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Biomedical subjects

P Barriot

Publications and source records attributed to P Barriot.

18 recordsLinked to original sources

[Endotracheal intubation under propofol with or without vecuronium].

OBJECTIVE: In order to test the hypothesis that under the association propofol-alfentanil-IV lidocaine the trachea could be intubated easily without an additional muscle relaxant, this study compared the intubation conditions when this association was combined or not with vecuronium. STUDY DESIGN: Randomized comparative trial. PATIENTS: The study included 152 young adults classified as ASA physical class I and Mallampati presentation grade 1, randomly allocated either into Vecu+ group or Vécu0 group, depending on whether vecuronium was co-administered or not. METHODS: All patients received midazolam 0.05 mg.kg-1 i.v., one minute before induction. Those of group Vecu0 were given successively within two minutes: alfentanil 0.03 mg.kg-1, lidocaine 1.5 mg.kg-1 i.v. and propofol 2.5 mg.kg-1. Patients of group Vecu+ received similar doses of alfentanil and propofol as well as vecuronium 0.08 mg.kg-1. The endotracheal tube was inserted one minute after induction in the patients of Vecu0 group, and after three minutes in those of the Vecu+ group. During intubation, scores of mouth opening, glottis opening and coughing were established, in order to assess intubation conditions. RESULTS: Similar convenient intubating conditions were obtained in both groups (in 97% of patients in Vecu+ group vs 95% of those in Vecu0 group). In the latter, the glottis opening was less pronounced. CONCLUSIONS: In young healthy adults, without anaesthetic risk (emergency, full stomach) and without foreseen difficult intubation, the endotracheal tube can be inserted in convenient conditions without a muscle relaxant, under the association propofol-alfentanil-lidocaine iv.

Adult

[Severe accidental hypothermia].

Two cases of severe accidental hypothermia (core temperature below 25 degrees C) are reported. Both occurred in an urban area during the same winter period. Both patients had the same age and similar clinical symptoms. In the first patient, the EEG, the echocardiography and the blood gases were in favour of a good tolerance of hypothermia, which led to choice a non aggressive rewarming method. The latter included the rewarming of inhaled gas mixture as well as i.v. fluids and gastro-intestinal lavage fluid. The outcome was uneventful. In the second patient, the visceral and biological consequences were more important (pH: 6.80, blood glucose concentration: 1.48 mmol.L-1, major coagulation disorders). Therefore a rapid rewarming via a cardiopulmonary bypass was preferred. The patient died from a prolonged shock with disseminated intravascular coagulation. The use of cardiopulmonary bypass which is essential in case of cardiac arrest rhythm, is controversial in case of severe hypothermia with a still beating heart.

Acidosis

Elevated blood cyanide concentrations in victims of smoke inhalation.

BACKGROUND: The nature of the toxic gases that cause death from smoke inhalation is not known. In addition to carbon monoxide, hydrogen cyanide may be responsible, but its role is uncertain, because blood cyanide concentrations are often measured only long after exposure. METHODS: We measured cyanide concentrations in blood samples obtained at the scene of residential fires from 109 fire victims before they received any treatment. We compared the results with those in 114 persons with drug intoxication (40 subjects), carbon monoxide intoxication (29 subjects), or trauma (45 subjects). The metabolic effect of smoke inhalation was assessed by measuring plasma lactate at the time of admission to the hospital in 39 patients who did not have severe burns. RESULTS: The mean (+/-SD) blood cyanide concentrations in the 66 surviving fire victims (21.6 +/- 36.4 mumol per liter, P less than 0.001) and the 43 victims who died (116.4 +/- 89.6 mumol per liter, P less than 0.001) were significantly higher than those in the 114 control subjects (5.0 +/- 5.5 mumol per liter). Among the 43 victims who died, the blood cyanide concentrations were above 40 mumol per liter in 32 (74 percent), and above 100 mumol per liter in 20 of these (46 percent). There was a significant correlation between blood cyanide and carbon monoxide concentrations in the fire victims (P less than 0.001). Plasma lactate concentrations at the time of hospital admission correlated more closely with blood cyanide concentrations than with blood carbon monoxide concentrations. Plasma lactate concentrations above 10 mmol per liter were a sensitive indicator of cyanide intoxication, as defined by the presence of a blood cyanide concentration above 40 mumol per liter. CONCLUSIONS: Residential fires may cause cyanide poisoning. At the time of a patient's hospital admission, an elevated plasma lactate concentration is a useful indicator of cyanide toxicity in fire victims who do not have severe burns.

Adolescent

Diazepam does not improve the mechanical performance of rat cardiac papillary muscle exposed to chloroquine in vitro.

Diazepam has been reported to decrease the cardiac toxicity of chloroquine but the precise mechanism involved remains unknown. Left ventricular papillary muscles from adult Wistar rats were exposed to 10(-4) M chloroquine and assigned to three groups: group I (n = 10) exposed to chloroquine alone; group II (n = 8) exposed to chloroquine and 10(-5) M diazepam; group III (n = 8) exposed to chloroquine and 10(-4) M diazepam. The main mechanical parameters measured were: maximum unloaded shortening velocity (Vmax), maximum lengthening velocity (maxVr), active force normalized per cross-sectional area (AF/s), contraction-relaxation coupling under low load (R1), load sensitivity of relaxation (Isot.A/Isom.A), and peak power output (Emax) determined from Hill's equation of the force-velocity curve. Data are expressed as mean percent of control values +/- SD, for groups I, II, III respectively. No differences between groups I, II, and III were noted for Vmax (87 +/- 13, 82 +/- 9, 86 +/- 7), maxVr (47 +/- 6, 48 +/- 11, 52 +/- 11), AF/s (87 +/- 16, 91 +/- 10, 83 +/- 11), Isot. A/Isom. A (113 +/- 9, 108 +/- 3, 109 +/- 7), or Emax (75 +/- 10, 81 +/- 12, 72 +/- 16). Chloroquine was shown to be a negative inotropic agent since it decreased Vmax, AF/s and Emax, but diazepam did not restore the intrinsic mechanical performance of rat cardiac papillary muscle exposed to chloroquine, therefore 1) the protective cardiovascular effects of diazepam in chloroquine poisoning are not related to an improvement in intrinsic cardiac mechanical properties; 2) inotropic agents are therefore necessary in combination with diazepam for the treatment of severe chloroquine poisoning.

Animals

[Intravenous thrombolysis with tissue plasminogen activator (rt-PA) at the prehospital phase of acute myocardial infarction. Apropos of 49 cases].

In acute myocardial infarction, the earlier intravenous thrombolysis is performed the more effective its action. Pre-hospital intravenous thrombolysis with 100 mg rt-PA was carried out in 49 patients within 3 hours of myocardial infarction. Male preponderance was conspicuous with 44 men (92%) and only 5 women (8%). Mean age was 50.2 +/- 8 years. The infarction was inferior in 48% of the cases. Out of the 49 thrombolyses performed by the mobile intensive care unit, 3 were discontinued on admission (2 diagnostic errors, 1 external heart massage). The time gained by pre-hospital thrombolysis was 52 +/- 25 minutes. There were few complications of thrombolysis: blood effusion at the site of puncture occurred in 4 cases (9%) and haematemesis in 1 case (2%). No cerebral or lethal haemorrhage was observed. Major complications of MI were seldom encountered at the pre-hospital phase: 1 patient died of extensive anterior necrosis with left ventricular dysfunction, and 2 had reversible ventricular fibrillation before treatment was initiated. There was no haemorrhagic complication. The earlier the patient was treated the lower the mortality and morbidity rates. Pre-hospital thrombolysis therefore seems to be feasible when performed by a mobile intensive care unit, and it represents an important gain of time.

Adult

Treatment of severe chloroquine poisoning.

No therapy has been proved to be effective for patients with severe chloroquine poisoning, which is usually fatal. In a retrospective study of 51 cases, we found that ingestion of more than 5 g of chloroquine was an accurate predictor of a fatal outcome, and therefore chose this dose as the criterion for severe chloroquine poisoning. We selected as a control group 11 consecutive patients who had ingested more than 5 g of chloroquine between July 1983 and December 1985. We then undertook a prospective study to determine whether a better outcome could be obtained with immediate mechanical ventilation and the administration of diazepam and epinephrine. Eleven consecutive patients who ingested more than 5 g of chloroquine in 1986 received this combination therapy. Ten of these patients survived, whereas only one control had survived (P = 0.0003). There was no significant difference between the combination-therapy and control groups in age (29 +/- 3 vs. 27 +/- 2 years), amount of chloroquine ingested (7.5 +/- 0.5 vs. 8.5 +/- 0.8 g), systolic arterial pressure (74 +/- 2 vs. 74 +/- 3 mm Hg), or QRS duration (0.14 +/- 0.01 vs. 0.14 +/- 0.01 second). In our combination-therapy group, blood chloroquine levels ranged from 40 to 80 mumol per liter, whereas a literature search showed that no patient in whom blood levels were more than 25 mumol per liter had survived. These preliminary data suggest that combining early mechanical ventilation with the administration of diazepam and epinephrine may be effective in the treatment of severe chloroquine poisoning.

Adolescent

Retrograde technique for tracheal intubation in trauma patients.

Nineteen trauma patients with either maxillofacial trauma or cervical spine fracture were orotracheally intubated over a guidewire percutaneously inserted through the cricothyroid membrane into the mouth in a retrograde fashion. In 13 patients, conventional techniques failed (average number of attempts 6 +/- 1, mean duration 18 +/- 1 min); in six patients, the initial method of choice was a retrograde technique. In all patients, retrograde technique succeeded on only one attempt (duration less than 5 min in all cases). No serious complication could be related to this technique; it is an easy, safe, efficacious method for difficult tracheal intubation in trauma patients.

Adult

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

[Fatal asthma].

Fatal asthma is rare but constitutes a serious public health problem on account of the raised prevalence of the disease. The incidence of fatal asthma is estimated at 3/100,000 people in France and the incidence of fatal asthma has not ceased to rise in the world despite therapeutic progress. The principal risk factors recognised are: 1. longstanding asthma, 2. unstable asthma, 3. acute severe asthma with a prior history, 4. insufficiently treated asthma or poorly compliant patient, 5. the absence of surveillance by peak flow measurements, etc. The socio-economic factors and above all the psychological factors play a role which is not negligible. A poor evaluation of the severity of the crisis by the asthmatic has been suggested as a factor, but it is possible that the rapidity of the progression of the crisis in fatal asthma may be responsible for the physical inability of the patient to react to the situation. There is no reason to incriminate beta-mimetic agents in fatal asthma. The prevention rests on an improvement in treatment, the education of the asthmatic and an improvement in medical teaching. However, only improvement in the speed of admission of emergency cases will effectively permit a reduction in the incidence of fatal asthma. The system of auto-admission of patients at risk should be reserved for co-operative patients but the systematic medicalization for urgent cases of asthma merits further development. A better definition of the asthmatic population at risk for fatal asthma is necessary.

Adolescent

Hemorrhagic shock with paradoxical bradycardia.

Two hundred and seventy-three acute hemorrhagic shocks were treated in 1984 in a pre-hospital emergency care unit. Twenty patients (7%) had a paradoxical bradycardia: they were conscious, 9 of them had an undetectable systolic arterial pressure with the sphygmomanometric method but the femoral pulse was still present. All of them recovered from bradycardia with fluid loading alone. The comparison between patients with paradoxical bradycardia and those with tachycardia showed that the former had more severe and rapid hemorrhages. During 1985, 7 new cases of acute hemorrhagic shock with paradoxical bradycardia were treated with an antishock trouser. These patients recovered from bradycardia more quickly (p less than 0.01) and with a less important fluid loading (p less than 0.01) than those previously treated without the antishock trouser. Two other patients were treated with atropine before antishock trouser inflation and experienced ventricular premature beats and one developed ventricular fibrillation. A paradoxical bradycardia can occur in hemorrhagic shock and denotes a rapid and severe hemorrhage requiring a massive and rapid fluid loading. The preliminary results of the antishock trouser in this setting are encouraging. The treatment of bradycardia per se may be deleterious and atropine must be avoided in conscious patients with hemorrhagic shock and paradoxical bradycardia.

Adolescent

Prevention of fatal asthma.

Over a 32-month period, 980 calls from asthmatic patients were received at the switchboard office of a prehospital emergency care unit. A total of 90 patients (9 percent) died before receiving any medical help, and 216 (22 percent) patients were taken to the hospital with an emergency care ambulance where none of them died. We made the assumption that, when an asthmatic patient calls an emergency care unit, the attack is severe and might be fatal. A prospective study was performed during a six-month period to prevent these asthma deaths: 259 calls from asthmatic patients were received. For each emergency call from asthmatic patients, paramedical help (delay: 5.1 +/- 0.3 minutes) and an emergency care ambulance (delay: 9.7 +/- 0.6 minutes) were immediately sent. Only four patients died during this period. Emergency calls from asthmatic patients must be considered as related to a severe attack that might be fatal. Fatal asthma is often related to a severe attack that evolves rapidly. Some asthmatic patients are able to assess the severity of asthma attacks, and prehospital emergency care schemes for asthmatic patients are actually able to prevent some asthma deaths.

Asthma