The study describes the implementation of a prehospital treatment algorithm that included intravenous (IV) bolus (IVB) nitroglycerin (NTG) followed by maintenance infusion for the treatment of acute pulmonary edema (APE) in a single, high-volume Emergency Medical Services (EMS) system.

This is a retrospective chart review of patients who received IVB NTG for APE in a large EMS system in Minnesota and Wisconsin (USA). Inclusion criteria for treatment included a diagnosis of APE, systolic blood pressure ≥120mmHg, and oxygen saturation (SpO2) ≤93% following 800mcg of sublingual NTG. Patients received a 400mcg IVB of NTG, repeated every two minutes as needed, and subsequent infusion at 80mcg/min for transport times ≥10 minutes.

Forty-four patients were treated with IVB NTG. The median total bolus dose was 400mcg. Twenty patients were treated with NTG infusion following IVB NTG. The median infusion rate was 80mcg/min. For all patients, the initial median blood pressure was 191/113mmHg. Five minutes following IVB NTG, it was 160/94mmHg, and on arrival to the emergency department (ED) it was 152/90mmHg. Five minutes after the initial dose of IVB NTG, median SpO2 increased to 92% from an initial reading of 88% and was 94% at hospital arrival. One episode of transient hypotension occurred during EMS transport.

Patients treated with IVB NTG for APE had reduction in blood pressure and improvement in SpO2 compared to their original presentation. Prehospital treatment of APE with IVB appears to be feasible and safe. A randomized trial is needed to confirm these findings.

The esophageal detector device (EDD) recently has been found to assess endotracheal (ET) tube placement accurately. This study describes the reliability of the EDD in determining the position of the ET tube in clinical airway situations that are difficult.

This was a prospective, randomized, single-blinded, controlled laboratory investigation. Two airway managers (an emergency-medicine attending physician and a resident) determined ET-tube placement using the EDD in five swine in respiratory arrest. The ET tube was placed in the following clinical airway situations: 1) esophagus; 2) esophagus with 1 liter of air instilled; 3) trachea; 4) trachea with 5 ml/kg water instilled; and 5) right mainstem bronchus. Anatomic location of the tube was verified by thoracotomy of the left side of the chest.

There was 100% correlation between the resident and attending physician's use of the EDD. The EDD was 100% accurate in determining tube placement in the esophagus, in the esophagus with 1 liter of air instilled, in the trachea, and in the right mainstem bronchus. The airway managers were only 80% accurate in detecting tracheal intubations when fluid was present.

The EDD is an accurate and reliable device for detecting ET-tube placement in most clinical situations. Tube placement in fluid-filled trachea, lungs, or both, which occurs in pulmonary edema and drowning, may not be detected using this device.

The purposes of this study are to quantify the use of nitroglycerin (NTG) in prehospital care, to detect deviations from the Standing Medical Orders (SMO), to determin the effectiveness of its administration, and the incidence of clinically significant adverse reactions (hypotension, bradycardia).

Retrospective review of 7683 Advanced Life Support (ALS) telemetry, base-station contacts over a three month period (June, July, Auguest 1990) to identify all prehospital patient contacts in which NTG was utilized.

The Resource Hospital/Telemetry Base-Station a two community hospitals/Telemetry Base-Stations for the Chicago North EMS System.

There were 445 runs in which NTG was indicated as per SMO. Two hundred eighty-eight patients (64.7%) received NTG for appropriate indications as per SMO, 203 for ischemic chest pain (45.6%), 79 for pulmonary edema (17.7%), and six for both (1.3%). There were 157 (35.5%) runs in which NTG was indicated, but not administered. There were 22 patients who received NTG for indications that deviated from the SMO. Reassessment data concerning the subjective symptom was completed on 118 patients (40.9%), 92 (45.3%) patients with chest pain and 26 with dyspnea (32.9%). Following the administration of NTG, 21 patients (10.1%) with chest pain were unchanged, while 13 with dyspnea (15.3%) improved, 13 patients (15.3%) were unchanged, and none worsened. In 121 patients, the systolic blood pressure (SBP) decreased, while 24 were unchanged (5.4%), and 28 had an increase (6.3%). The mean initial value SBP was 176±44 mmHg and the repeat mean SBP was 164±41 mmHg with a mean decrease of 12±22 mmHg. The diastolic blood pressure (DBP) decreased in 87 patients, was unchanged in 53 (11.9%), and increased in 33 (7.4%). The initial mean DBP was 97±24 mmHg, the repeat mean DBP was 92±23 mmHg, a mean decrease of 5±15 mmHg. Only one patient became hypotensive with the administration of NTG and was successfully resusticated with a fluid bolus of 300 ml normal saline.

In this EMS system, NTG is under-utilized based on the indications delineated by this system's SMOs. Reassessment is documented infrequently, but when completed, clinically significant adverse reactions are rare. Since the incidence of hypotension and bradycardia are rare, the inability to establish an IV line should not preclude the administration of NTG.