Noninvasive Monitoring in the Intensive Care Unit

There has been considerable development in the field of noninvasive hemodynamic monitoring in recent years. Multiple devices have been proposed to assess blood pressure, cardiac output, and tissue perfusion. All have their own advantages and disadvantages and selection should be based on individual patient requirements and disease severity and adjusted according to ongoing patient evolution.

The Combined Use of Cardiac Output and Intracranial Pressure Monitoring to Maintain Optimal Cerebral Perfusion Pressure and Minimize Complications for Severe Traumatic Brain Injury

Objective

To show the effect of dual monitoring including cardiac output (CO) and intracranial pressure (ICP) monitoring for severe traumatic brain injury (TBI) patiens. We hypothesized that meticulous treatment using dual monitoring is effective to sustain maintain minimal intensive care unit (ICU) complications and maintain optimal ICP and cerebral perfusion pressure (CPP) for severe TBI patiens.

Methods

We included severe TBI, below Glasgow Coma Scale (GCS) 8 and head abbreviation injury scale (AIS) >4 and performed decompressive craniectomy at trauma ICU of our hospital. We collected the demographic data, head AIS, injury severity score (ISS), initial GCS, ICU stay, sedation duration, fluid therapy related complications, Glasgow Outcome Scale (GOS) at 3 months and variable parameters of ICP and CO monitor.

Results

Thirty patients with severe TBI were initially selected. Thirteen patients were excluded because 10 patients had fixed pupillary reflexes and 3 patients had uncontrolled ICP due to severe brain edema. Overall 17 patients had head AIS 5 except 2 patients and 10 patients (58.8%) had multiple traumas as mean ISS 29.1. Overall complication rate of the patients was 64.7%. Among the parameters of CO monitoring, high stroke volume variation is associated with fluid therapy related complications (p=0.043) and low cardiac contractibility is associated with these complications (p=0.009) statistically.

Conclusion

Combined use of CO and ICP monitors in severe TBI patients who could be necessary to decompressive craniectomy and postoperative sedation is good alternative methods to maintain an adequate ICP and CPP and reduce fluid therapy related complications during postoperative ICU care.

Applications of minimally invasive cardiac output monitors

Because of the increasing age of the population, critical care and emergency medicine physicians have seen an increased number of critically ill patients over the last decade. Moreover, the trend of hospital closures in the United States t imposes a burden of increased efficiency. Hence, the identification of devices that facilitate accurate but rapid assessments of hemodynamic parameters without the added burden of invasiveness becomes tantamount. The purpose of this review is to understand the applications and limitations of these new technologies.

Cardiac output monitoring devices: an analytic review

To evaluate cardiac output (CO), both invasive and semi-invasive monitors are used in critical care medicine. The pulmonary artery catheter is an invasive tool to assess CO with the major criticism that the level of its invasiveness is not supported by an improvement in patients' outcomes. The interest in a lesser invasive techniques is high. Therefore, alternative techniques have been developed recently, and are used frequently in critical care medicine. Cardiac output can be monitored continuously by different devices that analyze the stroke volume and CO. The purpose of this review is to understand these new technologies and their applications and limitations.

Continuous cardiac output and near-infrared spectroscopy monitoring to assist in management of symptomatic cerebral vasospasm after subarachnoid hemorrhage

BACKGROUND

Hemodynamic augmentation by increasing cardiac output with dobutamine (DOB) is believed to be a useful method of elevating decreased cerebral blood flow in the territory affected by vasospasm following aneurysmal subarachnoid hemorrhage (SAH). We described the clinical utility of uncalibrated radial artery-based pulse contour cardiac output (APCO) and near-infrared spectroscopy regional cerebral oxygen saturation (rSO(2)) monitoring for reversing vasospasm symptoms with DOB-induced hyperdynamic therapy.

METHODS

Seven consecutive patients who underwent surgical clipping within 24 h of SAH onset and subsequently developed delayed ischemic neurological deficits attributable to vasospasm were investigated. They were treated with DOB administered at a dose of 3 μg/kg/min and then increased in 3 μg/kg/min increments until resolution of the symptoms. Continuous APCO and rSO(2) measurements in conjunction with the assessment of clinical courses and outcomes were performed.

RESULTS

In spasm-affected territories, decreased and/or fluctuating rSO(2) was detected at baseline compared with recordings in other brain regions. Patients who exhibited rapid elevation of APCO in response to an incremental dose of DOB had subsequent uptake and stabilization of rSO(2) followed by improvement of vasospasm-related clinical symptoms with a maximal dose of DOB, resulted in favorable functional outcomes thereafter. A fairly strong relationship was found between peak APCO slope and rSO(2) elevation, with a significantly high area under the receiver operating characteristic curve predicting neurological improvement with DOB treatment.

CONCLUSIONS

Our clinical experience indicates that integrative monitoring with APCO and rSO(2) may provide continuous, real-time, and clinically relevant information on the effectiveness of medical treatment of distal vessel vasospasm.

Effects of on-pump and off-pump coronary artery bypass grafting on left ventricular relaxation and compliance: a comprehensive perioperative echocardiography study

AIMS

The short-term effect of coronary artery bypass grafting (CABG) on diastolic function is only moderately investigated. Furthermore, it remains unknown whether avoidance of cardioplegic arrest by an off-pump CABG procedure has advantages over on-pump procedure regarding diastolic relaxation and compliance. We investigated whether components of diastolic function would be improved the day after CABG depending on the type of the surgical procedure.

METHODS AND RESULTS

Spontaneously breathing on-pump (n = 20) and off-pump CABG (n = 12) patients underwent a comprehensive transthoracic echocardiography examination the day before and the day after elective CABG, including transmitral and pulmonary vein flow parameters, colour M-mode flow propagation velocity (Vp) and tissue Doppler assessment of the average mitral annulus diastolic velocity (Em). Isovolumic relaxation and E-wave deceleration time were corrected for heart rate (IVRTcHR and DTcHR). Left ventricular (LV) relaxation time (τ) and LV operating stiffness (LVOS) were calculated. Overall and independent from operation type and preload, CABG decreased IVRTcHR (107 ± 20 vs. 93 ± 15 ms) (P < 0.01) and τ (54 ± 10 vs. 45 ± 10 ms) (P < 0.01), increased Vp (49 ± 22 vs. 75 ± 37 cm/s) (P < 0.01), and increased Em (6.6 ± 2.0 vs. 7.3 ± 1.3 cm/s, P = 0.06), indicating improved relaxation. LVOS increased (0.13 ± 0.06 vs. 0.22 ± 0.05 mmHg/mL) (P < 0.01), compatible with an impaired compliance. A similar improvement in relaxation and impairment in compliance were observed in both groups.

CONCLUSION

Myocardial relaxation improved the day after CABG irrespective of the use of cardiopulmonary bypass with cardioplegic arrest. Impairment in compliance could not be prevented by the avoidance of cardioplegia.