Man with HIV needle // shoot or not?

[afrattner]

1.unholster
2.side ready
3.sights on target, finger on trigger
4.Tell him or her, to stay back and put the crap on the ground and back away
5.If not, 1 shot at center of seen mass
6.sights off target, finger off trigger
7.side ready
8.re-holster
9.call police

Aids or no aids, you dont know. Its like a replica firearm, you dont know.

Any bio-hazard is a risk to life or harm, so your within your right.

[rnestved]

I agree the genius is a threat, and stupid should hurt. The question I have is in regards to PA law. Does holding a syringe with a threat of stabbing you pose an immediate risk to your life justify a lethal response from me. Comparitively if a LEO responded, I would think that the use of a taser would be the neutralizing device of choice. Here is some text on the amount of air needed to be injected to cause complications/lethal insult:

Venous Air Embolism
Author: Brenda Liz Natal, MD, Clinical Assistant Instructor and Staff Physician, Department of Emergency Medicine, Kings County Hospital and State University of New York Downstate, Brooklyn
Coauthor(s): Christopher I Doty, MD, FACEP, FAAEM, Assistant Professor of Emergency Medicine, Residency Program Director, Department of Emergency Medicine, Kings County Hospital Center, State University of New York Downstate Medical Center
Contributor Information and Disclosures

Updated: Jul 27, 2009



Pathophysiology
Two preconditions must exist for venous air embolism to occur: (1) a direct communication between a source of air and the vasculature and (2) a pressure gradient favoring the passage of air into the circulation.12,4

The key factors determining the degree of morbidity and mortality in venous air emboli are related to the volume of gas entrainment, the rate of accumulation, and the patient’s position at the time of the event.1,6,11

Generally, small amounts of air are broken up in the capillary bed and absorbed from the circulation without producing symptoms. Traditionally, it has been estimated that more than 5 mL/kg of air displaced into the intravenous space is required for significant injury (shock or cardiac arrest) to occur.1 However, complications have been reported with as little as 20 mL of air7 (the length of an unprimed IV infusion tubing) that was injected intravenously. The injection of 2 or 3 mL of air into the cerebral circulation can be fatal.13 Furthermore, as little as 0.5 mL of air in the left anterior descending coronary artery has been shown to cause ventricular fibrillation.13,9 Basically, the closer the vein of entrainment is to the right heart, the smaller the lethal volume is.1

Rapid entry or large volumes of air entering the systemic venous circulation puts a substantial strain on the right ventricle, especially if this results in a significant rise in pulmonary artery (PA) pressures. This increase in PA pressure can lead to right ventricular outflow obstruction and further compromise pulmonary venous return to the left heart. The diminished pulmonary venous return will lead to decreased left ventricular preload with resultant decreased cardiac output and eventual systemic cardiovascular collapse.1,4,6

With venous air embolism (VAE), resultant tachyarrhythmias are frequent, but bradyarrhythmias can also occur.4,2

The rapid ingress of large volumes of air (>0.30 mL/kg/min) into the venous circulatory system can overwhelm the air-filtering capacity of the pulmonary vessels, resulting in a myriad of cellular changes.3 The air embolism effects on the pulmonary vasculature can lead to serious inflammatory changes in the pulmonary vessels; these include direct endothelial damage and accumulation of platelets, fibrin, neutrophils, and lipid droplets.1

Secondary injury as a result of the activation of complement and the release of mediators and free radicals can lead to capillary leakage and eventual noncardiogenic pulmonary edema.1,7,3

Alteration in the resistance of the lung vessels and ventilation-perfusion mismatching can lead to intra-pulmonary right-to-left shunting and increased alveolar dead space with subsequent arterial hypoxia and hypercapnea.1,4,11

Arterial embolism as a complication of venous air embolism (VAE) can occur through direct passage of air into the arterial system via anomalous structures such as an atrial or ventricular septal defect, a patent foramen ovale, or pulmonary arterial-venous malformations. This can cause paradoxical embolization into the arterial tree.1,4,9,2,3 The risk for a paradoxical embolus seems to be increased during procedures performed in the sitting position.1,5

Air embolism has also been described as a potential cause of the systemic inflammatory response syndrome (case report), triggered by the release of endothelium derived cytokines.12 ..............


Now for the HIV/pathogen risk. Like stated before HIV is very fragile and quickly dies outside the host. A bigger risk is Hepatitis and the other nasties. But a needlestick is a low transmission risk, unless material is actually injected, than it is another ball game. Lot of variables there. Also some opportunities for early antiviral treatment to counter any possible infection...thats a whole other story.

I persoanlly would drop the guy with 2 center of mass shots and reevaluate the threat. I think with a good attorney a case for justifiable homicide could be argued and won. Just my thoughts.
Robert

[emsjeep]

I agree the genius is a threat, and stupid should hurt. The question I have is in regards to PA law. Does holding a syringe with a threat of stabbing you pose an immediate risk to your life justify a lethal response from me. Comparitively if a LEO responded, I would think that the use of a taser would be the neutralizing device of choice. Here is some text on the amount of air needed to be injected to cause complications/lethal insult:

Venous Air Embolism
Author: Brenda Liz Natal, MD, Clinical Assistant Instructor and Staff Physician, Department of Emergency Medicine, Kings County Hospital and State University of New York Downstate, Brooklyn
Coauthor(s): Christopher I Doty, MD, FACEP, FAAEM, Assistant Professor of Emergency Medicine, Residency Program Director, Department of Emergency Medicine, Kings County Hospital Center, State University of New York Downstate Medical Center
Contributor Information and Disclosures

Updated: Jul 27, 2009



Pathophysiology
Two preconditions must exist for venous air embolism to occur: (1) a direct communication between a source of air and the vasculature and (2) a pressure gradient favoring the passage of air into the circulation.12,4

The key factors determining the degree of morbidity and mortality in venous air emboli are related to the volume of gas entrainment, the rate of accumulation, and the patient’s position at the time of the event.1,6,11

Generally, small amounts of air are broken up in the capillary bed and absorbed from the circulation without producing symptoms. Traditionally, it has been estimated that more than 5 mL/kg of air displaced into the intravenous space is required for significant injury (shock or cardiac arrest) to occur.1 However, complications have been reported with as little as 20 mL of air7 (the length of an unprimed IV infusion tubing) that was injected intravenously. The injection of 2 or 3 mL of air into the cerebral circulation can be fatal.13 Furthermore, as little as 0.5 mL of air in the left anterior descending coronary artery has been shown to cause ventricular fibrillation.13,9 Basically, the closer the vein of entrainment is to the right heart, the smaller the lethal volume is.1

Rapid entry or large volumes of air entering the systemic venous circulation puts a substantial strain on the right ventricle, especially if this results in a significant rise in pulmonary artery (PA) pressures. This increase in PA pressure can lead to right ventricular outflow obstruction and further compromise pulmonary venous return to the left heart. The diminished pulmonary venous return will lead to decreased left ventricular preload with resultant decreased cardiac output and eventual systemic cardiovascular collapse.1,4,6

With venous air embolism (VAE), resultant tachyarrhythmias are frequent, but bradyarrhythmias can also occur.4,2

The rapid ingress of large volumes of air (>0.30 mL/kg/min) into the venous circulatory system can overwhelm the air-filtering capacity of the pulmonary vessels, resulting in a myriad of cellular changes.3 The air embolism effects on the pulmonary vasculature can lead to serious inflammatory changes in the pulmonary vessels; these include direct endothelial damage and accumulation of platelets, fibrin, neutrophils, and lipid droplets.1

Secondary injury as a result of the activation of complement and the release of mediators and free radicals can lead to capillary leakage and eventual noncardiogenic pulmonary edema.1,7,3

Alteration in the resistance of the lung vessels and ventilation-perfusion mismatching can lead to intra-pulmonary right-to-left shunting and increased alveolar dead space with subsequent arterial hypoxia and hypercapnea.1,4,11

Arterial embolism as a complication of venous air embolism (VAE) can occur through direct passage of air into the arterial system via anomalous structures such as an atrial or ventricular septal defect, a patent foramen ovale, or pulmonary arterial-venous malformations. This can cause paradoxical embolization into the arterial tree.1,4,9,2,3 The risk for a paradoxical embolus seems to be increased during procedures performed in the sitting position.1,5

Air embolism has also been described as a potential cause of the systemic inflammatory response syndrome (case report), triggered by the release of endothelium derived cytokines.12 ..............


Now for the HIV/pathogen risk. Like stated before HIV is very fragile and quickly dies outside the host. A bigger risk is Hepatitis and the other nasties. But a needlestick is a low transmission risk, unless material is actually injected, than it is another ball game. Lot of variables there. Also some opportunities for early antiviral treatment to counter any possible infection...thats a whole other story.

I persoanlly would drop the guy with 2 center of mass shots and reevaluate the threat. I think with a good attorney a case for justifiable homicide could be argued and won. Just my thoughts.
Robert

Without dragging myself through that I can tell you that it depends alot on the individual but generally between 8-15cc of air will be enough to kill you or cause big problems that I would not like to deal with 15-30cc will drop you for good without a doubt. The chance of them getting venous access directly by stabbing you with a needle is near zero. If you have ever started an IV, you know this. 30cc for a 100kg individual is, by conventional teachings, and thus the standard by which you will be judged, is an overestimation...at least for a rapid bolus.