Return of secondary findings in genomic sequencing: Military implications.

BACKGROUND: Genomic sequencing has become a widely used tool in clinical and research settings in both civilian and military healthcare systems. METHODS: In this paper, we consider potential military-specific implications of returning genomic sequencing secondary findings to ensure the proper protections, policies, and processes are in place for the use of this information. RESULTS: We specifically use two examples to highlight potential military implications of the return of secondary findings. CONCLUSION: Clinicians and researchers are strongly encouraged to consider the military implications of the return of results for informed consent of service members or their families undergoing clinical or research genomic sequencing.

Ambulatory Surgery Has Minimal Impact on Sleep Parameters: A Prospective Observational Trial.

STUDY OBJECTIVES: The presence of obstructive sleep apnea (OSA) in ambulatory surgical patients causes significant perioperative concern; however, few data exist to guide clinicians' management decisions. The objective of this study was to measure changes in perioperative sleep parameters among an ambulatory surgery population. METHODS: This study is a prospective, observational study of ambulatory patients undergoing orthopedic surgery on an extremity. Study subjects completed three unattended home sleep apnea tests: baseline before surgery, the first night after surgery (N1), and third night after surgery (N3). Anesthesia and surgical teams were blinded to study participation and patients received routine perioperative care. RESULTS: Two hundred three subjects were enrolled and 166 completed the baseline home sleep test. Sixty-six (40.0%) had OSA at baseline, 35 patients received a new diagnosis, and 31 patients had a previous diagnosis of OSA. Of those with a previous diagnosis, 20 (64.5%) were compliant with continuous positive airway pressure therapy. Respiratory event index and SpO2 nadir did not significantly change postoperatively from baseline. Cumulative percentage of time oxygen saturation < 90% significantly increased N1 as compared to baseline for all patients except for those with moderate to severe OSA. CONCLUSIONS: Ambulatory surgery had minimal effect on sleep parameters and there was no increase in adverse events among patients with either treated or untreated OSA. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Title: Evaluation of Sleep Disordered Breathing Following Ambulatory Surgery; Identifier: NCT01851798; URL: https://clinicaltrials.gov/ct2/show/study/NCT01851798.

Vital Signs and Physiologic Derangement in Patients With Thoracic Trauma in Iraq and Afghanistan.

BACKGROUND: Triage is the act of stratifying the need for medical attention. Effective triage must account for injury patterns and severity. Personnel making triage decisions must also consider the patients' physiologic states. Vital signs can possibly be used to assess for the presence of physiological derangements such as coagulopathy, acidosis, or a significant base deficit. Providers could use this knowledge to assist with triage at casualty collection points where laboratory studies or point of care testing may not be available. METHODS: With institutional approval, data were extracted from the Joint Theater Trauma Registry for all patients with thoracic trauma between 2002 and 2012. Patients were identified by International Statistical Classification of Diseases and Related Health Problems, 9th Revision (ICD-9) codes. Heart rate (HR), systolic blood pressure (SBP), and pulse pressure were correlated with coagulopathy (international normalization ratio ≥ 1.5), acidosis (pH < 7.2) or an elevated base deficit (>6) on admission. Sensitivity, specificity, positive predictive values, negative predictive values, and odds ratios were calculated. FINDINGS: HR > 100, SBP < 90, or pulse pressure <30 were associated with an increased risk for acidosis (odds ratio 3.06 [95% confidence interval 2.48-3.78], 4.72 [3.85-5.78], and 2.73 [2.15-3.48], respectively), coagulopathy (2.21 [1.72-2.83], 4.55 [3.57-5.80], and 2.73 [2.15-3.48], respectively), and base deficit >6 (2.17 [1.88-2.50], 3.48 [2.87-4.22], and 2.22 [1.78-2.77], respectively). HR was a moderately sensitive marker (0.74), whereas SBP was a specific marker (0.93). DISCUSSION: SBP < 90 is an effective marker for ruling in physiologic derangement after thoracic trauma. HR > 100 was associated with over twice the odds for physiologic derangement. Vital signs can be used to assess for physiologic derangement in the population studied and may help in triage.

Minute Ventilation Limitations of Two Field Transport Ventilators.

Knowledge of transport ventilator performance impacts patient safety. This study compared minute ventilation (VE) of the MOVES and Uni-Vent 731 when ventilating the VentAid Training Test Lung with compliance (C) ranging from 0.02 to 0.10 L/cm H2O and three different airway resistances (R) (none, Rp5, or Rp20). Tidal volume (VT) was 800 ± 25 mL. Respiratory rate was increased to ventilator's maximum or until auto-PEEP > 5 cm H2O. Respiratory parameters were recorded with the RSS 100HR Research Pneumotach. Data were reported as median (interquartile range). Peak inspiratory pressure (PIP) of the Uni-Vent and MOVES ranged from 22.3 (22.2-22.5) to 82.6 (82.2-83.2) and 20.8 (20.6-20.9) to 50.6 (50.2-50.9) cm H2O, respectively. VE of the Uni-Vent and MOVES ranged from 17.7 (17.7-17.7) to 31.5 (31.5-31.5) and 11.3 (10.5-11.3) to 20.2 (19.7-20.5) L/min, respectively. Linear regression demonstrated strong, negative correlation of VE with PIP for the MOVES (VE [L/min] = 26 - 0.31 × PIP [cm H2O], r = -0.97) but weak, positive correlation for the Uni-Vent (r = 0.05). Uni-Vent VE exceeded MOVES VE under each test condition (p = 0.0002). If patient VE requirements exceed those predicted by the MOVES regression equation, then using the Uni-Vent should be considered.

Air compressor battery duration with mechanical ventilation in a field anesthesia machine.

Compressed air to power field anesthesia machine ventilators may be supplied by air compressor with battery backup. This study determined the battery duration when the compPAC ventilator's air compressor was powered by NiCd battery to ventilate the Vent Aid Training Test Lung modeling high (HC = 0.100 L/cm H2O) and low (LC = 0.020 L/cm H2O) pulmonary compliance. Target tidal volumes (VT) were 500, 750, and 1,000 mL. Respiratory rate = 10 bpm, inspiratory-to-expiratory time ratio = 1:2, and fresh gas flow = 1 L/min air. N = 5 in each group. Control limits were determined from the first 150 minutes of battery power for each run and lower control limit = mean VT - 3SD. Battery depletion occurred when VT was below the lower control limit. Battery duration ranged from 185.8 (±3.2) minutes in the LC-1000 group to 233.3 (±3.6) minutes in the HC-750 group. Battery duration of the LC-1000 group was less than all others (p = 0.027). The differences among the non-LC-1000 groups were not clinically significant.

Tumescent technique without epinephrine for endovenous laser therapy and serum lidocaine concentration.

OBJECTIVE: Endovenous laser therapy (EVLT) requires tumescent lidocaine anesthesia. Although it is well known that the absorption of local anesthetic varies according to the injection site, little evidence exists establishing the maximum recommended safe dose for extravascular injections such as those used for EVLT. The aim of this study was to evaluate plasma concentration of lidocaine over time after administration of tumescent lidocaine during EVLT procedures in healthy volunteers. METHODS: Between January 2011 and February 2013, 10 healthy patients scheduled for an EVLT procedure performed in a hospital setting were recruited to participate in an observational study. For each subject, a total of 10 venous samples were obtained for analysis after surgical injection of the tumescent lidocaine solution (0.1% concentration). Samples were collected at baseline (before the surgical procedure start) and then every 30 minutes for the first 2 hours after the initial lidocaine injection. Thereafter, venous samples were obtained every 2 hours, with the last sample drawn 12 hours after the surgeon's initial lidocaine injection. All specimens were drawn from a dedicated intravenous catheter, immediately placed in a heparinized blood collection tube, and centrifuged for 10 minutes at 3000 rpm. Plasma was then removed with a pipette and stored at -70 °C until analyzed. Total and free plasma lidocaine concentrations were determined by immunoassay. Plasma lidocaine concentrations were normalized by peak concentration for statistical comparisons. RESULTS: Laboratory data were available for nine of the 10 volunteers. The mean total lidocaine dose administered was 6.38 (± 2.2) mg/kg (range, 3.57-10.7 mg/kg). The total lidocaine blood levels ranged from 0.48 (± 0.28) to 1.3 (± 0.49) mcg/mL. The free lidocaine blood levels ranged from nondetectable to 0.76 (± 0.43) mcg/mL. The average total time of injection for the group was 32.8 (± 10.0) minutes (range, 21-49 minutes). Among all dose ranges, both total and free lidocaine peak blood level ratios occurred at times 60 to 120 minutes (P < .05). No value considered in the statistical analysis exceeded 5 mcg/mL at any time. CONCLUSIONS: Tumescent lidocaine without epinephrine for EVLT procedures produces a peak serum concentration at 60 to 120 minutes. The peak plasma concentration as observed with the standard institutional dosing of tumescent lidocaine appeared below the threshold for human toxicity.

Field anesthesia machine ventilator oxygen consumption in models of high and low pulmonary compliance.

Field anesthesia machine ventilators powered by compressed gas are designed for remote locations that may lack a pipeline supply of O2. This study determined the O2 consumption of the compPAC ventilator powered by E cylinders when ventilating the Vent Aid Training Test Lung model of high (HC) and low (LC) pulmonary compliance. Consumed O2 was calculated after measuring the mass of O2 depleted from the E cylinder. Three tidal volumes (V(T)) were tested (500, 750, and 1000 mL). The HC and LC settings were 0.100 and 0.020 L/cm H2O, respectively. N = 5 in each group, respiratory rate = 10 bpm, and I:E ratio = 1:2. Data were collected for 20 minutes per run. O2 consumption was directly proportional to V(T) and inversely proportional to compliance. The amount of O2 consumed by the ventilator ranged from 2.19 (interquartile range [IQR] 2.18-2.26) L/min in the HC-500 mL V(T) group to 3.76 (IQR 3.76-3.79) L/min in the HC-1000 mL V(T) group (P = 0.027) and from 2.63 (IQR 2.60-2.66) L/min in the LC-500 V(T) mL group to 4.89 (IQR 4.81-5.05) L/min in the LC-1000 mL V(T) group (P = 0.027). The volume of ventilator drive gas was less than minute ventilation (V(E)) in all groups.

Oxygen consumption of a pneumatically controlled ventilator in a field anesthesia machine.

BACKGROUND: Field anesthesia machines (FAM) have been developed for remote locations where reliable supplies of compressed medical gases or electricity may be absent. In place of electricity, pneumatically controlled ventilators use compressed gas to power timing circuitry and actuate valves. We sought to determine the total O(2) consumption and ventilator gas consumption (drive gas [DG] plus pneumatic control [PC] gas) of a FAM's pneumatically controlled ventilator in mechanical models of high (HC) and low (LC) total thoracic compliance. METHODS: The amount of total O(2) consumed by the Magellan-2200 (Oceanic Medical Products, Atchison, KS) FAM with pneumatically controlled ventilator was calculated using the ideal gas law and the measured mass of O(2) consumed from E cylinders. DG to the bellows canister assembly was measured with the Wright Respirometer Mk 8 (Ferraris Respiratory Europe, Hertford, UK). PC gas consumption was calculated by subtracting DG and fresh gas flow (FGF) from the total O(2) consumed from the E cylinder. The delivered tidal volume (V(T)) was measured with a pneumotach (Hans Rudolph, KS City, MO). Three different V(T) were tested (500, 750, and 1000 mL) with two lung models (HC and LC) using the Vent Aid Training Test Lung (MI Instruments, Grand Rapids, MI). Respiratory variables included an I:E of 1:2, FGF of 1 L/min, and respiratory rate of 10 breaths/min. RESULTS: Total O(2) consumption was directly proportional to V(T) and inversely proportional to compliance. The smallest total O(2) consumption rate (including FGF) was 9.3 +/- 0.4 L/min in the HC-500 model and the largest was 15.9 +/- 0.5 L/min in the LC-1000 model (P < 0.001). The mean PC circuitry consumption was 3.9 +/- 0.24 L/min or 390 mL +/- 24 mL/breath. CONCLUSIONS: To prepare for loss of central DG supply, patient safety will be improved by estimating cylinder duration for low total thoracic compliance. Using data from the smaller compliance and greatest V(T) model (LC-1000), a full O(2) E cylinder would be depleted in <42 min, whereas a full H cylinder would last approximately 433 min.

Oxygen consumption with mechanical ventilation in a field anesthesia machine.

Field anesthesia machines (FAM) with gas-powered ventilators have been developed for remote locations that may not have a central supply of oxygen. These ventilators may rapidly deplete oxygen cylinders, especially in patients with decreased pulmonary compliance. Our goal in this study was to determine oxygen consumption rates with a contemporary FAM in models of high (HC) and low (LC) pulmonary compliance. Oxygen consumption rates were tested using D cylinders (initial pressure 1700 psig) and the Narkomed M FAM, which uses an air injector to decrease compressed gas consumption by entraining room air as part of the drive gas. Three different tidal volumes (Vt) were tested (500, 750, and 1000 mL) with HC and LC lung models, and the fresh gas flow rate was 1 L/min. Respiratory rate was constant at 10 breaths/min. Oxygen consumption varied directly with Vt and inversely with compliance, increasing from 4.8 +/- 0.07 L/min with the HC-500 mL Vt model to 6.2 +/- 0.05 L/min with the LC-1000 mL Vt model. D cylinder duration ranged from 56.8 +/- 0.4 to 73.6 +/- 1.0 minutes. Assuming oxygen fresh gas flow of 1 L/min, calculating tank duration with the fastest consumption rate underestimated the tank duration for more compliant and smaller Vt models but provided a greater margin of patient safety.

Economic analysis of an intraoperative cell salvage service.

UNLABELLED: In the United States, the cost of erythrocyte transfusion exceeds 1.3 billion dollars annually. The fear of viral disease transmission popularized intraoperative salvage to reduce the use of banked blood. Although the economics of this technique have been questioned, the financial variables in providing an intraoperative autotransfusion service have not been analyzed. We designed mathematical models to determine the most cost-effective strategy based on hospital caseload. Four models were analyzed with a spreadsheet to project costs of an intraoperative autotransfusion service when fully or partially outsourced, performed by a full-time technician employee, or performed by a cross-trained employee. The Partially Outsourced model was more economical than the Fully Outsourced model when the annual caseload exceeded 185 cases. The New Employee model became more economical than the Fully Outsourced model when the annual caseload exceeded 110 cases. The Cross-Trained model was the most economical when annual caseload exceeded 55 cases. IMPLICATIONS: Cross-training an employee as a cell salvage technician is more economical than outsourcing when caseload exceeds 55 per year.