CHAPTER 63: Field Diagnostics

INTRODUCTION

Diagnostic evaluation of patients in the field continues to see new advancements. In addition to performance of a high-quality history and examination, EMS physicians should be able to perform a number of diagnostic procedures in the field. The procedures detailed below are core EMS physician skills; however, there are a number of equipment specific diagnostic maneuvers that are beyond the scope of this chapter due to variability in equipment manufactures. In addition to the diagnostics covered in this text EMS physicians should be familiar with use of the monitor functions of their agencies' monitor/defibrillators, thermometers, and any point-of-care testing devices the agency cares: blood glucometers, lactate meters, and minianalyzers.

FIELD DIAGNOSTIC PROCEDURES

Below is a list of field diagnostic techniques covered in this chapter.

• Performing a prehospital 12-lead ECG

• Waveform capnography

• Prehospital ultrasound

• Compartment pressure monitoring

12-LEAD ELECTROCARDIOGRAM

Indications

• Chest pain

• Back, neck, jaw, or arm pain without chest pain

• Upper abdominal pain or reflux symptoms

• Syncope (or near syncope)

• Palpitations or unexplained tachycardia

• Dyspnea of uncertain origin

• Diaphoresis of uncertain origin

• Anxiety (+/− sense of impending doom)

• Suspected electrolyte abnormalities (DKA, CRF, adrenal insufficiency)

• Found down for unknown period

• Crush injuries and compartment syndrome

• Environmental injury (hypothermia, hyperthermia, electrical injury, dysbarism, submersion/postdrowning)

• Generalized weakness

Essential Equipment

• Monitor/defibrillator with 12-lead capability

Technique

• Proper placement of the leads is important to avoid incorrect diagnosis and negative changes on the ECG (Figure 63-1).

• Place V1 electrode at the fourth intercostal space to the right of the sternum.

• Place V2 electrode at the fourth intercostal space to the left of the sternum.

• Place V3 electrode in the middle of V2 and V4.

• Place V4 electrode at the fifth intercostal space at the midclavicular line.

• Place V5 electrode at the anterior axillary line at the same level of V4.

• Place V6 electrode at the midaxillary line at the same level as V4 and V5.

• Place RL electrode below the torso but above the ankle.

• Place LL electrode below the torso but above the ankle.

• Place the RA electrode below the right shoulder and above the right elbow.

• Place the LA electrode below the left shoulder and above the left elbow.

Interpretation

• A thorough understanding of the electrophysiology of the heart is important for interpretation of the ECG. Recognition of basic and lethal rhythms is essential. Diagnosis directs therapy which in certain cases is lifesaving. The scope of this book does not lend itself to teach ECG readings and interpretation. EMS physicians must have a mastery of basic 12-lead interpretation inclusive of rhythms identification and evaluation of ischemia, MI, conduction delays, and signs of toxicological findings.

WAVEFORM CAPNOGRAPHY

Indications

• Capnography is a ...