Dyskalemia and cerebral insult: therapeutic barbiturate coma, endogenous catecholamine release or both?
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Adult↗
Biomedical subjects
P Lavagne
Publications and source records attributed to P Lavagne.
Identification of a non-linear model as a new method to detect expiratory airflow limitation in mechanically ventilated patients.
Expiratory flow limitation (EFL) can occur in mechanically ventilated patients with chronic obstructive pulmonary disease and other disorders. It leads to dynamic hyperinflation with ensuing deleterious consequences. Detecting EFL is thus clinically relevant. Easily applicable methods however lack this detection being routinely made in intensive care. Using a simple mathematical model, we propose a new method to detect EFL that does not require any intervention or modification of the ongoing therapeutic. The model consists in a monoalveolar representation of the respiratory system, including a collapsible airway that is submitted to periodic changes in pressure at the airway opening: EFL provokes a sharp expiratory increase in the resistance Rc of the collapsible airway. The model parameters were identified via the Levenberg-Marquardt method by fitting simulated data on the airway pressure and the flow signals recorded in 10 mechanically ventilated patients. A sensitivity study demonstrated that only 8/11 parameters needed to be identified, the remaining three being given reasonable physiological values. Flow-volume curves built at different levels of positive expiratory pressure, PEEP, during "PEEP trials" (stepwise increases in positive end-expiratory pressure to optimize ventilator settings) have shown evidence of EFL in three cases. This was concordant with parameter identification (high Rc during expiration for EFL patients). We conclude from these preliminary results that our model is a potential tool for the non-invasive detection of EFL in mechanically ventilated patients.
Adult↗
[Brain oedema following blood-brain barrier disruption: mechanisms and diagnosis].
Brain oedema following blood-brain barrier (BBB) disruption, or vasogenic oedema, is present in most cases of brain oedema. According to the Starling's law, water, ions and plasma proteins cross the BBB toward the interstitium if the driving forces for transmural bulk flow are excessive (mechanical origin) and/or if the BBB permeability is enhanced (chemical origin). Both mechanisms coexist in most cases. Excessive elevation of the gradient of hydrostatic pressure with lost of cerebral autoregulation has been proved in ischaemia/reperfusion and trauma, and suggested in acute mountain sickness and eclampsia. The BBB permeability can be enhanced by immediate (chemical mediators) or delayed (cellular infiltration) inflammatory response, or by alteration of the membrane integrity. This later can be transient (hyperosmolar BBB disruption), or permanent by activation of matrix metalloproteinase or by neovascularization with BBB breakdown. The reference method for the diagnosis of vasogenic oedema is the MRI diffusion-weighted imaging.
Blood-Brain Barrier↗
[Interpretation of chest radiographs in the intensive care unit: a hard- versus soft-copy comparative study].
PURPOSE: To compare the reliability of hard- versus soft-copy interpretation of intensive care unit chest radiographs, using a non-specialized standard resolution computer screen. MATERIALS AND METHODS: 104 chest radiographs were included in this study. Three physicians (one radiology resident, one intensive care unit resident and one experienced intensive care unit physician) gave their interpretations on computerized grids. Results were analyzed statistically using ROC curves and Kappa (kappa) index of concordance with experts. RESULTS: Results for reanimation equipment detection are almost independent from the modality (kappa(soft-copy)=0.891+/-0.037, kappa(hard-copy)=0.899+/-0.037). Regarding pathology detection, a global analysis only shows a difference at the limits of significance to the advantage of hard-copy films (kappa(soft)=0.514 +/-0.028, kappa(hard)=0.572+/-0.028). Overall results were significantly better for the radiologist compared to the intensive care unit physicians (kappa(radiologist)=0.751+/-0.048, kappa(intensive-care)=0.405+/-0.048). CONCLUSION: Concerning the task that is studied here, which requires only routine computer equipment, our results suggest that human factors can be more important than material factors.
Data Interpretation, Statistical↗
Assessing pain in critically ill sedated patients by using a behavioral pain scale.
OBJECTIVE: To establish the validity and reliability of a new behavioral pain scale (BPS) for critically ill sedated adult patients. DESIGN: Prospective evaluation. SETTING: Ten-bed trauma and surgical intensive care unit in a university teaching hospital. PATIENTS: Thirty mechanically ventilated patients who were receiving analgesia and sedation. INTERVENTION: Assessments with the BPS were completed consecutively at standardized times (morning, afternoon, night) by pairs of evaluators (nurse and nurse's aide). They collected physiologic parameters and BPS results before and during care procedures: non-nociceptive (group 1, compression stockings application and central venous catheter dressing change), nociceptive (group 2, endotracheal suctioning and mobilization), and retested nociceptive (group 3). The BPS score was the sum of three items that had a range score of 1-4: facial expression, movements of upper limbs, and compliance with mechanical ventilation. MEASUREMENTS AND MAIN RESULTS: Two hundred and sixty nine assessments were completed, including 104, 134, and 31 measurements in groups 1, 2 and 3, respectively. There was no difference in Ramsay scale scores between the three groups (Ramsay 4-6). Nociceptive stimulations (group 2) resulted in significantly higher BPS values than non-nociceptive ones (group 1, 4.9 vs. 3.5, p <.01), whereas the two groups had comparable BPS values before stimulation (3.1 vs. 3.0). A trend was found in group 2 between the dosage of sedation/analgesia and BPS: the higher the dosage, the lower BPS values and BPS changes to nociceptive stimulation. Group 3 had BPS values similar to group 2 at rest (3.2 vs. 3.2) and during the procedure (4.4 vs. 4.5), with good interrater correlations (r(2) =.71 and.50, respectively). CONCLUSIONS: These results indicate that the expression of pain can be scored validly and reliably by using the BPS in sedated, mechanically ventilated patients. Further studies are warranted regarding the utility of the BPS in making clinical decisions about the use of analgesic drugs in the intensive care unit.
Adult↗
[Current treatment of closed injuries of the liver: benefits and pitfalls].
STUDY AIM: The management of blunt hepatic trauma has been modified by the development of conservative methods. Risks and pitfalls of this new approach must be determined. PATIENTS AND METHODS: From January 1985 to September, 1998, 130 patients with blunt hepatic trauma were treated by the same team. Among them, 38 patients were referred from another centre (21 already having undergone operations). Eighty patients (61%) had an initial non operative management and 50 patients (39%) underwent emergency laparotomy. Perihepatic packing was performed in 24 patients, hepatic sutures in 22, limited hepatic resection in six, and major hepatectomy in two patients only. RESULTS: There were three deaths in the non operative management group (mortality rate: 3.5%) and 11 patients required a secondary laparotomy: four for haemorrhage, one for enteric injury, two for acute pancreatitis, one for bile leakage, one for subphrenic abscess, one for acute cholecystitis. There were 14 deaths in the emergency laparotomy group (mortality rate: 28%), including four intraoperative deaths due to haemorrhage and two due to abdominal compartment syndrome. CONCLUSIONS: In the nonoperative management group a close clinical survey of the patient is necessary and a secondary laparotomy often indicated. In the operative management group, early packing requires reintervention if the patient is unstable. Alternative means of temporary closure may allow coverage without tension in order to avoid the abdominal compartment syndrome.
Adolescent↗
[Aortic diverticulum: differential diagnosis of traumatic lesions of the thoracic aorta].
We report the case of a 31-year-old patient with a chest trauma after a mountaineering accident. Contrast enhanced spiral computed tomography of the thorax showed a lesion of the aortic isthmus, suspected of being an aortic disruption. As the diagnosis of aortic rupture could not be formally established with computed tomography, a transoesophageal echocardiography and an aortic angiography were performed which showed a ductus diverticulum, representing one of the differential diagnoses of traumatic aortic disruption. A knowledge of this entity and its diagnostic criteria may avoid an unnecessary thoracotomy.
Adult↗
[Effect of peroperative analgesia on immediate postoperative oxygen consumption].
Oxygen consumption in the immediate postoperative period was assessed in a series of twelve patients undergoing maxillofacial surgery, randomly assigned to two groups (n = 6 for each). The anaesthetic protocol was the same in all patients: premedication with flunitrazepam 30 micrograms.kg-1, induction with flunitrazepam 20 micrograms.kg-1, fentanyl 5 micrograms.kg-1, thiopentone 5 mg.kg-1, pancuronium bromide 80 micrograms.kg-1, and maintenance during the first three hours with flunitrazepam 10 micrograms.kg-1.h-1 and pancuronium 0.03 micrograms.kg-1.h-1. All the patients were given a continuous infusion of fentanyl during the whole length of the surgery: in Group I (GI), 3 micrograms.kg-1.h-1 and in Group II (GII), 1 microgram.kg-1.h-1. The patients in Group II were also given enflurane 1.2 +/- 0.3 vol %. During the immediate postoperative period, the parameters studied were measured by means of an Engström Metabolism Calculator at the 15th, 30th, 45th, 60th, 120th and 240th minutes, and at the time of extubation. In GII, postoperative heart rate and lactic acid levels were higher than in GI (p less than 0.05). Both groups had oxygen consumption values greater than theoretical resting levels. However, postoperative oxygen consumption was greatly increased in GII with respect to GI during the first 4 hours (p less than 0.01). The respiratory quotient was greater in GI than in GII at the end of the study (p less than 0.05). These data indicate that the intraoperative analgesic technique influences postoperative oxygen consumption. A dose of fentanyl of 3 micrograms.kg-1.h-1 is more efficient than one of 1 microgram.kg-1.h-1 associated with enflurane.
Adult↗
[Systemic air embolism after CT-guided transthoracic biopsy using a cutting needle].
The authors report a case of systemic air embolism after CT-guided transthoracic needle biopsy using an 18G cutting needle. CT performed immediately after the occurrence of neurological signs showed air within the left ventricle but no air within the cerebral arteries. Radiologists must be aware of this extremely rare but potentially severe complication to provide accurate diagnosis and treatment.
Biopsy, Needle↗