Download Case 1: Craniofacial Resection with Rectus Free-Flap

Case Study
Fluid Management for Craniofacial
Resection with Rectus Free-Flap
D. John Doyle MD PhD FRCPC
Cleveland Clinic Foundation
[email protected]
March 2003
Case: Craniofacial Resection
with Rectus Free-Flap
A 76 year-old male, weighing 81 kg who was 185 cm tall, presented
with complaints of facial pain and swelling. The patient had smoked a
pack of cigarettes a day for almost 50 years. About 10 years ago, he
developed angina while playing tennis. The angina was treated with
the beta-blocker atenolol and the patient quit his smoking habit.
At the time of diagnosis, the patient reported that his infrequent angina
attacks responded quickly to sublingual nitroglycerine tablets. He
described his exercise tolerance as good, being able to climb three
flights of stairs before "getting pooped". The patient took no other
medications and had no allergies.
Remember
• 76 year-old male
• Former smoker
• CHD
• Complaints of facial pain and swelling
Diagnosis
A diagnosis of squamous cell carcinoma of
the maxillary sinus was made by
magnetic resonance imaging and confirmed
by biopsy following a workup.
Surgical Plan
SURGERY
The surgical plan was to undertake a 10-hour
craniofacial resection of the right maxilla and orbit
and to replace the defect with a rectus muscle freeflap using microvascular techniques. A three litre
blood loss is expected.
•
10-hour craniofacial resection
•
3 L expected blood loss
Preoperative Tests
Laboratory results included a hemoglobin
concentration of 13 g/dL, a creatinine of 1.1
mg/dL. Vital signs, serum electrolytes,
electrocardiogram and chest X-ray were all
unremarkable.
· Hb 13 g/dL
· Creatinine 1.1 mg/dL
Coronary Artery Disease
Although this patient appeared to be in fairly
good shape, with good exercise tolerance,
he had known coronary artery disease.
Because of his coronary artery disease, most
anesthesiologists would not allow his
hemoglobin to drop significantly below 10
g/L.
Blood Volume Estimate
Using 65 mL/kg as a blood volume
estimate, his blood volume (BV) was
calculated to be about 5300 mL.
ABL=2(5300) x (130-100)/(130+100)
=1400 mL (approx.)
This suggests that with appropriate fluid
replacement using crystalloid or colloid, the
patient could lose up to about 1400 mL of blood,
before a transfusion of packed red blood cells
would likely become necessary. If serial blood
samples were taken from an arterial line, it would
be possible to know exactly when a minimum
acceptable hemoglobin or hematocrit had been
reached.
ABL Formula
The allowable blood loss (ABL) was
estimated using the following formula:
ABL=2BV x (Starting Hb-Allowable
Hb)/(Starting Hb+Allowable Hb)
ABL=2(5300) x (130-100)/(130+100)
=1400 mL (approx.)
Two options to replace
ongoing blood losses
• 4:1 with a crystalloid such as
saline or Ringer’s lactate solution
or
• 1:1 with a colloid such as PENTASPAN®
(10% pentastarch in 0.9% sodium chloride
injection)
This is given in order to keep the patient
isovolemic.
Rule of Thumb
One often used "rule of thumb" is to replace
initial blood losses with crystalloid such as
saline on a 4:1 basis until blood losses reach
15-20% of blood volume. Replace
subsequent losses 1:1 with a colloid such as
PENTASPAN® (to keep patient isovolemic)
until the hemoglobin or hematocrit falls
below the "transfusion trigger".
Rule of thumb: Start Colloids at 15
- 20% Blood Volume Loss
Example (20% blood loss rule of thumb)
 77 kg man
 Blood volume estimated at 65 ml/kg x 77 kg = 5
liters
 20% blood volume = 1 liter of blood
 Crystalloid replacement for 1 liter blood is 3-4 liters
 Thus, consider starting a colloid after 3-4 liters of
crystalloid given to replace lost blood
Transfusion Trigger
In this case, a transfusion trigger of 10 g/dL
would be used because of the
patient's cardiopulmonary disease. In a
much younger patient without any
known cardiopulmonary disease, the trigger
level might be set at 8 or even 7 g/L,
depending on clinical judgement.
Remember
• ABL 1400 mL
• 4 L of crystalloid replaces 1 L of blood loss
• Further blood loss replaced with
PENTASPAN®
• Transfusion trigger 10 g/L
Preoperative Fluid Deficits
Preoperative fluid deficits are often estimated
using the 4-2-1 rule. For an 81 kg patient this
amounts to about 130 mL/hr. Assuming that the
patient has been NPO for about 10 hours
preoperatively and has had no IV prior to
going to the OR, the preoperative fluid deficit
would be about 130 mL/hr x 10 hrs = 1300 mL.
Many anesthesiologists attempt to replace this
deficit over about a two hour span at the beginning
of the case.
4-2-1 Rule
• 4 ml/kg/hr for first 10 kg
• 2 ml/kg/hr for next 10 kg
• 1 ml/kg/hr thereafter
EXAMPLES
10 kg
20 kg
30 kg
40 kg
70 kg
40 ml/hr
60 ml/hr
70 ml/hr
80 ml/hr
120 ml/hr
Maintenance Fluid Requirements
Maintenance fluid requirements would
amount to about 130 mL/hr
Third Space Losses
Third space losses include both evaporative
losses from surgical area and fluid that
enters the interstitium as a result of tissue
trauma. For a case such as this one, a
reasonable estimate of the third space losses
would be about 4 mL/kg/hr or about 320
mL/hr.
Remember
• Preoperative fluid deficit anticipated at
1300 mL
• Third space losses of 320 mL/hr expected
• Maintenance fluid requirements of
130mL/hr expected
Desired Fluid Therapy 1
Run the IV at 450 mL/hour (130 mL/hr
maintenance + 320 mL/hr third space loss
replacement) throughout course of treatment.
In addition, for the first two hours add 650 mL/hr
to the above amount to replace the 1300 mL
deficit over 2 hours. The infusion rate will then be
1100 mL/hr (=450 mL/hr + 650 mL/hr) for the
first two hours.
Desired Fluid Therapy 2
Switch predominately to PENTASPAN® 1:1 to
replace the ABL of 1400 mL, with use of
crystalloids as judged clinically appropriate by
anesthesiologist.
Transfuse packed cells when hemoglobin falls
below the "transfusion trigger" of 10 g/dL.
Remember
• Run IV at 450 mL/hr. throughout treatment
course to replace intra-op fluid losses
• Add 650 mL/hr over first two hours to replace preop deficit
• Add PENTASPAN® to replace ABL of 1400 mL
• Transfuse with packed cells when transfusion
trigger of 10 g/dL of hemoglobin is reached
Final Note
Note: These are starting points only. Most
anesthesiologists would insert a CVP line,
an arterial line and a Foley catheter in this
patient to further guide fluid therapy. Fluid
delivery may have to be increased should
oliguria or hypotension occur.
The End