High risk of intraoperative awareness during cardiopulmonary bypass with                 isoflurane administration via diffusion membrane oxygenators

In cardiac surgery with the aid of extracorporeal circulation (ECC), inhalation anaesthetics can be administered via the oxygenator. Until the recent advent of a new type of diffusion membrane oxygenator, we routinely added the inhalation agent, isoflurane, to the gas flow of a micro-porous capillary membrane-type oxygenator. Applying this procedure to the diffusion-type oxygenators, the depth of anaesthesia appeared to be affected, which manifested itself through unusually high intraoperative perfusion pressures. This observation led to a prospective randomized study comprising 60 patients and two models of a microporous capillary membrane oxygenator, as well as two models of a diffusion membrane oxygenator. Simultaneous isoflurane concentration measurements at both the gas inlet and outlet ports of the oxygenators showed that, whereas in the microporous capillary-type oxygenators the isoflurane administered was reduced by about 50% during the passage of gas through the device, there was only a minimal transfer of isoflurane in the diffusion-type membrane oxygenators.

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A pilot study comparing two polymethylpentene extracorporeal membrane oxygenators

Perfusion ◽

10.1177/0267659112457970 ◽

2012 ◽

Vol 28 (1) ◽

pp. 14-20 ◽

Cited By ~ 9

Author(s):

J Rambaud ◽

J Guilbert ◽

I Guellec ◽

S Renolleau

Keyword(s):

Pilot Study ◽

Oxygen Transfer ◽

Gas Flow ◽

Comparison Study ◽

Blood Products ◽

Membrane Oxygenator ◽

Removal Capacity ◽

Membrane Oxygenators ◽

Similar Cost ◽

Initial Results

Objective: We compared two polymethylpentene oxygenators being used in our unit: the Maquet Quadrox-iD paediatric® and the Medos Hilite 800LT®. Study design: A mono-centric, prospective pilot study was conducted on ten consecutive newborn patients who had been admitted to our hospital service for extracorporeal circulation (EC) treatment. We examined the rate of oxygen transfer, the CO2 removal capacity and the average sweep gas flow required to produce this result. We also assessed the disturbances of haemostasis, the need for labile blood products and the membrane oxygenator lifetime and cost of use. Conclusions: According to our study, it seems to us that Medos Hilite 800LT® membrane oxygenators demonstrate greater oxygen transfer and CO2 removal capacity than Maquet Quadrox-iD paediatric® membrane oxygenators, at a similar cost. These results lead us to conclude that it is reasonable to continue using Medos Hilite 800LT® membrane oxygenators. A broader comparison study would be necessary in order to support these initial results.

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Modelling lung and tissue diffusion using a membrane oxygenator circuit

Perfusion ◽

10.1177/0267659107083240 ◽

2007 ◽

Vol 22 (4) ◽

pp. 231-238 ◽

Cited By ~ 2

Author(s):

H. Dunningham ◽

C. Borland ◽

F. Bottrill ◽

A. Vuylsteke ◽

D. Gordon

Keyword(s):

Blood Flow ◽

Simple Model ◽

Linear Relationship ◽

Gas Flow ◽

Reference Ranges ◽

Membrane Oxygenator ◽

Model Lung ◽

Membrane Oxygenators ◽

Tissue Diffusion

A simple model lung has been designed using a membrane oxygenator circuit comprising two membrane oxygenators primed with one to two litres of equine blood, giving reproducible results over several hours. Normoxia and normocapnia were achieved consistently over the duration of the test with a blood flow of 2.5 l/min, oxygenator ventilation gas flow of 5 l/min air with 0.3 l/min O2 and deoxygenator ventilation gas flow of 5 l/min 5% CO2 in N2 with 0.2 l/min CO 2. The measured PaO2 was 81.3 (SD 3.35 mmHg), PvO2 38.3 (SD 1.38 mmHg), PvCO2 60.6 (SD 1.13 mmHg) and PaCO2 36.1 (SD 0.69 mmHg). MO2 and MCO2 were 116 ml/min and 169 ml/min, respectively. An increasing linear relationship was observed for FiO2 and the corresponding PaO2 and, similarly, with FiCO2 and PvCO2, providing reference ranges for this model. Perfusion (2007) 22, 231—238.

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In Vivo Uptake and Elimination of Isoflurane by Different Membrane Oxygenators during Cardiopulmonary Bypass

Anesthesiology ◽

10.1097/00000542-200207000-00019 ◽

2002 ◽

Vol 97 (1) ◽

pp. 133-138 ◽

Cited By ~ 56

Author(s):

Christoph Wiesenack ◽

Gunther Wiesner ◽

Cornelius Keyl ◽

Michael Gruber ◽

Alois Philipp ◽

...

Keyword(s):

Cardiopulmonary Bypass ◽

Blood Concentration ◽

Gas Flow ◽

Membrane Oxygenator ◽

Volatile Agent ◽

Blood Concentrations ◽

Isoflurane Concentration ◽

Membrane Oxygenators ◽

In Vivo Uptake

Background Volatile anesthetics are frequently used during cardiopulmonary bypass (CPB) to maintain anesthesia. Uptake and elimination of the volatile agent are dependent on the composition of the oxygenator. This study was designed to evaluate whether the in vivo uptake and elimination of isoflurane differs between microporous membrane oxygenators containing a conventional polypropylene (PPL) membrane and oxygenators with a new poly-(4-methyl-1-pentene) (PMP) membrane measuring isoflurane concentrations in blood. Methods Twenty-four patients undergoing elective coronary bypass surgery with the aid of CPB were randomly allocated to one of four groups, using either one of two different PPL-membrane oxygenators for CPB or one of two different PMP-membrane oxygenators. During hypothermic CPB, 1% isoflurane in an oxygen-air mixture was added to the oxygenator gas inflow line (gas flow, 3 l/min) for 15 min. Isoflurane concentration was measured in blood and in exhaust gas at the outflow port of the oxygenator. Between-group comparisons were performed for the area under the curve (AUC) during uptake and elimination of the isoflurane blood concentrations, the maximum isoflurane blood concentration (C(max)), and the exhausted isoflurane concentration (F(E)). Results The uptake of isoflurane, expressed as AUC of isoflurane blood concentration and a function of F(E), was significantly reduced in PMP oxygenators compared to PPL oxygenators (P < 0.01). C(max) was between 8.5 and 13 times lower in the PMP-membrane oxygenator groups compared to the conventional PPL-membrane oxygenator groups (P < 0.01). Conclusions The uptake of isoflurane into blood via PMP oxygenators during CPB is severely limited. This should be taken into consideration in cases using such devices.

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Blood compatibility of two different types of membrane oxygenator during cardiopulmonary bypass in infants

The International Journal of Artificial Organs ◽

10.1177/039139889401701006 ◽

1994 ◽

Vol 17 (10) ◽

pp. 543-548 ◽

Cited By ~ 10

Author(s):

Y.J. Gu ◽

P.W. Boonstra ◽

C. Akkerman ◽

H. Mungroop ◽

I. Tigchelaar ◽

...

Keyword(s):

Cardiopulmonary Bypass ◽

Blood Compatibility ◽

Hollow Fibre ◽

Membrane Oxygenator ◽

Hollow Fibre Membrane ◽

Flat Sheet ◽

Fibre Membrane ◽

Membrane Oxygenators ◽

Flat Sheet Membrane ◽

Sheet Membrane

The contact of blood with the artificial extracorporeal circuit causes a systemic inflammatory response due to blood activation. In this study, we compared two different paediatric membrane oxygenators used for extracorporeal circulation: a hollow fibre membrane oxygenator (Dideco Masterflo D-701, n=10), and a flat sheet silicone membrane oxygenator (Avecor Kolobow 800-2A, n=10). Blood compatibility was indicated by measuring complement activation as well as leukocyte and platelet activation. In patients perfused with a flat sheet membrane oxygenator, concentrations of complement split products C3a were significantly increased 30 minutes after the start of bypass (p<0.01), whereas only a mild increase of C3a was found in patients perfused with a hollow fibre membrane oxygenator. Leukocyte and platelet counts dropped uniformly in both groups after the start of bypass mainly due to hemodilution. Activation of leukocytes and platelets identified by both plasma β-glucuronidase and β-thromboglobulin was similar in both groups. Infants perfused with a flat sheet membrane oxygenator received significantly more donor blood than those perfused with a hollow fibre oxygenator (p<0.05). These results indicate that when used during paediatric cardiopulmonary bypass, a flat sheet membrane oxygenator has a higher complement activity than a hollow fibre membrane oxygenator, which is probably due to the relatively larger blood-surface contacting area of the oxygenator.

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A Prospective Study of Single Breath Vital Capacity Inhalation Induction with High Concentration of Sevoflurane (Sbvc-Hc) for LMA Insertion in Adults for Short Surgical Cases

Academia Anesthesiologica International ◽

10.21276/aan.2020.5.1.6 ◽

2020 ◽

Vol 5 (1) ◽

pp. 30-33

Author(s):

Kailash Prabhudev ◽

Naveen Kumar K

Keyword(s):

Prospective Study ◽

Short Duration ◽

Gas Flow ◽

Vital Capacity ◽

Randomized Study ◽

High Concentration ◽

Inhalation Induction ◽

Inhalation Anesthesia ◽

Volatile Anesthetic Agent ◽

The Mean

Background: Sevoflurane is a new volatile anesthetic agent with rapid induction and recovery. A randomized study was carried to access conditions for LMA insertion using Sevoflurane in 25 ASA I & II patients undergoing short duration surgeries.Subjects and Methods:This prospective study was conducted at Department of Anesthesiology and Critical Care, SVS Medical College and Hospital, Mahabubnagar, Telangana, India. After obtaining the institutional ethics committee and written informed consent from the patients, 25 subjects of either sex were included in this study. Age of the subjects was 18 to 60 years. Patients received injection Fentanyl 1 – 2mcg/kg prior to induction. All patients were pre-oxygenated for 3 min with 100% oxygen using a fresh gas flow of 81/min. All patients received inhalational induction with 8% Sevoflurane and O2 flow at 8 L/min with single vital capacity breathe technique. Loss of verbal contact was considered as the desired endpoint for induction, which was assessed by the response to calling out the patient’s name. Then the time of loss of eyelash reflex and jaw relaxation was assessed by anesthesiologist. After adequate jaw relaxation, LMA insertion was attempted.Results:The mean loss of verbal contact was 65.40±9.67second, while the mean for time for loss of eyelash reflex and jaw relaxation were found to be 81.20±9.39 seconds and 103.20 ±12.07 seconds respectively. The mean time for LMA insertion was 122.00±15.61 and the mean attempts for successful LMA insertion was 1.12±0.33. LMA insertion was easy in 23 cases as against difficult in 2 cases. In 2 cases transient cough and biting were recorded. LMA insertion was excellent and satisfactory in 88.0 and 12 percent. However, the mean heart rate at 5 minute after induction showed a significant fall at 5 minutes after induction. The mean values of SBP, DBP and MAP did not differ significantly at pre and induction. However, a significant decrease in SBP was noticed at 1, 2 and at 5 minutes.Conclusion:Sevoflurane is an smooth inhalation anesthesia with rapid onset with adequate jaw relaxation for insertion of LMA in Adults for short duration surgeries. Sevoflurane has got good hemodynamic profile with lesser complications owing to choice of inhalation agent for insertion of LMA.

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Monitoring of CO2 exchange during cardiopulmonary bypass: the effect of oxygenator design on the applicability of capnometry

Perfusion ◽

10.1177/026765919300800409 ◽

1993 ◽

Vol 8 (4) ◽

pp. 337-344 ◽

Cited By ~ 3

Author(s):

Juha Aittomäki

Keyword(s):

Cardiopulmonary Bypass ◽

Gas Flow ◽

Blood Gases ◽

Barometric Pressure ◽

Co2 Exchange ◽

Arterial Line ◽

Exhaust Gas ◽

Blood Samples ◽

Outlet Port ◽

Membrane Oxygenators

The correlation between pCO2 values in blood and in exhaust gas from the oxygenators was examined during cardiopulmonary bypass (CPB) using one bubble oxygenator and three membrane oxygenators. Forty-seven CPBs were performed, 17 with Compactflow® (Dideco, ltaly), 10 with Maxima® (Medtronic Inc., USA), 10 with Cobe CML®(Cobe Laboratories, USA) membrane oxygenators and 10 with Hi-Flex® (Dideco, Italy) bubble oxygenators. Blood samples were taken both from arterial and venous lines of the oxygenator. A capnometer was connected to the oxygenator gas exhaust port and CO2 fraction was measured at the time of drawing blood samples. CO2 pressure in the gas phase was calculated from the product of the CO2 fraction and water vapour- corrected barometric pressure. Blood gases were measured at 37°C and the pCO2 value was corrected to the temperature of the arterial line. The correlation between blood and exhaust gas pCO2 was good in all the oxygenators examined, ranging from 0.921 to 0.976. The standard error of estimate (SEE) was in the range of about ± 2 mmHg for all the oxygenators. The systematic error (slope and intercept of the correlation line) varied depending on the construction of the oxygenator, with countercurrent design having the best overall correspondence. Based on the results of this study it can be concluded that arterial or venous CO 2 pressure can be monitored with a capnometry device coupled to the oxygenator gas outlet port. The use of a 'target FCO2 line' or a calculator program is proposed in order to aid the perfusionist in adjusting the oxygenator gas flow to attain normocarbia during CPB.

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In vitro clearance of dexmedetomidine in extracorporeal membrane oxygenation

Perfusion ◽

10.1177/0267659112456894 ◽

2012 ◽

Vol 28 (1) ◽

pp. 40-46 ◽

Cited By ~ 43

Author(s):

D Wagner ◽

D Pasko ◽

K Phillips ◽

J Waldvogel ◽

G Annich

Keyword(s):

Extracorporeal Membrane Oxygenation ◽

Membrane Oxygenator ◽

Ecmo Circuit ◽

Membrane Oxygenation ◽

Concentration Changes ◽

Membrane Oxygenators ◽

Serial Samples ◽

Ecmo Therapy ◽

Time Point

Dexmedetomidine (DMET) is a useful agent for sedation, both alone and in combination with other agents, in critically ill patients, including those on extracorporeal membrane oxygenation (ECMO) therapy. The drug is a clonidine-like derivative with an 8-fold greater specificity for the alpha 2-receptor while maintaining respiratory and cardiovascular stability. An in vitro ECMO circuit was used to study the effects of both “new” and “old” membrane oxygenators on the clearance of dexmedetomidine over the course of 24 hours. Once primed, the circuit was dosed with 840 μg of dexmedetomidine for a final concentration of 0.9 μg/ml. Serial samples, both pre- and post-oxygenator, were taken at 5, 60, 360, and 1440 minutes. Concentrations of the drug were expressed as a percentage of the original concentration remaining at each time point, both for new and old circuits. The new circuits were run at a standard flow for 24 hours, after which time the circuit was considered old and re-dosed with dexmedetomidine and the trial repeated. Results show that dexmedetomidine losses occur early in the circuits and then continue to decline. Initial losses in the first hour were 11+-65% and 59-73% pre- and post-oxygenator in the new circuit and 36-50% and 42-72% in the old circuit. The clearance of the drug through the membrane oxygenator exhibits no statistical difference between pre and post or new and old circuits. Dexmedetomidine can be expected to exhibit concentration changes during ECMO therapy. This effect appears to be more related to adsorption to the polyvinyl chloride (PVC) tubing rather than the membrane oxygenator. Dosage adjustments during dexmedetomidine administration during ECMO therapy may be warranted in order to maintain adequate serum concentrations and, hence, the desired degree of sedation.*(Lack of equilibrium)

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