Daily nursing care on patients undergoing venous-venous extracorporeal membrane oxygenation: a challenging procedure!

Daily nursing in critical care patients may alter vital parameters, especially in the most critically ill patients. The aim of our study was to evaluate feasibility and safety of daily nursing on patients undergoing venous-venous extracorporeal membrane oxygenation (vv-ECMO) for severe respiratory failure. Daily nursing was performed following defined phases (sponge bath, elevation with scooping stretcher, change position of endotracheal tube, dressing replacement). We recorded physiological and ECMO parameters before and during daily nursing in 5 patients for several days (total: 25 daily nursing) and adverse events: desaturation, hypertension, reduction of mixed venous oxygen saturation, arterial oxygen saturation or ECMO blood flow and elevation in minute ventilation. Sedative drug dosage and additional bolus were recorded. Daily nursing was performed in 92 % of cases (23/25), with a minimum of two adverse events per daily nursing. Hypertension and tachycardia were mostly recorded at the beginning, while desaturation, reduction in mixed venous oxygen saturation and blood flow were recorded during elevation with scooping stretcher. Increase in minute ventilation was frequent in spontaneous breathing patients. Additional bolus of sedation was required before and/or during nursing. Daily nursing significantly alters physiologic parameters; thus, it should be performed only when physicians are readily available to treat adverse events.

Pure anti-tumor effect of zoledronic acid in naïve bone-only metastatic and locally advanced breast cancer: proof from the "biological window therapy".

The study investigated the anti-tumour effect of zoledronic acid (ZA) administered alone in a biological window therapy in naïve bone-only metastatic and locally advanced breast cancer (LABC) patients. 33 patients with LABC (Group 1) and 20 patients with a first diagnosis of bone metastasis only (Group 2) received 4 mg single dose of ZA, 14 days (biological window) before starting any treatment. In Group 1, Ki67, CD34, p53/bcl-2 and caspase 3 expression along with the adenosine triphosphate (ATP) levels and RNA disruption index were evaluated as markers of tumor growth in tumour specimens obtained before and after ZA administration (basal, day 14). In Group 2, the total enumeration of circulating tumour cells (CTCs), and of M30+ve CTCs along with the soluble marker of cell death (M30/M65) were carried-out as markers of tumor dissemination at baseline, at 48 h and day 14th. In Group 1, there was a significant reduction in Ki67, CD34, bcl-2 expression after 14 days ZA based-treatment (p = 0.0032; p = 0.0001, p < 0.00001 respectively). ZA showed a significant increase of RNA disruption (p < 0.0076). In Group 2, we observed a significant reduction of CTCs number after 48 h (p = 0.0012), followed by a significant rebound at 14 days (p = 0.012). The apoptotic CTCs/M30+ve and M65 levels significantly increased under treatment (p = 0.018 and p = 0.039 respectively) after drug administration when compared to the baseline. These results are the first prospective in vivo data showing the direct pure anti-tumour effect (either on the tumour cell or on CTCs) of ZA.

Respiratory pattern during neurally adjusted ventilatory assist in acute respiratory failure patients.

PURPOSE: To investigate the effect of a wide range of assistance levels during neurally adjusted ventilatory assist (NAVA) and pressure support ventilation (PSV) on respiratory pattern, breathing variability, and incidence of tidal volumes (V (T)) above 8 and 10 ml/kg in acute respiratory failure patients. METHODS: Eight increasing NAVA levels (0.5, 1, 1.5, 2, 2.5, 3, 4, and 5 cmH(2)O/µV) and four increasing pressure support (PSV) levels (4, 8, 12, and 16 cmH(2)O) were applied to obtain 10 min of stable recordings in 15 patients. RESULTS: One out of 15 patients did not sustain the NAVA levels of 3, 4, and 5 cmH(2)O/µV and was excluded. The 5 cmH(2)O/µV NAVA level was not tolerated by three patients and it was excluded. Increasing NAVA levels were associated with decreased diaphragm electrical activity (EAdi), and, at variance with PSV, with small changes in V (T), no changes in respiratory rate (RR), and increases in V (T) and EAdi variability. At high NAVA levels, an increase in V (T) variability was associated with increased incidence of V (T) above 8 and 10 ml/kg and an uncomfortable respiratory pattern in some patients. CONCLUSIONS: Increasing NAVA levels were associated with no effect on RR, small increase in V (T), and increase in V (T) and EAdi variability. Effective decrease in EAdi occurred at NAVA levels below 2-2.5 cmH(2)O/µV, while preserving respiratory variability and low risks of V (T) above 8 or 10 ml/kg.

Extracorporeal membrane oxygenation for interhospital transfer of severe acute respiratory distress syndrome patients: 5-year experience.

PURPOSE: Transfer of severely hypoxic patients is a high-risk procedure. Extracorporeal membrane oxygenation (ECMO) allows safe transport of these patients to tertiary care institutions. Our ECMO transportation program was instituted in 2004; here we report results after 5 years of activity. METHODS: This is a clinical observational study. Criteria for ECMO center activation were: potentially reversibile respiratory failure, PaO2 <50 mmHg with FiO2 >0.6 for >12 hours, PEEP >5 cmH20, Lung Injury Score (LIS) ≥3 or respiratory acidosis with pH <7.2, no intracranial bleeding, and no absolute contraindication to anticoagulation. If eligible, a skilled crew applied ECMO at the referral hospital. Transportation was performed with a specially equipped ambulance. RESULTS: Sixteen patients were possible candidates for ECMO transfer. Two patients were excluded while 14 (mean±SD, age 35.4±18.6, SOFA 8.4±3.7, Oxygenation Index 43.7±13.4) were transported to our institution (distance covered 102±114 km, global duration of transport 589±186 minutes). Two patients improved after iNO-trial and were transferred and subsequently managed without ECMO. The remaining 12 patients were transferred on veno-venous ECMO with extracorporeal blood flow 2.7±1 L·min⁻¹, gas flow 3.8±1.8 L·min⁻¹, and FiO2 1. Data were recorded 30 minutes before and 60 minutes after initiation of ECMO. ECMO improved PCO2 (75±23 vs. 53±9 mmHg, p<0.01) thus improving pH (7.28±0.13 vs. 7.39±0.05, p<0.01) and allowing a reduction in respiratory rate (35±14 vs. 10±4 breaths/min, p<0.01), minute ventilation (10.1±3.8 vs. 3.7±1.7 L·min⁻¹, p<0.01), and mean airway pressure (26±6.5 vs. 22±5 cmH2O, p<0.01). No major clinical or technical complications were observed. CONCLUSIONS: ECMO effectively enabled high-risk ground transfer of severely hypoxic patients.

Performance of different continuous positive airway pressure helmets equipped with safety valves during failure of fresh gas supply.

PURPOSE: We assessed the performance of different continuous positive airway pressure (CPAP) helmets equipped with a safety valve during discontinuation of fresh gas flow. METHODS: This was a physiological study of five healthy volunteers. We delivered CPAP (fresh gas flow 60 l/min, FiO(2) 60%, PEEP 5 cmH(2)O) with three different helmets in a random sequence: 4Vent (Rüsch), HelmHAR-cp (Harol) and CaStar CP210 (StarMed). For each helmet we randomly applied, for up to 4 min, three disconnections of fresh gas flow: helmet inlet (D(inlet)), flowmeter (D(flowmeter)) and gas source (D(source)). We continuously recorded from a nostril: end-tidal CO(2) (PetCO(2)), inspiratory CO(2) (PiCO(2)), fraction of inspired oxygen (FiO(2)) and respiratory rate (RR). RESULTS: During every disconnection we observed an increase in PiCO(2) and PetCO(2) with a drop in FiO(2), while RR did not change. FiO(2) decreased more quickly in the CaStar, equipped with the largest safety valve, during D(source) and D(flowmeter), while FiO(2) decreased more quickly during D(inlet) in CaStar and in 4Vent. PiCO(2) resulted in a lower increase in CaStar during D(source) and D(flowmeter) compared to 4Vent. PetCO(2) in CaStar increases more slowly compared to 4Vent during D(source) and more slowly compared to the other two helmets during D(flowmeter). During D(inlet) similar degrees of CO(2) rebreathing and PetCO(2) were recorded among all the helmets. CONCLUSIONS: To minimize CO(2) rebreathing during disconnection of the fresh gas supply while performing helmet CPAP, it is desirable to utilize large helmets with a large anti-suffocation valve. Monitoring and alarm systems should be employed for safe application of helmet CPAP.

Fluid leakage across tracheal tube cuff, effect of different cuff material, shape, and positive expiratory pressure: a bench-top study.

PURPOSE: Standard polyvinylchloride (PVC) endotracheal tube (ETT) cuffs do not protect from aspiration across the cuff, a leading cause of ventilator-associated pneumonia (VAP). In a long-lasting in vitro study we compared the effect of different cuff materials (PVC, polyurethane, and guayule latex), shapes (cylindrical, conical), and positive end expiratory pressures (PEEP) in reducing fluid leakage across the cuff. METHODS: We compared fluid leakage across a cylindrical double-layer guayule latex prototype cuff, three cylindrical PVC cuffs (Mallinckrodt Hi-Lo, Mallinckrodt HighContour, Portex Ivory), one conical PVC cuff (Mallinckrodt TaperGuard), and two polyurethane cuffs (Mallinckrodt SealGuard, conical; Microcuff, cylindrical). Ten centimeters of dyed water was poured above the cuffs inflated (pressure 30 cmH(2)O) in a vertical cylinder (diameter 20 mm). A respiratory circuit connected the bottom of the cylinder to a breathing bag inflated at four pressures (PEEP = 0, 5, 10, 15 cmH(2)O). Pictures were taken every 60 s for 24 h to measure leakage as a reduction in the water column above the cuff. Five new ETTs of each type were tested. RESULTS: The guayule latex cuffs showed no leakage at all the PEEP levels. Both the cylindrical and conical polyurethane cuffs showed limited leakage (2.1 ± 1.8 cm of water) only for PEEP zero. The PVC cuffs showed reduced leakage with increasing PEEP: 8.4 ± 1.5, 7.8 ± 2.2, 2.2 ± 1.0, and 0 cm of water at 0, 5, 10, and 15 cmH(2)O, respectively. Among all the PVC cuffs, the conical shape ensured higher sealing properties. CONCLUSIONS: The guayule latex cuffs always prevented fluid leakage; the polyurethane and PVC cuffs required incremental levels of PEEP to prevent fluid leakage ever-present at zero PEEP.

Increase of oxygen consumption during a progressive decrease of ventilatory support is lower in patients failing the trial in comparison with those who succeed.

BACKGROUND: The aim of this study was to test the hypothesis that, during weaning from mechanical ventilation, when the pressure support level is reduced, oxygen consumption increases more in patients unable to sustain the decrease in ventilatory assistance (weaning failure). METHODS: Patients judged eligible for weaning were enrolled. Starting from 20 cm H2O, pressure support was decreased in 4-cm H2O steps, lasting 10 min each, until 0 cm H2O; this level was kept for 1 h. The average oxygen consumption from the last 3 min of each step, along with other ventilatory variables, was measured by indirect calorimetry (M-CAiOVX "metabolic module," Engstrom Carestation; GE Healthcare, Madison, WI) and recorded. Patients were defined as belonging to the failure group if, at any moment, they developed signs of respiratory distress according to standard criteria, or to the success group otherwise. RESULTS: Twenty-eight patients were studied. In most patients, the minimum oxygen consumption was not recorded at the highest pressure support applied. Sixteen patients were able to complete the weaning trial successfully, whereas 12 failed it; the success group had a minimum oxygen consumption lower than failure group (mean +/- SD: 174 +/- 44 vs. 215 +/- 53 ml/min, P < 0.05). Moreover, although respiratory drive (assessed by P0.1) increased more in the failure group, this group had a lower increase in oxygen consumption, contradicting our hypothesis. CONCLUSIONS: Patients failing a decremental pressure support trial, in comparison with those who succeed, had an higher baseline oxygen consumption and were not able to increase their oxygen consumption in response to an increased demand.