CANADIAN JOURNAL OF ANESTHESIA
CAN J ANESTH 55: 9 www.cja-jca.org September, 2008
Company, San Diego, CA, USA). Comparison of the
size 4 and 5 masks reveals that the cuffs are alike, and
equal in size to the accustomed measurements of the
size 4 LMA. The size 5 Supreme LMA does not have
the larger dimension cuff comparable to the size 5
PLMA. The only difference between the size 4 and
5 Supreme LMAs is the length of their bite blocks.
The size 5 Supreme differs by an approximate 2 cm
extension in length of the bite block. Our suggestion
to attach an extender for the size 4 PLMA in men
accomplishes this same effect.
Michael S. Stix md?phd
Cornelius J. O’Connor Jr md
Dennis R. Valade crna
Lahey Clinic, Burlington, USA
Accepted for publication June 18, 2008.
1 Brain AI, Verghese C, Strube PJ. The LMA ‘ProSeal”
– a laryngeal mask with an oesophageal vent.
Br J Anaesth 2000; 84: 650–4.
2 Stix MS, O’Connor CJ Jr. Maximum minute
ventilation test for the ProSeal laryngeal mask airway.
Anesth Analg 2002; 95: 1782–7.
3 Brimacombe J, Richardson C, Keller C, Donald S.
Mechanical closure of the vocal cords with the larynge-
al mask airway ProSeal. Br J Anaesth 2002; 88: 296–7.
4 Stix MS, O’Connor CJ Jr. Depth of insertion of the
ProSeal laryngeal mask airway. Br J Anaesth 2003; 90:
5 Brain AI, Verghese C. Correct fixation of the LMA
ProSeal. Anaesthesia 2003; 58: 922.
Spinal anesthesia for Cesarean delivery
in a patient with cerebral venous sinus
To the Editor:
We present a case of cerebral venous sinus thrombosis
(CVST), a rare complication in pregnancy, in a par-
turient whom we successfully managed via Cesarean
delivery under spinal anesthesia. In accordance with
institutional policy, we obtained consent to use the
Protected Health Information in this letter for research
and educational purposes.
A 22-yr-old gravida 4, para 2, at 36 weeks of pre-
gnancy, was admitted with intense frontal headache,
photophobia, and nausea. Noncontrast computed
tomography of the brain showed a prominent right
sagittal sinus. Magnetic resonance venography con-
firmed the diagnosis of CVST involving the supe-
rior sagittal, right transverse, and right sigmoid
sinuses extending into the right internal jugular vein
The patient’s neurological examination was nor-
mal, and she was treated with a heparin infusion. She
had several episodes of mild hypertension (peaks in
blood pressure to 140/80 mmHg) and bradycardia
(to a nadir of 40 beats·min–1). Coagulation studies
revealed an abnormally low functional protein S level
(40%); however, her protein C and antithrombin III
levels were within normal limits, and tests for factor V
Leiden, prothrombin G20210A mutation, and lupus
anticoagulant were negative.
At term, it was decided to manage the patient via
Cesarean delivery. After normalization of the activated
partial prothrombin time, spinal anesthesia consisting
of bupivacaine 10.5 mg 0.75% in 8.25% dextrose, fen-
tanyl 20 μg, and preservative-free morphine 150 μg
(total volume 2.1 mL) was administered through a
25G pencil-point spinal needle, with difficulty, due to
posterior lumbar edema. The anesthetic was almost
FIGURE Axial magnetic resonance venography confirming the
diagnosis of cerebral venous sinus thrombosis involving the supe-
rior sagittal, right transverse, and right sigmoid sinuses extending
into the right internal jugular vein.
correspondence? 659 Download full-text
CAN J ANESTH 55: 9 www.cja-jca.org September, 2008
immediately complicated by bradycardia (heart rate
values into the mid 30s), which responded to glyco-
pyrrolate 0.4 mg with a period of tachycardia (maxi-
mum heart rate of 140 beats·min–1) slowly normalizing
over the course of the procedure. A viable female with
Apgar scores of 9/9 was delivered. The patient was
discharged on postpartum day six with neurological
follow-up and warfarin anticoagulation.
Cerebral venous sinus thrombosis is a rare disorder
with an incidence of 3:1,000,000, and pregnancy,
being a recognized hypercoagulable state, is known
to increase the risk of CVST. The incidence increases
approximately 30-fold during the third trimester of
pregnancy and the immediate postpartum period.1,2
Specific blood coagulation disorders such as anti-
thrombin III deficiency, protein C, or protein S have
also been identified as a particularly important origin
of CVST; however, these tests must be carefully inter-
preted in pregnancy.3 Our patient’s finding of a low
functional protein S at 40% (normal range 60–115%)
can be a spurious one in pregnancy.4 It has been shown
that free protein S levels fall significantly between the
first and second trimester of normal pregnancy, with-
out significant change in function. Therefore, Faught
et al.5 suggest postponing protein S evaluation for
hypercoagulability until at least six weeks postpartum.
A majority of patients with CVST will show symptoms
of increased intracranial pressure; our patient was no
exception. In addition to headache and light sensitiv-
ity, she had several occurrences of slight hypertension
and bradycardia (Cushing’s reflex).
Although spinal anesthesia has been performed with-
out complications in similar situations, there is a risk
of decreased cerebral perfusion or aggravating brain
shifts. However, in this patient’s situation, we felt that
spinal anesthesia would confer a greater benefit than
risk. The patient was conscious for neurological evalu-
ation and for participation in the delivery. General
anesthesia carries the risk of further increasing intra-
cranial pressure by enhanced hemodynamic responses
at laryngoscopy. Positive pressure ventilation can also
decrease venous drainage from the cerebral vascula-
ture. Epidural analgesia was discounted; large volume
injections into the epidural space have been shown to
significantly increase intracranial pressure.
In conclusion, we present spinal anesthesia as a
successful, albeit controversial, alternative to general
anesthesia in this patient with CVST.
Richard C. Month md
Sonia J. Vaida md
Pennsylvania State University College of Medicine,
Penn State Hershey Medical Center, Hershey, USA
The authors have no commercial or non-commercial
interests that may be considered a conflict of interest
in this work.
Accepted for publication May 31, 2008.
1 Masuhr F, Mehraein S, Einhaupl K. Cerebral venous
and sinus thrombosis. J Neurol 2004; 251: 11–23.
2 Stam J. Thrombosis of the cerebral veins and sinuses.
N Engl J Med 2005; 352: 1791–8.
3 Holzman RS, Bessim S. Regional anesthesia for a
parturient with venous sinus thrombosis and placental
abruption undergoing fractional heparin therapy. Anes-
thesiology 2006; 105: 423–4.
4 Toglia MR, Weg JG. Venous thromboembolism during
pregnancy. N Engl J Med 1996; 335: 108–14.
5 Faught W, Garner P, Jones G, Ivey B. Changes in
protein C and protein S levels in normal pregnancy.
Am J Obstet Gynecol 1995; 172: 147–50.