Reusable laryngoscope blades: a more eco-responsible and cost-effective alternative.

INTRODUCTION: Consumption of single-use medical devices has increased considerably, contributing to the excessive wastage produced during surgical procedures. The present study aimed to describe a methodology to assess the transition from single-use blades (SUB) to reusable laryngoscope blades (RUB) and to assess the ecological and economic impact of the switch. METHODS: The ecological analysis was based on the life cycle assessment method. Based on 30 operating rooms in a single tertiary university hospital, the economic analysis compared the usual SUB supplier with four RUB suppliers considering different costs: blade purchasing and depreciation, reprocessing, logistics and waste management. RESULTS: In 2021, 17,200 intubations were performed requiring about 147 RUBs. Switching from SUB to RUB led to an annual saving of 26.5 tons of CO2eq (global warming impact), equivalent to 120 000 km by car. It avoids the extraction of 6.6 tons Oileq (petroleum) and 579 kg of copper (mineral resources) per year. This action also leads to a land occupation reduction of 626 m2 per year and water savings of 221.6 m3 per year. The average cost per intubation varies from 3.16 [3.15-3.16] for SUB to 2.81 [2.77-2.85] for RUB, representing an average saving of 0.35 per intubation leading to 5783.50 annual gain [5074.00-6192.00]. RUB are preferable from 3 and 86 uses from an ecological and economic viewpoint, respectively. CONCLUSION: In a model of 17,200 intubations /year, switching SUD to RUB would save 26.5 tons of CO2eq and 6.6 tons of Oileq with 5783.50 annual gain. RUBs are ecologically and cost-effective after 3 and 86 uses, respectively.

Ecoresponsible actions in operating rooms: A health ecological and economic evaluation.

BACKGROUND: In the current context of climate change, actions must be taken to improve the hospital's ecological footprint, particularly in the operating room, which is a major consumer of medical devices. METHODS: This prospective pilot study assessed the ecological and economic impacts of sustainable actions targeting medical devices designed by a multidisciplinary working group and implemented in the 24 operating rooms of a University Hospital over one year. The ecological analysis was based on the life cycle assessment method and categorized in seven impacts. The economic impact was assessed by a micro-costing analysis and divided in four main expense items: human and material resources, logistics, and waste management. RESULTS: In total, 13 actions were implemented with the aim of reducing waste volume, improving waste sorting, and increasing eco-responsible purchases. In one year, these 13 actions allowed avoiding the emission of 203 tons eq CO2. The environmental and human toxicity benefits were 707.8 and 156.2 tons of 1.4 dichlorobenzene, respectively. Concerning non-renewable resources, these actions avoided the extraction of 9 tons of oil (petroleum) and 610 kg of copper per year. These actions led to a land occupation reduction of 1071.3 m2year and to water saving of 552 m3. From the economic side, the implementation of these actions brought a gain of €3747.9 for the first year and of €5188.2 for the following years. CONCLUSION: The integration of sustainable measures in operating rooms leads to important ecological benefits and also generating savings. This more eco-responsible approach should be considered in all healthcare establishments that generate a significant annual volume of waste.

The use of tissue-engineered skin to demonstrate the negative effect of CXCL5 on epidermal ultraviolet radiation-induced cyclobutane pyrimidine dimer repair efficiency.

BACKGROUND: Ultraviolet radiation (UVR) is responsible for keratinocyte cancers through the induction of mutagenic cyclobutane pyrimidine dimers (CPDs). Many factors influence CPD repair in epidermal keratinocytes, and a better understanding of those factors might lead to prevention strategies against skin cancer. OBJECTIVES: To evaluate the impact of dermal components on epidermal CPD repair efficiency and to investigate potential factors responsible for the dermal-epidermal crosstalk modulating UVR-induced DNA damage repair in keratinocytes. METHODS: A model of self-assembled tissue-engineered skin containing human primary keratinocytes and fibroblasts was used in this study. RESULTS: We showed that CPD repair in keratinocytes is positively influenced by the presence of a dermis. We investigated the secretome and found that the cytokine CXCL5 is virtually absent from the culture medium of reconstructed skin, compared with media from fibroblasts and keratinocytes alone. By modulating CXCL5 levels in culture media of keratinocytes, we have shown that CXCL5 is an inhibitor of CPD repair. CONCLUSIONS: This work outlines the impact of the secreted dermal components on epidermal UVR-induced DNA damage repair and sheds light on a novel role of CXCL5 in CPD repair.

Autologous bilayered self-assembled skin substitutes (SASSs) as permanent grafts: a case series of 14 severely burned patients indicating clinical effectiveness.

Split-thickness skin autografts (AGs) are the standard surgical treatment for severe burn injuries. However, the treatment of patients with substantial skin loss is limited by the availability of donor sites for skin harvesting. As an alternative to skin autografts, our research group developed autologous self-assembled skin substitutes (SASSs), allowing the replacement of both dermis and epidermis in a single surgical procedure. The aim of the study was to assess the clinical outcome of the SASSs as a permanent coverage for full-thickness burn wounds. Patients were recruited through the Health Canada's Special Access Program. SASSs were grafted on debrided full-thickness wounds according to similar protocols used for AGs. The graft-take and the persistence of the SASS epithelium over time were evaluated. 14 patients received surgical care with SASSs. The mean percentage of the SASS graft-take was 98 % (standard deviation = 5) at 5 to 7 d after surgery. SASS integrity persisted over time (average follow-up time: 3.2 years), without noticeable deficiency in epidermal regeneration. Assessment of scar quality (skin elasticity, erythema, thickness) was performed on a subset of patients. Non-homogeneous pigmentation was noticed in several patients. These results indicated that the SASS allowed the successful coverage of full-thickness burns given its high graft-take, aesthetic outcome equivalent to autografting and the promotion of long-term tissue regeneration. When skin donor sites are in short supply, SASSs could be a valuable alternative to treat patients with full-thickness burns covering more than 50 % of their total body surface area.

Self-assembled human osseous cell sheets as living biopapers for the laser-assisted bioprinting of human endothelial cells.

A major challenge during the engineering of voluminous bone tissues is to maintain cell viability in the central regions of the construct. In vitro prevascularization of bone substitutes relying on endothelial cell bioprinting has the potential to resolve this issue and to replicate the native bone microvasculature. Laser-assisted bioprinting (LAB) commonly uses biological layers of hydrogel, called 'biopapers', to support patterns of printed cells and constitute the basic units of the construct. The self-assembly approach of tissue engineering allows the production of biomimetic cell-derived bone extracellular matrix including living cells. We hypothesized that self-assembled osseous sheets can serve as living biopapers to support the LAB of human endothelial cells and thus guide tubule-like structure formation. Human umbilical vein endothelial cells were bioprinted on the surface of the biopapers following a predefined pattern of lines. The osseous biopapers showed relevant matrix mineralization and pro-angiogenic hallmarks. Our results revealed that formation of tubule-like structures was favored when the cellular orientation within the biopaper was parallel to the printed lines. Altogether, we validated that human osseous cell sheets can be used as biopapers for LAB, allowing the production of human prevascularized cell-based osseous constructs that can be relevant for autologous bone repair applications.

MRI of the cervical spinal cord predicts respiratory dysfunction in ALS.

For patients with amyotrophic lateral sclerosis (ALS), the primary therapeutic goal is to minimize morbidity. Non-invasive ventilation improves survival. We aim to assess whether Magnetic Resonance Imaging (MRI) of the cervical spinal cord predicts the progression of respiratory disorders in ALS. Brain and spinal MRI was repeatedly performed in the SOD1G86R mouse model, in 40 patients and in healthy controls. Atrophy, iron overload, white matter diffusivity and neuronal loss were assessed. In Superoxide Dismutase-1 (SOD1) mice, iron accumulation appeared in the cervical spinal cord at symptom onset but disappeared with disease progression (after the onset of atrophy). In ALS patients, the volumes of the motor cortex and the medulla oblongata were already abnormally low at the time of diagnosis. Baseline diffusivity in the internal capsule was predictive of functional handicap. The decrease in cervical spinal cord volume from diagnosis to 3 months was predictive of the change in slow vital capacity at 12 months. MRI revealed marked abnormalities at the time of ALS diagnosis. Early atrophy of the cervical spinal cord may predict the progression of respiratory disorders, and so may be of value in patient care and as a primary endpoint in pilot neuroprotection studies.

Hippocampal Deformations and Entorhinal Cortex Atrophy as an Anatomical Signature of Long-Term Cognitive Impairment: from the MCAO Rat Model to the Stroke Patient.

Stroke patients have an elevated risk of developing long-term cognitive disorders or dementia. The latter is often associated with atrophy of the medial temporal lobe. However, it is not clear whether hippocampal and entorhinal cortex atrophy is the sole predictor of long-term post-stroke dementia. We hypothesized that hippocampal deformation (rather than atrophy) is a predictive marker of long-term post-stroke dementia on a rat model and tested this hypothesis in a prospective cohort of stroke patients.Male Wistar rats were subjected to transient middle cerebral artery occlusion and assessed 6 months later. Ninety initially dementia-free patients having suffered a first-ever ischemic stroke were prospectively included in a clinical study. In the rat model, significant impairments in hippocampus-dependent memories were observed. MRI studies did not reveal significant atrophy of the hippocampus volume, but significant deformations were indeed observed-particularly on the ipsilateral side. There, the neuronal surface area was significantly lower in ischemic rats and was associated with a lower tissue density and a markedly thinner entorhinal cortex. At 6 months post-stroke, 49 of the 90 patients displayed cognitive impairment (males 55.10%). Shape analysis revealed marked deformations of their left hippocampus, a significantly lower entorhinal cortex surface area, and a wider rhinal sulcus but no hippocampal atrophy. Hence, hippocampal deformations and entorhinal cortex atrophy were associated with long-term impaired cognitive abilities in a stroke rat model and in stroke patients. When combined with existing biomarkers, these markers might constitute sensitive new tools for the early prediction of post-stroke dementia.

The topography of cortical microbleeds in frontotemporal lobar degeneration: a post-mortem 7.0-tesla magnetic resonance study.

INTRODUCTION: Cerebrovascular lesions are rare in frontotemporal lobar degeneration (FTLD), in contrast to other neurodegenerative diseases. Cortical microbleeds (CoMBs) are frequent in Alzheimer's disease, in particular in cases associated with cerebral amyloid angiopathy. The present study investigates the gyral topographic distribution of CoMBs in post-mortem FTLD brains with 7.0-tesla magnetic resonance imaging. MATERIAL AND METHODS: The distribution of CoMBs in 11 post-mortem FTLD brains and in 12 control brains was compared on T2*-GRE MRI of six coronal sections of a cerebral hemisphere. The mean values of CoMBs were determined in twenty-two different gyri. The findings were correlated to those separately observed on neuropathological examination. RESULTS: As a whole there was a trend of more CoMBs in the prefrontal section of FTLD as well as of the control brains. CoMBs were significantly increased in the superior frontal gyrus and the insular cortex (p ≤ 0.001) and also in the inferior frontal gyrus and the superior temporal gyrus (p ≤ 0.01). CONCLUSIONS: CoMBs in FTLD are only increased in the regions mainly affected by the neurodegenerative lesions. They probably do not reflect additional cerebrovascular disease.

Topography of Cortical Microbleeds in Alzheimer's Disease with and without Cerebral Amyloid Angiopathy: A Post-Mortem 7.0-Tesla MRI Study.

Cortical microbleeds (CMBs) detected on T2*-weighted gradient-echo (GRE) magnetic resonance imaging (MRI) are considered as a possible hallmark of cerebral amyloid angiopathy (CAA). The present post-mortem 7.0-tesla MRI study investigates whether topographic differences exist in Alzheimer's brains without (AD) and with CAA (AD-CAA). The distribution of CMBs in thirty-two post-mortem brains, consisting of 12 AD, 8 AD-CAA and 12 controls, was mutually compared on T2*-GRE MRI of six coronal sections of a cerebral hemisphere. The mean numbers of CMBs were determined in twenty-two different gyri. As a whole there was a trend of more CMBs on GRE MRI in the prefrontal section of the AD, the AD-CAA as well as of the control brains. Compared to controls AD brains had significantly more CMBs in the superior frontal, the inferior temporal, the rectus and the cinguli gyrus, and in the insular cortex. In AD-CAA brains CMBs were increased in all gyri with exception of the medial parietal gyrus and the hippocampus. AD-CAA brains showed a highly significant increase of CMBs in the inferior parietal gyrus (p value: 0.001) and a significant increase in the precuneus and the cuneus (p value: 0.01) compared to the AD brains. The differences in topographic distribution of CMBs between AD and AD-CAA brains should be further investigated on MRI in clinically suspected patients.

EPR and electrochemical quantification of oxygen using newly synthesized para-silylated triarylmethyl radicals.

Novel silylated triarylmethyl (TAM) radicals based on TAM core CT-03 and their electron paramagnetic resonance (EPR) spectra are evaluated as a function of oxygen concentration. Combination of peak-to-peak linewidth of the EPR signal and electrochemical determination allows designing a method for oxygen quantification in phosphate buffer, dimethylsulfoxide, and dichloromethane, which can be extended to other solvents.

Post-mortem 7.0-tesla magnetic resonance study of cortical microinfarcts in neurodegenerative diseases and vascular dementia with neuropathological correlates.

BACKGROUND: Until recently cortical microinfarcts (CMIs) were considered as the invisible lesions in clinical-radiological correlation studies that rely on conventional structural magnetic resonance imaging. The present study investigates the presence of CMIs on 7.0-T magnetic resonance imaging (MRI) in post-mortem brains with different neurodegenerative and cerebrovascular diseases. MATERIALS AND METHODS: One hundred-seventy five post-mortem brains, composed of 37 with pure Alzheimer's disease (AD), 12 with AD associated to cerebral amyloid angiopathy (AD-CAA), 38 with frontotemporal lobar degeneration, 12 with amyotrophic lateral sclerosis, 16 with Lewy body disease (LBD), 21 with progressive supranuclear palsy, 18 with vascular dementia (VaD) and 21 controls were examined. According to their size several types of CMIs were detected on 3 coronal sections of a cerebral hemisphere with 7.0-T MRI and compared to the mean CMI load observed on histological examination of one standard separate coronal section of a cerebral hemisphere at the level of the mamillary body. RESULTS: Overall CMIs were significantly prevalent in those brains with neurodegenerative and cerebrovascular diseases associated to CAA compared to those without CAA. VaD, AD-CAA and LBD brains had significantly more CMIs compared to the controls. While all types of CMIs were increased in VaD and AD-CAA brains, a predominance of the smallest ones was observed in the LBD brains. CONCLUSIONS: The present study shows that 7.0-T MRI allows the detection of several types of MICs and their contribution to the cognitive decline in different neurodegenerative and cerebrovascular diseases.

Iron deposits in post-mortem brains of patients with neurodegenerative and cerebrovascular diseases: a semi-quantitative 7.0 T magnetic resonance imaging study.

BACKGROUND AND PURPOSE: Accumulation of iron (Fe) is often detected in brains of people suffering from neurodegenerative diseases. However, no studies have compared the Fe load between these disease entities. The present study investigates by T2*-weighted gradient-echo 7.0 T magnetic resonance imaging (MRI) the Fe content in post-mortem brains with different neurodegenerative and cerebrovascular diseases. METHODS: One hundred and fifty-two post-mortem brains, composed of 46 with Alzheimer's disease (AD), 37 with frontotemporal lobar degeneration (FTLD), 11 with amyotrophic lateral sclerosis, 13 with Lewy body disease, 14 with progressive supranuclear palsy, 16 with vascular dementia (VaD) and 15 controls without a brain disease, were examined. The Fe load was determined semi-quantitatively on T2*-weighted MRI serial brain sections in the claustrum, caudate nucleus, putamen, globus pallidus, thalamus, subthalamic nucleus, hippocampus, mamillary body, lateral geniculate body, red nucleus, substantia nigra and dentate nucleus. The disease diagnosis was made on subsequent neuropathological examination. RESULTS: The Fe load was significantly increased in the claustrum, caudate nucleus and putamen of FTLD brains and to a lesser degree in the globus pallidus, thalamus and subthalamic nucleus. In the other neurodegenerative diseases no Fe accumulation was observed, except for a mild increase in the caudate nucleus of AD brains. In VaD brains no Fe increase was detected. CONCLUSIONS: Only FTLD displays a significant Fe load, suggesting that impaired Fe homeostasis plays an important role in the pathogenesis of this heterogeneous disease entity.

Superficial siderosis of the central nervous system: a post-mortem 7.0-tesla magnetic resonance imaging study with neuropathological correlates.

BACKGROUND: Superficial siderosis (SS) is a rare finding on T2*-weighted magnetic resonance imaging (MRI), regarded as a radiological marker of cerebral amyloid angiopathy (CAA). The present study investigates with 7.0-tesla MRI the prevalence of SS and its underlying pathological substrate in a consecutive series of post-mortem brains of elderly patients with various neurodegenerative and cerebrovascular lesions. MATERIALS AND METHODS: The prevalence of SS and associated lesions was screened using 7.0-tesla MRI and their neuropathological correlates in 120 post-mortem brains of patients with various neurodegenerative and cerebrovascular diseases. RESULTS: Eighty-three separate zones of SS were detected in 45 brains (37.5%), including 25 areas of disseminated SS (dSS) and 58 areas of focal SS (fSS), restricted to less than 3 sulci. dSS was spatially related to sequels of 14 lobar haematomas and 11 cerebral infarcts, while fSS was connected to 19 microbleeds and 39 micro-infarcts (p < 0.001). Comparison of the 15 CAA to the 30 non-CAA brains showed that dSS was due to an old lobar haematoma in 53% of the former group compared to 3% of the latter group (p = 0.003). fSS was due to a microbleed in 7% of the CAA brains and to 40% of the non-CAA brains (p = 0.03). CONCLUSIONS: SS is associated with both haemorrhagic and ischaemic underlying lesions. It is frequently observed on T2*-weighted 7.0-tesla MRI, and two types of SS may be described. Clinicians should keep in mind that SS may be found in other settings than CAA.

Detection of microbleeds in post-mortem brains of patients with frontotemporal lobar degeneration: a 7.0-Tesla magnetic resonance imaging study with neuropathological correlates.

BACKGROUND: Microbleeds (MBs) are frequently detected in brains of patients with Alzheimer dementia and rare in those with frontotemporal lobar degeneration (FTLD). This study investigates for the first time the topographic distribution of MBs on a T2*-weighted gradient-echo 7.0-T magnetic resonance imaging (MRI) in post-mortem FTLD brains. PATIENTS AND METHODS: The neuropathological and MRI findings in 12 FTLD brains were compared with eight age-matched controls. The presence of cerebrovascular lesions was evaluated on a coronal section of a cerebral hemisphere at the level of the mamillary body and on a horizontal section through pons and cerebellum. On MRI, the distribution and the number of cortical focal signal intensity losses, representing MBs, were assessed on coronal sections at the frontal, the central and the occipital level of a cerebral hemisphere. RESULTS: Overall, cerebrovascular lesions were rare. Only white matter damage was significantly more severe in FTLD brains compared with controls (P = 0.03). On MRI, MBs were only significantly prevalent in the deep cortical layers (P < 0.01) and borderline increased in the middle cortical layers (P = 0.07) of the frontal section. CONCLUSIONS: Cerebrovascular lesions are rare in FTLD. The white matter damage has to be considered as part of the neurodegenerative process. MBs prevail in the frontal regions with the most severe neuronal damage and probably represent associated disruption of the blood-brain barrier.

Comparison of 7.0-T T2*-magnetic resonance imaging of cerebral bleeds in post-mortem brain sections of Alzheimer patients with their neuropathological correlates.

BACKGROUND: In view of the increasing recognition of cerebral microbleeds (MCBs) with MRI, there is a need to validate their detection in post-mortem brains in patients with cerebrovascular diseases and dementia. MATERIALS AND METHODS: Out of 20 post-mortem brains of patients with Alzheimer dementia and with different cerebrovascular lesions, 45 large sections of the cerebral hemispheres, brainstem and cerebellum were submitted to a 7.0-T T2*-weighted MRI, and afterwards compared to the histological detection of haematomas, MCBs and mini-bleeds (MNBs). RESULTS: The sensitivity, specificity, predictive positive value and predictive negative value of the T2* imaging to detect MCBs and MNBs were excellent for those in the cortico-subcortical regions. There was a significant overestimation of MNBs in the striatum due to iron deposits unrelated to old haemorrhages. Also in the deep white matter, 42% of MNBs were not detected, while 31% of T2* hyposignals were not due to MNBs but to vessels filled with post-mortem thrombi. CONCLUSIONS: When evaluating the 'bleeding load' with 7.0-T T2*-weighted MRI in post-mortem brain sections of patients with dementia and vascular risk factors, only quantification of small cerebral bleeds in the cortico-subcortical regions is reliable.

[MR imaging of coronary arteries: noncontrast free-breathing whole heart acquisition with ultrafast 3D balanced gradient-echo technique]. / Imagerie par résonance magnétique des artères coronaires: acquisition "coeur entier", en respiration libre, sans injection d'agent de contraste et utilisant la séquence 3D en écho de gradient balancé ultrarapide.

The 3D balanced gradient-echo technique is described along with th eimaging protocol for MR imaging of th ecoronary arteries. A 3D volume with spatial resolution of 0.6 x 0.6 x 0.75 mm composed of 140 slices covering the whole heart is acquired over 10 minutes. The main advantage of this whole heart technique is the possibility to image the coronary arteries along their entire course in a single acquisition. Selection of the navigator positions, timing of image acquisition and its duration through the R-R interval are the main factors requiring optimization.

[Contrast enhanced MR angiography: evolving towards whole-body real time acquisitions]. / Angiographie par résonance magnétique avec injection de produit de contraste: évolution vers le corps entier et le temps réel.

MRA includes all techniques used to depict vessels with MR. Gadolinium contrast injection combined with gradient echo sequences is the technique of choice for vascular imaging. Technical advances now allow faster acquisitions. The purpose of this article is to present two main advances with MRA: whole-body MRA and dynamic 3D MRA. Technical considerations, acquisition techniques, advantages and pitfalls based on our experience with a 1.5T MR unit will be discussed in order to promote their use in routine clinical practice.

Skin substitutes and wound healing.

Medical science has vastly improved on the means and methods available for the treatment of wounds in the clinic. The production and use of various types of skin substitutes has led to dramatic improvements in the odds of survival for severely burned patients, but they have also shown promise for many other applications, including cases involving chronic wounds that are not life threatening. Nowadays, more than 20 products are commercially available, more are undergoing clinical trials and a large number of new models are being investigated in various research laboratories worldwide. Many of the current products do not contain any living cells and vary in their capacity to harness the innate capacity of the body to heal itself. Others include living cells, of allogeneic or autologous origin, and are often referred to as 'cellular therapy' or 'tissue-engineered' products. Modifications and improvements are currently investigated that aim at improving the healing potential of those products through the use of recombinant growth factors and additional features such as microvascularization. Fundamental research into wound healing and scar-free regeneration raises the hope that we will eventually be able to restore almost completely the appearance and function of skin after the healing of wounds.

[Regenerative medicine: stem cells, cellular and matricial interactions in the reconstruction of skin and cornea by tissue engineering]. / La médecine régénératrice : les cellules souches, les interactions cellulaires et matricielles dans la reconstruction cutanée et cornéenne par génie tissulaire.

Considering that there is a shortage of organ donor, the aim of tissue engineering is to develop substitutes for the replacement of wounded or diseased tissues. Autologous tissue is evidently a preferable transplant material for long-term graft persistence because of the unavoidable rejection reaction occuring against allogeneic transplant. For the production of such substitutes, it is essential to control the culture conditions for post-natal human stem cells. Furthermore, histological organization and functionality of reconstructed tissues must approach those of native organs. For self-renewing tissues such as skin and cornea, tissue engineering strategies must include the preservation of stem cells during the in vitro process as well as after grafting to ensure the long-term regeneration of the transplants. We described a tissue engineering method named the self-assembly approach allowing the production of autologous living organs from human cells without any exogenous biomaterial. This approach is based on the capacity of mesenchymal cells to create in vitro their own extracellular matrix and then reform a tissue. Thereafter, various techniques allow the reorganization of such tissues in more complex organ such as valve leaflets, blood vessels, skin or cornea. These tissues offer the hope of new alternatives for organ transplantation in the future. In this review, the importance of preserving stem cells during in vitro expansion and controlling cell differentiation as well as tissue organization to ensure quality and functionality of tissue-engineered organs will be discussed, while focusing on skin and cornea.

Risk factors for X-ray pneumonia in the first year of life and its relation to wheezing: a longitudinal study in a socioeconomic disadvantaged population.

BACKGROUND: Although thousands of infants under the age of 12 months die each year from pneumonia in Latin America, little is known regarding the true occurrence of pneumonia, wheezing and other related respiratory illnesses in this age group. METHODS AND RESULTS: In order to describe the prevalence and risk factors for radiologically confirmed pneumonia during the first year of life, a birth-cohort (n = 188) of infants born in a low-income area in Santiago, Chile was followed up monthly. RESULTS: The prevalence of pneumonia during the first year of life was 13.3 % and there were no fatal events. Exclusive breastfeeding during the first 4 months of life was more prevalent in the non pneumonia group; conversely, wheezing episodes during 0-3 and 3-6 months of age, and hospitalization due to lower respiratory infection during 3-6 and 9-12 months of age were more prevalent in the pneumonia group. After a logistic multivariate analysis, the only risk factor that remained related with pneumonia was wheezing during the first 3 months of life (adjusted OR: 7.7, 95 CI: 1.32-44.92, p = 0.024); while breastfeeding during the first 4 months was an independent protective factor for pneumonia (adjusted OR: 0.11, 95 CI: 0.03-0.44, p = 0.002). CONCLUSION: The significant protective effect of exclusive breast feeding against pneumonia in this cohort and the evident role of recurrent wheezing as risk factor for pneumonia during the first year of life support the implementation or reinforcement of public policies encouraging exclusive breastfeeding and an adequate management of wheezing since the first months of life.