The accuracy of PiCCO® measurements in hypothermic post-cardiac arrest patients

Influence of injection rates of calibrating standard solution on monitoring pulse indicator continuous cardiac output

OBJECTIVE

This study aimed to investigate the influence of injection rates of calibrating standard solution on monitoring pulse indicator continuous cardiac output (PICCO, made in Germany), and thereby to provide significant references for clinical practice.

METHODS

A total of 108 critical patients in stroke intensive care unit were identified. All these participants received transesophageal cardiac color Doppler ultrasound, and within 15 min PICCO equipment was utilized to monitor the relevant parameters, by means of 0 °C calibrating standard solution, and the injection speeds were 2-4, 5-7, and 8-10 s. Besides, the monitoring indicators were as follows, cardiac index, global ejection fraction, global end diastolic volume index. The potential correlations were evaluated between PICCO and transesophageal cardiac color Doppler ultrasound.

RESULTS

All the data was available, and the monitored parameters of PICOO at 2-4, 5-7, and 8-10 s were positively correlated with the parameters obtained from transesophageal cardiac color Doppler ultrasound (P < 0.05). Specially, it is worth emphasizing that the best correlation between them could be provided when the injection rate was 2-4 s.

CONCLUSION

When the injection rate at 2-4 s, the parameters obtained by PICOO were much closer to that of transesophageal cardiac color Doppler ultrasound. Furthermore, the parameters of PICOO obtained at 2-4 s could better reflect cardiac function of patients.

Induced Hypothermia Does Not Harm Hemodynamics after Polytrauma: A Porcine Model

BACKGROUND

The deterioration of hemodynamics instantly endangers the patients' life after polytrauma. As accidental hypothermia frequently occurs in polytrauma, therapeutic hypothermia still displays an ambivalent role as the impact on the cardiopulmonary function is not yet fully understood.

METHODS

We have previously established a porcine polytrauma model including blunt chest trauma, penetrating abdominal trauma, and hemorrhagic shock. Therapeutic hypothermia (34°C) was induced for 3 hours. We documented cardiovascular parameters and basic respiratory parameters. Pigs were euthanized after 15.5 hours.

RESULTS

Our polytrauma porcine model displayed sufficient trauma impact. Resuscitation showed adequate restoration of hemodynamics. Induced hypothermia had neither harmful nor major positive effects on the animals' hemodynamics. Though heart rate significantly decreased and mixed venous oxygen saturation significantly increased during therapeutic hypothermia. Mean arterial blood pressure, central venous pressure, pulmonary arterial pressure, and wedge pressure showed no significant differences comparing normothermic trauma and hypothermic trauma pigs during hypothermia.

CONCLUSIONS

Induced hypothermia after polytrauma is feasible. No major harmful effects on hemodynamics were observed. Therapeutic hypothermia revealed hints for tissue protective impact. But the chosen length for therapeutic hypothermia was too short. Nevertheless, therapeutic hypothermia might be a useful tool for intensive care after polytrauma. Future studies should extend therapeutic hypothermia.

Arterial waveform analysis

The bedside measurement of continuous arterial pressure values from waveform analysis has been routinely available via indwelling arterial catheterization for >50 years. Invasive blood pressure monitoring has been utilized in critically ill patients, in both the operating room and critical care units, to facilitate rapid diagnoses of cardiovascular insufficiency and monitor response to treatments aimed at correcting abnormalities before the consequences of either hypo- or hypertension are seen. Minimally invasive techniques to estimate cardiac output (CO) have gained increased appeal. This has led to the increased interest in arterial waveform analysis to provide this important information, as it is measured continuously in many operating rooms and intensive care units. Arterial waveform analysis also allows for the calculation of many so-called derived parameters intrinsically created by this pulse pressure profile. These include estimates of left ventricular stroke volume (SV), CO, vascular resistance, and during positive-pressure breathing, SV variation, and pulse pressure variation. This article focuses on the principles of arterial waveform analysis and their determinants, components of the arterial system, and arterial pulse contour. It will also address the advantage of measuring real-time CO by the arterial waveform and the benefits to measuring SV variation. Arterial waveform analysis has gained a large interest in the overall assessment and management of the critically ill and those at a risk of hemodynamic deterioration.