Biomedical subjects
F Héritier
Publications and source records attributed to F Héritier.
[Antibiotics in aerosols].
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[Evaluation of the inspiratory muscle strength using the nasal pressure of the sniff].
The measurement of oesophageal pressure during maximal sniffs (Poes sniff) is useful to assess inspiratory muscle strength. The aim of this study was to develop a noninvasive test of inspiratory muscle strength based on the sniff manoeuvre. The sniff nasal inspiratory pressure (SNIP) was measured through a plug occluding one nostril during sniffs performed through the contralateral nostril. In 10 normal subjects and in 12 patients with neuromuscular or skeletal disorders, the SNIP reliably reflected the Poes sniff. Nasal mucosa congestion was induced in four normal subjects by nebulization of increasing doses of histamine. The SNIP accurately reflected Poes sniff when nasal congestion was moderate, but failed to do so when congestion was severe. Reference values of SNIP were established in a group of 160 healthy subjects aged 20-80 years. For both men and women, SNIP was negatively correlated with age, and was similar in the sitting and in the supine positions. SNIP was higher than maximal inspiratory pressure (P1 max) in most subjects, but the wide limits of agreement showed that these two methods are not interchangeable but complementary. The SNIP represents a useful noninvasive test of inspiratory muscle strength.
Sniff nasal inspiratory pressure. A noninvasive assessment of inspiratory muscle strength.
The measurement of esophageal pressure during maximal sniffs (sniff Pes) has been shown useful to assess inspiratory muscle strength. The aim of this study was to validate a noninvasive method for estimating sniff Pes. The sniff nasal inspiratory pressure (SNIP) was measured through a plug occluding one nostril during sniffs performed through the contralateral nostril. Sniff Pes was simultaneously measured with an esophageal balloon. Ten normal subjects performed 338 sniffs of variable intensity. The correlation coefficient of SNIP and sniff Pes was 0.99 +/- 0.01 (p < 0.001). The ratio SNIP/sniff Pes was 0.91 (range, 0.82 to 0.99) and the mean difference between the two measures (SNIP - sniff Pes) was -4.56 cm H2O (-1.2 to -8.6 cm H2O). Twelve patients with neuromuscular or skeletal disorders performed 181 maximal sniffs. The correlation coefficient of SNIP and sniff Pes was 0.96 +/- 0.04 (p < 0.001). The ratio SNIP/sniff Pes was 0.93 (0.77 to 1.07) and the mean difference (SNIP - sniff Pes) was -4.66 cm H2O (+0.47 to -14.26 cm H2O). Nasal mucosal congestion was induced by nebulization of increasing doses of histamine in four normal subjects. The ratio SNIP/sniff Pes was 0.93 (0.72 to 1.02) when nasal peak flow was > 100 L/min, and 0.49 (0.36 to 0.57 L/min) when nasal peak flow fell below 100 L/min. We conclude that SNIP provides a reliable and noninvasive estimation of sniff Pes in normal subjects and in patients with neuromuscular or skeletal disorders. The validity of this method may by impaired by severe nasal congestion.
[Diving: physical and physiological bases].
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[Heart-lung transplantation, single lung and both lungs].
Following the improvement in surgical techniques and immunosuppression regimens as well as a better selection of recipients, an increasing number of heart-lung, single lung and double lung transplantations have been performed within the last decade. In the early stages, most candidates had advanced pulmonary hypertension. More recently, patients with end-stage lung disease have been successfully transplanted. Providing the allografts remain free of complications, long-term survivors may benefit of well preserved pulmonary function. However, acute rejection, obliterative bronchiolitis and infections are still a major cause of morbidity and mortality.
[Scuba diving: barotrauma, decompression sickness, pulmonary contra-indications].
The practice of scuba diving is associated with two specific medical problems: barotrauma directly related to changes in ambient pressure, and decompression sickness related to the uptake and the release of inert gases by the body. Neurological symptoms are frequent in severe diving accidents. They may arise following either barotrauma or decompression sickness, and often require urgent treatment in a hyperbaric chamber. Asthma, chronic obstructive pulmonary disease, and spontaneous pneumothorax increase the risk of lung barotrauma and represent contraindications to diving.
[Adenocarcinoma of the ovary as a study model of cancers and their treatments].
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[The pulmonary manifestations of diving accidents].
Scuba diving is associated with risks of drowning, lung barotrauma and decompression sickness. In case of near-drowning, irreversible neurologic lesions or death may follow an acute hypoxemia or a cardiopulmonary arrest. Therefore, victims of drowning should benefit from an immediate and prolonged cardiopulmonary resuscitation. Lung barotrauma are due to the failure of expanding lung gases to escape during ascent; they are likely to be complicated by arterial gas embolism. They can follow a panic ascent even from a shallow depth. Most of decompression procedures induce the formation of asymptomatic venous gas bubbles, normally filtrated and eliminated by the lungs. In case of massive intravenous bubbling, the filtering capacity of the lungs can be overwhelmed and the lung microcirculation damaged up to the point of provoking a cardio-respiratory failure.
[Neuroradiological studies in diving accidents].
In case of a type II decompression sickness (with cerebrospinal injury), the decision on how to structure a prompt hyperbaric treatment rests on an anamnesis and the clinical investigation. In looking for an associated contingent barotrauma, one has to be satisfied with an X-ray of thorax and abdomen. The myelopathy which results from a decompression mishap with medullary involvement forms a very peculiar clinical entity defined by a fascicular injury at several levels. For several years now, clinical radiologists resort to a new medical imaging technique: Nuclear Magnetic Resonance (NMR-)Imaging. For the first time, this technique allows the imaging of intramedullary lesions due to a decompression accident. Other neuroradiological investigations (such as myelography, spinal tomodensitometry, medullary angiography, isotopic tests) are without merit for evaluating decompression accidents with medullary involvement. NMR-Imaging has the potential too, of revealing ischemic cerebral injuries, even if the clinical brain impairment is often silent and therefore overlooked. The role of NMR-Imaging for evaluating cerebrospinal aspect of decompression accidents is not yet finalized. However, NMR-Imaging will give without any doubt a boost to the pathophysiological knowledge of decompression mishaps.
Lung allograft transplantation: indications, preoperative assessment and postoperative management.
In spite of a shortage of available donors, an increasing number of heart-lung transplantations have been performed within the last decade. This procedure, first limited to patients with pulmonary vascular disease, has been successfully extended to patients with end stage lung disease, including cystic fibrosis. More recently, single lung, double-lung and bilateral single lung transplantation have become other therapeutic options. Better selection of patients and donors as well as improvements in surgical techniques and immunosuppression regimens have contributed to the reduction in the high perioperative mortality experienced in the early stages. Moreover, the introduction of daily spirometry and transbronchial lung biopsies have permitted early and reliable diagnosis of opportunistic infection and rejection. The most serious late complication of lung transplantation is obliterative bronchiolitis and further research is urgently required to improve diagnosis and management of this condition.
Esophageal and mouth pressure during sniffs with and without nasal occlusion.
The sniff maneuver has recently been advocated for assessing inspiratory muscle strength. We characterized the relationship between mouth pressure (Pmo) and esophageal pressure (Pes) during sniffs performed with open, semi-occluded, and occluded nose. In seven normal subjects, pressure was simultaneously measured with a mouthpiece (Pmo) an esophageal balloon (Pes) during high- and low-intensity sniffs performed from FRC. With open nose, the mean ratio Pmo/Pes was 0.96 +/- 0.05 (mean +/- SE). The mean ratio Pmo/Pes was not significantly different in high- and low-intensity sniffs. With one nostril occluded, the mean ratio Pmo/Pes was 1.03 +/- 0.04. The ratio Pmo/Pes was significantly higher than with open nose for all sniffs (P less than 0.05) and low-intensity sniffs (P less than 0.01). With both nostrils occluded, the mean ratio Pmo/Pes was 1.06 +/- 0.03, with occasional marked overestimation of Pes by Pmo. We conclude that Pmo generally reflects Pes during sniffs performed with open and semi-occluded nose, but not with complete nasal occlusion.
[Programmed autologous transfusion in coronary surgery: experience with 106 patients].
Patients undergoing elective coronary bypass surgery can benefit from Preoperative Autologous Blood Donation (PAB), despite some opinions to the contrary, as a complement of intra-operative blood salvage techniques. We report herein 106 patients eligible for coronary bypass surgery included in our PAB program. We observed a very good tolerance owing to strict exclusion criteria, a close monitoring of vital signs, and as far as we are concerned, to the infusion of a macromolecular solution (Plasmion) in a 1:1 ratio, to maintain intra-vascular volume. We chose a volume replacement because the physiological adaptation to hypovolemia is altered by the beta-blocking and/or vasodilating agents which cannot be discontinued in patients with coronary heart disease. The changes in the hematological parameters are not different from those observed in other patients eligible for PAB. The postoperative hemoglobin level is satisfactory and compatible with a normal myocardial function inasmuch as the cardiopathy has been corrected. The efficiency of PAB is good since overall, 74% of the patients did not require homologous blood, this proportion rises to 84% for patients donating 3 or more units. Preoperative Autologous Blood Donation for patients with coronary heart disease implies a perfect coordination between the Blood Bank physicians and their colleagues from the Cardiology Department. Aside from its well known advantages, PAB allows a stimulation of erythropoiesis, a progressive normovolemic hemodilution perhaps beneficial to patients with coronary heart disease, and finally, a better psychological preparation to surgery.
Maximal sniff mouth pressure compared with maximal inspiratory pressure in acute respiratory failure.
Inspiratory muscle strength most often is better reflected by sniff Pes than PImax against occlusion. Furthermore, sniff Pes can be estimated noninvasively by the measurement of sniff Pmo in normal subjects and in patients with respiratory muscle weakness. The aim of this study was to compare sniff Pmo and P.PImax to assess inspiratory muscle strength in patients with acute respiratory failure. The highest pressure was produced by P.PImax in 61 percent of measurements, and by sniff Pmo in 39 percent. Above 35 cm H2O P.PImax yielded the highest pressure in 55 percent of cases and the ratio sniff Pmo/P.PImax was 1.20 +/- 0.54. Below 35 cm H2O, P.PImax yielded the highest pressure in 75 percent of cases and the ratio sniff Pmo/P.PImax was 0.76 +/- 0.35 (p less than 0.02). Thus, measurements of sniff Pmo and P.PImax complement one another for assessing inspiratory muscle strength. However, sniff Pmo underestimates inspiratory muscle strength in patients with severe inspiratory muscle weakness.
[Barotrauma and decompression illness: diagnosis and adjuvant medical treatment in recompression].
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