Background

High oxygen levels may worsen cardiac arrest reperfusion injury. We determined the incidence of hyperoxia during and immediately after successful cardiopulmonary resuscitation and identified factors associated with intra-arrest cerebral oxygenation measured with near-infrared spectroscopy (NIRS).

Methods

A prospective observational study of out-of-hospital cardiac arrest patients treated by a physician-staffed helicopter unit. Collected data included intra-arrest brain regional oxygen saturation (rSO₂) with NIRS, invasive blood pressures, end-tidal CO₂ (etCO₂) and arterial blood gas samples. Moderate and severe hyperoxia were defined as arterial oxygen partial pressure (paO₂) 20.0−39.9 and ≥40 kPa, respectively. Intra-arrest factors correlated with the NIRS value, rSO_2, were assessed with the Spearman’s correlation test.

Results

Of 80 recruited patients, 73 (91%) patients had rSO₂ recorded during CPR, and 46 had an intra-arrest paO₂ analysed. ROSC was achieved in 28 patients, of whom 20 had paO₂ analysed. Moderate hyperoxia was seen in one patient during CPR and in four patients (20%, 95% CI 7−42%) after ROSC. None had severe hyperoxia during CPR, and one patient (5%, 95% 0–25%) immediately after ROSC. The rSO₂ during CPR was correlated with intra-arrest systolic (r = 0.28, p < 0.001) and diastolic blood pressure (p = 0.32, p<0.001) but not with paO₂ (r = 0.13, p = 0.41), paCO₂ (r = 0.18, p = 0.22) or etCO₂ (r = 0.008, p = 0.9).

Conclusion

Hyperoxia during or immediately after CPR is rare in patients treated by physician-staffed helicopter units. Cerebral oxygenation during CPR appears more dependent, albeit weakly, on hemodynamics than arterial oxygen concentration.

中文翻译：

---

心肺复苏过程中高氧的发生率及脑氧合相关因素

背景

高氧水平可能会加重心脏骤停再灌注损伤。我们确定了成功心肺复苏期间和之后的高氧发生率，并确定了用近红外光谱 (NIRS) 测量的与骤停脑氧合相关的因素。

方法

一项由医生配备直升机单位治疗的院外心脏骤停患者的前瞻性观察研究。收集的数据包括 NIRS 的脑内区域氧饱和度 (rSO ₂ )、有创血压、潮气末 CO ₂ (etCO ₂ ) 和动脉血气样本。中度和重度高氧分别定义为动脉氧分压 (paO ₂ ) 20.0-39.9 和≥40 kPa。用 Spearman 相关检验评估与NIRS 值 rSO _{2相关的逮捕内因素。}

结果

在招募的 80 名患者中，73 名 (91%) 患者在 CPR 期间记录了 rSO ₂，​​46 名患者进行了骤停期间 paO ₂分析。28 名患者实现了 ROSC，其中 20 名患者进行了 paO ₂分析。一名患者在 CPR 期间观察到中度高氧，在 ROSC 后观察到四名患者（20%，95% CI 7-42%）。在 CPR 期间没有人出现严重的高氧血症，1 名患者（5%，95% 0-25%）在 ROSC 后立即出现。CPR 期间的 rSO ₂与骤停时收缩压 (r = 0.28, p < 0.001) 和舒张压 (p = 0.32, p<0.001) 相关，但与 paO ₂ (r = 0.13, p = 0.41)、paCO 无关₂ (r = 0.18, p = 0.22) 或 etCO ₂ (r = 0.008, p = 0.9)。

结论

CPR 期间或之后立即出现高氧血症在由医生配备的直升机单位治疗的患者中很少见。CPR 期间的脑氧合似乎比动脉氧浓度更依赖于血流动力学，尽管较弱。