Drug utilization among young adults with atopic dermatitis: Influence of sex, socio-economic status and disease severity.

BACKGROUND: Atopic dermatitis (AD) affects individuals of all ages, and the first-line treatment are emollients and topical corticosteroids. There is insufficient knowledge about factors possibly affecting the drug utilization of young adults with AD. OBJECTIVES: To describe the drug utilization of young adults with AD in relation to sex, socio-economic status and disease severity. METHODS: A cross-sectional study based on the 24-year follow-up from the population-based BAMSE (Children, Allergy, Milieu, Stockholm, Epidemiology Survey) birth cohort linked with dispensing data from the National Drug Register (n = 2912). Self-reported AD and socio-economic status were defined from questionnaire data and disease severity was determined through the clinical examination and Patient-Oriented Eczema Measure questionnaire. RESULTS: The prevalence of AD in young adults was 17.7% (n = 516) and 45.5% of them were dispensed at least one drug for the treatment of AD during the study period (January 2016 to June 2019). Topical corticosteroids (TCS) were the most common drugs (32.9%) followed by emollients (21.7%). A larger proportion of men were dispensed TCS than women (39.0% vs. 29.1%: p-value = 0.020). A larger proportion of young adults with moderate-to-severe AD were dispensed TCS than those with mild AD (52.6% vs. 35.3%: p-value = 0.026). No one was dispensed the recommended amount of emollients and less than five individuals were dispensed the recommended amount of TCS for mild disease. Male sex (adj.OR 1.54, 95% CI 1.06-2.34) and moderate-to-severe AD (adj.OR 2.62, 95% CI 1.59-4.31) were associated with dispensation of TCS. CONCLUSIONS: A large proportion of young adults with AD was undertreated or untreated. Sex and disease severity did affect the dispensing patterns of investigated drugs.

Exploring pharmacists' perspectives about substandard and falsified medical products through interviews.

Background: The problem with substandard and falsified (SF) medical products may grow in high-income countries when e-commerce of medicines increases. Unauthorized websites offer medicines of insufficient quality. This underscores the importance of evaluating how the problem with SF medical products can be prevented from escalating. However, little is known about what knowledge and experience professionals working primarily with medicines have about the phenomenon. Objective: This study was conducted to explore purposively selected pharmacists' experience and knowledge about SF medical products. Methods: Twelve individual interviews were conducted with purposively selected pharmacists between May 2021 and September 2021. An interview guide was used with specific questions about e-commerce, which focused on exploring pharmacists' experience and knowledge about SF medical products. The interviews lasted, on average, 49 min and were analyzed using inductive qualitative content analysis. Results: A main theme 'Pharmacists as guardians of safe medicines' emerged. This theme consisted of three categories pinpointing 'risk factors', 'protective factors', and 'opportunities for improvement' regarding SF medical products. Findings suggest that pharmacists can play a role in preventing the problem with SF medical products from escalating. Participants emphasized they were in this line of work to help patients and increase patient safety. Conclusions: Pharmacists have the opportunity to empower the public with knowledge about SF medical products since they discuss medicines with many people every day. Awareness of risk factors for SF medical products enables pharmacists to guide patients to avoid risky purchases from unauthorized websites. To do this, better communication, and cooperation with patients and other healthcare professionals are needed.

Childhood atopic dermatitis is associated with cardiovascular risk factors in young adulthood-A population-based cohort study.

BACKGROUND: Studies have indicated that atopic dermatitis (AD) is associated with an increased risk of cardiovascular disease (CVD). However, data are conflicting. Furthermore, the longitudinal effect of childhood AD on cardiovascular risk factors in young adulthood is less investigated. OBJECTIVES: To assess associations between AD in childhood and CVD risk factors in young adulthood. METHODS: The study encompasses longitudinal data from a population-based birth cohort. Participants with data up to age 24 years were included (n = 2270). The primary outcomes were body mass index (BMI), waist circumference (WC), body fat per cent (BF%) and blood pressure (BP) at 24 years. The secondary outcome was blood lipids. Severe AD was defined as AD in combination with sleep disturbance due to itching. RESULTS: In total, 18.6% (n = 420) had AD at 24 years. Males with AD had higher BMI (ßAdj. 0.81, 95% CI 0.15-1.47), BF% (ßAdj. 1.19, 95% CI 0.09-2.29), systolic BP (ßAdj. 1.92, 95% CI 0.02-3.82), total cholesterol (ßAdj. 0.14, 95% CI 0.00-0.28) and LDL cholesterol (ßAdj. 0.15, 95% CI 0.02-0.27) compared with males without AD. No associations were seen in females. Current AD with prepubertal onset was associated with increased BMI in both males (ßAdj. 0.89, 95% CI 0.11-1.67) and females (ßAdj. 0.72, 95% CI 0.11-1.33). At 24 years, 23.1% (n = 97) of all with AD, had severe disease, which was significantly associated with overweight in both sexes, with BMI (ßAdj. 1.83, 95% CI 0.72-2.94), WC (ßAdj. 4.03, 95% CI 1.54-6.52) and BF% (ßAdj. 2.49, 95% CI 0.60-4.39) in females and with BF% (ßAdj. 2.96, 95% CI 0.23-5.69) in males, compared with peers with mild to moderate AD. CONCLUSION: AD in males appears to be associated with CVD risk factors in young adulthood. The duration and severity of AD seem to be of importance in both sexes.

Swedish community pharmacy employees' knowledge and experience of substandard and falsified medical products: a cross-sectional descriptive survey.

OBJECTIVES: Substandard and falsified medical products are, according to the World Health Organization, a global threat to public health. To evaluate if community pharmacy employees can guide the public to safer medication purchases, their knowledge and experience about SF medical products was examined. METHODS: A digital questionnaire was distributed to the five dominating pharmacy companies in Sweden, representing 97% of the community pharmacies (1391/1433), giving the theoretical possibility of reaching 6200 employees. Three companies published a link to the questionnaire on their intranets, one distributed the link via e-mail to the responsible pharmacist for quality and knowledge, respectively. The fifth company did not pass on, due to technical problems. Employees aged 18 years or older with customer contact were invited to participate. KEY FINDINGS: The questionnaire was available for 74% of all community pharmacies (1067/1433), having approximately 4900 employees with customer contact. The response rate was 5% (228/4900). Of the respondents, 89% were pharmacists (203/228), 84% were women (191/228) and 43% were 35-49 years (98/228). The respondents worked in pharmacies of different size, located both in rural and urban areas. The definition of substandard and falsified medical products was known by 182 of the 228 respondents (80%) and the main source of knowledge was media (61%, 111/228). The common European logo for authorized online pharmacies was not recognized by 74% (169/228). CONCLUSIONS: For pharmacy employees to guide the public to safer medication purchases, knowledge about substandard and falsified medical products needs to be enhanced specially about legal international e-commerce.

Prevalence and characteristics of atopic dermatitis among young adult females and males-report from the Swedish population-based study BAMSE.

BACKGROUND: There is limited knowledge regarding prevalence and characteristics of atopic dermatitis (AD) among young adults in the general population. OBJECTIVES: To study AD among young adults in a Swedish population-based birth cohort, with a particular focus on prevalence, sex differences including risk for AD at different ages, disease course and characteristics of AD at 24 years. METHODS: The BAMSE cohort includes 4089 individuals who have been followed regularly from birth to age 24 years regarding AD and atopic diseases. For this study 3055 individuals who answered questions regarding AD at the 24-year follow-up were included. All were invited to a clinical examination including skin examination, evaluation by William's criteria and collection of blood for analysis of specific IgE, and 2264 individuals chose to participate. RESULTS: At 24 years, the 12-month prevalence of AD was 17.8% and more females than males had AD (20.5% vs. 14.8%), P < 0.0001. The point prevalence of ongoing AD at clinical examination was 8.0%. AD severity as assessed by Patient-Oriented Eczema Measure (POEM) did not differ between sexes. The proportion of adult onset of AD was 16.9% (92 of 543), females 17.3% vs. males 16.4%. More females than males with AD at 24 years reported disturbed sleep due to itch (26.1% vs. 15.5%, P < 0.003). IgE sensitization was less common among females with AD than males with AD (61.3% vs. 79.6%, P < 0.0001). In addition, male sex (female sex being the reference) was associated with increased odds for AD the first year of life (OR: 1.31, 95% CI; 1.10-1.56), and decreased odds of AD in adolescence and young adulthood (OR: 0.66, 95% CI; 0.55-0.80). CONCLUSIONS: Atopic dermatitis is a common disease among young adults, and even though more females than males have AD at 24 years, adult onset of AD seems to be equally prevalent among both sexes in young adulthood.

'Where and how do you buy medicines?' A pilot survey of consumption strategies among the public in Sweden.

BACKGROUND: Substandard and falsified (SF) medical products are a major danger to public health. They affect every region of the world, and have been identified in all major therapeutic categories. Studies from medicine, pharmacology, law and public health dominate this research area with a focus on the supply side. However, the spread of SF medical products cannot be fully understood without information about the demand side or a sociocultural perspective on market formation. The aim of this short report is to present findings from a pilot study that examines the attitudes of the Swedish public regarding consumption of medicines. METHODS: We conducted a pilot survey in 2016 'Where and how do you buy medicines?' using LimeSurvey, an open-source online survey software. In total 155 respondents completed the survey. RESULTS: The majority of respondents turn to doctors within healthcare for prescription-only medicines (POM). Simultaneously, some respondents would consider buying POMs without prior contact with experts even if medicines may come from unsafe sources. CONCLUSIONS: There is a tendency that people move away from formal healthcare towards an unregulated market. In parallel, people's approach to doctors becomes more personalized and pragmatic than in former patriarchal relationships. Risk becomes a negotiable concept.

Substandard and falsified medical products are a global public health threat. A pilot survey of awareness among physicians in Sweden.

BACKGROUND: Substandard and falsified medical products are a public health threat, primarily associated with low- and middle-income countries. Today, the phenomenon also exists in high-income countries. Increased Internet access has opened a global market. Self-diagnosis and self-prescription have boosted the market for unregulated websites with access to falsified medicines. AIM: To describe the state of knowledge and experience on SF medical products among emergency physicians (EPs) and general practitioners (GPs) in Sweden. METHODS: An online survey with anonymous answers from 100 EPs and 100 GPs. Physicians were recruited from TNS SIFO's medical database. The term in the survey was 'illegal and falsified medicines' which was common in Sweden at that time. It corresponds well with the term 'substandard and falsified medical products' that the WHO launched shortly after our data collection. We report our results with this term. RESULTS: In Sweden, 78.5% of the physicians had heard the term 'illegal and falsified medicines' and 36.5% had met patients they suspected had taken it. Physicians lacked awareness of the use of the reporting system and wanted more knowledge about how to deal with patients who have possibly used falsified medicines. CONCLUSIONS: To meet the public health threat of SF medical products, physicians need more knowledge.

Vasopressin and nitroglycerin decrease portal and hepatic venous pressure and hepato-splanchnic blood flow.

BACKGROUND: Various methods are used to reduce venous blood pressure in the hepato-splanchnic circulation, and hence minimise blood loss during liver surgery. Previous studies show that combination of vasopressin and nitroglycerin reduces portal pressure and flow in patients with portal hypertension, and in this study we investigated this combination in patients with normal portal pressure. METHOD: In all, 13 patients were studied. Measurements were made twice to confirm baseline (C1 and BL), during vasopressin infusion 4.8 U/h (V), and during vasopressin infusion combined with nitroglycerin infusion (V + N). Portal venous pressure (PVP), hepatic venous pressure (HVP), central haemodynamics and arterial and venous blood gases were obtained at each measuring point, and portal (splanchnic) and hepato-splanchnic blood flow changes were calculated. RESULTS: Vasopressin alone did not affect PVP, whereas HVP increased slightly. In combination with nitroglycerin, PVP decreased from 10.1 ± 1.6 to 8.9 ± 1.3 mmHg (P < 0.0001), and HVP decreased from 7.9 ± 1.9 to 6.2 ± 1.3 mmHg (P = 0.001). Vasopressin reduced portal blood flow by 47 ± 19% and hepatic venous flow by 11 ± 18%, respectively. Addition of nitroglycerin further reduced portal- and hepatic flow by 55 ± 13% and 30 ± 13%, respectively. Vasopressin alone had minor effects on central haemodynamics, whereas addition of nitroglycerin reduced cardiac index (3.2 ± 0.7 to 2.7 ± 0.5; P < 0.0001). The arterial-portal vein lactate gradient was unaffected. CONCLUSION: The combination of vasopressin and nitroglycerin decreases portal pressure and hepato-splanchnic blood flow, and could be a potential treatment to reduce bleeding in liver resection surgery.

Evaluation of lung and chest wall mechanics during anaesthesia using the PEEP-step method.

BACKGROUND: Postoperative pulmonary complications are common. Between patients there are differences in lung and chest wall mechanics. Individualised mechanical ventilation based on measurement of transpulmonary pressures would be a step forward. A previously described method evaluates lung and chest wall mechanics from a change of ΔPEEP and calculation of change in end-expiratory lung volume (ΔEELV). The aim of the present study was to validate this PEEP-step method (PSM) during general anaesthesia by comparing it with the conventional method using oesophageal pressure (PES) measurements. METHODS: In 24 lung healthy subjects (BMI 18.5-32), three different sizes of PEEP steps were performed during general anaesthesia and ΔEELVs were calculated. Transpulmonary driving pressure (ΔPL) for a tidal volume equal to each ΔEELV was measured using PES measurements and compared to ΔPEEP with limits of agreement and intraclass correlation coefficients (ICC). ΔPL calculated with both methods was compared with a Bland-Altman plot. RESULTS: Mean differences between ΔPEEP and ΔPL were <0.15 cm H2O, 95% limits of agreements -2.1 to 2.0 cm H2O, ICC 0.6-0.83. Mean differences between ΔPL calculated by both methods were <0.2 cm H2O. Ratio of lung elastance and respiratory system elastance was 0.5-0.95. CONCLUSIONS: The large variation in mechanical properties among the lung healthy patients stresses the need for individualised ventilator settings based on measurements of lung and chest wall mechanics. The agreement between ΔPLs measured by the two methods during general anaesthesia suggests the use of the non-invasive PSM in this patient population. CLINICAL TRIAL REGISTRATION: NCT 02830516.

Use of emollients and topical glucocorticoids among adolescents with eczema: data from the population-based birth cohort BAMSE.

BACKGROUND: Knowledge regarding how adolescents treat their eczema is sparse. OBJECTIVES: To explore the use of emollients and topical glucocorticoids in adolescents with eczema in relation to sex and disease severity, and to study dispensing patterns of topical glucocorticoids. METHODS: Questionnaire-based data on symptoms of eczema, eczema severity and treatment with emollients and topical glucocorticoids were obtained from 3108 adolescents in the Swedish population-based birth cohort BAMSE. Severity of reported eczema was evaluated with the BAMSE Eczema Severity Score (BESS) in a questionnaire and with the Patient-Oriented Eczema Measure in clinically examined patients with current eczema (n = 247). Information on dispensed topical glucocorticoids was obtained from the Swedish Prescribed Drug Register. RESULTS: In all, 10% of the adolescents reported eczema in the preceding year: 73% mild, 17% moderate and 10% severe according to BESS. Almost all used emollients, whereas use of topical glucocorticoids was reported by 55%, with no significant difference between sexes. The likelihood of treatment with emollients and topical glucocorticoids increased when the adolescents had symptoms of current eczema [adjusted odds ratio (OR) 5·95, 95% confidence interval (CI) 1·90-18·8], but not if they had more severe eczema compared with mild eczema (adjusted OR 1·57, 95% CI 0·58-4·25). Among those with reported eczema, 24% had a topical glucocorticoid dispensed in the preceding year, and among those with moderate-to-severe current eczema 24% had a dispensed potent topical glucocorticoid. CONCLUSIONS: This population-based study indicates that adolescents with eczema are undertreated or completely untreated, even those with severe eczema.

Target temperature 34 vs. 36°C after out-of-hospital cardiac arrest - a retrospective observational study.

BACKGROUND: Intensive care for comatose survivors of cardiac arrest includes targeted temperature management (TTM) to attenuate cerebral reperfusion injury. A recent multi-center clinical trial did not show any difference in mortality or neurological outcome between TTM targeting 33°C or 36°C after out-of-hospital-cardiac-arrest (OHCA). In our institution, the TTM target was changed accordingly from 34 to 36°C. The aim of this retrospective study was to analyze if this change had affected patient outcome. METHODS: Intensive care registry and medical record data from 79 adult patients treated for OHCA with TTM during 2010 (n = 38; 34°C) and 2014 (n = 41; 36°C) were analyzed for mortality and neurological outcome were assessed as cerebral performance category. Student's t-test was used for continuous data and Fischer's exact test for categorical data, and multivariable logistic regression was applied to detect influence from patient factors differing between the groups. RESULTS: Witnessed arrest was more common in 2010 (95%) vs. 2014 (76%) (P = 0.03) and coronary angiography was more common in 2014 (95%) vs. 2010 (76%) (P = 0.02). The number of patients awakening later than 72 h after the arrest did not differ. After adjusting for gender, hypertension, and witnessed arrest, neither 1-year mortality (P = 0.77), nor 1-year good neurological outcome (P = 0.85) differed between the groups. CONCLUSION: Our results, showing no difference between TTM at 34°C and TTM at 36°C as to mortality or neurological outcome after OHCA, are in line with the previous TTM-trial results, supporting the use of either target temperature in our institution.

[Validation of the Osteomyelitis Diagnosis Score on the Basis of a Retrospective Analysis of 100 Patients with Non-Union of the Tibia]. / Validierung des Osteomyelitis-Diagnose-Scores anhand einer retrospektiven Analyse von 100 Patienten mit Tibiapseudarthrose.

Background: The accurate diagnosis of "osteomyelitis" is difficult and is often delayed. However, early and radical therapy of osteomyelitis is essential. The osteomyelitis diagnosis score (ODS) was developed to predict the probability of osteomyelitis. The aim of our study was to validate the ODS and to investigate its practicability in daily routine. Material and Methods: The ODS is based on five diagnostic procedures: 1. clinical history/risk factors, 2. clinical examination/laboratory results, 3. diagnostic imaging, 4. microbiology and 5. histopathology. Each diagnostic procedure includes numerous individual findings, which are rated with 1-6 points, depending on their relevance. If the sum of the five diagnostic criteria is ≥ 17 points, the diagnosis "osteomyelitis" can be viewed as safe, between 8-17 points as probable and between 2-7 points as possible. This retrospective study included 100 patients with non-union of the tibia (2002-2010). The patients were classified into two groups: septic non-union of the tibia (experimental intervention; gold standard: positive detection of bacteria and/or positive histology) and aseptic non-union of the tibia (control intervention; no detection of bacteria and/or histology). Epidemiological data, the score's total number of points and the number of points of the score's five diagnostic procedures were analysed. Results: 71 patients exhibited aseptic non-union of the tibia, 29 patients septic non-union. Patients with septic non-union obtained a mean of 20.8 points, and 24 at least 18 points; the diagnosis "osteomyelitis" is then presumed to be certain. Patients with aseptic non-union obtained a mean of 11.3 points, and only 3/71 patients received > 17 points. Both groups obtained the majority of points in the diagnostic procedure "clinical history". The difference between the two groups is highly significant (p < 0.001). The score's sensitivity is 82.8 %, with a specificity of 95.8 %. Conclusion: The ODS was proved to be a valid score. Patients with septic non-union were identified, even if bacteria were not detected. However, the use of the ODS is demanding, as there are 104 individual findings. Many of these individual findings were negative in all patients. It would be desirable to optimise ODS, by reducing the number of queried parameters, without reduction sensitivity.

Vasopressin-induced changes in splanchnic blood flow and hepatic and portal venous pressures in liver resection.

BACKGROUND: To minimize blood loss during hepatic surgery, various methods are used to reduce pressure and flow within the hepato-splanchnic circulation. In this study, the effect of low- to moderate doses of vasopressin, a potent splanchnic vasoconstrictor, on changes in portal and hepatic venous pressures and splanchnic and hepato-splanchnic blood flows were assessed in elective liver resection surgery. METHODS: Twelve patients were studied. Cardiac output (CO), stroke volume (SV), mean arterial (MAP), central venous (CVP), portal venous (PVP) and hepatic venous pressures (HVP) were measured, intraoperatively, at baseline and during vasopressin infusion at two infusion rates (2.4 and 4.8 U/h). From arterial and venous blood gases, the portal (splanchnic) and hepato-splanchnic blood flow changes were calculated, using Fick's equation. RESULTS: CO, SV, MAP and CVP increased slightly, but significantly, while systemic vascular resistance and heart rate remained unchanged at the highest infusion rate of vasopressin. PVP was not affected by vasopressin, while HVP increased slightly. Vasopressin infusion at 2.4 and 4.8 U/h reduced portal blood flow (-26% and -37%, respectively) and to a lesser extent hepato-splanchnic blood flow (-9% and -14%, respectively). The arterial-portal vein lactate gradient was not significantly affected by vasopressin. Postoperative serum creatinine was not affected by vasopressin. CONCLUSION: Short-term low to moderate infusion rates of vasopressin induced a splanchnic vasoconstriction without metabolic signs of splanchnic hypoperfusion or subsequent renal impairment. Vasopressin caused a centralization of blood volume and increased cardiac output. Vasopressin does not lower portal or hepatic venous pressures in this clinical setting.

Transpulmonary pressure and lung elastance can be estimated by a PEEP-step manoeuvre.

BACKGROUND: Transpulmonary pressure is a key factor for protective ventilation. This requires measurements of oesophageal pressure that is rarely used clinically. A simple method may be found, if it could be shown that tidal and positive end-expiratory pressure (PEEP) inflation of the lungs with the same volume increases transpulmonary pressure equally. The aim of the present study was to compare tidal and PEEP inflation of the respiratory system. METHODS: A total of 12 patients with acute respiratory failure were subjected to PEEP trials of 0-4-8-12-16 cmH2O. Changes in end-expiratory lung volume (ΔEELV) following a PEEP step were determined from cumulative differences in inspiratory-expiratory tidal volumes. Oesophageal pressure was measured with a balloon catheter. RESULTS: Following a PEEP increase from 0 to 16 cmH2O end-expiratory oesophageal pressure did not increase (0.5 ± 4.0 cmH2O). Average increase in EELV following a PEEP step of 4 cmH2O was 230 ± 132 ml. The increase in EELV was related to the change in PEEP divided by lung elastance (El) derived from oesophageal pressure as ΔPEEP/El. There was a good correlation between transpulmonary pressure by oesophageal pressure and transpulmonary pressure based on El determined as ΔPEEP/ΔEELV, r(2) = 0.80, y = 0.96x, mean bias -0.4 ± 3.0 cmH2 O with limits of agreement from 5.4 to -6.2 cmH2O (2 standard deviations). CONCLUSION: PEEP inflation of the respiratory system is extremely slow, and allows the chest wall complex, especially the abdomen, to yield and adapt to intrusion of the diaphragm. As a consequence a change in transpulmonary pressure is equal to the change in PEEP and transpulmonary pressure can be determined without oesophageal pressure measurements.

Determination of 'recruited volume' following a PEEP step is not a measure of lung recruitability.

BACKGROUND: It has been proposed that the analysis of positive end-expiratory pressure (PEEP)-induced volume changes can quantify alveolar recruitment. The potential of a lung to be recruited is expected to be high in acute respiratory distress syndrome (ARDS), where collapsed lung tissue is very common. The volume change that is beyond the delta volume because of the patient's compliance has been termed 'recruited volume' (RecV). However, data of patients with low and high RecV showed less severe lung disease in high 'recruiters', indicating that RecV may not equal the 'potentially recruitable lung tissue' seen in computed tomography scans. We hypothesized that RecV is higher in lung-healthy (LH) patients with little collapsed lung compared with ARDS patients. METHODS: RecV and inspiratory capacity (IC) were determined in 12 LH and in 25 ARDS patients during incremental PEEP (steps of 2 cmH2 O). RecV was determined as the time-dependent increase in end-expiratory volume following the first expiration to the new PEEP level (ΔTDV). Gas distribution in LH patients was analyzed by electric impedance tomography. RESULTS: Cumulative RecV(ΔTDV) and IC were higher (P < 0.01) in LH compared with ARDS patients, 1739 ml vs. 832 ml and 4432 ml vs. 2020 ml, respectively. In both groups, RecV correlated excellently with IC (R(2) = 0.86). In LH, RecV emanated mainly from nondependent lung regions at PEEP below 15 cmH2O. Maximum plateau pressure was reached with fewer PEEP steps in ARDS compared with LH patients (11 vs. 14, P < 0.01). CONCLUSION: Our findings suggest that RecV predominately measures a slow fraction of inflation of already aerated lung tissue and not recruitment of collapsed alveoli.

Nitroglycerine and patient position effect on central, hepatic and portal venous pressures during liver surgery.

BACKGROUND: To reduce blood loss during liver surgery, a low central venous pressure (CVP) is recommended. Nitroglycerine (NG) with its rapid onset and offset can be used to reduce CVP. In this study, the effect of NG on portal and hepatic venous pressures (PVP and HVP) in different body positions was assessed. METHODS: Thirteen patients undergoing liver resection were studied. Cardiac output (CO), mean arterial pressure (MAP) and CVP were measured. PVP and HVP were measured using tip manometer catheters at baseline (BL) in horizontal position; during NG infusion, targeting a MAP of 60 mmHg, with NG infusion and the patient placed in 10 head-down position. RESULTS: NG infusion reduced HVP from 9.7 ± 2.4 to 7.2 ± 2.4, PVP from 12.3 ± 2.2 to 9.7 ± 3.0 and CVP from 9.8 ± 1.9 to 7.2 ± 2.1 mmHg at BL. Head-down tilt during ongoing NG resulted in increases in HVP to 8.2 ± 2.1, PVP to 10.7 ± 3 and CVP to 11 ± 1.9 mmHg. CO at BL was 6.3 ± 1.1, which was reduced by NG to 5.8 ± 1.2. Head-down tilt together with NG infusion restored CO to 6.3 ± 1.0 l/min. CONCLUSION: NG infusion leads to parallel reductions in CVP, HVP and PVP at horizontal body position. Thus, CVP can be used to guide NG dosage and fluid administration at horizontal position. NG infusion can be used to reduce HVP. Head-down tilt can be used during NG infusion to improve both blood pressure and CO without substantial increase in liver venous pressure. In head-down tilt, CVP dissociates from HVP and PVP.

Lung elastance and transpulmonary pressure can be determined without using oesophageal pressure measurements.

INTRODUCTION: The aim of the present study was to demonstrate that lung elastance and transpulmonary pressure can be determined without using oesophageal pressure measurements. METHODS: Studies were performed on 13 anesthetized and sacrificed ex vivo pigs. Tracheal and oesophageal pressures were measured and changes in end-expiratory lung volume (ΔEELV) determined by spirometry as the cumulative inspiratory-expiratory tidal volume difference. Studies were performed with different end-expiratory pressure steps [change in end-expiratory airway pressure (ΔPEEP)], body positions and with abdominal load. RESULTS: A PEEP increase results in a multi-breath build-up of end-expiratory lung volume. End-expiratory oesophageal pressure did not increase further after the first expiration, constituting half of the change in ΔEELV following a PEEP increase, even though end-expiratory volume continued to increase. This resulted in a successive left shift of the chest wall pressure-volume curve. Even at a PEEP of 12 cmH(2) O did the end-expiratory oesophageal (pleural) pressure remain negative. CONCLUSIONS: A PEEP increase resulted in a less than expected increase in end-expiratory oesophageal pressure, indicating that the chest wall and abdomen gradually can accommodate changes in lung volume. The rib cage end-expiratory spring-out force stretches the diaphragm and prevents the lung from being compressed by abdominal pressure. The increase in transpulmonary pressure following a PEEP increase was closely related to the increase in PEEP, indicating that lung compliance can be calculated from the ratio of the change in end-expiratory lung volume and the change in PEEP, ΔEELV/ΔPEEP.

Positive end-expiratory pressure-induced changes in end-expiratory lung volume measured by spirometry and electric impedance tomography.

BACKGROUND: A bedside tool for monitoring changes in end-expiratory lung volume (ΔEELV) would be helpful to set optimal positive end-expiratory pressure (PEEP) in acute lung injury/acute respiratory distress syndrome patients. The hypothesis of this study was that the cumulative difference of the inspiratory and expiratory tidal volumes of the first 10 breaths after a PEEP change accurately reflects the change in lung volume following a PEEP alteration. METHODS: Changing PEEP induces lung volume changes, which are reflected in differences between inspiratory and expiratory tidal volumes measured by spirometry. By adding these differences with correction for offset, for the first 10 breaths after PEEP change, cumulative tidal volume difference was calculated to estimate ΔEELV(VT) ((i-e)) . This method was evaluated in a lung model and in patients with acute respiratory failure during a PEEP trial. In patients, ΔEELV(VT) ((i-e)) were compared with simultaneously measured changes in lung impedance, by electric impedance tomography (EIT), using calibration vs. tidal volume to estimate changes in ΔEELV(EIT) . RESULTS: In the lung model, there was close correlation (R(2) = 0.99) between ΔEELV(VT) ((i-e)) and known lung model volume difference, with a bias of -4 ml and limits of agreement of 42 and -50 ml. In 12 patients, ΔEELV(EIT) was closely correlated to ΔEELV(VT) ((i-e)) (R(2) = 0.92), with mean bias of 50 ml and limits of agreement of 131 and -31 ml. Changes in EELV estimated by EIT (ΔEELV(EIT) ) exceeded measurements by spirometry (ΔEELV(VT) ((i-e)) ), with 15 (±15)%. CONCLUSIONS: We conclude that spirometric measurements of inspiratory-expiratory tidal volumes agree well with impedance changes monitored by EIT and can be used bedside to estimate PEEP-induced changes in EELV.