CRRT (Continuous Renal Replacement Therapy) at KIMS Secunderabad — 24/7 ICU Dialysis for Acute Kidney Failure
At a glance — CRRT at KIMS
- What CRRT is: A slow, continuous form of kidney replacement therapy delivered 24 hours a day in the ICU — specifically designed for critically ill patients whose blood pressure is too unstable to tolerate standard intermittent haemodialysis
- Availability at KIMS: 24 hours a day, 7 days a week — including immediate initiation for emergency AKI in the ICU
- Most important clinical fact: Acute Kidney Injury (AKI) — the most common reason for CRRT — frequently recovers with appropriate treatment. Most patients treated with CRRT for AKI do not develop permanent kidney failure. CRRT buys time for the kidneys to heal.
- Lead nephrologist: Dr. E. Ravi — Senior Nephrologist, DM Nephrology (Rank 1 statewide 2009) — critical care nephrology and acute dialysis expertise
- Critical care infrastructure: KIMS is a 1,000-bed hospital with full ICU infrastructure — ventilators, vasopressors, invasive haemodynamic monitoring — managed alongside CRRT without transfer
- Trajectory management: Transition to HD and transplant pathway managed on same campus
- Appointments: 040 - 44885000 (Emergency)
What is CRRT and why is it used in the ICU?
When a critically ill patient develops acute kidney failure — whether from sepsis, major surgery, severe dehydration, a drug reaction, or any other cause — the kidneys stop filtering blood adequately. Toxins and fluid accumulate rapidly. Kidney replacement therapy must begin. But standard haemodialysis, which removes several litres of fluid over 4 hours at high blood flow rates, causes abrupt shifts in blood pressure and fluid balance that a haemodynamically unstable ICU patient cannot safely tolerate. In a patient already on vasopressors (medications to maintain blood pressure), a sudden drop in blood pressure from HD can be fatal.
Continuous Renal Replacement Therapy (CRRT) solves this problem by performing dialysis slowly and continuously — 24 hours a day, removing fluid and waste products at a rate of millilitres per hour rather than litres per session. Blood is drawn from a central venous catheter, passed through a haemofilter at low flow rates (100 to 200 ml per minute — compared to 300 to 400 ml per minute in standard HD), and returned continuously. The gentle, gradual removal of fluid and solutes produces minimal cardiovascular stress, allowing kidney replacement to proceed safely even in patients on ventilators, vasopressors, and multiple ICU medications.
Acute Kidney Injury — the condition that most commonly requires CRRT — is frequently reversible. When the underlying cause (sepsis, dehydration, drug toxicity, obstruction) is identified and treated, the kidneys often recover their function over days to weeks, and CRRT can be discontinued. Most AKI patients who receive timely CRRT do not develop permanent kidney failure. CRRT is not a permanent treatment — it is a temporary bridge that keeps the patient alive while the kidneys heal.
When is CRRT indicated?
CRRT is used for critically ill patients in the ICU when kidney replacement therapy is needed but standard intermittent haemodialysis is not safe due to haemodynamic instability. The specific clinical indications at KIMS include:
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Haemodynamically unstable AKI — the patient is on vasopressors (noradrenaline, vasopressin) or has a MAP below 65 mmHg consistently, making standard HD unsafe
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Sepsis-associated AKI — the most common cause of ICU AKI. Sepsis causes inflammatory kidney injury; CRRT removes inflammatory mediators (cytokines) as well as conventional waste products
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Post-cardiac surgery AKI — cardiac surgery patients with acute kidney failure requiring a haemodynamically gentle approach
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Post-trauma AKI — major trauma with multi-organ dysfunction including acute kidney failure
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Drug-induced AKI — nephrotoxic medications (contrast agents, aminoglycoside antibiotics, NSAIDs in susceptible patients) causing acute tubular necrosis
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Severe fluid overload with oliguria — pulmonary oedema in a patient too unstable for rapid fluid removal by standard HD
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Severe refractory hyperkalaemia — life-threatening potassium elevation requiring immediate and sustained removal
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Hepatorenal syndrome — kidney failure in the context of severe liver disease, where haemodynamic instability is profound
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AKI in patients with raised intracranial pressure — CRRT avoids the osmotic shifts of standard HD that can worsen cerebral oedema
How CRRT works — the four modalities
CRRT is available in several modalities — the choice between them depends on the clinical priority: primarily solute removal, primarily fluid removal, or both equally. At KIMS, the modality is selected by the nephrologist based on the specific clinical scenario:
| CRRT modality | Mechanism · Primary clinical use |
|---|---|
| CVVH (Continuous Veno-Venous Haemofiltration) | Mechanism: Convective transport — substitution fluid infused, equivalent volume removed. No dialysate. Best for: fluid removal and mid-molecular solute clearance — sepsis, fluid overload, cytokine removal. |
| CVVHD (Continuous Veno-Venous Haemodialysis) | Mechanism: Diffusive transport — dialysate flows countercurrent across membrane. Best for: small solute removal — urea, creatinine, electrolyte management. |
| CVVHDF (Continuous Veno-Venous Haemodiafiltration) | Mechanism: Combined diffusion and convection — dialysate and substitution fluid both used. Best for: comprehensive clearance of both small and mid-molecular solutes. Most commonly used in critically ill AKI. |
| SCUF (Slow Continuous Ultrafiltration) | Mechanism: Pure fluid removal — very slow ultrafiltration, minimal solute clearance. Best for: isolated severe fluid overload (pulmonary oedema) where solute clearance is not the primary need. |
CRRT vs intermittent haemodialysis — why CRRT for ICU patients
| Feature | CRRT | Intermittent HD |
|---|---|---|
| Duration | 24 hours continuous | 4 hours, 3x per week |
| Blood flow rate | 100–200 ml/min (gentle) | 300–400 ml/min (rapid) |
| Fluid removal rate | Slow — ml per hour | Rapid — litres per session |
| Blood pressure stability | Excellent — gentle fluid shifts | Risk of hypotension especially in unstable patients |
| Vasopressor compatibility | Safe | Risk of decompensation |
| ICU compatibility | Specifically designed for ICU use | Can be done in ICU but less well tolerated |
| Cerebral oedema safety | No osmotic shifts — safe | Osmotic shifts may worsen cerebral oedema |
| Anticoagulation | Regional citrate or low-dose heparin — carefully managed | Systemic heparin |
| When to transition to HD | Continued until patient haemodynamically stable, then transition to HD | Used once patient stable enough |
Can kidney function recover after CRRT?
For AKI patients — the majority of CRRT recipients — kidney recovery is not just possible but common. The underlying cause of AKI determines the likelihood and timeline of recovery:
By Recovery Type:
- Sepsis-associated AKI: Kidney function frequently recovers once the sepsis is controlled and the haemodynamic situation stabilises. Recovery typically occurs over 7 to 21 days.
- Post-surgical or post-trauma AKI: AKI following major surgery or trauma is often caused by acute tubular necrosis from ischaemia. Tubular cells regenerate over 1 to 4 weeks.
- Drug-induced AKI: When the offending nephrotoxic agent is identified and stopped early, recovery of tubular function is frequent, sometimes within days.
- Progression to ESRD (a minority): Where AKI does not recover, the patient transitions from CRRT to intermittent haemodialysis and transplant evaluation.
Family Guidance:
If your family member is on CRRT in the KIMS ICU, ask the nephrologist specifically about urine output trends and creatinine trajectory. These are the earliest signs of kidney recovery — and the KIMS team tracks them at every daily ICU round. Even a small increase in urine output (from near-zero to 100–200 ml per day) is a clinically meaningful sign of early tubular regeneration.
Why KIMS Secunderabad for CRRT?
24/7 availability — no transfer, no delay
AKI requiring CRRT is a medical emergency. KIMS operates CRRT around the clock — a patient admitted at 2am with AKI requiring dialysis does not wait for a morning shift. The CRRT machine is initiated immediately.
Critical care nephrology expertise — Dr. E. Ravi
Acute kidney injury in the ICU requires a nephrologist who understands multi-organ dysfunction. Dr. E. Ravi — DM Nephrology (Rank 1 statewide) — leads the KIMS critical care nephrology programme, with specific expertise in AKI management.
Complete ICU infrastructure on one campus
A CRRT patient is typically on a ventilator and vasopressors. KIMS is a 1,000-bed hospital with full tertiary ICU infrastructure. There is no need to transfer an AKI patient; we provide all critical care on the same campus.
Full trajectory management
KIMS does not hand patients off. The transition from CRRT to intermittent HD, from HD to recovery monitoring, or from HD to transplant evaluation is all managed by the same KIMS nephrology team.
Our CRRT and critical care nephrology team at KIMS Secunderabad
Frequently Asked Questions
CRRT (Continuous Renal Replacement Therapy) is a slow, continuous form of kidney replacement therapy designed specifically for critically ill patients in the ICU whose blood pressure is too unstable to tolerate standard intermittent haemodialysis. Standard HD removes 2 to 3 litres of fluid over 4 hours at high flow rates, which can cause blood pressure drops. CRRT works 24 hours a day at much lower flow rates, producing negligible cardiovascular stress even in patients on vasopressors.
In many cases, yes. CRRT is most commonly used for Acute Kidney Injury (AKI) which is frequently reversible. When the underlying cause (sepsis, surgery, drug toxicity) is treated, the kidney's tubular cells regenerate and function recovers over days to weeks in many patients. CRRT keeps the patient alive during this recovery period. The KIMS team monitors urine output and creatinine daily for early signs of recovery.
Standard haemodialysis involves rapid fluid removal and blood flow rates that cause blood pressure drops in many patients — this is manageable in a stable patient but dangerous in a critically ill patient already on vasopressors. In a patient whose blood pressure is maintained artificially by noradrenaline or vasopressin infusions, the blood pressure drop triggered by HD can cause circulatory collapse. CRRT avoids this by removing fluid and waste products slowly and continuously.
The duration of CRRT varies from days to several weeks, depending on the underlying cause of AKI and the rate of kidney recovery. Sepsis-associated AKI often recovers within 1 to 3 weeks. Post-surgical AKI may resolve within 7 to 10 days of tubular regeneration. The KIMS nephrology team reviews CRRT requirements daily at ICU rounds.
No — patients on CRRT in the ICU are typically unconscious, sedated, or minimally conscious due to their critical illness. The CRRT circuit connects to an existing central venous catheter. There is no additional needle placement, no discomfort from the dialysis circuit itself, and no blood pressure drops to cause distress.
The main clinical risks are actively managed: clotting of the CRRT circuit (managed with anticoagulation); electrolyte disturbances (KIMS replaces these proactively through substitution fluid); hypothermia (managed with fluid warmers); and infection at the catheter site (managed with strict aseptic technique). CRRT is very well tolerated in the experienced hands at KIMS.
Not necessarily — and often not. For patients with AKI who recover kidney function, CRRT is stopped and no long-term dialysis is needed. For patients whose AKI does not recover, KIMS transitions from CRRT to haemodialysis or peritoneal dialysis and begins transplant evaluation for eligible candidates.
KIMS Secunderabad — 24/7 CRRT availability with immediate initiation, led by Dr. E. Ravi (DM Nephrology Rank 1 statewide), full ICU infrastructure on the same campus (no transfer needed), complete trajectory management from acute crisis to transplant recovery, and 1,500+ transplants performed. NABH and NABL accredited.