Reference: NYPH ICU Manual, July 2002


Hemodynamics

Cardiac Output (Q)= HR x SV Cardiac Index (Qi)= Q/ Body Surface Area(BSA) Systemic Vascular Resistance (SVR)= (MAP-CVP)80/Q Pulmonary Vascular Resistance (PVR) = (MPAP-PAOP)80/Q DO2 = CaO2 x Q [CaO2=13.6 mlO2/liter x Hb x SaO2] VO2= (CaO2- CvO2)x Q [PvO2=13.6 ml O2/liter xHbx SvO2] Fick Q = VO2/(CaO2-CvO2)

nl. 4-8 liters/min nl. 2.5-4.0 liters/min/ m2 nl. 800-1200 dynesxs/cm5 nl. < 250 dynesxs/cm5 nl. 500 ml O2/m2 BSA nl. 125ml O2/m2 BSA nl. 4-8 liters/min

Respiratory Mechanics

Compliance Respiratory System (Crs) = Vt ml/Pplat-PEEP Airway Resistance (Raw) = PiP-Pplat/ Flow (l/s)

nl. 75-100 ml/cm H2O nl. 3-5 cm H2O/l/s

Oxygenation

PaO2 predicted = 109-0.4(age) A-a gradient = PAO2-PaO2 PAO2 = {(760-47)x FiO2(0.21)}- PaCO2/0.8 PaO2/FiO2 = 476

nl. < 10 nl. 101 mm Hg < 300 = Acute Lung Injury, < 200 = ARDS

Weaning

PPaO2 Minute Ventilation (Ve) Vital Capacity (Vc) FEV1 Vt Negative Insp Force Maximum Voluntary Ventilation Rapid Shallow Breathing index f(b/min)/Vt (liters)

> 60 on FiO2 0.4 or less <10 liters/minute > 1 liter - nl. 75 cc/kg > 10 cc/kg - nl. 50-60 cc/kg >5 cc/kg - nl. 5 cc/kg < - 25 cm H20 - nl. - 75 cm H20 > 2 x Ve < 105 - nl. 20

Nutrition (basics)

Calories Protein Fat Ca PO4 Mg N2 Balance = (Protein intake (g)/ 6.25) - (UUN 24 hr/0.8) + 4 gms

25-35 kcal/kg/day - nl. 1800 kcal/day 1-2 gms/kg/day - nl. 50-100 gms 100 gms/week (up to 25 % in rare pts) 250 meq/day 40 mg/day 0.5 meq/ day

Renal

• FeNa= (Una x Pcr x100)/(Pna x Ucr)
• CrCl= (Ucr x U vol)/Pcr
• CrCl (est) = (140 - age)(wt. kgs)/(Pcr)72 [multiply by 0.85 for a woman]
• AG = Na -(Cl + HCO3), Delta Gap = 24 - AG (if delta gap + HCO3 > 24, complex acid/base problem)
• Metabolic Acidosis: pCO2 = [1.5 ( HCO3) + 8]+/- 2
• Respiratory acidosis: HCO3 rises 1meq for each 10 mmHg PaCO2
• [H+ ] = 24 x PaCO2/HCO3; [H+ ]= 40, pH = 7.40, [H+ ]= 50, pH = 7.3, [H+ ] = 30, pH = 7.5
• Posm = (Na x2) + BUN/2.8 + Gluc/18
• TBW = 0.6 x wt kgs

* Water deficit = current TBW x [ measured Na/140 meq/l] - 1
* Desired TBW =( measured Na x current TBW)/ 140 meq/l
* These calculations tell the deficit at one point in time. You need to correct the ongoing problem as well as correct the underlying deficit!