Effect of resistive loads on pattern of respiratory muscle recruitment during exercise.

In healthy subjects, we compared the effects of an expiratory (ERL) and an inspiratory (IRL) resistive load (6 cmH2O.l-1.s) with no added resistive load on the pattern of respiratory muscle recruitment during exercise. Fifteen male subjects performed three exercise tests at 40% of maximum O2 uptake: 1) with no-added-resistive load (control), 2) with ERL, and 3) with IRL. In all subjects, we measured breathing pattern and mouth occlusion pressure (P0.1) from the 3rd min of exercise, in 10 subjects O2 uptake (VO2), CO2 output (VCO2), and respiratory exchange ratio (R), and in 5 subjects we measured gastric (Pga), pleural (Ppl), and transdiaphragmatic (Pdi) pressures. Both ERL and IRL induced a high increase of P0.1 and a decrease of minute ventilation. ERL induced a prolongation of expiratory time with a reduction of inspiratory time (TI), mean expiratory flow, and ratio of inspiratory to total time of the respiratory cycle (TI/TT). IRL induced a prolongation of TI with a decrease of mean inspiratory flow and an increase of tidal volume and TI/TT. With ERL, in two subjects, Pga increased and Ppl decreased more during inspiration than during control suggesting that the diaphragm was the most active muscle. In one subject, the increases of Ppl and Pga were weak; thus Pdi increased very little. In the two other subjects, Ppl decreased more during inspiration but Pga also decreased, leading to a decrease of Pdi. This suggests a recruitment of abdominal muscles during expiration and of accessory and intercostal muscles during inspiration. With IRL, in all subjects, Ppl again decreased more, Pga began to decrease until 40% of TI and then increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Preoperative nutritional evaluation of elderly patients: the Mini Nutritional Assessment as a practical tool.

BACKGROUND AND GOAL: Age and malnutrition are each surgical risk factors. Because the Mini Nutritional Assessment (MNA) has been specifically designed for assessing the nutritional status of elderly patients, it can be used for preoperative nutritional evaluation. Therefore, the MNA was included in the preoperative clinical evaluation of patients over 60 years of age to describe their nutritional status. METHODS: Every patient over 60 years of age, scheduled for elective surgery, was seen in anaesthesiology consultation and was submitted to the MNA. The MNA is a clinical score consisting of four additive items: 'Anthropometric assessment' based on BMI, mid-arm and calf circumferences, weight loss; global evaluation; dietetic assessment, and subjective assessment - these last three items being obtained through a specific questionnaire. It requires no biological marker. Awarding to the obtained score, the MNA stratifies patients in the following categories: well-nourished (24

[X-ray computed tomography in mediastinal lymph node tuberculosis. Apropos of 3 cases]. / L'apport de la TDM dans la tuberculose ganglionnaire médiastinale. A propos de 3 observations.

About three cases of isolated mediastinal nodal tuberculosis--one of them leading to an erroneous diagnosis--the authors try to evaluate the semiologic criteria of this disease by C.T. scan.

[Delay of clinical recovery from paralysis induced by atracurium: comparison between orbicularis oculi and adductor pollicis]. / Délai de récupération clinique d'une paralysie induite par l'atracurium: comparaison entre orbiculaire des paupières et adducteur du pouce.

OBJECTIVE: To compare with train-of-four stimulation the delays of the beginning of the spontaneous recovery of the orbicularis oculi and of the adductor pollicis after profound neuromuscular blockade with atracurium. STUDY DESIGN: Prospective, comparative open study. PATIENTS AND METHODS: Twenty-eight physical class ASA 1 and 2 patients under general anaesthesia (propofol, N2O, fentanyl) and profound neuromuscular blockade with atracurium. Train-of-four stimulation, every 10 s, of the ulnar nerve at the wrist (for assessing by tactile means the response of the adductor pollicis) and of the temporal branch of the facial nerve (for assessing visually the response of the orbicularis oculi). On each site, measurement of the delay between the end of the maintenance of deep neuromuscular blockade (last dose of atracurium) and the beginning of the recovery (first response to train-of-four stimulation). RESULTS: In each case, the recovery of the orbicularis oculi began earlier than the recovery of the adductor pollicis (26 +/- 9 min vs 34 +/- 9 min, P < 0.001). The delays of recovery at each site were strongly correlated (r = 0.87; P < 0.001) but the time lag between the responses varied greatly: 1 to 21 min, mean: 8 +/- 5 min, coefficient of variation: 56.6%. CONCLUSION: The orbicularis oculi should not be monitored alone for assessment of recovery from profound neuromuscular blockade by atracurium, as it predicts poorly the time of the recovery of the adductor pollicis.

[Pregnancy and asthma]. / Grossesse et asthme.

One in a hundred pregnant females has asthma. Pregnancy may change the course of the asthma and inversely foetal and obstetric prognosis may be affected by the illness and by the potentially deleterious effect of treatment. The maternal physiological changes which occur during pregnancy throw little light on the variations in asthma during pregnancy. Clinical studies in the literature suggest that the quality of follow-up and treatment in patients allows for a satisfactory outcome in pregnancy and that it is an important prognostic factor. Overall, taking account of the pregnancy and confinement the therapeutic approach of the thoracic physician differs little from that in management outside pregnancy. The first objective is to relieve the bronchial obstruction. Broncho-dilator therapy with beta-agonist and by theophylline remains usable in most cases. The side effects of steroid therapy ought to be balanced against the advantages, in order to maintain a normal physiological state. Immunotherapy, and antibiotics should be adapted appropriately for the pregnancy and for their respective contra-indications. Finally, the prevention of atopy should be envisaged.

[Pressure-controlled mechanical ventilation: a simplified titration method of the extrinsic positive expiratory pressure]. / Ventilation mécanique en pression contrôlée: une méthode simplifiée de titration de la pression expiratoire positive extrinsèque.

OBJECTIVES: Extrinsic positive end-expiratory pressure (PEEPe) may improve gas distribution within the lungs, induce alveolar recruitment or, conversely, produce pulmonary overdistension, and modify the respiratory impedance. Under pressure-controlled mechanical ventilation (PCV) this phenomenon modifies the minute ventilation and the dynamic compliance of the respiratory system (Crs,dyn). This study was aimed to assess the incidence of a significant gain in Crs,dyn under the effect of PEEPe during PCV. STUDY DESIGN: Prospective, open, descriptive, case series study. PATIENTS: Surgical intensive care unit patients, under sedation, neuromuscular blockade and PCV because of severe hypoxaemia (ARDS or acute lung injury). METHODS: Four incremental levels of PEEPe (4 to 16 cmH2O) of 30 minute duration were applied. Crs,dyn, and PaO2/FIO2 were recorded at the end of each level of PEEPe. The resulting gain in Crs,dyn was calculated and considered as significant if it was greater than the upper limit of confidence (at 99.8%) of the statistical distribution of all the recorded gains. RESULTS: Thirty patients were included, median and extreme values (within brackets) of PaO2/FIO2 of 117 [53-230] and Crs,dyn without PEEPe of 29 [14.3-46.8] mL.cmH2O-1. Among the 120 recorded gains, a gain in Crs,dyn was found significant at least once in 15 tests of PEEPe out of 30. Within the two groups of patients, the increase in PaO2/FIO2 with incremental PEEPe was similar. The levels of PEEPe producing the greatest increase in Crs,dyn were not correlated with the increase in PaO2/FIO2. CONCLUSION: In 50% of the studied patients a significant gain in Crs,dyn was found, allowing a less traumatic PCV. These results suggest the clinical usefulness of this method of titration of PEEPe, which requires neither specific devices nor a disconnection of the patient.

[Anesthesia and obesity]. / Anesthésie et obésité

Problems encountered during anesthesia procedures in obese subjects is related to the level of overweight. Obesity multiplies the effect of general anesthesia on the respiratory function and increases the postoperative risk of cardiovascular disorders and deep vein thrombosis. The pharmacokinetic behavior of most general anesthesia drugs is affected by the mass of adipose tissue producing a prolonged less predictable effect. Control of airway permeability and continence is also a major problem with predictable or unpredictable difficulties with endotracheal intubation. Locoregional anesthesia, which avoids the intubation problem, is difficult to implement and does not provide satisfactory results in all cases. The preoperative work-up should assess the consequences of obesity, particularly concerning the respiratory, cardiovascular, and metabolic systems. A proper work-up allows the anesthesist to provide the obese subject with well-informed information on the risk and benefit of proposed options.

[Respiratory risk of general surgery in adults]. / Le risque respiratoire en chirurgie générale chez l'adulte.

Disorders of ventilation and postoperative bronchial and pulmonary infections still create serious problems in general surgery. Three factors determine these complications: (1) the transient and usually resolutive repercussions of anaesthesia on ventilation; (2) the sometimes deep and prolonged alteration of lung function directly due to the surgical procedure, and (3) the patient's underlying condition. In practice, this last group of surgical patients can be divided into fragile subjects (elderly people, pregnant women), subjects at risk (smokers, malnourished or obese patients) and disabled subjects suffering from chronic obstructive or restrictive lung disease, asthma or heart disease. Preoperative clinical, radiological and, chiefly, functional evaluation leads to preventive measures. Preparation for surgery relies, to a great extent, on respiratory physiotherapy which, if needed, may be integrated in a pneumological therapeutic program. Combined with an efficient postoperative analgesia and with an optional anaesthesia technique, respiratory physiotherapy is essential to the prevention of respiratory complications in surgery.

[Impact of Express study on clinical practice in ARDS patients: a single French ICU experience]. / Evolution des pratiques ventilatoires chez les patients en SDRA lors de la participation à un essai clinique randomisé: l'expérience d'une unité de réanimation française.

INTRODUCTION: The French Express study compared two alveolar recruitment managements (maximal versus standard) in Acute Respiratory Distress Syndrome (ARDS) patients ventilated with 6 ml/kg of ideal body weight (IBW). The objective of the present study was to assess in a single intensive care unit, the impact of Express study on the mechanical ventilation settings in non-included ARDS patients. PATIENTS AND METHODS: From 16 October 2002 to 14 January 2005 all consecutive eligible but non-included patients in Express study were studied. The maximal and minimal tidal volumes, and the minimal and maximal respiratory rates were retrospectively recorded. These parameters were compared according to the date of patient's admission and then the patients were separated in four quartiles (14, 15, 15, 15 patients). RESULTS: From the first to the last study period separated by 26 months, the mean maximal tidal volume decreased from 9.0+/-1.3 to 7.4+/-1.0 ml/kg of IBW (p=0.03), the proportion of patients ventilated with a maximal tidal volume greater than 8 ml/kg decreased from 93% to 20% (p<0.01), the median minimal respiratory rate increased from 14 to 18 b/min (p=0.03) and the proportion of patients with a respiratory rate less than 20 b/min decreased from 100% to 73% (p<0.01). There were correlations between the time of patient's admission and the maximal tidal volume (r=-0.43, p<0.01), the minimal tidal volume (r=-0.28, p<0.04) and the minimal respiratory rate (r=0.33, p<0.02). CONCLUSION: The participation in Express study led physicians to modify their mechanical ventilation settings. The maximal tidal volume decreased and the minimal respiratory rate increased in the ARDS eligible but non-included patients.

[Pulmonary and systemic vascular effects of ATP in man]. / Effets vasculaires pulmonaires et systémiques de l'ATP chez l'Homme.

ATP induced-vasodilation was studied using Striadyne, on pulmonary and systemic arterial bed on 10 patients with stable chronic obstructive pulmonary disease. Such significant effects varied according to the dose: pulmonary vasodilation reached maximal level during low rate infusion (2 mumoles/kg/20 min) and systemic vasodilation was related to the dose. The latter became dominant at maximal dose (5 mumoles/kg/20 min). Simultaneously, on four patients, circulating blood level of ATP was assessed. It increased in proportion with the infusion rate and reached respectively 167% and 149 of baseline level on arterial and mixed venous blood.

The effect of positive end-expiratory pressure on respiratory resistive properties in anaesthetized paralysed humans.

The respiratory resistive properties of the normal human respiratory system are volume-dependent. The overall flow resistance (Rmax,rs) can be partitioned into airway resistance (Raw) and the additional resistance (delta Rrs) which may result from the viscoelastic properties of the respiratory system, from inequality of time constants (pendelluft), or from both. Because positive end-expiratory pressure (PEEP) increases end-expiratory lung volume and may equalize ventilation within the lungs, the effect of PEEP on Raw, delta Rrs, and their sum (Rmax,rs) was assessed in anaesthetized surgical patients without evidence of lung disease. Fifteen men were studied during paralysis and isoflow isovolume mechanical ventilation, using the end-inflation occlusion method. Ten men were studied with incremental levels of PEEP, up to 16 cmH2O (Group A). Five men were studied without PEEP (Group B). In Group A, Rmax,rs did not change with PEEP. In contrast, Raw decreased and delta Rrs increased significantly. Moreover, there was a linear relationship between PEEP and the contribution of delta Rrs to Rmax,rs. In Group B, Rmax,rs, Raw and delta Rrs, and the contribution of delta Rrs to Rmax,rs did not change. In both groups, atropine elicited a decrease in Rmax,rs, linked to a decrease in Raw, without any notable effect on the static elastance of the respiratory system (Est,rs) or on delta Rrs. We conclude that the overall flow resistance was not affected by PEEP. In contrast, PEEP clearly modified the contribution of its two components. The decrease in Raw with PEEP could have resulted, at least in part, from modification in the basal vagal tone.

The Mini Nutritional Assessment-Short Form for preoperative nutritional evaluation of elderly patients.

The Mini Nutritional Assessment (MNA) is a clinical tool designed for assessing nutritional status of elderly patients. Used in preoperative evaluation of ambulatory patients over 60 years of age seen on anesthesia consultation in a previous study, it identified 6.9% patients with overt malnutrition out of a group of 408. However, four-fifths of 291 ASA 1-2 patients were well nourished, and underwent needless, non-contributory and time-consuming test. The MNA-Short Form (MNA-SF) has recently been devised as the first step of a two-step process: if negative, there would be no need to complete "full" MNA. Therefore, the base data of 408 MNA forms completed during the above-mentioned study was used for the purpose of comparing the MNA-SF to the MNA, to test whether the MNA-SF could have been the first step of a two-step nutritional evaluation of anesthesia patients. Median (range) age, and BMI were 72 (60-98) years, and 25.2 (12.8-40.4) kg x m(-2), respectively. There were equal numbers of men and women. In 144 cases, the MNA-SF was found positive (35.3%) with a median MNA of 21.5 (1.5-27) points. The MNA-SF predicted absence of overt malnutrition revealed by the MNA, with 100% sensitivity and negative predictive value (NPV). It was found less efficient for predicting absence of "possible" nutritional problems detected by the MNA (sensitivity 85.6% and NPV 92.8%). However, none of the 19 borderline patients would have had overt malnutrition, being only found "at risk of malnutrition" by the MNA. On the studied sample, the MNA-SF would have correctly sorted out 69.5% of the patients without severe malnutrition. We believe the MNA-SF should be used as the first step of an efficient preoperative nutritional evaluation of ambulatory elderly patients.