CRRT: More than renal replacement, a case study in multiple organ support

Bala Sri1, Melhi2

1Dialysis Technician, Kauvery Hospital, Hosur

2Dialysis Technician, Kauvery Hospital, Hosur

Abstract

This case study describes the uses of CRRT in critically ill patient with Acute on Chronic kidney disease, septic shock, multiple organ dysfunction, type 2 diabetes mellitus, presumed  diabetic nephropathy and , RVD seropositive,  from the perspective of dialysis technologist

CRRT

  • CRRT is a extracorporeal blood purification therapy. It is a slow and continuous process of removing excess fluid, toxins and waste products from the blood and restoring electrolytes and acid base balance
  • CRRT is performed continuously over a period of 24 hours a day

Principle

Diffusion

It is the process of solute move from an area of higher concentration in blood to an area of lower concentration,  in the dialysate across the semipermeable membrane

Ultrafiltration

Fluid is forced across the semi-permeable membrane from an area of high pressure ( blood )  to low pressure (dialysate)

Convection

It is the process of  removal from the blood as they are dragged across a semi-permeable membrane by the flow of water

Modalities of CRRT

 CVVH – Continuous Veno-Venous Hemofiltration

  • Principle : Convection
  • Removal :   Solutes , middle and large molecules , large amount of fluids
  • Dialysate : Not required
  • Replacement fluid: Required
  • Focus : Efficiently remove water ,urea , creatinine, salt and middle size  molecules
  • Indication : Uremia, Severe acid base or electrolytes imbalances
  • PH Correction : Available

CVVHD – Continuous Vono-Venous Hemodialysis    

  • Principle : Diffusion
  • Removal : Solutes and water ,small molecules
  • Dialysate : Required
  • Replacement fluids : Not required
  • Focus : Effective for removing small to medium sized molecules and controlling electrolytes imbalance
  • Indication : Acute brain injury , Lactic acidosis, Sepsis and Multiple organ failure
  • PH : Available

CVVHDF – Continuous Veno-Venous Hemodiafiltration

  • Principle : Diffusion, Ultrafiltration, Convection
  • Removal : Water , Small Molecules
  • Dialysate : Required
  • Replacement Fluid : Required
  • Focus : Enhanced Clearance Of Solute, Superior Control Over Acid Base Balance
  • Indication : Intoxication , Severe Hyperammonemia , Acute Brain Injury , Hemodynamic Instability
  • PH Correction : Available

SCUF – Slow Continuous Ultrafiltration

  • Principle : Ultra Filtration
  • Removal : Water
  • Dialysate : Not Required
  • Replacement Fluid : Not Required
  • Focus : To achieve safe and effective treatment of fluid overload in patient who are hemodynamically unstable, who have severe fluid overload with and without renal failure
  • Indication : Fluid Overload, Acute Kidney Injury, Congestive Heart Failure
  • PH Correction : Not Available

AdvantagesDisadvantages
Slow fluid removalHigher cost and labour intense
Reduced fluctuations in toxins levelRequired specialized equipment and training
Removal of large solutes like myoglobulin, cytokinaseCan be less convenient and time consuming
Low risk of complicationsNot as good in hyperkalemia as hemodialysis

Case Study

  • 60 years male patient present to ER on 17/06/2025  with  urinary incontinence since Jan – 2024 after TURP + BNI
  • C/o Burning micturition
  • H/o vomiting
  • H/o supra pubic pain
  • No H/o dysuria / hematuria
  • K/C/O Type 2 DM for the past 15 years on regular medication
  • K/C/O CKD on medical management
  • N/K/C/O CAD   / BA / Epilepsy / TB

On Examination

  • Patient conscious, Oriented, Febrile
  • BP : 170 / 100  mmHg
  • PR : 153 b/ min
  • RR : 24  b / min
  • Temperature : 104 .2  f
  • SpO2 : 97 %
  • CVS : S1S2 (+ )
  • RS : BLAE (+)
  • PA : Soft Non tenders
  • CNS : NFND

Course in the hospital

Patient was admitted in ward for further management. Patient was started on IV antibiotics, diuretics and other supportive measures. Relevant investigations were done.

Lab investigation

InvestigationResult
Hb10.6 g/dl
TC3600/Cumm
Platelet153000 / Cumm
PTT14.3 sec
PT11.4 sec
INR1.26
Total Bilirubin0.9 mg/dl
SGOT64 U/L
SGPT47 U/L
Na+139 mmol/L
K+4.2 mmol/L
Urea62.1 mg/dl
Creatinine3.9 mg/dl
T30.539 g/ml
T43.38 g/dl
TSH1.254 mIU/L
PSA total0.546
HbA1c7.5 %
PH7.36
PCO229 mmHg
PO225 mmHg
HCO316.4 mmol/L
Lac4.3 mmol/L
HBsAgNon-reactive
HCVNon-reactive
HIVNon-reactive

CT KUB

  • Both kidneys are bulky and edematous with perinephric inflammatory changes S/O Bilateral pyelonephritis, Mild dilation of right pelvicalyceal system with no e/o ureteric calculus
  • Cholelithiasis , Multiple enlarged left renal hilar lymph nodes noted, No E/O free fluid in abdominal and pelvis .

ECHO

  • Suboptimal poor Echo window
  • Tachycardia during study @ HR – 120 b / min
  • Mild concentric left ventricular hypertrophy you
  • No Regional wall Motion Abnormality
  • Good LV systolic Function ( LVEF – 60 %)
  • Diastolic Dysfunction Grade 1
  • Trivial Aortic Regurgitation

In the view of hypotension and desaturation patient shifted ICU in the support of inotrope and oxygen for further management. Onhe evaluation, was found to be seropositive and started antiviral. Patient was initiated on dialysis through Right IJV temporary catheter in view of anuria despite diuretics. He underwent Cystoscopy + Bilateral DJ stenting under IVS on 18/06/2025. Post operatively 3 units platelet transfusion done .

Intra Op Finding

  • Meatus – Adequate
  • Urethra – normal
  • S/P TURP – Post TURP change
  • Bladder neck – Distorted
  • Trigone – normal
  • B /L UO – Visualized
  • Bladder – Debris ( +  )
  • Right RGP : Right PCS dilation (+), purulent efflux (+)
  • Left RGP : Left PCS dilation (+), purulent efflux (+).

Hypotension worsened during Hemodialysis hence CRRT started.

CRRT Prescription

  • Mode :  CVVHDF
  • Access :  Right Inter Jugular Catheter
  • Machine Used : Prisma Flux
  • Filter Set : M 100
  • Blood flow : 80 ml / min
  • Dialysate flow – 1600 ml /hour
  • Pre blood pump -550 ml /hour
  • Replacement fluid – 250 ml /hour
  • Ultrafiltration – 30 ml /hour
  • Total dose – 2400

No anticoagulant

CRRT started with above the orders , glycemic level monitored  regularly ,with 48 hours urine out began to improve, and hypotension improved so CRRT discontinued after 50 hours

On improvement of general condition patient shifted to ward and managed with IV antibiotics, antiviral, diuretics, ulcer protectives, reno protectives, vitamins and calcium supplements and other supportive measures.  Patient became symptomatically better, Cr and Urine output improved. Hence patient was discharged.

How CRRT Plays a Major role in this case

  • On this case patient was diagnosed with multiple organ dysfunction who was hemodynamically unstable, CRRT slowly removes excess fluid which helps to maintain the patient’s blood pressure
  • Effectively remove uremic toxins, inflammatory mediators which accumulated in the blood
  • CRRT stabilized the patient‘s blood environment , which supports the other vital organs such as heart, brain , lungs in additional kidney.
  • On the whole CRRT is not a life-threatening procedure. When it’s started on the Right time, it saves patient’s life .

Conclusion

From my perspective as a dialysis technologist

“CRRT IS MORE THAN JUST RENAL REPLACEMENT THERAPY”

It is a form of multiple organ support in critically ill patients with conditions like sepsis, multiple organ dysfunction, fluid overload etc. CRRT plays vital role in stabilizing the internal environment by continuously removing excess fluid, correcting acidosis, clearing inflammatory mediators and maintaining electrolytes balance. This is how CRRT indirectly supports the lungs, liver, heart and brain.

 

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