spontaneous breath
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Objective. The study focused on the nursing strategies of patients with ventilator-associated pneumonia (VAP) and multicriteria decision analysis (MCDA) in nursing supervision, so as to improve the survival rate and prognosis of patients with VAP. Methods. 200 patients of the database in the ICU who required mechanical ventilation were selected as research subjects. They were divided into control group and intervention group according to different nursing measures. The incidence of VAP was compared between the two groups, and 15 experts were consulted on the prevention measures of VAP. On the basis of ARIMA-GARCH mathematical modeling, using the method of multicriteria decision analysis, the cluster nursing strategy for ventilator-associated pneumonia patients was developed and verified. Results. In the control group, of the 34 patients infected with VAP, Gram-positive bacteria were detected in 11 cases, including 6 cases of Streptococcus pneumoniae, 3 cases of Escherichia coli, and 2 cases of golden yellow Staphylococcus. Gram-negative bacteria were detected in 10 cases, including 5 (50%) cases of Acinetobacter baumannii, 2 cases of Klebsiella pneumoniae, 2 cases of Brucella Bacillus, and 1 case of Pseudomonas aeruginosa. In the intervention group, 18 cases were diagnosed with VAP, including 4 (44.4%) cases of bacterial infection, 3 (44.4%) cases of virus infection, and 2 (22.2%) cases of fungal infection. According to the opinions of the 15 experts, a total of 6 bundled measures were adopted to prevent VAP, including 0.1% chlorhexidine for oral care; strict implementation of hand hygiene; the daily wake-up for spontaneous breath training and extubation assessment; continuous subglottic suction; raising the bed head by 30°–45°; and nasal feeding through the nasal tube without special condition. Conclusion. There are many factors that affect the occurrence of VAP in mechanically ventilated patients in the ICU, and the imperfect measures of bundles of care are the main one. The implementation rates of distinct intervention strategies are different. The implementation rate of 2 measures is lower than 95%, which are the continuous subglottic suction and daily wake-up for spontaneous breath training and extubation assessment.

Previous reports suggested the existence of direct somatic motor control over heart rate (fH) responses during diving in some marine mammals, as the result of a cognitive and/or learning process rather than being a reflexive response. This would be beneficial for O2 storage management, but would also allow ventilation-perfusion matching for selective gas exchange, where O2 and CO2 can be exchanged with minimal exchange of N2. Such a mechanism explains how air breathing marine vertebrates avoid diving related gas bubble formation during repeated dives, and how stress could interrupt this mechanism and cause excessive N2 exchange. To investigate the conditioned response, we measured the fH-response before and during static breath-holds in three bottlenose dolphins (Tursiops truncatus) when shown a visual symbol to perform either a long (LONG) or short (SHORT) breath-hold, or during a spontaneous breath-hold without a symbol (NS). The average fH (ifHstart), and the rate of change in fH (difH/dt) during the first 20 s of the breath-hold differed between breath-hold types. In addition, the minimum instantaneous fH (ifHmin), and the average instantaneous fH during the last 10 s (ifHend) also differed between breath-hold types. The difH/dt was greater, and the ifHstart, ifHmin, and ifHend were lower during a LONG as compared with either a SHORT, or an NS breath-hold (P < 0.05). Even though the NS breath-hold dives were longer in duration as compared with SHORT breath-hold dives, the difH/dt was greater and the ifHstart, ifHmin, and ifHend were lower during the latter (P < 0.05). In addition, when the dolphin determined the breath-hold duration (NS), the fH was more variable within and between individuals and trials, suggesting a conditioned capacity to adjust the fH-response. These results suggest that dolphins have the capacity to selectively alter the fH-response during diving and provide evidence for significant cardiovascular plasticity in dolphins.

Introduction and aim: Studies regarding asynchrony in patients in the cardiac postoperative period are still only a few. The main objective of our study was to compare asynchronies incidence and its index (AI) in 3 different modes of ventilation (volume-controlled ventilation [VCV], pressure-controlled ventilation [PCV] and pressure-support ventilation [PSV]) after ICU admission for postoperative care. Methods: A prospective parallel randomised trial in the setting of a non-profitable hospital in Brazil. The participants were patients scheduled for cardiac surgery. Patients were randomly allocated to VCV or PCV modes of ventilation and later both groups were transitioned to PSV mode. Results: All data were recorded for 5 minutes in each of the three different phases: T1) in assisted breath, T2) initial spontaneous breath and T3) final spontaneous breath, a marking point prior to extubation. Asynchronies were detected and counted by visual inspection method by two independent investigators. Reliability, inter-rater agreement of asynchronies, asynchronies incidence, total and specific asynchrony indexes (AIt and AIspecific) and odds of AI ≥10% weighted by total asynchrony were analysed. A total of 17 patients randomly allocated to the VCV (n= 9) or PCV (n=8) group completed the study. High inter-rated agreement for AIt (ICC 0.978; IC95%, 0,963-0.987) and good reliability (r=0.945; p<0.001) were found. Eighty-two % of patients presented asynchronies, although only 7% of their total breathing cycles were asynchronous. Early cycling and double triggering had the highest rates of asynchrony with no difference between groups. The highest odds of AI ≥10% were observed in VCV regardless the phase: OR 2.79 (1.36-5.73) in T1 vs T2, p=0.005; OR 2.61 (1.27-5.37) in T1 vs T3, p=0.009 and OR 4.99 (2.37-10.37) in T2 vs T3, p<0.001. Conclusions: There was a high incidence of breathing asynchrony in postoperative cardiac patients, especially when initially ventilated in VCV. VCV group had a higher chance of AI ≥10% and this chance remained high in the following PSV phases.

Pulse pressure variation can predict fluid responsiveness in strict applicability conditions. The purpose of this study was to describe the clinical applicability of pulse pressure variation during episodes of patient hemodynamic instability in the intensive care unit. We conducted a five-day, seven-center prospective study that included patients presenting with an unstable hemodynamic event. The six predefined inclusion criteria for pulse pressure variation applicability were as follows: mechanical ventilation, tidal volume >7 mL/kg, sinus rhythm, no spontaneous breath, heart rate/respiratory rate ratio >3.6, absence of right ventricular dysfunction, or severe valvulopathy. Seventy-three patients presented at least one unstable hemodynamic event, with a total of 163 unstable hemodynamic events. The six predefined criteria for the applicability of pulse pressure variation were completely present in only 7% of these. This data indicates that PPV should only be used alongside a strong understanding of the relevant physiology and applicability criteria. Although these exclusion criteria appear to be profound, they likely represent an absolute contraindication of use for only a minority of critical care patients.

Results of research of biomechanics of breathing at patients with progressing muscular dystrophy (PMD) and their interpretation are unique. Compared indicators of ventilating function of lungs and indicators of mechanics of breathing at 31 patients with PMD to 1–2 extent of motive frustration and 17 patients with 3–4 extent of motive frustration. In both groups of sick MVL and OFV-1 are lowered to the same extent, bronchial resistance isn’t increased. In the 2nd group the reserve volume of an expiratory is reduced for the account decrease in force of respiratory muscles is decreased. Elastic draft of lungs is reduced, the coefficient of functional activity of lungs is increased. At spontaneous breath the tensile properties of lungs are lowered, increased elastic fraction of work of breathing. The general nonelastic resistance of lungs is on the average equally increased in both groups at the expense of increase of tissue friction. At 12 sick PMD the abnormal respiratory loop came to light: completely I was absent at 8 patients and at 4 there was no inspiratory or expiratory part of a loop. Changes of indicators of mechanics of breath are the in generally functionally, and are considered as manifestation of compensatory strengthening of function of an intra pulmonary source of mechanical energy.

Vagally mediated reflexes play an important role in the generation of respiratory responses to various stimuli. This study examined the role of vagally mediated mechanisms in the generation of the respiratory responses to progressive brain hypoxia secondary to carboxyhemoglobinemia (HbCO 013;55%) in six unanesthetized goats. Ventilation, respiratory cycle timing, and the lung inflation reflex were measured before and during CO inhalation in intact and bilaterally vagotomized animals. Our results indicate that vagal reflexes contribute a small magnitude of the hyperpnea caused by carboxyhemoglobinemia. Furthermore, in contrast to that reported for CO2 inhalation, the tachypneic nature of the ventilatory response to CO is not a vagally mediated phenomenon. CO inhalation had a biphasic influence on the strength of the lung inflation reflex measured as the ratio of inspiratory time during occlusion (TIoccl) to inspiratory time of the preceding spontaneous breath (TIspont). At HbCO levels of 35%, TIoccl/TIspont was enhanced, whereas at HbCO levels of 55% of ratio fell to unity, indicating abolition of the reflex. After vagotomy, this ratio was unity at all levels of carboxyhemoglobinemia.