Shock and Vasopressors.

Shock is a life-threatening condition carrying a high mortality rate when untreated. The consequences of shock are cellular and metabolic derangements, which are initially reversible. The authors present the case of a Servicemember who sustained mortar shrapnel wounds that resulted in shock.

Mechanical Ventilation: A Review for Special Operations Medical Personnel.

Mechanical ventilation is machine-delivered flow of gases to both oxygenate and ventilate a patient who is unable to maintain physiological gas exchange, and positive-pressure ventilation (PPV) is the primary means of delivering invasive mechanical ventilation. The authors review invasive mechanical ventilation to give the Special Operations Force (SOF) medic a comprehensive conceptual understanding of a core application of critical care medicine.

The relationship of tidal volume and driving pressure with mortality in hypoxic patients receiving mechanical ventilation.

PURPOSE: To determine whether tidal volume/predicted body weight (TV/PBW) or driving pressure (DP) are associated with mortality in a heterogeneous population of hypoxic mechanically ventilated patients. METHODS: A retrospective cohort study involving 18 intensive care units included consecutive patients ≥18 years old, receiving mechanical ventilation for ≥3 days, with a PaO2/FiO2 ratio ≤300 mmHg, whether or not they met full criteria for ARDS. The main outcome was hospital mortality. Multiple logistic regression (MLR) incorporated TV/PBW, DP, and potential confounders including age, APACHE IVa® predicted hospital mortality, respiratory system compliance (CRS), and PaO2/FiO2. Predetermined strata of TV/PBW were compared using MLR. RESULTS: Our cohort comprised 5,167 patients with mean age 61.9 years, APACHE IVa® score 79.3, PaO2/FiO2 166 mmHg and CRS 40.5 ml/cm H2O. Regression analysis revealed that patients receiving DP one standard deviation above the mean or higher (≥19 cmH20) had an adjusted odds ratio for mortality (ORmort) = 1.10 (95% CI: 1.06-1.13, p = 0.009). Regression analysis showed a U-shaped relationship between strata of TV/PBW and adjusted mortality. Using TV/PBW 4-6 ml/kg as the referent group, patients receiving >10 ml/kg had similar adjusted ORmort, but those receiving 6-7, 7-8 and 8-10 ml/kg had lower adjusted ORmort (95%CI) of 0.81 (0.65-1.00), 0.78 (0.63-0.97) and 0.80 0.67-1.01) respectively. The adjusted ORmort in patients receiving 4-6 ml/kg was 1.26 (95%CI: 1.04-1.52) compared to patients receiving 6-10 ml/kg. CONCLUSIONS: Driving pressures ≥19 cmH2O were associated with increased adjusted mortality. TV/PBW 4-6ml/kg were used in less than 15% of patients and associated with increased adjusted mortality compared to TV/PBW 6-10 ml/kg used in 82% of patients. Prospective clinical trials are needed to prove whether limiting DP or the use of TV/PBW 6-10 ml/kg versus 4-6 ml/kg benefits mortality.

An overview of modern embolic protection in percutaneous coronary intervention.

Coronary embolism due to atherosclerotic debris is a rather common cause of post-procedural complications. While evidence has shown that both arteriolar vasodilators and platelet glycoprotein inhibitors have proven ineffective against post- and peri-procedural embolism,5 mechanical interventional devices have been shown to improve (lower) 30-day MACE rates. These interventions include distal filtration, distal, and proximal occlusion balloons. The distal occlusion balloon was the first approach to embolic protection. The intervention involves placement of a low pressure (<2 atm) balloon distal to the lesion of interest. Antegrade flow is temporarily interrupted while the lesion is treated. Mounted on conventional 0.014-inch guidewire shafts, distal filtration systems follow a similar intervention method to distal occlusion. In this proceeding, a delivery/recovery sheath catheter deploys an expandable filter device approximating the lumen, which is later removed following PTCA or stent placement in retroversion. The variety of existing, rather novel filter designs typically feature a wire mounted umbrella-type filter consisting of laser-drilled micropores design varied, averaging approximately 100 microm. The primary benefit derived of distal filtration includes the trivial uninterruption of antegrade flow. Unlike distal occlusion, proximal devices allow for vessel protection before lesion crossing, a great advantage in cases involving thrombosis, vulnerable plaque, or primary unstable angina. Proximal occlusion follows a nearly identical implementation as distal occlusion. While substantial research is still needed, interventionalists are advised to always use embolic protection devices in SVG interventions.