[Anaesthesia for a non cardiac surgery in a patient with an Eisenmenger syndrome. Interest of a non invasive haemodynamic monitoring]. / Anesthésie pour une chirurgie non cardiaque chez une patiente avec un syndrome d'Eisenmenger. Intérêt de la surveillance hémodynamique non invasive.

Patients with an Eisenmenger syndrome have an instuble hemodynamic status. During a general anaesthesia, the intracardiac shunt has to maintain the correct orientation and volume, adapted to each patient, in such a condition, to avoid the risk of hypoxemia and cardiac failure. The haemodynamic monitoring with a Swan Ganz catheter could be useful. But it is necessary to evaluate the advantage and the risks when the technique is used in these pathological circumstances. Moreover, when the cardiac output is measured with the thermodilution technique, the right-left intra cardiac shunt volume, is not taking into account. The continuous haemodynamic monitoring, with a simplified transoesophageal echo-Doppler system, as it was done in this case, allows appreciate the real quantitative variations of the shunt. In this way the more adequate calculation of some others haemodynamic parameters, over all the total systemic vascular resistances, allows a more precise therapeutic approach.

Noninvasive aortic blood flow measurement using an intraesophageal probe.

The continuous measurement of cardiac output by the thermodilution technique is invasive, impractical and unpleasant for the patient. This paper describes the measurement of aortic blood flow with a specially designed intraesophageal echo Doppler probe. An A-scan unit allows the measurement of the diameter of the thoracic aorta and a continuous wave Doppler velocimeter is used for measurement of instantaneous blood flow velocity. In vitro experimental results as well as clinical studies are presented.

Assessment of a potentially noninvasive method for monitoring aortic blood flow in children.

Ultrasonic methods have rendered possible noninvasive quantitative blood flow measurement. In this work, a method is proposed to measure aortic blood flow in children by means of a specially designed miniaturized esophageal probe and an autonomous apparatus combining an M-mode imaging system and a pulsed Doppler. In vivo experimental results in animals are presented and demonstrate the interest of simultaneous and continuous measurement of aortic diameter and blood flow velocity giving accurate measurements. A 0.94 correlation coefficient is found when comparing blood flow in the descending aorta measured using this method and using an electromagnetic flowmeter.

[Evaluation of tissue perfusion by simultaneous monitoring of aortic flow rate and capnography]. / Evaluation de la perfusion tissulaire par surveillance simultanée du débit aortique et de la capnographie.

Ten patients under general anaesthesia were subjected to non-invasive haemodynamic monitoring, together with arterial gasometry and capnography. When enflurane was administered for maintenance anaesthesia, a 33 percent fall in aortic flow rate was observed (P less than 0.01), together with prolongation of the pre-ejection period and left ventricular pre-ejection/ejection ratio, an increase of central venous pressure and total vascular systemic resistances. The end-expiratory CO2 (Pet CO2) was reduced by 13 percent (P less than 0.05). There was no significant variation in arteriolo-alveolar CO2 difference (P(a-A)CO2). Under dobutamine (mean dose: 3.4 +/- 0.5 micrograms/kg/min), the haemodynamic parameters returned to their initial values. Pet CO2 rose above its initial level (+ 12 percent; P less than 0.05), but P(a-A)CO2 was not significantly modified. The variations of Pet CO2 were parallel with those of aortic flow rate. It is concluded that the changes in Pet CO2 observed during haemodynamic modifications could be used as markers for qualitative evaluation of tissue perfusion.

[Aortic flow measurement by transesophageal Doppler effect]. / Débitmétrie aortique par effet Doppler transoesophagien.

Continuous measurement of cardiac output by thermodilution is invasive, impractical and unpleasant for the patient. We propose to measure descending aortic blood flow with a specially designed intra-oesophageal Doppler echo probe. The apparatus is composed of two main parts. First an A scan system makes possible the measurement of the diameter of the vessel, second a continuous wave velocimeter is used to measure the spatial mean velocity of the blood. An output calculator determines the descending aortic blood flow. The oesophageal catheter contains three ultrasonic transducers at its tip mounted on an epoxy resin bracket produced by moulding. They are connected to a flexible hose placed inside a flexible polyvinyl sheath whose outer diameter is 6.8 mm and length is 50 cm. A cylindrical latex balloon is mounted on this sheath which is water inflated to minimum pressure, ensuring a good ultrasonic coupling between the transducers and the oesophageal wall. Connection between the probe and the apparatus is made by three coaxial cables. Three isolator-transformers are built into the connector cable to ensure a safe electrical circuit. After having bled the probe of any air, the balloon is deflated. The probe is gently introduced into the oesophagus by nasal or oral route until the transducers are situated between the 5th and 6th vertebra. The balloon is then inflated to minimum pressure with 10 ml of distilled water contained in a syringe. To find the aorta, the velocimeter is first used like a Doppler stethoscope. The probe is rotated into a position corresponding to the maximum level of Doppler signal.(ABSTRACT TRUNCATED AT 250 WORDS)

[Central venous infusion of dopamine. Changes in dose during central venous pressure measurement]. / Perfusion de dopamine par voie veineuse centrale. Variation de la dose lors de la mesure de la pression veineuse centrale.

The changes in the doses of dopamine administered at a steady rate which occur during central venous pressure (CVP) measurement were studied. A workbench model with a single lumen central venous catheter was devised with which a mathematical model was constructed to calculate the alterations due to changes in different variables: central venous pressure, dopamine dose, collateral infusions. The average time for CVP measurement was 2 min. The volume of 5% glucose solution filling the manometer was 2.3 ml. The dopamine bolus generated by CVP measurement was equivalent to a dose of 85 micrograms.kg-1 x min-1. The delay required for a return to the initial dose was 2 h 42 min. Changes in CVP led to inversely proportional changes in dopamine dose. These also depended on the level to which the measuring tube was filled before carrying out the measurement. High initial rates of dopamine infusion required shorter times for a return to initial dopamine doses. The bolus and time for recovery were also inversely proportional to the volume of infusion fluids given at a steady rate on the same venous line. This model was tested in a patient suffering from bacterial pneumonia and septic shock (60 years, 55 kg). CVP measurement resulted in a bolus dose of 17 micrograms.kg-1 x min-1, leading to a 43% decrease in aortic flow rate and 60% in the ejection volume. After about 25 min, heart rate and mean arterial blood pressure had returned to their initial values, although aortic flow rate remained 30% below initial values. This problem is also met with other drugs, such as heparin.(ABSTRACT TRUNCATED AT 250 WORDS)

[Diagnosis of heart arrest caused by CO2 embolism during laparoscopic surgery by monitoring of aortic blood flow and capnography]. / Diagnostic par surveillance du débit aortique et du capnogramme d'un arrêt circulatoire par embolie de CO2 au cours de la chirurgie laparoscopique.

We report the case of a 25-year-old woman undergoing a laparoscopic cholecystectomy, who suffered, one min after the beginning of intraperitoneal insufflation of CO2 (2.5 L at a pressure of 10 mmHg), a sudden decrease to 0.8 L.min-1 of the aortic blood flow (ABF), monitored in the descending aorta by an oesophageal echo-Doppler probe, associated with a decrease of PetCO2 to 15 mmHg and of SpO2 readings to 88%. Despite the lack of simultaneous changes in heart rate and arterial pressure, pulmonary gas embolism (GE) was suspected. The pneumoperitoneum was exsufflated and CPR was started because of circulatory inefficiency. Ten min later, efficient spontaneous cardiac activity restarted, whereas PetCO2 and ABF returned rapidly to normal values. At this time, a typical gas noise was clearly obtained through the oesophageal Doppler transducer. The patient remained in deep coma (GCS:6) with a left sided hemiplegia. However, she fully recovered after four sessions of hyperbaric oxygenation. Simultaneous continuous monitoring of ABF and PetCO2 allows an undelayed recognition of major circulatory disturbances, before significant changes in heart rate and arterial pressure occur.

[Noninvasive hemodynamic monitoring in gynecologic laparoscopy]. / Surveillance hémodynamique non invasive dans la coelioscopie gynécologique.

A new non-invasive haemodynamic monitoring technique was investigated on twenty female patients submitted to gynaecological laparoscopy under general anaesthesia. Continuous aortic output was measured with an echo-Doppler oesophageal probe specially developed by the authors. Peritoneal insufflation was performed with an average of 4 +/- 0.750 l CO2 at an average insufflation rate of 0.666 l X min-1; intraperitoneal pressure increased on average by 11.57 +/- 1.60 mmHg during insufflation. Aortic output changes were related to changes in the patient's position. In initial horizontal dorsal decubitus position, average aortic output was 2.83 +/- 0.642 l X min-1. Trendelenburg position (28 +/- 2 degrees) induced a transient 9.54% increase (p less than 0.05), while a return to the horizontal position was marked by an 11.3% increase (p less than 0.01) of the aortic output. No significant change was observed during insufflation and exsufflation (-2.13 and -5.3% respectively). Mean arterial pressure rose by 16.4% after insufflation (initial values: 90 +/- 15.08 mmHg; p less than 0.01). Total vascular systemic resistances were significantly higher at the end of insufflation (2.999 +/- 376 dyn X cm X s-5; + 18.04%; p less than 0.05). Heart rate did not change significantly. Aortic output monitoring with this non-invasive, easy-to-handle technique enabled early detection of haemodynamic changes during laparoscopy. These changes frequently preceded significant blood pressure or heart rate variations.

[Carotid endarterectomy under remifentanil]. / Endarterectomía carotídea bajo remifentanilo.

OBJECTIVE: Carotid endarterectomy can be performed under general or locoregional anesthesia. If locoregional anesthesia is chosen, the state of awareness of the patient allows for direct viewing of the effect of vascular clamping of the corresponding neurological territory. We present the results of an anesthetic procedure using only an analgesic in patients who were intubated and ventilated but with a level of consciousness that allowed us to view the effect of carotid clamping on motor functions. METHOD: Forty-eight patients, ASA II-III, underwent surgical carotid endarterectomy. The anesthetic protocol began with preoxygenation for 2 min; induction with remifentanil 0.75-1 microgram kg-1 for 2 min., followed by perfusion of 1 microgram/kg-1.min-1 of remifentanil and propofol 1 microgram/kg-1; and orotracheal intubation by local anesthesia of the glottis with 5% lidocaine spray. Ventilation was with FiO2 100%, FR 12 min. and VT 8 ml. kg-1. For maintenance the dose of remifentanil was regulated to obtain a coordinated motor response (maximum 1.5 microgram/kg-1.min-1, minimum 0.35 microgram/kg-1. min-1). For all patients we monitored hemodynamics continuously and non-invasively, including aortic output by the transesophageal Doppler echocardiography. RESULTS: The objective of anesthesia was reached in all the patients. The most common hemodynamic alterations were bradycardia (28), arterial hypotension (25), elevated blood pressure (3) and altered aortic output. All changes were corrected quickly with the treatment used, guided by the evolution of hemodynamic parameters. Postanesthetic recovery came in less than 4 min. The only episodes of hyper -and hypotension consisted of a few episodes of mild hyper- (12) and hypotension (1), which were soon corrected. No alterations attributable to hemodynamic instability occurred. During surgery, an intracarotid shunt was necessary in only one patient. Three suffered surgically-related neurological complications after the operations. No complications could be attributed to anesthesia. DISCUSSION: An advantage of this technique is that the duration of anesthesia is not limited, with adequate ventilation and maintenance of an adequate state of consciousness for clinical evaluation of the repercussions of carotid clamping. Hemodynamic monitoring detected the appearance of imbalances requiring therapeutic intervention. The procedure is interesting provided it is performed according to a strict protocol, with continuous clinical and instrumental monitoring of the patient's status.

[Detection of microbubbles formed in the blood/CO2 interphase during decompression in barometric conditions similar to laparoscopy]. / Detección de microburbujas formadas en la interfase sangre/CO2 durante la descompresión en condiciones barométricas similares a las de la laparoscopia.

HYPOTHESIS AND OBJECTIVES: Intraperitoneal insufflation (IPI) with CO2 during laparoscopic surgery establishes a pressure gradient that determines the passage of gas from the peritoneal cavity to the blood and surrounding tissues. The transport and clearance of CO2 are assured by proper sweeping when regional blood flow is adequate in volume and distribution. But if IPI hyperpressure surpasses regional venous capillary pressure (10 to 15 mmHg) and there is no cardio-circulatory adaptation to the phenomenon, CO2 clearance may be compromised. Under these conditions, the expected post-insufflation increase in PetCO2 will not take place. Bearing in mind the physical characteristics of CO2, retention of this gas in the intraperitoneal cavity produces blood and tissue saturation under a higher-than-atmospheric pressure, after a certain period of time in contact. Rapid intraperitoneal decompression after laparoscopic surgery carries with it the risk of microbubble formation due to release of CO2 that had been dissolved under hyperbaric conditions. MATERIAL AND METHODS: To test this hypothesis, the barometric conditions of laparoscopy were reproduced inside an observation capsule containing blood and CO2. RESULTS: Magnification revealed that after decompression bubbles formed in the blood/CO2 interphase. The images were recorded on magnetic videotape. Thirty minutes after decompression, the bubbles could still be seen, even after the interphase was swept with a current of air. DISCUSSION: Rapid intraperitoneal decompression after laparoscopy can generate the formation of microbubbles which, if not eliminated, will give rise to local ischemic manifestations. This same decompression, correcting the local circulatory alterations and activating the CO2 transport that had been compromised, could introduce gas bubbles into the blood stream such as are responsible for delayed gaseous microembolism. The simultaneous observation of changes in PetCO2 (stability or post-insufflation decreases) and hemodynamic parameters during laparoscopy, would allow evolving anomalies to be detected early and therapeutic action to be taken to prevent the formation of microbubbles.

[Effect of dobutamine on the transport and consumption of oxygen during general anesthesia with enflurane]. / Efecto de la dobutamina sobre el transporte y consumo de oxígeno durante la anestesia general con enflurano.

We undertook a comparative study on the effects of dobutamine and placebo on hemodynamic parameters, O2 transport (DO2), O2 consumption (VO2, and acid lactic production during peripheral arterial surgery under general anesthesia with enflurane at a constant inspiratory concentration (1.2%). This study involved 18 patients older than 65 years (9 patients allocated in the dobutamine group and 9 in the placebo group). The hemodynamic course was monitorized by means of noninvasive methods such as the aortic output measured by continuous transoesophageal echo-Doppler. After introduction of enflurane into the circuit aortic output decreased by 39% in dopamine group and 36% in placebo. Total systemic vascular resistances increased by 52% in dopamine and by 48% in placebo treatment. DO2 showed a decrease of 39% in dopamine and 38% in placebo group. There were no appreciable differences in VO2 among the two groups. Recovery of hemodynamic parameters and DO2 was only observed in the dopamine group when the drug was perfused at a rate of 4 +/- 1.2 micrograms/kg/min. Dobutamine induced a transient increase of VO2 up to 225% of the baseline value. During the postanesthetic period VO2 and blood acid lactic were significantly higher in the dopamine than in the placebo group (192%, p less than 0.01 and 33%, p less than 0.05, respectively). The course of hemodynamic parameters, DO2, VO2, and blood acid lactic of dobutamine group appear to demonstrate that dobutamine perfusion reverts myocardial depression and improves cellular perfusion during general anesthesia with enflurane.

[Evaluation of tissue perfusion by simultaneous non-invasive monitoring of the hemodynamic profile and capnography]. / Evaluación de la perfusión tisular mediante la monitorización simultánea del perfil hemodinámico no invasivo y la capnografía.

OBJECTIVES: To assess the simultaneous variations in blood gases and CO2 tele-expiratory pressure (ETCO2) produced by changes in tissue perfusion in anesthetized patients with stable lung perfusion, alveolar ventilation and metabolic states. MATERIAL AND METHODS: Forty patients were divided into two groups. Group 1 included 20 ASA I patients undergoing orthopedic surgery on the lower extremities. Group 2 included 20 ASA I-III patients undergoing peripheral vascular surgery during which myocardial depression developed after isoflurane administration. The decrease in minute volume was measured in the descending aorta by esophageal ultrasound in both groups. Other hemodynamic parameters were measured by digital plethysmography. ETCO2 was measured by lateral aspiration capnography, and central venous pressure was measured in group 2 by subclavian venous catheter. Measurements were taken before and after release of the tourniquet in group 1, and before and after the decrease in minute volume (> 30%) in group 2. RESULTS: Release of the tourniquet after a mean compression time of 51 +/- 07 minutes produced an increase of 52% (p < 0.001) in minute volume in all patients in group 1; an increase of 23% (p < 0.001) in ETCO2; and a decrease of 60% (p < 0.001) in total vascular resistance. In group 2 a 15% decrease in ETCO2 (p < 0.01) was observed, coinciding with a 35% decrease in minute volume (p < 0.01). CONCLUSIONS: An increase in minute volume produces an increase in ETCO2 while a decrease in minute volume results in a decrease in ETCO2. This means that sharp changes in ETCO2 may be useful in judging the degree of change in tissue perfusion when other parameters like alveolar ventilation, lung perfusion and metabolic rate remain constant.

[Nicergoline to reduce intraoperative blood pressure increases in hypertensive patients]. / La nicergoline pour réduire la poussée tensionnelle per-opératoire des hypertendus.

In order to test the therapeutic action of nicergoline during peroperative arterial hypertension, an intravenous perfusion of 5 mcg/kg/mn average dose was given to 15 patients which presented a peroperative increase of Systolic Blood Pressure (SBP) greater than 30% when compared with preanaesthetic corresponding value. The haemodynamic evolution was monitored, using non invasive method (except for central venous pressure, CVP). Particularly Aortic Blood Flow (ASF) was measured by ultrasonic means using specially designed intraoesophageal probe and flow meter including A-Scan and Doppler Velocity meter. SBP increased in 43% during hypertensive peak (initial level mean 129, +/- 12.6 mmHg; hypertensive peak, mean 185 +/- 16.80 mmHg; p less than 0.001). Ten minutes after the beginning of nicergoline perfusion, SBP showed a significative decrease (mean 141.4 +/- 11.20 mmHg, +9%). At the end of operation the SBP was nearly to average initial value (mean 135, +/- 11.85 mmHg; +4.5%). Diastolic Blood Pressure and Mean Blood Pressure presented similar variations. ABF decreased significatively during hypertensive peak (Initial ABF value means 3.49, +/- 0.99 l/mn, hypertensive peak ABF value means 2.68, +/- 0.54 l/mn, -25%, p less than 0.01). Nicergoline perfusion induced a partial recovery of ABF (mean 3.23 +/- 0.56 l/mn, +8%, p less than 0.05). This one was confirmed at the end of operation (mean 3.6 +/- 0.56 l/mn; -4% N.S.). Heart rate did not change significantly during monitoring period. From this results is seems that nicergoline perfusion induces a protection of hypertensive patients during peroperative decompensation.

[Improving tissue perfusion without invasive monitoring. Apropos of a case]. / Optimisation de la perfusion tissulaire obtenue sans monitorage invasif. A propos d'un cas.

A case is reported of a 64 year old patient who suffered a septic shock after surgical treatment of a biliary peritonitis. Increasing myocardial contractility and aortic blood flow by dobutamine appeared ineffective; added norepinephrine infusion improved the peripheral perfusion. This clinical improvement in tissue perfusion was evaluated by non-invasive continuous monitoring of the haemodynamic profile, combining aortic blood flow measurement by a transoesophageal echo-Doppler and continuous measurement of end-tidal carbon dioxide.

[Dobutamine in vascular surgery]. / La dobutamine en chirurgie vasculaire.

The hemodynamic parameters of 12 patients operated on not a coronary vascular disease have been controlled by means of not invasive technic. The aortic output was measured by means of an oesophageal probe that associates echography and Doppler effect. A double blinded study was done by dividing the patients into two groups. The group 1 was subjected to a perfusion of dobutamine and the group 2 to a perfusion of a placebo during the operation. The group 1 showed a mean aortic output similar-level than before anesthesia one (3.40 +/- 0.61 l/min; 3.35 +/- 0.5 l/min) and 37% greater than group 2 (p less than 0.01), during operation period. The average systolic volume of group 1 was nearly similar at the initial one (46.5 +/- 12.92 ml; 40.8 +/- 8.2 ml) and 35% higher than group 2 (p less than 0.01). The cardiac frequency was higher (average 14 beats per minute) in the group 1 (p less than 0.01). The total systemic vascular resistance of group 1 were maintained in equilibrium and did not show any significative change. In opposition, group 2 showed a 207% increase in their vascular resistance, in relation to the initial values (p less than 0.01). These values were significatively higher that those of the group 1 (p less than 0.00). Mean diuresis was of 144 +/- 41.5 ml/h for group 1 and 43.6 +/- 10.9 ml/h for group 2 (p less than 0.001). In group 2 the H+ concentration increased from 33 to 39 nmol/l (p less than 0.01) and it was higher (p less than 0.01) than group 1.(ABSTRACT TRUNCATED AT 250 WORDS)

[Dobutamine during anesthesia of patients at risk for heart failure. A controlled prospective multicenter study of 93 surgical patients over 64 years of age]. / Dobutamine pendant l'anesthésie de patients à risque de défaillance cardiaque. Etude multicentrique prospective contrôlée chez 93 opérés de plus de 64 ans.

Most anaesthetic agents cause cardiac depression possibly hazardous in the elderly, especially in presence of a poor cardiac reserve. Ninety-three patients undergoing non cardiac surgery lasting more than 90 min. were entered in a double-blind multicentre randomized trial. They were 65 year old or more and unaffected by evolutive angina pectoris. After insertion of a Swan Ganz catheter and an arterial cannula, anaesthesia was induced by thiopentone, fentanyl and 02/nitrous oxide (50%). Forty-five patients were infused dobutamine 7 micrograms.kg-1.min-1 (group D) from 10 min. after induction till the completion of surgery. Forty-eight patients received a placebo (group P). Haemodynamic parameters were recorded throughout anaesthesia and at its emergence. After induction, heart rate, pulmonary capillary wedge pressure and mean pulmonary artery pressure did not change significantly; mean arterial pressure, cardiac index, stroke index and left ventricular stroke work index decreased by 21, 33, 28 and 42% respectively (p less than 0.001); systemic and pulmonary arterial resistances increased by 12 and 37% respectively (p less than 0.001). In group P, these changes persisted throughout the procedure but, 30 min after extubation, cardiac index returned to control levels due to a 25% increase in heart rate; in this group 4 patients presented with both perioperative low cardiac output and persistent postoperative confusion. With dobutamine, haemodynamic parameters returned to preoperative values and heart rate increased by 12 b.min-1. More arrhythmias and hypertensive episodes but less hypotensions occurred in group D. Substantial haemodynamic changes occur during anaesthesia and surgery in elderly patients. Dobutamine corrects the peroperative decrease in cardiac output and blood pressure, and might prevent postoperative neurological disorders.