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Fact file principles of fluid management
- 1. Fact file Preeclampsia : Principles in Fluid management Dr Ajay S Dhawle Asst Professor JNMC Sawangi (Meghe) Wardha
- 2. Understanding the Basics: Total Body Water
- 3. Forces important in balancing the fluid distribution: • Hydrostatic pressure: Difference between the pressure at the arteriolar end and the venular end of a capillary • Colloid osmotic pressure: Pressure exerted by the intravascular proteins which retains fluid inside • Capillary permeability • Interstitial lymphatic drainage:
- 4. Parameter Non pregnant Pregnant Preeclampsia SVR (dyne/cm/sec) 1530 ± 520 1210 ± 266 (-21%) Colloid osmotic 20.8 ± 1.0 18.0 ± 1.5 (-14%) pressure Capillary - permeability Pre eclampsia 8-10 26-28 64 Intravascular Compartment Interstitial Pregnant 12 24 64 Compartment Intracellular Compartment Non Pregnant 8 26 66 0% 20% 40% 60% 80% 100%
- 6. Why? Forced Diuresis ‘DRY’ management Renal Protection Lung protection
- 7. The Forced Diuresis theory • Preeclampsia -decreased intravascular volume • Renal dysfunction is a norm rather than an exception • Oliguria -common feature & marker of renal function • It is tempting to ‘fill up’ the intravascular space with a fluid challenge and/ or use diuretics to force the urine out.
- 8. Deaths Triennium • Tried in the Uk in the late ICH Pulmonary eighties and early nineties 1982-84 13 03 • CEMACH Report 1991-93: 1985-87 11 10 Pulmonary complications 1988-90 12 10 outstripped the deaths from ICH in a ratio of 2:1 1991- 93 05 11 1994-96 04 08 • Swing towards ‘fluid 1997-99 07 02 restriction’: Pulmonary deaths 2000-02 09 01
- 9. What we now know: • Though renal dysfunction is ubiquitous, renal failure is uncommon • Recovery rates in short to medium term : very High • No residual impairment • Oliguria does not necessarily indicate fluid depletion Renal Failure is a significant threat only if preeclampsia is associated with Abruptio, HELLP, IUD & DIC
- 10. Some facts : • Pulmonary edema : ~ 2.9% of patients with severe preeclampsia • Preeclampsia is the admitting diagnosis in 18–28% of pregnant patients presenting with pulmonary edema • Preeclampsia associated with pulmonary edema: significant maternal (11%) and perinatal (9– 23%) mortality rates • 70 % of the cases occurred postpartum, 72 hours after delivery • Pulmonary edema usually occurs as a part of multi- system disorder rather than an isolated complication.
- 11. Fluid management in preeclampsia • Strict monitoring of the Input- output status • Renal function test • Most patients DO NOT require ICU care or invasive monitoring • Restrict fluids- approx 80ml/hour - 1 ml/kg/hour • Use pediatric microdrip sets (at 64drops/min, deliver 60ml/hr) in the absence of infusion pumps • Oxytocin: ADH properties- fluid retention Use concentrated infusion drip (infusion set/ micro drip set)
- 12. Preloading for spinal anaesthesia (SA) • Regional anesthesia : the method of choice for cesarean deliveries due to its proven record of maternal and fetal safety (Hawkins JL, Koonin LM, Palmer SK, et al. Anesthesia related deaths during obstetric delivery. Anesthesiology 1997;86:277– 84) • Preeclamptic women : depleted intravascular volume & decreased uteroplacental perfusion. • SA: rapid sympathetic blockade and profound hypotension • Additive hypotension : the vasodilatory actions of magnesium and the use of antihypertensives like labetalol • Despite these concerns, recent evidence indicates that spinal anesthesia may be safely used with no adverse maternal or fetal sequelae (Hood D, Curry R. Spinal versus epidural anesthesia for cesarean section in severely preeclamptic patients. Anesthesiology 1999;90:1276–82.)
- 13. Consensus: • Patients with mild pre-eclampsia do not need any special monitoring and will tolerate prophylactic hydration. • In most instances, patients with severe preeclampsia can be similarly managed, especially if the urine output is adequate.
- 14. Oliguria • If the urine output is inadequate, a fluid challenge is done with 250 to 500 mL of crystalloid infused over 20 minutes. • If the patient responds with an increase in urine output, additional fluid boluses may be given cautiously before the regional block. • If there is no response to the initial fluid bolus, CVP or PCWP monitoring becomes necessary.
- 15. Invasive monitoring PCWP: measures the LA pressure correlates with diastolic filling CVP: measures the RA pressure (preload of the left heart) correlates with intravascular volume or hydrostatic pressure in the pulmonary capillaries The need for invasive monitoring of filling pressures is seen in very specific cases: •Severe Oliguria, not responding to fluid challenge, Anuria, ARF •Uncontrolled HTN •Pulmonary edema
- 16. • Volume expansion to CVP of at least 6 to 8 mm Hg is generally considered to be safe and effective. • However, the CVP–PCWP gradients in severe pre-eclampsia may be as high as 8 to10 mm Hg. (Therefore, a CVP of 8 mm Hg might correspond to a PCWP as high as 18 mm Hg.) This results in volume overload and possibly pulmonary edema. • In a study of 50 patients with pre-eclampsia, Wallenburg et al showed that none of the patients with a CVP of 4 mm Hg or less had PCWP values exceeding 12 mm Hg [52]. (Wallenburg HCS. Hemodynamics in hypertensive pregnancy. In: Rubin PC, editor. Handbook of hypertension. The Netherlands: Elsevier; 1988. p. 66– 101) • Therefore, if CVP alone is being monitored for fluid management, volume expansion to achieve a CVP of 4 mm Hg or less is sufficient [18].
- 17. Typical volemic effects of different intravenous fluids after 1 ltr infusion
- 18. Crystalloids/ Colloids • Crystalloids: usually the first choice for preloading. In theory, volume expansion: further reduction the COP. therefore, it would be advantageous to use colloid for volume expansion. • A review comparing albumin for volume expansion in NON pregnant women concluded: albumin increased the risk of death (Cochrane Injuries Group Albumin Reviewers. Human albumin administration in critically ill patients: systematic review of randomized controlled trials. BMJ 1998;317:235– 40.) • Also, increased mortality was associated with the use of colloid for resuscitation when compared with crystalloid. (Alderson P, Schierhout G, Roberts I, et al. Colloids versus crystalloids for fluid resusitation in critically ill patients. (Cochrane Review). In: The Cochrane Library, Oxford: Update Software. Issue 1, 2003.) • At this time, there is insufficient evidence to choose colloid over crystalloid in patients with pre-eclampsia . (Bolte AC, Geijn HP, Dekker GA. Management and monitoring of severe pre-eclampsia. Eur J Obstet Gynaecol Reprod Biol 2001;96:8–20.) • If large volumes of colloid are chosen for hydration, invasive monitoring of filling pressures is recommended
- 19. Summary: RCOG Guideline No 10 A
- 21. Thank You
- 22. What happens during a pregnancy?
- 26. Thank you
Editor's Notes
- 50% of total body weight in an average female is body water. Given that, total blood volume increases by 50% during pregnancywith only 20% of that increase attributed to an increase in red cell mass, one can extrapolate that 60% to 65% of the total body weight in pregnancy can be attributed to TBW. The intracellular fluid compartment (ICF) contains 66% of TBW. The extracellular compartmentis composed of 34% TBW. Most of the extracellular fluid compartment is interstitial (26%), plasma composes 8%. The fluid compartments are separated by semipermeable membranes. Water and smaller molecules may pass through the membranes; larger colloid substances and proteins are confined to the intravascular space.
- Now lets see what happens during the course of a normal pregnancy and in preeclampsia. In normal pregnancy, the SVR decreases, as does the Colloid osmotic press. During preeclampsia, the decrease in SVR doesnot take place & in severe cases it may even be increased, this is also associated with endothelial dysfunction leading to increased capillay permeability, and a further decrease in the COP due to proteinuria. All of these translate into the typical changes in the ratio of Interstitial and IVF compartments, with an increased propensity to oedema. In mild pre-eclamptics, plasma volume is 9% lower than normotensive pregnant women, and in severe pre-eclampsia is further reduced by 30% to 40%.
- This is the mythical story of two monsters- Scylla & Charybdis who guarded the sea…. The sailors needed to maintain a delicate balance so as to not venture close enough to either of them or face dire consequences.
- In Preeclampsia, the two monsters are renal failure and the pulmonary edema. The need for a discussion about the principles of fluid management has stemmed from the fact that two diametrically opposite philosophies have been proposed – the fluid loading and forced diuresis theory and the theory of ‘dry’ management.
- The renal rescue protocol was tried in the Uk in the late eighties and early nineties. Until then, Intracranial hemorrhage had been the major contributor to maternal deaths in Preeclampsia, accounting for almost 75% of the deaths. CEMACH 91-93: situation had reversed with pulmonary complications outstripping ICH, With this realization, there was again a swing towards fluid restriction, which promptly decreased the number of pulmonary deaths.
- Around the time of delivery, Oliguria may be due to glomerularendotheliosis, or more often simply a response to physiological stress mediated through AVP released from posterior pituitary, which causes fluid retention), and is usually followed by a period of spontaneous diuresis post delivery.
- The maternal mortality rate directly related to anesthesia is approximately 16 times greater in thosereceiving general anesthesia compared to those receiving regional anesthesia [55]
- Although colloids are retained inside the Intravascular compartment longer (3-4 hours), In preeclampsia the increased capillary permeability causesthe proteins to gradually leak out into the extravascular space, greatly increasing the chances of a delayed interstitial edema.
- Maintaining fluid balance in severe preeclampsia is like standing between the devil and the deep blue sea. With adequate care, knowledge and skill, we may find however, that it is possible to escape both….