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Biomedical subjects

Olivier Langeron

Publications and source records attributed to Olivier Langeron.

18 recordsLinked to original sources
PubMed2006

Diagnosis of bowel and mesenteric injuries in blunt abdominal trauma: a prospective study.

PURPOSE: Currently, nonoperative management is the procedure of choice for solid organ injury in patients with a blunt abdominal trauma. Missed blunt bowel and mesenteric injuries (BBMIs) are possible because diagnosis is difficult. The aim of our study was to test a new algorithm for BBMI diagnosis using abdominal ultrasonography (AUS), computed tomography (CT), and diagnostic peritoneal lavage (DPL). METHODS: We reviewed cases of blunt abdominal injuries over a 10-year period, then we designed an algorithm that was prospectively tested in hemodynamically stable patients over a 2-year period. An abnormal AUS led to helical CT. When the CT showed more than 2 findings suggestive of BBMI, laparotomy was performed. In case of 1 or 2 abnormal CT findings, we performed a DPL and calculated the ratio of white blood cells (WBCs) to red blood cells (RBCs) (WBC/RBC ratio) in the lavage fluid and divided this by the WBC/RBC ratio in peripheral blood. A ratio of 1 or higher was considered positive for BBMI, and a laparotomy was immediately performed. Patients with a ratio of less than 1 were managed nonoperatively. RESULTS: In the retrospective study, 26 (1%) of 2126 patients admitted to our trauma center for blunt trauma had a BBMI, including 15 (58%) diagnosed after a median delay of 24 hours. In the prospective study, 531 patients were admitted for blunt trauma with multiple injuries, including 131 with abdominal trauma. Computed tomography was performed in 40 patients. There were 2 criteria or more of BBMI in 1 patient, 0 criteria in 27 patients (with an uneventful follow-up), and 1 or 2 criteria in 12 patients who had DPL with a median ratio of 0.82 (ranges, 0.03-9). Five patients had a ratio of 1 or higher. They underwent immediate laparotomy. In all 5 cases, BBMI was found. The 7 patients who had a ratio of less than 1 were observed in ICU and treated for extra-abdominal injuries. No BBMI injury was missed in these patients. The accuracy of the algorithm was 100% (95% confidence interval, 0.99-1.00). CONCLUSION: The proposed algorithm (based on AUS, CT, and DPL) had a high accuracy to diagnose BBMI while requiring the performance of DPL in only a few (2%) patients.

Abdominal Injuries↗
PubMed2006

Comparison of plastic single-use and metal reusable laryngoscope blades for orotracheal intubation during rapid sequence induction of anesthesia.

BACKGROUND: Plastic single-use laryngoscope blades are inexpensive and carry a lower risk of infection compared with metal reusable blades, but their efficiency during rapid sequence induction remains a matter of debate. The authors therefore compared plastic and metal blades during rapid sequence induction in a prospective randomized trial. METHODS: Two hundred eighty-four adult patients undergoing general anesthesia requiring rapid sequence induction were randomly assigned on a weekly basis to either plastic single-use or reusable metal blades (cluster randomization). After induction, a 60-s period was allowed to complete intubation. In the case of failed intubation, a second attempt was performed using metal blade. The primary endpoint of the study was the rate of failed intubations, and the secondary endpoint was the incidence of complications (oxygen desaturation, lung aspiration, and oropharynx trauma). RESULTS: Both groups were similar in their main characteristics, including risk factors for difficult intubation. On the first attempt, the rate of failed intubation was significantly increased in plastic blade group (17 vs. 3%; P < 0.01). In metal blade group, 50% of failed intubations were still difficult after the second attempt. In plastic blade group, all initial failed intubations were successfully intubated using metal blade, with an improvement in Cormack and Lehane grade. There was a significant increase in the complication rate in plastic group (15 vs. 6%; P < 0.05). CONCLUSIONS: In rapid sequence induction of anesthesia, the plastic laryngoscope blade is less efficient than a metal blade and thus should not be recommended for use in this clinical setting.

Adult↗
PubMed2006

Lightwand tracheal intubation with and without muscle relaxation.

BACKGROUND: Lightwand tracheal intubation is a suitable technique for patients who are difficult to intubate but who are receiving effective ventilation. The effect of muscle relaxants on the efficacy of lightwand intubation has not yet been evaluated. The authors conducted a prospective, double-blind, placebo-controlled study to assess the effectiveness and incidence of complications of lightwand tracheal intubation performed during general anesthesia with and without the use of a muscle relaxant in patients with apparently normal airway anatomy. METHODS: One hundred seventy-six patients who required orotracheal intubation were prospectively included. Anesthesia was administered using propofol (2 mg/kg, then 3 mg . kg (-1). h(-1)) and remifentanil (1 microg/kg, then 0.3 microg . kg(-1) . min(-1)). Patients were randomly assigned to one of two groups (n = 88 for each) to receive rocuronium 0.6 mg/kg or saline intravenously. Lightwand orotracheal intubation (Trachlight; Laerdal Medical Inc., Armonk, NY) was attempted after 3 min. The authors recorded the number of successful intubations, the number of attempts and their duration, and events during the procedure. RESULTS: The failure rate of lightwand intubation was 12% in the placebo group and 2% in the rocuronium group (P = 0.021). Patients in the placebo group received more multiple intubation attempts (P < 0.001), required a greater intubation time (77 +/- 65 vs. 52 +/- 31 s; P = 0.002) and experienced a greater incidence of events during intubation (61 vs. 0%; P < 0.001) than patients in the rocuronium group. CONCLUSIONS: The use of muscle relaxants in patients with apparently normal airways is associated with a lower failure rate, decreased intubation time, and fewer attempts when performing lightwand orotracheal intubation.

Adult↗
PubMed2006

An evaluation of transcutaneous carbon dioxide partial pressure monitoring during apnea testing in brain-dead patients.

BACKGROUND: Diagnosis of brain death usually requires an arterial carbon dioxide partial pressure (Paco2) of 60 mmHg during the apnea test, but the increase in Paco2 is unpredictable. The authors evaluated whether transcutaneous carbon dioxide partial pressure (Ptcco2) monitoring during apnea test can predict that a Paco2 of 60 mmHg has been reached. METHODS: The authors compared Ptcco2 measured with a transcutaneous ear sensor (V-Sign Sensor, Sentec Digital Monitoring System; SENTEC-AG, Therwil, Switzerland) and Paco2 obtained from arterial blood gas measurements in 32 clinically brain-dead patients. RESULTS: In the first 20 patients, the mean Paco2-Ptcco2 gradient was 0.7 +/- 3.6 mmHg at baseline and 8.7 +/- 7.1 mmHg after 20 min of apnea. Using receiver operating characteristic curve analysis (area under the curve: 0.983 +/- 0.013), the best threshold value of Ptcco2 to predict that a Paco2 of 60 mmHg had been reached was 60 mmHg (positive predictive value: 1.00 [0.93-1.00]). In the following 12 patients investigated with use of this Ptcco2 target value of 60 mmHg, the mean duration of the apnea test (11 +/- 4 vs. 20 +/- 0 min; P < 0.001), hypercapnia (74.0 +/- 4.9 vs. 98.3 +/- 20.0 mmHg; P < 0.001), acidosis (pH: 7.18 +/- 0.06 vs. 7.11 +/- 0.08; P < 0.001), and decrease in arterial oxygen partial pressure (-47 +/- 44 vs. -95 +/- 89; P < 0.05) at the end of the test were reduced as compared with the 20-min apnea test group. CONCLUSION: During the apnea test in brain-dead patients, a Ptcco2 of 60 mmHg accurately predicts that a Paco2 of 60 mmHg has been reached. This may allow a reduction in the duration of the apnea test and consecutively limit occurrence of complications.

Adult↗
PubMed2006

Clinical review: management of difficult airways.

Difficulties or failure in airway management are still important factors in morbidity and mortality related to anesthesia and intensive care. A patent and secure airway is essential to manage anesthetized or critically ill patients. Oxygenation maintenance during tracheal intubation is the cornerstone of difficult airway management and is always emphasized in guidelines. The occurrence of respiratory adverse events has decreased in claims for injuries due to inadequate airway management mainly at induction of anesthesia. Nevertheless, claim reports emphasize that airway emergencies, tracheal extubation and/or recovery of anesthesia phases are still associated with death or brain damage, indicating that additional educational support and management strategies to improve patient safety are required. The present brief review analyses specific problems of airway management related to difficult tracheal intubation and to difficult mask ventilation prediction. The review will focus on basic airway management including preoxygenation, and on some oxygenation and tracheal intubation techniques that may be performed to solve a difficult airway.

Algorithms↗
PubMed2005

Early hypocalcemia in severe trauma.

OBJECTIVES: We tested the hypothesis that colloid-induced hemodilution can induce hypocalcemia in the early phase of severe trauma resuscitation and tried to assess other potential causative factors of that hypocalcemia. DESIGN: Prospective cohort. SETTING: Level I academic trauma center. PATIENTS: Consecutive severe trauma patients (n = 212, mean Injury Severity Score 34) resuscitated in the prehospital phase without any blood transfusion. INTERVENTIONS: At admission, ionized calcium (corrected to an arterial pH = 7.40) was measured. MEASUREMENTS AND MAIN RESULTS: Hypocalcemia was defined as a value <1.15 mmol/L and severe hypocalcemia as a value <0.9 mmol/L. A normal ionized calcium concentration was observed in 56 (26%) patients, a mild ionized hypocalcemia (1.05 +/- 0.06 mmol/L) in 135 (64%) patients, and a severe ionized hypocalcemia (0.77 +/- 0.10 mmol/L) in 21 (10%) patients. There were significant correlations between ionized calcium concentration with the amount of infused colloid (R = .658, p < .001) and arterial pH (R = .760, p < 0.001) but not with the amount of infused crystalloid (R = .007, not significant). Despite taking into account hemodilution, arterial pH, binding of calcium to lactates, and colloids, some patients had marked differences (>15%) between calculated and observed ionized calcium, and these patients had more severe trauma and more frequently had acidosis and/or prehospital cardiac arrest. Using the TRISS methodology, survival was not significantly different from that expected in this trauma population. CONCLUSION: Hypocalcemia frequently occurs on arrival at the hospital in severe trauma patients, and colloid-induced hemodilution and severe shock and/or ischemia-reperfusion appear to be important causative factors.

Acidosis↗
PubMed2005

[Spinal cord trauma: epidemiology and pre-hospital management].

In France, about 2000 people suffer spinal cord injuries each year. Most patients are young men involved in road accidents and most have cervical lesions. Emergency pre-hospital care is crucial, as the lesions are potentially life-threatening and can have devastating functional consequences. The possibility of spinal cord trauma must always be kept in mind, and the spine must be immobilized. The initial neurological examination is extremely important. Initial medical care should target an average systolic blood pressure above 80 mmHg, ensure adequate ventilation, maintain the body temperature over 36 degrees C, and control hyperglycemia. The patient should be transported rapidly to a specialized spinal trauma unit.

Emergency Medical Services↗
PubMed2004

A high initial VAS score and sedation after iv morphine titration are associated with the need for rescue analgesia.

PURPOSE: Administration of sc morphine has been recommended two hours after the end of iv morphine titration in the postanesthesia care unit (PACU), but in some cases patients complain of pain earlier than this. We assessed pain after the end of iv morphine titration and studied the characteristics of patients who needed rescue sc morphine. METHODS: Postoperative pain was assessed using the visual analogue scale (VAS; 0 to 100) and the threshold required to administer morphine in the PACU was a score of 30. VAS was measured every 15 min up to two hours after the end of iv morphine titration. Patients were divided into two groups, those who required sc morphine before two hours and those who did not. Data are expressed as mean +/- SD or odds ratio (OR; 95% confidence interval). RESULTS: Four hundred and two patients were analyzed. Mean age was 51 +/- 19 yr, initial VAS 69 +/- 19, and the dose of iv morphine 11.7 +/- 6.6 mg. The number of patients requiring sc morphine within two hours was 84 (21%). These patients had more severe initial postoperative pain (73 +/- 20 vs 68 +/- 19, P < 0.05), and experienced sedation more frequently during morphine titration (45 vs 25%, P < 0.001). Using a multivariate analysis, occurrence of sedation during titration [OR 2.3 (1.4-3.8), P < 0.001] and an initial pain score > or = 60 [OR 1.9 (1.0-3.4), P < 0.05] were significantly associated with the need for rescue sc morphine. CONCLUSION: Sedation during titration and an initial VAS > or = 60 are characteristics of the patients who require rescue (less than two hours) sc morphine after iv morphine titration.

Aged↗
PubMed2004

Mechanical properties of tracheal smooth muscle are impaired in the rabbit with experimental cardiac pressure overload.

UNLABELLED: STUDY OBJECTIVES/DESIGN: Impaired function of striated and arterial smooth muscle is known to occur in humans and animals with various forms of cardiac diseases, but limited information is available on the mechanical behavior of airway smooth muscle. We tested the hypothesis that the baseline mechanical properties of tracheal smooth muscle (TSM) were impaired at an early stage of cardiac overload. ANIMALS: We used a model of cardiac hypertrophy induced by surgical abdominal aortic stenosis (AS) in adult rabbits. Twelve animals with AS and 8 sham-operated control rabbits were studied 12 weeks after surgery. In rabbits with AS, the heart weight/body weight ratio was higher than in control rabbits (2.36 +/- 0.43 g/kg vs 1.98 +/- 0.20 g/kg, p < 0.05) [mean +/- SD], attesting to moderate cardiac hypertrophy. No clinical signs of congestive heart failure were observed. MEASUREMENTS: Isolated TSM strips were electrically stimulated at 37 degrees C, 2.5 mM [Ca(2+)](0), against 8 to 10 load levels, from zero load to full isometry. Force-velocity relationship was elicited using the conventional afterloaded isotonic method. RESULTS: Peak isometric tension was lower in rabbits with AS than in control rabbits (25 +/- 11 mN/mm(2) vs 34 +/- 14 mN/mm(2), p < 0.05), whereas maximum unloaded shortening velocity, maximum extent of muscle shortening, and relaxation parameters did not differ between groups. The curvature of the force-velocity relationship (which reflects the myothermal economy of force generation) and peak mechanical efficiency were lower in rabbits with AS than in control rabbits. CONCLUSIONS: These results indicate that the contraction of isolated rabbit TSM was less powerful and less economical in cardiac hypertrophy, attesting to early impairment of the mechanical properties of TSM during cardiac overload.

Animals↗
PubMed2003

Relationships between measurement of pain using visual analog score and morphine requirements during postoperative intravenous morphine titration.

BACKGROUND: Although intravenous morphine titration is widely used to obtain rapid and complete postoperative pain relief, the relationship between measurement of pain and morphine requirements varies, and the evolution of pain during titration is poorly understood. METHODS: Intravenous morphine titration was administered as a bolus of 2 (body weight < or = 60 kg) or 3 mg (body weight > 60 kg) during the immediate postoperative period in the PACU. The interval between each bolus was 5 min. The visual analog scale (VAS) score threshold required to administer morphine was 30, and pain relief was defined as a VAS score of 30 or less. RESULTS: Data from 3,045 patients were analyzed. The mean initial VAS score was 73 +/- 19 (mean +/- SD), and the mean morphine dose required to obtain pain relief was 0.17 +/- 0.10 mg/kg, i.e., a median of four boluses (range, 1-20). When patients were grouped according to several classes of initial VAS score (31-39, 40-49, 50-59, 60-69, 70-79, 80-89, 90-100), it seemed that the relationship between VAS score and morphine requirements was a sigmoid curve. A VAS score of 70 or greater predicted the need for a high (>0.15 mg/kg) morphine dose (sensitivity, 0.77; specificity, 0.54). During the pain relief process, the relationship between VAS score and time was depicted by a sigmoid curve. CONCLUSION: A VAS score of 70 or greater should be considered indicative of severe pain. The relationship between the initial VAS score and morphine requirements is not linear, and the evolution of the VAS score during the pain relief process is described by a sigmoid curve.

Aged↗
PubMed2003

Overestimation of Bispectral Index in sedated intensive care unit patients revealed by administration of muscle relaxant.

BACKGROUND: Electromyographic activity has previously been reported to elevate the Bispectral Index (BIS) in patients not receiving neuromuscular blockade while under sedation in the intensive care unit. This study aimed to investigate the magnitude of the decrease of BIS following administration of muscle relaxant in sedated intensive care unit patients. METHODS: The authors prospectively investigated 45 patients who were continuously sedated with midazolam and sufentanil to achieve a Sedation-Agitation Scale value equal to 1 and who required administration of muscle relaxant. BIS (BIS version 2.10), electromyography, and acceleromyography at the adductor pollicis muscle were recorded simultaneously before and after neuromuscular blockade. Sixteen of these 45 patients were also studied simultaneously with the new BIS XP. RESULTS: After administration of a muscle relaxant, BIS (67 +/- 19 vs. 43 +/- 10, P < 0.001) and electromyographic activity (37 +/- 9 vs. 27 +/- 3 dB, P < 0.001) significantly decreased. Multiple regression analysis showed that the decrease of BIS following administration of myorelaxant was significantly correlated to BIS and electromyographic baseline values. Using standard BIS range guidelines, the number of patients under light or deep sedation versus general anesthesia or deep hypnotic state was markedly overestimated before administration of myorelaxant (53 vs. 2%, P < 0.001). CONCLUSIONS: The BIS in sedated intensive care unit patients may be lower with paralysis for an equivalent degree of sedation because of high muscular activity. The magnitude of BIS overestimation is significantly correlated to both BIS and electromyographic activity before neuromuscular blockade. The authors conclude that clinicians who determine the amount of sedation in intensive care unit patients only from BIS monitoring may expose them to unnecessary oversedation.

Anesthetics, Intravenous↗
PubMed2003

Postoperative morphine consumption in the elderly patient.

BACKGROUND: It has been suggested that the dose of intravenous morphine used during postoperative titration is not modified by aging. The authors therefore studied morphine requirements in patients undergoing total hip replacement. METHODS: Intravenous morphine titration was administered as boluses, then subcutaneous morphine was administered every 4 h over 24 h. Pain was assessed by use of the visual analog scale (0 to 100), and the threshold required to administer morphine was 30. Young and elderly (> or =70 yr old) patients were compared. Data are mean +/- SD or odds ratio (OR) [95% CI]. RESULTS: Two hundred twenty-four patients (68%) were young and 105 (32%) were elderly. The initial visual analog scale was not significantly different between groups. The dose of intravenous morphine in the postanesthesia care unit was not significantly different between young and elderly patients (0.15 +/- 0.11 vs. 0.14 +/- 0.10 mg/kg, P = NS), in contrast to the dose of subcutaneous morphine (0.18 +/- 0.18 vs. 0.11 +/- 0.11 mg/kg, P < 0.001) in the ward. Only severe pain (visual analog scale of 70 or greater; OR, 10.5 [4.5-24.8]) was significantly associated with a high dose (greater than 0.15 mg/kg) of intravenous morphine, whereas severe pain (OR, 2.5 [1.6-4.0]), age less than 60 yr (OR, 2.3 [1.4-3.8]), and absence of a nonsteroidal antiinflammatory drug (OR, 1.9 [1.2-3.1]) were significantly associated with a high dose (greater than 0.12 mg/kg) of subcutaneous morphine. CONCLUSIONS: The dose of intravenous morphine during titration is not modified in elderly patients, in contrast to the dose administered subcutaneously over a prolonged period.

Aged↗
PubMed2002

Detection of brain death onset using the bispectral index in severely comatose patients.

OBJECTIVES: To evaluate the accuracy of bispectral index (BIS) monitoring for the diagnosis of brain death in severely comatose patients. DESIGN: A prospective study in an intensive care unit of a university hospital. POPULATION: Fifty-six severely comatose patients (Glasgow Coma Score < or = 5) admitted to the ICU mainly because of intracerebral hemorrhage, head injury, or postanoxic coma. METHODS: BIS was recorded continuously during the hospitalization in the ICU. Where necessary, clinical brain death was confirmed by EEG or cerebral angiography. MEASUREMENTS AND RESULTS: Twelve patients were already clinically brain dead at the time of admission, and their individual BIS values were 0. In each of these 12 patients brain death was thereafter confirmed by EEG or cerebral angiography. Forty-four patients were not clinically brain-dead at the time of admission, and their individual BIS values were between 20 and 79. Twenty-seven of these patients became brain-dead, and their individual BIS values dropped to 0 in a few hours to a few days. In these 27 patients EEG or cerebral angiography was performed after the BIS value decreased to 0 and confirmed brain death in all cases. Seventeen patients who did not become brain dead during their hospitalization in the ICU had persistent electrocerebral activity on EEG, and their average BIS values remained above 35. CONCLUSION: BIS can be used in severely comatose patients as an assessment of brain death onset, enabling appropriate scheduling of either EEG or cerebral angiography to confirm brain death.

Brain Death↗
PubMed2002

Aprotinin versus placebo in major orthopedic surgery: a randomized, double-blinded, dose-ranging study.

UNLABELLED: We conducted a prospective, multicenter, double-blinded, dose-ranging study to compare the risk/benefit ratio of large- and small-dose aprotinin with placebo after major orthopedic surgery. Fifty-eight patients were randomized into three groups: Large-Dose Aprotinin (4 M kallikrein inactivator unit [KIU] bolus before surgery followed by a continuous infusion of 1 M KIU/h until the end of surgery), Small-Dose Aprotinin (2 M KIU bolus plus 0.5 M KIU/h), and Placebo. Bleeding was measured and calculated. Bilateral ascending venography was systematically performed on the third postoperative day. Measured and calculated blood loss decreased in the Large-Dose Aprotinin group (calculated bleeding, whole blood, hematocrit 30%, median [range], 2,023 mL [633-4,113] as compared with placebo, 3,577 mL [1,670-21,758 mL]). The total number of homologous and autologous units was also significantly decreased in the Large-Dose Aprotinin group (2 U [0-5 U] as compared with placebo, 4 U [0-42 U]). No increase in deep vein thrombosis or pulmonary embolism was observed in the aprotinin groups. Large-dose aprotinin was safe and effective in dramatically reducing the measured and calculated bleeding and the amount of transfused red blood cell units after major orthopedic surgery. IMPLICATIONS: Large doses of aprotinin decrease blood loss and transfusion amount in major orthopedic surgery.

Adult↗
PubMed2002

Postoperative titration of intravenous morphine in the elderly patient.

BACKGROUND: Intravenous morphine titration is used to obtain rapid and complete postoperative pain relief. Whether this titration can be safely administered in the elderly patients remains a matter for debate. METHODS: Intravenous morphine titration was administered as a bolus of 2 (body weight < or = 60 kg) or 3 (body weight > 60 kg) mg. The interval between each bolus was 5 min. There was no limitation in the number of boluses given until pain relief or severe adverse effect occurred. The visual analog scale threshold required to administer morphine was 30 mm, and pain relief was defined as a visual analog scale score of 30 mm or less. Patients were divided into two groups: young and elderly (age > or = 70 yr) patients. Data were expressed as mean +/- SD. RESULTS: Eight hundred seventy-five patients (83%) were young and 175 patients (17%) were elderly. At the end of morphine titration, the visual analog scale score and the number of patients with pain relief were not significantly different between groups. The total dose of morphine per kilograms of body weight administered was not significantly different between groups (0.15 +/- 0.10 vs. 0.14 +/- 0.09 mg/kg, not significant). No significant differences were observed in the incidence of morphine-related adverse effects (13 vs. 14%, not significant), the number of sedated patients (60 vs. 60%, not significant), and the number of patients whose titration had to be stopped (2 vs. 2%, not significant). CONCLUSION: Intravenous morphine titration can be safely administered to elderly patients. Because titration is adapted to individual pain, the same protocol can be applied to young and elderly patients.

Adult↗
PubMed2002

Effects of postnatal maturation on energetics and cross-bridge properties in rat diaphragm.

The effects of maturation on cross-bridge (CB) properties were studied in rat diaphragm strips obtained at postnatal days 3, 10, and 17 and in adults (10-12 wk old). Calculations of muscle energetics and characteristics of CBs were determined from standard Huxley equations. Maturation did not change the curvature of the force-velocity relationship or the peak of mechanical efficiency. There was a significant increase in the total number of CBs per cross-sectional area (m) with aging but not in single CB force. The turnover rate of myosin ATPase increased, the duration of the CB cycle decreased, and the velocity of CBs decreased significantly only after the first week postpartum. There was a linear relationship between maximum total force and m (r = 0.969, P < 0.001), and between maximum unloaded shortening velocity and m (r = 0.728, P < 0.001). When this study in the rat and previous study in the hamster are compared, it appears that there are few species differences in the postnatal maturation process of the diaphragm.

Actomyosin↗