***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Intradialytic hypotension ( IDH ) is a morbid complication of hemodialysis ( HD ) . Both midodrine , an oral selective alpha1 agonist , and cool dialysate have been reported as useful therapies for this problem . We performed this prospect i ve crossover study to compare the efficacy of these two therapies , alone and in combination , for IDH . The study consisted of a control phase and three treatment phases : midodrine phase ( 10 mg oral dose pre-HD ) , cool dialysate phase ( 35.5 degrees C ) , and combination therapy phase ( midodrine , 10 mg , and dialysate temperature , 35.5 degrees C ) . Each phase consisted of nine consecutive HD treatments . Eleven patients ( six men , five women ; mean age , 67.5 years ) with known symptomatic IDH were studied . This cohort was followed up in terms of blood pressure measurements ( pre-HD blood pressure , lowest intradialytic blood pressure , post-HD blood pressure ) , weights , laboratory values , and interventions for IDH . The lowest intradialytic blood pressures were significantly better with midodrine and cool dialysate compared with the control phase ( systolic blood pressure [ SBP ] , 103.9 + /- 4.1 [ mean + /- st and ard error of the mean ] and 102.6 + /- 2.9 v 90.6 + /- 2.5 mm Hg , respectively ; P < 0.001 ) , as were the post-HD blood pressures ( SBP , 116.9 + /- 4.0 and 118.2 + /- 3.5 v 109.0 + /- 2.1 mm Hg ; P < 0.01 ) . In addition , the lowest intradialytic blood pressures were significantly better with the combination phase compared with the control phase ( SBP , 103.7 + /- 4.2 v 90.6 + /- 2.5 mm Hg ; P < 0.001 ) , as were the post-HD blood pressures ( SBP , 122.1 + /- 4.6 v 109.0 + /- 2.1 mm Hg ; P < 0.01 ) . There was a significant reduction in the number of nursing interventions performed and volume of saline infused for IDH with midodrine and cool dialysate compared with control . There was a trend toward amelioration of hypotensive symptoms with both therapies . Laboratory values , including Kt/V , did not change significantly with either midodrine or cool dialysate . This prospect i ve study shows that both midodrine and cool dialysate are effective therapies for symptomatic IDH .  There does not seem to be additional benefit when these two therapies are used in combination Cool dialysate and midodrine have been used successfully to treat intradialytic hypotension ( IDH ) in the end-stage renal disease population . However , the exact mechanisms by which these interventions improve hemodynamic stability are not well known . We undertook a study to evaluate the effect of these modalities on intradialytic hemodynamics in patients with documented dialysis-associated hypotension . We used the ultrasound dilution technique to measure cardiac output ( CO ) , central blood volume ( CBV ) , and peripheral vascular resistance ( PVR ) in these patients . The study was performed in two phases . Phase 1 consisted of control ( 1A ) and cool dialysate ( 1B ) studies , whereas phase 2 consisted of control ( 2A ) and midodrine ( 2B ) studies . CO , CBV , and PVR were measured 30 minutes after the initiation of hemodialysis ( HD ) and 30 minutes before the termination of HD using the HD01 monitor . Blood pressure was measured pre-HD and post-HD . Fourteen patients with documented IDH completed the study .  CO and CBV were significantly more preserved in the cool dialysate and midodrine phases compared with control phases . PVR increased in all phases of the study . Declines in mean arterial pressures from pre-HD to post-HD were less with cool dialysate versus control and midodrine versus control . Ultrafiltration volumes were not significantly different between phases . Cool dialysate and midodrine appear to improve intradialytic hemodynamics in patients with dialysis-associated hypotension , mainly through the preservation of CBV and CO , rather than significantly elevating PVR Cool temperature dialysis ( CTD ) has been shown to sharply decrease the frequency of intradialytic hemodialysis hypotension , but the mechanism of this hemodynamic protection is unknown . Therefore , we performed two-dimensional echocardiographic studies of left ventricular contractility in six stable hemodialysis patients before and after hemodialysis at 37 degrees C ( RTD ) and 35 degrees C ( CTD ) .  Left ventricular function was assessed by plotting the rate-corrected velocity of circumferential fiber shortening ( Vcfc ) against end-systolic wall stress ( sigma es ) at four different levels of afterload . Linear regression was used to calculate Vcfc at a common afterload of 50 g/cm2 . Changes in weight and dialysis parameters were similar following RTD and CTD .  Mean arterial pressure and heart rate did not change significantly following RTD or CTD . The Vcfc - sigma es relation was shifted upward in each patient after CTD , indicating increased contractility as compared to RTD or pre-dialysis baseline . Pre-dialysis Vcfc at an afterload of 50 g/cm2 was similar during RTD and CTD ( 0.94 + /- 0.24 circ/sec vs. 0.92 + /- 0.22 circ/sec ) . Postdialysis Vcfc at an afterload of 50 g/cm2 was significantly higher for CTD than for RTD ( 1.13 + /- 0.29 circ/sec vs. 0.98 + /- 0.30 circ/sec , P = 0.0004 ) . Thus , cool temperature dialysis increases left ventricular contractility in hemodialysis patients , which may be a potential mechanism whereby hemodynamic tolerance to the dialysis procedure is improved BACKGROUND The relationship between blood pressure ( BP ) and mortality in hemodialysis patients has remained controversial . Some studies suggested that a lower pre- or postdialysis BP was associated with excess mortality , while others showed poorer outcome in patients with uncontrolled hypertension . We conducted a multicenter prospect i ve cohort study to evaluate the impact of hemodialysis-associated hypotension on mortality . METHODS We recruited 1244 patients ( 685 males ; mean age , 60 + /- 13 years ) who underwent hemodialysis in 28 units during the two-year study period beginning in December 1999 .  Pre- , intra- , and postdialysis BP , and BP upon st and ing soon after hemodialysis , were measured in all patients at entry . Logistic regression analysis was used to assess the effect on mortality of pre- , intra- , and postdialysis BP , a fall in BP during hemodialysis  , and a fall in BP upon st and ing soon after hemodialysis .  RESULTS During the study period , 149 patients died . Logistic models identified the lowest intradialysis systolic blood pressure ( SBP ) and degree of fall in SBP upon st and ing soon after hemodialysis as significant factors affecting mortality , but not pre- or postdialysis SBP and diastolic BP . The adjusted odds ratio for death was 0.79 ( 95 % CI 0.64 - 0.98 ) when the lowest intradialysis SBP was analyzed in increments of 20 mm Hg , and was 0.82 ( 95 % CI 0.67 - 0.98 ) when the fall in SBP upon st and ing soon after hemodialysis was analyzed in increments of 10 mm Hg . CONCLUSION These results suggest that intradialysis hypotension and orthostatic hypotension after hemodialysis are significant and independent factors affecting mortality in hemodialysis patients Use of cool dialysate is associated with increased intradialytic blood pressure , but the hemodynamic mechanism is unknown . Whether changes in dialysate temperature affect muscle blood flow , which may the alter the degree of urea compartmentalization , also is unknown . We measured hemodynamics and blood and dialysate-side urea kinetic indices in nine hemodialysis patients during two cool ( 35.0 degrees C ) versus two warm ( 37.5 degrees C ) dialysate treatments . The % change in mean arterial pressure was different when using the cool ( + 6.5 + /- 9.7 mm Hg ) versus the warm ( -13.4 + /- 3.6 ) dialysate ( P < 0.01 ) , despite comparable amounts of fluid removal . Percent changes in cardiac output were similar with the two dialysates , and thus the blood pressure effect was due primarily to changes in total peripheral resistance ( % delta TPR , cool + 26 + /- 13.6 , warm + 8.6 + /- 14.5 ; P < 0.02 ) . During cool dialysate use tympanic membrane temperature changed by -0.51 + /- 0.23 degree C , whereas body temperature increased by 0.52 + /- 0.14 degree C during use of warm dialysate . Measured urea recovery normalized to the predialysis urea nitrogen concentration was similar with the two treatments : cool 31.3 + /- 0.039 liter-1 ; warm 29.7 + /- 0.021 ; P = NS . In a second study , post-dialysis urea rebound values from 15 seconds to 30 minutes , expressed as the percent of the post-dialysis SUN , were similar after the two treatments : cool 11.79 + /- 1.4 ; warm 12.21 + /- 2.27 , P = NS . ( ABSTRACT TRUNCATED AT 250 WORDS Treatment of intradialytic hypotension ( IDH ) in the end-stage renal disease population has been a difficult task for nephrologists caring for these patients . The presence of multiple pathogenic factors contributes to hemodynamic instability and explains why therapies that modulate only a specific aspect of the problem are only partially effective . Cool dialysate ( 34.5 degrees C to 35.5 degrees C ) and midodrine may provide hemodynamic stability through an increase in peripheral vascular resistance , whereas high dialysate calcium concentration ( HDCa ; 3.5 mEq/L ) improves intradialytic blood pressure through preservation of cardiac output . Theoretically , the combination of these two types of therapies might further reduce the frequency and severity of hypotension during hemodialysis ( HD ) . We undertook a study to evaluate the effect of HDCa added to midodrine and /or cool dialysate in the treatment of patients with severe IDH . Twenty-eight patients met the entry criteria , and 23 patients completed the prospect i ve crossover study . Five patients dropped out of the study secondary to hypercalcemia . The addition of HDCa significantly improved post-HD mean arterial pressure ( MAP ; 95.6 + /- 12.7 versus 90.8 + /- 12.5 mm Hg ; P = 0.002 ) . The decreases in MAP from pre-HD to lowest intradialytic ( 16.3 + /- 8.2 versus 20.6 + /- 10.0 mm Hg ; P = 0.009 ) and pre-HD to post-HD ( 2.0 + /- 8.5 versus 8.15 + /- 10.8 mm Hg ; P = 0.002 ) were significantly reduced with HDCa compared with low dialysate calcium . However , there were no significant improvements in symptoms of or interventions for IDH . Thus , it appears that the addition of HDCa to midodrine and /or cool dialysate further improves blood pressure in patients with IDH . However , this therapy did not reduce symptoms or interventions required for IDH . In addition , hypercalcemia complicated this therapy in 22 % of the patients BACKGROUND The present study was performed to assess the role of the extracorporeal blood temperature in the disparate cardiovascular response between isolated ultrafiltration and combined ultrafiltration-haemodialysis . METHODS In twelve stable dialysis patients ( 21 - 77 years ) , blood pressure and heart rate ( Finapres ) as well as forearm vascular resistance and venous tone ( strain-gauge plethysmography ) were measured during 1-h isolated ultrafiltration and 1-h combined ultrafiltration-haemodialysis ( bicarbonate , sodium 141 mmol/l ) at a fixed ultrafiltration rate of 0.91 l/h . The sequence of both treatment modalities was r and omly defined within each patient . Serving as his or her own control , each patient was studied at two different dialysate temperatures : 37.5 and 35.0 degrees C. RESULTS At a dialysate temperature of 35.0 degrees C extracorporeal blood cooling during combined ultrafiltration-haemodialysis was comparable to isolated ultrafiltration . The cardiovascular response in isolated ultrafiltration was characterized by a significant increase in both forearm vascular resistance and venous tone , while heart rate even decreased . As a result , blood pressure remained unchanged or even increased . In contrast , during combined ultrafiltration-haemodialysis at a dialysate temperature of 37.5 degrees C the increase in forearm vascular resistance was only small and insignificant , while venous tone decreased significantly . Heart rate tended to 
    Output:
    
Reducing the temperature of the dialysate is an effective intervention to reduce the frequency of IDH and does not adversely affect dialysis adequacy .
This applies to the fixed reduction of dialysate temperature and BTM .
It remains unclear as to what extent cool-temperature dialysis causes intolerable cold symptoms during dialysis .