Perfusion. 2006 Dec;21(5):247-53. 

Comparison of two different extracorporeal circuits on cerebral embolization
during cardiopulmonary bypass in children.

Rodriguez RA, Belway D.

Department of Surgery, Division of Cardiac Surgery, University of Ottawa Heart
Institute, Ontario, Canada. rrodriguez@ottawaheart.ca

OBJECTIVE: To compare the effect of two different extracorporeal circuits on the
counts of high-intensity transient signals (HITS) during pediatric
cardiopulmonary bypass (CPB). METHODS: Transcranial Doppler was used to detect
HITS associated with extracorporeal sources during the period of aortic
crossclamping in the middle cerebral artery of children undergoing CPB. Based on
body size, children were assigned one of two extracorporeal circuits (A or B).
Circuit A included a D-705 oxygenator and associated reservoir, and circuit B
included a Lilliput oxygenator and reservoir. Patients were further classified
into two groups according to the complexity of surgical repair: single simple
lesions or multiple complex lesions. RESULTS: We studied 109 pediatric patients.
Surgery for multiple complex lesions was associated with longer periods of
aortic crossclamping and CPB (p < 0.0001). The median count of extracorporeal
HITS was 12 (25th, 75th percentiles: 3, 51). The type of extracorporeal circuit
(p = 0.012) and the complexity of surgical repair (p < 0.0001) had an effect on
the HITS counts. The use of circuit A was associated with higher HITS counts
during surgery for multiple complex lesions compared to single simple lesions (p
< 0.0001). Conversely, no differences were found with the use of circuit B
between these two surgical groups (p > 0.25). During surgery for multiple
complex lesions, patients treated with circuit A showed higher HITS counts than
those with circuit B (p < 0.01), but there were no circuit-related differences
in HITS counts (p = 0.30) during single simple lesions. CONCLUSION: Variations
in the design characteristics of extracorporeal circuits can increase cerebral
emboli during CPB in children. This may be related to the reduced ability of
some circuits to remove emboli during long periods of CPB for complex congenital
heart-surgery.

Eur J Cardiothorac Surg. 2006 Dec 22; [Epub ahead of print] 

Pretreatment with aminophylline reduces release of Troponin I and neutrophil
activation in the myocardium of patients undergoing cardioplegic arrest.

Luo WJ, Qian JF, Jiang HH.

Department of Cardiothoracic Surgery, Xiang Ya Hospital, Central South
University, Changsha, Hunan, PR China.

Objective: Cardioplegic arrest and subsequent reperfusion results in myocardial
injury partly related to local inflammation in the heart. It has been proven
that aminophylline has numerous anti-inflammatory effects. This study has been
designed to evaluate the effects of aminophylline used as a cardioprotective
agent for patients undergoing cardiopulmonary bypass (CPB) for valve
replacement. Methods: Thirty patients undergoing elective valve replacement were
randomized to receive either aminophylline (n=15), or normal saline (control
n=15). Administration of aminophylline (5mg/kg) was injected intravenously after
induction of anesthesia. The cardiac Troponin I (cTnI), myocardial
myeloperoxidase (MPO) activity, atrial cyclic AMP, and a coronary sinus
neutrophil count were measured before and after cardioplegic arrest. Results:
There were no differences between the two groups with regard to clinical
variables. The cTnI concentration increased significantly after aortic
declamping in both groups. However, it was significantly lower, 8h after aortic
declamping, in aminophylline group (1.00+/-0.41 vs 2.37+/-1.35ng/ml p=0.038).
The atrial cAMP was significantly higher before aortic cross-clamping in
aminophylline group (42.5+/-6.7pmol/g tissue vs 30.6+/-12.4pmol/g tissue
p=0.04). In addition, we found that the aminophylline group had a significantly
lower MPO after reperfusion (1.50+/-0.58U/g tissue vs 0.86+/-0.24U/g tissue
p=0.003), and a significantly lower neutrophil count 30min after aortic
declamping (0.68+/-0.11x10(3) cell/ml vs 0.32+/-0.16x10(3) cell/ml, p=0.023).
Conclusions: Pretreatment with intravenous aminophylline reduces the subclinical
myocardial injury and neutrophil activation in patients undergoing CPB for valve
replacement.

Eur J Cardiothorac Surg. 2006 Dec 14; [Epub ahead of print] 

The effect of sodium nitroprusside infusion on renal function during reperfusion
period in patients undergoing coronary artery bypass grafting: a prospective
randomized clinical trial.

Kaya K, Oguz M, Akar AR, Durdu S, Aslan A, Erturk S, Tasoz R, Ozyurda U.

Division of Cardiovascular Surgery, Umut Heart Hospital, Ankara, Turkey.

Objective: Acute renal failure remains a common and serious complication of
cardiac surgery. In this randomized trial, we aimed to assess whether sodium
nitroprusside (SNP) infusion during cardiopulmonary bypass (CPB) could prevent
renal dysfunction after coronary artery bypass grafting (CABG) surgery. Methods:
Between October 2004 and May 2006, 240 consecutive patients with stable angina
undergoing elective CABG for multi-vessel coronary artery disease were
prospectively randomized into control (n=116, 72 men, mean age 61.3+/-9.7 years)
or SNP groups (n=124, 81 men, 60.8+/-10.8 years). SNP group received SNP after
initiation of rewarming period during CPB at a dose of 0.1mg/kg/h and the
infusion was concluded by weaning from CPB. The anesthetic and CPB regimes were
standardized. Blood urea nitrogen (BUN), serum creatinine (SCr), estimated
glomerular filtration rate (eGFR), creatinine clearance (C(Cr)), urine output,
serum cardiac specific troponin I (cTnI), creatine kinase cardiac isoenzyme
(CKMB), and CPK were measured preoperatively and daily until day 5 after
surgery. Results: There were no differences in baseline levels of BUN, SCr,
eGFR, C(Cr), cTnI, CKMB, CPK levels and EuroSCORES between the groups. Although
the durations of cross clamp, CPB times, and postoperative cardiac enzymes were
similar in both groups; in the control group, there was a significantly lower
urine excretion during CPB (p=0.002) and the operation (p=0.041). Peak
postoperative SCr levels were significantly (p=0.001) lower in the SNP group
than in the control group (1.29+/-0.28 vs 1.42+/-0.34mg/dl). The incidence of
>/=50%DeltaSCr was significantly higher in the control group when compared with
the SNP group (35.3 vs 13.7%, p<0.001). Development of new C(Cr) less than
50ml/min postoperatively was significantly higher in the control group compared
with the SNP group (14 vs 38%, p<0.001). Conclusion: SNP administration during
rewarming period of non-pulsatile CPB in patients undergoing CABG surgery is
associated with improved renal function compared with conventional medical
treatment providing adequate preload and mean arterial pressures.

Ann Fr Anesth Reanim. 2006 Nov-Dec;25(11-12):1144-8. 

[Thrombosis of a cardiopulmonary bypass circuit despite recommended
hypocoagulation with danaparoid during the acute phase of type II
heparin-induced thrombocytopenia]

[Article in French]

Salmi L, Elalamy I, Leroy-Matheron C, Houel R, Thebert D, Duvaldestin P.

Service d'anesthesie-reanimation, CHU Henri-Mondor, 51, avenue du
Marechal-de-Lattre-de-Tassigny, 94010 Creteil, France. zergbh@noos.fr


A 36-year-old patient was admitted to our hospital with ischaemic stroke. The
initial assessment allowed the diagnosis of an antiphospholipid syndrome (APS)
and an intracardiac mass suggestive of a heart tumour. The patient was treated
with unfractionated heparin. Type II heparin-induced thrombopenia (HIT) was
diagnosed on the 18th day of therapy. Given the risk of stroke recurrence it was
decided to remove the cardiac tumour surgically. Cardiopulmonary bypass (CPB)
was performed using danaparoid in a state of deep hypothermia, in accordance
with the well-established protocol in use in our department. As the CPB and
surgical procedure came to an end a massive thrombus began forming in the
circuit, requiring immediate displacement of the CPB cannulae. The anti-Xa
activity level obtained had been considered effective at an estimated 1.20
IU/ml, although, the level recommended by Magnani is between 1.50 and 2.0 IU/ml.
There was no clinical consequence and postoperative recovery was uneventful. The
discrepancy between the satisfactory level of anti-Xa activity and the thrombus
formation in the CPB circuit raises the issue of the diversity of published
anticoagulation protocols, the difficulty to extrapolate within a surgical team,
the need for intensive laboratory monitoring within a narrow therapeutic range,
as well as the patient profiles variability with concurrent disorders
complicating their clinical management.

J Artif Organs. 2006;9(4):214-9. Epub 2006 Dec 21. 

Heparin reduction with the use of cardiotomy suction is associated with
hyperfibrinolysis during distal aortic perfusion with a heparin-coated
semi-closed cardiopulmonary bypass system.

Shiiya N, Matsuzaki K, Kunihara T, Sugiki H.

Department of Cardiovascular Surgery, Hokkaido University Hospital, N14W5,
Sapporo 060-8648, Japan. shiyanor@med.hokudai.ac.jp

We sought to elucidate the effects of different anticoagulation levels and the
use of cardiotomy suction on the postoperative coagulatory and fibrinolytic
systems in patients undergoing distal aortic perfusion using a fully
heparin-coated (semi-)closed cardiopulmonary bypass (CPB) system incorporating a
soft reservoir bag. Thirty-two patients were divided into two groups: those who
underwent cardiotomy suction (S group, 18 patients) and those who did not (N
group, 14 patients). We administered 1-2 mg/kg heparin in the S group, which
achieved an activated clotting time (ACT) of 345 +/- 71 s. In the N group, we
administered 0.7-1 mg/kg heparin, which achieved an ACT of 297 +/- 52 s. Data on
platelet counts and serum levels of fibrinogen, antithrombin III, D-dimer, and
fibrin degradation products (FDP) were collected, and factors influencing these
variables were analyzed by multiple regression analysis. Both the patient group
and the initial ACT level were independent factors influencing postoperative
levels of FDP and D-dimer, whereas peak ACT level and the use of selective
visceral/renal shunt/perfusion, but not the patient group, were independent
factors influencing the postoperative platelet counts. In the S group, a
significant inverse correlation was found between the ACT and levels of FDP or
D-dimer, whereas no correlation was found in the N group. The use of cardiotomy
suction was associated with elevated FDP and D-dimer levels even when a fully
heparin-coated semi-closed CPB system was used. Lower ACT levels with the use of
cardiotomy suction were associated with higher FDP and D-dimer levels, whereas
such a relationship did not exist when cardiotomy suction was not used.

J Cardiothorac Vasc Anesth. 2006 Dec;20(6):819-25. Epub 2006 Jan 6. 

Correlation between cerebral and mixed venous oxygen saturation during moderate
versus tepid hypothermic hemodiluted cardiopulmonary bypass.

Baraka A, Naufal M, El-Khatib M.

Department of Anesthesiology, School of Medicine, American University of Beirut,
Beirut, Lebanon.

Objective: This study was undertaken to compare cerebral oxygen saturation
(RsO(2)) and mixed venous oxygen saturation (SvO(2)) in patients undergoing
moderate and tepid hypothermic hemodiluted cardiopulmonary bypass (CPB). Design:
Prospective study. Settings: University hospital operating room. Participants:
Fourteen patients undergoing elective coronary artery bypass graft surgery using
hypothermic hemodiluted CPB. Interventions: During moderate (28 degrees -30
degrees C) and tepid hypothermic (33 degrees -34 degrees C) hemodiluted CPB,
RsO(2) and SvO(2) were continuously monitored with a cerebral oximeter via a
surface electrode placed on the patient's forehead and with the mixed venous
oximeter integrated in the CPB machine, respectively. Measurements and Main
Results: Mean +/- standard deviation of RsO(2), SvO(2), PaCO(2), and hematocrit
were determined prebypass and during moderate and tepid hypothermic phases of
CPB while maintaining pump flow at 2.4 L/min/m(2) and mean arterial pressure in
the 60- to 70-mmHg range. Compared with a prebypass value of 76.0% +/- 9.6%,
RsO(2) was significantly decreased during moderate hypothermia to 58.9% +/- 6.4%
and increased to 66.4% +/- 6.7% after slow rewarming to tepid hypothermia. In
contrast, compared with a prebypass value of 78.6% +/- 3.3%, SvO(2)
significantly increased to 84.9% +/- 3.6% during moderate hypothermia and
decreased to 74.1% +/- 5.6% during tepid hypothermia. During moderate
hypothermia, there was poor agreement between RsO(2) and SvO(2) with a gradient
of 26%; however, during tepid hypothermia, there was a strong agreement between
RsO(2) and SvO(2) with a gradient of 6%. The temperature-uncorrected PaCO(2) was
maintained at the normocapnic level throughout the study, whereas the
temperature-corrected PaCO(2) was significantly lower during the moderate
hypothermic phase (26.8 +/- 3.1 mmHg) compared with the tepid hypothermic phase
(38.9 +/- 3.7 mmHg) of CPB. There was a significant and positive correlation
between RsO(2) and temperature-corrected PaCO(2) during hypothermia.
Conclusions: During moderate hypothermic hemodiluted CPB, there was a
significant increase of SvO(2) associated with a paradoxic decrease of RsO(2)
that was attributed to the low temperature-corrected PaCO(2) values. During
tepid CPB after slow rewarming, regional cerebral oxygen saturation was
increased in association with an increase with the temperature-corrected PaCO(2)
values. The results show that during hypothermic hemodiluted CPB using the
alpha-stat strategy for carbon dioxide homeostasis, cerebral oxygen saturation
is significantly higher during tepid than moderate hypothermia.

Ann Thorac Surg. 2006 Dec;82(6):2233-9. 

Moderately hypothermic cardiopulmonary bypass and low-flow antegrade selective
cerebral perfusion for neonatal aortic arch surgery.

Oppido G, Napoleone CP, Turci S, Davies B, Frascaroli G, Martin-Suarez S,
Giardini A, Gargiulo G.

Pediatric Cardiac Surgery Unit, S. Orsola-Malpighi Hospital, University of
Bologna Medical School, Bologna, Italy. guidooppido@yahoo.com

BACKGROUND: Although deep hypothermic circulatory arrest has been extensively
used in neonates for aortic arch surgery, the brain and other organs might be
adversely affected by prolonged ischemia and deep hypothermia. METHODS: Between
December 1997 and January 2005, 70 consecutive neonates underwent Norwood stage
I procedure for hypoplastic left heart syndrome (group A, n = 30), or aortic
arch repair for interruption or coarctation with arch hypoplasia (group B, n =
40), with antegrade selective cerebral perfusion (ASCP). Mean weights were 3.0
+/- 0.2 kg and 2.8 +/- 0.07 kg, and mean ages were 10 +/- 3.5 days and 14 +/-
10.6 days in groups A and B, respectively. Only 2 patients were older than 30
days. Core body temperature was lowered to 25 degrees C, and mean pump flow
during ASCP was initiated at 10 to 20 mL/(kg x min) and adjusted to guarantee a
radial/temporal artery pressure of 30 to 40 mm Hg and venous oxygen saturation
of more than 70%. Hematocrit was maintained at 30%. RESULTS: Early mortality was
17% (group A, 23%; group B, 12.5%; p = 0.19). Six late deaths occurred (3 in
each group), and at 36 months, Kaplan-Meier overall survival was 64% +/- 9.2% in
group A and 85% +/- 5.7% in group B. One patient had postoperative seizures.
Age, weight, sex, prematurity, group A, and ASCP duration did not influence
early mortality. CONCLUSIONS: Antegrade selective cerebral perfusion is a safe
and effective procedure and might improve outcome of neonatal aortic arch
surgery, minimizing neurologic impact without the need for deep hypothermia.

Crit Care. 2006 Nov 24;10(6):R165 [Epub ahead of print] 

Children undergoing cardiac surgery for complex cardiac defects show imbalance
between pro- and anti-thrombotic activity.

Heying R, van Oeveren W, Wilhelm S, Schumacher K, Grabitz RG, Messmer BJ,
Seghaye MC.

Department of Pediatric Cardiology, University Hospital, RWTH-Aachen,
Pauwelsstrasse 30, 52074 Aachen, Germany. heying@uni-duesseldorf.de.

ABSTRACT: INTRODUCTION: Cardiac surgery with cardiopulmonary bypass (CPB) is
associated with the activation of inflammatory mediators that possess
prothrombotic activity and could cause postoperative haemostatic disorders. This
study was conducted to investigate the effect of cardiac surgery on
prothrombotic activity in children undergoing cardiac surgery for complex
cardiac defects. METHODS: Eighteen children (ages 3 to 163 months) undergoing
univentricular palliation with total cavopulmonary connection (TCPC) (n = 10) or
a biventricular repair (n = 8) for complex cardiac defects were studied.
Prothrombotic activity was evaluated by measuring plasma levels of prothrombin
fragment 1+2 (F1+2), thromboxane B2 (TxB2), and monocyte chemoattractant
protein-1 (MCP-1). Anti-thrombotic activity was evaluated by measuring levels of
tissue factor pathway inhibitor (TFPI) before, during, and after cardiac
surgery. RESULTS: In all patients, cardiac surgery was associated with a
significant but transient increase of F1+2, TxB2, TFPI, and MCP-1. Maximal
values of F1+2, TxB2, and MCP-1 were found at the end of CPB. In contrast,
maximal levels of TFPI were observed at the beginning of CPB. Concentrations of
F1+2 at the end of CPB correlated negatively with the minimal oesophageal
temperature during CPB. Markers of prothrombotic activity returned to
preoperative values from the first postoperative day on. Early postoperative
TFPI levels were significantly lower and TxB2 levels significantly higher in
patients with TCPC than in those with biventricular repair. Thromboembolic
events were not observed. CONCLUSION: Our data suggest that children with
complex cardiac defects undergoing cardiac surgery show profound but transient
imbalance between pro- and anti-thrombotic activity, which could lead to
thromboembolic complications. These alterations are more important after TCPC
than after biventricular repair but seem to be determined mainly by low
antithrombin III.

Anesthesiology. 2006 Dec;105(6):1117-21. 

Estimation of mean body temperature from mean skin and core temperature.

Lenhardt R, Sessler DI.

Outcomes Research Institute, Department of Anesthesiology & Perioperative
Medicine, Neurosciences Intensive Care Unit, University of Louisville,
Louisville, Kentucky 40202, USA. rainer.lenhardt@louisville.edu

BACKGROUND: Mean body temperature (MBT) is the mass-weighted average temperature
of body tissues. Core temperature is easy to measure, but direct measurement of
peripheral tissue temperature is painful and risky and requires complex
calculations. Alternatively MBT can be estimated from core and mean skin
temperatures with a formula proposed by Burton in 1935: MBT = 0.64 x TCore +
0.36 x TSkin. This formula remains widely used, but has not been validated in
the perioperative period and seems unlikely to remain accurate in dynamic
perioperative conditions such as cardiopulmonary bypass. Therefore, the authors
tested the hypothesis that MBT, as estimated with Burton's formula, poorly
estimates measured MBT at a temperature range between 18 degrees and 36.5
degrees C. METHODS: The authors reevaluated four of their previously published
studies in which core and mass-weighted mean peripheral tissue temperatures were
measured in patients undergoing substantial thermal perturbations. Peripheral
compartment temperatures were estimated using fourth-order regression and
integration over volume from 18 intramuscular needle thermocouples, 9 skin
temperatures, and "deep" hand and foot temperature. MBT was determined from
mass-weighted average of core and peripheral tissue temperatures and estimated
from core temperature and mean skin temperature (15 area-weighted sites) using
Burton's formula. RESULTS: Nine hundred thirteen data pairs from 44 study
subjects were included in the analysis. Measured MBT ranged from 18 degrees to
36.5 degrees C. There was a remarkably good relation between measured and
estimated MBT: MBTmeasured = 0.94 x MBTestimated + 2.15, r = 0.98. Differences
between the estimated and measured values averaged -0.09 degrees +/- 0.42
degrees C. CONCLUSIONS: The authors concluded that estimation of MBT from mean
skin and core temperatures is generally accurate and precise.

Paediatr Anaesth. 2006 Dec;16(12):1297. 

Evidence of cortisol suppression in neonates after major cardiac surgery: is
supplementation necessary?

Murphy TW, Homewood J, McCabe A, Humphreys N, Wolf AR.

Department of Paediatric Anaesthesia and Intensive Care, Bristol Royal Hospital
for Children, Bristol, UK.

Introduction: Infants and children undergoing major cardiac surgery mount a
substantial stress response. Data from a previous investigation suggested that
after cardiac surgery infants under 90 days had prolonged suppression of
cortisol production (1) that might not be explained as simply due to the use of
dexamethasone (used routinely for cardiopulmonary bypass). This study was
designed to determine the origins of this suppressed cortisol response. Methods:
Local ethics committee approval was granted for the study. Ten neonates due to
undergo cardiac surgery using cardiopulmonary bypass were recruited after
informed parental consent. A standard anaesthetic technique was used. Baseline
blood samples were taken following induction of anaesthesia and arterial line
insertion: a dose of dexamethasone (0.5 mg.kg(-1)) was then administered as per
usual protocol. Blood was taken at release of the cross clamp (ROCC) and then 2,
6, 24, 48 and 72 h later. Blood was not taken at 72 h if the patient no longer
had invasive monitoring lines in place. At each time point concentrations of
cortisol, adrenocorticotrophic hormone (ACTH) and dexamethasone were measured.
Results: Time ACTH (ng.l(-1)) Cortisol (nmol.l(-1))Dexamethasone
(nmol.l(-1))Baseline68.7 (38.6-123.0)647.0 (510.0-1038)0.8 (0.8-1.0)ROCC18.3
(11.3-28.7)439.0 (340.0-556.0)173.5 (153.3-186)ROCC + 211.2 (9.0-14.9)201.0
(134.0-416.0)147.8 (114.6-176)ROCC + 69.0 (9.0-10.4)87.5 (49.0-94.0)60.0
(50.6-103.3)ROCC + 249.0 (9.0-13.8)98.0 (29.0-244.0)5.1 (2.4-12.6)ROCC + 4812.6
(9.0-16.4)302.0 (173.0-451.0)1.3 (1-3.9)ROCC + 7212.4 (9.0-26.3)494.0
(176.0-686.0)1.7 (1-2.3)Note: Figures above are given as median (interquartile
range) for the 10 patients in the study. Statistical analysis was performed
after the data had been natural-log transformed. Plasma cortisol concentrations
reached a nadir 6 h post-ROCC. At 24 h post-ROCC cortisol was significantly
below baseline (P < 0.05), and was undetectable in four patients (<30
nmol.l(-1)). 48 h post-ROCC; eight out of 10 patients still had a cortisol level
below baseline. Plasma ACTH concentrations were also suppressed up to 48 h
post-ROCC (P < 0.05). However, plasma dexamethasone concentrations had returned
to background (baseline) values by 48 h post-ROCC, and therefore were unlikely
to still exert pharmacological effects. Furthermore, there was no significant
correlation between plasma dexamethasone and cortisol concentrations at either
24 or 48 h post-ROCC. Discussion: The data suggest that between 24 and 48 h
post-ROCC the patients could be at risk of relative adrenocortical insufficiency
as dexamethasone had been substantially cleared from the plasma and cortisol
continued to remain below baseline in the majority of patients. The independence
of dexamethasone and cortisol concentrations between 24 and 48 h is interesting
and would indicate that other regulators are responsible for the prolonged
pituitary adrenocortical suppression. Conclusions: Neonates may be at risk of
prolonged reduced cortisol secretion after major cardiac surgery via suppression
of pituitary ACTH release. The results cannot be dismissed as simple feedback
inhibition by prolonged elimination of dexamethasone. Neonates may benefit from
supplemental corticosteroids after major cardiac surgery by measurement of
plasma cortisol concentrations postoperatively and providing steroid
supplementation if required. Acknowledgements: We are grateful to the APA for
funding this study, to the biochemistry laboratory at Guy's and St Thomas' Trust
for performing the assays, and to the parents of the patients for allowing them
to be included in this study. Reference 1 Humphreys N et al.'Plasma cortisol
concentrations in children in PICU after cardiac surgery: evidence of prolonged
suppression in infants under 90 days old'. Abstract presented at PICS ASM,
September 2003.