Prehospital Intubations Are Associated with Elevated Endotracheal Tube Cuff Pressures: A Cross-Sectional Study Characterizing ETT Cuff Pressures at a Tertiary Care Emergency Department.

INTRODUCTION: Emergency Medical Services (EMS) providers are trained to place endotracheal tubes (ETTs) in the prehospital setting when indicated. Endotracheal tube cuffs are traditionally inflated with 10cc of air to provide adequate seal against the tracheal lumen. There is literature suggesting that many ETTs are inflated well beyond the accepted safe pressures of 20-30cmH2O, leading to potential complications including ischemia, necrosis, scarring, and stenosis of the tracheal wall. Currently, EMS providers do not routinely check ETT cuff pressures. It was hypothesized that the average ETT cuff pressure of patients arriving at the study site who were intubated by EMS exceeds the safe pressure range of 20-30cmH2O. OBJECTIVES: While ETT cuff inflation is necessary to close the respiratory system, thus preventing air leaks and aspiration, there is evidence to suggest that over-inflated ETT cuffs can cause long-term complications. The purpose of this study is to characterize the cuff pressures of ETTs placed by EMS providers. METHODS: This project was a single center, prospective observational study. Endotracheal tube cuff pressures were measured and recorded for adult patients intubated by EMS providers prior to arrival at a large, urban, tertiary care center over a nine-month period. All data were collected by respiratory therapists utilizing a cuff pressure measurement device which had a detectable range of 0-100cmH2O and was designed as a syringe. Results including basic patient demographics, cuff pressure, tube size, and EMS service were recorded. RESULTS: In total, 45 measurements from six EMS services were included with ETT sizes ranging from 6.5-8.0mm. Mean patient age was 52.2 years (67.7% male). Mean cuff pressure was 81.8cmH2O with a range of 15 to 100 and a median of 100. The mode was 100cmH2O; 40 out of 45 (88.9%) cuff pressures were above 30cmH2O. Linear regression showed no correlation between age and ETT cuff pressure or between ETT size and cuff pressure. Two-tailed T tests did not show a significant difference in the mean cuff pressure between female versus male patients. CONCLUSION: An overwhelming majority of prehospital intubations are associated with elevated cuff pressures, and cuff pressure monitoring education is indicated to address this phenomenon.

A Comparison of Non-Invasive Blood Pressure Measurement Strategies with Intra-Arterial Measurement.

INTRODUCTION: It is difficult to obtain an accurate blood pressure (BP) measurement, especially in the prehospital environment. It is not known fully how various BP measurement techniques differ from one another. STUDY OBJECTIVE: The study hypothesized that there are differences in the accuracy of various non-invasive blood pressure (NIBP) measurement strategies as compared to the gold standard of intra-arterial (IA) measurement. METHODS: The study enrolled adult intensive care unit (ICU) patients with radial IA catheters placed to measure radial intra-arterial blood pressure (RIBP) as a part of their standard care at a large, urban, tertiary-care Level I trauma center. Systolic blood pressure (SBP) was taken by three different NIBP techniques (oscillometric, auscultated, and palpated) and compared to RIBP measurements. Data were analyzed using the paired t-test with dependent samples to detect differences between RIBP measurements and each NIBP method. The primary outcome was the difference in RIBP and NIBP measurement. There was also a predetermined subgroup analysis based on gender, body mass index (BMI), primary diagnosis requiring IA line placement, and current vasoactive medication use. RESULTS: Forty-four patients were enrolled to detect a predetermined clinically significant difference of 5mmHg in SBP. The patient population was 63.6% male and 36.4% female with an average age of 58.4 years old. The most common primary diagnoses were septic shock (47.7%), stroke (13.6%), and increased intracranial pressure (ICP; 13.6%). Most patients were receiving some form of sedation (63.4%), while 50.0% were receiving vasopressor medication and 31.8% were receiving anti-hypertensive medication. When compared to RIBP values, only the palpated SBP values had a clinically significant difference (9.88mmHg less than RIBP; P < .001). When compared to RIBP, the oscillometric and auscultated SBP readings showed statistically but not clinically significant lower values. The palpated method also showed a clinically significant lower SBP reading than the oscillometric method (5.48mmHg; P < .001) and the auscultated method (5.06mmHg; P < .001). There was no significant difference between the oscillometric and auscultated methods (0.42mmHg; P = .73). CONCLUSION: Overall, NIBPs significantly under-estimated RIBP measurements. Palpated BP measurements were consistently lower than RIBP, which was statistically and clinically significant. These results raise concern about the accuracy of palpated BP and its pervasive use in prehospital care. The data also suggested that auscultated and oscillometric BP may provide similar measurements.