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Biomedical subjects

G Orliaguet

Publications and source records attributed to G Orliaguet.

At least 37 records · Page 2Linked to original sources

[Acute hemolysis following perioperative blood salvage in chldren operated for the surgical correction of craniosynostosis].

We report the case of a 6-month-old child, who suffered from acute haemolysis following transfusion of salvaged blood. This complication, of favourable outcome, was related to the accidental aspiration of benzalkonium chloride into the cell saver. This case emphasizes that any adjunction of antiseptic solution is contraindicated during blood saving. The use of a cell saver must be associated with written protocols, describing clearly the contraindications, precautions of use, and the different steps of use of this method of autologous blood transfusion.

Acute Disease↗

[Pulmonary embolism in sclerotherapy for a venous malformation in a child under general anesthesia].

We report a case of pulmonary embolism associated with percutaneous sclerotherapy (absolute ethanol: 0.5 mL.kg-1) of a venous angioma, performed under general anaesthesia in a 13 year-old child. The diagnosis of pulmonary embolism, suspected on the clinical setting and symptoms, was supported by the pulmonary scintigraphy obtained 4 hours later, showing 3 minimal pulmonary defects. The outcome was rapidly favourable without sequelae under heparin administration and the pulmonary scintigraphy, performed on day 7, was normal. The role of absolute ethanol, for explaining the apparent contrast between the severity of the symptoms and the minimal obstruction noted on pulmonary scintigraphy is discussed. Also discussed are the prophylactic and curative therapeutic issues of this severe complication.

Anesthesia, General↗

[A case of hepatic pseudoaneurysm treated with percutaneous embolization in a child with multiple trauma].

Hepatic artery pseudoaneurysms are rare complications of blunt abdominal trauma in children. Diagnosis is frequently delayed and made by splanchnic angiography. Most of the indications for surgical treatment have disappeared after the development of selective catheterization and embolization. We report a case in an 8-year-old pedestrian who was struck by a car and suffered a multiple trauma with a severe blunt abdominal trauma. A severe collapse upon admission commanded immediate laparotomy that depicted a liver fracture with associated jejunal and pancreatic lesions. Recovery was progressive until the 15th postoperative day where an abrupt haemobilia occurred. A CT-scan exploration was performed and revealed a vascular mass lesion in the left lobe of the liver. The performance of a selective angiography confirmed the diagnosis of left artery pseudoaneurysm, but because of technical difficulties, no embolization could be performed by this way. A direct percutaneous puncture and embolization of the aneurysm allowed a complete exclusion of the lesion. Eventually, recovery was complete. This percutaneous technique could be a valuable alternative to classical embolization and could avoid surgical treatment that still carries a high morbidity.

Aneurysm, False↗

Effects of dantrolene on rat diaphragm muscle during postnatal maturation.

BACKGROUND: Dantrolene is the only known effective treatment for malignant hyperthermia. However, its effects on diaphragm muscle during postnatal maturation remain unknown. METHODS: The effects of dantrolene (10(-8) to 10(-4) M) were investigated in vitro on diaphragm muscle strips in adult rats and in postnatal rats aged 3, 10, and 17 days, and compared with those of ryanodine (10(-8) to 10(-6) M). The authors studied contraction and relaxation under isotonic and isometric conditions (29 degrees C, Krebs-Henseleit solution, tetanic stimulation at 50 Hz). Data are mean +/- SD. RESULTS: During postnatal maturation, the authors observed a progressive increase in active force developed per cross-sectional area (from 34 +/- 25 to 69 +/- 32 mN/mm2; P < 0.05) and maximum shortening velocity (from 2.9 +/- 0.5 to 4.9 +/- 1.4 Lmax/s; P < 0.05). Dantrolene induced a negative inotropic effect in diaphragm muscles in isotonic and isometric conditions in all groups, but this effect was significantly less marked in the 3-day-old rats compared with older rats. Dantrolene did not induce significant lusitropic effects during postnatal maturation. Developmental changes in the pharmacologic response to dantrolene were more rapid than those of ryanodine. CONCLUSION: Dantrolene induced less pronounced negative inotropic effects on the diaphragm in neonatal rats as compared with adult rats. Our study suggests that developmental changes in the pharmacologic response to dantrolene are more rapid than those of ryanodine.

Aging↗

Minimum alveolar concentration of volatile anesthetics in rats during postnatal maturation.

BACKGROUND: Although neonatal rats have become widely used as experimental laboratory animals, minimum alveolar concentration (MAC) values of volatile anesthetics in rats during postnatal maturation remain unknown. METHODS: We determined MAC values of volatile anesthetics in spontaneously breathing neonatal (2-, 9-, and 30-day-old) and adult Wistar rats exposed to increasing (in 0.1-0.2% steps) concentrations of halothane, isoflurane, or sevoflurane (n = 12-20 in each group), using the tail-clamp technique. MAC and its 95% confidence intervals were calculated using logistic regression and corrected for body temperature (37 degrees C). RESULTS: In adult rats, inspired MAC values corrected at 37 degrees C were as follows: halothane, 0.88% (confidence interval, 0.82-0.93%); isoflurane, 1.12% (1.07-1.18%); and sevoflurane, 1.97% (1.84-2.10%). In 30-day-old rats, the values were as follows: halothane, 1.14% (1.07-1.20%); isoflurane, 1.67% (1.58-1.76%); and sevoflurane, 2.95% (2.75-3.15%). In 9-day-old rats, inspired MAC values were as follows: halothane, 1.68% (1.58-1.78%); isoflurane, 2.34% (2.21-2.47%); and sevoflurane, 3.74% (3.64-3.86%). In 2-day-old rats, inspired MAC values were as follows: halothane, 1.54% (1.44-1.64%); isoflurane, 1.86% (1.72-2.01%); and sevoflurane, 3.28% (3.09-3.47%). CONCLUSION: As postnatal age increases, MAC value significantly increases, reaching the greatest value in 9-day-old rats, and decreases thereafter, and at 30 days is still greater than the adult MAC value.

Age Factors↗

[Effect of a lung contusion on the prognosis of severe head injury in the child].

OBJECTIVES: To assess the effects of a pulmonary contusion (PC) on the outcome of a severe head trauma (SHT) in children less than 15-year-old. STUDY DESIGN: Retrospective study. PATIENTS: The study included 30 severely head injured children with a Glasgow Coma Scale score (GCS) < or = 8, associated with a PC (PC+) diagnosed on a thoracic CT-scan and 30 severely head injured children without PC (PC-). METHODS: Outcome was assessed using the Glasgow Outcome Scale (GOS), on discharge and six months later. Age, body weight, gender, GCS, PTS, ISS, hypoxaemia, arterial hypotension, the results of the cerebral CT-scan, the main treatment administered, complications, the duration of tracheal intubation as well as the duration of stay in the intensive care unit (ICU) and in the hospital were compared between groups. RESULTS: GCS median was lower (6 vs 8, P = 0.001) and ISS median higher (25 vs 23, P = 0.0004) in the PC+ group. Hypoxaemia was more frequent in the PC+ group (n = 12 vs n = 0, P = 0.0001). There was no difference between groups regarding the results of cerebral CT scan. Blood transfusion was more frequently used in the PC+ group (n = 14 vs n = 5, P = 0.03). Median duration of tracheal intubation, and of stay in the ICU and in the hospital were shorter in the PC- group (respectively 8 vs 6 days, P = 0.03; 10 vs 7.5 days, P = 0.008; 13.5 vs 10.5 days, P = 0.01). No difference was observed regarding complications between groups. GOS on discharge was higher in the PC+ group (3 vs 2, P = 0.01). There was an increase in GOS at six months in the two groups, however GOS remained significantly higher in the PC+ group (median values 2 vs 1, P = 0.002). A favourable outcome occurred less frequently in the PC+ group on discharge and at six months (respectively n = 14 vs 25, P = 0.006; n = 20 vs 28, P = 0.02). CONCLUSION: The association of a PC to a severe head trauma is responsible for a poorer outcome in children, probably because, at least in part, a higher incidence of hypoxaemia.

Adolescent↗

Complications of emergency tracheal intubation in severely head-injured children.

A high incidence of unsuccessful attempts and complications has been reported when emergency tracheal intubation (ETI) is performed outside the hospital in severely injured children. The aim of this prospective series was to analyse the incidence and related risk factors of complications of emergency tracheal intubation. The time to complete successful ETI and occurrence of incidents, e.g. cough reflex, hypoxia or spasm were related to the experience of the physician performing intubation and the use of drugs to facilitate ETI. The incidence of hypoxia, hypercarbia, postintubation complications such as extubation stridor and long-term sequelae were noted. Of the 188 children, 78% were successfully intubated at the site of the accident, 10% upon arrival at a local hospital from where they were secondarily transferred and 12% upon admission to our trauma centre. The most severely injured children were intubated in the field in 98% of cases without failure, nor life-threatening complications related to ETI. The experience of the operator influenced the number of attempts and the time to complete successful intubation. Immediate incidents were noted in 25% of children, e.g. cough in 18%. The regimen of drugs, but not level of consciousness, influenced the incidence of immediate incidents; without drugs, more than 67% experienced incidents. Early tracheal intubation and controlled ventilation resulted in adequate ventilation upon arrival (mean PaO2 of 35.8+/-24 kPa, mean PaCO2 of 4.35+/-1 kPa). Long-term complications, including transient stridor upon extubation in 33% of the cases, and laryngeal granuloma or tracheal stenosis, were comparable to those in other series. ETI in shocked patients and pulmonary infection in hospital, but not the technique of ETI, increased the risks of long-term complications. Emergency tracheal intubation can be performed safely in the field, and results in adequate ventilation during transportation of severely injured children, provided that it can be performed by trained physicians using adequate drugs to facilitate intubation.

Child↗

Critical care management of neurotrauma in children: new trends and perspectives.

Secondary brain lesions resulting from cerebral metabolic and hemodynamic reactions can be prevented by neurocritical care management. It must be initiated as soon as possible, ideally in a prehospital setting. Tracheal intubation, controlled ventilation and hemodynamic stabilization are the prerequisites. Beside intracranial and cerebral perfusion pressure, monitoring must evaluate the coupling between cerebral metabolic demand and blood flow. Jugular bulb oximetry is the most reliable approach to global cerebral coupling. Transcranial Doppler evaluates cerebral blood flow indirectly and noninvasively. Technological developments have led to local metabolic evaluation that does not yet have any clinical relevance. Therapeutic developments are more a new approach to the use of old drugs. Controlled hyperventilation, mannitol and, more recently, hypertonic saline solutions, used for restoring cerebral metabolic coupling, are the foundations of treatment. Thiopental, revisited as a vasoconstrictive agent, the "Lund" vasoconstrictive approach with anti-hypertensive drugs and cerebral vasoconstrictors, must be further evaluated in children, as must therapeutic hypothermia. Finally, what we probably need for the immediate future is a noninvasive and easily reproducible method of monitoring cerebral metabolic coupling that will allow precise therapeutic adaptation of multimodal therapy to the individual needs of the child.

Brain Injuries↗

[Pharmacodynamics and safety of mivacurium in infants and children under halothane-nitrous oxide anesthesia].

OBJECTIVES: To determine pharmacodynamic effects and safety of mivacurium in paediatric patients. STUDY DESIGN: Multicentric, prospective, open, non-randomized study. PATIENTS: Forty-eight three-month-old to eight-year-old physical class ASA I or II children. METHOD: Anaesthesia was induced and maintained with halothane and nitrous oxide. Tracheal intubation was performed without a neuromuscular blocking agent. Neuromuscular blockade was measured with a strain force transducer after train-of-four stimulation of the ulnar nerve at the wrist every ten seconds. A single bolus dose of mivacurium (0.2 mg.kg-1) was injected during 15 seconds in patients allocated into three groups. Group 1: three to 12-month-old infants (n = 15), group 2: one- to three-year-old children (n = 16) and group 3: three- to eight-year-old children (n = 17). Onset and recovery parameters were measured in each patient. Heart rate and noninvasive arterial blood pressure were recorded every minute for five minutes after mivacurium injection. RESULTS: Following halothane administration for 29 and 32 min, and a FEThalothane = 1 vol%, mivacurium (0.2 mg.kg-1) determined a 100% neuromusmcular blockade in all patients. The onset time was 71 +/- 34 s (mean +/- SD) in all patients and did not differ between groups. Time to 25% and 95% recovery of the first twitch and recovery index for all the patients were 12 +/- 3 min, 19 +/- 5 min and 4 +/- 2 min respectively and did not differ between groups. No prolonged paralysis was observed. No significant changes of HR and BP occurred. CONCLUSIONS: Following 0.2 mg.kg-1 of mivacurium in patients aged between three months to eight years, a complete blockade occurs with a rapid onset time and a short duration of action, without significant cardiovascular effect.

Anesthetics, Inhalation↗

The effects of dantrolene on the contraction, relaxation, and energetics of the diaphragm muscle.

UNLABELLED: Dantrolene is used in patients with muscle spasticity and is the only known effective treatment for malignant hyperthermia. However, its effects on muscle relaxation and energetics are unknown and may have important consequences in diaphragmatic function. We studied the effects of dantrolene (10(-8) to 10(-4) M) on diaphragm muscle strips (n = 12) in the hamster in vitro (Krebs-Henseleit solution, 29 degrees C, 95% oxygen/5% carbon dioxide) in response to tetanic stimulation (50 Hz). We studied contraction and relaxation under isotonic and isometric conditions, as well as energetics. Data are mean +/- SD. Dantrolene induced a negative inotropic effect in the hamster diaphragm (active force at 10(-4) M: 34% +/- 7% of baseline; P < 0.05) but did not significantly modify the curvature of the force-velocity relationship. Dantrolene did not significantly modify isotonic relaxation. Dantrolene, up to 10(-5) M, did not significantly impair isometric relaxation. In conclusion, dantrolene induced a marked negative inotropic effect on diaphragm muscle without affecting myothermal efficiency and relaxation. IMPLICATIONS: Dantrolene induced a significant and concentration-dependent negative inotropic effect on diaphragm muscle but did not modify isotonic relaxation, which suggests no alteration of the calcium reuptake by the sarcoplasmic reticulum; up to 10(-5) M dantrolene did not alter isometric relaxation, i.e., myofilament calcium sensitivity. Dantrolene did not modify the energetics of diaphragm muscle.

Animals↗

Effects of dantrolene on the diaphragm muscle of the normal and myopathic hamster.

Dantrolene is the only known effective treatment for malignant hyperthermia. However, its effects on the myopathic diaphragm remain unknown. The effects of dantrolene 10(-8) to 10(-4) mol litre-1 on diaphragm muscle strips in normal (n = 12) and myopathic hamsters (n = 13) were investigated in vitro in response to tetanic stimulation. We studied contraction under isotonic and isometric conditions. Data are presented as mean (SD) percent of baseline. Dantrolene induced a negative inotropic effect in normal and myopathic hamsters but no significant difference was observed between groups (active force at 10(-4) mol litre-1; 34 (7) vs 32 (11)%; ns). We conclude that dantrolene induced a comparable negative inotropic effect on diaphragm muscle in normal and myopathic hamsters.

Animals↗

[Anesthesia and intensive care of craniostenosis and craniofacial dysmorphism in children].

Craniosynostosis occurs in one out of 2,000 births. It results in primary skull deformations requiring surgical repair, in infants with a body weight of less than 10 kg. Pure craniosynostosis is the most frequent situation, where the risk for cerebral compression during brain development is the lowest. Therefore the aim of surgical correction in this case is mainly cosmetic. Conversely, in syndromic craniosynostosis, associated malformations are more common and cerebral, visual and respiratory consequences of complex facio-craniosynostosis are usually severe. Current surgical techniques consist of a total skull vault reconstruction which carry a high risk of sudden and major blood losses. Intraoperatively, whatever the type of craniosynostosis, mean blood losses corresponding to 90% of estimated red cell mass have to be anticipated. These blood losses vary according to the type of skull deformation and the type of surgery. Accurate evaluation is usually difficult and must be based more on calculation of red cell mass variations than on simple monitoring of surgical drainage. Invasive haemodynamic monitoring is always required. To reduce the amount of homologous blood transfusion, peroperative haemodilution seems to be the most suitable technique, due to unresolved technical difficulties in autotransfusion practice in infants. Severe facial deformities are associated with chronic hypoxaemia and cerebral compression representing major risk for these children in poor condition undergoing such major surgical procedures. With experienced teams, this high-risk surgery carries a low peroperative mortality (less than 1%) and morbidity rate. The latter includes essentially transient peroperative hypotension. The excellent final cosmetic and functional results justify the practice of this surgery in children with a bodyweight of less than 10 kg.

Anesthesia, General↗

Comparison of the effects of ketamine-midazolam with those of fentanyl-midazolam on cortical somatosensory evoked potentials during major spine surgery.

Cortical somatosensory evoked potentials (CSEP) allow monitoring of spinal cord function during surgery. Ketamine has been shown to enhance CSEP amplitude, but there is no previous study comparing its effects with those of other anaesthetic regimens. Therefore, we have compared the effects of ketamine with those of fentanyl, both combined with midazolam, on CSEP monitoring during major spine surgery. Twenty patients with normal preoperative CSEP were allocated randomly to a ketamine or fentanyl group. Anaesthesia was induced with ketamine 3 mg kg-1 or fentanyl 6 micrograms kg-1 i.v., and midazolam 0.3 mg kg-1 i.v in both groups, and maintained with continuous i.v infusion of ketamine 2 mg kg-1 h-1 or fentanyl 3 micrograms kg-1 h-1, combined in both groups with midazolam 0.15 mg kg-1 h-1 and 60% nitrous oxide in oxygen. CSEP were elicited by tibial posterior nerve stimulation and measured P1 and N1 latencies, and P1-N1 amplitude, CSEP were recorded before and after induction, at 15 min, 1 and 2 h after induction, during skin closure and after removal of nitrous oxide. Both groups were comparable in characteristics, duration of surgery, mean arterial pressure and temperature. CSEP latencies were not significantly affected in either group. CSEP amplitude decreased significantly over time in the fentanyl group (from mean 2.02 (SEM 0.41) to 0.95 (0.17) microV, P < 0.05), but not in the ketamine group (from 1.33 (0.36) to 1.05 (0.31) microV, ns). Nevertheless, we did not observe any significant differences in amplitudes or latencies between the two groups. The delay in obtaining the first voluntary postoperative motor response was significantly greater in the ketamine group (170 (54) vs 55 (17) min, P < 0.01). Both ketamine and fentanyl allowed us to obtain reliable CSEP during major spine surgery, and there were no significant difference between these two anaesthetic regimens for CSEP monitoring, but a longer delay for voluntary postoperative motor assessment was observed in the ketamine group.

Adult↗