Minimizing Lung Injury During Laparoscopy in Head-Down Tilt: A Physiological Cohort Study.

BACKGROUND: Increased intra-abdominal pressure during laparoscopy induces atelectasis. Positive end-expiratory pressure (PEEP) can alleviate atelectasis but may cause hyperinflation. Cyclic opening of collapsed alveoli and hyperinflation can lead to ventilator-induced lung injury and postoperative pulmonary complications. We aimed to study the effect of PEEP on atelectasis, lung stress, and hyperinflation during laparoscopy in the head-down (Trendelenburg) position. METHODS: An open-label, repeated-measures, interventional, physiological cohort trial was designed. All participants were recruited from a single tertiary Belgian university hospital. Twenty-three nonobese patients scheduled for laparoscopy in the Trendelenburg position were recruited.We applied a decremental PEEP protocol: 15 (high), 10 and 5 (low) cm H 2 O. Atelectasis was studied with the lung ultrasound score, the end-expiratory transpulmonary pressure, the arterial oxygen partial pressure to fraction of inspired oxygen concentration (P ao2 /Fi o2 ) ratio, and the dynamic respiratory system compliance. Global hyperinflation was evaluated by dead space volume, and regional ventilation was evaluated by lung ultrasound. Lung stress was estimated using the transpulmonary driving pressure and dynamic compliance. Data are reported as medians (25th-75th percentile). RESULTS: At 15, 10, and 5 cm H 2 O PEEP, the respective measurements were: lung ultrasound scores (%) 11 (0-22), 27 (11-39), and 53 (42-61) ( P < .001); end-expiratory transpulmonary pressures (cm H 2 O) 0.9 (-0.6 to 1.7), -0.3 (-2.0 to 0.7), and -1.9 (-4.6 to -0.9) ( P < .001); P ao2 /Fi o2 ratios (mm Hg) 471 (435-538), 458 (410-537), and 431 (358-492) ( P < .001); dynamic respiratory system compliances (mL/cm H 2 O) 32 (26-36), 30 (25-34), and 27 (22-30) ( P < .001); driving pressures (cm H 2 O) 8.2 (7.5-9.5), 9.3 (8.5-11.1), and 11.0 (10.3-12.2) ( P < .001); and alveolar dead space ventilation fractions (%) 10 (9-12), 10 (9-12), and 9 (8-12) ( P = .23). The lung ultrasound score was similar between apical and basal lung regions at each PEEP level ( P = .76, .37, and .76, respectively). CONCLUSIONS: Higher PEEP levels during laparoscopy in the head-down position facilitate lung-protective ventilation. Atelectasis and lung stress are reduced in the absence of global alveolar hyperinflation.

A low dose of three local anesthetic solutions for interscalene blockade tested by thermal quantitative sensory testing: a randomized controlled trial.

This randomized double-blind controlled trial compared the block characteristics of three low-dose local anesthetics at different roots in an ultrasound-guided interscalene block, using thermal quantitative sensory testing for assessing the functioning of cutaneous small nerve fibres. A total of 37 adults scheduled to undergo shoulder arthroscopy were randomized to receive 5 mL of either 0.5% levobupivacaine with and without epinephrine 1/200,000 or 0.75% ropivacaine in a single-shot interscalene block. Thermal quantitative sensory testing was performed in the C4, C5, C6 and C7 dermatomes. Detection thresholds for cold/warm sensation and cold/heat pain were measured before and at 30 min, 6, 10 and 24 h after infiltration around C5. The need for rescue medication was recorded. No significant differences between groups were found for any sensation (lowest P = 0.28). At 6 h, the largest differences in sensory thresholds were observed for the C5 dermatome. The increase in thresholds were less in C4 and C6 and minimal in C7 for all sensations. The analgesic effect lasted the longest in C5 (time × location mixed model P < 0.001 for all sensory tests). The time to rescue analgesia was significantly shorter with 0.75% ropivacaine (P = 0.02). The quantitative sensory findings showed no difference in intensity between the local anesthetics tested. A decrease in block intensity, with minimal changes in pain detection thresholds, was observed in the roots adjacent to C5, with the lowest block intensity in C7. A clinically relevant shorter duration was found with 0.75% ropivacaine compared to the other groups. Trial registration NCT 02691442.

Measuring future liver remnant function prior to hepatectomy may guide the indication for portal vein occlusion and avoid posthepatectomy liver failure: a prospective interventional study.

BACKGROUND: Estimation of the future liver remnant function (eFLRF) can avoid post-hepatectomy liver failure (PHLF). In a previous study, a cutoff value of 2.3%/min/m2 for eFLRF was a better predictor of PHLF than future liver remnant volume (FLRV%). In this prospective interventional study, investigating a management strategy aimed at avoiding PHLF, this cutoff value was the sole criterion assessing eligibility for hepatectomy, with or without portal vein occlusion (PVO). METHODS: In 100 consecutive patients, eFLRF was determined using the formula: eFLRF = FLRV% × total liver function (TLF). Group 1 (eFLRF >2.3%/min/m2) underwent hepatectomy without preoperative intervention. Group 2 (eFLRF <2.3%/min/m2) underwent PVO and re-evaluation of eFLRF at 4-6 weeks. Hepatectomy was performed if eFLRF had increased to >2.3%/min/m2, but was considered contraindicated if the value remained lower. RESULTS: In group 1 (n = 93), 1 patient developed grade B PHLF. In group 2 (n = 7) no PHLF was recorded. Postoperative recovery of TLF in patients with preoperative eFLRF <2.3%/min/m2 occurred more rapidly when PVO had been performed. CONCLUSION: A predefined cutoff for preoperatively calculated eFLRF can be used as a tool for selecting patients prior to hepatectomy, with or without PVO, thus avoiding PHLF and PHLF-related mortality.

Partial Nephrogenic Diabetes Insipidus in a Burned Patient Receiving Sevoflurane Sedation With an Anesthetic Conserving Device-A Case Report.

OBJECTIVE: To describe a case of partial nephrogenic diabetes insipidus in a burned patient after prolonged delivery of low inspired concentrations of sevoflurane via an Anesthetic Conserving Device. DATA SOURCES: Clinical observation. STUDY SELECTION: Case report. DATA EXTRACTION: Relevant clinical information. DATA SYNTHESIS: A 34-year-old man was admitted with burns covering 52% of his total body surface area. Mechanical ventilation was provided during sedation with continuous infusions of sufentanil and midazolam. Sedation became increasingly difficult, and in order to limit administration of IV agents, sevoflurane was added to the inspiratory gas flow. This was provided using an Anesthetic Conserving Device and continued for 8 days. The patient rapidly developed polyuria and hypernatremia with an inappropriate decrease in urinary osmolality. Administration of desmopressin resulted in only a modest effect on renal concentrating ability. After cessation of sevoflurane, all variables returned to normal within 5 days. The results of further investigations (cerebral computed tomographic scan, cerebral magnetic resonance imaging, and serum arginine vasopressin concentration) were compatible with a diagnosis of partial nephrogenic diabetes insipidus. The temporal sequence of clinical findings in relation to sevoflurane administration suggests that the sevoflurane was the probable underlying cause. CONCLUSIONS: Clinicians should be aware of the possibility of sevoflurane-induced diabetes insipidus not only during general anesthesia but also in the intensive care setting of sedation in critically ill patients. This is especially important in patients, such as those with severe burns, in whom preserved renal concentrating ability is important to ensure compensation for extrarenal fluid losses.

Comparison of gonadal radiation doses from CT enterography and small-bowel follow-through in pediatric patients.

OBJECTIVE. CT enterography is superior to small-bowel follow-through (SBFT) for diagnosis of inflammatory bowel disease (IBD). It is widely assumed that the radiation dose from CT enterography is greater than that from SBFT in the pediatric patient. This study was designed to compare gonadal doses from CT enterography and SBFT to verify the best imaging choice for IBD evaluation in children. This study also challenges the assumption that CT enterography imparts a higher radiation dose through comparison of calculated radiation doses from CT enterography and SBFT. MATERIALS AND METHODS. Patients 0-18 years old who underwent either CT enterography or SBFT over a 2-year period were included. The CT enterography group consisted of 39 boys and 51 girls, whereas the SBFT group consisted of 89 boys and 113 girls. CT enterography was performed at 120 kVp and approximately 132 mAs (range, 54-330 mAs) using weight-based protocols. SBFT used automated control of kilovoltage and tube current-exposure time product. Patient demographics and technical parameters were collected for CT enterography and SBFT, data were cross-paired between CT enterography and SBFT, and gonadal dose was calculated. RESULTS. Mean (± SD) CT enterography testis and ovarian doses were 0.93 ± 0.3 cGy (n = 39) and 0.64 ± 0.2 cGy (n = 51), respectively. Mean SBFT testis and ovarian doses were 2.3 ± 1.6 cGy (n = 89) and 1.49 ± 0.3 cGy (n = 113), respectively. Mean fluoroscopy time for SBFT was 2.6 ± 2 minutes. Gonadal dose for CT enterography was significantly lower than that for SBFT in boys and girls (p < 0.001). SBFT dose was lower in girls than boys (p < 0.001), whereas CT enterography dose was higher in boys than girls (p < 0.001). CONCLUSION. Gonadal dose for CT enterography was lower than that for SBFT for boys and girls of all sizes and age. Controlled exposure time made CT enterography dose more consistent, whereas the range of dose for SBFT was highly operator dependent and related to extent of disease. Thus, for IBD, CT enterography is preferred over SBFT for all children.

The Tritube: Facilitating Upper Airway Surgery With an Ultrathin Cuffed Airway Device.

The Tritube is a narrow-bore cuffed tracheal tube (outer diameter 4.4 mm and inner diameter ~2.4 mm) that permits effective alveolar gas exchange using flow-controlled ventilation. Constant gas flow delivers physiological minute volumes, within preset pressure limits, and applies suction to the airway during expiration. The technique has attracted interest for laryngotracheal microsurgery as it provides superior surgical exposure and avoids many of the complications associated with high-frequency jet ventilation. Cuff inflation protects the lower airway and produces a motionless operating field. We describe the structure of the device, discuss its benefits, and suggest how it should be used clinically.

An Effective Sanitizer for Fresh Produce Production: In Situ Plasma-Activated Water Treatment Inactivates Pathogenic Bacteria and Maintains the Quality of Cucurbit Fruit.

The effect of plasma-activated water (PAW) generated with a dielectric barrier discharge diffusor (DBDD) system on microbial load and organoleptic quality of cucamelons was investigated and compared to the established sanitizer, sodium hypochlorite (NaOCl). Pathogenic serotypes of Escherichia coli, Salmonella enterica, and Listeria monocytogenes were inoculated onto the surface of cucamelons (6.5 log CFU g-1) and into the wash water (6 log CFU mL-1). PAW treatment involved 2 min in situ with water activated at 1,500 Hz and 120 V and air as the feed gas; NaOCl treatment was a wash with 100 ppm total chlorine; control treatment was a wash with tap water. PAW treatment produced a 3-log CFU g-1 reduction of pathogens on the cucamelon surface without negatively impacting quality or shelf life. NaOCl treatment reduced the pathogenic bacteria on the cucamelon surface by 3 to 4 log CFU g-1; however, this treatment also reduced fruit shelf life and quality. Both systems reduced 6-log CFU mL-1 pathogens in the wash water to below detectable limits. The critical role of superoxide anion radical (·O2-) in the antimicrobial power of DBDD-PAW was demonstrated through a Tiron scavenger assay, and chemistry modeling confirmed that ·O2- generation readily occurs in DBDD-PAW generated with the employed settings. Modeling of the physical forces produced during plasma treatment showed that bacteria likely experience strong local electric fields and polarization. We hypothesize that these physical effects synergize with reactive chemical species to produce the acute antimicrobial activity seen with the in situ PAW system. IMPORTANCE Plasma-activated water (PAW) is an emerging sanitizer in the fresh food industry, where food safety must be achieved without a thermal kill step. Here, we demonstrate PAW generated in situ to be a competitive sanitizer technology, providing a significant reduction of pathogenic and spoilage microorganisms while maintaining the quality and shelf life of the produce item. Our experimental results are supported by modeling of the plasma chemistry and applied physical forces, which show that the system can generate highly reactive ·O2- and strong electric fields that combine to produce potent antimicrobial power. In situ PAW has promise in industrial applications as it requires only low power (12 W), tap water, and air. Moreover, it does not produce toxic by-products or hazardous effluent waste, making it a sustainable solution for fresh food safety.

Flow-controlled ventilation in moderate acute respiratory distress syndrome due to COVID-19: an open-label repeated-measures controlled trial.

BACKGROUND: Flow-controlled ventilation (FCV), a novel mode of mechanical ventilation characterised by constant flow during active expiration, may result in more efficient alveolar gas exchange, better lung recruitment and might be useful in limiting ventilator-induced lung injury. However, data regarding FCV in mechanically ventilated patients with acute lung injury or acute respiratory distress syndrome (ARDS) are scarce. OBJECTIVES: We hypothesised that the use of FCV is feasible and would improve oxygenation in moderate COVID-19 ARDS compared to conventional ventilation. DESIGN: Open-label repeated-measures controlled trial. SETTING: From February to April 2021, patients with moderate COVID-19 ARDS were recruited in a tertiary referral intensive care unit. PATIENTS: Patients with moderate ARDS (PaO2/FIO2 ratio 100-200 mmHg, SpO2 88-94% and PaO2 60-80 mmHg) were considered eligible. Exclusion criteria were: extremes of age (< 18 years, > 80 years), obesity (body mass index > 40 kg/m2), prone positioning at the time of intervention, mechanical ventilation for more than 10 days and extracorporeal membrane oxygenation. Eleven patients were recruited. INTERVENTION: Participants were ventilated in FCV mode for 30 min, and subsequently in volume-control mode (VCV) for 30 min. MAIN OUTCOME MEASURES: Feasibility of FCV to maintain oxygenation was assessed by the PaO2/FiO2 ratio (mmHg) as a primary outcome parameter. Secondary outcomes included ventilator parameters, PaCO2 and haemodynamic data. All adverse events were recorded. RESULTS: FCV was feasible in all patients and no adverse events were observed. There was no difference in the PaO2/FIO2 ratio after 30 min of ventilation in FCV mode (169 mmHg) compared to 30 min of ventilation in VCV mode subsequently (168 mmHg, 95% CI of pseudo-medians (- 10.5, 3.6), p = 0.56). The tidal volumes (p < 0.01) and minute ventilation were lower during FCV (p = 0.01) while PaCO2 was similar at the end of the 30-min ventilation periods (p = 0.31). Mean arterial pressure during FCV was comparable to baseline. CONCLUSIONS: Thirty minutes of FCV in patients with moderate COVID-19 ARDS receiving neuromuscular blocking agents resulted in similar oxygenation, compared to VCV. FCV was feasible and did not result in adverse events. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT04894214.

The Ventrain Device: A Future Role in Difficult Airway Algorithms?

The Ventrain is a small, manually operated, single-use, inspiratory flow-adjustable ventilation device that generates positive pressure during inspiration and, through a Bernoulli effect within the device, active suction during expiration. It was designed to provide emergency ventilation during airway obstruction via narrow-bore cannulae. The device has been used successfully in elective procedures lasting >1 hour. It remains to be seen if its theoretical advantages in "can't intubate, can't oxygenate" (CICO) scenarios translate to reliable clinical benefit and allow inclusion in future airway algorithms. We advocate for regular simulation training and the detailed reporting of clinical experience with this encouraging new tool.

Failed Awake Intubation for Critical Airway Obstruction Rescued With the Ventrain Device and an Arndt Exchange Catheter: A Case Report.

A 71-year-old man with advanced vocal cord carcinoma presented with severe airway obstruction. Therapeutic anticoagulation with enoxaparin complicated management. Failure of an oral awake bronchoscopic intubation was rescued by passing a guidewire through the working channel and threading an Arndt exchange catheter into the trachea under videoscopic vision. Ventilation with the Ventrain device lasting 40 minutes (15 L/min, inspiration/expiration 1:1, 15 breaths/min), during IV anesthesia with muscle paralysis, resulted in excellent blood gas values until placement of the tracheal cannula. This case report highlights the effectiveness of a novel ventilation technique that should be considered as back-up when bronchoscopic intubation fails.

Paradoxical fat embolism after uncemented total hip arthroplasty: a case report.

The authors report a paradoxical presentation of fat embolism after uncemented total hip arthroplasty. The patient presented vertigo and diplopia after surgery. Cerebral fat embolism was diagnosed by MRI. A patent foramen ovale was responsible for the venous to arterial circulation shunt. Treatment was conservative. Spontaneous and complete recovery occurred.

Neonates with hypoplastic left heart syndrome have ultrasound evidence of abnormal superior mesenteric artery perfusion before and after modified Norwood procedure.

OBJECTIVE: To a) describe superior mesenteric artery resistive index, as an estimate of perfusion, before and after modified Norwood; and b) assess incidence of diastolic flow reversal in the superior mesenteric artery before and after modified Norwood. DESIGN: Prospective observational trial. SETTING: Children's hospital pediatric intensive care unit. PATIENTS: Ten newborns with hypoplastic left heart syndrome. INTERVENTIONS: Ultrasound documentation of superior mesenteric artery diastolic flow direction and measurement of superior mesenteric artery resistive index 24-48 hrs before and 24-48 hrs after modified Norwood. MEASUREMENTS AND MAIN RESULTS: Seven males and three females were enrolled. There was no change between the superior mesenteric artery resistive index pre- vs. postoperatively-0.99 (95% confidence interval, 0.85, 1.12) vs. 1.07 (95% confidence interval, 1.0, 1.15) (p = .13). Incidence of retrograde diastolic blood flow in the superior mesenteric artery was not different pre- vs. postoperatively (70% vs. 50%, p = .41). No patients developed necrotizing enterocolitis and all survived to hospital discharge. CONCLUSIONS: Ultrasound measurements in neonates with hypoplastic left heart syndrome suggest that superior mesenteric artery perfusion, as measured by resistive index, is impaired. Superior mesenteric artery diastolic flow reversal is common before and immediately after modified Norwood.

The mutational spectrum of brachydactyly type C.

Growth/differentiation factor-5 (GDF5), also known as cartilage-derived morphogenetic protein-1 (CDMP-1), is a secreted signaling molecule that participates in skeletal morphogenesis. Heterozygous mutations in GDF5, which maps to human chromosome 20, occur in individuals with autosomal dominant brachydactyly type C (BDC). Here we show that BDC is locus homogeneous by reporting a GDF5 frameshift mutation segregating with the phenotype in a family whose trait was initially thought to map to human chromosome 12. We also describe heterozygous mutations in nine additional probands/families with BDC and show nonpenetrance in a mutation carrier. Finally, we show that mutant GDF5 polypeptides containing missense mutations in their active domains do not efficiently form disulfide-linked dimers when expressed in vitro. These data support the hypothesis that BDC results from functional haploinsufficiency for GDF5.

Wavelet decomposition of cardiovascular signals for baroreceptor function tests in pigs.

In this paper, the discrete wavelet transform (DWT) was applied to analyze the fluctuations in RR interval and systolic arterial pressure (SAP) recorded from eight alpha-chloralose anesthetized pigs. Our aim was to characterize the autonomic modulation before and after cardiac autonomic blockade and during baroreflex function tests. The instantaneous power of decomposed low-frequency (LF) and high-frequency (HF) components was used for a time-variant spectral analysis. Our results suggested that transient events and changes in autonomic modulation were detected with high temporal resolution. A nonlinear relationship between RR interval and SAP during pharmacologically induced changes in blood pressure was found, when the superimposed effect of respiratory sinus arrhythmia was removed. In addition, the baroslopes were nearly linear when both the LF and HF components were removed using DWT decomposition.

Unilateral Coexisting Intralobar and Extralobar Pulmonary Sequestrations.

Pulmonary sequestration is a focal area of nonfunctioning, dysplastic lung parenchyma that lacks communication with the normal tracheobronchial tree. It is supplied by the systemic arterial circulation and has two types, intralobar and extralobar, that can be differentiated from each other by the pleural covering and the venous drainage. Their coexistence is extremely rare. We report the imaging findings of a patient who had coexisting but completely separate intralobar and extralobar sequestrations at the left lower lung. We elucidated the complex vascular anatomy using three dimensional volume rendering and multiplanar reconstructions from a 64-detector helical CT scanner.

Radiographic detection of perflubron fluoromediastinum and fluororetroperitoneum 9 years after partial liquid ventilation.

A 17-year-old patient presented, after a motor vehicle collision, with right hip pain and unusual radiographs of the chest and pelvis. Multiple radiopacities obscured detail. These partly obscured and distracted attention from a right acetabular fracture. The etiology was persistent perflubron 9 years after partial liquid ventilation for acute respiratory distress syndrome. Persistence of perflubron beyond 138 days has not been previously reported. We review the imaging appearance of perflubron and the mechanism likely related to its distribution and persistence in this case, and emphasize the importance of obtaining clinical history and avoiding distraction when faced with unusual radiographic findings.

The accuracy of chest radiographs in the detection of congenital heart disease and in the diagnosis of specific congenital cardiac lesions.

BACKGROUND: Congenital heart disease (CHD) is a significant cause of morbidity and mortality in pediatric patients. Traditional teaching holds that specific types of CHD can be diagnosed on the chest radiograph (CXR) through pattern recognition. OBJECTIVE: To determine the accuracy of radiologists in detecting CHD on the CXR. MATERIALS AND METHODS: This study was a blinded retrospective review of chest radiographs from 281 patients (<12 years) by five pediatric radiologists from three institutions. Thirteen groups were evaluated that included 12 categories of CHD and a control group of patients without heart disease. Radiographs were assessed for heart size, heart and mediastinal shape and vascularity. Clinical information, angiography, echocardiograms and surgery were used as the gold standard for definitive diagnosis. RESULTS: The average accuracy of the five readers in distinguishing normal from CHD patients was 78% (range of 72% to 82%). The overall measure of accuracy in distinguishing specific congenital cardiac lesions among 13 groups of patients was 71% (range of 63% to 79%). CONCLUSION: CXR alone is not diagnostic of specific cardiac lesions, with a low accuracy of only 71%. We believe that less emphasis should be placed on the use of radiographs alone in diagnosing specific congenital cardiac lesions.

Unexpected diagnosis of superficial neurofibroma in a lesion with imaging features of a vascular malformation.

Plexiform neurofibroma is a pathognomonic, often disabling feature of neurofibromatosis type I. Although the target-like appearance of deep plexiform neurofibroma on T2-weighted MRI has been well-described, a second superficial form of plexiform neurofibroma has differing imaging features. We report a 15-year-old boy who presented with multiple cutaneous lesions exhibiting clinical and imaging characteristics of a venolymphatic malformation. These lesions were histologically proved to represent superficial plexiform neurofibromas. We wish to emphasize the unique MR findings of superficial plexiform neurofibromas; these findings are different from the imaging characteristics of the deep form and can be confused with a low-flow vascular malformation.