Postoperative pulmonary bleeding and reperfusion pulmonary edema in an adult patient after repair of tetralogy of Fallot with pulmonary atresia--percutaneous cardiopulmonary support (PCPS) and lung protective ventilatory strategy

After total correction of tetralogy of Fallot, pulmonary atresia and major aorto-pulmonary collateral arteries, a 31-year-old man developed life-threatening pulmonary hypertension and reperfusion pulmonary edema, leading to pulmonary hemorrhage, right heart failure and hypoxia. Because of difficulty in weaning from cardiopulmonary bypass and in controlling hemorrhage from pulmonary arteries, we applied percutaneous cardiopulmonary support (PCPS) for 281 hours with strategy of delayed sternal closure (17 days) and a large quantity of transfusion. We also applied lung protective ventilatory strategy for reperfusion pulmonary edema (high PEEP, limited peak inspiratory pressure and recruitment maneuver). As the result, he was discharged alive without any major complications. We report our postoperative managements, in terms of 1) lung protective ventilatory strategy, 2) surgical control of pulmonary blood flow, and 3) evaluation of the cardiopulmonary function during PCPS for early weaning from PCPS.     

Anesthetic management of massive endobronchial hemorrhage after pulmonary embolectomy

We report a case of massive endobronchial hemorrhage after pulmonary embolectomy. A 63-year-old woman underwent emergency pulmonary embolectomy with cardiopulmonary bypass (CPB). During partial CPB, we found massive blood gushing out from the endotracheal tube. Approximately 2,000 ml of blood was aspirated in 10 minutes. To ensure adequate oxygenation, emergent percutaneous cardiopulmonary support system (PCPS) was started. After neutralization of heparin and the institution of 10 cmH2O of positive end-expiratory pressure, the bleeding diminished. Institution of PCPS allows performance of unhurried bronchoscopy to identify the actual bleeding point and to lavage the airway. In addition to this management, we administrated steroids and neutrophil elastase inhibitor to stabilize pulmonary capillary membrane. Without complications, the patient was extubated 2 days after operation and the following course was uneventful. Immediate institution of PEEP and pharmacological interventions to reduce pulmonary blood pressure were beneficial in arresting hemorrhage. The bleeding begins usually at the time of discontinuation of CPB. We should recognize the possible occurrence of endobronchial bleeding after pulmonary embolectomy and prepare to protect the airway and to maintain oxygenation and cardiac function.     

A case of delayed diagnosis of pulmonary thromboembolism in a patient with mitral stenosis undergoing cesarean section

Cesarean section was performed under general anesthesia in a 38-year-old patient with congestive heart failure due to severe mitral stenosis. During surgery, pulmonary hypertension, right ventricular distension and the dissociation of PETCO2 and PaCO2 were observed. However, pulmonary thromboembolism (PTE) was proved after the operation when she developed severe hypotension in the intensive care unit. Although she recovered once from circulatory unstability with the use of percutaneous cardiopulmonary support (PCPS) and she could be weaned from PCPS at the 4th postoperative day, she died from tracheal bleeding and recurrent cardiopulmonary collapse 22nd day after the surgery. It should be noted that the increasing dissociation of PETCO2 and PaCO2 may be an early sign of PTE even in a patient with severe mitral stenosis and pulmonary hypertension.     

Effects of lung recruitment maneuver and positive end-expiratory pressure on lung volume,respiratory mechanics and alveolar gas mixing in patients ventilated after cardiac surgery

BACKGROUND: It is unclear whether positive end-expiratory pressure (PEEP) is needed to maintain the improved oxygenation and lung volume achieved after a lung recruitment maneuver in patients ventilated after cardiac surgery performed in the cardiopulmonary bypass (CPB). METHODS: A prospective, randomized, controlled study in a university hospital intensive care unit. Sixteen patients who had undergone cardiac surgery in CPB were studied during the recovery phase while still being mechanically ventilated with an inspired fraction of oxygen (FiO2) 1.0. Eight patients were randomized to lung recruitment (two 20-s inflations to 45 cmH2O), after which PEEP was set and kept for 2.5 h at 1 cmH2O above the pressure at the lower inflexion point (14+/-3 cmH2O, mean +/-SD) obtained from a static pressure-volume (PV) curve (PEEP group). The remaining eight patients were randomized to a recruitment maneuver only (ZEEP group). End-expiratory lung volume (EELV), series dead space, ventilation homogeneity, hemodynamics and PaO2 (oxygenation) were measured every 30 min during a 3-h period. PV curves were obtained at baseline, after 2.5 h, and in the PEEP group at 3 h. RESULTS: In the ZEEP group all measures were unchanged. In the PEEP group the EELV increased with 1220+/-254 ml (P<0.001) and PaO2 with 16+/-16 kPa (P<0.05) after lung recruitment. When PEEP was discontinued EELV decreased but PaO2 was maintained. The PV curve at 2.5 h coincided with the curve obtained at 3 h, and both curves were both steeper than and located above the baseline curve. CONCLUSIONS: Positive end-expiratory pressure is required after a lung recruitment maneuver in patients ventilated with high FiO2 after cardiac surgery to maintain lung volumes and the improved oxygenation.     

Evaluation of a recruitment maneuver with positive inspiratory pressure and high PEEP in patients with severe ARDS

BACKGROUND: To evaluate the effect of a recruitment maneuver (RM) with constant positive inspiratory pressure and high positive end-expiratory pressure (PEEP) on oxygenation and static compliance (Cs) in patients with severe acute respiratory distress syndrome (ARDS). METHODS: Eight patients with ARDS ventilated with lung-protective strategy and an arterial partial pressure of oxygen to inspired oxygen fraction ratio (PaO2/FIO2) < or =100 mmHg regardless of PEEP were prospectively studied. The RM was performed in pressure-controlled ventilation at FIO2 of 1.0 until PaO2 reached 250 mmHg or a maximal plateau pressure/PEEP of 60/45 cmH2O was achieved. The RM was performed with stepwise increases of 5 cmH2O of PEEP every 2 min and thereafter with stepwise decreases of 2 cmH2O of PEEP every 2 min until a drop in PaO2 >10% below the recruitment PEEP level. Data was collected before (preRM), during and after 30 min (posRM). RESULTS: The PaO2/FIO2 increased from 83 +/- 22 mmHg preRM to 118 +/- 32 mmHg posRM (P = 0.001). The Cs increased from 28 +/- 10 ml cmH2O(-1) preRM to 35 +/- 12 ml cmH2O(-1) posRM (P = 0.025). The PEEP was 12 +/- 3 cmH2O preRM and was set at 15 +/- 4 cmH2O posRM (P = 0.025). The PEEP of recruitment was 36 +/- 9 cmH2O and the collapsing PEEP was 13 +/- 4 cmH2O. The PaO2 of recruitment was 225 +/- 105 mmHg, with five patients reaching a PaO2 > or = 250 mmHg. The FIO2 decreased from 0.76 +/- 0.16 preRM to 0.63 +/- 0.15 posRM (P = 0.001). No major complications were detected. CONCLUSION: Recruitment maneuver was safe and useful to improve oxygenation and Cs in patients with severe ARDS ventilated with lung-protective strategy.     

Effect of respiratory care on pulmonary function in patients after cardiopulmonary bypass

BACKGROUND: Respiratory failure after cardiopulmonary bypass (CPB) remains one of the major complications after cardiac surgery. This study was designed to evaluate effects of respiratory care after CPB on pulmonary function. METHODS: Eighteen patients scheduled for cardiac surgery were investigated. Preoperative respiratory functions (%VC, FEV1.0%, V25/Ht, FRC-CC, deltaN2) were measured in all the patients. Both induction and maintenance of anesthesia were performed using propofol, midazolam, fentanyl, and vecuronium bromide. All the patients were ventilated using volume controlled ventilation by setting FIO2 at 0.5, the respiratory frequency at 15 x min(-1), the tidal volume at 6-10 ml x kg(-1) adjusted to maintain PaCO2 between 30 to 40 mmHg, and the peak airway pressures below 40 cmH2O, PEEP of 0 cmH2O. From 1 hour after the operation, the patients were randomly divided into 2 groups: group A, ventilated artificially with PEEP of 5 cmH2O and group B, ventilated with PEEP adjusted to the patient's lower inflection point (LIP) obtained by the pressure-volume curve. PaO2, Qs/Qt and FRC were measured after induction of anesthesia, just after surgery, 1 hour after surgery and 1 hour after artificial ventilation with PEEP. The values of the LIP were obtained from the P-V curves with the constant-flow methods before and after surgery. RESULTS: PaO2 and FRC decreased and Qs/Qt increased significantly after the surgery in all the patients. One hour after artificial ventilation with PEEP, PaO2 increased and Qs/Qt decreased significantly compared with the values after operation. However, there was no significant difference in the magnitude of these changes among the different groups. The changes in PaO2 and Qs/Qt were not correlated with the changes in FRC and preoperative respiratory functions. The LIP tended to increase after surgery in 2 groups. CONCLUSIONS: Although pulmonary function deteriorated after CPB. PEEP could improve oxygenation in all the patients. There were no significant differences in the degree of these improvements between patients receiving PEEP of 5 cmH2O and patients with PEEP adjusted to their LIP. There was no significant relationship between preoperative pulmonary function and changes in oxygenation after CPB.     

不同水平呼气末正压通气对肥胖患者围术期呼吸功能的影响

目的 评价不同水平呼气末正压(PEEP)通气对肥胖患者胃减容手术围术期呼吸功能的影响.方法 选择2018年3月至2019年12月于我院行择期腹腔镜下胃减容手术肥胖患者70例,男43例,女27例,年龄28～52岁,BMI 34～43 kg/m2,ASAⅡ或Ⅲ级.采用随机数字表法将患者分为两组:PEEP 10 cmH2 O...     

利用动态肺顺应性设定呼气末正压在胸腔镜肺叶切除术中的运用

目的 探讨单肺通气利用动态肺顺应性设定呼气末正压通气(positive end-expiratory pressure,PEEP)的优势及可行性. 方法 选择预行右侧肺叶切除患者80例,完全随机分为A组和B组,每组40例:A组,单肺通气实施肺膨胀(sustained inflation,SI)复张后加用20 cmH2O(1 cmH2O=0.098 kPa)的PEEP并递减滴定,随后以得到最大肺顺应性的PEEP值通气,直到恢复双肺通气;B组,通气PEEP值固定为5 cmH2O,其他通气方法同A组.记录患者血气、呼吸等参数. 结果 两组设定的PEEP值[A组(9.2±1.2) cmH2O,B组5 cmH2O]差异有统计学意义(P＜0.05);在单肺通气1 h(T3)、手术结束(T4)时,两组动脉血氧分压(partial pressure of oxygen,PaO2)比较,差异有统计学意义(P＜0.05);B组的PaO2在T3～T4逐步降低,差异有统计学意义(P＜0.05),而A组则维持较好(P＞0.05);T3、T4时刻A组的动态肺顺应性[(30.8±5.9)、(30.7±6.4) ml/cmH2O]与B组[(26.6±5.5)、(26.4±5.2) ml/cmH2O]比较,差异有统计学意义(P＜0.05). 结论 胸腔镜肺叶切除术中的单肺通气,利用动态肺顺应性设定的PEEP值通气能够得到更好的氧合及呼吸参数,并且维持较好.     

Alveolar recruitment maneuver in refractory hypoxemia and lobar atelectasis after cardiac surgery: A case report

ABSTRACT: OBJECTIVE: This case report describes an unusual presentation of right upper lobe atelectasis associated with refractory hypoxemia to conventional alveolar recruitment maneuvers in a patient soon after coronary artery bypass grafting surgery. METHOD: Case-report. RESULTS: The alveolar recruitment with PEEP = 40cmH2O improved the patient's atelectasis and hypoxemia. CONCLUSION: In the present report, the unusual alveolar recruitment maneuver with PEEP 40cmH2O showed to be safe and efficient to reverse refractory hypoxemia and uncommon atelectasis in a patient after cardiac surgery.     

肺泡复张术和呼气末正压通气对后腹腔镜术后早期呼吸功能的影响

目的探讨肺泡复张术（RM）复合呼气末正压通气（PEEP）是否能有效改善后腹腔镜手术后早期呼吸功能。方法 30例择期后腹腔镜手术患者,随机分为3组行不同的术中通气方式：对照组（n=10）行常规正压通气;PEEP组（n=10）正压通气加呼气末正压（PEEP）4 cmH2O;PEEP＋RM组（n=10）通气方式与PEEP组相同,在气腹结束后立即以30 cmH2O压力维持30s气道正压行肺泡复张术。在气腹前（Baseline）、气腹后10 min（PI 10 min）、气腹后30 min（PI 30 min）、气腹后60 min（PI 60 min）、放气腹后1 min（PD1 min）、拔管后5 min（EX 5 min）、拔管后0.5h（EX 30 min）等7个时点检测记录呼气末CO （2ETCO2）、动脉血气分析并计算动脉与呼气末CO2差值[D（a-e）CO2]、氧合指数（OI）等。结果与对照组相比,PEEP、PEEP＋RM两组在PI 60 min和PD1 min两个时点的Pa CO2显著降低（P〈0.005）。PEEP组与PEEP＋RM组在PI 30 min、PI 60 min和EX 30 min等时点,其D（a-e）CO2均显著低于对照组（P〈0.05）。在EX 5 min和EX 30 min两时点,PEEP＋RM组的OI则显著高于对照组（P〈0.05）;而两时点间Pa-CO2的差值ΔPaCO2在PEEP＋RM组显著高于对照组（P〈0.05）。结论术中使用PEEP可有效减少动脉血和肺泡的CO2分压差,减少肺泡塌陷;肺泡复张术可在拔管后有效加快动脉血CO2分压的下降并改善氧合指数。复合以上两种处理,可有效减轻后腹腔镜术后早期CO2蓄积,促进呼吸功能恢复。     

Both lung recruitment maneuver and PEEP are needed to increase oxygenation and lung volume after cardiac surgery

BACKGROUND: Patients ventilated after cardiac surgery commonly have impaired oxygenation, mainly due to lung collapse. We have previously found that PaO2 and end-expiratory lung volume (EELV) were increased by a lung recruitment maneuver (LRM) followed by positive end-expiratory pressure (PEEP). The aim of this study was to evaluate whether only PEEP or only a LRM could give similar effects. METHODS: Thirty circulatory stable patients (aged 55-79 years) mechanically ventilated after cardiac surgery were randomized to receive LRM (four 10-s insufflations to an airway pressure of 45 cmH2O) and zero end-expiratory pressure (LRM-group), PEEP 12 cmH2O (PEEP-group) or LRM in combination with PEEP 12 cmH2O (LRM + PEEP-group). The set end-expiratory pressure was kept for 75 min. Before, during and after the intervention, EELV (SF6 washout technique) and blood gases were measured. RESULTS: Initial EELV and PaO2 were similar in all groups. In the LRM-group, PaO2 and EELV increased transiently (P < 0.0001), but returned at 5 min to the initial values. In the PEEP-group, PaO2 did not change but EELV increased to 155 +/- 27% of the initial value (P < 0.0001). In the LRM+PEEP-group, PaO2 and EELV increased to 212 +/- 66% and 178 +/- 31% of the initial values (P < 0.0001), respectively, and were maintained during PEEP application. CONCLUSION: In patients ventilated after cardiac surgery: (1) PEEP increased lung volume but not PaO2, (2) a lung recruitment maneuver without subsequent PEEP had no sustained effect, and (3) both a lung recruitment maneuver and PEEP were needed to increase and maintain the increased lung volume and PaO2.     

Alveolar recruitment in pulmonary and extrapulmonary acute respiratory distress syndrome: comparison using pressure-volume curve or static compliance

BACKGROUND: Alveolar recruitment in response to positive end-expiratory pressure (PEEP) may differ between pulmonary and extrapulmonary acute respiratory distress syndrome (ARDS), and alveolar recruitment values may differ when measured by pressure-volume curve compared with static compliance. METHODS: The authors compared PEEP-induced alveolar recruitment in 71 consecutive patients identified in a database. Patients were classified as having pulmonary, extrapulmonary, or mixed/uncertain ARDS. Pressure-volume curves with and without PEEP were available for all patients, and pressure-volume curves with two PEEP levels were available for 44 patients. Static compliance was calculated as tidal volume divided by pressure change for tidal volumes of 400 and 700 ml. Recruited volume was measured at an elastic pressure of 15 cm H2O. RESULTS: Volume recruited by PEEP (10 +/- 3 cm H2O) was 223 +/- 111 ml in the pulmonary ARDS group (29 patients), 206 +/- 164 ml in the extrapulmonary group (16 patients), and 242 +/- 176 ml in the mixed/uncertain group (26 patients) (P = 0.75). At high PEEP (14 +/- 2 cmH2O, 44 patients), recruited volumes were also similar (P = 0.60). With static compliance, recruitment was markedly underestimated and was dependent on tidal volume (226 +/- 148 ml using pressure-volume curve, 95 +/- 185 ml for a tidal volume of 400 ml, and 23 +/- 169 ml for 700 ml; P < 0.001). CONCLUSION: In a large sample of patients, classification of ARDS was uncertain in more than one third of patients, and alveolar recruitment was similar in pulmonary and extrapulmonary ARDS. PEEP levels should not be determined based on cause of ARDS.     

Acute massive pulmonary thromboembolism treated with percutaneous cardiopulmonary support perioperatively

A 57-year-old female was transferred to our hospital because of sudden dyspnea. She was hypotensive and hypoxic. Acute massive pulmonary thromboembolism was detected by echocardiography and computed tomography (CT). Before the operation, she fell into severe shock and needed cardiopulmonary resuscitation. We applied percutaneous cardiopulmonary support (PCPS), and performed emergency open embolectomy under total cardiopulmonary bypass. Because of the right ventricular failure, she could not be weaned from total cardiopulmonary bypass. PCPS was required again and used continuously during postoperative management. Her cardiopulmonary state improved gradually. PCPS was stopped at 6 days after surgery, and she was extubated at 14 days after surgery. PCPS was very useful for resuscitation and stabilization of the cardiopulmonary function for acute massive pulmonary thromboembolism perioperatively.     

Alveolar recruitment strategy improves arterial oxygenation after cardiopulmonary bypass

Atelectasis occurs during general anaesthesia. This is partly responsible for the impairment of gas exchange that occurs peri-operatively. During cardiopulmonary bypass, this atelectasis is exacerbated by the physical collapse of the lungs. As a result, poor arterial oxygenation is often seen postoperatively. We tested the effect of an 'alveolar recruitment strategy' on arterial oxygenation in a prospective randomised study of 78 patients undergoing cardiopulmonary bypass. Patients were divided equally into three groups of 26. Group 'no PEEP' received a standard post bypass manual lung inflation, and no positive end-expiratory pressure was applied until arrival at intensive care unit. Group '5 PEEP' received a standard post bypass manual inflation, and then 5 cmH2O of positive end-expiratory pressure was applied and maintained until extubation on intensive care. The third group, 'recruitment group', received a pressure-controlled stepwise increase in positive end-expiratory pressure up to 15 cmH2O and tidal volumes of up to 18 ml x kg(-1) until a peak inspiratory pressure of 40 cmH2O was reached. This was maintained for 10 cycles; the positive end-expiratory pressure of 5 cmH2O was maintained until extubation on intensive care. There was a significantly better oxygenation in the recruitment group at 30 min and 1 h post bypass when compared with the no PEEP and 5 PEEP groups. There was no significant difference in any of the groups beyond 1 h. Application of 5 cmH2O positive end-expiratory pressure alone had no significant effect on oxygenation. No complications due to the alveolar recruitment manoeuvre occurred. We conclude that the application of an alveolar recruitment strategy improves arterial oxygenation after cardiopulmonary bypass surgery.     

Effects of positive end expiratory pressure on oxygen transport

Fifteen patients admitted at the ICU of our hospital suffering from respiratory failure and submitted to mechanical ventilation were included in a study upon the influence of positive end expiratory pressure (PEEP) on oxygen transport. When the PaO2/FiO2 index was less than 300, 200, and 150, PEEP of +5, +10, and +15 cmH2O respectively was introduced. A Swan-Ganz catheter in the pulmonary artery and a catheter in a radial artery were inserted with the aim to obtain mixed venous blood samples and determine cardiac output, and vascular pulmonary resistances for each PEEP value. When PEEP increased from 5 cmH2O to 15 cmH2O, oxygen supply decreased a 12.4% (p less than 0.05), oxygen extraction from the tissues increased a 21.4% (p less than 0.025) and cardiac output decreased a 7.9% (p less than 0.02) while vascular pulmonary resistances increased a 6.6% (p = NS). We conclude that a PEEP of 5 cmH2O impairs tissue oxygenation when compared with PEEP of 5 cmH2O and that oxygen supply decrease with cardiac output.     

Recruitment maneuvers after a positive end-expiratory pressure trial do not induce sustained effects in early adult respiratory distress syndrome

BACKGROUND: Recruitment maneuvers performed in early adult respiratory distress syndrome remain a matter of dispute in patients ventilated with low tidal volumes and high levels of positive end-expiratory pressure (PEEP). In this prospective, randomized controlled study the authors evaluated the impact of recruitment maneuvers after a PEEP trial on oxygenation and venous admixture (Qs/Qt) in patients with early extrapulmonary adult respiratory distress syndrome. METHODS: After a PEEP trial 30 consecutive patients ventilated with low tidal volumes and high levels of PEEP were randomly assigned to either undergo a recruitment maneuver or not. Data were recorded at baseline, 3 min after the recruitment maneuver, and 30 min after baseline. Recruitment maneuvers were performed with a sustained inflation of 50 cm H2O maintained for 30 s. RESULTS: Compared with baseline the ratio of the arterial oxygen partial pressure to the fraction of inspired oxygen (Pao2/Fio2) and Qs/Qt improved significantly at 3 min after the recruitment maneuver (Pao2/Fio2, 139 +/- 46 mm Hg versus 246 +/- 111 mm Hg, P < 0.001; Qs/Qt, 30.8 +/- 5.8% versus 21.5 +/- 9.7%, P < 0.005), but baseline values were reached again within 30 min. No significant differences in Pao2/Fio2 and Qs/Qt were detected between the recruitment maneuver group and the control group at baseline and after 30 min (recruitment maneuver group [n = 15]: Pao2/Fio2, 139 +/- 46 mm Hg versus 138 +/- 39 mm Hg; Qs/Qt, 30.8 +/- 5.8% versus 29.2 +/- 7.4%; control group: [n = 15]: Pao2/Fio2, 145 +/- 33 mm Hg versus 155 +/- 52 mm Hg; Qs/Qt, 30.2 +/- 8.5% versus 28.1 +/- 5.4%). CONCLUSION: In patients with early extrapulmonary adult respiratory distress syndrome who underwent a PEEP trial, recruitment maneuvers failed to induce a sustained improvement of oxygenation and venous admixture.     

Alveolar Recruitment in Pulmonary and Extrapulmonary Acute Respiratory Distress Syndrome: Comparison Using Pressure-Volume Curve or Static Compliance

Background: Alveolar recruitment in response to positive end-expiratory pressure (PEEP) may differ between pulmonary and extrapulmonary acute respiratory distress syndrome (ARDS), and alveolar recruitment values may differ when measured by pressure-volume curve compared with static compliance.

Methods: The authors compared PEEP-induced alveolar recruitment in 71 consecutive patients identified in a database. Patients were classified as having pulmonary, extrapulmonary, or mixed/uncertain ARDS. Pressure-volume curves with and without PEEP were available for all patients, and pressure-volume curves with two PEEP levels were available for 44 patients. Static compliance was calculated as tidal volume divided by pressure change for tidal volumes of 400 and 700 ml. Recruited volume was measured at an elastic pressure of 15 cm H2O.

Results: Volume recruited by PEEP (10 +/- 3 cm H2O) was 223 +/- 111 ml in the pulmonary ARDS group (29 patients), 206 +/- 164 ml in the extrapulmonary group (16 patients), and 242 +/- 176 ml in the mixed/uncertain group (26 patients) (P = 0.75). At high PEEP (14 +/- 2 cmH2O, 44 patients), recruited volumes were also similar (P = 0.60). With static compliance, recruitment was markedly underestimated and was dependent on tidal volume (226 +/- 148 ml using pressure-volume curve, 95 +/- 185 ml for a tidal volume of 400 ml, and 23 +/- 169 ml for 700 ml; P < 0.001).     

Derecruitment of the lung induced by stepwise lowering of positive end-expiratory pressure in patients with adult respiratory distress syndrome

BACKGROUND AND OBJECTIVE: It has recently been suggested that recruitment proceeds far above the lower inflection point of the elastic pressure-volume (Pel/V) curve of the respiratory system. Accordingly, the value of the lower inflection point as a guide to set the positive end-expiratory pressure (PEEP) has been challenged. Our aim was to evaluate the derecruitment induced by stepwise decreasing PEEP levels. METHODS: Seven consecutive sedated and paralysed patients with acute respiratory distress syndrome were studied. Multiple Pel/V curves of the respiratory system were recorded at PEEP levels progressively decreasing in steps of 3.75 cmH2O from + 15 to zero according to the principles of the low flow inflation method. RESULTS: Multiple Pel/V curves shifted towards lower volumes at decreasing PEEP. Dynamic compliance was higher for Pel/V curves recorded from lower PEEP levels. A high correlation (r = 0.99) was found between dynamic compliance and PEEP. The lower inflection point was on average 9.2 cmH2O. However, the transition between the lower segment and the linear part of the Pel/V curve was in general smooth to the eye. The upper inflection point was on average 23.8 cmH2O. A high correlation (r = 0.98) between the upper inflection point and PEEP was found. CONCLUSIONS: The lower inflection point is a poor indicator of alveolar closure. The evaluation of derecruitment induced by a stepwise reduction in PEEP seems to be more useful than individual titration of PEEP and tidal volume in patients with adult respiratory distress syndrome.     

Pulmonary acute respiratory distress syndrome: positive end-expiratory pressure titration needs stress index

Background

The heterogeneity of lung injury in pulmonary acute respiratory distress syndrome (ARDS) may have contributed to the greater response of hyperinflated area with positive end-expiratory pressure (PEEP). PEEP titrated by stress index can reduce the risk of alveolar hyperinflation in patients with pulmonary ARDS. The authors sought to investigate the effects of PEEP titrated by stress index on lung recruitment and protection after recruitment maneuver (RM) in pulmonary ARDS patients.

Materials and methods

Thirty patients with pulmonary ARDS were enrolled. After RM, PEEP was randomly set according to stress index, oxygenation, static pulmonary compliance (Cst), or lower inflection point (LIP) + 2 cmH₂O strategies. Recruitment volume, gas exchange, respiratory mechanics, and hemodynamic parameters were collected.

Results

PEEP titrated by stress index (15.1 ± 1.8 cmH₂O) was similar to the levels titrated by oxygenation (14.5 ± 2.9 cmH₂O), higher than that titrated by Cst (11.3 ± 2.5 cmH₂O) and LIP (12.9 ± 1.6 cmH₂O) (P < 0.05). Compared with baseline, PaO₂/FiO₂ and recruitment volume were significantly improved after PEEP titration with the four strategies (P < 0.05). PaO₂/FiO₂ and recruitment volume were similar when using PEEP titrated by stress index and oxygenation but higher than that titrated by Cst and LIP. Compared with baseline, lung compliance increased significantly when PEEP determined by Cst, but there was no difference of Cst in these four strategies. There was no influence of PEEP titration with the four strategies on hemodynamic parameters.

Conclusions

PEEP titration by stress index might be more beneficial for pulmonary ARDS patients after RM.     

A case of fluminant myocarditis with fetal pulmonary edema even after introduction of bi-ventricular assist devices

A 15-year-old man developed cardiopulmonary dysfunction 4 days after flu-like symptom, and was transfered to our hospital and diagnosed as a fulminant myocarditis (FM). Intraaortic ballon pumping (IABP) and percutaneous cardiopulmonary support (PCPS) were immediately initiated. However, cardiac function did not recover until 7 days after admission to the ICU, and bilateral ventricular assist devices (BiVAD) were introduced with extracorporeal membrane oxygenation (ECMO). Right ventricular assist device (RVAD) with ECMO was established by right atrial blood withdrawal and pulmonary arterial blood supply using centrifugal pump. After operation of BiVAD, to main LVAD flow, frequent blood-and-fluids volume loading and increase in RVAD flow were necessary due to postoperative bleeding and massive foamy sputum. However, even after hemostasis had been established, the pulmonary edema continued and it was difficult to maintain LVAD flow because of endless transudation from the lungs. Eventually, he developed MOF and passed away 9 days after the admission to ICU. As in cases of end-stage dilated cardiomyopathy, outflow of RVAD into the left atrium instead of the pulmonary artery was demonstrated effective in avoiding trans-pulmonary leakage, and outflow of RVAD into the left atrium may be beneficial to patients with FM who need BiVAD but suffered severe pulmonary edema.