Early Macrophage Infiltration and Sustained Inflammation in Kidneys From Deceased Donors Are Associated With Long-Term Renal Function.

Kidney transplants from living donors (LDs) have a better outcome than those from deceased donors (DDs). Different factors have been suggested to justify the different outcome. In this study, we analyzed the infiltration and phenotype of monocytes/macrophages and the expression of inflammatory and fibrotic markers in renal biopsy specimens from 94 kidney recipients (60 DDs and 34 LDs) at baseline and 4 months after transplantation. We evaluated their association with medium- and long-term renal function. At baseline, inflammatory gene expression was higher in DDs than in LDs. These results were confirmed by the high number of CD68-positive cells in DD kidneys, which correlated negatively with long-term renal function. Expression of the fibrotic markers vimentin, fibronectin, and α-smooth muscle actin was more elevated in biopsy specimens from DDs at 4 months than in those from LDs. Gene expression of inflammatory and fibrotic markers at 4 months and difference between 4 months and baseline correlated negatively with medium- and long-term renal function in DDs. Multivariate analysis point to transforming growth factor-ß1 as the best predictor of long-term renal function in DDs. We conclude that early macrophage infiltration, sustained inflammation, and transforming growth factor-ß1 expression, at least for the first 4 months, contribute significantly to the difference in DD and LD transplant outcome.

Monocyte implication in renal allograft dysfunction.

Macrophages are involved in the development and progression of kidney fibrosis. The aim of this study was to analyse the phenotype of circulating monocytes and their ability to predict kidney allograft dysfunction in living kidney transplant recipients. Whole blood samples from 25 kidney recipients and 17 donors were collected at five time-points. Monocyte phenotype was analysed by flow cytometry, and interleukin (IL)-10 and soluble CD163 by enzyme-linked immunosorbent assay. One week after transplantation, surface CD163 and IL-10 levels increased significantly from baseline [2·99 ± 1·38 mean fluorescence intensity (MFI) to 5·18 ± 2·42 MFI for CD163; 4·5 ± 1·46 pg/ml to 6·7 ± 2·5 pg/ml for IL-10]. This CD163 increase correlated with 4-month creatinine levels (r = 0·4394, P = 0·04). However, soluble CD163 decreased significantly from baseline at 1 week (797·11 ± 340·45 ng/ml to 576·50 ± 293·60 ng/ml). CD14(+) CD16(-) monocytes increased at 4 months and correlated positively with creatinine levels at 12 and 24 months (r = 0·6348, P = 0·002 and r = 0·467, P = 0·028, respectively) and negatively with Modification of Diet in Renal Disease (MDRD) at 12 months (r = 0·6056, P = 0·003). At 4 months, IL-10 decreased significantly (P = 0·008) and correlated positively with creatinine at 2 years (r = 0·68, P = 0·010) and with CD14(+) CD16(-) monocytes at 4 months (r = 0·732, P = 0·004). At 24 h, levels of human leucocyte antigen D-related declined from 12·12 ± 5·99 to 5·21 ± 3·84 and CD86 expression decreased from 2·76 ± 1·08 to 1·87 ± 0·95. Both markers recovered progressively until 12 months, when they decreased again. These results indicate that monitoring monocytes could be a promising new prognostic tool of graft dysfunction in renal transplant patients.

Mycophenolate as maintenance therapy for lupus nephritis with impaired renal function.

BACKGROUND: Mycophenolate (MF) is effective as a maintenance therapy after induction therapy in patients with lupus nephritis (LN). However, little is known about its role in patients with impaired renal function. The purpose of this study was to evaluate the efficacy and safety of MF as a maintenance therapy for LN and its association with renal function. METHODS: Data were obtained for 56 Spanish patients who were receiving MF as a maintenance therapy for LN. Patients were classified into two groups according to renal function at the initiation of MF treatment: group 1 [estimated glomerular filtration rate (eGFR) ≥60 ml/min/1.73 m(2)] and group 2 (eGFR <60 ml/min/1.73 m(2)). The primary endpoints of the study were the rates of renal relapse and responses, and their relationship with baseline renal function. Secondary outcomes were the appearance of side effects during treatment. RESULTS: At initiation of MF treatment, the only differences between the groups were for age, hemoglobin levels, anti-DNA antibody titer, proteinuria, and renal function. In group 1 (n = 38), the eGFR was 98 ± 34 ml/min/1.73 m(2) and in group 2 (n = 18) the eGFR was 43 ± 14 ml/min/1.73 m(2). Only 3 cases had an eGFR <30 ml/min/1.73 m(2). No significant differences were observed in the rate of relapse at 6 months (group 1: 20%; group 2: 23%) or at 12 months (group 1: 25%; group 2: 17%). Response rates were also similar in both groups. Side effects were unremarkable. CONCLUSIONS: MF is effective and safe as a maintenance therapy for LN both in patients with normal renal function and in those with renal impairment.

Molecular biology of water and salt regulation in the kidney.

The kidney plays a central role in the regulation of the salt and water balance, which depends upon an array of solute and water transporters in the renal tubules and upon vascular elements in the various regions of the kidney. Many recent studies have improved our understanding of this process. In this review, we summarize the current data on the molecules involved in sodium and water transport in the renal tubules, focusing in particular on aquaporins and renal sodium transporters and channels.

Anaesthetic management of thyroid storm in a patient with Friederich's ataxia. A case report.

A 26-year-old patient with Friederich's ataxia with hypertrophic obstructive cardiomyopathy undergoing total thyroidectomy due to persistent amiodarone-induced thyrotoxicosis (despite high doses of antithyroid drugs and corticosteroids), presented an intraoperative episode suggestive of thyroid storm. Thyroid storm is an endocrine emergency that is associated with high morbidity and mortality. Early diagnosis and treatment, which is of vital importance to improve survival, includes symptomatic treatment, treatment of cardiovascular, neurological, and/or hepatic manifestations and thyrotoxicosis, measures to suppress or avoid triggering stimuli, and definitive treatment.

Mycophenolate as induction therapy in lupus nephritis with renal function impairment.

BACKGROUND: Mycophenolate (MF) is effective as induction therapy for lupus nephritis (LN) in patients with normal renal function; however, little is known about its role in patients with impaired renal failure. The purpose of this study was to evaluate the response to MF in LN and its association with baseline renal function. METHODS: Data were obtained for 90 patients from 12 Spanish renal units who were receiving MF as induction therapy for LN. Patients were classified into 2 groups: group 1 (estimated glomerular filtration rate [eGFR] ≥60 ml/min/1.73 m(2)) and group 2 (eGFR <60 ml/min/ 1.73 m(2)). The primary outcome measure was the percentage of patients who achieved any response and its relationship with initial eGFR. The secondary outcome measures were the percentage of patients who achieved a complete response (CR) or partial response (PR) and the appearance of relapses during treatment and side effects. RESULTS: At initiation of MF treatment, there were no differences in the main parameters between group 1 (n = 63; eGFR 87 ± 23 ml/min/ 1.73 m(2)) and group 2 (n = 27; eGFR 44 ± 12 ml/min/1.73 m(2)). Exposure to prednisone and MF was similar. The percentages of patients who achieved a response in groups 1 and 2 were, respectively, 69.2 and 43.8% at 6 months and 81.3 and 73.7% at 12 months. CR was more frequent in group 1, whereas PR was similar in both groups. Four patients relapsed and side effects were unremarkable. CONCLUSIONS: MF is effective and safe as induction therapy for LN, and response is even achieved in patients with baseline renal impairment.

Use of a single dose of 70mg/kg chloral hydrate as a hypnotic in nuclear magnetic resonance. A prospective study of 3132 cases.

OBJECTIVE: To assess the mean time to hypnosis, hemodynamic stability, and incidence of complications associated with the administration of 70mg/kg oral chloral hydrate in children scheduled for magnetic resonance imaging (MRI). MATERIAL AND METHODS: Prospective study conducted from January 2000 to January 2020 in which 3132 patients aged between one day and 5 years underwent MRI under anaesthesia in an outpatient setting. The study population was divided into 4 subgroups: A) aged between one and 30 days; B) aged between one month and one year; C) aged between one and 3 years, and D) aged between 3 and 5 years. Study variables were: sex, age, type of examination, mean imaging time, mean time to awakening, heart rate before and after MRI, SatO2, and incidence of complications such as respiratory depression (SatO2 below 90%), agitation during the MRI or on awakening (intense crying lasting more than 2min), prolonged sedation measured on the Steward scale, and nausea and/or vomiting during the MRI, on awakening, or at home. RESULTS: No notable hemodynamic alterations were observed. The incidence of desaturation was .41%, awakening during the test was .16%, prolonged sedation was 1.08%, and agitated awakening was 1.46%. Nausea and vomiting at the end of the test had an incidence of .73%. The P value in all cases was <.05%. CONCLUSIONS: Chloral hydrate at a dose of 70mg/kg continues to be suitable in sedation lasting no more than one hour for non-invasive procedures in children, and is associated with adequate haemodynamic stability with practically no side effects.

Silver jubilee: 25 years of the first demonstration of the direct effect of phosphate on the parathyroid cell.

Although phosphorus is an essential element for life, it is not found in nature in its native state but rather combined in the form of inorganic phosphates (PO43-), with tightly regulated plasma levels that are associated with deleterious effects and mortality when these are out of bounds. The growing interest in the accumulation of PO43- in human pathophysiology originated in its attributed role in the pathogenesis of secondary hyperparathyroidism (SHPT) in chronic kidney disease. In this article, we review the mechanisms by which this effect was justified and we commemorate the important contribution of a Spanish group led by Dr. M. Rodríguez, just 25 years ago, when they first demonstrated the direct effect of PO43- on the regulation of the synthesis and secretion of parathyroid hormone by maintaining the structural integrity of the parathyroid glands in their original experimental model. In addition to demonstrating the importance of arachidonic acid (AA) and the phospholipase A2-AA pathway as a mediator of parathyroid gland response, these findings were predecessors of the recent description of the important role of PO43- on the activity of the calcium sensor-receptor, and also fueled various lines of research on the importance of PO43- overload not only for the pathophysiology of SHPT but also in its systemic pathogenic role.

WT1 mutations may be a cause of severe renal failure due to nephroblastomatosis in Wilms' tumor patients.

Wilms' tumor suppressor gene (WT1) encodes a transcription factor required for normal development of the genitourinary system. Germline WT1 mutations have been described in a wide spectrum of pathological conditions, including kidney diseases, genital abnormalities and Wilms' tumor. Here we report a 4-year-old male patient who presented with bilateral cryptorchidism, Wilms' tumor, nephroblastomatosis and renal failure without nephrotic proteinuria. Sequence analysis of the WT1 gene demonstrated a constitutional heterozygous nonsense mutation in exon 7, which leads to a truncation of the WT1 protein at the zinc-finger 1. In the DNA of the tumor, we observed the same mutation in homo/hemizygosity. Given the requirement of WT1 for normal development, the WT1 mutation is likely to be responsible for the nephroblastomatosis and, in consequence, for the severe renal failure observed in our patient. This finding extends the spectrum of kidney diseases related to WT1 mutations and points to the need to screen for this gene in children with genitourinary abnormalities and Wilms' tumor because of the associated risk of nephroblastomatosis and renal failure in those carrying WT1 mutations.

[Reflections on residency training under the current recommendations of the European Union of Medical specialists and the European Board of Anaesthesia (UEMS/EBA guidelines)]. / Consideraciones formativas ante el actual escenario europeo programa formativo postgraduado. UEMS/EBA guidelines.

The recent publication of guidelines for postgraduate training in anesthesiology, pain, and intensive care issued by the European Board of Anaesthesia (EBA) and the European Union of Medical Specialists (UEMS) (http://www.sedar.es/revistasedar/uems.pdf) specifies directions we must take with our residents. The training section of the Sociedad Española de Anestesiología y Reanimación (SEDAR) has decided to make the guidelines available on the association's website so that the UEMS/EBA proposals can be compared to the training program drafted by the Spanish national board for our specialty. Our aim is to identify points of convergence between the two proposals and to target gaps where improvements can be made so that Spanish residency training in this specialty is in harmony with the European framework.

Use of a single dose of 70mg/kg chloral hydrate as a hypnotic in nuclear magnetic resonance. A prospective study of 3,132 cases. / Uso de hidrato de cloral a dosis única de 70mg/kg como hipnótico en resonancia magnética nuclear. Estudio prospectivo de 3.132 casos.

OBJECTIVE: To assess the mean time to hypnosis, hemodynamic stability, and incidence of complications associated with the administration of 70mg/kg oral chloral hydrate in children scheduled for magnetic resonance imaging (MRI). MATERIAL AND METHODS: Prospective study conducted from January 2000 to January 2020 in which 3,132 patients aged between one day and 5 years underwent MRI under anaesthesia in an outpatient setting. The study population was divided into 4 subgroups: A) aged between one and 30 days; B) aged between one month and one year; C) aged between one and 3 years, and D) aged between 3 and 5 years. Study variables were: sex, age, type of examination, mean imaging time, mean time to awakening, heart rate before and after MRI, SatO2, and incidence of complications such as respiratory depression (SatO2 below 90%), agitation during the MRI or on awakening (intense crying lasting more than 2min), prolonged sedation measured on the Steward scale, and nausea and/or vomiting during the MRI, on awakening, or at home. RESULTS: No notable hemodynamic alterations were observed. The incidence of desaturation was 0.41%, awakening during the test was 0.16%, prolonged sedation was 1.08%, and agitated awakening was 1.46%. Nausea and vomiting at the end of the test had an incidence of 0.73%. The P value in all cases was<.05%. CONCLUSIONS: Chloral hydrate at a dose of 70mg/kg continues to be suitable in sedation lasting no more than one hour for non-invasive procedures in children, and is associated with adequate haemodynamic stability with practically no side effects.

[Relationship between renal size and blood pressure profile in patients with autosomal dominant polycystic kidney disease without renal failure]. / Relación entre el tamaño renal y el perfil de presión arterial en pacientes con poliquistosis renal autosómica dominante sin insuficiencia renal.

BACKGROUND: Enlargement of renal size plays an important role in the development of hypertension in patients with autosomic dominant polycystic kidney disease (ADPKD) and normal renal function. METHODS: A 24h blood pressure monitoring (ABPM) and a renal echography have been performed in 37 patients with ADPKD and estimated glomerular filtration rate > 60 ml/min/1.73 m(2) to study the relationship between renal size and an altered blood pressure profile in prehypertension stages. RESULTS: 13 patients had normal blood pressure, 11 were diagnosed of masked hypertension, 4 had white coat hypertension and 9 had hypertension. We have found in the normotensive group with a dipper blood pressure profile a positive and statistically significant relationship between renal size and diastolic blood pressure variability. CONCLUSIONS: ABPM helps to make an early diagnosis of hypertension and to identify those patients with masked hypertension. This study suggests a relationship between renal size and a blood pressure profile linked to a major cardiovascular risk in normotensive patients with ADPKD.

Dietary and pharmacological control of calcium and phosphate metabolism in dialysis patients.

Chronic kidney disease-mineral and bone disorder is a new term defining a complex syndrome which underlines the need of a systemic approach to disturbances of calcium and phosphate metabolism in patients with renal failure. In recent years, the availability of new phosphorus binders and the appearance of new selective vitamin D receptor activators and calcimimetics have increased our current armamentarium and have changed previous paradigms. All these drugs can be used in combination, acting in distinct yet complementary pathways, with a resultant improvement in their individual clinical profile and reduction in secondary effects, while enhancing the achievement of clinical guideline targets. On the other hand, we should be aware that treatment costs are increasing and most of our knowledge is opinion-based. In this article, we shall consider rational recommendations on the control of calcium, phosphorus and parathyroid hormone while awaiting new evidence. We shall also briefly review some important related issues such as vascular calcification, adynamic bone disease, osteoporosis and the need of parathyroidectomy. Future guidelines may modify current recommendations, but we believe that the lack of an absolute evidence is not equivalent to the lack of awareness of the important problem which chronic kidney disease-mineral and bone disorder represents.

Preservation of renal function in a patient with Fabry nephropathy on enzyme replacement therapy.

Fabry disease is an X-linked recessive inborn error of glycosphingolipid metabolism caused by the deficient activity of the lysosomal enzyme, alpha-galactosidase A. Enzyme replacement therapy (ERT) for this disorder has been available in Europe since 2001. However, its effect on advanced renal failure remains controversial. We report the case of a patient whose decline in renal function was reduced by the administration of ERT (agalsidase-alpha). This reduction was more pronounced after doubling the dose of the enzyme. The rate of deterioration of eGFR went from 6.3 ml/min/year prior to the start of ERT (0.2 mg/kg) to 2 ml/min/year (0.4 mg/kg). To our knowledge, this is the first reported case of a patient with moderately impaired renal function treated with high doses of ERT and follow-up of 6 years. The data shown here suggest that ERT may have a very positive impact on renal function even in advanced stages. The role of proteinuria and its control seem to have a clear responsibility for this favorable outcome.

[Management of immune suppression in systemic diseases affecting the kidney]. / Manejo de la inmunosupresión en enfermedades sistémicas que afectan al riñón.

We reviewed the literature in 2007 on 3 groups of systemic diseases affecting the kidney: lupic nephropathy (LN), small vessel vasculitis (SVV) and renal amyloidosis. A systematic review of 268 patients with LN pooled from 4 studies found that mycophenolic acid (MPA) in the induction phase caused more remissions and achieved greater renal survival than cyclophosphamide (CP), confirming it as a valid alternative to CP. Using a protocol including rituximab and MPA in the induction phase (14 days), MPA alone without corticoids is effective and safe in the maintenance phase. Rituximab has also been successfully used in CP-resistant forms of LN, where it reduces clinical activity and mesangial proliferation. Plasma exchanges achieve better results than bolus corticoids in SVS with severe renal failure. Complications are severe. Anti- TNF-alpha agents provide no benefit in this indication. Prolonged administration of low-dose corticoids reduces the incidence of relapses. MPA is an alternative to CP if this drug cannot be administered. Good results are achieved with rituximab in CP-resistant forms. According to a controlled trial, treatment of AL amyloidosis with dexamethasone and melphalan has equivalent results to highdose melphalan and rescue with hematopoietic stem cell transplant. In AA amyloidosis, eprosidate slows the rate of progression of renal failure.

[Tables estimating glomerular filtration rate from plasma creatinine]. / Tablas para la estimación del filtrado glomerular a partir de la creatinina plasmática.

Chronic kidney disease (CKD) and its related complications have become an important health and social problem. Very expensive resources are required in end-stage renal disease, and both complications of CKD as well as the important associated cardiovascular risk demand for interventions long before renal substitution therapies are needed. Thus, early diagnosis of CKD is currently considered of paramount importance, and it is based essentially upon the estimation of the glomerular filtration rate by formulae such as the abbreviated equation of the MDRD study. Nevertheless, in spite of international published recommendations, an automatic calculation to estimate the glomerular filtration rate (GFR) from serum creatinine is not reported by most laboratories yet and the need for creatinine assay standardisation is far from being implemented. Thus, we have designed some tables to show the creatinine value corresponding to different GFR for ages between 20 and 90 y/o, at 5 years intervals and in both sexes with both the MDRD-4 and MDRD-IDMS equations (Modification of Diet in Renal Disease-Isotope Dilution Mass Spectrometry). Moreover, we have created a global table including an estimation of GFR from plasma creatinine, age and sex by the MDRD-IDMS formula, the recommended for those laboratories which measure serum creatinine with assays aligned to the reference method. These tables aim to increase the awareness of the different assays for serum creatinine and to facilitate the diagnosis of CKD converting serum creatinine into GFR. This action should allow not only the early detection but also the possibility to establish the appropriate medical actions recommended after CKD detection.

[Pregnancy in recipients of kidney transplantation: effects on mother and child]. / Embarazo en receptoras de trasplante renal: efectos en la madre y en el niño.

When the field of transplantation was first developing, physicians worried about the teratogenicity of immunosuppressive medications and considered pregnancy ill-advised. The purpose of this study is to analyze pregnancy after kidney transplantation and their consequences on mother, graft and child. We review ten pregnant women with kidney transplantation, average of 29 years old and 44 months post-kidney transplantation. The mean glomerular filtration rate was 64 ml/min and the immunosuppression was with prednisone and tacrolimus. We analyze outcomes of different variables before and during pregnancy, and after labour. Pregnancy finished in nine of ten patients. Three patients needed cesarean section and only one patient had a miscarriage on the first term. Blood arterial pressure increased at the end of pregnancy and the creatinine level was stable with a few increase of proteinuria at the third term. We increased the tacrolimus dose to obtain the correct blood levels and any rejection was detected. We had only one patient with preeclampsia that we solved with a cesarean section. Labours were a mean of 37.2 weeks and the mean birth weight of infant was 2,809 grams. Two newborns had prematurity without structural malformations. Pregnancy after kidney transplantation is safe with prednisone and tacrolimus when the renal function is good, proteinuria doesn't exist and blood pressure is controlled.

[Prophylactic and pre-emptive therapy for cytomegalovirus infection in kidney transplant patients using oral valganciclovir]. / Tratamiento profiláctico y anticipado de la infección por citomegalovirus en pacientes trasplantados renales mediante valganciclovir oral.

UNLABELLED: Prophylactic and pre-emptive therapy with oral valganciclovir for cytomegalovirus infection in renal transplant recipients. BACKGROUND: Cytomegalovirus infection is a very important health problem in solid organ transplant recipients (SOT). Once-daily valganciclovir has been shown to be as clinically effective and well tolerated as oral ganciclovir tid in the prevention of CMV infection in high risk SOT recipients. METHODS: The aim of the present study was to evaluate the incidence and severity of CMV disease in 150 renal transplant recipients that received either prophylactic [high risk group (HR), N = 66] or pre-emptive [low risk group (LR), N = 84] therapy with oral valganciclovir (900 mg/day vo) for three months according to their basal risk. Patients were monitored for signs and symptoms of CMV disease and CMV plasma viral load was assessed weekly. RESULTS: A total of 31 patients (47%) of the HR and 26 patients (31%) of the LR presented a positive CMV PCR result. Twelve patients (14.3%) in the LR that had a high viral load (CMV PCR > 1,000 copies/mL) but remained asymptomatic received pre-emptive therapy. Four patients (4.7%) in the LR, after an average time of 35 days after transplant and two patients (4.5%) in the HR, after prophylactic treatment was completed, developed CMV disease. The disease was mild-moderate in most of the cases. Those patients that developed CMV disease responded to treatment with iv ganciclovir for 14 days followed by treatment with oral valganciclovir for up to three months. CONCLUSION: Prophylactic treatment with oral valganciclovir for CMV prevention is only required in high risk solid organ transplant recipients.

Determinants of renal and patient outcomes in a Spanish cohort of patients with ANCA-associated vasculitis and renal involvement.

The classification of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) remains controversial. The main objective of this study was to define the respective values of ANCA serotype-based classification, clinicopathological classification, and histopathological classification in predicting patient and renal outcomes in a Spanish cohort of patients with ANCA with specificity for myeloperoxidase, MPO-ANCA, versus ANCA with specificity for proteinase 3, PR3-ANCA. Two hundred and forty-five patients with ANCA-AAV and biopsy-proven renal involvement diagnosed between 2000 and 2104 were recruited in 12 nephrology services. Clinical and histologic data, renal outcomes, and mortality were analyzed. We applied the Chapel Hill Consensus Conference definition with categories for granulomatosis with the polyangiitis (GPA) and microscopic polyangiitis (MPA), the classification based on ANCA specificity, and the histopathological classification proposed in 2010. Eighty-two percent were MPO-ANCA positive and 18.0% PR3-ANCA positive. Altogether, 82.9% had MPA and 17.1% GPA. The median follow-up was 43.2 months (0.1-169.3). Neither ANCA-based serological nor clinical classification was predictive of renal outcomes or patient survival on bivariate or multivariate Cox regression analysis. Histopathological classification was found to predict development of end-stage renal disease (p = 0.005) in Kaplan-Meier analysis. ANCA specificity was more predictive of relapse than clinicopathological classification in multivariate analysis (HR 2.086; 95% CI 1.046-4.158; p = 0.037). In our Spanish cohort, a majority of patients had an MPO-ANCA-AAV. A classification based on ANCA specificity has a higher predictive value for relapse occurrence and could be used for decision-making with respect to induction treatment and maintenance therapies.

[Locating the site of resistance to the endotracheal tube in fiberoptic oral intubation and maneuvers to overcome it: a mannequin simulation study]. / Intubación fibroóptica oral. Localización del lugar de resistencia al avance del tubo traqueal y maniobras para solucionarlo. Estudio de simulación en maniquí.

OBJECTIVE: To determine the most common tracheal points of resistance during orotracheal insertion of a fiberoptic tube in a mannequin by applying a maneuver algorithm to overcome the resistance. METHOD: Four study groups were established to compare 2 types of endotracheal tube: a standard tube and a reinforced flexible tube with an internal diameter of 7.5 mm. The tubes were used on their own or in combination with a Williams airway intubator. Two fiberoptic bronchoscopes were used, one to perform the test intubation and the other to observe the location of resistance and the effectiveness of the maneuvers for overcoming it. The degree of resistance was scored using a modified Jones scale, from 0 (intubation without resistance) to 4 (intubation impossible); location of resistance and time required for each intubation were also recorded. RESULTS: A total of 250 oral intubations were performed. Resistance was encountered in 75.2% of the cases. The main locations of obstruction were the right arytenoid cartilage and the posterior commissure. In 89.6% of the cases, intubation of the trachea was achieved without maneuvering or with a 90 degrees counterclockwise rotation. Statistically significant differences were found in resistance and intubation time when the reinforced flexible tube was used with the Williams intubator. CONCLUSIONS: Rotating the tube 90 degrees counterclockwise was an effective maneuver for overcoming resistance. The combination of a reinforced flexible tube and a Williams intubator was associated with less resistance and shorter intubation times.