Mechanical ventilation in conjunction with the intra-aortic balloon pump improves the outcome of patients in profound cardiogenic shock

Objective: To examine the effects of mechanical ventilation with positive end-expiratory pressure (PEEP), in conjunction with the intra-aortic balloon pump (IABP), on the outcome of patients in profound cardiogenic shock. Patients: Twenty-eight consecutive patients presenting with myocardial infarction complicated by cardiogenic shock refractory to medical therapy, including dobutamine, dopamine and fluid administration. Eighteen patients were assisted by the IABP alone (IABP group), and ten patients by the IABP plus controlled mechanical ventilation with PEEP set at 10 cmH₂O (IABP + CMV group). Results: Weaning from mechanical assistance was accomplished in 8 out of 18 patients in the IABP group versus 9 out of 10 patients in the IABP + CMV group (p = 0.04). Ultimately, 5 of 18 patients in the IABP group were discharged from the hospital versus 8 of 10 patients in the IABP + CMV group (p = 0.01). Conclusion: Mechanical ventilation with PEEP at 10 cmH₂O supplements the IABP and may improve the survival rates of patients suffering from cardiogenic shock. Received: 12 November 1998 Final revision received: 28 March 1999 Accepted: 4 May 1999     

联合应用机械通气和主动脉球囊反搏治疗心源性休克

目的观察联合应用机械通气和主动脉球囊反搏(IABP)治疗急性心肌梗死(AMI)合并心源性休克的疗效,探讨与死亡相关的危险因素。方法回顾分析解放军总医院心内科监护室2003～2005年联合应用机械通气和IABP治疗的AMI后心源性休克病例临床资料,观察疗效并对影响患者预后的相关因素进行回归分析。结果联合应用机械通气和IABP治疗AMI后心源性休克患者27例,康复出院7例,院内死亡20例,死亡率74%。多因素分析表明,发生急性肾衰竭是增加院内死亡风险的独立预测因素。结论AMI合并心源性休克联合应用机械通气和IABP治疗死亡率仍然很高,急性肾衰竭是增加死亡风险的独立预测因素。     

A blinded,randomized, controlled trial of three doses of high-dose insulin in poison-induced cardiogenic shock

Background. High dose insulin (HDI) has proven superior to glucagon and catecholamines in the treatment of poison-induced cardiogenic shock (PICS) in previous animal studies. Standard recommendations for dosing of insulin vary and the optimal dose of HDI in PICS has not been established. Our hypothesis was a dose of 10 U/kg/hr of HDI would be superior to 1 U/kg/hr with cardiac output (CO) as our primary outcome measure in pigs with propranolol-induced PICS. Methods. This was a blinded, prospective, randomized trial with 4 arms consisting of 4 pigs in each arm. The arms were as follows: placebo (P), 1 U/kg/hr (HDI-1), 5 U/kg/hr (HDI-5), and 10 U/kg/hr (HDI-10). Cardiogenic shock was induced with a bolus of 0.5 mg/kg of propranolol followed by an infusion of 0.25 mg/kg/min until the point of toxicity, defined as 0.75 x (HR x MAP) was reached. At this point the propranolol infusion was decreased to 0.125 mg/kg/min and a 20 mL/kg bolus of normal saline (NS) was administered. The protocol was continued for 6 hours or until the animals died. Results. 2 pigs died in the P arm, 1 pig died each in the HDI-1 and HDI-5 arms, and all pigs lived in the HDI-10 arm. There was a statistically significant difference in dose by time interaction on CO of 1.13 L/min over the 6 hr study period (p = < 0.001). There was also a statistically significant difference in dose by time interaction on MAP, HR, and systemic vascular resistance (SVR). No statistically significant difference was found between any of the arms regarding glucose utilization. Conclusion. HDI was statistically and clinically significantly superior to placebo in this propranolol model of PICS. Furthermore a dose response over time was found where CO increased corresponding to increases in doses of HDI.     

Auto-PEEP and dynamic hyperinflation in COPD patients during controlled mechanical ventilation and high frequency jet ventilation

We investigated the levels of auto-PEEP and dynamic hyperinflation during high frequency jet ventilation (HFJV) and controlled mechanical ventilation (CMV) in six patients with chronic obstructive pulmonary disease within the first 36h of acute exacerbation. The comparative evaluation was performed at similar conditions of gas exchange in HFJV and CMV: PaO₂ 77.6±11 mmHg vs 80.8±12 mmHg; PaCO₂ 46.8±2.5 mmHg vs 47±2.8 mmHg; pH 7.38 vs 7.38. In this situation, the values of auto-PEEP and dynamic hyperinflation, expressed as Δ over the apneic functional residual capacity (FRC) did not differ: (auto-PEEP_HFJV 8.9±3.8 cmH₂O; auto-PEEP_CMV 8.8±4.7 cmH₂O; ΔFRC_HFJV 0.56±0.191; ΔFRC_CMV 0.54±0.2l). This result suggests that, with a suitable machine setting and similar gas exchanges, HFJV produces the same level of auto-PEEP and dynamic hyperinflation as CMV in patients with chronic obstructive pulmonary disease.