Peritoneal Equilibration Yasuki Hashimoto, Akira Mima Test˚at Home

15 Pages·2002·3.74 MB·English

Advances in Peritoneal Dialysis, Vol. 18, 2002
Peritoneal Equilibration
Test˚at Home
Yasuki Hashimoto, Akira Mima
The peritoneal equilibration test (PET) has been Introduction
widely used as a standardized means for estimating As popularized by Twardowski, the peritoneal equili-
solute transport. However, the procedure is rather bration test (PET) has been introduced as a conve-
complex, and patients must spend more than half a nient method by which an individual patient s
day in the hospital. The fast PET is an alternative peritoneal membrane transport function may be char-
method, but the results are not reliable in patients acterized and compared to population norms (1,2). The
whose peritoneal catheters drain poorly. data obtained from the PET provide valuable qualita-
We postulated that patients could perform the tive and quantitative information on peritoneal func-
PET at home if educated well about the procedure. tioninformation that has contributed greatly to
To that purpose, we prepared three types of visual individualizing the dialysis prescription and evaluat-
aids that introduce the PET procedure: a VCR tape, ing the reasons behind inadequate dialysis.
a DVD disc, and a brochure with photographs. Repeat PETs may be recommended to document
Equilibration tests were performed using the changes in membrane characteristics and to predict
twin-bag system. For marking fluid level indicator membrane failure associated with encapsulating peri-
lines (200˚mL and 10˚mL), patients are given a guide tonitis sclerosis (3). However, the procedure is rather
sheet on which the fresh dialysate bag is placed. complex and patients must spend more than half a day
After an 8-˚to 12-hour overnight dwell, the dwelled in the hospital. Those problems sometimes become
dialysate is drained completely into the empty bag. major obstacles to regular PET testing. Because of
Immediately after the patient infuses 2˚L of fresh 2.5% labor limitations in the medical facility or time limi-
glucose dialysis solution, 200˚mL of that solution is tations of patients, tests sometimes fail to be performed
drained into the bag on which the two fluids levels on regular basis.
were previously marked. After mixing, about 190˚mL A fast equilibration test (fast PET) is an alterna-
of the dialysate is re-infused, and the remaining tive method (4). The patient initiates the equilibration
10˚mL (the amount indicated by a guide mark at the test exchange at home and comes to the clinic for sam-
corner) is left within the bag. After a 4-hour dwell, pling of dialysate and blood at the 4-hour dwell time.
the dialysate is completely drained into another Although the fast PET is less expensive and less time-
twin-bag. consuming, the results are not reliable in patients
A standard PET was also performed on a differ- whose peritoneal catheters drain poorly.
ent day, and the data were compared with those from We developed a modified PET method (the home
the home PET. Significant correlations were seen in PET), performed principally by patients in their homes,
D/D and in drain volume between the home PET that provides accurate results. We postulated that pa-
0
and the standard PET (n˚= 10; D/D : 0.385˚± 0.054 tients could perform the PET at home if they were
0
vs. 0.371˚± 0.052 respectively, r˚= 0.872, p˚= 0.0004; educated about the procedure and understood it thor-
drain volume: 2340˚± 123˚mL vs. 2372˚± 90˚mL re- oughly. For that purpose, we prepared three types of
spectively, r˚= 0.788, p˚= 0.0048). visual aids that show the PET procedure: a VCR tape,
We conclude that the home PET is a clinically a DVD disc, and a brochure with color photographs.
useful alternative to the standard PET, saving time We thought that the incidence of sampling errors could
and labor while maintaining accuracy. be reduced by giving the patients detailed visual
instructions.
Key words
Peritoneal equilibration test, PET, home PET Patients and methods
Peritoneal equilibration tests were performed in
From: Shizuoka City Hospital, Shizuoka, Japan. 10˚case studies where twin-bag systems were used
82 Hashimoto and Mima
(Table˚I). At our outpatient clinic, the patients were The home PET procedure is based on the stan-
given visual aids (a VCR tape, a DVD disc, and a dard PET, but blood and dialysate sampling at hour˚2
brochure with photographs, all of which showed the are omitted for patient convenience. The PET category
home PET procedure) and a form for recording ex- is calculated from drain volume and from the dialy-
change time and drain volume (Figure˚1). sate-to-instilled ratio (D/D ) of glucose at hour˚4.
0
To ascertain the efficacy of visual aids, verbal in-
structions at the outpatient clinic were minimal. In Home PET procedure
the cases of two older patients who were not able to Figure˚2 shows the home PET procedure.
perform the tests themselves, a family member per- For marking fluid-level indicator lines (200˚mL
formed the procedure for the patient instead (Table˚I). and 10˚mL), patients receive a guide sheet on which
the fresh dialysate bag (2˚L 2.5% dextrose bag) is
TABLE I Patient characteristics placed. A felt-tip pen is then used to clearly draw the
two indicator lines before testing begins.
Months
After an 8- to 12-hour overnight dwell, the dwelled
Patient Age Sex on PD Cause of ESRD
dialysate is completely drained into the empty bag.
1 50 F 54 Chronic glomerulonephritis Immediately after the patient infuses 2˚L of dialy-
2 61 M 85 Nephrosclerosis sis solution, 200˚mL is drained back into the bag on
3a 72 M 55 Diabetic nephropathy which the two fluid-level lines were previously
4 66 M 4 Diabetic nephropathy
marked.
5 59 M 59 Diabetic nephropathy
After the bag is inverted three times to mix, the
6 69 M 52 Nephrosclerosis
patient re-infuses about 190˚mL of the dialysate. The
7 48 F 105 Chronic glomerulonephritis
8 35 M 67 Nephrosclerosis remaining 10˚mL, the amount indicated by a guide
9 71 M 46 Diabetic nephropathy mark at corner, is left within the˚bag.
10a 92 M 45 Diabetic nephropathy After a 4-hour dwell, the dialysate is completely
drained into another twin-bag, and the three dialysate
a Home peritoneal equilibration test was performed by a family
samples are brought to our outpatient clinic for fur-
member.
PD˚= peritoneal dialysis; ESRD˚= end-stage renal disease. ther evaluation.
FIGURE 1 Three kinds of visual aids for the home peritoneal equilibration test (home PET). At our outpatient clinic, visual aids that
showed the home PET procedure (a VCR tape, a DVD disc, and a brochure with photographs) were distributed to the patients.
PET at Home 83
A
E
D
B
F
C
G
FIGURE 2 The home peritoneal equilibration test (home PET) procedure. (A) A guide sheet indicates two fluid levels (200 mL and 10
mL). (B) Drawing a 10 mL line by placing the fresh dialysate bag on the guide sheet. (C) Drawing a 200 mL line. (D) Immediately after
the patient infuses fresh dialysate, 200 mL of the solution is drained into the bag on which the two fluid levels were previously marked.
(E) The drained bag is mixed by inverting three times. (F) About 190 mL of dialysate is re-infused, and the remaining 10 mL (the amount
indicated by the guide mark at the corner) is left in the bag (time 0 sample). (G) After a 4-hour dwell, the dialysate is completely drained
into another twin-bag. The three dialysate samples (the overnight sample, the time 0 sample, and the 4-hour dwell sample) are brought
into the outpatient clinic for further evaluation.
84 Hashimoto and Mima
Dialysate samples were evaluated for D/D ratio 87˚mL vs. 328˚± 110˚mL, p˚= 0.088, r˚= 0.307 (NS);
0
of glucose at hour˚4, PET category, and residual vol- Figures˚3 and˚4].
ume. Residual volume (V) was calculated by: V˚=
r r
2000˚∞ [˚C2˚/ (˚C1˚—C˚2)˚], where C1 is the concentra- Discussion and conclusions
tion of creatinine in the overnight drain bag and C2 is We developed a modified PET (home PET) that is
the creatinine concentration in the drain bag at hour˚0. performed at home by the patient or a family member.
For assessment of PET category, we used the stan- Routine PET determinations in individual patients
dardized PET data of Twardowski et al˚(1). may be useful in defining the optimum PD prescrip-
A standard PET was also performed on a differ- tion and in tracking changes in peritoneal function
ent day, and the data were compared with those ob- over time (3). Periodic PET testing might be omitted,
tained from the home˚PET. however, because of the inconvenience to patients in
visiting a hospital, or because of a labor shortage in
Results the medical facility. We saw a clinical necessity for a
In all 10˚cases, the home PET was performed without simpler PET that could be carried out at regular
trouble. No omissions in filling the indicated param- intervals.
eters of the home PET records were observed. Our home PET has proved to be a clinically use-
Excellent correlations were seen (Figure˚3) be- ful alternative to the standard PET, and it saves time
tween the home PET and the standard PET in the val- and labor surrounding PET procedures. In our case
ues of D/D glucose (r˚= 0.872, p˚= 0.0004) and in the studies, the patients performed the home PET with
0
drain volumes (r˚= 0.788, p˚= 0.0048). No statistical accuracy, and the data were quite compatible with
differences were observed in the mean values of D/D those obtained using the standard˚PET.
0
glucose (0.385˚± 0.054 vs. 0.371˚± 0.052, p˚= 0.329) Our results also demonstrated that, by giving pa-
and drain volume (2340˚± 123˚mL vs. 2372˚± 90˚mL, tients detailed instructions and visual aids, sampling
p˚= 0.221) between the two tests (Figure˚4). errors by the patients and the efforts needed by the
The PET categories based on D/D glucose coin- medical staff to teach the PET procedure could be
0
cided in all cases except one (Table˚II). The PET cat- greatly reduced.
egories based on drain volume also coincided in all Because our home PET employs sampling of di-
cases except one (Table˚II). alysate at hour˚0, the results can be directly compared
Large differences were seen in the calculated val- with past cumulative data using the standard PET, an
ues of residual volume between the two tests, and no additional advantage of the home PET over the
correlation was observed in that parameter [291˚± fast˚PET.
FIGURE 3 Correlations between home peritoneal equilibration test (PET) and standard PET (horizontal axis: home PET; vertical axis:
standard PET). Significant correlations were seen in D/D glucose and in drain volume. D/D˚= the ratio of dialysate glucose at 4˚hours
0 0
to dialysate glucose at time˚0; NS˚= nonsignificant.
PET at Home 85
FIGURE 4 Comparisons of mean values of D/D0 glucose, drain volume, and residual volume between home peritoneal equilibration test
(PET) and standard PET. No significant differences were seen in those parameters between the home PET and the standard PET by paired
t-test. Values are expressed as mean˚± standard deviation. D/D˚= the ratio of dialysate glucose at 4˚hours to dialysate glucose at time˚0.
0
TABLE II Comparison of peritoneal equilibration test (PET) categories based on two different parameters
PET categories from D/D glucose PET categories from drain volume
0
Patient Home PET Standard PET Home PET Standard PET
1 LA LA LA LA
2 HA HA HA HA
3a HA HA HA HA
4 HA HA HA HA
5 LA HA LA LA
6 LA LA LA HA
7 HA HA HA HA
8 LA LA LA LA
9 HA HA HA HA
10a LA LA LA LA
a Home peritoneal equilibration test was performed by a family member.
D/D˚= the ratio of dialysate glucose at 4˚hours to dialysate glucose at time˚0; LA˚= low-average peritoneal transport; HA˚= high-average
0
peritoneal transport.
To pursue patient convenience by reducing hos- We could observe no correlation in the calculated
pital visits, we employed D/D glucose and drain vol- values of residual volume between the two tests. That
0
ume at hour˚4 as parameters for determining PET lack of correlation probably reflects differences in
categories. drain position between home and hospital.
Though we sometimes encountered incompatibil- Because our home PET requires intelligence
ity in PET categories between D/D glucose and di- and good eyesight, applying our methods to all PD
0
alysate-to-plasma (D/P) creatinine (in such cases, the patients would be difficult unless a family mem-
latter data are given priority), it was assumed that re- ber cooperated. However, our home PET might be
peating the tests would clarify the membrane charac- convenient for patients without those problems.
teristics with more accuracy. That is to say, tracking Our method is of particular benefit to patients
the changes in D/D glucose over time might yield whose home PET data closely resemble data ob-
0
very valuable clinical information concerning the in- tained by standard PET. Therefore, a reasonable
dividual peritoneal membrane. method might be to compare the results of two tests
86 Hashimoto and Mima
at the start, and then to select cases for the 7:95—108.
home˚PET. 2 Twardowski ZJ, Nolph KDA, Khanna R, et al. Peri-
We conclude that home PET is a clinically useful toneal equilibration test. Perit Dial Bull 1987;
alternative to the standard PET, saving time and labor 7:138—47.
3 Verger C, Larpent T, Dumontet M. Prognostic value
while maintaining accuracy.
of peritoneal equilibration curves in CAPD patients.
In: Maher JF, Winchester JF, eds. Frontiers in Perito-
Acknowledgment
neal Dialysis. New York: Field, Rich and Associates;
The authors thank Pamela Jewell (Shizuoka City In-
1986: 88—93.
tercultural Affairs Office) for assistance in the prepa-
4 Twardowski ZJ. The fast peritoneal equilibration test.
ration of this manuscript. Semin Dial 1990; 3:141.
References Corresponding author:
1 Twardowski ZJ. Clinical value of standardized equili- Yasuki Hashimoto, MD, Nephrology, Shizuoka City Hospi-
bration tests in CAPD patients. Blood Purif 1989; tal, Ohte-machi, Shizuoka 420-8630 Japan.
Advances in Peritoneal Dialysis, Vol. 18, 2002
Streaming, Mixing, and
Recirculation: Role of the
Peritoneal Access in Continuous
Flow Peritoneal Dialysis
(Clinical Considerations)
Jose A. Diaz—Buxo
Continuous flow peritoneal dialysis (CFPD) is a very most investigators when using double-lumen catheters
promising modality of PD in terms of high rates of of various designs (6,8). The disparity in the results
solute removal and ultrafiltration (UF). The published strongly suggests streaming of the fluid and recircula-
clinical data are characterized by marked variability tion when double-lumen catheters are used, leading to
in terms of clearances and UF. Analysis of those data poor mixing of the fluid and inability to create consis-
suggest significant streaming and recirculation with tent osmotic and solute concentration gradients.
the available double-lumen catheters.
A new double lumen catheter is described. It has Discussion
wide separation between the limbs to minimize stream-
ing and recirculation, and a novel geometric configu- The CFPD concept
ration to maximize internal cross-sectional luminal The terminology applied by various authors to describe
area with the lowest external diameter. CFPD is confusing. Terms include recirculation PD,
Preliminary in vitro studies have shown flow rates continuous flow PD, flow-through PD, and hybrid PD,
consistent with those required for CFPD, satisfactory among others. The modality deserves a better
mixing of the fluid, and minimal streaming and recir- definition.
culation. Clinical validation with long-term studies Continuous flow PD uses the continuous flow tech-
are needed to assess the viability of CFPD as a chronic nique, meaning that a constant flow of fluid is continu-
renal replacement therapy. ously maintained through the peritoneal cavity by
means of two catheters or a double-lumen catheter.
Key words Because CFPD is usually applied as a high-flow sys-
Continuous flow peritoneal dialysis (CFPD), perito- tem (with peritoneal fluid flow rates, Q , in the range
P
neal access, peritoneal catheters, double-lumen cath- of 100˚— 300˚mL/min), it requires lagre volumes of di-
eters, kinetics alysate, for which various sources have been proposed
(9). Those sources include preparation of new dialy-
Introduction sate and regeneration of dialysate by means of sorbents
Continuous flow peritoneal dialysis (CFPD) is perhaps or hemodialysis technology. Regardless of the source
the most promising modality of PD ever, because of of the dialysate, a continuous flow of fresh or regener-
its potential for high clearances and ultrafiltration (UF) ated dialysis solution is provided, obviating the need
(1). However, the published clinical data have been for new terminology. The proper terminology should
remarkably variable in terms of solute clearance (K) be CFPD with regeneration of dialysate using hemodi-
and ultrafiltration rate (UFR) (2—6). The theoretical alysis technology, CFPD with on-line production of
constructs (1,7) predict K, mass transfer coefficients dialysate, CFPD with regeneration of dialysate by sor-
(MTCs), and UFR consistent with the clinical results bent adsorption, CFPD using batch dialysate, and so˚on.
obtained when two separate catheters are used (2,5),
but the constructs overestimate the results obtained by Clinical experiences with various peritoneal access
devices
From: Fresenius Medical Care North America, Lexington, Figure˚1 plots clearances and MTC for CFPD from
Urea
Maryland, U.S.A. various studies using two catheters (2,3,5). The data
88 Diaz—Buxo
are markedly dispersed; however, K is significantly into the circulation. If the incoming solution is being
Urea
higher at the same Q than that observed by investi- bypassed into the outflow lumen, the osmotic gradi-
P
gators using either double-lumen catheters or a single- ent diminishes, and UF drops.
needle device (4,6,8) (both represented by the open
square). The discrepancy can easily be explained by Peritoneal access for CFPD
streaming of the fluid from the inflow limb of the cath- Peritoneal access for CFPD can be classified into two
eter to the outflow limb. The result is high recircula- major categories: two separate catheters and double-
tion and poor mixing of the solution. lumen catheters. The simplest design of the double-
Cruz et al (5) achieved consistent MTC of ap- lumen catheter is a double D configuration, which
Urea
proximately 40˚mL/min using two separate catheters consists of a short tube used for inflow, and a long
and performing 4-hour observations under rigorous tube for outflow (10,11). That basic design has been
conditions. Their results are consistent with the ki- modified by the addition of discs along the tubes in
netic model˚(7). an attempt to diffuse the inflow stream of dialysate
The same investigators observed a UFR very close and to improve mixing˚(6).
to that predicted by the model. Because CFPD uses a The latest modifications of the double-lumen cath-
very high Q , the glucose concentration of the solu- eter may be more significant. Ronco et al have de-
P
tion is maintained relatively constant throughout the signed a double-lumen catheter with a proximal inflow
treatment. Therefore, the expected UF should be close diffuser (similar to a flexible shower head that dif-
to the instantaneous UF (or UF at time˚0). The instan- fuses fluid in a 180-degree pattern) that is positioned
taneous UF for a 1.5% glucose solution is approxi- close to the entry point of the catheter into the perito-
mately 7˚mL/min, a value very close to that observed neum (12). A long, curled tube, similar to a conven-
in two special studies of UF in Cruz et al series˚(5). tional coiled catheter, is used for drainage. The
In contrast, the UFR observed by other investiga- considerable distance between the two lumina and the
tors using double-lumen catheters was very low or diffusing effect of the multiple holes in the inflow sec-
nonexistent (6,8). Once again, streaming of dialysate tion may reduce streaming.
along the catheter can account for the differences. In collaboration with Medigroup Inc. (Naperville,
Glucose is continuously absorbed from the peritoneum IL, U.S.A.), we have developed a double-lumen cath-
FIGURE 1 Effect of peritoneal access on clearance (KUrea) and mass transfer coefficient (MTCUrea) of urea.
Role of Access in CFPD 89
eter with maximum internal separation of the two cross-sectional configuration whereby one tube,
tubes. The catheter can be implanted peritone- slightly oval-shaped, nests within the other crescent-
oscopically or laparoscopically. The new catheter con- shaped tube (Figure˚2). That geometric arrangement
sists of two distinct lumina (tubes) using a novel allows maximum internal diameters (cross sections)
and a minimal external diameter. This unique design
permits passive flow rates well within the required
CFPD parameters (Figure˚3). In˚vitro studies indicate
inflow and outflow rates to be within acceptable
margins.
The tubes are bonded where they pass through the
abdominal wall and subcutaneous tissue. Externally,
they are separate for convenience and ease of use. In-
ternally, they are also separate, each tube terminating
with an appropriately sized fluted section (Figure˚4).
The internal tubes form a double J configuration
which fits near the parietal peritoneum. The double
J shape causes the cranial and caudal limbs to sepa-
rate by 180˚degrees. The configuration, combined with
a functional separation of flutes, means that the mini-
mal separation is at least 13˚cm (approximately
5.25˚in.), and the probable functional separation is
FIGURE 2 Fluted double-lumen catheter with novel configuration.
(Courtesy of Medigroup, Inc., Naperville, IL, U.S.A.) approximately 20˚cm (8.0˚in).
FIGURE 3 Flow comparison of Tenckhoff and fluted double-lumen catheter. Each lumen was tested separately at different head heights.
A 500-mL volume was timed, and the flow rate was calculated. Water was the medium.
90 Diaz—Buxo
systemaccessis the one that causes the most
problems.
References
1 Diaz—Buxo JA. Continuous flow peritoneal dialysis:
clinical applications. Blood Purif 2002; 20:36—9.
2 Shinaberger JH, Shear L, Barry KG. Increasing
efficiency of peritoneal dialysis. Experience with
peritoneal—extracorporeal recirculation dialysis.
Trans Am Soc Artif Intern Organs 1965; 11:76—82.
3 Kraus MA, Shasha SM, Nemas M, Better OS. Ultra-
filtration peritoneal dialysis and recirculating perito-
neal dialysis with a portable kidney. Dial Transplant
1983; 12:385—8.
4 Raj DS, Self M, Work J. Hybrid dialysis: recircula-
tion peritoneal dialysis revisited. Am˚J Kidney Dis
2000; 36:58—67.
5 Cruz C, Melendez A, Gotch FA, Folden T, Crawford
T, Diaz—Buxo JA. Single-pass continuous flow peri-
toneal dialysis using two catheters. Semin Dial 2001;
14:391—4.
FIGURE 4 Detail of fluted terminal portion of each catheter limb. 6 Passlick—Deetjen J, Quellhorst E. Continuous flow
peritoneal dialysis (CFPD): a glimpse into the future.
Preliminary in vitro studies using only passive Nephrol Dial Transplant 2001; 16:2296—9.
hydrostatic pressure have shown good flow rates and 7 Gotch FA. Kinetic modeling of continuous flow
seem to indicate good mixing with minimal stream- peritoneal dialysis. Semin Dial 2001; 14:378—83.
ing and recirculation. While the studies are not con- 8 Mineshima M, Suzuki S, Sato Y, et al. Solute re-
moval characteristics of continuous recirculating
clusive, they do indicate that the basic design should
peritoneal dialysis in experimental and clinical stud-
work. Additional work with urea dilution tests and in
ies. ASAIO˚J 2000; 46:95—8.
vitro radiographic studies are needed to confirm the
9 Diaz—Buxo JA. Evolution of continuous flow perito-
initial reports. Ultimately, controlled, real-life clini-
neal dialysis and the current state of the art. Semin
cal studies will be required to assess the function of
Dial 2001; 14:373—7.
the catheters. 10 Mineshima M, Watanuki M, Yamagata K, et al.
Development of continuous recirculating peritoneal
Conclusion dialysis using a double lumen catheter. ASAIO˚J
The next stage in the evaluation of CFPD as a viable 1992; 38:M377—81.
modality of renal replacement therapy is the demon- 11 Diaz—Buxo JA. Renal care 2000Peritoneal dialy-
stration of consistent MTCs in the predicted range of sis. Prospects for PD in the future. Nephrol News
Issues 1999; 3:12—16.
35˚— 45˚mL/min and a predictable UFR. Such data will
12 Ronco C, Gloukhoff A, DellAquila R, Levin NW.
provide the foundation needed to develop prescrip-
Catheter design for continuous flow peritoneal dialy-
tions and algorithms for the proper monitoring and
sis. Blood Purif 2002; 20:40—4.
management of UF. Following the initial validation
process, the next requirement will be to treat patients
Corresponding author:
for prolonged periods of time to assess acceptance and Jose A. Diaz—BuxoM, D, FACP, Fresenius Medical Care North
safety of the procedure. As in the case of hemodialy- America, 1051˚East Morehead Street, Suite 250, Charlotte,
sis, the simplest and least expensive component of the North Carolina 28204 U.S.A.