A tiny baby intubation team improves endotracheal intubation success rate but decreases residents' training opportunities.

OBJECTIVE: To assess the educational and clinical impact of a tiny baby intubation team (TBIT). STUDY DESIGN: Retrospective study comparing endotracheal intubation (ETI) performed: pre-implementation of a TBIT (T1), 6 months post-implementation (T2), and 4 years post-implementation (T3). RESULTS: Post-implementation (T2), first-attempt success rate in tiny babies increased (44% T1; 59% T2, p = 0.04; 56% T3, p = NS) and the proportion of ETIs performed by residents decreased (53% T1; 37% T2, p = 0.001; 45% T3, p = NS). After an educational quality improvement intervention (prioritizing non-tiny baby ETIs to residents, systematic simulation training and ETI using videolaryngoscopy), in T3 residents' overall (67% T1; 60% T2, p = NS; 79% T3, p = 0.02) and non-tiny baby ETI success rate improved (72% T1; 60% T2, p = NS; 82% T3, p = 0.02). CONCLUSION: A TBIT improves success rate of ETIs in ELBW infants but decreases educational exposure of residents. Educational strategies may help maintain resident procedural competency without impacting on quality of care.

Site of phrenic nerve stimulation-induced upper airway collapse: influence of expiratory time.

Electrical phrenic nerve stimulation (EPNS) applied at end expiration during exclusive nasal breathing can be used to characterize upper airway (UA) dynamics during wakefulness by dissociating phasic activation of UA and respiratory muscles. The UA level responsible for the EPNS-induced increase in UA resistance is unknown. The influence of the twitch expiratory timing (200 ms and 2 s) on UA resistance was studied in nine normal awake subjects by looking at instantaneous flow, esophageal and pharyngeal pressures, and genioglossal electromyogram (EMG) activity during EPNS at baseline and at -10 cmH(2)O. The majority of twitches had a flow-limited pattern. Twitches realized at 200 ms and 2 s did not differ in their maximum inspiratory flows, but esophageal pressure measured at maximum inspiratory flow was significantly less negative with late twitches (-6.6 +/- 2.7 and -5.0 +/- 3.0 cmH(2)O respectively, P = 0.04). Pharyngeal resistance was higher when twitches were realized at 2 s than at 200 ms (6.4 +/- 2.4 and 2.7 +/- 1.1 cmH(2)O x l(-1). s, respectively). EMG activity significant rose at peak esophageal pressure with a greater increase for late twitches. We conclude that twitch-induced UA collapse predominantly occurs at the pharyngeal level and that UA stability assessed by EPNS depends on the expiratory time at which twitches are performed.

Low stomatal and internal conductance to CO2 versus Rubisco deactivation as determinants of the photosynthetic decline of ageing evergreen leaves.

A novel A-Ci curve (net CO2 assimilation rate of a leaf -An- as a function of its intercellular CO2 concentration -Ci) analysis method (Plant, Cell & Environment 27, 137-153, 2004) was used to estimate the CO2 transfer conductance (gi) and the maximal carboxylation (Vcmax) and electron transport (Jmax) potentials of ageing, non-senescing Pseudotsuga menziesii leaves in relation to their nitrogen (N) content and protein and pigment composition. Both gi and the stomatal conductance (gsc) of leaves were closely coupled to Vcmax, Jmax and An with all variables decreasing with increasing leaf age. Consequently, both Ci and Cc (chloroplastic CO2 concentration) remained largely conserved through successive growing seasons. The N content of leaves, as well as the amount of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and other sodium dodecyl sulfate-soluble proteins, increased during the first three growing seasons, then stabilized or decreased only slightly afterwards. Thus, the age-related photosynthetic nitrogen use efficiency (PNUE) decline of leaves was not a consequence of decreased allocation of N towards Rubisco and other proteins involved in bioenergetics and light harvesting. Rather, loss of photosynthetic capacity was the result of the decreased activation state of Rubisco and proportional down-regulation of electron transport towards the photosynthetic carbon reduction (PCR) and photorespiratory (PCO) cycles in response to a reduction of CO2 supply to the chloroplasts' stroma. This study emphasizes the regulatory potential and homeostaticity of Cc- rather than photosynthetic metabolites or Ci- in relation to the commonly observed correlation between photosynthesis and gsc.