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Conventional gas ventilation, liquid-assisted high-frequency oscillatory ventilation, and tidal liquid ventilation in surfactant-treated preterm lambs.

This study was designed to compare the efficacy and potential protective or injurious effects of tidal liquid ventilation (TLV), liquid-assisted high-frequency oscillatory ventilation (LA-HFOV), and high PEEP conventional mechanical ventilation (CMV) in neonatal respiratory distress syndrome. Preterm lambs (124-126 days gestation), prophylactically treated with natural surfactant, were allocated to one of the treatment modalities or to an untreated fetal control group (F), euthanised after tracheal ligation. LA-HFOV animals received an intratracheal loading dose of 5 mL x kg(-1) followed by a continuous intrapulmonary instillation of 12 mL x kg(-1);h(-1) FC-75 perfluorocarbon liquid. The ventilation strategies aimed at keeping clinically appropriate arterial blood gases for a study period of 5 hours. A histological lung injury score was calculated and semiquantitative morphometry was performed on lung tissue fixed by vascular perfusion. The alveolar-arterial pressure difference for O2 was significantly lower throughout the study in TLV compared to CMV lambs; at 1, 2, and 5 hours, oxygenation was better in TLV when compared to LA-HFOV. Total lung injury scores in TLV lambs were significantly lower than in either CMV or LA-HFOV animals, but higher when compared to F. CMV and LA-HFOV induced an excess of collapsed and overdistended alveoli, whereas in TLV alveolar expansion was normally distributed around predominantly normal alveoli. CMV and LA-HFOV, but not TLV, were associated with an excess of dilated airways. Thus, in the ovine neonatal RDS model, TLV compared favourably to either gas ventilation strategy by its more uniform ventilation, reduced lung injury, and improved gas exchange.

Analysis of Variance↗

Comparison of the effects of pressure support ventilation delivered by three different ventilators during weaning from mechanical ventilation.

OBJECTIVE: To compare the effects of pressure support ventilation (PSV) delivered at the same level by three different ventilators on patients' work of breathing (WOB), breathing pattern and gas exchange. DESIGN: Prospective, self-controlled clinical study. SETTING: Intensive care unit of a tertiary university hospital. PATIENTS: Nine intubated adult patients during weaning from mechanical ventilation. INTERVENTIONS: Patients were randomly connected to one of three ventilators: the Siemens Servo 900 C (SC), the Ohmeda CPU 1 (CPU), and the Engström Erica (EE) during both zero cmH2O PSV and 15 cmH2O PSV. MEASUREMENTS AND RESULTS: During zero PSV, there was no significant difference in terms of WOB, VT, VE, or auto-PEEP among the three ventilators, although there was a trend towards higher levels of WOB with EE. During 15 cmH2O PSV, WOB was significantly less with SC than with EE or CPU (0.47 +/- 0.48 J/l for SC, 1.0 +/- 0.48 for EE and 0.78 +/- 0.51 for CPU1, p = 0.003). WOB was 64% less than at zero PSV with SC but only 38% less with EE. This was associated with a different pressurization shape, as assessed by the interior surface of Paw-VT loops (1.23 +/- 0.09 J/l for SC, 0.9 +/- 0.02 for EE, and 0.79 +/- 0.18 for CPU; p < 0.001). At 15 cmH2O PSV, auto-PEEP was significantly lower with SC than with EE (1.7 +/- 2.1 cmH2O for SC, 4.7 +/- 3.6 for EE, and 2.8 +/- 0.3 for CPU; p = 0.04). External expiratory resistances, in cmH2O/l/s, were significantly higher with EE than with CPU or SC (12.9 +/- 3.2 EE, 7.5 +/- 2.4 CPU, 5.9 +/- 0.5 SC; p < 0.001). CONCLUSION: During PSV, the different working principles of different mechanical ventilators profoundly affect patient's WOB. Among the various factors, velocity of pressurization of PSV may play a role in its efficacy in unloading the respiratory muscles.

Acute Disease↗

Diaphragmatic movement studied with ultrasound during spontaneous breathing and mechanical ventilation with intermittent positive pressure ventilation (IPPV) and airway pressure release ventilation (APRV) in man.

Earlier knowledge about diaphragmatic movement during mechanical ventilation is based on radiological information. Since real-time bed-side monitoring is now possible the movement of the right hemidiaphragm was studied using ultrasound (US), both during spontaneous and mechanical ventilation. Nine healthy non-medicated volunteers lying supine were exposed to the following ventilation modes in random order: 1. breathing air at ambient pressure, or 2. at 7.6 mmHg of CPAP or 3. mechanical ventilation with airway pressure release ventilation (APRV), or 4. with IPPV, by mask. The movement of the diaphragm was recorded with a US sector transducer, imaging the ventral, dome and dorsal parts. The maximal movement was detected in the dome in four volunteers during spontaneous breathing with both ambient pressure and CPAP, but in the ventral part in seven and six volunteers, respectively, during APRV and IPPV. Diaphragmatic movement can be studied with US and the findings support the earlier study, with the diaphragm shifting towards the non-dependent regions of the lungs during mechanical ventilation. In this respect APRV is similar to IPPV.

Adult↗

New modes of mechanical ventilation: proportional assist ventilation, neurally adjusted ventilatory assist, and fractal ventilation.

Increased knowledge of the mechanisms that determine respiratory failure has led to the development of new technologies aimed at improving ventilatory treatment. Proportional assist ventilation and neurally adjusted ventilatory assist have been designed with the goal of improving patient-ventilator interaction by matching the ventilator support with the neural output of the respiratory centers. With proportional assist ventilation, the support is continuously readjusted in proportion to the predicted inspiratory effort. Neurally adjusted ventilatory assist is an experimental mode in which the assistance is delivered in proportion to the electrical activity of the diaphragm, assessed by means of an esophageal electrode. Biologically variable (or fractal) ventilation is a new, volume-targeted, controlled ventilation mode aimed at improving oxygenation; it incorporates the breath-to-breath variability that characterizes a natural breathing pattern.

Algorithms↗

High-frequency oscillatory ventilation, partial liquid ventilation, or conventional mechanical ventilation in newborn piglets with saline lavage-induced acute lung injury. A comparison of gas-exchange efficacy and lung histomorphology.

It has been reported that, in diseased lungs, either partial liquid ventilation (PLV) or high-frequency oscillatory ventilation (HFOV) can improve oxygenation better and with less lung injury than conventional mechanical ventilation (CMV). This study was intended as a preclinical comparison between the effects of HFOV, PLV and CMV on gas exchange, lung mechanics and histology. Fifteen anesthetized newborn piglets, with respiratory insufficiency due to repeated saline lung lavage, were allocated to either a PLV, HFOV or CMV (n = 5 each) strategy, and treated for 4 h. Within 30 min of commencing therapy, PLV, HFOV, and CMV improved arterial PO2 (Pa,O2), alveoloarterial oxygen gradient (P(A-a),O2), oxygenation index (OI), venous admixture (va), and arterial PCO2 (Pa,CO2). After 4 h, oxygenation parameters (Pa,O2, P(A-a),O2, OI and venous admixture) were significantly better in the HFOV group than in the PLV group; the CMV group showed a higher Pa,O2 and lower OI than the PLV group. Gas exchange at the end of the experiment was not different from baseline in the HFOV and CMV groups. Lung histology and morphometry were performed after perfusion-fixation at endotracheal deflation pressure corresponding to mean airway pressure at the end of the experiment. Lung injury score and mean linear intercept were not different between the three treatment groups. We conclude that in this model, gas exchange improved significantly in all three ventilation strategies. Indices of oxygenation improved less during PLV. The saline lavage-induced acute lung injury model used as in this study, is less stable than previously thought. The final lung injury is not influenced by the ventilation strategy. We speculate that the impaired gas exchange during PLV is an expression of diffusion limitation and ventilation-perfusion mismatch in a recovering lung.

Animals↗

Partial liquid ventilation ventilates better than gas ventilation.

Partial liquid ventilation (PLV) improves oxygenation in several models of lung injury. However, PLV has only been compared with conventional gas ventilation (GV) with low PEEP. Both PLV and GV can markedly improve oxygenation when PEEP is set above the lower corner pressure (Plc) on the inspiratory pressure-volume (P-V) curve of the total respiratory system. We questioned if the use of PEEP set above the Plc during PLV and GV would result in similar gas exchange. Lung injury was induced in 12 sheep by saline lavage before randomization to PLV (n = 6) or GV (n = 6). Animals in the PLV group were filled with perflubron (22 ml/kg) until a meniscus at the teeth was observed. Both groups were then ventilated with pressure control (FI(O(2)), 1.0; rate, 20/min; I:E, 1:1) and PEEP (1 cm H(2)O above the Plc on the inspiratory P-V curve). Peak inspiratory pressure (PIP) was limited to 35 cm H(2)O. Animals were ventilated for 5 h and then killed for histologic examinations. All 12 animals survived the 5-h ventilation period. After increasing PEEP above Plc, Pa(O(2)) increased significantly (p < 0.01) in both the GV and the PLV groups, but it did not differ significantly between groups (p = 0.86) at any time during the experiment. Pa(CO(2)) and VD/VT in GV increased markedly throughout the experiment after increasing PEEP (p < 0.001), but there was no significant change in Pa(CO(2)) in PLV (p = 0.13). Mean arterial blood pressure, mean pulmonary artery pressure, pulmonary artery occlusion pressure, and central venous pressure, increased and SVR decreased in GV (p < 0.05). The extent and the severity of lung injury in the dependent regions was greater in the GV group (p < 0.05). Both PLV and GV improved oxygenation, but PLV resulted in better ventilation than GV while preserving lung structure when PEEP was set 1 cm H(2)O above the Plc and PIP limited to 35 cm H(2)O.

Animals↗

A comparison of continuous positive pressure ventilation, combined high frequency ventilation and airway pressure release ventilation on experimental lung injury.

In pigs with oleic induced lung injury, the effectiveness of combined high frequency ventilation (CHFV, with VDR-Phasitron) and airway pressure release ventilation (APRV) were compared to continuous positive pressure ventilation (CPPV) in a randomized study. The respiratory rate was 15/min, CPAP 8 mmHg and FiO2 0.25. PaCO2 was maintained at 5 kPa. PaO2 was significantly lower with APRV (12.5 +/- 3.9 kPa, CPPV: 15.8 +/- 3.9 kPa, and CHFV: 15.5 +/- 3.2 kPa). This was in accordance with the lowest peak airway pressure during APRV (20.9 +/- 4.8 mmHg, CPPV: 26.3 +/- 4.4 mmHg and CHFV: 28.2 +/- 3.7 mmHg). There was no difference in the pericardiac pressure between the 3 ventilation modes. The pressure related depressive effects on the cardiovascular function during CHFV and APRV were similar to those during CPPV. Adequate oxygenation and ventilation could be achieved with both CHFV and APRV, but these methods were not superior to CPPV.

Animals↗

Speed of collapse of the non-ventilated lung during single-lung ventilation for thoracoscopic surgery: the effect of transient increases in pleural pressure on the venting of gas from the non-ventilated lung.

A study of 10 anaesthetised patients placed in the lateral position for thoracoscopic surgery assessed whether transient increases in pleural pressure on the side of the non-ventilated lung might increase the speed at which gas vents from that lung. The transient increases in pleural pressure were generated by the mediastinal displacement that occurs with each inspiratory phase of positive pressure ventilation of the dependent lung. When combined with a unidirectional valve allowing gas to flow out of the non-ventilated lung, and a second valve allowing ambient airflow into, but not out of, the thoracic cavity via an initial thoracoscopy access site, this mediastinal displacement could conceivably serve to 'pump' gas out of the non-ventilated lung. Using the four different combinations of valve inclusion or omission, the volume of gas that vented from the non-ventilated lung into a measuring spirometer was recorded during a 120-s measurement sequence. It was found that the speed of venting was not increased by the transient increases in pleural pressure, and that in all but one of a total of 34 measurement sequences, venting had ceased by the end of the sequence. Gas venting was a mean (SD) of 85.5 (11.9)% complete in 25 s (five breaths), and 96.6 (6.1)% complete in 60 s. This prompt partial lung collapse very likely reflected the passive elastic recoil of the lung, while the failure of transient increases in pleural pressure to result in ongoing venting of gas was probably a consequence of airways closure as the lung collapsed. It is concluded that techniques that aim to speed lung collapse by increasing pleural pressure are unlikely to be effective.

Adolescent↗

A new infant ventilator for normal and high-frequency ventilation: influence of tracheal tube on distal airway pressure during high-frequency ventilation.

A new infant ventilator for both normal and high-frequency ventilation is described. High pressure gas delivered via a jet in the breathing limb of a T-piece, in which there are no valves, drives respiratory fresh gas (RFG), supplied to the tracheal tube from any low pressure source, into the lungs. Observations on anesthetized rabbits showed that after setting up for a PaCO2 of 36 torr at 30 cycle/min, it remained around 36 torr when the ventilation frequency was progressively increased to 200 cycle/min. The mean peak proximal airway and tracheal pressures were 13 and 12, 11 and 7, and 13 cm H2O (PEEP 2.1 cm H2O) and 7.4 cm H2O (PEEP 3.1 cm H2O) at 30, 100 and 200 cycle/min, respectively. In this open valveless breathing system, desynchronized spontaneous and artificial ventilation occurred quietly without any marked variation in the airway pressures. This preliminary study on a new pneumatic system shows its potential for simplifying and improving infant ventilation.

Animals↗

[Mechanical ventilation in pediatrics (III). Weaning, complications and other types of ventilation. Weaning from mechanical ventilation].

Weaning from mechanical ventilation can be defined as the process that allows the transition from mechanical ventilation to spontaneous breathing. This process can account for a significant proportion of total ventilation time and failure to resume spontaneous breathing affects patient outcome. Thus, to ensure maximum success, patient readiness for weaning and extubation should be evaluated through the following steps: the patient must fulfill pre-established clinical and ventilatory support criteria for extubation, the patient should be observed during a breathing trial on minimal or no ventilatory support, and variables used to predict weaning success should indicate a favorable outcome. Breathing trials are usually conducted while the patient breathes spontaneously through a T-tube system or through the ventilator circuit on minimal ventilatory support. Neither of these methods has proved superior to the other. The best prognostic indicator of weaning outcome is clinical assessment of respiratory effort. Once mechanical ventilation is discontinued, it may be necessary to treat post-extubation complications or even to resume ventilatory support.

Humans↗

[Mechanical ventilation in pediatrics (III). Weaning, complications and other types of ventilation. Noninvasive ventilation].

Noninvasive ventilation (NIV), i.e. without tracheal intubation, has been reintroduced for the treatment of respiratory failure to reduce the complications of mechanical ventilation. Nowadays, NIV with positive pressure is the preferred method, applied through a mask held in place by a harness. Several masks can be used (nasal, bucconasal facial) and a variety of means can be used to keep them in place. Many respirators can be selected, ranging from those traditionally used in the intensive care unit(ICU) to specific NV respirators and conventional ICU respirators with specific software for NIV. Many respiratory modalities can be used according to the respirator (biphasic positive airway pressure [BIPAP], proportional assist ventilation, pressure support, synchronized intermittent mandatory ventilation [SIMV], etc.). NIV is mainly indicated in exacerbations of chronic respiratory failure: neuromuscular diseases, pretransplantation cystic fibrosis, and obstructive sleep apnea syndrome. It is also indicated in acute respiratory failure: pneumonia, status asthmaticus, and acute lung edema. The main contraindications are a weakened airway protection reflex(absent cough reflex) and hemodynamic instabiity. The advantages of NIV derive mainly from avoiding the complications associated with invasive ventilation. NIV also presents some disadvantages, especially the greater workload involved to ensure good patient adaptation to the respirator. The most common sequelae of NIV are skin lesions due to pressure on the nasal bridge.

Acute Disease↗

Ventilation at high respiratory frequencies. High frequency positive pressure ventilation, high frequency jet ventilation and high frequency oscillation.

This paper reviews the development of different methods of ventilation at respiratory rates higher than 60 per minute (1 Hz) along with data on experimental and clinical uses of the techniques. The definitions and terms that have been used for these high rates at the present time are confusing. An attempt to clarify the terms has been made. Whereas high frequency positive pressure ventilation (HFPPV) refers to respiratory rates between 60-110 per minute (1-1.8 Hz), high frequency jet ventilation (HFJV) usually refers to rates between 110-400 per minute (1.8-6.7 Hz) and high frequency oscillation (HFO) refers to rates above 400 and up to 2400 per minute (40 Hz). It should be recognised that this differentiation in terminology is rather arbitrary and does not necessarily represent a sudden switch to different physiological methods of ventilation. In view of the various techniques which are involved in ventilation methods utilising rates greater than 60 per minute (1 Hz), it is the purpose of the present work to review the literature. In so doing, the contrasting rates, mechanical equipment, and experimental and clinical uses of these different methods will be discussed in order to clarify their potential contribution to clinical medicine.

Animals↗

Experimental studies on artificial ventilation using a tidal volume ventilator. Mechanics and dynamics of ventilation.

In 24 piglets (2.7-24.5 kg b.w.), the mechanics of ventilation, the accuracy of dosage of respiratory volumes, and the influence of the ventilator's volume/pressure characteristics (Cvent, "internal compliance") on the dynamic course of insufflation were studied. A linear relationship was shown to exist between tidal volume and end-inspiratory tracheal pressure and between tidal volume and insufflation time. The insufflation time was reduced to about 50% of previously registered values. The error between set and registered tidal volume was found to be 6.0 +/- 2.7%. During the insufflation a linear relationship was found between the instant amount of delivered breathing gas and the corresponding endotracheal pressure change. The ventilator's Cvent did (and body size, total compliance and tidal volume did not) significantly influence the size of the direction coefficient for the linear instantaneous volume/pressure relationship, the magnitude of tracheal peak pressure and a short insufflation time, and vice versa. The use of greater power from the ventilator resulted in a significant shortening of the duration of insufflation and vice versa. The duration of insufflation is the parameter of choice in evaluating the efficiency of the ventilatory equipment. When the ventilator's performance is defined, measurements of the duration of insufflation may enable evaluation of conditions within the lungs.

Animals↗

Synchronized intermittent mandatory ventilation with and without pressure support ventilation in weaning patients with COPD from mechanical ventilation.

This prospective study compared two weaning modalities in COPD patients requiring mechanical ventilation (MV) for acute respiratory failure. Nineteen patients with COPD were studied when their precipitating illness was controlled. Although they satisfied the conventional bedside weaning criteria, they could not tolerate any reduction in the respirator rate below 10 cycles/min. At this time, patients were randomized into two groups receiving either synchronized intermittent mandatory ventilation (SIMV) with pressure support ventilation (PSV) (group 1) or SIMV alone (group 2). The volumetric support of ventilation (SIMV rate) was progressively decreased in both groups according to the patient's tolerance with a concurrent decrease in the barometric support of ventilation (PSV levels from 15 cm H2O to 6 cm H2O). At each step of SIMV rate, we found no difference between group 1 and group 2 in arterial blood gases, blood pressure, heart rate, airway occlusion pressure, maximal inspiratory pressure, and oxygen cost of breathing (OCB). At each step, however, group 1 patients showed significantly higher spontaneous tidal volume and lower spontaneous breathing frequency than did group 2 patients. We found a slight but not significant tendency to a shorter weaning period with than without PSV, but no difference in the weaning success. We concluded that (1) conventional weaning criteria might be inaccurate in COPD patients, (2) SIMV appeared very useful in weaning COPD patients from MV, (3) PSV marginally reduced the weaning period when added to SIMV, and (4) the OCB was not significantly improved with PSV.

Aged↗

[Intraoperative dual-mode independent lung ventilation for open-chest surgery: conventional volume-set ventilation in healthy lung and high frequency jet ventilation in diseased lung].

An effort by the anesthesiologist to maintain adequate ventilation during thoracic surgery is sometimes disturbing for the operative procedures of the surgeon. Unilateral ventilation with a large tidal volume, leaving the operative site unventilated, may provide an adequate and quiet operative field, but is opposed by the problem of disturbance in pulmonary gas exchange. The application of high frequency jet ventilation has recently been introduced to solve these problems. However, the disadvantage inherent to this technique is the tendency to produce carbon dioxide retention although it provides adequate oxygenation. In the present study, using a double lumen endobronchial tube, the large-tidal volume ventilation of the non-operative site and the high frequency jet ventilation with small tidal volume of the operative site were performed simultaneously. This technique provided the satisfactory condition of operative field, i.e., "quiet lung". Also, the serial gas analysis of the arterial and mixed venous blood samples indicated the satisfactory condition of pulmonary gas exchange.

Aged↗

A comparison of two-lung high frequency positive pressure ventilation and one-lung ventilation plus 5 cm H2O non-ventilated lung CPAP, in patients undergoing anaesthesia for oesophagectomy.

A randomised prospective controlled study was conducted during a one-year period on patients scheduled for oesophagectomy via a right thoracotomy approach. Twenty-two patients received one-lung ventilation (OLV group) and twenty patients received high frequency positive pressure ventilation (HFPPV group). Episodic hypoxaemia (SaO2 less than 90% for greater than 30 seconds, FiO2 1.0) occurred in eleven patients in the OLV group and six patients in the HFPPV group. No patient in the HFPPV group had a severe desaturation episode (SaO2 less than 80%, FiO2 1.0) compared with nine patients in the OLV group (P less than 0.05). The mean peak inspiratory pressure and average mean airway pressure were significantly lower in the HFPPV group 28.8 (SD 7.7) and 7.2 (SD 2.4) cm H2O respectively, compared with the OLV group, 40.0 (SD 9.9) and 11.9 (SD 4.9) cm H2O (P less than 0.05). Two-lung high frequency positive pressure ventilation has some advantages over one-lung ventilation during the thoracotomy phase of oesophagectomy because it is easy to administer, does not significantly compromise the surgical exposure and is associated with fewer severe undesirable physiological disturbances.

Aged↗

Rescue from pediatric ECMO with prolonged hybrid intratracheal pulmonary ventilation. A technique for reducing dead space ventilation and preventing ventilator induced lung injury.

Hybrid intratracheal pulmonary ventilation (h-ITPV) is a continuous flow ventilatory technique that uses a "reverse thruster" catheter to redirect the flow of gas away from the carina. We report here the use of h-ITPV in a pediatric patient with acute sickle cell chest syndrome who required venoarterial ECMO support because of refractory hypoxemic respiratory failure. Her ECMO course was complicated by air leaks, coagulopathy, cardiac tamponade, and necrotizing tracheobronchitis. She could be weaned from ECMO only by maintaining high pressure conventional ventilatory support. To prevent ventilator induced barotrauma, we initiated h-ITPV and weaned her from ECMO bypass. After 12 days of h-ITPV, with tidal volumes of 2-3 ml/kg at carinal peak inspiratory pressures of 25-30 cm H2O, the air leaks ceased and h-ITPV was discontinued. Dead space ventilation fraction (VD/VT) as low as 0.29 was achieved with this technique. Post-h-ITPV bronchoscopy displayed a dramatic resolution of the necrotizing tracheobronchitis. The patient survived and was discharged from the hospital. We conclude that the use of hybrid ITPV may facilitate weaning from ECMO to low pressure conventional ventilation and prevent the development of pulmonary barotrauma.

Acid-Base Equilibrium↗

Comparison of bag-valve-mask, manually triggered ventilator, and automated ventilator devices used while ventilating a nonintubated mannikin model.

OBJECTIVE: To determine whether there were differences in tidal volume (Vt), minute volume (MV), average mask leak per breath (ML), gastric insufflation (GI), and peak airway pressure (PAP) when ventilating a nonintubated mannikin with a bag-valve-mask (BV), manually triggered ventilator (MTV), and automated ventilator (AV). The authors' hypothesis was that there would be no differences among the devices for any of these variables. METHODS: This was a prospective in-vitro experimental model. A convenience sample of 19 emergency medical technicians (EMTs) ventilated a nonintubated mannikin-mechanical test lung model with the BV, MTV (flow rate 40 L/min; pressure relief 55 cm H2O), and AV (800 mL/breath; rate 12). Each subject, blinded to volume and pressure gauges, used each device for 2 minutes at both normal (0.1 cm H2O) and poor (0.04 cm H2O) compliances. Vt, MV, GI, and PAP were measured directly and ML was calculated. A survey was issued to the EMTs who participated in the study. Data were analyzed with repeated-measures ANOVA and the Bonferroni-Dunn multiple comparison test with alpha set at 0.05. RESULTS: At the normal compliance, PAP was higher for the BV than the MTV (p = 0.0001) and AV (p < 0.0001). MV was also greater with the BV than with the AV (p = 0.001). PAP was also higher at the poor compliance with the BV than with the MTV and AV (p = 0.008 and 0.013, respectively). The BV had a higher GI at this compliance (p < 0.0001) and a higher ML than the AV (p = 0.002). CONCLUSION: All three devices delivered similar volumes when used by EMTs, but the BV was associated with higher PAP, ML, and GI.

Adult↗