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Research Christmas 2018: Look Before You Leap

Parachute use to prevent death and major trauma when jumping from aircraft: randomized controlled trial

BMJ 2018; 363 doi: https://doi.org/10.1136/bmj.k5094 (Published 13 December 2018) Cite this as: BMJ 2018;363:k5094

Linked opinion

We jumped from planes without parachutes (and lived to tell the tale)

  1. Robert W Yeh, associate professor1,
  2. Linda R Valsdottir, research coordinator1,
  3. Michael W Yeh, professor2,
  4. Changyu Shen, director1,
  5. Daniel B Kramer, assistant professor1,
  6. Jordan B Strom, instructor1,
  7. Eric A Secemsky, instructor1,
  8. Joanne L Healy, administrative manager1,
  9. Robert M Domeier, expert skydiver and clinical instructor3,
  10. Dhruv S Kazi, associate director1,
  11. Brahmajee K Nallamothu, professor4
  12. on behalf of the PARACHUTE Investigators
  1. 1Richard A and Susan F Smith Center for Outcomes Research in Cardiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 375 Longwood Avenue, Boston, MA 02215, USA
  2. 2David Geffen School of Medicine, University of California, Los Angeles, CA, USA
  3. 3Department of Emergency Medicine, University of Michigan and Saint Joseph Hospital, Ann Arbor, MI, USA
  4. 4Michigan Integrated Center for Health Analytics and Medical Prediction, Department of Internal Medicine and Institute for Healthcare Policy and Innovation, University of Michigan, Ann Arbor, MI, USA
  1. Correspondence to: R W Yeh ryeh{at}bidmc.harvard.edu (or @rwyeh on Twitter)
  • Accepted 22 November 2018

Abstract

Objective To determine if using a parachute prevents death or major traumatic injury when jumping from an aircraft.

Design Randomized controlled trial.

Setting Private or commercial aircraft between September 2017 and August 2018.

Participants 92 aircraft passengers aged 18 and over were screened for participation. 23 agreed to be enrolled and were randomized.

Intervention Jumping from an aircraft (airplane or helicopter) with a parachute versus an empty backpack (unblinded).

Main outcome measures Composite of death or major traumatic injury (defined by an Injury Severity Score over 15) upon impact with the ground measured immediately after landing.

Results Parachute use did not significantly reduce death or major injury (0% for parachute v 0% for control; P>0.9). This finding was consistent across multiple subgroups. Compared with individuals screened but not enrolled, participants included in the study were on aircraft at significantly lower altitude (mean of 0.6 m for participants v mean of 9146 m for non-participants; P<0.001) and lower velocity (mean of 0 km/h v mean of 800 km/h; P<0.001).

Conclusions Parachute use did not reduce death or major traumatic injury when jumping from aircraft in the first randomized evaluation of this intervention. However, the trial was only able to enroll participants on small stationary aircraft on the ground, suggesting cautious extrapolation to high altitude jumps. When beliefs regarding the effectiveness of an intervention exist in the community, randomized trials might selectively enroll individuals with a lower perceived likelihood of benefit, thus diminishing the applicability of the results to clinical practice.

Footnotes

  • Contributors: RWY had the original idea but was reluctant to say it out loud for years. In a moment of weakness, he shared it with MWY and BKN, both of whom immediately recognized this as the best idea RWY will ever have. RWY and LRV wrote the first draft. CS, DBK, JBS, EAS, and JLH provided critical review. RMD provided subject matter expertise. DSK took this work to another satirical level. All authors suffered substantial abdominal discomfort from laughter. RWY worried that BKN would not keep his mouth shut until the Christmas issue was published. All authors had full access to the data in the study and can take responsibility for the integrity of the data and the accuracy of the data analysis. RWY is the guarantor. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.

  • Funding: There was no funding source for this study.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form and declare: no support from any organization for the submitted work; no financial relationships with any organizations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: This research has the ethical approval of the Institutional Review Board of the Beth Israel Deaconess Medical Center (protocol no 2018P000441).

  • Data sharing: Anonymized trial data are available from the corresponding author.

  • The manuscript’s guarantor (RWY) affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as originally planned have been explained.

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