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Biomedical subjects

P Viars

Publications and source records attributed to P Viars.

At least 127 records · Page 7Linked to original sources
PubMed1989

[Successful separation in 1974 of craniopagus twins united at the vertex. Indications, technics, follow-up after 14 years].

On July 22, 1974, 55 days after delivery, the separation of female craniopagus twins united at the vertex was performed. This case was very similar to the case published by Voris in 1957 after separation in 1955. Surgery was decided because the neurological examination was normal in both twins, because there was no body malformation, because the angiogram as well as isotopic scintigraphy showed two normal brains, two superior sagittal sinuses and two torcular areas with a short venous union in the middle of the bone defect. In addition, Sophie and Sonia were suffering from respiratory disturbances due to their position. Surgery was easy (90 min) using the operative microscope; intubation and placing intravascular tubes for hemodynamic monitoring were difficult and lasted 4 hours. After all it took 14 years and 23 operations to complete the reconstructive surgery of the bone and skin. Cranioplasty was finally performed using vitallium plates. On their 14th birthday a neuropsychological investigation was performed with an IQ of 94 in Sophie and 76 in Sonia. Both girls are nubile and enjoy a normal school attendance.

Adolescent↗
PubMed1989

Clinical use of high frequency ventilation.

High-frequency jet ventilation (HFJV) and high-frequency positive pressure ventilation (HFPPV) occupy a specific place in the wide range of ventilatory support techniques available for anesthesia and critical care. In anesthesia, HFJV and HFPPV have been proved to be superior to conventional ventilation in ENT surgery, laryngoscopies, laser surgery, bronchoscopies, surgery of the upper airways, surgical resection of aneurysms involving the thoracic descending aorta, vocal cord surgery, microsurgery for superficial temporal artery to middle cerebral artery anastomosis and lithotripsy. In intensive care, HFJV and HFPPV offer some advantages over conventional ventilation with PEEP in the presence of acute respiratory failure with circulatory shock, acute ventricular failure, bronchopleural fistula with large airleak flows and tracheal lesions secondary to tracheostomy or prolonged intubation. In many other clinical situations HFJV and HFPPV have produced results identical with those obtained with conventional ventilation. Chronic obstructive pulmonary disease and asthma are absolute contra-indications to both techniques because overdistension and/or hypoventilation occur in the presence of increased respiratory compliance and/or elevated bronchial resistance. In unilateral lung disease HFJV and HFPPV offer no advantage over conventional ventilation.

Anesthesia↗
PubMed1989

Normovolemic hemodilution and lumbar epidural anesthesia.

This randomized study was designed to determine the cardiovascular effects of normovolemic hemodilution and lumbar epidural anesthesia in patients scheduled for vascular surgery. The patients were randomly assigned to three different groups: group 1 (N = 10) included patients undergoing lumbar epidural anesthesia without hemodilution; group 2 (N = 10) consisted of patients with normovolemic hemodilution without epidural anesthesia; and in group 3 (N = 10) normovolemic hemodilution was produced during lumbar epidural anesthesia. The three groups included several patients with a history of either myocardial infarction or stable mild angina or treated and controlled hypertension. In group 1, the level of epidural anesthesia reached T-9 +/- 1. After lumbar epidural anesthesia and 7 mL/kg colloid infusion, pulmonary capillary wedge pressure increased slightly but significantly above baseline, without significant changes either in mean arterial pressure or in cardiac index. In group 2, the same colloid infusion as in group 1 when infused before normovolemic hemodilution increased pulmonary capillary wedge pressure and cardiac index without significant effects on arterial blood pressure. Normovolemic hemodilution using a colloid solution decreased hemoglobin concentration (18%) and increased cardiac index significantly (9%). No significant change in systemic oxygen transport or in total body oxygen consumption was observed. In group 3, with anesthesia to T-9 +/- 1, hemodynamic changes were as observed in group 1. After normovolemic hemodilution, hemoglobin concentration decreased significantly (15%), whereas cardiac index increased significantly (15%) without significant changes either in mean arterial pressure or in heart rate. Systemic oxygen transport and total body oxygen consumption did not change significantly. No patient experienced chest pain or electrocardiographic evidence of myocardial ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Epidural↗
PubMed1988

Improvement of diaphragmatic function by a thoracic extradural block after upper abdominal surgery.

The effects on diaphragmatic function of a thoracic epidural block were assessed in 13 patients after upper abdominal surgery (UAS). Lung volumes and tidal changes in chest wall circumferences and gastric (delta Pgas) and esophageal (delta Pes) pressures were measured pre- and postoperatively. Volume displacement of the abdomen divided by tidal volume (delta VAB/VT) and delta Pgas/delta Pes were taken as indices of the diaphragmatic contribution to tidal breathing. These respiratory variables were obtained in the postoperative period, before and after epidural injection of 0.5% plain bupivacaine to achieve a block up to the T4 segment. UAS was constantly associated with a decrease in VT, delta VAB/VT, delta Pgas/delta Pes, and forced vital capacity (FVC). Epidural block was associated with an increase in VT, delta VAB/VT, and FVC. delta Pgas and delta Pgas/delta Pes returned to their preoperative values. It is concluded that: 1) diaphragmatic dysfunction observed after UAS is partially reversed by thoracic epidural block; and 2) that inhibitory reflexes of phrenic activity arising from the abdominal compartment (abdominal wall and/or viscera) could be involved in this diaphragmatic dysfunction.

Abdomen↗
PubMed1988

The influence of position on ventilation-perfusion distribution after abdominal surgery.

The effects of a change in position on gas exchange and ventilation perfusion (VA/Q) distribution were studied in 12 patients, after abdominal surgery. VA/Q distribution was determined from retention and excretion curves of six inert gases of different solubilities, in supine and sitting patients, during spontaneous breathing. Changing position from supine to sitting resulted in an increase in minute ventilation and a decrease in PaCO2 without any change in PaO2. With regard to VA/Q distribution, an estimated shunt of 5.2% +/- 3.4 was documented in all the patients in the supine position, and was associated with a large percentage of low VA/Q regions (20.0% +/- 13.0) in six of them. Patients with associated estimated shunt and low VA/Q regions were those with the greatest amount of venous admixture (respectively: 27.3% +/- 7.2, and 14.9% +/- 3.0, for patients without low VA/Q regions, P less than 0.01). When patients were placed in the sitting position, the estimated shunt was not reduced, but the percentage of low VA/Q regions decreased when it was documented. Despite the improvement of VA/Q distribution in the sitting position, the lack of significant change in PaO2 may be explained by the simultaneous decrease in PVO2 caused by a decrease in cardiac output.

Adult↗
PubMed1988

Prehospital autotransfusion in life-threatening hemothorax.

Eighteen patients with life-threatening traumatic hemothorax received prehospital autotransfusion using a simple new device. During transfer to the hospital, they received 3.9 +/- 0.5 L of colloid fluid and 4.1 +/- 0.6 L of autotransfused blood, without anticoagulation. Hemorrhagic blood was not coagulable, had a hematocrit of 20 +/- 4 percent, few platelets, and low fibrinogen levels. Five patients died from irreversible hemorrhagic shock. Thirteen patients were alive upon admission to the hospital, underwent emergency surgery, and were discharged alive. During autotransfusion, hematocrit decreased from 24 +/- 3 to 19 +/- 3 percent, and systolic arterial pressure increased from 78 +/- 11 to 88 +/- 12 mm Hg. Upon admission to the hospital, platelet count was 90,800 +/- 21,400/cu mm, prothrombin time 48 +/- 3 percent, partial thromboplastin time 197 +/- 18 percent, plasma free hemoglobin levels 21 +/- 7 mg/100 ml, and serum potassium levels 3.6 +/- 0.5 mmol/L. No serious complication could be related to autotransfusion considered to be crucial to patients' survival. The preliminary results of this study suggest that autotransfusion might be developed in the prehospital setting since it appears simple and safe, and represents the only hope of survival for patients with life-threatening hemothorax.

Blood Transfusion, Autologous↗