Decay in chest compression quality due to fatigue is rare during prolonged advanced life support in a manikin model

Abstract

Background: The aim of this study was to measure chest compression decay during simulated advanced life support (ALS) in a cardiac arrest manikin model.

Methods: 19 paramedic teams, each consisting of three paramedics, performed ALS for 12 minutes with the same paramedic providing all chest compressions. The patient was a resuscitation manikin found in ventricular fibrillation (VF). The first shock terminated the VF and the patient remained in pulseless electrical activity (PEA) throughout the scenario. Average chest compression depth and rate was measured each minute for 12 minutes and divided into three groups based on chest compression quality; good (compression depth ≥ 40 mm, compression rate 100-120/minute for each minute of CPR), bad (initial compression depth < 40 mm, initial compression rate < 100 or > 120/minute) or decay (change from good to bad during the 12 minutes). Changes in no-flow ratio (NFR, defined as the time without chest compressions divided by the total time of the ALS scenario) over time was also measured.

Results: Based on compression depth, 5 (26%), 9 (47%) and 5 (26%) were good, bad and with decay, respectively. Only one paramedic experienced decay within the first two minutes. Based on compression rate, 6 (32%), 6 (32%) and 7 (37%) were good, bad and with decay, respectively. NFR was 22% in both the 1-3 and 4-6 minute periods, respectively, but decreased to 14% in the 7-9 minute period (P = 0.002) and to 10% in the 10-12 minute period (P < 0.001).

Conclusions: In this simulated cardiac arrest manikin study, only half of the providers achieved guideline recommended compression depth during prolonged ALS. Large inter-individual differences in chest compression quality were already present from the initiation of CPR. Chest compression decay and thereby fatigue within the first two minutes was rare.

Figure 1

Distribution of chest compression depth. Boxplot showing the distribution of chest compression depths for each minute during twelve minutes of advanced life support on a manikin (n = 19). Centre line indicates median value, boxes indicate interquartile range and straight lines indicate maximum and minimum values. The circle denotes an outlier.

Figure 2

Development of chest compression depth. Development of chest compression depth for each of 19 resuscitation attempts, the good are illustrated in A (5/19, 26%), the bad in B (9/19, 47%) and those with decay in C (5/19, 26%). Arrows indicate when each paramedic first developed decay in chest compression depth to < 40 mm. See text for definition of groups.

Figure 3

Development of chest compression rate. Development of chest compression rate for each of 19 resuscitation attempts, the good are illustrated in A (6/19, 32%), the bad in B (6/19, 32%) and those with decay in C (7/19, 37%). Arrows indicate when each paramedic developed decay in chest compression rate to < 100 or > 120 per minute. See text for definition of groups.

Figure 4

Development of no-flow ratio. Development of no-flow ratio measured in three minute periods for all 19 resuscitation attempts.