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Biomedical subjects

Isabelle Constant

Publications and source records attributed to Isabelle Constant.

7 recordsLinked to original sources
PubMed2006

Noninvasive investigation of autonomic activity after carotid stenting or carotid endarterectomy.

OBJECTIVE: Carotid artery stenting (CAS) has been introduced as an alternative to carotid endarterectomy (CEA) for the treatment of carotid artery stenosis. Both techniques seem to be associated with postoperative hemodynamic lability. Both may induce baroreceptor dysfunction, possibly leading to transient impairment of cardiovascular autonomic activity and resulting in hemodynamic instability. This instability might contribute to postoperative morbidity. To elucidate these phenomena, we studied the cardiac baroreflex and autonomic cardiovascular control after CAS and CEA. METHOD: In 20 patients scheduled for CAS (n = 10) or CEA (n = 10), intra-arterial pressures and electrocardiograms were recorded during 10 minutes before and 8 and 24 hours after the procedure. Spontaneous cardiac baroreflex sensitivity was assessed using the sequence method and cross-spectral analysis. In addition, cardiovascular autonomic activity was investigated using spectral analysis of heart rate variability and systolic arterial pressure variability. RESULTS: After CAS, we demonstrated an increase of the spontaneous baroreflex sensitivity median (interquartile range) from 5.6 (5.1 to 6.2) ms/mm Hg before the procedure to 8.8 (6.8 to 10.5) ms/mm Hg and 7.7 (3.9 to 8.6) ms/mm Hg (P < .001), 8 and 24 hours after the procedure. This was consistent with the increase of the high frequency component of heart rate variability reflecting cardiac parasympathetic activity and a decrease of the low frequency of systolic arterial pressure variability reflecting sympathetic vascular activity. The postoperative period was also associated with decreased systolic arterial pressure from 173 (162 to 190) mm Hg at baseline to 122 (109 to 143) mm Hg and 136 (121 to 143) mm Hg at 8 and 24 hours after CAS (P < .001). No changes in baroreflex sensitivity or in autonomic activity were observed after CEA. CONCLUSIONS: These preliminary data suggest that CAS is associated with parasympathetic predominance postoperatively and may probably explain the lower systolic arterial pressure observed after CAS.

Aged↗
PubMed2005

Inhalational anesthetics in pediatric anesthesia.

PURPOSE OF REVIEW: The purpose of this review is to discuss interesting recent developments concerning the use of halogenated agents. Now we are in a new stage of halogen use; we have become alerted to the secondary effects which although not life-threatening are potentially deleterious. RECENT FINDINGS: The recent literature highlighted some unexpected effects with the use of new halogens such as emergence agitation associated with rapid elimination of new anesthetics, or epileptogenic effect of sevoflurane. In addition, recent advances in monitoring of depth of anesthesia may contribute to a more-precise dosing of halogens and concomitant decrease of the deleterious side effects. SUMMARY: Based on this new approach, the therapeutic range of the new halogenated agents may be revisited and possibly narrowed.

Journal Article↗
PubMed2005

Sevoflurane and epileptiform EEG changes.

Sevoflurane has become the volatile agent of choice for inhalation induction of anesthesia. Hemodynamic stability and lack of respiratory irritation have justified its rapid extension to pediatric inhalation induction. The epileptogenic potential of sevoflurane has been suspected since the first case reports of abnormal movements in children without a history of epilepsy. The objectives of this short review are to: (i) analyze clinical and electroencephalographic (EEG) features supporting epileptogenic activity of sevoflurane, (ii) identify factors which may modulate that activity, and (iii) suggest guidelines of clinical practice to limit expression of this epileptiform phenomenon, which has thus far unknown morbidity. The use of sevoflurane may be associated with cortical epileptiform EEG signs, usually without clinical manifestation. No lasting neurological or EEG sequelae have been described thus far, and the potential morbidity of this epileptogenic effect is unknown. The use of sevoflurane in children, with its remarkable cardiovascular profile, should include a number of precautions. Among them, the limitation of the depth of anesthesia is essential. The wide use of cerebral function monitoring (the most simple being the EEG), may permit optimization of sevoflurane dose and avoidance of burst suppression and major epileptiform signs in fragile subjects, notably the very young and the very old.

Adult↗
PubMed2004

Perioperative anaesthetic morbidity in children: a database of 24,165 anaesthetics over a 30-month period.

BACKGROUND: This study reports the practices and morbidity of 24,165 anaesthetics performed over a 30-month period in a paediatric teaching hospital. METHODS: Data describing practices and adverse events during anaesthesia and in the postanaesthesia care unit (PACU) were collected prospectively from 1 January 2000 to 30 June 2002 on an audit form as a part of the Quality Assurance Program. All surgical specialties are covered except for open heart surgery and neurosurgery. RESULTS: A total of 724 adverse events were reported during anaesthesia and 1105 in PACU. Respiratory events represented 53% of all intraoperative events. They were more frequent in infants compared with older children, in ENT surgery compared with other surgery, in children in whom the trachea was intubated and in children with ASA status 3-5 compared with those with ASA score 1 or 2. Cardiac events accounted for 12.5% of intraoperative events and were mainly observed in children with ASA score 3-5. In PACU, vomiting was the most frequent adverse event with an overall incidence of 6%. Vomiting was more frequent in older children compared with infants and young children and more frequent after ENT surgery compared with other surgery. Only one death was reported in a premature newborn infant and was not anaesthesia-related. CONCLUSIONS: This observational study confirms previous reports, and indicates that there is still a relative higher rate of adverse events in infants compared with older children even in a teaching paediatric hospital with a high annual caseload.

Adolescent↗
PubMed2004

Does halothane really preserve cardiac baroreflex better than sevoflurane? A noninvasive study of spontaneous baroreflex in children anesthetized with sevoflurane versus halothane.

Heart rate profiles during the induction of anesthesia differ markedly between the administration of sevoflurane and halothane. Previous investigations have shown that halothane preserves cardiac parasympathetic activity more than sevoflurane. Because vagal drive to the sinus node is the main effector of arterial baroreflex control of heart rate, halothane may preserve cardiac baroreflex better than sevoflurane. To investigate cardiac baroreflex in anesthetized children, we used two noninvasive methods providing different approaches to the arterial blood pressure (BP) and R-R interval (RRI) relationship: the sequence methods investigating beat-to-beat changes in BP and RRI (time domain) and the cross-spectral analysis investigating relationships between oscillations of BP and RRI (frequency domain). Children were randomly assigned to mask induction with sevoflurane in 100% oxygen, sevoflurane in 50% nitrous oxide/50% oxygen, or halothane in 50% nitrous oxide/50% oxygen. After tracheal intubation, the inspired fraction of volatile anesthetic was reduced to 1 minimum alveolar anesthetic concentration (MAC). The spontaneous baroreflex (SBR) sensitivity was calculated with the sequence method at baseline, during induction, and after intubation. The cardiac baroreflex was also estimated with cross-spectral analysis at baseline and at 1 MAC (stationary conditions). In the three groups, the induction of anesthesia was associated with a marked decrease of SBR sensitivity, which occurred earlier with sevoflurane than with halothane. Five minutes after intubation (1 MAC), the sequence method showed a similar decrease of the SBR sensitivity in the three groups. Similarly, the cross-spectral analysis between systolic blood pressure and RRI showed a decrease of the gain calculated in the low-frequency band, but the gain in the respiratory band was higher with halothane compared with sevoflurane. In children, the induction of anesthesia with halothane and sevoflurane is associated with a marked decrease of cardiac baroreflex activity. The persistence of respiratory RRI fluctuations under halothane might reflect reflex respiratory arrhythmia rather than efficient parasympathetic baroreflex activity.

Anesthetics, Inhalation↗