Year in review in Intensive Care Medicine 2010: III. ARDS and ALI, mechanical ventilation, noninvasive ventilation, weaning, endotracheal intubation, lung ultrasound and paediatrics

SCOPUS: re.jinfo:eu-repo/semantics/publishe

Year in review in Intensive Care Medicine 2011: III. ARDS and ECMO, weaning, mechanical ventilation, noninvasive ventilation, pediatrics and miscellanea

SCOPUS: re.jinfo:eu-repo/semantics/publishe

Infantile major airway stenosis and acute respiratory distress associated with cardiac tamponade

Coxsackie virus pericarditis caused cardiac tamponade in a 45-day-old infant with corrected total anomalous pulmonary venous drainage and a hypodynamic left heart. The pathophysiology comprised reduced heart compliance, venous return impairment, acute pulmonary hypertension, and increased airway microvascular permeability. Tracheal edema and external compression caused tracheal lumen narrowing and respiratory failure. Laryngoscopy was difficult because of laryngeal inlet swelling. Endotracheal intubation was accomplished with a 3.0-mm tube. Pericardial cavity evacuation resulted in rapid recovery. A postprocedural chest radiograph revealed tracheal lumen enlargement. Repeated laryngoscopy revealed resolution of upperairway edema. In infants, large pericardial effusions developing after corrective/palliative heart surgery may cause major airway compromise

Prone position reduces lung stress and strain in severe acute respiratory distress syndrome

The present authors hypothesised that in severe acute respiratory distress syndrome (ARDS), pronation may reduce ventilator-induced overall stress (i.e. transpulmonary pressure (PL)) and strain of lung parenchyma (i.e. tidal volume (VT)/end-expiratory lung volume (EELV) ratio), which constitute major ventilator-induced lung injury determinants. The authors sought to determine whether potential pronation benefits are maintained in post-prone semirecumbent (SRPP) posture under pressure-volume curve-dependent optimisation of positive end-expiratory pressure (PEEP). A total of 10 anesthetised/paralysed, mechanically ventilated (VT=9.0+/-0.9 mL(.)kg(-1) predicted body weight; flow=0.91 +/- 0.04 L(.)s(-1); PEEP=9.4 +/- 1.3 cmH(2)O) patients with early/severe ARDS were studied in pre-prone semirecumbent (SRBAS), prone, and SRPP positions. Partitioned respiratory mechanics were determined during iso-flow (0.91 L(.)s(-1)) experiments (VT varied within 0.2-1.0 L), along with haemodynamics, gas exchange, and EELV. Compared with SRBAS, pronation/SRPP resulted in reduced peak/plateau PL at VTS greater than or equal to 0.6 L; static lung elastance and additional lung resistance decreased and chest wall elastance (in prone position) increased; EELV increased (23-33%); VT/EELV decreased (27-33%); arterial oxygen tension/inspiratory oxygen fraction and arterial carbon dioxide tension improved (21-43/1014%, respectively), and shunt fraction/physiological dead space decreased (21-50/20-47%, respectively). In early/severe acute respiratory distress syndrome, pronation under positive end-expiratory pressure optimisation may reduce ventilator-induced lung injury risk. Pronation benefits may be maintained in post-prone semirecumbent position

Prone position improves expiratory airway mechanics in severe chronic bronchitis

Based on lung parenchyma-airways’ interdependence, the present authors hypothesised that prone positioning may reduce airway resistance in severe chronic bronchitis. A total of 10 anaesthetised/mechanically ventilated patients were enrolled. Partitioned respiratory system (RS) mechanics during iso-flow experiments (flow=0.91 L(.)s(-1), tidal volume (VT) varied within 0.2-1.2 L), haemodynamics, gas-exchange, expiratory airway resistance (Raw,exp), functional residual capacity (FRC), change in FRC (DeltaFRC), end-expiratory lung volume (EELV), expiratory airway resistance at EELV (Raw,exp,EELV), intrinsic positive end-expiratory pressure (PEEPi), and mean end-expiratory flow were determined in baseline semirecumbent (SRBAS), prone, and post-prone semirecumbent (SRPP) postures. Pronation versus SRBAs resulted in significantly reduced Raw,exp (at VT greater than or equal to0.8 L), Raw,exp,EELV (18.3+/-1.4 versus 31.6+/-2.6 cm H2O.L(-1.)s(-1)), inspiratory airway resistance (at VT greater than or equal to1.0 L), static lung elastance (at VT less than or equal to0.6 L), “additional” RS/lung resistance (at a range of VTS), DeltaFRC (0.35+/-0.03 versus 0.47+/-0.03 L), EELV (4.92+/-0.49 versus 5.65+/-0.65 L), RS/lung PEEPi (6.7+/-1.1/5.4+/-0.6 versus 8.9+/-1.7/7.8+/-1.1 cm H2O), mean end-expiratory flow (63.9+/-4.2 versus 47.9+/-4.0 mL(.)s(-1)), and shunt fraction (0.16+/-0.03 versus 0.21+/-0.03); benefits were reversed in SRPP. In severe chronic bronchitis, prone positioning reduces airway resistance and dynamic hyperinflation

Static pressure volume curves and body posture in acute respiratory failure

Objective: In acute respiratory distress syndrome the body posture effects on pressure-volume (PV) curves are still unclear. We examined the effects of prone position on inflation PV curves and their potential relationships with postural alterations in gas exchange. Design and setting: Prospective study with patients serving as their own controls in a university-affiliated 30-bed intensive care unit. Patients and participants: Thirteen anesthetized, paralyzed, semirecumbent, mechanically ventilated patients with early/severe/diffuse ARDS. Interventions: Sequential body posture changes: preprone semirecumbent, prone, and postprone semirecumbent. Measurements and results: In each posture hemodynamics, gas exchange, and lung volumes were determined before/during removal and after restoration of positive end-expiratory pressure ( PEEP=10.2 +/- 0.6 cmH(2)O). At zero PEEP PV curves of respiratory system, lung, and chest wall were constructed. Prone position vs. preprone semirecumbent resulted in significantly reduced pressure lower inflection point of lung PV curve (2.2 +/- 0.2 vs. 3.7 +/- 0.5 cmH(2)O) and increased volume at upper inflection point (0.87 +/- 0.03 vs. 0.69 +/- 0.051). Postural reduction in lower inflection point pressure of lung PV curve was the sole independent predictor of pronation-induced increases in PaO2/FIO2 (R-2 = 0.76). PaO2/FIO2 increases were also significantly related with increases in functional residual capacity (R-2 = 0.60). Conclusions: In early/severe/diffuse ARDS prone position reduces lower inflection point pressure and increases upper inflection point UIP volume of the lung PV curve. Lower inflection point pressure reductions explain oxygenation improvements, which are also associated with a postural increase in functional residual capacity