Electrical impedance tomography: ready for prime time?

Intensive Care Med (2006) 32:12901292DOI 10.1007/s00134-006-0253-z EDITORIALGerhard K. WolfJohn H. Arnold Electrical impedance tomography:

ready for prime time?Received: 24 May 2006Accepted: 24 May 2006Published online: 24 June 2006

Springer-Verlag 2006This editorial refers to the article available at: http://dx.doi.org/10.1007/s00134-006-00252-0G. K. Wolf J. H. Arnold ()Childrens Hospital Boston, Harvard Medical School,

Division of Critical Care Medicine, Department of Anesthesia,

Boston Mass., USAe-mail: [email protected].: [phone]Fax: [phone]Electrical impedance tomography (EIT) continues to

fascinate investigators as it is the only noninvasive technique that provides insight into the regional distribution of

ventilation. As investigations with computed tomography

(CT) have taught us, acute lung injury (ALI) and acute

respiratory distress syndrome (ARDS) are heterogeneous

diseases, and regional differences in compliance are

associated with distinct regional differences in opening

and closing pressures [1, 2, 3, 4]. While CT images

provide important information about alveolar collapse

and reversal of atelectasis, the technique is not easily

applied to routine management of patients with ALI [5].

The technology underlying EIT was first developed over

30 years ago, and a variety of EIT systems have been

used as research devices to investigate gastric emptying,

cerebral ischemia, breast cancer, and, relevant to this

discussion, lung tissue [6]. Recent investigations have

focused on the utility of EIT to detect regional imbalances

in ventilation in animals [7, 8, 9] and in patients with

ALI [10, 11].In Intensive Care Medicine Heinrich and coworkers [12] now report their investigation of the effect on

body and head position on lung ventilation in infants.

The authors describe the application of EIT to a group

of term and near-term infants. The patient population

did include several former preterm infants, but all were

classified as free of lung disease at the time of enrollment.

Ten spontaneously breathing, unsedated infants and ten

infants undergoing mechanical ventilation after various

surgical procedures but without lung disease were recruited. The cohort was studied in the supine and prone

positions and after positioning the head to the left, right,

and midline (supine only). The authors report significant

effects on the distribution of ventilation due to posture

(supine vs. prone) as well as to head position even during

positive pressure ventilation. They utilized a 16-electrode

EIT system to quantify imbalances in ventilation in the