A method for sonographic counting of the lower vertebral bodies in newborns and infants.

PURPOSETo determine whether the lumbosacral junction of the vertebral column can be identified with sonography in newborns and infants and thus serve as a method for counting the lumbar and sacral vertebral bodies.METHODSIn 32 newborns and infants, the number of ossified vertebral bodies distal to the lumbosacral junction was counted with sonography and radiography.RESULTSSonographic and radiographic findings agreed in 29 of 32 examinations (91%).CONCLUSIONSThe lordotic transition at the lumbosacral junction can be identified with sonography in the majority of newborns and infants, allowing intraspinal structures to be related to a specific vertebral level.     

The influence of aging on the prognostic value of the revised cardiac risk index for postoperative cardiac complications in vascular surgery patients.

OBJECTIVE: The Lee-risk index [Lee-index] was developed to predict major adverse cardiac events [MACE]. However, age is not included as a risk factor. The aim was to assess the value of the Lee-index in vascular surgery patients among different age categories. METHODS: Of 2642 patients cardiovascular risk factors were noted to calculate the Lee-index. Patients were divided into four age categories; < or = 55 (n=396), 56-65 (n=650), 66-75 (n=1058) and > 75 years (n=538). Outcome measures were postoperative MACE (cardiac death, MI, coronary revascularization and heart failure). The performance of the Lee-index was determined using C-statistics within the four age groups. RESULTS: The incidence of MACE was 10.9%, for Lee-index 1, 2 and > or = 3; 6%, 13% and 20%, respectively. However, the prognostic value differed among age groups. The predictive value for MACE was highest among patients under 55 year (0.76 vs 0.62 of patients aged > 75). The prediction of MACE improved in elderly (aged > 75) after adjusting the Lee-index with age, revised risk of operation (low, low-intermediate, high-intermediate and high-risk procedures) and hypertension (0.62 to 0.69). CONCLUSION: The prognostic value of the Lee-index is reduced in elderly vascular surgery patients, adjustment with age, risk of surgical procedure, and hypertension improves the Lee-index significantly.     

Prognostic significance of declining ankle-brachial index values in patients with suspected or known peripheral arterial disease.

BACKGROUND: Peripheral arterial disease (PAD) is a risk factor for cardiovascular events. This study assessed the prognostic significance of repeated ankle-brachial index (ABI) measurements at rest and after exercise in patients with PAD receiving conservative treatment. METHODS: In a cohort study of 606 patients (mean age 62+/-12 years, 68% male), ABI at rest and after exercise was measured at baseline and after 1 year. Patients with reductions in ABI were divided into three equally-sized groups (minor, intermediate and major reductions) and were compared to patients without reductions. During a mean follow-up of 5+/-3 years, all-cause mortality, cardiac events, stroke and progression to kidney failure were noted. RESULTS: Death was recorded in 83 patients (14%) of which 49% were due to cardiac causes. Non-fatal myocardial infarction occurred in 38 patients (6%), stroke in 46 (8%) and progression to kidney failure in 35 (6%). By multivariate analysis, patients with major declines in resting (>20%) and post-exercise (>30%) ABI were at increased risk of all-cause mortality (HR: 3.3, 95% CI: 1.5-7.2, HR: 3.0, 95% CI: 1.4-6.4, respectively), cardiac events (HR: 3.1, 95% CI: 1.3-7.2, HR: 2.4, 95% CI: 1.1-5.6, respectively), stroke (HR: 4.2, 95% CI: 1.6-10.4, HR: 3.9, 95% CI: 1.4-10.2, respectively) and kidney failure (HR: 2.7, 95% CI: 1.1-7.5, HR: 6.9, 95% CI: 1.5-31.5, respectively), compared to patients with no declines in ABI. CONCLUSIONS: This study shows that major 1-year declines in resting and post-exercise ABI are associated with all-cause mortality, cardiac events, stroke and kidney failure in patients with PAD.     

Early one-stage orthotopic jejunal pedicle-graft interposition in long-gap esophageal atresia

Since 1988, four children with long-gap esophageal atresia have undergone one-stage orthotopic jejunal pedicle-graft interposition at the age of 2 to 3 months. Obtaining enough jejunal length was no problem and major early complications did not occur. In one patient stenosis of the distal anastomosis was problematic and required corrective surgery. None of the patients demonstrated jejunitis as a result of gastroesophageal reflux. With follow-up periods of 12, 27, 46, and 60 months, all patients are doing well. It is concluded that the jejunum is a better esophageal substitute than is generally appreciated.     

Laparoscopy in infants and children: a prospective study on feasibility and the impact on routine surgery

BACKGROUND/PURPOSE: The feasibility of laparoscopy in children and its impact on routine pediatric surgery are not well established. The purpose of this study was to determine the role of laparoscopy in a university department of pediatric surgery. METHODS: All children undergoing laparoscopy during the period of 1 year were included in a prospective trial. Data on patients, the operation, technical problems, intraoperative events, and the postoperative course were documented using standardized questionnaires. All patients underwent at least 1 follow-up assessment 2 weeks after the operation. All conventional abdominal operations performed during the same period were analyzed for comparison purposes. RESULTS: Of 244 abdominal operations performed during the study period, 147 (60.2%) were laparoscopies. One hundred twenty-three (83.7%) of these included a laparoscopic operation, and 24 (16.3%) were diagnostic procedures. Of 26 types of laparoscopic operations 3 were performed more than 15 times (fundoplication, appendectomy, pyloromyotomy), and 9 types were performed once. Problems with instruments and devices led to a mean time loss of 15.1 minutes in 15.6% of the procedures. The conversion rate was 10.1% mainly because of complicated appendicitis. Fifty-six children (38.1%) weighed less than 10 kg, and the conversion rate did not correlate with the body weight. There was 1 (0.07%) intraoperative event. A small bowel perforation was identified immediately and resolved with an uneventful course. Postoperative complications included an incisional hernia in 3 children and an incisional leakage of liquor in 1 child with a ventriculoperitoneal drain. There was a reprolaps after laparoscopic correction of an ileostomy in 1 child and fever in another. In 3 newborns the diagnosis was missed during laparoscopy and had to be established by laparotomy later with an uneventful course. Primary conventional operations were mainly restricted to bowel resection and anastomosis performed in 52 of 97 laparotomies. CONCLUSIONS: The authors showed that 60% of abdominal operations in children can be performed via laparoscopy. Most types of laparoscopic operations are not performed frequently, but the feasibility of the technique in routine use is excellent. However, the performance of instruments should be improved further, and laparoscopy for establishing the diagnosis in newborns remains difficult.     

Hybrid measurement of respiratory aerosol reveals a dominant coarse fraction resulting from speech that remains airborne for minutes

Accurate measurements of the size and quantity of aerosols generated by various human activities in different environments are required for efficacious mitigation strategies and accurate modeling of respiratory disease transmission. Previous studies of speech droplets, using standard aerosol instrumentation, reported very few particles larger than 5 μm. This starkly contrasts with the abundance of such particles seen in both historical slide deposition measurements and more recent light scattering observations. We have reconciled this discrepancy by developing an alternative experimental approach that addresses complications arising from nucleated condensation. Measurements reveal that a large volume fraction of speech-generated aerosol has diameters in the 5- to 20-μm range, making them sufficiently small to remain airborne for minutes, not hours. This coarse aerosol is too large to penetrate the lower respiratory tract directly, and its relevance to disease transmission is consistent with the vast majority of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections initiating in the upper respiratory tract. Our measurements suggest that in the absence of symptoms such as coughing or sneezing, the importance of speech-generated aerosol in the transmission of respiratory diseases is far greater than generally recognized.

Respiratory tract infections are caused by a wide range of pathogenic organisms (1), including a large array of respiratory viruses, such as influenza virus, rhinovirus, measles virus, respiratory syncytial virus, adenovirus, and most recently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In all these diseases, person-to-person spread involves respiratory droplets, which originate from the mucus layer that covers the epithelium of the respiratory tract or from oral fluid present in the mouth, mostly as saliva. Thus, characterizing respiratory droplets is essential to understanding respiratory pathogen transmission and will inform effective public health policies to curb infections. Four mechanisms for droplet generation are generally considered: breathing, speaking (singing, laughing, etc.), coughing, and sneezing (2). Considering the well-recognized importance of asymptomatic transmission of SARS-CoV-2 (3), our study focuses on the first two of these mechanisms.As highlighted by Wells (4) and Duguid (2) nearly a century ago, the vast majority of respiratory droplets are smaller than ca. 100-μm diameter and fully dehydrate once entering the atmosphere. These desiccated droplets can remain airborne for minutes to hours before landing on solid surfaces. If generated by a person infected by a respiratory virus, they will contain virions that can remain viable and infectious for many hours (5, 6). Upon inhalation, airborne particles can reach different parts of the respiratory tract depending on their size: coarse aerosols with diameter D ≳ 5 μm (7) deposit in the upper respiratory tract (URT), and fine aerosols with D < 5 μm can penetrate deep into the lower respiratory tract (LRT). Many viral pathogens, including SARS-CoV-2, influenza, rhinovirus, and measles virus, can infect both URT and LRT epithelia (1, 8, 9), with URT infections typically associated with mild initial symptoms and LRT infections possibly resulting in life-threatening pneumonia (1, 10–13). Direct infection of the LRT, before the adaptive immune system has been triggered by vaccination or a preceding URT infection, presents a greater risk.An URT infection also can expand into the LRT through microaspiration of oropharyngeal fluids (14, 15). The extent to which inhalation of self-generated URT cough, speech, or sneeze aerosols may contribute to this migration remains unknown. However, it has been argued that this pathway could be significant because an infected carrier is invariably at the center of their own speech aerosol cloud, which results in strongly elevated exposure (16). The risk of migration from the URT to the LRT rises with the viral load and the viability of the virus, which peak around and just prior to the onset of symptoms, respectively (17, 18). For the original Wuhan strain of the SARS-CoV-2 virus, the onset of symptoms occurs about 5 days after the initial infection (17, 19), but it occurs somewhat earlier for the more infectious delta and omicron variants (20).To evaluate the risk of LRT infection, it is important to know the size distribution of particles generated by various respiratory activities. For talking, coughing, and sneezing, studies historically relied on slide sampling techniques of increasing sophistication, followed by microscope observation (2, 21, 22). Droplets generated by breathing or vowel sounds are numerous but very small (≲2 μm) and thus more difficult to evaluate with those classical methods. Instead, such small droplets are now commonly quantified by aerosol detection equipment, such as optical particle sizers (OPSs), based on light scattering (22, 23); aerodynamic particle sizers (APSs), based on the time-of-flight measurement in an accelerating flow field (24); and scanning mobility particle sizers that derive a particle’s size from its mobility in an electric field and are best suited for very small sizes (≲1 μm) (25, 26). APS instruments are less efficient at detecting medium-sized liquid particles, and undercounts as high as 75% for 10-μm droplets have been reported (27).There is some confusion in the literature about the hydration state of reported sizes of respiratory aerosol particles, which shrink by a factor of γ upon evaporation of their aqueous content, thus by a factor of γ³ in volume. After full dehydration, a particle’s radius is determined by its amount of nonvolatile matter. Estimates for γ vary substantially: Nicas et al. (28) proposed γ = 2 for breath particles, based on data extracted from breath condensate by Effros et al. (29) that indicated a high fraction (ca. 8% wt/vol) of glycoproteins, presumably mucins. Holmgren et al. (30) reported γ = 2.4 for breath particles when the relative humidity (RH) is reduced from 99.5% in the small airways to 75%. Bagheri et al. (26) observed γ = 4.5 for singing particles in a diffusion dryer or γ = 4 for large saliva droplets observed directly by microscope imaging. Some of those measurements were conducted directly at the mouth opening, observing the hydrated state using light scattering or holographic imaging techniques (26, 31). Clearly, the concentration of pathogens in dehydrated particles scales with γ³ relative to the originating airway lining fluid (ALF) or saliva. However, the high uncertainty in the applicable γ value, which is frequently not even reported, prevents accurate estimates of airborne virus concentrations.Recently, we and others demonstrated that speech particles can be readily observed by simple video recordings of light scattering by these particles (32–35). Such recordings not only present a visually compelling warning to the public but also provide opportunities to monitor particles before, during, and after dehydration. Those light scattering measurements focused on particles larger than a few microns due to technical sensitivity issues. The intensity of scattered light scales with the square of a particle’s diameter, causing a dynamic range problem and rendering it more challenging to observe the smallest particles, especially in the presence of larger particles. Inexpensive, fast consumer cameras typically use 10- to 12-bit analog-to-digital converters (ADCs), thereby limiting dynamic range; while detectors with an increased ADC range are available, their speed is often insufficient for high-speed recording.Here, we aim to evaluate the entire range of speech droplet sizes produced during different breathing and speaking protocols. To do so, we combined video-recorded light scattering and an OPS to evaluate droplets from 0.3 to 100 μm. Our data show a continuous spectrum that lacks previously reported gaps in the size distribution (36). Our measurements confirm that the gravitational settling rate for dehydrated particles larger than 5 μm steeply increases with size, but considering the high numbers, volumes, and airborne lifetimes of those particles, they are likely to be a dominant factor in transmission of disease.     

Assessment of left ventricular mechanical dyssynchrony by phase analysis of ECG-gated SPECT myocardial perfusion imaging

Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. However, at least 30% of patients selected for CRT by use of traditional criteria (New York Heart Association class III or IV, depressed left ventricular [LV] ejection fraction, and prolonged QRS duration) do not respond to CRT. Recent studies with tissue Doppler imaging have shown that the presence of LV dyssynchrony is an important predictor of response to CRT. Phase analysis has been developed to allow assessment of LV dyssynchrony by gated single photon emission computed tomography myocardial perfusion imaging. This technique uses Fourier harmonic functions to approximate regional wall thickness changes over the cardiac cycle and to calculate the regional onset-of-mechanical contraction phase. Once the onset-of-mechanical contraction phases are obtained 3-dimensionally over the left ventricle, a phase distribution map is formed that represents the degree of LV dyssynchrony. This technique has been compared with other methods of measuring LV dyssynchrony and shown promising results in clinical evaluations. In this review the phase analysis methodology is described, and its up-to-date validations are summarized.