Respiratory rate monitoring in ICU patients and healthy volunteers using electrical impedance tomography: a validation study.

Objective. The respiratory rate (RR) is considered one of the most informative vital signals. A well-validated standard for RR measurement in mechanically ventilated patient is capnography; a noninvasive technique for expiratory CO2measurements. Reliable RR measurements in spontaneously breathing patients remains a challenge as continuous mainstream capnography measurements are not available. This study aimed to assess the accuracy of RR measurement using electrical impedance tomography (EIT) in healthy volunteers and intensive care unit (ICU) patients on mechanical ventilation and spontaneously breathing post-extubation. Comparator methods included RR derived from both capnography and bioimpedance electrocardiogram (ECG) measurements.Approach. Twenty healthy volunteers wore an EIT belt and ECG electrodes while breathing through a capnometer within a 10-40 breaths per minute (BPM) range. Nineteen ICU patients underwent similar measurements during pressure support ventilation and spontaneously breathing after extubation from mechanical ventilation. Stable periods with regular breathing and no artefacts were selected, and agreement between measurement methods was assessed using Bland-Altman analysis for repeated measurements.Main result. Bland-Altman analysis revealed a bias less than 0.2 BPM, with tight limits of agreement (LOA) ±1.5 BPM in healthy volunteers and ventilated ICU patients when comparing EIT to capnography. Spontaneously breathing ICU patients had wider LOA (±2.5 BPM) when comparing EIT to ECG bioimpedance, but gold standard comparison was unavailable. RR measurements were stable for 91% of the time for capnography, 68% for EIT, and 64% of the ECG bioimpedance signals. After extubation, the percentage of stable periods decreased to 48% for EIT signals and to 55% for ECG bioimpedance.Significance. In periods of stable breathing, EIT demonstrated excellent RR measurement accuracy in healthy volunteers and ICU patients. However, stability of both EIT and ECG bioimpedance RR measurements declined in spontaneously breathing patients to approximately 50% of the time.

Analysis and applications of respiratory surface EMG: report of a round table meeting.

Surface electromyography (sEMG) can be used to measure the electrical activity of the respiratory muscles. The possible applications of sEMG span from patients suffering from acute respiratory failure to patients receiving chronic home mechanical ventilation, to evaluate muscle function, titrate ventilatory support and guide treatment. However, sEMG is mainly used as a monitoring tool for research and its use in clinical practice is still limited-in part due to a lack of standardization and transparent reporting. During this round table meeting, recommendations on data acquisition, processing, interpretation, and potential clinical applications of respiratory sEMG were discussed. This paper informs the clinical researcher interested in respiratory muscle monitoring about the current state of the art on sEMG, knowledge gaps and potential future applications for patients with respiratory failure.

Optimising the acquisition and retention of heat acclimation.

Heat acclimation (HA) often starts in a moderately hot environment to prevent thermal overload and stops immediately prior to athletic activities. The aims of this study were (1) to establish whether acclimation to a moderately hot climate is sufficient to provide full acclimation for extreme heat and (2) to investigate the physiological responses to heat stress during the HA decay period. 15 male subjects exercised for 9 consecutive days at 26° C Wet Bulb Globe Temperature (WBGT) and 3 days at 32° C WBGT on a cycle ergometer for up to 2 h per day and repeated the exercise 3, 7 and 18 days later in 26° C WBGT. Rectal temperature (T (re)) and heart rate (HR) were measured during 60 min of steady state exercise (∼45% of maximum oxygen uptake). During days 1-9, end-exercise T (re) was reduced from 38.7±0.1 to a plateau of 38.2±0.1° C (p<0.05), HR was reduced from 156±10 to 131±11 bpm (p<0.05). No changes in HR and T (re) occurred during the 3 days in the very hot environment. However, T (re) during rest and exercise were significantly lower by 0.4-0.5° C after HA compared with day 9, suggesting that heat acclimation did not decay but resulted in further favourable adaptations.

The impact of margin status in breast-conserving therapy for lobular carcinoma is age related.

PURPOSE: The aim is to look at the impact of margin status and outcome of invasive lobular carcinoma (ILC) treated with breast-conserving therapy (BCT). METHODS: This manuscript describes an analysis on 330 BCT in 318 patients with ILC. RESULTS: The 12-year local relapse free survival (LRFS) is 89%. In multivariate analysis, positive margin status, age>50 years, contra lateral breast cancer, and adjuvant systemic therapy were significant predictors of local relapse free survival. In a separate analysis limited to a positive margin for invasive carcinoma or carcinoma in situ, only a positive margin for invasive carcinoma was a significant predictor of local relapse free survival. This was limited to women

Fos expression in the midbrain periaqueductal grey after trigeminovascular stimulation.

There is an accumulating body of evidence suggesting that the periaqueductal grey (PAG) is involved in the pathophysiology of migraine. Positron emission tomography (PET) studies in humans have shown that the caudal ventrolateral midbrain, encompassing the ventrolateral PAG, has activations during migraine attacks. The PAG may well be involved not only through the descending modulation of nociceptive afferent information, but also by its ascending projections to the pain processing centres of the thalamus. In this study the intranuclear oncogene protein Fos was used to mark cell activation in the PAG following stimulation of the trigeminally-innervated superior sagittal sinus (SSS) in both cats and in nonhuman primates (Macaca nemestrina). Fos expression in the PAG increased following stimulation to a median of 242 cells (interquartile range 236-272) in the cat and 155 cells (range 104-203) in the monkey, compared with control levels of 35 cells (21-50) and 26 cells (18-33), respectively. Activation was predominantly in the ventrolateral area of the caudal PAG suggesting that the PAG is involved following trigeminally-evoked craniovascular pain.

Cost-saving through microscopy-based versus presumptive diagnosis of malaria in adult outpatients in Malawi.

The cost implications of changing from a policy of presumptive diagnosis to one of microscopy-based diagnosis in the management of uncomplicated malaria in an urban hospital adult outpatient clinic in Malawi were studied. Costs were measured in three separate weeks during the rainy season. In weeks I and II all uncomplicated malaria cases were treated on the basis of a presumptive diagnosis. In week II, blood films were taken but the results were not made available and did not affect drug dispensing. In week III, antimalarial drugs were restricted to parasitaemic patients. In week I, a total of 7216 prescriptions were written and dispensed, of which 2883 (39.9%) were for antimalarial drugs. The proportion of antimalarial prescriptions fell to 1171/5556 (21.1%) in week II and 357/5377 (6.6%) in week III. We estimate annual savings from microscopy-directed treatment in this setting to be 52,000 Malawi kwacha (US$ 14,000). This represents 3% of the annual drugs budget for the hospital, and is large enough to justify a change in policy.

Response to indomethacin and hydrochlorothiazide in nephrogenic diabetes insipidus.

Four boys with classical nephrogenic diabetes insipidus have been treated by indomethacin, by hydrochlorothiazide, and by the combination of indomethacin and hydrochlorothiazide. Hydrochlorothiazide treatment was slightly more effective than indomethacin treatment in reducing the urine volume and increasing the urine osmolality. The combination of indomethacin and hydrochlorothiazide appeared to be additive and especially helpful in infants and young children before the autonomy of drinking.