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L Beydon

Publications and source records attributed to L Beydon.

85 records · Page 5Linked to original sources
PubMed1992

Can portable chest x-ray examination accurately diagnose lung consolidation after major abdominal surgery? A comparison with computed tomography scan.

PURPOSE: To prospectively quantify the degree of accuracy of portable chest x-ray film examination in the detection of postoperative lung consolidations. STUDY: Nineteen patients had a chest x-ray film and computed tomography (CT) scan the day before and 48 h following elective abdominal aortic replacement. RESULTS: The diagnosis of lung consolidations by x-ray film examination showed sensitivity of between 0.33 and 1.00, depending on the lung zone considered (lower at the lung bases). Specificity always was greater than 0.79. Radiologic lung volume decreased 16 percent postoperatively (p < 0.01) on average and noninflated parenchyma increased by a factor of 3 (p < 0.0001). Postoperatively, PaO2 correlated with the amount of condensed lung by CT scan (p < 0.002). CONCLUSION: In postoperative conditions, x-ray film examination is a method which presents good specificity but poor sensitivity in the diagnosis of lung consolidations.

Abdomen↗
PubMed1991

Pressure support ventilation using a new tracheal gas injection tube.

In order to explore new types of jet ventilation, we tested a tracheal gas injection tube (TGIT) which included six thin capillaries and provided high pressure injection. The driving pressure was chosen to yield a plateau of inspiratory tracheal pressure of 10 cm H2O. An original controller was built to monitor spirometry and trigger injection in order to deliver both pressure controlled ventilation (PCVTGIT) and a new mode of inspiratory pressure support jet ventilation (IPSTGIT). The PVCTGIT mode maintained the same end-tidal carbon dioxide concentration as conventional ventilation with the same tidal and minute ventilation. We studied 10 patients after abdominal surgery. During spontaneous breathing, the patients were allowed to breathe through the tube, successively with and without IPSTGIT. IPSTGIT, compared with spontaneous breathing increased minute ventilation (from 5.7 (SD 1.6) to 7.1 (1.7) litre min-1) (P less than 0.001). It reduced the total work of breathing (from 0.625 (0.223) to 0.263 (0.151) J litre-1, respectively) (P less than 0.01) and the occlusion pressure (from 2.62 (1.28) to 1.36 (0.74) cm H2O, respectively) (P less than 0.01). It is concluded that this TGIT used with a specific system for sensing and triggering ventilation allows inspiratory pressure support during low frequency jet ventilation.

Female↗
PubMed1991

Changes in the distribution of ventilation and perfusion associated with separation from mechanical ventilation in patients with obstructive pulmonary disease.

A trial of separation from mechanical ventilation may induce an abnormal respiratory pattern and a maldistribution of ventilation-to-perfusion ratios (VA/Q), especially in patients with chronic obstructive pulmonary disease. This study was designed to assess the effects of three different modes of ventilation on the distribution of global and also regional VA/Q in eight patients with chronic obstructive pulmonary disease recovering from acute respiratory failure who remained dependent on mechanical ventilation after more than 5 days of attempted separation from the ventilator. VA/Q distribution was assessed using the multiple inert gas and isotopic scanning methods after 30 min each of controlled mechanical ventilation (CMV), 10 cmH2O inspiratory pressure support, and spontaneous breathing (SB). Controlled ventilation was provided at a respiratory rate ranging from 12 to 18 breaths per min and a tidal volume of 8 ml.kg-1. In comparison to CMV, SB resulted in a decrease in tidal volume (from 512 +/- 144 to 301 +/- 102 ml, P less than 0.01), and an increase in respiratory rate (from 15.5 +/- 3.2 to 27.3 +/- 15.0 breaths per min, P less than 0.05), which increased dead space (+7.1% of minute ventilation), cardiac output (+36%), and the perfusion to areas of low VA/Q (+8.9% of cardiac output) (P less than 0.05, P less than 0.001, and P less than 0.05, respectively). Isotopic scans revealed a horizontal craniocaudal difference of VA/Q in all modes, with the lowest VA/Q zones at the basal part of the lungs (mean basal VA/Q 0.58 in SB and 1.05 in CMV).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[Opening of a foramen ovale during liver transplantation. The value of transesophageal echocardiography].

A case is reported of a foramen ovale becoming patent during orthotopic liver transplantation (OLT). The patient had a hepatoma secondary to post-hepatitis cirrhosis. Monitoring included transesophageal echocardiography (TEE). A veno-venous shunt between the right femoral, portal and left axillary veins was used so as to maintain the venous return during portal and caval clamping. The patient's haemodynamic state remained quite stable throughout this period, and no vasoactive drug was required. Five min after graft reperfusion, pulmonary arterial pressure increased suddenly (mean PAP: 27 mmHg). TEE revealed paradoxical movements of the atrial septum. Colour coded Doppler ultrasound showed blood flowing from the right to the left atrium through a patent foramen ovale. Fifteen min later, mean PAP decreased (18 mmHg) and TEE no longer showed any flow between the two atria. Several studies have reported transient pulmonary hypertension after unclamping when the donor liver is reperfused. This could induce right ventricular failure, with transient inversion of the atrial pressure gradient, which, in turn, could result in a right-to-left shunt through a patent foramen ovale. TEE can monitor regional and overall left ventricular function as well as the atrial septum. This technique might therefore to be useful for cardiac monitoring during OLT.

Cardiomyopathies↗
PubMed1990

Pulmonary volume measurements during high-frequency jet ventilation in anesthetized man.

To assess the validity of indirect spirometry during conventional intermittent positive-pressure ventilation (IPPV) and high-frequency jet ventilation (HFJV), we measured changes in functional residual capacity (delta FRC) and tidal volume (VT) with two external strain gauges in eight sedated and paralyzed patients. The thoracic and abdominal gauges were calibrated simultaneously in quasi-static and dynamic conditions. The delta FRC measured during HFJV (1 to 5 Hz) and the VT measured during IPPV (0.25 Hz) were found to be equivalent by the two gauges in most patients (r = .90 and r = .99, respectively), but no correlation was found between the VT values inferred by each gauge in HFJV (r = .54). During HFJV, spectral analysis of the gauge signals showed important damping of the abdominal motion (AB) and an amplification of the thoracic displacements (RC) in four patients when measurements were taken at greater than 3 Hz. We conclude that, provided the partition of the volume between AB and RC remains constant, indirect spirometry may measure VT in IPPV and delta FRC in HFJV, but it fails to measure VT accurately during HFJV.

Anesthesia↗
PubMed1988

Inspiratory work of breathing during spontaneous ventilation using demand valves and continuous flow systems.

To diminish the work of breathing, some demand valve systems are equipped with inspiratory pressure support (IPS). The purpose of this study was to evaluate the work performed during spontaneous breathing using the Siemens Servo 900C ventilator (SVC) at the minimal IPS level available, and comparing it with a demand valve ventilator without IPS, the Ohmeda CPU1 (CPU1), and with a home-built continuous flow system (CFS). We found a larger minute ventilation and inspiratory peak flow with the SVC and the CFS than with the CPU1 (p less than 0.05). When the work of breathing was measured at the airway opening, we found that the CFS led to the least amount of work (0.17 +/- 0.05 J.L-1, p less than 0.05). Additionally, this work was strikingly less for SVC than for CPU1 (0.22 +/- 0.06 versus 0.42 +/- 0.10 J.L-1, p less than 0.001) as a result of a higher flow supplied by the SVC. By contrast, the work measured using the esophageal pressure, i.e., including the work dissipated on the lung and airways, was significantly reduced with the CFS (1.34 +/- 0.45 J.L-1, p less than 0.05), but surprisingly not different between SVC and CPU1 (1.49 +/- 0.57 versus 1.54 +/- 0.51 J.L-1). We conclude that the absence of a demand valve in CFS involves the lowest work of breathing. Likewise, the high flow capability in SVC reduces the work necessary to overcome the circuit and demand valve resistances.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Respiratory effects of nitrous oxide during isoflurane anaesthesia in children.

Respiratory effects of nitrous oxide and isoflurane were studied in 13 children (mean age 45.6 +/- 19.3 months, mean weight 14.9 +/- 4.8 kg) during surgery under continuous extradural anaesthesia. Three different anaesthetic states were studied: isoflurane 0.5 MAC in oxygen (27 study periods), isoflurane 0.5 MAC with 50% nitrous oxide (32), isoflurane 1 MAC in oxygen (25). End-tidal carbon dioxide (PE' CO2) and isoflurane, respiratory indices (tidal volume, VT; minute ventilation, VE; mean inspiratory flow, VI; respiratory frequency f, effective inspiratory timing TI/Ttot were measured. The addition of nitrous oxide (comparison of respiratory variables obtained in 25 successive periods at (1) and (2)) produced a significant increase in PE' CO2' significant decreases in VT, VE and VI, a significant increase in f. The increase in alveolar concentration of isoflurane ((1) compared with (3) in 25 successive periods) was associated with a significant increase in PE' CO2' significant decreases in VT, VE, VI and a significant increase in f. The equipotent anaesthetic states (2) and (3) were compared in 21 successive periods. In children, the net result of substituting nitrous oxide for an equal MAC fraction of isoflurane was to produce a smaller decrease in VT responsible for a smaller decrease in VE without significant change in respiratory rate.

Anesthesia, Inhalation↗
PubMed1986

Ventilatory changes during nitrous oxide isoflurane anaesthesia in children.

The changes in ventilatory variables under nitrous oxide isoflurane anaesthesia were studied in 10 children (mean age 46 +/- 13.4 months, mean weight 16.2 +/- 2.1 kg). Measurements of flow and volume were performed by pneumotachography. PE'CO2 was measured by capnography. The following variables (VE, VT, TI/TTOT, VI, PE'CO2) were measured or calculated under three increasing inspired isoflurane concentrations (0.75%, 1.5%, 2.25%). At each level of anaesthesia, ventilatory changes during exposure to an inspired CO2 fraction of 2% were studied. The increase in the inspired concentration of isoflurane was associated with a decrease in alveolar ventilation. PE'CO2 increased significantly with increasing depth of anaesthesia. The respiratory rate was slightly increased under light nitrous oxide isoflurane anaesthesia, but no further changes were observed with increasing depth of anaesthesia, although the children were breathing a mixture of nitrous oxide and oxygen. The ventilatory response to a raised inspired CO2 is markedly decreased under light nitrous oxide isoflurane anaesthesia, and decreases significantly with increasing depth of anaesthesia. In response to a raised CO2, VE, VT and VI increase, but respiratory rate decreases or remains constant and TI/TTOT is unchanged.

Anesthesia↗
PubMed1984

[Hemiplegia during carbon monoxide poisoning revealing multiple cerebral artery abnormalities including the hypoglossal artery].

Hemiplegia after carbon monoxide (CO) poisoning is rare since only 9 such lesions have been reported from among 1480 cases of poisoning. The patient reported was a 43 year-old man with a left hemiplegia with coma following CO poisoning. Right carotid angiography demonstrated a hypoglossal artery supplying both posterior cerebral arteries. Left carotid angiography showed a dolichocarotid artery supplying the territories of the anterior and middle cerebral arteries on both sides. Complete regression of the hemiplegia occurred after 2 months following rapid administration of hyperbaric oxygen. Normal CT scan images and cerebral blood flow rates on follow-up examination suggest that the left hemiplegia was due to the combined effects of arterial anomalies and CO poisoning.

Abnormalities, Multiple↗
PubMed1983

[Neurogenic tumor of the anterior mediastinum. An uncommon diagnosis: neurofibroma of the vagus].

Case report of an endothoracic neurofibroma of the left vagus nerve, presenting as an anterior mediastinal mass in a 62 years old man without other signs of Recklinghausen's disease. Rarity of such cases is noted. Previously published sixty one reports are studied. Only four are localised in anterior mediastinum. The authors emphasize absence of specific signs of vagal involvement, importance for diagnosis of surgical extirpation, and mildness of post operative course.

Cranial Nerve Neoplasms↗