Case report: fatal pneumonia caused by new sequence type Legionella pneumophilia serogroup 1.

INTRODUCTION: Legionnaires' disease is caused by Legionella bacteria, and commonly manifests as pneumonia and has a high fatality rate. PATIENT CONCERNS: This case study reports on the fatal incident of a patient, initially diagnosed with pneumonia, and subsequently diagnosed with Legionnaires' disease caused by a new sequence type (ST) of Legionella. DIAGNOSIS: It is speculated that the patient acquired Legionnaires' disease from a contaminated water source. Legionnaires' disease was diagnosed using the Legionella urinary antigen assay and bacterial cultures of respiratory secretions; Legionella pneumophilia Type 1 was also identified through serological testing. Sequence-based typing of the cultured bacterium revealed it to be a previously unidentified species, and it was named ST2345 new-type. INTERVENTIONS: In addition to the treatment of Legionnaires' disease, blood samples taken on the second day of admission showed a co-infection of Candida tropicalis, which was treated with anti-fungal treatment. The patient improved after a week, however, on the seventh day of administration lower respiratory secretions showed the growth of Klebsiella pneumonia, indicative of ventilator-associated pneumonia. OUTCOMES: Despite active treatment, the patient passed away due to multiple organ failure. As this was a fatal case, further research is needed to determine whether the critical condition of this case was related to the virulence of the novel Legionella strain. CONCLUSION: A key finding of this study is that treatment for suspected Legionnaires' disease must be administered rapidly, as infection with Legionella may give rise to secondary pathogenic infections.

Association between Chlamydia pneumoniae infection and lung cancer: a meta-analysis.

BACKGROUND: The aim of this study is to explore the correlation between Chlamydia pneumoniae (C. pneumoniae) infection and lung carcinoma. METHODS: Databases of PubMed, Embase, Embase, Ovid, Wanfang and China National Knowledge Infrastructure (CNKI) database were investigated for eligible literatures from their establishments to February, 2019. Included studies were selected according to specific eligibility criteria. Statistical analysis was performed by RevMan 5.3 software. RESULTS: Thirteen studies with 2,553 lung carcinoma cases and 2,460 controls were eligible for meta-analysis. The pooled results indicated that the C. pneumoniae infection IgA significantly increased the risk of lung carcinoma (OR =3.19; 95% CI, 1.96-5.19; P<0.00001) by random effect model. And for serum IgG, the pooled OR was 2.02 (95% CI, 1.29-3.16; P<0.00001) by using the random effects model. The results indicated that the IgA positive rate was significantly higher in lung cancer patients than healthy controls. CONCLUSIONS: This meta-analysis revealed that C. pneumoniae infection may be a potential risk factor for lung carcinoma. However, due to its significant heterogeneity in the included studies, the consequence should be understood with caution.

Brief communication: detection of clinical Klebsiella pneumoniae isolates from China containing transferable quinolone resistance determinants exhibiting resistance to both aminoglycoside and ß-lactams.

Though aminoglycosides are routinely used clinically as antimicrobial agents for the treatment of severe infections due to Klebsiella pneumoniae, resistance to the same is an increasing problem. One such resistance mechanism is the production of 16S rRNA methylases. The objective of the current study was to investigate the prevalence and molecular epidemology of 16S rRNA methylase genes among 43 K. pneumoniae isolates (each of which had at least one PQMR gene and ciprofloxacin minimum inhibitory concentration greater than 0.25) recovered from nine tertiary hospitals in China. Our results suggest great genetic variation in terms of 16S rRNA methylase gene of K. pneumoniae hosts containing at least one PQMR gene. This further reinforces the clinical and systemic urgency required to characterize and block their transmission routes.

[Clinical study of mechanical ventilation in acute cardiogenic pulmonary edema patients].

OBJECTIVE: To study the application of mechanical ventilation in acute cardiogenic pulmonary edema (ACPE), and compare the changes in hemodynamics between continuous positive airway pressure proportional pressure support (CPAP-PPS) with continuous positive airway pressure-pressure support ventilation (CPAP-PSV). METHODS: Non-invasive and invasive ventilation were performed in 77 ACPE patients. At the initiation of invasive ventilation and the phase of low assist ventilation in 61 patients who were treated with mechanical ventilation longer than 24 hours, hemodynamics was monitored by partial CO(2) rebreathing method (non-invasive cardiac output, NICO) cardiopulmonary management system, and then compared the changes in the two kinds of ventilation under medicinal intervention. RESULTS: Among 33 of 61 ACPE patients underwent non-invasive ventilation, 24 were successful, and the ratio was 72.7%. Among 33 patients with invasive ventilation (including 5 in whom ventilation was switched to non-invasive mode), 11 failed. Biphasic positive airway pressure/pressure support ventilation (BIPAP/PSV) was used in pressure controlled ventilation, with high pressure (Phigh) 16-24 cm H(2)O (1 cm H(2)O=0.098 kPa), time of high pressure (Thigh) 1.5 seconds, positive end expiratory pressure (PEEP) 6-15 cm H(2)O, fractional concentration of inspired oxygen (FiO(2)) 0.5, cardiac output (CO)/cardiac index (CI) was significantly improved compared with those of initial ventilation in successful ones in invasive group, and the improvement was more significant in PPS compared with PSV in low assist ventilation (all P<0.001). Those in whom invasive ventilation was failed had a low CI (<1.5 L.min(-1).m(-2)) even under drug intervention. CONCLUSION: Hemodynamic monitoring should be performed when medicinal intervention and non-invasive/invasive ventilation are given to ACPE patients. Pressure controlled ventilation is recommended, and PEEP should be individualized (normally 6-15 cm H(2)O). Spontaneous ventilation should be restored as soon as possible, CPAP-PPS mode is practicable in patients in whom weaning of mechanical ventilation is difficult.

[Study of continuous hemodynamics monitoring techniques in patients with mechanical ventilation].

OBJECTIVE: To elucidate the relativity among three kinds of continuous hemodynamics monitoring techniques: thermodilution via Swan-Ganz catheter, pulse contour analysis method (PiCCO), partial CO(2) rebreathing method (non invasive cardiac output, NICO), in patients with mechanical ventilation. METHODS: In 13 patients with respiratory failure due to different causes, hemodynamics were continuously monitored with Swan-Ganz catheterization, PiCCO, NICO simultaneously. The therapeutic measures and the type of ventilator were similar. Data were collected at the same time points to compare the relativity among these three kinds of monitor. RESULTS: Linear relative analysis showed a good relativity in PiCCO/Swan-Ganz (r=0.883), NICO/Swan-Ganz (r=0.853) and PiCCO/NICO (r=0.857) in cardiac index (CI). CONCLUSION: PiCCO and NICO can be used as reliable measure to monitor ventilated patients bedside in intensive care unit (ICU), thus offering an assistance to optimize therapeutic strategy.

[Effect on hemodynamics during different modes of low assist ventilation].

OBJECTIVE: To observe the effect on mechanical ventilation with biphasic positive airway pressure (BIPAP), pressure support ventilation (PSV) and proportional pressure support (PPS) modes on hemodynamics in patients with either normal cardiac function or impaired cardiac function in order to optimize the time to wean mechanical ventilation in patients with severe cardiac dysfunction. METHODS: Non-invasive cardiac output (NICO) monitoring was instituted in patients 32 with respiratory failure due to different causes, when spontaneous respiration was restored, and they were separated into two groups depending on whether the cardiac index (CI) was normal (CI> or =2.0 L.min(-1).m(-2)) or not (CI<2.0 L.min(-1).m(-2)). The effects of BIPAP, PSV and PPS modes on changes in hemodynamics were compared between two groups. RESULTS: (1) In patients with normal cardiac function, CO, CI, stroke volume (SV), pulmonary capillary blood flow (PCBF) were significant higher in PSV and PPS modes than BIPAP mode, and they were highest with PPS mode, but no significant difference compared with PSV. Surround vascular resistance (SVR) was reduced significantly in PPS mode compared with BIPAP, but no significant difference was found compared with PSV. (2) In patients with cardiac dysfunction, CO, CI increased gradually when ventilated in BIPAP, PSV, PPS modes and significant difference was found among three groups. In PPS mode, CO and CI were highest. (3) The trends of peak airway pressure (Ppeak) and mean airway pressure (Pmean) were degressive in three groups. In both normal cardiac function group and cardiac dysfunction group, significant difference was found in PSV and PPS modes compared with BIPAP. Ppeak was lowest in PPS mode in cardiac dysfunction group, and there was significant difference compared with the other groups. (4) The ventilated time was significant reduced in PPS mode compared with PSV. (5) In normal cardiac function group, instinct positive end expiratory pressure (PEEPi) showed degressive trend among three different modes, and it was lowest in PPS mode, with significant difference compared with the other two groups. CONCLUSION: In PPS mode, the effect to hemodynamics in patients with severe cardiac dysfunction is minimal, so it is suitable as a weaning mode in this groups of patients.

[Clinical study of the setting of positive end expiratory pressure in patients with acute cardiogenic pulmonary edema during mechanical ventilation].

OBJECTIVE: To compare the effects on hemodynamics and lung mechanics when different positive end expiratory pressure (PEEP) levels were used in acute cardiac pulmonary edema. METHODS: Thirty-nine patients with respiratory failure and treated with mechanical ventilation were divided into two groups according to cardiac index (CI). The changes of hemodynamics [including cardiac output (CO), CI, pulmonary capillary blood flow (PCBF), central venous pressure (CVP), surround vascular resistance (SVR)], lung mechanical variables [intrinsic positive end expiratory pressure (PEEPi), peak inspiratory pressure (Ppeak), mean of airway pressure (Pmean), minute volume (MV), alveolar tidal volume (Vtalv)], percutaneous saturation of oxygen (SpO(2)) and blood pressure (BP) were determined with when selected different PEEP levels under the bi-level positive airway pressure (BIPAP) mode in normal cardiac function group (n=18, CI> or =2.0 L.min(-1).m(-2)) and poor cardiac function group (n=20, CI<2.0 L.min(-1)xm(-2)). RESULTS: In normal cardiac function group, PEEP has no effect on hemodynamics when varied from 0-13 cm H(2)O (1 cm H(2)O=0.098 kPa), and Ppeak and PEEPi increased with the elevation of PEEP. Resistance of airway (R) fell when PEEP was increased. However, in poor cardiac function group SVR, CO, CI showed curvilinear changes with an increase in PEEP, and CO, CI were high when PEEP changed from 0 to 7 cm H(2)O, but dropped markedly when PEEP was increased in 13 cm H(2)O, while the changes of SVR was the reverse of CO and CI. The effects on lung mechanics varied relatively smaller range when PEEP was set between 5-7 cm H(2)O, and the burden of breathing was slight. CONCLUSION: The mode of artificial ventilation should be adjusted according to the changes in hemodynamics and lung mechanics. PEEP should be individualized, and 5-7 cm H(2)O (normally below 10 cm H(2)O) is suitable.

[Establishment of a mathematical model of static pressure-volume curve in acute respiratory distress syndrome].

OBJECTIVE: To explore the use of second derivate in seeking the inflection points of pressure-volume (P-V) curves and compare it with the step-by-step regression method. METHODS: Under general anesthesia, tracheotomy was done in 6 adult sheep, warm physiological saline was used to lavage the respiratory, followed by alveolar lavaged via tract through bronchofiberscope to reproduce acute respiratory distress syndrome (ARDS). The low flow technique was used to trace the P-V curves before and after the saline lavage, and features of the curves were analyzed with the software of Findgraph. RESULTS: The above two methods fit the P-V data well with good accuracy both in inflation and deflation limbs in normal and ARDS animals. From the graph of second derivate, the characteristic points of the P-V curves could be exactly obtained, and the low inflection points obtained by this method were well correlated with lower inflection point (LIP) +2 cm H(2)O (1 cm H(2)O=0.098 kPa) obtained by step-by-step regression method. CONCLUSION: The graph of second derivate gained from P-V curves is useful to describe the inflection points, so that it can be helpful in instructing in setting the required parameters of the ventilator in the treatment of ARDS.

[Effects of different levels of positive end expiratory pressure on lung recruitment and hemodynamics after sustained inflation in acute respiratory distress syndrome in sheep].

OBJECTIVE: To study the effects of different levels of positive end expiratory pressure (PEEP) on recruitment and hemodynamics after sustained inflation in acute respiratory distress syndrome (ARDS) in sheep. METHODS: Twelve adult sheep were anaesthetized and ARDS was induced by lung lavage with warm normal saline. Pressure-volume (P-V) curves were traced using the low flow technique and the upper inflection point (UIP) was determined. Sustained inflation was exercised at the pressure of 5 cm H(2)O (1 cm H(2)O=0.098 kPa) below UIP, and the sheep were divided into groups according to different PEEP levels (PEEP5, PEEP10, PEEP15, PEEP20). Hemodynamics and lung mechanics values were recorded during the 2 hours of recruitment, and biopsy was performed at the end of the trial. RESULTS: There was no effect on hemodynamics and recruitment in 2 hours in PEEP5 and PEEP10 groups, but oxygenation was found to be decreased in PEEP5 group, and focal alveolar collapse was found in pathological examination. When the PEEP level reached 15 cm H(2)O, there was significant elevation in central venous pressure (CVP), and cardiac index (CI) fell remarkably, but oxygenation index and lung mechanics were improved and stable in 2 hours. CONCLUSION: Our study demonstrates that it can obviously improve oxygenation when PEEP is set at 10-20 cm H(2)O, oxygenation can be obviously improved, with little disturbance to hemodynamics in case cardiac function is normal.

[Experimental study of the safety of sustained inflation strategy in acute respiratory distress syndrome in sheep].

OBJECTIVE: To evaluate the effects of lung recruitment maneuver (RM) on hemodynamics and lung structure with sustained inflation (SI) in acute respiratory distress syndrome (ARDS) in sheep, to look for a safe range of pressure and time of SI. METHODS: Fourteen anaesthetized sheep were subjected to lung lavage through a broncho-fibroscope to reproduce ARDS, and quasi-static pressure-volume (P-V) curves were obtained with low flow technique. The upper inflection point (UIP) and the lower inflection point (LIP) were found, and then 5 cm H(2)O (1 cm H(2)O=0.098 kPa) below UIP, UIP, 10 cm H(2)O above UIP, 20 cm H(2)O above UIP as the peak pressure of SI were selected as the test pressure. They were randomized to four groups (U-5, U+0, U+10, U+20). The duration of SI was 60 seconds. Hemodynamics and oxygenation indexes were monitored and recorded during and after SI until the study was terminated 2 hours later, then CT and lung tissue biopsy were performed. RESULTS: Pneumothorax was found in U+20 groups, resulting in the death of sheep. Hemodynamics was affected significantly in other groups during SI. In U+10 groups, cardiac output (CO) and cardiac index (CI) were lowered at 15 seconds after RM began, and recovered slowly after RM; in U+0 group and U-5 group, the entire RM could be carried out to the end, and biopsy showed bullous emphysema in U+0 group. CONCLUSION: The impairment of the hemodynamics and damage to the lung structure should be prevented when RM is performed in ARDS patients, and the inflation pressure should be limited within the range of UIP or 5 cm H(2)O under UIP to avoid adverse effect on hemodynamics.

[Clinical comparative study of airway pressure release ventilation and continuous positive airway pressure ventilation].

OBJECTIVE: To evaluate the effects of airway pressure release ventilation (APRV) and continuous positive airway pressure (CPAP) on hemodynamics, lung mechanics and oxygen metabolism index. METHODS: Fifteen ARDS cases ventilated and monitored by the pulse contour method (PiCCO) were randomized into APRV group and CPAP group, then lung recruitment maneuver (RM) was executed every 4 hours. In APRV group, Phigh was 35 cm H(2)O (1 cm H(2)O=0.098 kPa) and Plow was set at lower inflection point (LIP) of the static pressure-volume (P-V) curve. In CPAP group, CPAP was also 35 cm H(2)O. The duration of RM in both groups was 40 seconds. Before and after RM the parameters of lung mechanics, oxygen metabolism index and hemodynamics were monitored and compared. RESULTS: (1) In APRV group cardiac index (CI) was decreased slightly during RM with shorter duration than CPAP group. (2) The parameters of lung mechanics and oxygenation were improved significantly in both groups, and they were better in APRV group than CPAP group. CONCLUSION: In APRV group sedation can be abstained during RM, and the hemodynamics were hardly disturbed. Improvement of lung mechanics and oxygenation is much better with APRV than CPAP mode.

[Adjustment methods of proportional pressure support on weaning during acute aggravation in chronic respiratory failure patients with chronic obstructive pulmonary disease].

OBJECTIVE: To study the effects of two adjustment methods of proportional pressure support (PPS) on patients with acute aggravation in chronic respiratory failure of chronic obstructive pulmonary disease. METHODS: Seventy-five patients were randomized to two groups, 30 in proportional adjustment group and 45 in target adjustment group, respectively. Suitable flow assist (FA) and volume assist (VA) were adjusted with proportional adjustment and target adjustment methods respectively according to the ventilation parameters until the weaning of ventilation. RESULTS: There were no significant differences in resistance, elastic, FA as well as VA on weaning point, duration of mechanical ventilation, and successful weaning rate between the two groups (all P>0.05). CONCLUSION: The same aim and successful weaning rate could be gained in the target adjustment group compared with the proportional adjustment group. More clinical experience and more intensive care would be needed in the target adjustment group.

[Preliminary analysis of treatment in 32 patients with critical severe acute respiratory syndrome].

OBJECTIVE: To summarize the experience of treatment in 32 critical severe acute respiratory syndrome (SARS) patients. METHODS: The age of 32 patients ranged from 19 to 72 years, the average was 43.06 years. Among them, 13 patients were having serious primary diseases, i.e. cardio-cerebral-vascular disease in 9 patients, diabetes in 2 patients, renal dysfunction in 1 patient, and chronic obstructive pulmonary disease (COPD) in 1 patient. The treatment included antiviral agents, glucocorticoid, mechanical ventilation, antibiotics and immunologic enhancement, etc. Cure rate, mortality and complications were analyzed. RESULTS: Among 32 patients, 24 were cured, 2 died of respiratory failure, 6 died of their primary diseases, and the overall mortality was 25.00 percent. Superimposed infection occurred in 12 patients, and among 17 patients who required noninvasive ventilation, 3 patients were complicated by lung injury (mediastinal emphysema, pneumothorax). In addition, hyperglycemia was found in 4 patients, upper intestinal hemorrhage occurred in another 4 patients and cardiac failure occurred in 6 patients. CONCLUSION: The treatment of the pre-existing diseases should be emphasized in the treatment of critical SARS. Glucocorticoid should not be used for a long-term. Vigilance should be paid to avoid lung injury during mechanical ventilation.