Continuous noninvasive monitoring of cardiac performance and tissue perfusion in pediatric trauma patients

Current state of noninvasive, continuous monitoring modalities in pediatric anesthesiology

PURPOSE OF REVIEW

The last decades, anesthesia has become safer, partly due to developments in monitoring. Advanced monitoring of children under anesthesia is challenging, due to lack of evidence, validity and size constraints. Most measured parameters are proxies for end organ function, in which an anesthesiologist is actually interested. Ideally, monitoring should be continuous, noninvasive and accurate. This present review summarizes the current literature on noninvasive monitoring in noncardiac pediatric anesthesia.

RECENT FINDINGS

For cardiac output (CO) monitoring, bolus thermodilution is still considered the gold standard. New noninvasive techniques based on bioimpedance and pulse contour analysis are promising, but require more refining in accuracy of CO values in children. Near-infrared spectroscopy is most commonly used in cardiac surgery despite there being no consensus on safety margins. Its place in noncardiac anesthesia has yet to be determined. Transcutaneous measurements of blood gases are used mainly in the neonatal intensive care unit, and is finding its way to the pediatric operation theatre. Especially CO2 measurements are accurate and useful.

SUMMARY

New techniques are available to assess a child's hemodynamic and respiratory status while under anesthesia. These new monitors can be used as complementary tools together with standard monitoring in children, to further improve perioperative safety.

Non-invasive cardiac output monitoring device "ICON" in trauma patients: a feasibility study

PURPOSE

Assessment of hemodynamics is crucial for the evaluation of major trauma patients. Cardiac output (CO) monitoring provides additional information and may improve volume resuscitation. The goal of this prospective pilot study was to evaluate the feasibility of a new non-invasive CO monitoring (NICOM) device in the emergency department (ED).

METHODS

Single-center prospective observational pilot study including 20 trauma patients admitted to a level 1 trauma center. CO was continuously monitored for 60 min after ED admission using the new NICOM device ICON^®. This device measures changes of the thoracic bioimpedance to calculate CO. Conventional vital signs were recorded simultaneously. Feasibility, safety, reliability, user-friendliness, and impact of the device on standard ED procedures were assessed.

RESULTS

Thirteen (65%) patients were male, median age was 57.5 (IQR 25), and median ISS was 10.5 (IQR 14.8). Median CO over time was 9.8 l/min (IQR 4.6). No adverse effects were recorded. The device proved to be user-friendly with no negative impact on routine ED care. In four patients, detachment of electrodes was observed, and in four patients, the CO recording was temporary discontinued. Short-term changes of the CO were observed 44 times after the placement of electrodes and during patient transfers.

CONCLUSIONS

Non-invasive CO monitoring proved to be feasible and safe for the initial hemodynamic evaluation of trauma patients. Problems with the NICOM device were detachment of electrodes and temporary signal loss. Due to the small sample size and relatively low injury burden of the patients included in this study, further prospective investigation is warranted.

Non-invasive hemodynamic monitoring in trauma patients

BACKGROUND

The assessment of hemodynamic status is a crucial task in the initial evaluation of trauma patients. However, blood pressure and heart rate are often misleading, as multiple variables may impact these conventional parameters. More reliable methods such as pulmonary artery thermodilution for cardiac output measuring would be necessary, but its applicability in the Emergency Department is questionable due to their invasive nature. Non-invasive cardiac output monitoring devices may be a feasible alternative.

METHODS

A systematic literature review was conducted. Only studies that explicitly investigated non-invasive hemodynamic monitoring devices in trauma patients were considered.

RESULTS

A total of 7 studies were identified as suitable and were included into this review. These studies evaluated in a total of 1,197 trauma patients the accuracy of non-invasive hemodynamic monitoring devices by comparing measurements to pulmonary artery thermodilution, which is the gold standard for cardiac output measuring. The correlation coefficients r between the two methods ranged from 0.79 to 0.92. Bias and precision analysis ranged from -0.02 +/- 0.78 l/min/m(2) to -0.14 +/- 0.73 l/min/m(2). Additionally, data on practicality, limitations and clinical impact of the devices were collected.

CONCLUSION

The accuracy of non-invasive cardiac output monitoring devices in trauma patients is broadly satisfactory. As the devices can be applied very early in the shock room or even preclinically, hemodynamic shock may be recognized much earlier and therapeutic interventions could be applied more rapidly and more adequately. The devices can be used in the daily routine of a busy ED, as they are non-invasive and easy to master.

Clinical practice parameters for hemodynamic support of pediatric and neonatal septic shock: 2007 update from the American College of Critical Care Medicine

BACKGROUND

The Institute of Medicine calls for the use of clinical guidelines and practice parameters to promote "best practices" and to improve patient outcomes.

OBJECTIVE

2007 update of the 2002 American College of Critical Care Medicine Clinical Guidelines for Hemodynamic Support of Neonates and Children with Septic Shock.

PARTICIPANTS

Society of Critical Care Medicine members with special interest in neonatal and pediatric septic shock were identified from general solicitation at the Society of Critical Care Medicine Educational and Scientific Symposia (2001-2006).

METHODS

The Pubmed/MEDLINE literature database (1966-2006) was searched using the keywords and phrases: sepsis, septicemia, septic shock, endotoxemia, persistent pulmonary hypertension, nitric oxide, extracorporeal membrane oxygenation (ECMO), and American College of Critical Care Medicine guidelines. Best practice centers that reported best outcomes were identified and their practices examined as models of care. Using a modified Delphi method, 30 experts graded new literature. Over 30 additional experts then reviewed the updated recommendations. The document was subsequently modified until there was greater than 90% expert consensus.

RESULTS

The 2002 guidelines were widely disseminated, translated into Spanish and Portuguese, and incorporated into Society of Critical Care Medicine and AHA sanctioned recommendations. Centers that implemented the 2002 guidelines reported best practice outcomes (hospital mortality 1%-3% in previously healthy, and 7%-10% in chronically ill children). Early use of 2002 guidelines was associated with improved outcome in the community hospital emergency department (number needed to treat = 3.3) and tertiary pediatric intensive care setting (number needed to treat = 3.6); every hour that went by without guideline adherence was associated with a 1.4-fold increased mortality risk. The updated 2007 guidelines continue to recognize an increased likelihood that children with septic shock, compared with adults, require 1) proportionally larger quantities of fluid, 2) inotrope and vasodilator therapies, 3) hydrocortisone for absolute adrenal insufficiency, and 4) ECMO for refractory shock. The major new recommendation in the 2007 update is earlier use of inotrope support through peripheral access until central access is attained.

CONCLUSION

The 2007 update continues to emphasize early use of age-specific therapies to attain time-sensitive goals, specifically recommending 1) first hour fluid resuscitation and inotrope therapy directed to goals of threshold heart rates, normal blood pressure, and capillary refill 70% and cardiac index 3.3-6.0 L/min/m.

Continuous, non-invasive techniques to determine cardiac output in children after cardiac surgery: evaluation of transesophageal Doppler and electric velocimetry

BACKGROUND

Continuous and non-invasive measurement of cardiac output (CO) may contribute helpful information to the care and treatment of the critically ill pediatric patient. Different methods are available but their clinical verification is still a major problem.

AIM

Comparison of reliability and safety of two continuous non-invasive methods with transthoracic echocardiography (TTE) for CO measurement: electric velocimetry technique (EV, Aesculon) and transesophageal Doppler (TED, CardioQP). METHODS/MATERIAL: In 26 infants and children who had undergone corrective cardiac surgery at a median age of 3.5 (1-17) years CO and stroke volume (SV) were obtained by EV, TED and TTE. Each patient had five measurements on the first day after surgery, during mechanical ventilation and sedation.

RESULTS

Values for CO and SV from TED and EV correlated well with those of TTE (r = 0.85 and r = 0.88), but mean values were significantly lower than the values of TTE for TED (P = 0.02) and EV (P = 0.001). According to Bland-Altman analysis, bias was 0.36 l/min with a precision of 1.67 l/min for TED vs. TTE and 0.87 l/min (bias) with a precision of 3.26 l/min for EV vs. TTE. No severe adverse events were observed and the handling of both systems was easy in the sedated child.

CONCLUSIONS

In pediatric patients non-invasive measurement of CO and SV with TED and EV is useful for continuous monitoring after heart surgery. Both new methods seem to underestimate cardiac output in terms of absolute values. However, TED shows tolerable bias and precision and may be helpful for continuous CO monitoring in a deeply sedated and ventilated pediatric patient, e.g. in the operating room or intensive care unit.