Sevoflurane sedation in infants--a fine line between sedation and general anesthesia

Wdr5-mediated H3K4me3 coordinately regulates cell differentiation, proliferation termination, and survival in digestive organogenesis

Food digestion requires the cooperation of different digestive organs. The differentiation of digestive organs is crucial for larvae to start feeding. Therefore, during digestive organogenesis, cell identity and the tissue morphogenesis must be tightly coordinated but how this is accomplished is poorly understood. Here, we demonstrate that WD repeat domain 5 (Wdr5)-mediated H3K4 tri-methylation (H3K4me3) coordinately regulates cell differentiation, proliferation and apoptosis in zebrafish organogenesis of three major digestive organs including intestine, liver, and exocrine pancreas. During zebrafish digestive organogenesis, some of cells in these organ primordia usually undergo differentiation without apoptotic activity and gradually reduce their proliferation capacity. In contrast, cells in the three digestive organs of wdr5^-/- mutant embryos retain progenitor-like status with high proliferation rates, and undergo apoptosis. Wdr5 is a core member of COMPASS complex to implement H3K4me3 and its expression is enriched in digestive organs from 2 days post-fertilization (dpf). Further analysis reveals that lack of differentiation gene expression is due to significant decreases of H3K4me3 around the transcriptional start sites of these genes; this histone modification also reduces the proliferation capacity in differentiated cells by increasing the expression of apc to promote the degradation of β-Catenin; in addition, H3K4me3 promotes the expression of anti-apoptotic genes such as xiap-like, which modulates p53 activity to guarantee differentiated cell survival. Thus, our findings have discovered a common molecular mechanism for cell fate determination in different digestive organs during organogenesis, and also provided insights to understand mechanistic basis of human diseases in these digestive organs.

Needle-free pharmacological sedation techniques in paediatric patients for imaging procedures: a systematic review and meta-analysis

BACKGROUND

Sedation techniques and drugs are increasingly used in children undergoing imaging procedures. In this systematic review and meta-analysis, we present an overview of literature concerning sedation of children aged 0-8 yr for magnetic resonance imaging (MRI) procedures using needle-free pharmacological techniques.

METHODS

Embase, MEDLINE, Web of Science, and Cochrane databases were systematically searched for studies on the use of needle-free pharmacological sedation techniques for MRI procedures in children aged 0-8 yr. Studies using i.v. or i.m. medication or advanced airway devices were excluded. We performed a meta-analysis on sedation success rate. Secondary outcomes were onset time, duration, recovery, and adverse events.

RESULTS

Sixty-seven studies were included, with 22 380 participants. The pooled success rate for oral chloral hydrate was 94% (95% confidence interval [CI]: 0.91-0.96); for oral chloral hydrate and intranasal dexmedetomidine 95% (95% CI: 0.92-0.97); for rectal, oral, or intranasal midazolam 36% (95% CI: 0.14-0.65); for oral pentobarbital 99% (95% CI: 0.90-1.00); for rectal thiopental 92% (95% CI: 0.85-0.96); for oral melatonin 75% (95% CI: 0.54-0.89); for intranasal dexmedetomidine 62% (95% CI: 0.38-0.82); for intranasal dexmedetomidine and midazolam 94% (95% CI: 0.78-0.99); and for inhaled sevoflurane 98% (95% CI: 0.97-0.99).

CONCLUSIONS

We found a large variation in medication, dosage, and route of administration for needle-free sedation. Success rates for sedation techniques varied between 36% and 98%.

Sevoflurane for central catheter placement in neonatal intensive care: a randomized trial

OBJECTIVE

To compare the efficacy and safety of sevoflurane deep sedation with glucose and nonnutritive sucking (GNNS) in reducing the duration of the procedure and in preventing pain-related effects during peripherally inserted central catheter (PICC) placement.

BACKGROUND

PICC placement in neonatal intensive care is a delicate and stressful procedure that requires pain prevention. GNNS has been recommended in this situation but remain often inefficient.

METHODS

We designed a randomized controlled study in a sixteen-bed pediatric and neonatal unit in a tertiary hospital. Fifty-nine neonates at >28 weeks of gestation with continuous positive airway pressure or invasive mechanical ventilation and requiring PICC placement were included. Patients were randomized to receive inhaled sevoflurane (IS) or glucose and non-nutritive sucking (GNNS). Procedural duration and conditions, hemodynamic and respiratory parameters, occurrence of movements and complications were compared (http://clinicaltrials.gov trial register no. NCT00420693).

RESULTS

The two groups had similar demographics. There were no between-group differences in procedural duration (P = 0.84) despite greater immobility in IS group (P = 0.017). IS was also associated with fewer episodes of hypertension (P = 0.003), tachycardia (P < 0.001), and bradycardia (P = 0.02). Occurrences of hypotension were not different between the groups (P = 0.06). The GNNS group showed more desaturation during the 4 h after the procedure (P = 0.03). Complications during intensive care stay did not differ between groups.

CONCLUSION

Inhaled sevoflurane does not make easier catheters placement but prevent pain-related symptoms. Because sevoflurane is responsible for hypotension, it requires careful monitoring and treatment adaptation.

[Sedation with sevoflurane for magnetic resonance imaging in pediatrics: retrospective study of 5864 cases]

OBJECTIVE

To evaluate the use of sevoflurane for sedating pediatric patients undergoing magnetic resonance imaging studies.

MATERIAL AND METHODS

Data were extracted retrospectively from the records of 5864 pediatric patients (aged 0-18 years) who had undergone magnetic resonance imaging studies in our hospital from 1999 to 2004. Sevoflurane was usually administered at high concentrations of up to 7% on induction; after 2 minutes the concentration was reduced. The patient, breathing spontaneously, was kept sedated with a sevoflurane concentration of 1.5% to 2% in a mixture of 50% nitrous oxide and 50% oxygen.

RESULTS

Optimal sedation was achieved in 5789 (98.72%) of the cases treated. Complications included 11 episodes of vomiting, 53 cases (0.9%) of mild respiratory depression, 6 cases of severe respiratory depression on induction, and 5 cases of agitation. There were no cases of prolonged sedation.

CONCLUSION

Sevoflurane is useful for sedating pediatric patients in the setting of this study. Induction is rapid and gentle, and maintained sedation is constant, stable and homogeneous. Awakening and recovery are rapid, and the incidence of complications low.

Sevoflurane for central venous catheterization in non-intubated neonates

OBJECTIVE

Sedation in neonates undergoing invasive prodedures as central venous catheterization (CVC) remains contro versial. Sevoflurane is an inhaled anesthetic whose periods of action and elimination are very short. The objective of this study was to evaluate the use of sevoflurane for sedation for central venous catheterization (CVC) in non-intubated neonates and preterms.

METHODS

Thirty three (33) consecutive patients (range: 1-31 days old, 26 to 40 weeks GA, weighing 580 to 3200 g) were included over a 4 months period. Sevoflurane was progressively increased, until loss of consciousness and motor response to stimulation. FiO(2), heart rate (HR), mean arterial pressure (MAP), duration of the procedure and the ease of the procedure were recorded.

RESULTS

HR was very stable, but MAP dropped significantly. No patient required intubation. The ease of the procedure was scored as average 13 times and excellent 20 times.

CONCLUSION

The use of sevoflurane in neonates for CVC is feasible and achieve the goals of procedural sedation. The pharmacokinetic of sevoflurane enabled rapid adjustment of the depth of sedation. Sevoflurane appears to be a new agent at the disposal of neonatologists. Its use does not come without risks, especially for smaller preterms, which the treating clinician must anticipate.

Sedation during regional anesthesia: inhalation versus intravenous

PURPOSE OF REVIEW

Sedation of patients either with or without regional anesthesia is discussed to ascertain sedation requirements in the two groups. The differences between 'monitored anesthesia care' and conscious sedation are defined. Several current and promising methods with which we can evaluate a patient's degree or level of sedation are assessed. Also noted are safety concerns regarding monitoring solutions for patients undergoing monitored anesthesia care. Well established techniques, including some which are decidedly 'low tech', are examined. Several routes of intravenous administration are discussed along with patient variables. Sevoflurane sedation is mentioned with regards to administration, advantages and drawbacks.

RECENT FINDINGS

Several modalities have been studied for evaluation of a patient's level of sedation, some of which have little applicability in the operating room. Processed electroencephalographic monitoring has tremendous promise but is currently not reliable enough to assess sedation level. Sevoflurane has a role in sedation, providing the limitations are understood. One drawback of sevoflurane is its greater degree of disinhibition when compared with intravenous agents, necessitating conversion to general anesthesia.

SUMMARY

Evaluating the degree of patient sedation is a need that technology has yet to meet. Several techniques have been tried in intensive care units but have little utility in the operating room. Utilization of processed electroencephalogram waveforms has the greatest potential but is of limited value at the present time. Sevoflurane is demonstrated to have a limited role in sedation but may prove useful in specific circumstances.