[Electronic tissue compensation for breast external radiotherapy: use of digital reconstructive radiography]. / Compensation électronique dans les traitements de cancer du sein par irradiation: utilisation des radiographies numériques reconstruites (digital reconstruct radiograph [DRR]).

PURPOSE: In case of external breast radiotherapy, the usual treatment consists of two tangential beams homogeneously attenuated by a dynamic or physics wedge in order to obtain the most homogeneous dose distribution as possible. Depending of the shape and size of the breast volume, we may observe with this technique dose heterogeneity over 20% from the recommendation of the International Committee on Radiation Units and Measurements (95-107%). We propose to study breast treatment planning by compensating tissues thickness in order to decrease dose heterogeneity observed on the dose distribution for conventional treatment. MATERIALS AND METHODS: We have segmented the initial tangential beams used for this kind of treatment into several smaller beams. Their shape was adapted to the distribution of the greys level on the DRR image. Therefore, we have compensated the thickness gradient and we have given the right dose to the right thickness group. RESULTS: Dose distribution performed with this method shows an improvement of the dose homogeneity in the three space dimensions and a decrease of the maximal dose between 5 and 10% over the ICRU recommendation. CONCLUSION: This technique allows us to perform breast irradiation on a single photon energy linac even if the treated volume presents important thickness gradient. However, in case of large breast, this method is not able to reduce the overdosage at the entry of the volume due to inappropriate photon energy relative to the breast thickness.

[Impact of computed tomography (CT) and 18F-deoxyglucose-coincidence detection emission tomography (FDG-CDET) image fusion for optimisation of conformal radiotherapy in non-small-cell lung cancers]. / Tomographie par émission de positons et détection en coïncidence (TEDC) et recalage d'images de simulation virtuelle par tomodensitométrie. Impact sur la planification de la radiothérapie conformationnelle des cancers bronchiques non à petites cellules.

UNLABELLED: To report a retrospective study concerning the impact of fused 18F-fluorodeoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and computed tomography (CT) images on three-dimensional conformal radiation therapy (3D-CRT) planning for patients with non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: One hundred and one patients consecutively treated for stages I-III NSCLC were studied. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same radiation treatment position. Images were coregistered using five fiducial markers. Target volume delineation was initially performed on the CT images and the corresponding FDG-PET data were subsequently used as an overlay to the CT data to define target volume. RESULTS: FDG-PET identified previously undetected distant metastatic disease in 8 patients making them ineligible for curative CRT (one patient presented some positive uptakes corresponding to concomitant pulmonary tuberculosis). Another patient was ineligible for curative treatment because fused CT/PET images demonstrated excessively extensive intrathoracic disease. The gross tumor volume (GTV) was decreased by CT/PET image fusion in 21 patients (23%) and was increased in 24 patients (26%). The GTV reduction was > or = 25% in 7 patients because CT/PET image fusion reduced pulmonary GTV in 6 patients (3 patients with atelectasis) and mediastinal nodal GTV in 1 patient. The GTV increase was > or = 25% in 14 patients due to an increase of the pulmonary GTV in 11 patients (4 patients with atelectasis) and detection of occult mediastinal lymph node involvement in 3 patients. Among 81 patients receiving a total dose > or = 60 Gy at ICRU point, after CT/PET image fusion, the percentage of total lung volume receiving more than 20 Gy (VL20) increased in 15 cases and decreased in 22 cases. The percentage of total heart volume receiving more than 36 Gy increased in 8 patients and decreased in 14 patients. The spinal cord volume receiving at least 45 Gy (2 patients) decreased. After multivariate analysis, one single independent factor made significant effect of FDG/PET on the modification of the size of the GTV: tumor with atelectasis (P = 0.0001). Conclusion. - Our study confirms that integrated hybrid PET/CT in the treatment position and coregistered images have an impact on treatment planning and management of patients with NSCLC. FDG images using dedicated PET scanners with modern image fusion techniques and respiration-gated acquisition protocols could improve CT/PET image coregistration. However, prospective studies with histological correlation are necessary and the impact on treatment outcome remains to be demonstrated.

[Impact of computed tomography (CT) and 18F-deoxyglucose positron emission tomography (FDG-PET) image fusion for conformal radiotherapy in esophageal carcinoma]. / Tomographie par émission de positons et fusion d'images de simulation virtuelle par tomodensitométrie. Impact sur la planification de la radiothérapie conformationnelle des cancers de l'oesophage.

PURPOSE: To study the impact of fused (18)F-fluoro-deoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and computed tomography (CT) images on conformal radiation therapy (CRT) planning for patients with esophageal carcinoma. PATIENTS AND METHODS: Thirty-four patients with esophageal carcinoma were referred for concomitant radiotherapy and chemotherapy with radical intent. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same radiation treatment position. PET-images were coregistered using five fiducial markers. Target delineation was initially performed on CT images and the corresponding PET data were subsequently used as an overlay to CT data to define the target volume. RESULTS: FDG-PET identified previously undetected distant metastatic disease in 2 patients, making them ineligible for curative CRT. The Gross Tumor Volume (GTV) was decreased by CT and FDG image fusion in 12 patients (35%) and was increased in 7 patients (20.5%). The GTV reduction was >or=25% in 4 patients due to reduction of the length of the esophageal tumor. The GTV increase was >or=25% with FDG-PET in 2 patients due to the detection of occult mediastinal lymph node involvement in one patient and an increased length of the esophageal tumor in the other patient. Modifications of the GTV affected the planning treatment volume (PTV) in 18 patients. Modifications of delineation of GTV and displacement of the isocenter of PTV by FDG-PET also affected the percentage of total lung volume receiving more than 20 Gy (VL20) in 25 patients (74%), with a dose reduction in 12 patients and a dose increase in 13 patients. CONCLUSION: In our study, CT and FDG-PET image fusion appeared to have an impact on treatment planning and management of patients with esophageal carcinoma related to modifications of GTV. The impact on treatment outcome remains to be demonstrated.

Comparison of two semicontinuous cardiac output pulmonary artery catheters after valvular surgery.

OBJECTIVE: To compare semicontinuous cardiac output (CCO) with bolus cardiac output (BCO), in the immediate postoperative period after valvular surgery, under hypothermic cardiopulmonary bypass with two CCO pulmonary artery catheters, based on the pulsed warm thermodilution technique, i.e., Opti-Q from Abbott or IntelliCath from Baxter-Edwards (Abbott and Baxter groups, respectively). DESIGN: Prospective study. SETTING: University hospital. PATIENTS: Forty-four adult patients scheduled for mitral and/or aortic valve surgery were randomized into two groups. Tricuspid or pulmonary valvulopathy diagnosed by echocardiography was excluded. INTERVENTIONS: Cardiac output was measured every 20 mins during the 3 postoperative hrs. BCO was the mean of three boluses (10 mL) of an ice-cold saline solution injected within 3 secs. CCO was the mean of two CCO values obtained in normal mode immediately before and after BCO measurements. MEASUREMENTS AND MAIN RESULTS: Two groups of 22 patients underwent 198 pairs of cardiac output measurements. The mean difference or bias was calculated as the difference between BCO and CCO, and precision was the SD of the mean bias. The limits of agreement were defined as bias +/- 2 SD. A two-sample Wilcoxon's test was used for comparison of bias and precision in sinus and non-sinus rhythm, and stable and unstable mean arterial pressure in each group and between the two pulmonary artery catheters. The coefficient of correlation was also calculated. Bias +/- precision was 0.066+/-0.526 L/min, r2 = .83, for the Abbott group, and 0.015+/-0.490 L/min, r2 = .85 (not significant), for the Baxter group. There was no significant difference within and between groups for bias and precision in sinus and non-sinus rhythm, nor in stable and unstable mean arterial pressure. CONCLUSIONS: This study, during the immediate postoperative period in valvular surgery under hypothermic cardiopulmonary bypass, showed a satisfactory correlation between CCO and BCO with the two systems.

Predictive factors for usefulness of fiberoptic pulmonary artery catheter for continuous oxygen saturation in mixed venous blood monitoring in cardiac surgery.

The main goal of this prospective study was to identify among cardiac surgery patients, usually monitored through a standard pulmonary artery catheter (PAC), those in whom a fiberoptic catheter oximeter to measure oxygen saturation in mixed venous blood (SVO2 PAC) would be most useful. Data from 286 patients who underwent coronary artery bypass graft (50%) or valvular surgery were recorded, including ASA physical status, New York Heart Association (NYHA) classification, and Parsonnet score (PS). Hemodynamic events and SVO2 changes were collected intra- and postoperatively until weaning from mechanical ventilation. The anesthesiologist in charge graded the usefulness of SVO2 PAC, and another anesthesiologist carried out a blindly controlled overall evaluation. Usefulness was defined as the presence of a change in therapeutic maneuver triggered solely by continuous SVO2 data that would not have occurred based on other routine parameters. SVO2 was also considered useful if earlier recognition of significant adverse events occurred. SVO2 PAC was useful in 57% of the patients. Independent predictive factors (multivariate analysis) for the perioperative usefulness of SVO2 in the whole population consisted of ASA class > or = 4 (P < 10(-5); relative risk [RR] 1.78, 1.51-2.07), mitral surgery (P < 10(-4); RR 1.72, 1.4-2.02), and NYHA score > or = 3 (P < 0.01; RR 1.66, 1.35-2.05). Independent predictive factors for the perioperative usefulness of SVO2 in the coronary artery bypass graft population were NYHA score > or = 3 (P < 10(-5); RR 1.90, 1.42-2.55) and ASA class > or = 4 (P < 0.01; RR 1.99, 1.51-2.63). The presence of three stenosed coronary arteries showed borderline significance (P < 0.06). Independent predictive factors for perioperative usefulness of SVO2 in the valvular population were mitral pathology (P < 10(-5)) and ASA class > or = 4 (P < 0.01). The receiver operator characteristic curve assessed the predictivity of the PS. SVO2 PAC was more useful in the group of patients with the greatest severity of illness (PS in useful group 17.0 +/- 10.3; in nonuseful group 8.7 +/- 6.6; P < 10(-4)). Intensive care unit duration and hospital stay in the useful group was prolonged compared with the nonuseful group. Similarly, morbidity was frequent in the useful group, although it was not always significantly different from the nonuseful group according to the type of complications. Mortality was comparable in the groups despite their different degree of illness and was reduced when taking into account the predictive and observed mortality provided by the PS. This study defined independent preoperative factors associated with SVO2 PAC monitoring and proposed a cutoff point above which SVO2 may be useful.

[Long-term development of aortic valve stenosis surgically treated at an advanced stage]. / Evolution à long-terme des rétrécissements aortiques opérés à un stade évolué.

From January 1972 to June 1990, 112 patients (39 to 83 years old), 67 males and 45 females were submitted to surgery for sever calcified aortic stenosis. 68 patients were in NYHA III (60.72%) and 44 in NYHA IV. Early mortality included 8 patients (7.14%), 6 died for cardiac reasons. Late mortality was 27.67%. Actuarial survival rate (including postoperative mortality) was 88.39%, 77.67%, 67.85% and 65.17% at one year, five, ten and fifteen years, respectively. Results were significantly correlated to left branch block on preoperative EKG, episodes of complete heart failure, significant coronary stenosis, the cardioplegia technique and the association with coronary bypass.

[Plasma concentrations of diltiazem and its metabolites in coronary surgery: relation with preoperative treatment]. / Concentrations plasmatiques du diltiazem et de ses métabolites en chirugie coronarienne: relation avec le traitement préopératoire.

Preoperative oral administration of calcium channel blocking agents has been found ineffective to prevent perioperative myocardial ischaemia. Our hypothesis was that low plasma concentrations may account for this inefficiency. Twenty-three male patients, scheduled for surgical myocardial revascularisation, were administered their usual anti-anginal treatment, including 180 to 360 mg of diltiazem since more than one week. The usual dosage was given at 8.00 p.m. on the day before surgery. On the morning of surgery, after withdrawal of a first blood sample, 60 mg of diltiazem were administered per month before the induction of anaesthesia. The anaesthesia was obtained with fentanyl, midazolam or flunitrazepam, pancuronium and isoflurane as required. The cardiopulmonary bypass (CPB) was associated with total haemodilution with Ringer's Lactate and a membrane oxygenator. A second blood sample was withdrawn after CPB. Plasma concentrations of diltiazem and its two active metabolites, N-monodemethyldiltiazem (MA) and desacetyldiltiazem (M1), were assessed by HPLC. Plasma diltiazem concentrations decreased from 78 +/- 66 (mean +/- SD) to 51 +/- 42 micrograms.l-1 (p < 0.05) with wide individual variations. These concentrations were under therapeutic levels in 18 out of 23 patients before (p < 0.05) with wide individual variations. These concentrations were under therapeutic levels in 18 out of 23 patients before induction and in 22 patients after CPB. The metabolite/diltiazem ratios remained constant. A dosage-plasma concentration relationship was observed preoperatively with diltiazem and MA. It is concluded that plasma concentrations of diltiazem should be optimized preoperatively in order to prevent myocardial ischaemia.

[Dopexamine: a new catecholamine used in the treatment of low cardiac output after heart surgery]. / Dopexamine: nouvelle catécholamine utilisable dans le traitement des syndromes de bas débit après chirurgie cardiaque.

The value of dopexamine hydrochloride, a beta 2 agonist with dopamine-like and weak beta 1 effects, for the treatment of low cardiac output was investigated in twelve patients. All had undergone cardiac surgery (valve replacement, aorto-coronary bypass), and had a cardiac index (C1) less than 21.min-1.m-2, low urine output (17 +/- 23 ml.h-1), and poor peripheral perfusion (peripheral cyanosis, cold hands and feet). Systolic arterial blood pressure was decreased, but over 80 mmHg. Diastolic pulmonary arterial or wedge blood pressure was more than 15 mmHg. Usual haemodynamic monitoring was carried out using arterial and Swan-Ganz catheters. Dopexamine hydrochloride doses were increased every 15 min by increments of 1 microgram.kg-1.min-1, up to a maximum dose of 8 micrograms.kg-1.min-1, so as to determine the optimal dose for each patient. This dose was then given for a period of up to 48 h. During the initial titration phase, heart rate increased by 37% from control at a dose of 4 micrograms.kg-1.min-1, this increase becoming less important at higher doses (13% at 8 micrograms.kg-1.min-1). Mean arterial blood pressure increased by 13% at a dose of 2 micrograms.kg-1.min-1. Mean pulmonary arterial blood pressure did not change significantly, but wedge pressure fell by 25% at 4 micrograms.kg-1.min-1. Simultaneously, CI increased by 56%, and systemic vascular resistances decreased by 31% (p less than 0.005). During the continuous steady rate infusion period, heart rate fell to a level of about 100 b.min-1.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hemodynamic effects of propofol]. / Effets hémodynamiques du propofol.

The new form of propofol gives the same haemodynamic effects as the old one (propofol diluted in cremophor EL). There are few experimental studies concerning the haemodynamic effects of propofol. In the dwarf pig, Glen and Turner found a fall in arterial blood pressure and peripheral resistances, whilst the heart rate and cardiac output rose. In man, studies have shown that propofol gives haemodynamic effects similar to the other intravenous anaesthetic drugs, and especially thiopentone. In subjects with a healthy heart, and for doses included between 1.5 and 2.5 mg X kg-1, propofol gave a 25 to 30% fall in arterial blood pressure. There are also a 20% fall in peripheral resistances and a small fall (10%) in cardiac output. Blood pressure returned to its initial level 3 to 5 min after the injection. The heart rate was not much changed, and rather slowed, perhaps because of central vagotonia. When propofol was used to maintain anaesthesia, either by repeat injections, or by infusion, with the patient breathing spontaneously and not undergoing painful stimuli, blood pressure and heart rate remained steady within 55 to 65% of their initial values. Propofol appeared to avoid to some extent the increase in blood pressure and heart rate seen during intubation. When propofol and fentanyl were used together, the cardiovascular effects were more pronounced than when they were used alone. Moreover, propofol appeared to limit to a large extent the hypertension due to intubation and sternotomy in patients undergoing aorto-coronary arterial graft surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

[Use of propofol in anesthesia in cardiac surgery. Preliminary results]. / Utilisation du propofol pour l'anesthésie en chirurgie cardiaque. Résultats préliminaires.

Nine patients, all NYHA class III and IV, who were to undergo surgery with cardiopulmonary bypass, were divided into two groups. All nine were premedicated with 2 mg flunitrazepam orally 90 min before surgery. Group A consisted in five men, mean age 53 years (extremes: 43 and 73), with no significant difference in weight and body surface area, who were to undergo aortic valve replacement (2), mitral valve replacement (2), and aortic and mitral valve replacement (1). They were given 1.5 mg X kg-1 propofol as a bolus at induction, followed by an infusion of 50 micrograms X kg-1 X min-1 propofol. Group B consisted in four patients, two men and two women, mean age 60 years (extremes: 49 and 76), with no significant difference in weight and body surface area, who were to undergo aortic valve replacement (3) and corrective surgery for left ventricular aneurysm (1). They were given 2 mg X kg-1 propofol as a bolus at induction, followed by an infusion of 100 micrograms X kg-1 X min-1 propofol. All the patients were intubated after 0.1 mg X kg-1 pancuronium; they were given 10 micrograms X kg-1 before intubation and 10 micrograms X kg-1 before skin incision. Repeat doses of fentanyl and pancuronium were given as required. The haemodynamic parameters studied were: heart rate, systolic, diastolic and mean blood pressures, central venous pressure, mean pulmonary pressure, wedge pressure, and cardiac output measured by thermodilution. The following indices were calculated: cardiac index, systolic index, right and left systolic work indices, and pulmonary and systemic vascular resistances.(ABSTRACT TRUNCATED AT 250 WORDS)

[Treatment of low cardiac output following extracorporeal circulation with captopril]. / Traitement du bas débit cardiaque post-CEC par le captopril.

Seven patients in low-output cardiac failure, resistant to conventional vasodilators and inotropic agents, following surgery with extra-corporeal circulation were given oral captopril, an angiotensin converting enzyme inhibitor. The effects of captopril on haemodynamic and renal function were studied after 2, 6, 12 and 24 hours of treatment. After two hours, there was a mean reduction in systemic arterial resistance of 29%, in pulmonary arterial resistance of 18% and in pulmonary wedge pressure of 15%. The mean increase in the cardiac index was 28%. This marked initial haemodynamic improvement was either maintained or increased over the rest of the 24 hours. By 24 hours there had been a mean increase in urinary sodium excretion of 200%. The urinary sodium/potassium ratio increased from 0.62 to 1.45. Oral captopril thus seems suitable for treating low-output cardiac failure following surgery requiring extra-corporeal circulation.

[Modification of a continuous positive airway pressure in view of its use in postoperative resuscitation in cardiovascular and thoracic surgery]. / Modification du circuit de CPAP "P.P" en vue de son utilisation en réanimation postopératoire de chirurgie cardiovasculaire et thoracique.

This paper describes a modification of a CPAP "P.P" circuit. This modified circuit is used to wean from artificial ventilation: 1) Patients exhibiting an hypoxia when undergoing a T piece trial with high FiO2. 2) Patients presenting pulmonary pathology before the operation. 3) Patients with cardiogenic shock so long as controlled mandatory ventilation is not an absolute requirement. This modification of a CPAP "P.P" circuit may have general use in the post-operative care after cardiovascular and thoracic surgery.