---

🫁 Peritoneal Dialysis (PD) - Complete Clinical Reference

---

1. PD APPARATUS - OVERVIEW

Key Components of the PD System:

---

2. PD SOLUTIONS (DIALYSATE)

Composition of PD Fluid:

• Electrolytes - sodium, calcium, magnesium, chloride
• Buffer - lactate (standard) or bicarbonate (biocompatible)
• Osmotic agent - to drive ultrafiltration
• Water as carrier

Osmotic Agents Compared:

Key Physiology:

• At dwell time 0: glucose concentration is highest → maximum osmotic pressure → highest ultrafiltration rate
• Over time, ~2/3 of glucose is absorbed within 4 hours → osmotic gradient falls → UF diminishes
• Icodextrin (a glucose polymer) is NOT absorbed via aquaporins → maintains colloid osmotic pressure for long dwells
• 50% of transcapillary UF occurs through aquaporin-1 (AQP-1) ultra-small pores

Solution Types by pH/Buffer:

Long-term exposure to lactate-acid solution and high glucose damages the peritoneal membrane, leading to loss of mesothelial microvilli, reduced anionic charges, and eventually encapsulating peritoneal sclerosis (EPS).

---

3. PD MODALITIES

---

4. TRANSFER SET & CONNECTOLOGY

The Y-Set System ("Flush-Before-Fill" Technique):

Fresh dialysate bag
        |
        Y-connector
       / \
Drain bag   PD Catheter (patient)

1. Connect Y-set to PD catheter
2. Drain spent dialysate from peritoneum into drain bag first
3. Flush - briefly run fresh dialysate through the Y-set into the drain bag (flushes any touch contaminants out)
4. Fill - infuse fresh dialysate into peritoneum
5. Disconnect; cap catheter

The "flush-before-fill" design dramatically reduced coagulase-negative Staphylococcus (CoNS) peritonitis by flushing away organisms that may have entered during connection.

Connectology Principles:

• Spike connector or Luer-lock system used depending on manufacturer (Baxter, Fresenius)
• Sterile technique at all connection/disconnection steps is mandatory
• Titanium adapter or transfer set adapter connects catheter to exchange tubing
• Transfer sets are changed every 6 months (or per manufacturer protocol)
• All connections must use aseptic technique: mask worn by patient and assistant
• Clamps must be closed before disconnecting any part of the circuit
• Inspect bags for cloudiness, leaks, or particulate matter before each use

CAPD vs APD Connectology:

---

5. PERITONEAL DIALYSIS ACCESS - THE CATHETER

Types of PD Catheters:

Most Widely Used: Double-cuff, Swan-neck, Coiled Tenckhoff Catheter

• Coiled tip → less pain on infusion, less catheter migration, fewer outflow problems
• Swan-neck → downward-pointing exit site → prevents cuff extrusion, reduces infection
• Double cuffs → inner cuff in rectus muscle (prevents leaks); outer cuff in subcutaneous tissue (blocks external bacterial migration)

Catheter Placement Techniques:

Peritoneoscopic placement has been shown to have longer catheter survival compared to blind technique.

Cuff Placement:

• Inner (deep) cuff → placed within the rectus abdominis muscle (prevents leaks and peritoneal fluid tracking)
• Outer (superficial) cuff → placed in subcutaneous tissue, 2-4 cm from skin exit site → dead space between cuffs blocks bacteria tracking inward
• Ingrowth of fibrous tissue into both cuffs provides secure fixation and allows water immersion (bathing/swimming)

Exit Site Positioning:

• Exit site should face downward and laterally
• Determined with patient in upright position before insertion
• Avoid: beltline, prior surgical scars, abdominal midline
• Special situations: presternal exit site - used in obese patients, patients with ostomies, or incontinent children - shown to decrease peritonitis and exit-site infection, with catheter survival up to 95% at 2 years

---

6. CATHETER CARE - POST-INSERTION

Immediate Post-Operative Care:

• Cover with non-occlusive dressing
• Catheter should NOT be used for 10-14 days post-placement
• Flush catheter with saline or dialysate 2-3 times/week until PD starts
• PD typically started 2-4 weeks after placement (allows wound healing + cuff ingrowth)
• Urgent-start PD (within 24 hours) may be attempted with low-volume exchanges if no other access is available

Ongoing Catheter Care:

• Immobilize the catheter with tape or catheter securement device to prevent traction on exit site
• Never pull or tug on the catheter
• Inspect for signs of infection at every encounter
• Prophylactic antibiotics at time of catheter insertion (first-generation cephalosporin or glycopeptide based on local microbiology)

---

7. EXIT SITE CARE

Definition of Exit Site:

Routine Exit Site Care Protocol:

1. Wash hands thoroughly before touching the catheter
2. Clean exit site daily with antiseptic solution (chlorhexidine or normal saline per center protocol)
3. Apply topical antibiotic daily:
   • Mupirocin (Bactroban) cream/ointment - reduces Staphylococcus aureus exit-site infections
   • Gentamicin cream - alternative; also covers gram-negative organisms (especially Pseudomonas)
4. Apply sterile dressing and secure catheter
5. Avoid submersion in non-chlorinated water (lakes, ponds, baths) - showers preferred

Exit Site Infection (ESI) - Recognition:

Exit Site Infection - Common Organisms:

• Staphylococcus aureus - most common
• Pseudomonas aeruginosa - associated with higher risk of catheter loss
• Coagulase-negative Staphylococci
• Gram-negative rods

Tunnel Infection:

• Infection tracking along the subcutaneous catheter tunnel
• Presents as pain/tenderness/redness along the tunnel tract
• Diagnosed by ultrasound (shows fluid/edema around catheter)
• If tunnel infection reaches inner cuff → catheter removal often required
• Tunnel + exit site infection → treat aggressively with systemic antibiotics; catheter removal if no improvement in 2-3 weeks

Prevention of Exit Site Infection:

---

8. PERITONITIS - OVERVIEW (Linked to Access/Exit Site Care)

Routes of Entry:

1. Intraluminal - touch contamination during exchange (most common)
2. Periluminal - bacteria tracking along outside of catheter from exit site
3. Transmural - bowel flora translocating across intestinal wall
4. Hematogenous - transient bacteremia seeds peritoneum
5. Transvaginal - organisms via female reproductive tract
6. Fungal - in immunocompromised or post-antibiotic patients

Diagnosis (2 of 3 criteria required):

• Organisms on Gram stain/culture of effluent
• Cloudy fluid (WBC >100/mm³, >50% neutrophils)
• Clinical signs of peritoneal inflammation + cloudy fluid + abdominal pain

Impact of Y-Set on Peritonitis:

The introduction of the Y-set and flush-before-fill technique led to a dramatic decrease in CoNS peritonitis rates globally - one of the most significant improvements in PD management.

---

9. COMPLICATIONS OF CATHETER/ACCESS

---

10. SUMMARY TABLE - PD SYSTEM AT A GLANCE

---

---

Peritoneal Dialysis Therapies - Intermittent & Continuous: Complete Reference

---

1. THE THREE FUNDAMENTAL STEPS OF EVERY PD EXCHANGE

FILL → DWELL → DRAIN

The entire exchange (instillation + drainage) should not exceed 30 minutes in a functioning catheter.

---

2. CLASSIFICATION OF PD MODALITIES

PD THERAPIES
│
├── CONTINUOUS (peritoneum always filled with dialysate)
│       ├── CAPD  – Continuous Ambulatory PD (manual)
│       ├── CCPD  – Continuous Cycling PD (APD + daytime dwell)
│       └── CFPD  – Continuous Flow PD (experimental)
│
└── INTERMITTENT (peritoneum has dry/empty periods)
        ├── IPD   – Intermittent PD (classic/acute)
        ├── NIPD  – Nightly Intermittent PD (APD, dry day)
        └── TPD   – Tidal PD (partial drain variant)

---

3. CONTINUOUS THERAPIES

A. CAPD - Continuous Ambulatory Peritoneal Dialysis

Morning (6 AM)    → Drain overnight dwell + Fill fresh bag [Exchange 1]
Midday (12 PM)    → Drain + Fill                           [Exchange 2]
Afternoon (5 PM)  → Drain + Fill                          [Exchange 3]
Bedtime (10 PM)   → Drain + Fill with icodextrin/high glucose [Overnight dwell]
Next morning      → Drain overnight + repeat cycle

• No machine - portable, travel-friendly
• Lower cost - important in low/middle-income countries
• Better for patients uncomfortable sleeping connected to a machine
• Easier for "fussy" catheters (can control drain speed)
• Preferred in cirrhosis/ascites (can control drain volume precisely)
• More confident with twin-bag technique training
• Better suited for low transporters (long dwell time maximizes diffusion)

• Multiple sterile connections per day = higher peritonitis risk vs APD
• Disruptive to daytime activities
• Higher risk of hernias, leaks, and back pain (constant intra-abdominal pressure day and night)
• Challenging beyond 4 exchanges/day - those patients better switched to APD
• Less flexible for working patients

---

B. CCPD - Continuous Cycling Peritoneal Dialysis

10 PM  → Connect to cycler; cycler runs 3-5 automated exchanges overnight
6 AM   → Cycler delivers final "last fill" (2 L icodextrin)
6 AM   → Disconnect from machine; patient is FREE during day
10 PM  → Drain last fill + reconnect cycler → repeat

• Single daily connection = fewer sterile breaks = lower peritonitis risk
• Daytime freedom (ideal for working patients, children in school)
• Lower risk of hernias and leaks if daytime is "dry" (no abdominal pressure during day)
• Lower risk of back pain
• Better for urgent-start PD (supine, low-volume cycling)
• Easier for assisted PD in elderly (carer connects once at night)
• Remote monitoring via cycler data transmission
• Cycler warms fluid before infusion (reduces shivering/discomfort)
• Better suited for high transporters (rapid short dwells maximize UF before glucose is absorbed)

• Higher cost ($$$$) - cycler, cartridges, specialized tubing
• Requires electricity and space
• Cycler alarms can disturb sleep
• Drain pain and low-drain alarms more common
• Less confident with twin-bag manual backup technique
• Challenging in cirrhosis/ascites management

---

4. INTERMITTENT THERAPIES

A. IPD - Intermittent Peritoneal Dialysis

• Peritoneum rests between sessions → reduced membrane exposure to glucose
• Lower intraperitoneal pressure most of the time → fewer hernias and leaks
• Feasible in acute kidney injury without formal catheter maturation
• Nurse-managed in hospital; no patient self-care required

• Least efficient of all PD modalities for solute clearance
• Requires frequent hospital attendance
• Short dwells may not achieve adequate equilibration with large solutes
• Not suitable as a long-term ESKD modality
• Cardiovascular instability can still occur with rapid fluid shifts

---

B. NIPD - Nightly Intermittent Peritoneal Dialysis

• Maximum daytime freedom with empty abdomen
• Lowest intraperitoneal pressure of any PD modality
• Lowest risk of hernias, leaks, and back pain
• Less glucose absorption (fewer hours of contact)
• Less peritoneal membrane exposure to glucose/lactate
• Reduced risk of hernia formation

• Insufficient for anuric patients - relies on RKF for additional clearance
• Lowest solute and fluid removal of all continuous/APD options
• As RKF declines, must transition to CCPD or add daytime dwell
• Short dwell times limit large-solute and middle-molecule removal

---

C. TPD - Tidal Peritoneal Dialysis

Fill: 2.0 L
Dwell: short
Drain: only 1.4 L drained (70%)
Retained: 0.6 L stays in peritoneum
Next fill: 1.4 L added (total 2.0 L again)
→ Repeat cycles → Full drain at end

• Originally designed to enhance diffusive clearance (results were disappointing - not used for this)
• Current main use: Management of low-drain alarms on the cycler
• Also used for patients with pain during inflow or drain phases
• Maintains continuous membrane contact → no "dead time" during refilling

• Does NOT significantly improve solute clearance over standard APD
• More complex prescription
• Higher dialysate volume usage = higher cost

---

5. INCREMENTAL PD - A MODERN APPROACH

Typical Incremental PD Prescriptions:

• Reduces early workload - builds patient confidence gradually
• Lower cost (less dialysate)
• Less glucose exposure - protects peritoneal membrane
• Fewer mechanical complications early on
• May slow decline of RKF
• Personalized to patient lifestyle

From the CANUSA cohort: every 5 L/week/1.73m² of residual creatinine clearance = 12% lower relative risk of death. RKF provides middle-molecule removal, volume control, and metabolic benefits that peritoneal clearance alone cannot fully replace.

---

6. URGENT-START PD

---

7. PERITONEAL MEMBRANE TRANSPORT - MATCHING MODALITY TO PATIENT

The Peritoneal Equilibration Test (PET)

Important caveat (modern practice): While transport type theoretically guides modality choice, current guidelines recommend prescriptions be individualized to patient lifestyle and priorities, not solely dictated by transport kinetics. For example, a high transporter who works nights may still prefer CAPD.

---

8. PRESCRIPTION VARIABLES - WHAT TO SPECIFY FOR EVERY PD ORDER

• 1.5% - minimal UF; euvolaemic patients
• 2.5% - moderate UF; mild volume overload
• 4.25% - maximum UF; significant volume overload; highest glucose load

---

9. DIALYSIS ADEQUACY - TARGET MEASURES

Modern ISPD approach: "Adequacy" is now framed as goal-directed dialysis - shared decision making between patient and care team focusing on quality of life, symptom control, and individualized targets, not just Kt/V numbers alone.

---

10. COMPARISON TABLE: ALL PD MODALITIES AT A GLANCE

---

11. KEY CLINICAL DECISION POINTS

Patient starting PD
│
├── Has significant RKF?
│       YES → Consider NIPD or incremental PD
│       NO  → CCPD or full-dose CAPD
│
├── Works during the day?
│       YES → CCPD (daytime freedom)
│       NO  → CAPD or CCPD both acceptable
│
├── High peritoneal transporter?
│       YES → APD/CCPD (short dwells before glucose absorbed)
│       NO  → CAPD (long dwells for maximal diffusion)
│
├── Recent catheter placement (<2 weeks) or hernia risk?
│       YES → Urgent-start APD supine; low volumes; dry day
│
├── Low drain alarms / infusion pain on APD?
│       YES → Tidal PD (TPD) - retain 30% reserve volume
│
└── AKI / hospital setting?
        → IPD or low-volume APD

---

---

CAPD - Apparatus, Procedure, Pros & Cons

---

1. CAPD APPARATUS - COMPLETE EQUIPMENT LIST

The Peritoneal Membrane (the "natural dialyzer")

---

The PD Catheter

---

Full CAPD System Components:

---

2. CAPD SYSTEM DIAGRAM

---

3. CAPD PROCEDURE - STEP BY STEP

Pre-Exchange Preparation

1. Wash hands thoroughly with soap and water for at least 2 minutes
2. Dry with clean towel; apply alcohol-based hand rub
3. Put on surgical face mask (patient and any helper)
4. Gather all equipment: new dialysate bag, drain bag, Y-set, antiseptic supplies
5. Inspect the dialysate bag:
   • Check expiry date
   • Check for cloudiness or particulates (discard if present)
   • Check bag for leaks or damage
   • Warm to body temperature (37°C) using warming pad
6. Set up the Y-set: connect fresh bag and drain bag to the two limbs of the Y-connector (if not pre-attached)

---

The Exchange Procedure (Flush-Before-Fill - Double Bag System)

STEP 1 - CONNECT
Patient connects Y-set to transfer set adapter
(mask on; strict aseptic technique; all clamps closed)

STEP 2 - FLUSH (5 seconds)
Open fresh dialysate bag → flush briefly into drain bag
(purges any touch contaminants from connection point
into drain bag - this is the "flush before fill" safety step)

STEP 3 - DRAIN (20 minutes)
Open clamp to drain bag → spent dialysate drains from
peritoneum by gravity into drain bag
(first 1.6-1.8L drains fast; slows as residual volume
falls below 300 mL)
Clamp drain limb when drainage complete

STEP 4 - FILL (10 minutes)
Open clamp to fresh dialysate bag →
2L of warm fresh dialysate flows by gravity into
peritoneal cavity
Clamp when bag is empty

STEP 5 - DISCONNECT
Disconnect Y-set; apply sterile cap to transfer set
Secure catheter against body with tape/binder

STEP 6 - DWELL (4-8 hours)
Patient is FREE to move, walk, work
Diffusion + ultrafiltration occur continuously

---

CAPD Daily Schedule (Typical 4-Exchange Regimen):

Most common CAPD prescription (PDOPPS registry): 4 exchanges/day × 2.0-2.5 L/exchange

---

The Double-Bag System in Detail:

         [FRESH DIALYSATE BAG]
                 |
         --------Y--------
        |                 |
  [Drain bag]      [Transfer set → Catheter → Peritoneum]

Step 1: Short flush → fresh dialysate runs briefly → drain bag
        (clears intraluminal contaminants)

Step 2: Drain spent dialysate → drain bag (20 min gravity)

Step 3: Break "frangible pin" in tubing → fill peritoneum (10 min gravity)

Step 4: Clamp, disconnect, cap → dwell begins

The frangible (breakable) pin is a built-in safety feature in the tubing. Breaking it opens the fill channel after drainage is complete, ensuring the correct sequence is always followed.

---

4. PROS AND CONS OF CAPD

✅ ADVANTAGES (PROS)

Clinical Advantages:

Practical / Lifestyle Advantages:

---

❌ DISADVANTAGES (CONS)

Clinical Disadvantages:

Practical Disadvantages:

---

5. INDICATIONS FOR CAPD

Renal Indications:

• Inability to perform hemodialysis
• Vascular access failure
• HD intolerance
• Children age 0-5 years
• Severe peripheral vascular disease
• Severe cardiac function impairment
• Patient preference

• Bleeding diathesis (no heparin needed in CAPD)
• Multiple myeloma
• Needle anxiety
• Labile diabetes mellitus
• Lifestyle preference

Non-Renal Indications:

• Drug poisoning
• Refractory congestive heart failure
• Hepatic failure
• Hypo/hyperthermia
• Dialysis-associated ascites
• Pancreatitis

---

6. CONTRAINDICATIONS

---

7. CAPD vs APD - QUICK REFERENCE

---

---

APD & IPD - Apparatus, Procedure & System Details

---

PART A: APD - AUTOMATED PERITONEAL DIALYSIS

---

1. APD APPARATUS - COMPLETE EQUIPMENT

The Cycler Machine - Core Component

Commercial Cycler Examples:

---

Full APD Equipment List:

---

APD vs CAPD - Equipment Differences:

---

2. APD PROCEDURE - STEP BY STEP

Pre-Session Setup (Evening - ~30 mins before sleep)

• Cycler machine (already at bedside)
• New disposable cassette/tubing set (changed every session or per manufacturer)
• Required number of dialysate supply bags for the night
• Patient mask, alcohol wipes, sterile cap

• Insert new disposable cassette into cycler housing
• Connect supply bags to the appropriate supply ports on the cassette
• Connect drain tubing to drain point (household drain, toilet, or large drain bag)
• Prime the tubing (cycler auto-primes on most modern machines)

• Total therapy time (e.g., 8-9 hours)
• Fill volume per cycle (e.g., 2.0-2.5 L)
• Number of cycles (e.g., 4-5 overnight cycles)
• Dwell time per cycle (calculated automatically)
• Last fill volume and solution type (e.g., 2L icodextrin for daytime dwell)

• Cycler heats dialysate automatically to 37°C before each fill

---

The Nightly APD Session (CCPD Mode):

10:00 PM  Patient connects to cycler
          ↓
          INITIAL DRAIN
          Drains any residual fluid from last daytime dwell

          ↓ CYCLE 1
          FILL (10-15 min) → Cycler pumps 2L warm fresh dialysate
          DWELL (1-2 hrs)  → Diffusion + UF occur
          DRAIN (20-30 min)→ Cycler drains spent dialysate to drain

          ↓ CYCLE 2 → same sequence

          ↓ CYCLE 3 → same sequence

          ↓ CYCLE 4 → same sequence

          ↓ CYCLE 5 (if programmed)

          ↓ LAST FILL (6 AM)
          Cycler delivers final 2L icodextrin or glucose bag
          → This stays in peritoneum all day (daytime dwell)

6:00 AM   DISCONNECT from cycler
          Apply sterile cap to transfer set
          Patient FREE all day

10:00 PM  Reconnect → drain last fill → new session begins

---

Tidal APD Mode (for drain alarms or infusion pain):

Standard: Fill 2L → Drain ALL → next fill 2L
                  ↓
70% Tidal:  Fill 2L → Drain only 1.4L (70%)
             → 0.6L stays as "tidal reserve"
             → Next fill: only 1.4L added (total back to 2L)
             → Repeat until final complete drain

Tidal mode prevents the cycler from alarming when the peritoneum empties and also reduces end-drain pain from catheter tip touching pelvic structures.

---

Disconnecting in the Morning:

1. Allow cycler to complete last fill delivery
2. Stop cycler; clamp patient line
3. Put on mask
4. Disconnect patient line from transfer set using aseptic technique
5. Apply sterile cap to transfer set
6. Secure catheter against body
7. Log therapy data or review cycler screen for overnight summary (total UF, total drained, any alarms)

---

3. APD - KEY CLINICAL FEATURES

---

4. APD PROS & CONS

✅ APD Advantages:

❌ APD Disadvantages:

---

---

PART B: IPD - INTERMITTENT PERITONEAL DIALYSIS

---

5. IPD APPARATUS

IPD is the simplest PD setup - primarily a gravity-based system:

IPD may also use an APD cycler in hospital settings when available - the cycler is simply programmed for short, rapid cycles without a daytime last fill.

---

6. IPD PROCEDURE - STEP BY STEP

Session Setup:

1. Warm dialysate bags to 37°C
2. Prepare enough bags for entire session (10-24 exchanges × 1-2L = 20-40L total)
3. Prime tubing; connect to PD catheter using aseptic technique
4. Position patient: supine (hospital bed)

Each Exchange (repeated 10-24 times per session):

FILL (5-10 min)
  Open fill clamp → gravity infills 1-2L warm dialysate
  Close fill clamp when bag empty

DWELL (30-60 min)
  Both clamps closed
  Diffusion + UF occur across peritoneal membrane
  Nurse documents time started

DRAIN (15-20 min)
  Open drain clamp → spent dialysate drains by gravity into drain bag
  Close drain clamp when drainage stops (or slows to a trickle)
  Record drain volume and appearance (clear vs cloudy)

REPEAT → hang new dialysate bag → next exchange

Full IPD Session:

---

7. IPD - SPECIAL CONSIDERATIONS

Acute IPD (for AKI):

• Used when urgent renal replacement is needed but HD is unavailable
• Effective for hyperkalaemia and acidosis correction
• Short dwells + high glucose concentration (2.5%-4.25%) for maximum UF
• Used in low-resource settings and during equipment shortages (e.g., COVID-19)
• Catheter may be temporary (acute) or permanent Tenckhoff placed urgently

IPD with APD Cycler (hospital):

• Cycler programmed for: 1-2L fill × 10-20 rapid cycles × 30-60 min dwell
• No last fill at end
• Drain to bedside bag or hospital drain
• More precise volume control and less nursing burden than gravity IPD

---

8. IPD PROS & CONS

✅ IPD Advantages:

❌ IPD Disadvantages:

---

9. SIDE-BY-SIDE COMPARISON: CAPD vs APD vs IPD

---

10. ALARM MANAGEMENT ON APD CYCLER

---

---

Assessment of Peritoneal Membrane Permeability

---

1. WHY ASSESS THE PERITONEAL MEMBRANE?

• Classify transport status to guide PD prescription
• Detect ultrafiltration failure (UFF) early
• Monitor membrane deterioration from repeated peritonitis or long-term glucose exposure
• Evaluate free water transport via aquaporin-1 channels
• Adjust modality (CAPD vs APD) and dwell time to suit individual membrane biology

---

2. STRUCTURE OF THE PERITONEAL MEMBRANE - TRANSPORT BASIS

Key concept: Glucose has a very low osmotic reflection coefficient through small pores (near 0 = passes freely) but a very HIGH reflection coefficient through aquaporin-1 channels (= 1, completely impermeable). This is why glucose drives UF mainly through AQP-1 - water crosses but glucose cannot → creates an oncotic gradient.

• Peritoneal capillary wall = main barrier
• Interstitium = significant additional barrier to water and solute movement
• Mesothelial cell layer = tertiary barrier

---

3. WHAT IS "TRANSPORT STATUS"?

• Effective peritoneal surface area
• Capillary density and vascularity
• Membrane permeability

---

4. THE PERITONEAL EQUILIBRATION TEST (PET)

The Gold Standard Test for Membrane Permeability

---

PET Procedure - Step by Step:

---

PET Calculations:

---

PET Interpretation Graph:

---

PET Classification Cutoffs (at 4 hours):

~70% of patients have stable transport status at 1 year post-PET; ~50% remain stable at 2 years. Transport can increase (worsen) with repeated peritonitis, long-term PD, or membrane damage.

---

PET Results - Prescription Guidance:

Modern practice caveat: While transport status guides prescription theoretically, current ISPD guidelines recommend prescriptions be individualized to patient lifestyle and preference rather than solely dictated by PET results. Patient preference now takes priority.

---

5. UF CAPACITY ASSESSMENT FROM PET

• Perform a 4-hour dwell with 3.86%/4.25% glucose
• UF < 400 mL with high-concentration solution = confirmed Ultrafiltration Failure (UFF)

---

6. ULTRAFILTRATION FAILURE (UFF) - CLASSIFICATION

---

7. ALTERNATIVE PET TESTS

A. Mini-PET (Fast PET)

B. Double Mini-PET

C. 24-Hour Dialysate Collection

D. MTAC (Mass Transfer Area Coefficient)

• The theoretical instantaneous maximal solute clearance at time 0, without ultrafiltration
• Requires computer modelling of multiple dialysate samples
• Represents true membrane permeability independent of dwell time and UF
• Clinically approximated by: 4-hour D/P ratio or 24-hour clearance
• Used mainly in research; not routine clinical practice

---

8. FACTORS THAT ALTER TRANSPORT STATUS OVER TIME

---

9. WHEN TO PERFORM THE PET - CLINICAL INDICATIONS

Current perspective: PET is NOT required routinely for every PD patient at every center. Modern PD prescription is primarily driven by patient preference and clinical response, not solely by PET transport category. Several expert centers no longer perform routine PET unless clinically indicated.

---

10. SUMMARY TABLE - PET AT A GLANCE

---

---

Acute Peritoneal Dialysis - Definition, Apparatus, Procedure, Pros & Cons

---

1. DEFINITION

Acute PD = a form of Intermittent Peritoneal Dialysis (IPD) performed in a hospital or clinic, using rapid, repeated short-dwell exchanges over sessions of 8-24 hours, repeated several times per week as clinically needed, with dry periods between sessions.

Key Distinctions from Chronic PD:

---

2. INDICATIONS FOR ACUTE PD

Primary Renal Indication: Acute Kidney Injury (AKI)

Non-Renal Indications:

• Refractory congestive heart failure - fluid removal without hemodynamic instability
• Hepatic failure - adjunct to liver support
• Pancreatitis - historically used (controversial; peritoneal lavage principle)
• Hypo/hyperthermia - temperature correction using warm or cool dialysate
• Dialysis-associated ascites

Special Clinical Situations where Acute PD is Preferred:

• Low-resource settings where HD machines are unavailable
• COVID-19 pandemic - used when HD machines were in short supply in developed countries
• Paediatric AKI - well-tolerated in neonates and infants
• Cardiovascular instability - PD causes slower, gentler fluid/solute shifts than HD
• Severe peripheral vascular disease - no vascular access required
• Bleeding diathesis - no heparin required
• Remote/rural hospitals - simple gravity setup requires minimal equipment

---

3. ACUTE PD APPARATUS

---

Equipment List - Acute PD Setup:

---

Acute PD Catheter Types:

Best practice: Even in the acute setting, placing a permanent double-cuff Tenckhoff catheter (surgically or percutaneously under ultrasound/fluoroscopy) is preferred over a rigid acute catheter. Rigid catheters are associated with higher complication rates (bowel perforation, leaks, infection).

---

Acute Catheter Insertion - Methods:

---

4. ACUTE PD PROCEDURE - STEP BY STEP

Phase 1: Pre-Procedure Preparation

1. Obtain consent and explain procedure to patient/family
2. Empty the bladder - catheterise if necessary (prevents bladder injury during trocar insertion)
3. Check bowel - ensure not distended; NG tube if needed
4. Blood tests: FBC, coagulation screen, electrolytes, BUN, creatinine
5. Correct coagulopathy if severe (INR > 2.0 or platelet < 50,000 is relative concern)
6. Mark insertion site: infraumbilical midline (2-3 cm below umbilicus); avoid prior surgical scars
7. Prophylactic antibiotic: single dose 1st or 2nd generation cephalosporin IV before insertion
8. Warm dialysate bags to 37°C

---

Phase 2: Catheter Insertion (Bedside Seldinger/Trocar)

1. Position patient: supine, flat
2. Prep abdomen with antiseptic; sterile drape
3. Local anaesthetic: 1% lidocaine to skin, subcutaneous tissue, fascia
4. Small stab incision at infraumbilical midline
5. Insert trocar needle → confirm peritoneal entry
   (loss of resistance; aspirate for pre-existing fluid/blood/bowel gas)
6. Insert guidewire through needle
7. Remove needle; dilate tract
8. Thread catheter over guidewire/stylet toward pelvis (pouch of Douglas)
9. Remove stylet/guidewire; secure catheter at skin with suture
10. Apply sterile dressing
11. Test function: infuse 500mL warm saline → drain → confirm free flow

---

Phase 3: The Acute PD Exchange Procedure

STEP 1 - FILL (5-10 minutes)
│  Open fill clamp
│  1-2L warm (37°C) dialysate flows by gravity from bag on IV pole
│  into peritoneal cavity
│  Close fill clamp when bag empties

STEP 2 - DWELL (30-60 minutes)
│  All clamps closed
│  Diffusion: urea, creatinine, K⁺, phosphate move blood → dialysate
│  Ultrafiltration: water drawn across by osmotic gradient (glucose)
│  Nurse records start time

STEP 3 - DRAIN (15-20 minutes)
│  Open drain clamp
│  Spent dialysate drains by gravity into drain bag below bed
│  Nurse records drain volume + appearance (clear vs cloudy)
│  Close drain clamp
│  Record net UF = drain volume - fill volume
│  Hang fresh bag → repeat cycle

---

Acute PD Session Parameters:

---

Fluid Balance Monitoring Per Exchange:

Exchange #  | Fill Vol | Drain Vol | Net UF   | Appearance  | Time
------------|----------|-----------|----------|-------------|-------
1           | 1000 mL  | 950 mL    | -50 mL   | Clear       | 06:30
2           | 1000 mL  | 1150 mL   | +150 mL  | Clear       | 07:30
3           | 2000 mL  | 2300 mL   | +300 mL  | Clear       | 08:30
...

RUNNING TOTAL UF = sum of all net UF values

Positive net UF = fluid removed from patient (desired). Negative = fluid absorbed.

---

Heparin Protocol for Cloudy/Fibrinous Effluent:

• Add 500-1000 units heparin per litre of dialysate
• Prevents catheter blocking from fibrin clots
• Does NOT cause systemic anticoagulation (not absorbed from peritoneum)

---

5. ACUTE PD - PROS AND CONS

✅ ADVANTAGES (PROS)

Clinical Advantages:

Logistical/Resource Advantages:

---

❌ DISADVANTAGES (CONS)

Clinical Disadvantages:

---

6. ACUTE PD vs OTHER RRT MODALITIES

---

7. MONITORING DURING ACUTE PD

---

8. COMPLICATIONS OF ACUTE PD

---

9. SUMMARY - ACUTE PD AT A GLANCE

ACUTE PD
│
├── DEFINITION: Temporary RRT using peritoneum during AKI
│
├── CATHETER: Rigid acute / semi-rigid (bedside) OR Tenckhoff (preferred)
│
├── PROCEDURE: Rapid IPD exchanges
│   Fill (1-2L, 10 min) → Dwell (30-60 min) → Drain (20 min)
│   Repeated 10-24×/session over 8-24 hours
│   3-4 sessions/week; DRY between sessions
│
├── BEST FOR:
│   ✓ Haemodynamically unstable AKI
│   ✓ No vascular access
│   ✓ Bleeding risk (no heparin)
│   ✓ Low-resource settings
│   ✓ Paediatric AKI
│   ✓ COVID-19 / resource crisis
│
├── NOT SUITABLE FOR:
│   ✗ Recent abdominal surgery / peritonitis
│   ✗ Severely catabolic patients needing high clearance
│   ✗ Extreme hyperkalaemia needing immediate correction
│   ✗ Respiratory failure worsened by abdominal fill
│
└── KEY ADVANTAGE: No machine, no vascular access, no anticoagulation,
    haemodynamically gentle, works with basic nursing skills

---

Acute Peritoneal Dialysis (Acute PD) - Definition, Apparatus, Procedure, Pros & Cons

---

1. DEFINITION

"PD can be used in patients with AKI to treat hyperkalemia and acidosis in a manner equivalent to that of HD and has been used successfully in low-income countries with limited resources. During the COVID-19 pandemic, many developed countries also used PD when dialysis machines to treat AKI were in short supply." - Fischer's Mastery of Surgery, 8th Edition

---

2. INDICATIONS FOR ACUTE PD

Renal Indications (AKI):

Absolute Renal Indications (where PD is preferred over HD):

Non-Renal Indications:

Special Contexts:

---

3. ACUTE PD APPARATUS

Full Equipment List:

Acute PD Catheter Types:

---

4. ACUTE PD CATHETER INSERTION - TECHNIQUES

A. Blind (Trocar/Seldinger) Technique - Bedside:

• Empty bladder (catheterise if needed)
• Decompress stomach (NG tube if needed)
• Position: supine; identify insertion point (midline, 2-3 cm below umbilicus or left/right paramedian)
• Mark and avoid prior surgical scars

1. Skin prep with chlorhexidine; sterile drapes applied
2. Infiltrate skin, subcutaneous tissue, and rectus sheath with 1-2% lidocaine
3. Small 1 cm skin incision at marked point
4. Insert trocar-cannula perpendicular to skin → advance with controlled pressure until "give" felt as peritoneum entered
5. Remove trocar inner stylet; insert catheter through cannula → direct toward pelvis (pouch of Douglas)
6. Withdraw cannula; secure catheter to skin with suture and sterile dressing
7. Test function: fill 500 mL, drain - confirm free flow

B. Seldinger (Guidewire) Technique - Bedside:

1. Local anaesthesia; 18G needle inserted at same midline point
2. Enter peritoneum; confirm with aspiration of peritoneal fluid
3. Insert guidewire through needle → remove needle
4. Dilate tract over guidewire
5. Advance catheter over guidewire into pelvis
6. Remove guidewire; secure catheter; test fill/drain

C. Surgical / Laparoscopic Placement (planned acute):

• Performed under GA/LA in operating theatre
• Allows direct visualisation, omentum management
• Enables permanent Tenckhoff placement
• Used when urgent-start chronic PD is planned

Low-volume PD may begin within 24 hours of catheter placement if urgent RRT is needed (before normal 2-4 week healing window), using low volumes and supine positioning to minimise leak risk.

---

5. ACUTE PD PROCEDURE - STEP BY STEP

Preparation Before Each Session:

1. Confirm correct dialysate bag (1.5% for maintenance; 2.5-4.25% for fluid removal)
2. Warm all dialysate bags to 37°C (cold dialysate causes discomfort, hypothermia, and vasoconstriction)
3. Add additives if prescribed:
   • Heparin 500 units/L - prevents fibrin clot blockage of catheter
   • KCl - only if patient is hypokalaemic (most AKI patients are hyperkalaemic - no KCl)
   • Insulin - for hyperglycaemic patients using high-glucose dialysate
4. Set up and prime the fill and drain tubing
5. Don mask and gloves; maintain aseptic technique throughout

---

The Exchange Cycle (repeated 10-24 times per session):

┌─────────────────────────────────────────────────────┐
│                  ACUTE PD EXCHANGE CYCLE             │
│                                                     │
│  STEP 1: FILL  (5-10 minutes)                       │
│  Open fill clamp → 1-2L warm dialysate flows        │
│  by gravity into peritoneal cavity                  │
│  Close fill clamp when bag empties                  │
│                    ↓                                │
│  STEP 2: DWELL  (30-60 minutes)                     │
│  Both clamps CLOSED                                 │
│  Diffusion: urea, creatinine, K⁺, toxins move      │
│  from blood → dialysate down concentration gradient │
│  UF: water moves by osmosis into dialysate          │
│  Start timer; document time                         │
│                    ↓                                │
│  STEP 3: DRAIN  (15-20 minutes)                     │
│  Open drain clamp → spent dialysate drains          │
│  by gravity into drain bag below                    │
│  Measure and record drain volume + appearance       │
│  Close drain clamp                                  │
│                    ↓                                │
│  Hang NEW dialysate bag → REPEAT cycle              │
└─────────────────────────────────────────────────────┘

Session Parameters:

---

Fluid Balance Monitoring (Critical in Acute Setting):

---

High-Volume Acute PD:

• Fill volume: 2L per exchange
• Very short dwell: 15-30 minutes
• 24-40 exchanges per 24 hours
• Total volume: up to 40-80 L/day
• Equivalent clearance to continuous renal replacement therapy (CRRT) in some studies

---

6. ACUTE PD - PROS AND CONS

✅ ADVANTAGES (PROS)

Clinical Advantages:

Logistical/Operational Advantages:

---

❌ DISADVANTAGES (CONS)

Clinical Disadvantages:

Procedural / Technical Disadvantages:

---

7. CONTRAINDICATIONS TO ACUTE PD

---

8. ACUTE PD vs OTHER RRT MODALITIES

---

9. SPECIAL CONSIDERATIONS IN ACUTE PD

Additives to Dialysate:

Managing Turbid (Cloudy) Effluent:

• Cloudy effluent = possible peritonitis → sample immediately for cell count, culture, Gram stain
• Diagnosis: WBC >100/mm³ with >50% neutrophils
• Empiric intraperitoneal antibiotics: gram-positive coverage (vancomycin or 1st-gen cephalosporin) + gram-negative coverage (3rd-gen cephalosporin or aminoglycoside)

Urgent Start Protocol (Catheter placed <2 weeks ago):

• Use low volume (500mL-1L) fills
• Patient supine throughout (reduces pressure on exit site)
• APD cycler preferred if available (lower leak risk than manual CAPD in this setting)
• Dry abdomen when patient is upright or mobilising
• Gradually increase fill volume to 2L over 2-4 weeks

---

10. SUMMARY TABLE

---