caths and dialysis continued
Central Venous Catheters: temporary vs permanent
Temporary central venous catheter (Vas cath): used during AKI or when rapid access is needed; can be removed if the patient recovers. High infection risk because the catheter is outside the skin and accessible.
Permanent/long-term central venous catheter (Permacath): lower infection risk relative to VAScath but still carries infection risk; can stay in place longer (often up to a year or more) if needed.
Context: In the transcript, vas caths are described as temporary and higher risk; Permacath may stay longer but infection risk remains.
Other context: A patient with AKI from sepsis may require dialysis acutely (as in the aunt example) but may recover, in which case temporary access can be removed.
Insertion risks and monitoring
Insertion risk to the lungs: pneumothorax can occur when inserting central lines near the chest; risk monitored by chest X-ray after placement.
Monitoring during and after insertion: assess for signs of pneumothorax (shortness of breath, chest pain); ensure imaging clears the line before use.
Nursing scope during insertion: sterile technique; the dialysis nurse or trained ICU/med-surg staff clears and uses the line; main responsibility is maintaining sterility and confirming clearance with imaging prior to use.
Site care: keep the catheter site sterile; do not water-wet the site; avoid contamination.
Central line maintenance and nursing care
Sterile technique is paramount at all times; the hub should be scrubbed before any access.
If the line is not being used, do not flush it routinely; when needed, dialysis nurses perform the access.
Competency requirements: dialysis nurse competencies (post-graduate checks) allow use of Vascath; general ICU/Med-Surg staff may have different scopes.
Typical nursing actions: monitoring for infection, occlusion, and function; ensure connections remain sterile; notify physician or dialysis team if problems arise.
Occlusion and mechanical issues
Possible problems with central lines affecting dialysis access: occlusion, collapse, or clot formation can occur.
Everyday analogies: central line functions resemble a large IV line; occlusion is a common problem if the line is not patent.
AV fistula vs AV graft: definitions and anatomy
AV fistula:
Created by surgically connecting an artery to a vein using the patient’s own vessels (no synthetic material).
The access is under the skin; no external conduit after healing.
Pros: longest lifespan, lowest infection risk, best long-term outcomes; ideal option when feasible.
Cons: requires suitable vasculature and time to mature before use; not every patient has anatomy suitable for a fistula.
AV graft:
Synthetic material connects an artery to a vein under the skin when native vessels are inadequate.
Requires two needle sticks per dialysis session (one in each access limb, arterial and venous sides).
Pros: usable earlier than a fistula if vessels are poor; life-saving when a fistula is not feasible.
Cons: higher risk of complications than a fistula (e.g., infection, stenosis, occlusion); less ideal than a natural fistula for longevity.
Key difference: fistula uses native vessels (no implanted material); graft uses synthetic material.
Clinical takeaway: both can provide lifelong access, but fistulas generally have fewer complications and longer longevity when possible.
Pros and cons of AV fistula vs AV graft
Fistula pros:
Minimal infection risk (no synthetic material exposed).
Lifelong potential with proper care.
Lower maintenance and fewer interventions over time.
Fistula cons:
Not every patient has suitable vasculature; maturation takes weeks to months and may fail to mature.
Graft pros:
Can be used earlier if vessels are inadequate for a fistula.
Useful when anatomy is unfavorable for a fistula.
Graft cons:
Higher risk of infection and occlusion than fistula; more interventions may be needed.
External appearance and wear can cause body image concerns; potential for pseudoaneurysm with punctures.
Both can be lifelong but fistula generally preferred when feasible.
Access assessment and maintenance (nursing priorities)
Daily assessment: check for a palpable thrill and auscultate for a bruit to assess patency of AV access.
Thrill: feel for a fluttering, “cat-purring” sensation over the access site.
If thrill or bruit is absent, escalate to the physician or dialysis team for further evaluation.
No blood pressures or venipunctures on the access arm (for AV fistula/graft) to prevent damage.
Protect the access arm from heavy lifting, constrictive clothing, or trauma.
Call the physician/dialysis team if there are signs of compromised access (no thrill/bruit, swelling, infection signs).
Peritoneal dialysis (PD): Tenckhoff catheter and process
Access: Tenckhoff catheter (abdominal) is used for PD; no external catheter in the chest like some CVCs.
Mechanism: Dialysate is infused into the peritoneal cavity; peritoneal membrane acts as the semipermeable membrane for diffusion/osmosis; dialysate is then drained out.
PD process (CAPD and APD variations):
CAPD (continuous ambulatory PD): multiple exchanges per day (e.g., 5–6 times daily) with manual infusions.
APD/CCPD (automated PD): exchanges performed overnight with a cycler pump.
PD procedure in the hospital:
Infusion: open the clamp, let dialysate flow into the abdomen; dwell time typically around 20{-}30 ext{ min} (or longer, per order).
Drain: open the drain clamp to let used fluid exit; duration depends on volume; total exchanges may take 30{-}45 ext{ min} per cycle.
Overall, a PD session resembles a continuous bladder irrigation setup in its sequence of infusions and drains.
Pros of PD:
Can often be done at home; high independence; few dietary restrictions; greater flexibility.
Mimics normal urination in terms of daily burden and independence.
Ability to set own schedule (including overnight options).
Cons of PD:
Infection risk: peritonitis is a major concern; early recognition is critical.
GI issues: constipation and abdominal discomfort; more environmental and hygiene vigilance required.
Not all patients tolerate PD well; some may fail and transition to hemodialysis.
Requires diligent patient/caregiver training and adherence to sterile technique; meticulous care of connections and catheters.
Peritonitis signs: rigid abdomen; cloudy effluent; pink/yellow effluent or debris can indicate peritonitis.
Advantages of home PD: greater independence, fewer clinic visits, more liberal fluid and dietary allowances.
Considerations for choosing PD: patient preference, lifestyle, peritoneal anatomy, and ability to perform exchanges safely.
Continuous Renal Replacement Therapy (CRRT)
Definition: continuous renal replacement therapy; a type of hemodialysis used in the ICU for critically ill, unstable patients.
Key features:
Runs continuously (24/7) with slow blood purification, as opposed to the intermittent, rapid exchanges of conventional HD.
Indicated for patients who cannot tolerate rapid fluid shifts or large-volume dialysis due to instability.
Accessibility setting: CRRT is not used in ER, med-surg floors, or typical dialysis clinics; it is reserved for ICU patients.
Clinical takeaway: CRRT is a specialized, ICU-only modality and represents a continuation of hemodialysis principles in a continuous, gentle form.
Hemodialysis basics (overview and workflow)
Concept: hemodialysis as the artificial kidney—blood is removed, filtered, and returned to the patient.
Frequency and duration (standard):
Typically performed three times per week, each session lasting 3{-}4 ext{ hours} depending on the amount of fluid to remove.
Dry weight vs wet weight:
Wet weight: the patient’s pre-dialysis weight with all fluid on board.
Dry weight: the target post-dialysis weight when fluid is at an acceptable level between dialysis sessions.
Fluid removal strategy is patient-driven and based on how the patient feels and tolerates dialysis.
Fluid management:
The goal is to achieve a dry weight that maintains adequate breathing and avoids fluid volume overload or deficit.
The calculation typically converts weight difference into the amount of fluid to remove: if weight is given in pounds, convert to kilograms to determine mL of fluid to remove.
Practicalities:
If too much fluid is removed, the patient may feel unwell; adjustments to the dry weight are made accordingly.
Dialysis staff use the patient’s feedback and physiologic responses to tailor each session.
Dialysis access care in HD: two needles are used during each session (arterial and venous) for blood withdrawal and return.
Outcomes: dialysis helps manage volume and electrolytes, and can even deliver medications (e.g., antibiotics) through the dialysis circuit when needed.
Peritoneal dialysis (PD) vs HD: key distinctions
PD uses the peritoneal membrane as the filtering surface, while HD uses an external machine to filter blood.
PD access (Tenckhoff catheter) is internal; HD accesses (AV fistula/graft or catheter) are external or internal to the body but accessed via blood vessels.
PD process is patient-driven and home-based, while HD is clinic- or hospital-based with scheduled sessions.
Quick reference: infection risks by access type
BAS cath (temporary central line): higher infection risk; short-term use (2–3 weeks typical) unless recovery fails.
Permacath (permanent central line): lower infection risk than BAS cath but still significant; allowed to stay longer if needed.
AV fistula/graft: infection risk is relatively low, with fistulas particularly preferred; grafts still carry infection risk but usually lower than central venous catheters.
PD: peritonitis is the main infection risk, requiring prompt recognition and management.
Practical implications and patient education themes
For patients with AV access (fistula/graft):
Protect the limb; avoid BP cuffs, IV sticks, or heavy lifting on the access arm; monitor for signs of infection or blockage.
Teach patients to report absence of thrill/bruit or changes in skin color, warmth, or swelling.
For PD patients:
Emphasize sterile technique during exchanges; protect the catheter exit site from infection.
Be aware of signs of peritonitis (rigid abdomen, cloudy effluent, abdominal pain) and seek prompt care.
Understand possible GI and abdominal effects (constipation, flatulence, abdominal distension) and the impact on activities.
For all dialysis modalities: recognizing and responding to infection risk, maintaining proper site care, and understanding the lifestyle implications (diet, fluid restrictions, activity limitations).
Real-world example from the transcript
A family member contracted a severe infection (salmonella leading to sepsis) and developed AKI, requiring dialysis with three dialysis sessions. This illustrates how temporary access can be necessary during AKI and the potential for recovery and removal of temporary devices, avoiding permanent disfigurement if recovery occurs.
Summary of key numerical references (LaTeX formatted)
Temporary BAS cath infection risk window: 2{-}3 ext{ weeks}
Permacath potential duration: up to 1 ext{ year} (approximate; infection risk remains)
Hemodialysis standard schedule: 3 ext{ times/week}, duration 3{-}4 ext{ hours} per session
AV fistula/graft needle sets per dialysis: 2 ext{ needles} per session
HD flow reference: ext{flow}
ightarrow 400 rac{ ext{mL}}{ ext{min}}PD dwell and drain timing examples: 20{-}30 ext{ min} dwell; 30{-}45 ext{ min} drain per cycle
PD catheter: Tenckhoff catheter (abdomen)
PD infection risk: peritonitis (major concern)
Dry weight concept: wet weight W{ ext{wet}} vs dry weight W{ ext{dry}}; fluid removal V approximately as:
If weights in pounds: V \approx (W{ ext{wet}}-W{ ext{dry}}) \times 454 ext{ mL}
If weights in kilograms: V \ = (W{ ext{wet}}-W{ ext{dry}}) \times 1000 ext{ mL}
Notes
The material reflects a clinical lecture-style overview of dialysis access options, their pros/cons, nursing care, and the basics of HD, CRRT, and PD.
Always refer to current clinical guidelines for exact durations and device-specific recommendations, as practices may vary by institution and patient-specific factors.