefit, as a ceiling effect is likely when multiple methods of warming are used.

The effectiveness of strategies for the management and/or prevention of hypothermia within the adult perioperative environment: systematic review

BACKGROUND

Inadvertent hypothermia is common in patient's undergoing surgical procedures. Hypothermia within the perioperative environment may have many undesired physiological effects that are associated with significant postoperative morbidity. Patient's temperature drops to below 35°C during the first hour of anaesthesia because of impaired thermoregulatory mechanism and patient getting cold in the operating theatre. For this reason, health care professionals working in the perioperative environment need to know what are the most effective strategies for treating or preventing hypothermia to improving patient outcomes following surgical procedures. However, to date there has been no systematic review of effectiveness with high quality randomised controlled trials to identify effective strategies for the prevention and/or management of hypothermia in the perioperative environment.

OBJECTIVE

The objective of this systematic review was to identify the most effective strategies for the prevention and/or management of hypothermia in the intraoperative and postoperative phases of surgical care.

DATA SOURCES

A comprehensive search was undertaken on electronic databases from their inception to October 2008, including Cochrane library, MEDLINE, PubMed, CENTRAL, CINAHL, Current contents connect, DARE, Dissertations Abstract International, EMBASE, Scopus, and TRIP. The search was restricted to English language.

REVIEW METHODS

Randomised controlled trials or clinical controlled trials were sought, which evaluated the effectiveness of active or passive warming techniques in the prevention and/or treatment of inadvertent hypothermia. Critical appraisal of study quality was undertaken using Joanna Briggs Institute critical appraisal instruments. Data extraction was via the Joanna Briggs Institute standard data extraction form for evidence of effectiveness.

RESULTS

Eighteen studies with a combined 1451 patients were included. The results were classified into three categories with a further sub classification within the active warming techniques category.Forced air warming was effective in maintaining intraoperative normothermia when compared to passive warming, routine thermal care and no form of warming. Forced air warming in pregnant women scheduled for caesarean delivery under regional anaesthesia prevented maternal and foetal hypothermia. In contrast, passive warming with tight elastic bandages wrapped around the legs (passive insulation) in the same patient population had no significant benefits in preventing maternal hypothermia.However, in arthroscopic knee surgery patients, forced air warming did not result in a decrease in the incidence of postoperative shivering indicating that it was not effective or feasible to extend active warming into recovery in this patient population. Forced air warming was effective than circulating water mattress in preventing hypothermia in patients who underwent repair of infrarenal aortic aneurysms. Forced air warming was effective against radiant warming in maintaining intraoperative normothermia in lengthier surgical procedures.Prewarming in different patient populations prevents redistribution hypothermia, especially after one hour of anaesthesia induction. Intravenous and irrigating fluids warmed (38-40°C) to a temperature higher than that of room temperature by different fluid warming devices (both dry and water heated) proved significantly beneficial to patients in terms of stable haemodynamic variables, and higher core temperature (core T) at the end of the surgery (transurethral prostatectomy and orthopaedic surgery). However, prewarming irrigation fluids in knee arthroscopy patients did not prove beneficial in maintaining normothermia.Water garment warmer was significantly (P < 0.05) effective than forced air warming in maintaining intraoperative normothermia in orthotopic liver transplantation patients. Extra warming with forced air compared to routine thermal care was effective in reducing the incidence of surgical wound infections and postoperative cardiac complications, as well as shorten the length of hospital stay.Passive warming with reflective heating blankets or elastic bandages wrapped around the legs tightly were found to be ineffective in reducing the incidence or magnitude of hypothermia. Low-flow anaesthesia with active forced air warming was effective in stabilising patient's core T during surgical procedures when compared to low-flow anaesthesia alone or low-flow anaesthesia with passive insulation.Phenylephrine i.v. infusion resulted in a significantly less reduction in core T after first hour of anaesthesia and patients were warmer until the end of the surgery (minor oral surgery).

CONCLUSION

Active warming with forced air warming units keeps all patients warmer in the intraoperative and postoperative periods. Forced air warming compared with alternate forms of warming reduces the incidence of shivering and wound infections, increases thermal comfort and reduces morbid cardiac events.

IMPLICATIONS FOR PRACTICE

Our review indicates that active warming techniques (forced-air warming) are effective in preventing and managing hypothermia in the perioperative environment and based on the results from the review there are several recommendations to guide clinical practice: IMPLICATIONS FOR RESEARCH: Future research should focus on large, high quality randomised controlled trials looking at long-term clinical outcomes, operating temperature forced-air warming devices (not just maximum set temperature), different body sites and percentage of body coverage area of active warming for efficient management of intraoperative hypothermia.

Is warm temperature necessary to prevent urethral stricture in combined transurethral resection and vaporization of prostate?

OBJECTIVES

To compare the effect of warm and room temperature irrigation solution on the incidence of urethral stricture during combined transurethral resection and vaporization of the prostate (CTURVP). Urethral stricture after transurethral surgery of the prostate is a bothersome complication. Warm irrigation improves the blood flow and might decrease the incidence of urethral stricture compared with the use of room temperature irrigation, which decreases the blood flow in the urethral mucosa, resulting in ischemic injury.

METHODS

The patients who underwent CTURVP were divided into those receiving only room temperature irrigation solution (group 1, 75 patients) or warm irrigation solution with a system maintaining the temperature of the ventral penile skin at about 36 degrees C continuously (group 2, 78 patients). At follow-up, 1, 3, and 6 months later, the International Prostate Symptom Score and peak urine flow rate were evaluated.

RESULTS

The temperature of the ventral penile skin was 20 degrees C and 36 degrees C in groups 1 and 2, respectively. The rate of urethral stricture was 21.3% in group 1 and 6.3% in group 2 at the end of 6 months of follow-up (P = .002).

CONCLUSIONS

The results of our study have shown that maintaining the temperature of the urethra with warm irrigation solution during CTURVP probably decreases the incidence of urethral stricture. The temperature in the urethra could be another important factor in stricture formation after CTURVP.

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

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.

Comparison of hemodynamic profiles in transurethral resection of prostate vs transurethral resection of urinary bladder tumors during spinal anesthesia: a bioimpedance study

STUDY OBJECTIVE

Transurethral resection of prostate (TURP) is more frequently associated with perioperative fluid and electrolyte disturbances than transurethral resection of bladder tumors (TURT) because of irrigating fluid absorption. Because fluid overload may cause hypertension, we compared the patients' intraoperative hemodynamic profiles (including the incidence of hypertension) during TURP vs TURT, both performed during spinal anesthesia, by using the bioimpedance method.

DESIGN

Prospective single-blind study.

SETTING

University hospital.

PATIENTS

80 (40 in each group) men, ASA physical status I and II.

INTERVENTIONS

Patients underwent TURP or TURT surgery with spinal anesthesia.

MEASUREMENTS

Mean arterial pressure, heart rate, cardiac index, and systemic vascular resistance were compared between the 2 groups. A mean arterial pressure greater than 30% from the baseline value was considered as hypertension. Plasma sodium was measured preoperatively, intraoperatively, and postoperatively.

MAIN RESULTS

Transurethral resection of prostate patients received more irrigating fluid (7900 +/- 2310 vs 5650 +/- 21560, P < 0.05) and had a higher calculated volume of fluid absorbed: 638 +/- 60 vs 303 +/- 40 mL for the TURT patients (P < 0.05). Mean arterial pressures were higher with TURP, 30 minutes after the onset of surgery and at the end of the procedure (111 +/- 15 vs 100 +/- 10 and 109 +/- 14 vs 99 +/- 14 mmHg, respectively; P < 0.05). However, there was no hypertension in either group. There were no differences in hemodynamic measurements of hyponatremic vs normonatremic patients. Plasma sodium decreased postoperatively more in the TURP group (140.4 +/- 2.6 mEq/L baseline to 134.1 +/- 3.5 mEq/L, P < 0.05) and was lower postoperatively in the TURP group compared with TURT (134.1 +/- 3.5 vs 137.2 +/- 2.9 mEq/L, P = 0.04).

CONCLUSIONS

Although more irrigating fluid was absorbed in the TURP group, there were no episodes of hypertension in either group.

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.

Topical radiant heating in wound healing: an experimental study in a donor site wound model*

The importance of temperature in the wound-healing process is rapidly being recognised as a novel way in which to manipulate the wound-healing environment. In this study, we aimed to investigate the direct effect of topical radiant heating (TRH), using a novel bandaging system (Warm-Up, Arizant Health care Inc., Eden Prairie MN, USA; Augustine Medical, USA), on wound healing at a physiological and cellular level. Experimental bandages were positioned over split-thickness skin graft donor site wounds of 12 patients undergoing graft harvesting from the anterior thigh. The experimental group (n=6) underwent intermittent heating for 5 hours (three 1-hour heating cycles at 38 degrees C, separated by two 1-hour rest periods), whilst the control group (n=6) received no radiant heating. Physiological blood-flow recordings both in the control group and the topical radiant heat cohort were undertaken using Laser Doppler Imaging (LDI). Skin biopsies were obtained at identical time points, and immunohistochemical analysis was undertaken using antibodies against neutrophils (NP57), lymphocytes (CD3) and macrophages (CD68). We found that TRH significantly increased local dermal blood flow (P<0.001) by up to 100% in both injured and intact skin. Furthermore, this increase in flow was associated with a significant (P<0.05) increase in CD3 immunoreactivity on day 1 postoperatively. This study demonstrates that TRH increases local blood flow and lymphocyte (CD3) extravasation, and we postulate that these changes may enhance local innate immunity within the healing wound environment.

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.

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.

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.

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.