Respiratory muscle strength should be continuously monitored for patients on mechanical ventilation / 中华危重病急救医学

Mechanical ventilation (MV) is an effective treatment for respiratory failure. In recent years, it has been found that MV can not only cause ventilation-associated lung injury (VALI), but also cause ventilation-induced diaphragmatic dysfunction (VIDD). Although the injury site and etiology are not the same, they are interrelated and mutually causal, and eventually lead to weaning failure. Studies have indicated that diaphragmatic function protection strategy should be implemented in patients on MV. That is, the entire process from assessing the ability of spontaneous breathing before MV, to the initiation of spontaneous breathing and to weaning during MV. For patients on MV, continuous monitoring of respiratory muscle strength should be conducted. Early prevention, early intervention and timely detection of VIDD may reduce the occurrence of difficult weaning, resulting in improved prognosis. This study mainly discussed the risk factors and pathogenesis of VIDD.

Volume dynamics and volume management in intensive care unit patients / 中华危重病急救医学

Volume dynamics is a two-compartment dynamical model using hemoglobin (Hb) derived plasma diluted level as input data and urine output as input variable through consecutive repeated measurements of Hb concentration in the blood during infusion. It could be applied to evaluate and guide crystalloid fluid rehydration for patients with dehydration or hypovolemia and during anesthesia or surgery. Volume dynamics could be also used to quantificate of strains, hypovolume, and the change of fluid distribution and elimination caused by anesthesia or surgery. The factors which influence the volume resuscitation are complex, including gender, age, hemodynamic state [mean arterial pressure (MAP)], health and stress state, renal function, consciousness, surgical or anesthesia state and so on, which may affect the half-life, distribution, and volume of the fluid. This article summarizes and analyzes the pathophysiological changes of crystalloids fluid in vivo, in order to provide reference for volume management in critically ill patients.

Accurate evaluation of mechanical ventilation and spontaneous respiratory activity / 中华危重病急救医学

Maintenance of spontaneous effort during mechanical ventilation has long been recognized to improve oxygenation. Such effort has been considered beneficial because oxygenation is a key management aim. However, accumulating evidence indicates that spontaneous effort during mechanical ventilation may cause or worsen acute lung injury. Recently, effort-dependent lung injury has been termed as patient-self inflicted lung injury (P-SILI). This paper describes pathophysiological changes of ventilation-induced lung injury (VILI) induced by mechanical ventilation and spontaneous breathing, and the role of spontaneous breathing during mechanical ventilation in acute respiratory distress syndrome (ARDS). Studies have shown that spontaneous breathing is a double-edged sword, depending on the intensity of spontaneous breathing activity and the severity of lung injury. Future studies are needed to determine ventilator strategies minimizing injury.

Diamond-shaped anastomosis in Ivor Lewis minimally invasive esophagectomy for esophageal carcinoma / 中华普通外科杂志

Objective To evaluate initial results of Ivor Lewis minimally invasive esophagectomy (MIE) for esophageal carcinoma using a diamond-shaped anastomosis with 45 mm linear-stapler.Methods Clinical data of 12 patients diagnosed middle to distal esophageal carcinoma and undergoing Ivor Lewis minimally invasive esophagetomy using a diamond-shaped anastomosis technique during Dec.2015 and Nov.2016 in Peking Union Medical College Hospital were collected and analyzed retrospectively.Results The mean operation time was (378 ± 56) min,the mean blood loss was (280 ± 120) ml,and the mean postoperative hospital stay was (12.2 ± 2.0) days.No positive margin,no peri-operative death occurred.Postoperative complication included atelectasis and pulmonary infection in 1 patient,paresis of left recurrent laryngeal nerve in 1 patient.No anastomotic leak or constriction occurred.Median follow up was 7 months,11 patients had no evidence of disease progress,1 patient had subcutanecous metastasis and was reoperated.Conclusion The diamond anastomosis technique utilizing in Ivor Lewis MIE for esophageal carcinoma is feasible,easy to manipulate,safe and reliable.

Assessment of fluid volume in critically ill patients with extravascular lung water index / 中华危重病急救医学

Objective To examine the effect of rapid infusion test guided by extravascular lung water index (EVLWI) on hemodynamics in critically ill patients at different states in order to guide volume resuscitation.Methods A prospective observation was conducted.Forty critically ill patients admitted to Department of Critical Care Medicine of Tianjin Third Central Hospital from June 2012 to April 2014 were enrolled.Based on the levels of EVLWI and pulmonary vascular permeability index (PVPI) and the cardiac function,the patients were divided into four groups:septic patients with normal EVLWI and PVPI (n =17),septic patients with increased EVLWI and PVPI (n =3),septic patients with increased EVLWI and normal PVPI (n =4),and coronary heart disease and heart failure patients with normal EVLWI and PVPI (n =16).The rapid infusion test was conducted in all patients using lactated Ringer solution 250 mL,followed by infusion of crystalloid with rate of 150 mL/h.The conditions of mechanical ventilation and vasoactive drugs were not changed during study.The changes in EVLWI,intrathoracic blood volume index (ITBVI),and cardiac index (CI) before capacity load,at immediate capacity load,and 15,45,105 minutes after load were determined by pulse indicator continuous cardiac output (PiCCO).On the base of volume status before and after the liquid infusion,the standard for the changes were:stroke volume (SV) increased by 12％-15％,central venous pressure (CVP) greater ≥ 2 mmHg (1 mmHg =0.133 kPa),CI ＞ 15％,and ITBVI change greater than 10％.Results There were no statistically significant differences in the observed indicators at the each time point before and after rapid infusion test among the four groups (all P ＞ 0.05).In septic patients with normal EVLWI and PVPI group,ITBVI was slightly increased by 5.4％-9.7％ from 15 minutes to 45 minutes after rapid infusion test.In coronary heart disease and heart failure patients with normal EVLWI and PVPI group,the EVLWI was increased by 11.9％,5.9％,and 14.7％ respectirely at 15,45,and 105 minutes,ITBVI was slightly increased by 6.4％ at 45 minutes,CI was increased by 29.5％ immediately after rapid infusion.In septic patients with increased EVLWI and PVPI group,CVP was increased by 8 mmHg immediately,EVLWI was increased significantly by 15.8％ at 45 minutes,ITBVI was slightly decreased by 10.0％ at 45 minutes,CI was increased by 24.7％ immediately,and increased by 17.0％ at 105 minutes,and PVPI was increased by 15.6％-28.1％ at 15-105 minutes after rapid infusion.In septic patients with increased EVLWI and normal PVPI group,CVP was increased by 1.5 mmHg at 15 minutes,EVLWI was increased immediately,which was increased by 17.4％,24.0％,and 31.4％ respectively at 15,45,and 105 minutes,ITBVI was increased by 13.9％ at 15 minutes,CI was increased by 16.1％ at 15 minutes after rapid fluid infusion.Conclusions Rapid fluid replacement in critically ill patients with crystalloid,regardless of whether the EVLWI was normal or increased,the short-term response was affected by the volume and cardiac function of patients.Different status of patients showed different volume effect curve:no significant changes in hemodynamic parameters were found in patients with normal EVLWI and volume parameters.In patients with potential cardiac dysfunction,CI and EVLWI increased significantly; regardless of PVPI increased or normal,EVLWI and CI were increased in patients with elevated EVLWI; two different changes could be found in the two types of pulmonary edema while ITBVI was increased.

The influence of continuous venovenous hemofiltration on parameter measurement by the transpulmonary thermodilution technique / 中华危重病急救医学

ObjectiveTo evaluate the influence of continuous venovenous hemofiltration (CVVH) on measurement of transpulmonary thermodilution parameters.MethodsA prospective observational study was conducted. Fifty-six patients who received CVVH and hemodynamic monitoring at the same time admitted to the Department of Critical Care Medicine of Tianjin Third Central Hospital from July 2012 to July 2014 were enrolled. In all the patients, the dialysis catheter was inserted through the femoral vein, and transpulmonary thermodilution measurements were performed by pulse indicator continuous cardiac output (PiCCO) monitoring technology at the same time. Mean arterial pressure (MAP), central blood temperature, cardiac index (CI), global end-diastolic volume index (GEDVI), intrathoracic blood volume index (ITBVI) and extravascular lung water index (EVLWI) were measured before CVVH, immediately after CVVH, and 30 minutes after CVVH, respectively.Results In the 56 patients, there were 36 males and 20 females, (66±16) years of old, height of (172±6) cm, body weight of (68±10) kg. The acute physiology and chronic health evaluationⅡ (APACHEⅡ) scores was 26±6. After CVVH,the central blood temperature was gradually decreased, and blood temperature at 30 minutes after CVVH was significantly lower than that before CVVH (℃: 37.17±1.06 vs. 37.57±1.26,P 0.05]. CI, GEDVI, ITBVI at 30 minutes after CVVH were significantly decreased [CI (mL·s-1·m-2): 57.84±20.50 vs. 63.85±21.84, GEDVI (mL/m2):681±106 vs. 727±100, ITBVI (mL/m2): 851±133 vs. 908±125, allP< 0.05]. CVVH was associated with a decline of 6.01 mL·s-1·m-2 at 30 minutes after CVVH [95% confidence interval (95%CI) = -10.67 to -1.50,P = 0.011]. The declines of GEDVI and ITBVI were observed with 46 mL/m2 (95%CI = -81 to - 11,P = 0.014), 57 mL/m2 (95%CI =-101 to - 13,P = 0.014 ) respectively 30 minutes after CVVH.Conclusions CVVH had no significant effect on the transpulmonary thermodilution measurements of CI, GEDVI, ITBVI and EVLWI. Thirty minutes after the start of CVVH, CI, GEDVI and ITBVI was decreased significantly, but had no effect on EVLWI.