High-power lasers for directed-energy applications: reply.

The comment by Vorontsov and Weyrauch [Appl. Opt.55, 9950 (2016)APOPAI0003-693510.1364/AO.55.009950] is aimed at rebutting the critiques in Sprangle et al. [Appl. Opt.54, F201 (2015)APOPAI0003-693510.1364/AO.54.00F201] and Nelson et al. [Appl. Opt.55, 1757 (2016)APOPAI0003-693510.1364/AO.55.001757]. In the comment, Vorontsov and colleagues describe their experiments aimed at demonstrating the feasibility of coherent combining of lasers on a distant target, using relatively low-power lasers and a cooperative retro-reflective target. The Naval Research Laboratory has demonstrated the capability to project high power on a distant target by making use of an incoherent combining architecture. The proof-of-concept experiments were performed in a realistic environment without employing cooperative targets and without sophisticated adaptive optics instrumentation.

Laser beam self-focusing in turbulent dissipative media.

A high-power laser beam propagating through a dielectric in the presence of fluctuations is subject to diffraction, dissipation, and optical Kerr nonlinearity. A method of moments was applied to a stochastic, nonlinear enveloped wave equation to analyze the evolution of the long-term spot radius. For propagation in atmospheric turbulence described by a Kolmogorov-von Kármán spectral density, the analysis was benchmarked against field experiments in the low-power limit and compared with simulation results in the high-power regime. Dissipation reduced the effect of self-focusing and led to chromatic aberration.

Commercial tattooing as a potentially important source of hepatitis C infection. Clinical epidemiology of 626 consecutive patients unaware of their hepatitis C serologic status.

Tattooing in commercial tattoo parlors is known to transmit blood-borne viral infections, including hepatitis C virus (HCV), in other countries, but its contribution to the high population prevalence of HCV infection in the United States has been incompletely evaluated. Risk factors for blood-borne infection were assessed by physician's interview of 626 consecutive patients undergoing medical evaluation for spinal problems in 1991 and 1992 while unaware of their HCV status. Later all were screened for HCV infection with enzyme-linked immunosorbent assay (EIA-1 and EIA-2), and positives were confirmed with second-generation recombinant immunoblot assay (RIBA). Forty-three patients were seropositive for HCV (sample prevalence 6.9%, population-standardized prevalence 2.8%). Logistic regression analysis identified 4 independent risk factors for HCV infection: injection-drug use (adjusted prevalence odds ratio [OR] = 23.0; 95% confidence intervals [CI] = 7.5-70.6), ancillary hospital jobs held by men (OR = 9.6; 95% CI = 3.8-24.3), tattoos from commercial tattoo parlors (OR = 6.5; 95% CI = 2.9-14.8), and drinking > or = 3 6-packs of beer per month (OR = 4.0; 95% CI = 1.8-8.7). If causal, these 4 risk factors account for 91% of HCV infections, with tattooing explaining 41%, heavy beer drinking 23%, injection-drug use 17%, and ancillary health care jobs for men 8%. Transfusions, promiscuous sexual activity, bone grafts, acupuncture, perinatal or intimate transmission in families, and other modes were not independently associated with serologic evidence of HCV infection. Unlikely to be explained by confounding or incomplete disclosure of other risk factors, tattooing in commercial tattoo parlors may have been responsible for more HCV infections than injection-drug use.

Blunt versus penetrating subclavian artery injury: presentation, injury pattern, and outcome.

BACKGROUND: Subclavian artery (SCA) injuries are rare vascular injuries and may be difficult to manage. The majority of SCA injuries are secondary to penetrating trauma. The purpose of this report is to examine the injury patterns, diagnostic and therapeutic approaches, and outcome of patients with blunt and penetrating SCA injuries. METHODS: Retrospective review RESULTS: Fifty-six patients sustained SCA injuries (25 blunt, 31 penetrating). SCA injury location was evenly distributed between the proximal, middle, and distal SCA after penetrating trauma; proximal injuries were rare (2 of 25) with blunt mechanisms. A radial arterial pulse deficit was present in only 3 of 25 blunt injuries and 9 of 31 penetrating injuries. Complications occurred more commonly in both groups of patients with initial systolic blood pressures less than 90 mm Hg. Survival was 76% in blunt and 81% in penetrating groups; limb salvage was similar (92% in blunt and 97% in penetrating groups). Complete brachial plexus injuries were more common with blunt injuries. CONCLUSION: SCA injuries are rare vascular injuries with an associated high morbidity and mortality, regardless of mechanism. Blunt mechanisms result in more middle and distal injuries and more frequent complete brachial plexus injuries. Complications are related to the hemodynamic status of the patient upon presentation, and not to mechanism of injury.

The efficacy of magnetic resonance cholangiography for the evaluation of patients with suspected choledocholithiasis before laparoscopic cholecystectomy.

BACKGROUND: Endoscopic retrograde cholangiography is the most commonly utilized tool for the identification of common bile duct stones (CBDS) before laparoscopic cholecystectomy, whereas the role of magnetic resonance cholangiography (MRC) for patient evaluation before laparoscopic cholecystectomy is currently undefined. METHODS: We prospectively evaluated the efficacy of MRC for the identification of CBDS among patients with high risk for choledocholithiasis. Patient selection was based on clinical, sonographic, and laboratory criteria. Standard cholangiograms were obtained when possible for verification of MRC results. RESULTS: Ninety-nine patients underwent evaluation with preoperative MRC. CBDS was visualized in 30% of patients. MRC sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 85%, 90%, 77%, 94%, and 89%, respectively. CONCLUSIONS: MRC is useful for the evaluation of patients with suspected choledocholithiasis. Advantages of MRC include its noninvasive nature, ease of application, and accuracy in identifying and estimating the size of CBDS. Application of MRC in this setting reduces the need for diagnostic endoscopic retrograde cholangiography. Future investigations should be directed at the development of cost-effective utilization strategies for MRC application.

"The demographics of trauma in 1995" revisited: an assessment of the accuracy and utility of trauma predictions.

OBJECTIVE: In 1987, the article "The Demographics of Trauma in 1995" (DT95) attempted to predict the future needs of trauma centers based on changing population distributions. This article foresaw a relative increase in the number of injuries to the elderly and a relative decrease in total injuries. Based on these predictions, the paper recommended increasing the capabilities of existing trauma centers rather than developing new facilities. We compared these predictions to actual experience to validate this use of demographic data in trauma system planning. METHODS: The predictions of DT95 were compared with the available population and injury data from the U.S. Census Bureau and the Centers for Disease Control and Prevention using age-related cohort analysis. RESULTS: As predicted, the highest-growing segment was the population older than 65 years, which increased 18% to 33.5 million. Also, the rate of injury-related deaths per 100,000 decreased from 61.20 in 1985 to 57.98 in 1995. The number of fatal motor vehicle crashes decreased from 45,958 in 1985 to 43,484 in 1995. Against predictions, the number of firearm deaths in 1994 increased from 31,566 to 35,957. Accurate predictions were thus made for most trauma demographic categories using a combination of census predictions and existing trauma demographic patterns. The increase in firearm deaths, however, was not anticipated using these sources and suggested the potential development of a more violent society. CONCLUSIONS: Demographic projections assist in predicting the number and type of future injuries. Sociologic and economic factors also need to be considered in any predictive determinations of the true demand for trauma centers.

Are scene flights for penetrating trauma justified?

OBJECTIVE: To evaluate the medical efficacy of helicopter scene flights for patients with noncranial penetrating injuries. DESIGN: A retrospective review of 122 consecutive victims of noncranial penetrating injuries evacuated by helicopter from the scene of injury to a level I trauma center. There were no medical criteria for accepting or rejecting a request for a scene flight by any public safety agency or emergency medical service (EMS). Flights were dispatched if the weather permitted and if a helicopter was available. RESULTS: The majority of patients were critically wounded. Their average Revised Trauma Score was 10.6, and 15.6% of the patients died (19 of 122), including all 11 patients who required prehospital cardiopulmonary resuscitation. Helicopter transport from the scene did not hasten trauma center arrival for any of the 122 patients. Ninety-two of the first-responder EMS units (75.4%) were advanced life support units (ALS) with crews of paramedics. The remaining 30 (24.6%) first-responder EMS units were basic life support units (BLS) with crews of emergency medical technicians (EMTs). Six of 122 patients (4.9%) required medical interventions by the medical flight crews beyond the capabilities of the ground EMS personnel. Only 3 of the 92 patients (3.3%) treated by first-responding paramedics received medical interventions by the medical flight crews beyond those authorized for paramedics (one cricothyroidotomy and two needle thoracenteses). Two of the 30 patients (6.7%) treated by first-responding EMTs received medical interventions by the medical flight crews not authorized for the EMTs. The on-scene paramedics performed endotracheal intubation on 10 patients. However, because of subsequent clinical deterioration, the medical flight crews performed endotracheal intubations on nine additional patients. In addition, two patients intubated by the first-responding paramedics required reintubation by the medical flight crews. CONCLUSIONS: Scene flights in this metropolitan area for patients who suffered noncranial penetrating injuries demonstrated that these flights were not medically efficacious. This conclusion rests on the findings that arrival at a trauma center was not hastened by scene flights and that only 4.9% of patients required prehospital care by the medical flight crew beyond the capabilities of the first-responding EMS personnel (2.5 and 6.7% for ALS and BLS responders, respectively). Based on this experience, we believe that in metropolitan areas, scene flights for victims of noncranial penetrating injuries should be restricted to critically injured patients likely to require prehospital care by the medical flight crew that is beyond the capabilities of the first responders or when the scene flight is likely to significantly hasten the arrival of the injured patient to an appropriate trauma center.

Traumatic lung herniation.

Traumatic lung herniation is a poorly described entity. An important factor in the etiology of these lesions is the relative lack of muscular support afforded by the anterior thorax. We report a case of blunt thoracic trauma complicated by an incarcerated lung herniation.

The pocket laser pointer as a teaching tool in laparoscopic surgery.

The common pen-sized laser pointer can be used during laparoscopic procedures to indicate landmarks on the video screen and facilitate communication between surgeon and the assistants. We describe a simple and inexpensive technique that allows scrubbed members of the surgical team to use the laser pointer without the need to sterilize the instrument.

Does the potential for organ donation justify scene flights for gunshot wounds to the head?

OBJECTIVE: The goal of this study was to evaluate helicopter transport to an urban level I trauma center from the scene of injury for patients with self-inflicted gunshot wounds to the head. DESIGN: This study is a retrospective review of the prehospital, hospital, and billing records. MEASUREMENTS AND MAIN RESULTS: Despite the fact that 10 of 28 patients (36%) had an airway established by the medical flight crews, scene flights did not enhance survival. Twenty-seven of 28 patients (96%) died. The remaining patient's survival could not be attributed to the scene flight. We estimated that 27 of 28 patients would have arrived at the trauma center sooner if they had been transported by the first-responder emergency medical services ground unit. Flight service charges were approximately one-third of the hospital charges. As a group, patients with a self-inflicted gunshot wound to the head had the highest rate of organ donation in this trauma center (26%). Twenty-nine organs were harvested from the seven donors. CONCLUSIONS: The use of helicopter scene flights from the scene of injury for patients with a self-inflicted gunshot wound to the head provides no medical advantage to the victims, but provides a high-yield source of desperately needed organs. The prompt establishment of an airway in the field may prolong patient survival long enough to allow evaluation for organ donation. Helicopter transport of these patients is justified only as a means of rapidly delivering the personnel capable of providing advanced airway skills to the scene. Patients requiring CPR in the field after isolated gunshot wounds to the head will not live long enough to become organ donor candidates; therefore, there is no benefit to helicopter transport for these patients.

Tampon occlusion of colostomy stoma during laparotomy.

A new technique for the occlusion of the colostomy stoma during colostomy takedown is prevented. Utilization of this technique prevents contamination and allows maintenance of colostomy length for anastomosis. It can be easily and safely performed.

The spectrum of blunt injury to the carotid artery: a multicenter perspective.

The relative infrequency of blunt carotid artery trauma prompted a multicenter review to determine the spectrum of injuries, treatment strategies, and neurologic outcome. During a six-year period, 60 carotid artery injuries from blunt mechanisms in 49 patients were treated at 11 institutions. There were 11 bilateral injuries. Injury mechanisms were diverse but involved motor vehicles in 35 (72%) patients. In 14 (29%) patients, significant neurologic deficits developed more than 12 hours after a normal admission neurologic examination. The diagnosis was confirmed by angiography in 42 (86%). Duplex ultrasound accurately demonstrated the arterial injury in 12 (86%) of 14 patients. Documented injuries included arterial thrombosis in 20 arteries, arterial dissection alone in 19, dissection with pseudoaneurysm in six, pseudoaneurysm alone in five, frank arterial disruption in seven, and carotid-cavernous fistula in three. Arterial dissection was managed nonsurgically in 15 (79%) of 19 cases, the majority with systemic anticoagulation. Arterial thrombosis was managed with supportive therapy alone for 16 (80%) of 20 arteries; most associated with fixed neurologic deficits. Pseudoaneurysm repair was performed for six (55%) injuries. Carotid-cavernous fistulas were treated in all three instances with balloon occlusion. Overall mortality was 16 of 49 patients (43%). Good neurologic outcome was achieved in 22 (45%) patients. We conclude that: (1) Neurologic symptoms may develop in a delayed fashion; prior clinical suspicion and diagnostic testing are essential; (2) arterial dissection without complete occlusion may effectively be managed by anticoagulation; (3) pseudoaneurysms in accessible anatomic locations can be repaired with good results; and (4) injuries with complete arterial thrombosis are associated with high mortality and poor neurologic outcome in proportion to the initial degree of neurologic impairment.

A multicenter trial for resuscitation of injured patients with 7.5% sodium chloride. The effect of added dextran 70. The Multicenter Group for the Study of Hypertonic Saline in Trauma Patients.

OBJECTIVE: To evaluate the use of 250 mL of a 7.5% sodium chloride solution, both with and without added dextran 70, for the prehospital resuscitation of hypotensive trauma patients. DESIGN: Double-blind randomized trial. SETTING: Six trauma systems served by helicopter transport. PATIENTS: Injured patients with systolic blood pressures less than 90 mm Hg at any time in the field or during helicopter transport. INTERVENTIONS: Infusion of study solution, in the field or during transport, followed by conventional isotonic solutions as needed. Solutions studied in four cohorts were as follows: (1) lactated Ringer's; (2) 7.5% sodium chloride (hypertonic saline); (3) 7.5% sodium chloride combined with 6% dextran 70; and (4) 7.5% sodium chloride combined with 12% dextran 70. MAIN OUTCOME MEASURES: Blood pressure response; survival to time of hospital discharge among the treatment groups; and survival compared with that predicted by norms from the Major Trauma Outcome Study (MTOS). RESULTS: The mean (+/- SD) change in systolic blood pressure on arrival in the emergency department was significantly higher in the hypertonic saline solution group than that in the lactated Ringer's solution group (34 +/- 46 vs 11 +/- 49 mm Hg, P < .03). Overall survival in the four treatment groups was 49%, 60%, 56%, and 45% (not statistically significant). Survival in the hypertonic saline solution group, however, was significantly higher than that predicted by the MTOS norms (60% vs 48%, P < .001). Survival to hospital discharge in patients with baseline Glasgow Coma Scale scores of 8 or less was correlated with treatment group (P < .05 by logistic regression and P < .01 by Cox proportional-hazards analysis; with survival in the hypertonic saline solution group [34%] vs lactated Ringer's solution group [12%]). CONCLUSIONS: Prehospital infusion of 250 mL of 7.5% sodium chloride is associated with an increase in blood pressure and an increase in survival to hospital discharge compared with survival predicted by the MTOS norms. Patients with low baseline Glasgow Coma Scale scores seem to benefit the most from 7.5% sodium chloride resuscitation. Hypertonic saline solution without added dextran 70 is as effective as the more expensive solutions that contain dextran 70.

Continuing evolution in the approach to severe liver trauma.

Surgical and radiologic techniques from computed tomography (CT) scanning and embolization to temporary gauze packing and mesh hepatorrhaphy have been developed to make the management of severe liver injuries more effective. Surgical approaches for severe liver trauma have been oriented to two major consequences of these injuries: hemorrhage and infection. Early attempts at hemorrhagic control found benefit only in temporary intrahepatic gauze packing. The subsequent recognition of complications after liver injury blamed the practice of packing, which then remained unused for more than 30 years. Yet more aggressive attempts at controlling hemorrhage without temporary packing failed to improve results. Temporary perihepatic gauze packing therefore has been reintroduced, but this is probably an imperfect solution. Mesh hepatorrhaphy may control bleeding without many of the adverse effects of packing. Fourteen patients are reported with severe liver injuries who have undergone mesh hepatorrhaphy, bringing the current reported experience with mesh hepatorrhaphy to 24, with a combined mortality rate of 37.5%. Thus far, it appears that only juxtacaval injuries fail to have their hemorrhage controlled with mesh hepatorrhaphy, but many believe that these injuries may be controlled by perihepatic packing. Prophylactic drainage of severe liver injuries is a concept for which there is little evidence of benefit. Furthermore, recent radiologic developments appear capable of draining those collections that do occasionally develop in the postoperative period. The ultimate challenge of liver transplantation for trauma has been attempted, but the experience is thus far very limited.

The disparity between hypothermic coagulopathy and clotting studies.

Hypothermic patients commonly develop coagulopathy, but the effects of hypothermia on coagulation remain unclear because clinical laboratories routinely perform clotting tests only at 37 degrees C. Measurements of activated partial thromboplastin times (APTT), prothrombin times (PT), and thrombin times (TT) were performed on plasma from normothermic and hypothermic rats at a range of temperatures (25 degrees-37 degrees C) to assess the effects of hypothermia on apparent clotting factor levels and clotting factor activities. In general, clotting times were more severely prolonged when test temperatures were hypothermic than when body temperatures were hypothermic. Indeed, little to no prolongation resulted from body hypothermia alone. These findings reveal the observed disparity between clinically evident hypothermic coagulopathy and near-normal clotting studies. Clotting studies performed at 37 degrees C will not confirm hypothermic coagulopathy. These results indicate that the appropriate treatment for hypothermia-induced coagulopathy is rewarming rather than administration of clotting factors.

Mucormycosis in trauma patients.

Cutaneous mucormycosis is a rare but often fatal infection in trauma patients. We retrospectively reviewed a 9-year experience with mucormycosis among injured patients. Eleven patients had biopsy- or culture-proven mucormycosis. Nine patients were victims of blunt trauma, two patients had burns measuring greater than 50% TBSA. No patient was at increased risk because of underlying disease or immunosuppression prior to injury. All 11 patients had open wounds on admission. Four patients died of mucormycosis. All nonsurvivors had phycomycotic gangrenous cellulitis of the head, the trunk, or both. In contrast, survivors had involvement of only the extremities. Because of underlying disease, contaminating wounds, antibiotic use, or immunocompromise secondary to shock and sepsis, trauma patients are at risk of developing mucormycosis. To successfully treat mucormycosis, diagnosis must be prompt and accompanied by aggressive debridement and parenteral administration of amphotericin B.

The pharmacokinetics of prophylactic antibiotics in trauma.

Despite prophylactic antibiotic use in abdominal trauma patients, infection rates remain high. A previous study from our institution indicated that higher doses of prophylactic antibiotics in trauma patients could significantly reduce subsequent infection rates. To determine if this resulted from altered pharmacokinetic profiles, we performed individualized pharmacokinetic analysis of the prophylactic amikacin regimens given to 28 trauma patients undergoing laparotomy. Patients were prospectively randomized to receive a standard regimen of 11 mg/kg of amikacin every 12 hours or to have their regimens adjusted based upon pharmacokinetic analysis. Repeated pharmacokinetic analyses were performed daily for the three-day prophylactic regimen. There was a significant expansion in the apparent volume of distribution for amikacin that correlated with fluid resuscitation. This, along with increased elimination rates, helps to explain the failure to achieve adequate amikacin levels using standard regimens in trauma patients. Such underdosing may contribute to relatively high infection rates following major abdominal injury.

Hypertonic saline alters plasma clotting times and platelet aggregation.

Hypertonic (7.5%) saline (HS) is advocated for resuscitation of injured and burned patients. Recent animal studies indicate that HS increases bleeding during uncontrolled hemorrhage, although the mechanisms for this are unclear. To investigate potential anticoagulant effects of HS (without dextran), normal human plasma was serially diluted with either HS or normal (0.9%) saline (NS). Prothrombin times (PT), activated partial thromboplastin times (APTT), and platelet aggregation studies were performed. Significant (p less than 0.05) deteriorations in clotting tests and platelet aggregation developed when 10% or more of normal plasma was replaced by HS, whereas there was no effect from similar NS dilutions. Strong correlations were observed between clotting test changes and sodium concentrations (R2 greater than 0.80, p less than 0.0001). Thus, HS exhibits anticoagulant activity, but not at the usual small volumes necessary to produce hemodynamic improvement. Nevertheless, the anticoagulant effect may be more pronounced with ongoing clotting factor losses or with the addition of dextran.

Hypothermia and blood coagulation: dissociation between enzyme activity and clotting factor levels.

Previous studies of hypothermia and blood coagulation have focused on alterations in the levels of blood clotting elements using coagulation tests performed under normothermic conditions. However, because of the enzymatic nature of activated clotting factors, hypothermia should also be expected to affect clotting factor activities. Multiple determinations of activated partial thromboplastin times (APTT), prothrombin times (PT), and thrombin times (TT) were performed on commercially available normal human plasma at assay temperatures similar to those encountered clinically (25-37 degrees C). Both the APTT and the PT were significantly prolonged at temperatures below 35 degrees C (P less than 0.05). Clotting time correlated significantly with assay temperature in a negative exponential fashion for all three tests (r = -0.97 for APTT, -0.93 for PT, -0.71 for TT, P less than 0.001 for all regressions). Clotting time prolongation appears proportional to the number of enzymatic steps involved. These data indicate that the coagulopathy observed during hypothermia is, in part, independent of clotting factor levels.

Geographic patterns of urban trauma according to mechanism and severity of injury.

UNLABELLED: The purpose of this study was to investigate the distribution of various mechanisms of injury and the relative severity of such injury cases throughout the different geographic zones of a large urban area using a computerized emergency medical services (EMS) dispatch/patient record database. The study city (population, 2 million residents) was divided into 156 geographic grids (each 4.5 by 3 miles) and the incidence and relative severity of various injury mechanisms were determined for each zone. RESULTS: In one year (1988), there were more than 115,000 separate EMS incidents involving more than 150,000 patients, 26,000 of whom were transported for injuries incurred in 10,064 motor vehicle accidents, 4,587 falls, 4,015 lacerations/stabwounds, 1,796 beatings, 1,270 gunshots, and 952 auto-pedestrian accidents. Analysis of the 156 zones showed a disproportionate number of EMS responses in the city center with two centralmost grids accounting for about 25% of all responses. Call volume then progressively diminished toward the periphery of the city. However, with some very minor exceptions, the relative incidence and severity of the various injury mechanisms remained proportionally uniform within each zone, regardless of geographic location. Therefore, contrary to popular notoriety, the incidence and associated severity of any given injury type generally was not necessarily predicted by any particular neighborhood predilection for it, but rather by the overall demand for EMS in that zone of the city.