Chan TC, Vilke GM, Michalewicz BA, Neuman T, Levy S, Kolkhorst F.
Does physical restraint impact metabolic oxygen consumption during exertion?
Acad Emerg Med May 2006;13 S46.
This is the abstract of a study presentation offered at the Annual Meeting of the Society for Academic Emergency Medicine, May 1821, 2006, in San Francisco. It was included in the special 2006 SAEM Annual Meeting Abstracts supplement, published as Acad Emerg Med Volume 13, Number 5_suppl_1 8, © 2006.
Because it is so short, I have placed the abstract's full text on this page. However! If you want to PRINT this abstract, print it from the PDF file of the 2006 SAEM Annual Meeting Abstracts supplement page containing it.
CLICK HERE to go to this abstract's PDF File.
CHAS' REVIEW follows the Abstract's full text.
Does Physical Restraint Impact Metabolic Oxygen Consumption during Exertion?
Theodore C Chan, Gary M Vilke, Betty A Michalewicz,
Tom Neuman, Susan Levy, and Fred Kolkhorst.
UC San Diego, San Diego, CA,
San Diego State University, San Diego, CA
Objectives: Combative patients often require physical restraint by emergency department (ED) and out-of-hospital personnel. We sought to determine metabolic demands and peak oxygen consumption (VO2peak) during maximal exertion in the prone restraint position compared with standard maximal treadmill testing. We hypothesized that restraint would reduce oxygen consumption because of limitations in physical movement.
Methods: 30 human subject volunteers completed a crossover, controlled experiment. Subjects performed two randomized trials, a standard maximal treadmill test (control) and maximal exertion while in a prone maximal restraint or hobble position (PMRP) at a university exercise physiology laboratory. To prevent fatigue bias, the trials were separated by at least 1 day. During PRMP, subjects were placed prone with their wrists handcuffed behind the back, the ankles secured to each other, and the wrists and ankles secured to each other by standard hobble strap. During the 60-second test, subjects were asked and encouraged to struggle and maximally exert themselves during which time VO2, respiratory rate (RR), and heart rate (HR) were measured. For the control, subjects performed a maximal exercise treadmill test using standard protocol. Data were compared with paired t-testing and 95% confidence intervals (95% CIs).
Results: VO2peak in the PRMP position (19.8 +/- 5.4 mL/kg/ min; CI 18.2-22.2) was only 39% of VO2peak from the control (50.2 +/- 7.8 mL/kg/min; CI 47.1-53.2) (p < 0.01). Also, peak HR was significantly lower in PMRP (160 +/- 19 beats/min; CI 156-176) compared with treadmill test (190 +/- 12 beats/min; CI 183-192) (p < 0.01); whereas there was no significant difference in RR (56 +/- 8 breaths/min [CI 52-59] for the PMRP trial vs 60 +/- 14 breaths/min [CI 54-65] for the treadmill trial) (p = 0.15).
Conclusions: In a study of human volunteer subjects, metabolic oxygen consumption in the restraint position was significantly lower when compared with standard maximal treadmill testing.
"30 human subject volunteers"
No information was provided about the health or body size screening that the study volunteers were subjected to prior to acceptance. Based upon previous studies designed and performed by Chan et al, it is more likely than not that the participating study subjects were entirely healthy and not overweight.
"During PRMP, subjects were placed prone with their wrists handcuffed behind the back, the ankles secured to each other, and the wrists and ankles secured to each other by standard hobble strap."
No EXERCISE was performed prior to placing the subjects in "PRMP." And, no WEIGHT was applied to the posterior torso of the study subjects while in "PRMP."
"During the 60-second test, subjects were asked and encouraged to struggle and maximally exert themselves..."
A "60-second" test?! Why so brief? When takedown and forceful-prone-restraint initiation is preceded by significant exertion, and significant exertion is continued against weight and force application in the "PRMP," a healthy, slender individual may enter respiratory arrest (retaining continued cardiac function) within 2 to 3 minutes of takedown and forceful-prone-restraint initiation. But, all the study subjects were entirely rested prior to being placed in a "PRMP" without any weight or force applied. Furthermore, the study subjects were free to roll to their side should they develop any serious difficulty breathing. Thus, it would have been entirely safe to perform the "test" for at least 2 to 3 minutes! A 60-second test is ludicrously brief.
No WEIGHT or RESISTANCE was provided for the study subjects to "struggle" against. Did the study creators standardize what kinds of "struggle" motions should be used by the subjects? Were the study subjects screaming during the "struggle"?
"For the control, subjects performed a maximal exercise treadmill test using standard protocol."
What is the duration of a "standard protocol" for a "maximal exercise treadmill test"? Had the treadmill duration employed by the study creators been only 60 seconds, one would anticipate them having said so. Since they did not specify the amount of time subjects spent on the treadmill, it could have been any amount of time!
"...there was no significant difference in RR (56 +/- 8 breaths/min [CI 52-59] for the PMRP trial vs 60 +/- 14 breaths/min [CI 54-65] for the treadmill trial)"...
A rapid respiratory rate (RR) is the "cure" to most of the factors that allow forceful-prone-restraint to kill people. It is only when a person is prevented from hyperventilating that restraint asphyxia occurs. Thus, only if the ability of the study subjects to hyperventilate was prevented would this study have honestly measured whether or not "Physical Restraint [Impacts] Metabolic Oxygen Consumption During Exertion."
THE BOTTOM LINE:
This is YET ANOTHER entirely unhelpful study designed and implemented by the Chan et al types. What is this the fourth or fifth entirely unhelpful study they've wasted hundreds of hours and thousands of dollars on? I've lost count.
As usual, the number of "real life" factors that accompany forceful-prone-restraint deaths that this study failed to include but safely could have included clearly indicates that the Chan et al types had absolutely no interest in honestly or realistically studying whether or not "Physical Restraint [Impacts] Metabolic Oxygen Consumption During Exertion."