Safety standards for stab-resistant body armour: a computer tomographic assessment of organ to skin distances

Determination of the appropriate catheter length and place for needle thoracostomy by using computed tomography scans of pneumothorax patients

INTRODUCTION

The primary goal of this study was to compare the chest wall thicknesses (CWT) at the 2nd intercostal space (ICS) at the mid-clavicular line (MCL) and 5th ICS at the mid-axillary line (MAL) in a population of patients with a CT confirmed pneumothorax (PTX). This result will help physicians to determine the optimum needle thoracostomy (NT) puncture site in patients with a PTX.

MATERIALS AND METHODS

All trauma patients who presented consecutively to A&E over a 12-month period were included. Among all the trauma patients with a chest CT (4204 patients), 160 were included in the final analysis. CWTs were measured at both sides and were compared in all subgroup of patients.

RESULTS

The average CWT for men on the 2nd ICS-MCL was 38mm and for women was 52mm; on the other hand, on the 5th ICS-MAL was 33mm for men and 38mm for women. On the 2nd ICS-MCL 17% of men and 48% of women; on the 5th ICS-MAL 13% of men and 33% of women would be inaccessible with a routine 5-cm catheter. Patients with trauma, subcutaneous emphysema and multiple rib fractures would have thicker CWT on the 2nd ICS-MCL. Patients with trauma, lung contusion, sternum fracture, subcutaneous emphysema and multiple rib fractures would have thicker CWT on the 5th ICS-MAL.

CONCLUSIONS

This study confirms that a 5.0-cm catheter would be unlikely to access the pleural space in at least 1/3 of female and 1/10 of male Turkish trauma patients, regardless of the puncture site. If NT is needed, the 5th ICS-MAL is a better option for a puncture site with thinner CWT.

Tomodensitometric survey of the distance between thoracic and abdominal vital organs and the wall according to BMI, abdominal diameter and gender: proposition of an indicative chart for the forensic activities

INTRODUCTION

Forensic doctors are frequently asked by magistrates when dealing principally with knife wounds, about the depth of the blade which may have penetrated the victim's body. Without the use of imaging, it is often difficult to respond to this question, even in an approximate way. Knowledge of the various distances between organs and the skin wall would allow an assessment to be made of the minimum blade length required to obtain the injuries observed. The objective of this study is thus to determine average distances between the vital organs of the thorax and abdomen, and the skin wall, taking into account the person's body mass index (BMI).

MATERIALS AND METHODS

This is a prospective single-center study, carried out over a 2-month period at University Hospital in Angers. A sample of 200 people was studied. The inclusion criteria were as follows: all patients coming to the radiology department and the emergency department for an abdominal, thoracic or thoraco-abdominal scan with injection. The exclusion criteria included patients presenting a large lymphoma, a large abdominal or retroperitoneal tumor, a tumor in one of the organs targeted by our study and patients presenting ascites. The organs focused on were: the pericardium, pleura, aorta, liver, spleen, kidneys, abdominal aorta and femoral arteries. The shortest distance between the organ and the skin wall was noted. Median distances were calculated according to gender, abdominal diameter and BMI.

RESULTS

We associated these values to propose an indicative chart which may be used by doctors in connection with their forensic activities.

DISCUSSION

The problem of the depth of a wound is frequently exposed to the expert. Without a reliable tool, it is difficult to value and a personal interpretation is often done. Even if, in current days, tomodensitometry is frequently done in vivo or after death, measurement can be difficult because of the local conditions. We classified values according to the different factors of fat repartition (BMI, abdominal diameter, gender). These tables, collectively used, permit evaluation of the distance between wall and thoracic or abdominal vital organs.

CONCLUSION

We suggest an indicative chart designed for forensic doctors in their professional life to help determine the minimum penetration length for a knife, which may wound a vital organ.

Emergency medicine techniques and the forensic autopsy

Emergency medicine measures often have to be carried out under suboptimal conditions in emergency situations and require invasive patient treatment. In the case of a fatal outcome these measures have to be evaluated at autopsy, regarding indications, correct implementation and possible complications. As well, alongside the more familiar procedures--such as endotracheal intubation, insertion of chest drains, external cardiac massage and cannulation of central and peripheral veins--there are alternative techniques being increasingly applied, that include new tools for the management of hemorrhagic shock, drug delivery and alternative airway management devices. On the one hand, all of these measures are essential for the survival and appropriate treatment of the injured and/or sick patient, but on the other hand they can damage the patient and thus contain a significant risk of both medical and forensic relevance for the patient and the physician. In the following review we provide an overview of established, new and alternative techniques for emergency airway management, administration of drugs and management of hemorrhagic shock. The aim is to facilitate the understanding and autopsy evaluation of current emergency medicine techniques.

Wounding patterns and human performance in knife attacks: optimising the protection provided by knife-resistant body armour

BACKGROUND

Stab attacks generate high loads, and to defeat them, armour needs to be of a certain thickness and stiffness. Slash attacks produce much lower loads and armour designed to defeat them can be far lighter and more flexible.

METHODS AND SUBJECTS

Phase 1: Human performance in slash attacks: 87 randomly selected students at the Royal Military College of Science were asked to make one slash attack with an instrumented blade on a vertically mounted target. No instructions on how to slash the target were given. The direction, contact forces and velocity of each attack were recorded. Phase 2: Clinical experience with edged weapon attacks: The location and severity of all penetrating injuries in patients attending the Glasgow Royal Infirmary between 1993 and 1996 were charted on anatomical figures.

RESULTS

Phase 1: Two types of human slash behaviour were evident: a 'chop and drag' blow and a 'sweep motion' type of attack. 'Chop and drag' attacks had higher peak forces and velocities than sweep attacks. Shoulder to waist blows (diagonal) accounted for 82% of attacks, 71% of attackers used a long diagonal slash with an average cut length of 34 cm and 11% used short diagonal attacks with an average cut length of 25 cm. Only 18% of attackers slashed across the body (short horizontal); the average measured cut length of this type was 28 cm. The maximum peak force for the total sample population was 212 N; the maximum velocity was 14.88 m s(-1). The 95 percentile force for the total sample population was 181 N and the velocity was 9.89 m s(-1). Phase 2: 431 of the 500 patients had been wounded with edged weapons. The average number of wounds sustained by victims in knife assaults was 2.4. The distribution of wounds by frequency and severity are presented.

CONCLUSIONS

Anti-slash protection is required for the arms, neck, shoulders, and thighs. The clinical experience of knife-attack victims provides information on the relative vulnerabilities of different regions of the body. It is anticipated that designing a tunic-type of Police uniform that is inherently stab and slash resistant will eventually replace the current obvious and often bulky extra protective vest. Attempts at making a combined garment will need to be guided by ergonomic considerations and field testing. A similar anatomical regional risk model might also be appropriate in the design of anti-ballistic armour and combined anti-ballistic and knife-resistant armour.

Ultrasound assessment of the vulnerability of the internal organs to stabbing: determining safety standards for stab-resistant body armour

Stab-resistant body armour may not always prevent the passage of a blade into the human body. The depth to which a knife may 'safely' enter the human body before it breaches the internal organs was explored by ultrasound scanning of 25 healthy volunteers. Variations in the minimum skin-to-organ distances for the organs as a function of posture are described. To determine the optimum body coverage by stab-resistant armour, the movement during the breathing cycle and the maximum exposure of the organs beneath the lower costal margin at full inspiration were measured. Although the population studied was small, trends in the vulnerability of the internal organs to the passage of a blade into the body were identified.