Helmet continuous positive airway pressure for patients' transport using a single oxygen cylinder: A bench study

BACKGROUND

Continuous positive airway pressure (CPAP) is frequently used to treat patients with acute respiratory failure in out-of-hospital settings. Compared to a facemask, the helmet has many advantages for the patient but requires a minimum gas flow of 60 L/min to avoid CO2 rebreathing. The aim of the present bench study was to evaluate the performance of four Venturi devices, connected to a single oxygen cylinder, in delivering helmet-CPAP with clinically relevant gas flow, fraction of inspired oxygen (FiO2), and positive end-expiratory pressure (PEEP) values.

METHODS

Three double-inlet Venturi systems (EasyVent, Ventuplus, Compact-HAR) were connected to full 5-L oxygen cylinders using a double flowmeter, and their oxygen requirements to reach different setups (flow 60-80 L/min; FiO2 0.4-0.5-0.6, PEEP 7.5-10-12.5 cmH2O) were tested. The fourth Venturi system (O2-MAX) was directly attached to the tank, and the flow and FiO2 delivered at preset FiO2 0.3 and 0.6 were recorded. The runtime of the cylinder was assessed.

RESULTS

EasyVent, Ventuplus, and O2-MAX were able to deliver helmet-CPAP with clinically useful setups when connected to a single oxygen cylinder, while Compact-HAR did not. The runtime of the cylinders ranged between 28 and 60 minutes according to the preset flow and FiO2. The delivered gas flow decreased slowly and linearly with the drop in cylinder pressure until its exhaustion.

CONCLUSIONS

Helmet-CPAP might be provided using portable Venturi systems connected to an oxygen cylinder, but not all of them are able to deliver it. The use of a double flowmeter allows delivery of both high flow and high FiO2 when double-inlet Venturi systems are used. Due to the flow drop observed during the cylinder consumption, a flow >60 L/min should be set when helmet-CPAP is started. Considering the flow drop phenomenon, the estimated duration of the tank runtime can be used with a margin of safety when planning patient transport.

Resting heart rate and arterial stiffness: a longitudinal prospective study in a population of hypertensive patients

Background

The role of resting Heart Rate on the progression of arterial stiffness has not yet been extensively evaluated. The aim of this study is to investigate the relationship between resting HR and baseline arterial stiffness (evaluated by cfPWV) as well as its progression in a population of hypertensive patients over a 3.7 years follow-up period.

Methods

We enrolled 572 hypertensive outpatients 18–80 aged, followed by one hospital in Northern Italy. Anamnestic, clinical and laboratory data, BP and cfPWV were assessed at baseline and after a median follow-up time of 3.7±0.5 years

Results

At baseline the mean age was 53.9±12.7 years, SBP and DBP were 141.2±17.8 and 86.5±10.5 mmHg, HR was 65.6±10.9 bpm and PWV was 8.6±2.0 m/s. Despite an improvement in BP values (from 141.2/86.5 to 132.6/79.2 mmHg, p<0.001), during follow-up, PWV increased (ΔPWV 0.5±2.2 m/s). In patients with a ΔHR above as compared to those under the median value (9 bpm), ΔPWV was significantly higher (0.82±2.22 vs. 0.27±2.25 m/s, p=0.003). At multivariate analysis, HR was among the significant determinants of both baseline PWV and its progression (β = 0.031, p<0.001). Furthermore, ΔHR was a significant determinant of ΔPWV (β = 0.019; p=0.017).

Conclusions

in hypertensive patients there is a significant relationship between basal resting HR and basal PWV as well as between the increase of HR and the increase of PWV during the follow-up period. Beyond age and BP, resting HR must be considered as an independent determinant of arterial stiffness. This represents a possible mechanism through which HR contributes to the increase in CV risk.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Niguarda Hospital, Milan, Italy

C68 RESTING HEART RATE AND ARTERIAL STIFFNESS: A LONGITUDINAL PROSPECTIVE STUDY IN A POPULATION OF HYPERTENSIVE PATIENTS

Objective

The role of resting Heart Rate on the progression of arterial stiffness has not yet been extensively evaluated. The aim of this study is to investigate the relationship between resting HR and baseline arterial stiffness (evaluated by cfPWV) as well as its progression in a population of hypertensive patients over a 3.7 years follow–up period.

Methods

We enrolled 572 hypertensive outpatients 18–80 aged, followed by the Hypertension Unit of St. Gerardo Hospital (Monza, Italy). Anamnestic, clinical and laboratory data, BP and cfPWV (complior) were assessed at baseline and after a median follow–up time of 3.7 ± 0.5 years.

Results

At baseline the mean age was 53.9 ± 12.7 years, SBP and DBP were 141.2 ± 17.8 and 86.5 ± 10.5 mmHg, HR was 65.6 ± 10.9 bpm and PWV was 8.6 ± 2.0 m/s. Despite an improvement in BP values (from 141.2/86.5 to 132.6/79.2 mmHg, p < 0.001), during follow–up, PWV increased (ΔPWV 0.5 ± 2.2 m/s). In patients with a ΔHR above as compared to those under the median value (9 bpm), ΔPWV was significantly higher (0.82 ± 2.22 vs. 0.27 ± 2.25 m/s, p = 0.003). At multivariate analysis, HR was among the significant determinants of both baseline PWV and its progression (β = 0.031, p < 0.001). Furthermore, ΔHR was a significant determinant of ΔPWV (β = 0.019; p = 0.017).

Conclusions

In hypertensive patients there is a significant relationship between basal resting HR and basal PWV as well as between the increase of HR and the increase of PWV during the follow–up period. Beyond age and BP, resting HR must be considered as an independent determinant of arterial stiffness. This represents a possible mechanism through which HR contributes to the increase in CV risk.

P364 IMPORTANCE OF URIC ACID THRESHOLD IN ITS CORRELATION WITH METABOLIC SYNDROME

Background

The relationship between Hyperuricemia and Cardiovascular risk has been established but whether or not a correlation between Serum Uric Acid (SUA) and Metabolic Syndrome (MS) exists is still a matter of debate. Indeed whether SUA level is part of MS diagnosis or just a pure marker of an unfavourable metabolic profile has not been demonstrated. Besides it’s unknown whether SUA’s addition to MS definition makes a difference in terms of prognosis. In our study we focused on evaluating in a group of hypertensive patients, the correlation between MS diagnosis and SUA defined with two different cut–off: 1) ≥6 mg/dL for women and ≥7 for men (classic cut–off); 2) >5.6 mg/dL for both sexes (recently proposed by the URRAH Project).

Methods

We enrolled 473 Hypertensive patients followed by the Hypertension Unit of San Gerardo Hospital (Monza, Italy), in which SUA was measured. Patients with Hyperuricemia were identified according to the two different thresholds. NCEP–ATP–III criteria were used for diagnosis of MS.

Results

MS was diagnosed in 33.6% while Hyperuricemia was found in 14.8% of subjects according to the traditional cut–off and 35.9% according to URRAH study’s cut–off. Hyperuricemia and MS coexist in 9.7% (traditional cut–off) and 17.3% (URRAH’s threshold) of the population. Hyperuricemia was more frequent in MS than in non–MS subjects (29 vs 7.6%, p–value<0.0001 for cut–off 6/7 mg/dL and 51.6 vs 28.0%, p–value<0.0001 for cut–off 5.6 mg/dL). Linear regression models showed that SUA is related to MS diagnosis (β = 1.597, p–value<0.0001). At logistic analysis Hyperuricemia was strongly related to MS when defined by the HURRAH‘s cut–off (OR = 0.303, p–value<0.0001). The same relation is weak, although significan, when Hyperuricemia was defined by the classic cut–off (OR = 0.182, p–value<0.0001).

Conclusions

Hyperuricemia is related with MS diagnosis especially when defined by the recently defined cut–off of 5.6 mg/dL.

Metabolic syndrome is related to vascular structural alterations but not to functional one both in hypertensives and healthy subjects

Background

Metabolic Syndrome (MS) has been related to an impairment in arterial structural and functional properties with heterogeneous results.

Purpose

In this study we focused on the effects of MS on arterial carotid-femoral Pulse Wave Velocity (PWV) and common carotid Intima Media Thickness (IMT) in two different populations, one of hypertensive patients and one of healthy controls.

Methods

We enrolled 816 consecutive hypertensive (HT) and 536 healthy controls. Vascular structural (IMT) and functional (PWV) properties were evaluated. NCEP-ATP-III criteria were used for diagnosis of MS.

Results

MS was diagnosed in 26.9% and 6.9% in hypertensive and control subjects, respectively. PWV was similar in controls with and without MS (7.7±1.9 vs 7.6±1.1 m/s, p=0.69), while IMT was higher in controls with than those without MS (0.64±0.18 vs 0.57±0.13 mm, p=0.02). Hypertensives with MS were older (57.9±12.2 vs 52.7±14.1 years, p<0.001) and showed higher PWV (9.0±2.3 vs 8.4±2.1 m/s, p=0.001) and IMT (0.72±0.22 vs 0.65±0.17 mm, p<0.001) than those without MS, however at the age-adjusted analysis only the difference in IMT was confirmed (p=0.007). Regression models showed that MS was an independent determinant of IMT in both controls (β=0.08, p=0.03) and hypertensives (β=0.08, p=0.01), but not of PWV either in controls (β=0.006, p=0.886 and β=0.04, p=0.19, respectively).

Conclusions

The main finding of our work is that MS is a significant determinant of IMT while this is not the case for PWV. This result has been confirmed both in hypertensive subjects and in healthy controls.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): ASST Grande Ospedale Metropolitano Niguarda

Hyperuricemia and Risk of Cardiovascular Outcomes: The Experience of the URRAH (Uric Acid Right for Heart Health) Project

The latest European Guidelines of Arterial Hypertension have officially introduced uric acid evaluation among the cardiovascular risk factors that should be evaluated in order to stratify patient's risk. In fact, it has been extensively evaluated and demonstrated to be an independent predictor not only of all-cause and cardiovascular mortality, but also of myocardial infraction, stroke and heart failure. Despite the large number of studies on this topic, an important open question that still need to be answered is the identification of a cardiovascular uric acid cut-off value. The actual hyperuricemia cut-off (> 6 mg/dL in women and 7 mg/dL in men) is principally based on the saturation point of uric acid but previous evidence suggests that the negative impact of cardiovascular system could occur also at lower levels. In this context, the Working Group on uric acid and CV risk of the Italian Society of Hypertension has designed the Uric acid Right for heArt Health project. The primary objective of this project is to define the level of uricemia above which the independent risk of CV disease may increase in a significantly manner. In this review we will summarize the first results obtained and describe the further planned analysis.

Impact of body mass index and waist circumference on the cardiovascular risk and all-cause death in a general population: data from the PAMELA study

BACKGROUND AND AIMS

Elevated values of body mass index (BMI) and waist circumference (WC) are associated with an augmented cardiovascular (CV) risk. It is debated, however, whether and to what extent this depends on the body fat increase 'per se' or on the related cardiometabolic alterations.

METHODS AND RESULTS

In 2005 subjects randomly selected from the general population of Monza (Italy), we assessed BMI, WC, office, home and 24 h blood pressure (BP), heart rate and metabolic variables. The impact of BMI and WC on the incidence of CV events, CV and all-cause mortality was estimated during a 148-month follow-up. Progressively higher values of BMI and WC were associated with a progressive increase in office, home and 24 h BP and in erratic BP variability (P < 0.0001 for trend). Metabolic variables were directly and significantly (P < 0.0001) related to BMI and WC, while an inverse significant relationship was detected with high-density lipoprotein (HDL)-cholesterol. The incidence of CV events, CV and all-cause deaths increased progressively from the lowest to the highest quintile of BMI and WC (P for trend always <0.005). Baseline BMI and WC higher by respectively 1 kg m⁻² and 1 cm were associated with an increased risk of CV events, CV and all-cause death by 8%, 12% and 7% (for baseline BMI) and 4%, 5% and 4% (for baseline WC), respectively. After adjustment for confounders, only the increased risk of CV death related to higher baseline BMI remained significant (hazard ratio (HR) 1.062, confidence interval (CI) 95% 1.003-1.126, P < 0.05).

CONCLUSION

The adverse prognostic impact of the accumulation of body fat is mediated by the associated haemodynamic and metabolic alterations. Baseline values of BMI, however, are an independent predictor of CV mortality.

A minimally invasive single incision anterior approach for total hip arthroplasty: Early results in 49 cases

A modified and limited Smith Petersen approach was used for prosthetic hip replacement. The exposure of the proximal femur required the use of a traction table. We operated on 49 patients: 15 of them underwent cemented bipolar hemiarthroplasty, and 34 had a total hip arthroplasty. Skin incision ranged from 6 to 11 cm (average 7.8 cm). Patients subjective grading was evaluated according to a pain scale (0-10); early functional outcome was rated on postoperative days two, seven and 30 according to a functional scale of active flexion and abduction. Average active flexion on the second postoperative day was 68.4, and active abduction 14.7. Progressive increment of average active flexion and abduction was observed on day 7 (78.7 flexion - 22.3 abduction) and day 30 (88.4 flexion 29.2 abduction). All patients were allowed progressive weight-bearing depending on their postoperative pain. Most of them were fully weight bearing from the first day. This surgical approach, characterized by preservation of the muscular insertions, is associated with reduced postoperative pain and fast functional recovery. (Hip International 2004; 14: 233-8).

Alterations of cardiac structure in patients with isolated office, ambulatory, or home hypertension: Data from the general population (Pressione Arteriose Monitorate E Loro Associazioni [PAMELA] Study)

BACKGROUND

The prevalence and clinical significance of isolated office (or white coat) hypertension is controversial, and population data are limited. We studied the prevalence of this condition and its association with echocardiographic left ventricular mass in the general population of the PAMELA (Pressione Arteriose Monitorate E Loro Associazioni) Study.

METHODS AND RESULTS

The study involved a large, randomized sample (n=3200) representative of the Monza (Milan) population, 25 to 74 years of age. Participants in the study (64% of the sample) underwent measurements of office, home, 24-hour ambulatory blood pressure, and echocardiography. Isolated office hypertension was defined as systolic or diastolic values >/=140 mm Hg or >/=90 mm Hg, respectively. Home and ambulatory normotension were defined according to criteria previously established from the PAMELA Study, for example, <132/83 mm Hg (systolic/diastolic) for home and 125/79 mm Hg for 24-hour average blood pressure. Treated hypertensive subjects were excluded from analysis that was made on a total of 1637 subjects. Depending on normotension being established on systolic or diastolic blood pressure measured at home or over 24 hours, the prevalence of isolated office hypertension ranged from 9% to 12%. In these subjects, left ventricular mass index was greater (P<0.01) than in subjects with normotension both in and outside the office. This was the case also for prevalence of left ventricular hypertrophy. Left ventricular mass index and hypertrophy were similarly greater in subjects found to have normal office but elevated home or ambulatory blood pressure ( approximately 10% of the population).

CONCLUSIONS

Isolated office hypertension has a noticeable prevalence in the population and is accompanied by structural cardiac alterations, suggesting that it is not an entirely harmless phenomenon. This is the case also for the opposite condition, that is, normal office but elevated home or ambulatory blood pressure, which implies that limiting blood pressure measurements to office values may not suffice in identification of subjects at risk.

Seasonal variations in home and ambulatory blood pressure in the PAMELA population. Pressione Arteriose Monitorate E Loro Associazioni

OBJECTIVE

Clinic blood pressure values are known to change according to seasonal influences. We therefore examined home and 24 h ambulatory blood pressure values to determine whether these measurements are also affected by the seasons.

DESIGN AND METHODS

In 2051 subjects of the Pressione Arteriose Monitorate E Loro Associazioni (PAMELA) study, we measured clinic (sphygmomanometric measurements), home (semi-automatic device) and ambulatory (Spacelabs 90207) systolic blood pressure, diastolic blood pressure and heart rate. Because the overall sample was evenly distributed over each month (except August), we were able to make a cross-sectional determination of whether the values differed between seasons. The corresponding heart rates were also evaluated.

RESULTS

As expected, summer was associated with the lowest clinic blood pressure and winter with the highest, and this was the case also for home and 24 h average blood pressure, although seasonal differences in the latter were less pronounced. Seasonal clinic, home and ambulatory blood pressure patterns were similar for normotensive subjects (n = 1152), untreated hypertensives (n = 540) and treated hypertensives (n = 359). Heart rate values did not differ by season.

CONCLUSIONS

Seasonal influences on blood pressure are not limited to conventional measurements but characterize daily values as well. These effects are visible in both normal and elevated blood pressure values, regardless of the effect of antihypertensive drugs. This has implications both for the clinician and for studies aimed at evaluating the effects of antihypertensive treatment.

Ambulatory blood pressure in air traffic controllers

Conflicting reports exist as to whether air traffic controllers (ATC) have an increase in blood pressure (BP) and prevalence of hypertension because of the stressful nature of their job. We have addressed the issue in male ATC working at the Linate airport of Milan. A total of 80 ATC participated, and the 24 h blood pressure monitoring was obtained during two working shifts separated by one night of rest. Blood pressure was measured conventionally and by 24 h ambulatory monitoring; data were compared with those of an age matched male sample three times as large, selected from the data of the Studio delle Pressioni Ambulatoriali delle Loro Associazioni (PAMELA), ie, a large sample representative of the population of the nearby town of Monza. Treated hypertensive subjects were excluded from both groups. Conventional diastolic BP and heart rate were similar in ATC and controls, whereas conventional systolic BP was significantly greater in the former than in the latter group. No difference, however, was seen between ATC and controls as far as ambulatory BP and heart rate were concerned; namely, 24 h, day, and night average systolic BP, and diastolic BP and heart rate were similar in the two groups. Thus daily life BP is not increased in ATC. This may result from the fact that, being a highly selected group with suitable training, these subjects adequately cope with the stress inherent to the job.

Combined effects of hypertension and hypercholesterolemia on radial artery function

Compliance and distensibility of middle-sized conduit arteries are increased in hypertension and reduced in hypercholesterolemia. Despite their frequent association in the same individual, the combined effect of these two conditions on arterial mechanical properties is unknown. We studied four groups of age- and sex-matched subjects: 10 normotensive normocholesterolemic subjects, 10 mild hypertensive normocholesterolemic subjects, 10 mild hypercholesterolemic normotensive subjects, and 10 mild hypertensive and mild hypercholesterolemic subjects. We measured radial artery diameter by an echotracking device and beat-to-beat blood pressure from an ipsilateral finger. Compliance-pressure and distensibility-pressure curves were derived by Langewouters' formula. Between-group comparisons were made by calculating for both compliance and distensibility the integral of the area under the portion of the curve common to the four groups ("isobaric" compliance and distensibility). Blood pressure was similarly elevated in the two hypertensive groups, and serum cholesterol was similarly elevated in the two hypercholesterolemic groups. Compared with values in normotensive normocholesterolemic subjects, isobaric compliance and distensibility were greater in hypertensive normocholesteroclemic (+38% and 47%, respectively) and smaller in normotensive hypercholesterolemic (-6% and -23%) subjects. However, when both hypertension and hypercholesterolemia were present, isobaric compliance and isobaric distensibility were significantly reduced (-26% and -18%, P < .05). Therefore, hypercholesterolemia reverses the effect of hypertension on arterial compliance and causes arterial stiffening, as when present alone.

Extensimetric monitoring of healing in the treatment with the Ilizarov apparatus. A multicenter clinical trial

The results of a multicentric review are reported using the extensimetric instrumentation applied to the Ilizarov device. This clinical trial the follows same theoretical and experimental preliminary studies, outlines the advantages and current limits of the method, and sets the bases for further clinical and experimental research.

[The value of ultrasound for correction of clinical diagnostic errors in soft tissue tumors]

In doubtful clinical diagnosis, ultrasound investigation may represent a workable diagnostic means in revealing the nature of soft tissue alterations, as will be demonstrated by 6 clinical examples; in all cases a wrong clinical diagnosis delayed the necessary therapy and possibly deteriorated the prognosis of disease. In these patients correction of the clinical diagnosis was of decisive importance for consecutive diagnostics and therapy.

[Vacuum sealing as treatment of soft tissue damage in open fractures]

In 1992, 15 of 152 patients with open fractures were treated with vacuum sealing. Drainage tubes are inserted into polyvinyl foam, which is used to fill in the wound or tissue defect. Polyvinyl foam and adjacent skin are covered with a transparent polyurethane dressing which is impermeable to bacteria. The connection of the drainage tubes to a suction device, such as vacuum bottles, produces negative pressure in the polyvinyl foam, which means a high-contact zone of the foam-wound interface. This results in efficient cleaning and conditioning of the wound, with marked proliferation of granulation tissue. Bone infection did not occur in any of our 15 patients; 1 patient sustained a soft tissue infection due to an insufficient sealing technique. When the correct technique was applied the infection cleared up.

Comparison of the new alpha 1-blocker alfuzosin with propranolol as first-line therapy in hypertension

The new alpha 1-blocker alfuzosin was compared with propranolol as monotherapy for hypertension in a double-blind, parallel group study of 8-week duration in 40 patients with essential hypertension. The patients (11 males, 29 females; mean age 47.8 +/- 2.2 years in the alfuzosin group and 46.6 +/- 2.4 years in the propranolol group) randomly received either alfuzosin from 2.5 mg b.i.d. up to 10 mg b.i.d. or propranolol from 40 mg b.i.d. up to 160 mg b.i.d. according to an individualized dose-titration schedule. The two groups were comparable with respect to disease history, cardiovascular risk factors, concomitant diseases, previous treatments and end-placebo blood pressure and heart rate values. Four patients did not complete the study, two patients in the alfuzosin group: one patient because of postural hypotension and the second one because of breast cancer; and two patients in the propranolol group: one patient for inefficacy and the second one lost to follow-up. At the end of the 8-week trial the mean daily doses were 12.2 +/- 0.61 mg and 196 +/- 9.82 mg for alfuzosin and propranolol, respectively. The antihypertensive effects of the two drugs were comparable. Upright and supine blood pressures decreased significantly with both treatments from the second week on (P less than 0.001 for all BP values). At the end of the 8-week double-blind trial, 83% of alfuzosin patients and 67% of propranolol patients were normalized. The two treatments differed significantly with respect to their effect on heart rate. Alfuzosin did not induce marked changes in heart rate: only a slight increase was observed. In contrast, propranolol caused bradycardia, more marked in the upright position. Palpitations, headache, asthenia and orthostatic hypotension were reported in the alfuzosin group. Asthenia and decreased libido were reported in the propranolol group. These data prove that alfuzosin has antihypertensive effects equivalent to propranolol and it is an interesting agent for the therapy of essential hypertension. It can be used as a first agent at doses between 5 and 20 mg/day with satisfactory therapeutic response and without relevant side-effects.

Valgus-extension osteotomy for osteoarthritis of the hip. Indications and long-term results

We reviewed the results of 277 intertrochanteric valgus-extension osteotomies performed between 1973 and 1975 for primary or secondary osteoarthritis. The average age of the patients was 51 years and follow-up varied from 11 to 15 years. At the latest evaluation 67% of the hips were good or excellent on the Merle D'Aubigné scale. Better results were obtained in patients under 40 years of age with unilateral involvement and a mechanical (secondary) aetiology. An elliptical femoral head, minimal subluxation and an adequate pre-operative range of motion were also favourable. There was radiographic evidence of regression of the arthritic changes in 39% of the hips at final review. Valgus-extension osteotomy is effective for secondary osteoarthritis of the hip in selected younger patients, but not for those with primary hip disease or a poor range of movement.