ABSTRACT
Acute respiratory distress syndrome (ARDS) is a common cause of critical illness and high mortality from respiratory failure. Increased dead space fraction (VD/VT) was independently associated with lung injury and mortality of ARDS. VD/VT is readily obtained by bedside measurements of arterial blood gas and end-tidal carbon dioxide. Early attention and application of VD/VT as an indicator will help to better understand the pathophysiological of ARDS, guide clinical treatment, and better assess the severity and clinical prognosis of the disease.
ABSTRACT
Objective:To investigate the therapeutic effect of different prone position ventilation (PPV) on patients with severe acute respiratory distress syndrome (ARDS) at high altitude.Methods:The severe ARDS patients who met the Berlin standard admitted to the department of intensive care unit (ICU) of Qinghai Provincial People's Hospital from January 2017 to January 2020 were enrolled. The patients with classic PPV treatment (i.e. alternate prone supine position, about 16 hours per day) were included in the discontinuous PPV group; the patients with modified PPV treatment (i.e. alternate left and right prone positions 20°-30°, every 4 hours and continuous treatment for 24 hours per day) were included in the continuous PPV group. The oxygenation index (PaO 2/FiO 2), mechanics of breathing, ventilator parameters before treatment and 72 hours after treatment, and mechanical ventilation time, the length of ICU stay, and related complications between the two groups were analyzed. Results:Eighteen cases were treated with continuous PPV and 20 cases were treated with discontinuous PPV. There were no significant differences in gender, age, acute physiology and chronic health evaluation Ⅱ (APACHEⅡ), PaO 2/FiO 2, lung compliance, driving pressure (ΔP) and positive end expiratory pressure (PEEP) before treatment between the two groups. Compared with before treatment, PaO 2/FiO 2 in discontinuous PPV group and continuous PPV group was increased significantly after 72-hour treatment [mmHg (1 mmHg = 0.133 kPa): 99.7±15.4 vs. 55.5±6.3, 121.8±25.3 vs. 55.1±7.1, both P < 0.05], lung compliance was improved significantly (mL/cmH 2O: 36.8±2.4 vs. 28.0±2.0, 43.4±6.7 vs. 27.7±2.1, both P < 0.05), and ΔP was decreased significantly [cmH 2O (1 cmH 2O = 0.098 kPa): 10.5 (10.0, 12.0) vs. 13.0 (12.3, 14.0), 10.0 (8.0, 12.0) vs. 13.0 (12.0, 14.0), both P < 0.05], PEEP was also decreased [cmH 2O: 12 (12, 14) vs. 14 (13, 14), 10 (8, 10) vs. 14 (12, 15), both P < 0.05], and the indexes in continuous PPV group were improved more significantly than those in discontinuous PPV group [PaO 2/FiO 2 (mmHg): 121.8±25.3 vs. 99.7±15.4, lung compliance (mL/cmH 2O): 43.4±6.7 vs. 36.8±2.4, ΔP (cmH 2O): 10.0 (8.0, 12.0) vs. 10.5 (10.0, 12.0), PEEP (cmH 2O): 10 (8, 10) vs. 12 (12, 14), all P < 0.05]. The duration of mechanical ventilation and the length of ICU stay in the continuous PPV group were significantly shorter than those in the intermittent PPV group [days: 6.0 (5.0, 7.3) vs. 8.0 (7.0, 9.0), 9.7±1.5 vs. 12.1±2.2, both P < 0.01]. During the PPV treatment, there were 3 cases of cheek skin damage and 2 cases of ear skin damage in the continuous PPV group, and 3 cases of facial skin damage in the intermittent PPV group. There was no significant difference in the incidence of complications between the two groups ( χ2 = 0.321, P = 0.571). All patients were repaired normally after PPV, without adverse consequences. Conclusion:Continuous PPV is more effective than discontinuous PPV in the treatment of severe ARDS patients at high altitude, and the related complications are did not increased in prolonged time of PPV.
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Objective To observe the changes in microcirculation after induction of anesthesia in patients in plateau region. Methods Ten patients of both sexes, aged 35-58 yr, weighing 52-87 kg, of American Society of Anesthesiologists physical statusⅠ or Ⅱ, were enrolled in this study. Anesthesia was induced with intravenous etomidate 0. 3 mg∕kg, sufentanil 0. 75 μg∕kg and vecuronium 0. 10 mg∕kg. Me-chanical ventilation was performed after tracheal intubation. Fluid was replaced by intravenously infusing lactated Ringer′s solution 500 ml over 30-45 min after completion of anesthesia induction. At 5 min before anesthesia induction, 5 min after induction and after the end of fluid replacement, the hemodynamic pa-rameters such as heart rate (HR), SpO2and mean arterial pressure (MAP) were recorded, and microcir-culatory indices such as total vascular density (TVD), perfused vessel density (PVD), proportion of per-fused small vessels (PPV) and microvascular flow index (MFI) were measured. Results Compared with the baseline value before anesthesia induction, HR was significantly increased, SpO2and MAP were de-creased, TVD, PVD, PPV and MFI were decreased at 5 min after anesthesia induction (P＜0. 05). Com-pared with the baseline value at 5 min after anesthesia induction, HR was significantly decreased, and SpO2and MAP were increased immediately after fluid replacement (P＜0. 05), and no significant change was found in TVD, PVD, PPV or MFI immediately after fluid replacement (P＞0. 05). Conclusion Mi- crocirculatory disturbance is obvious after induction of general anesthesia in patients undergoing operation in plateau region, and no marked improvement is found in microcirculation after rapid fluid replacement, which may be the main cause of metabolic disorders such as acidosis after operation.
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In order to learn the tissuse perfusion and oxygenization in the patient with septic shock (SS) in Qinghai plateau,25 cases having suffered from SS in Xining,the capital of Qinghai province, were divided into death group (group D) and survival group(group S), and the data of oxygen dynamics, determined by Swan-Ganz cathter and thermodilution methods,were analyzed retrospectively. The results showed that the oxygen delivery (DO_2) and oxygen consumption (VO_2) increased to varying degrees in all of cases;VO_2 was positively correlated with DO_2, and in group D the correlation remained significant during whole duration of disease,but in group S it became unsignificant as DO_2 was above 700 ml?min~(-1)?m~(-2); the oxygen extraction rate decreased markedly in both groups,but much more in group D. These suggest that the insufficient oxygenization of general tissuse in patient with SS results from the dysfunction of oxygen extraction,and increasing DO_2 is helpful for the shock resuscitation except VO_2 is persistently and positively correlatded with DO_2.