Pekka Meriläinen

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BACKGROUND Inadequate analgesia during general anaesthesia may present as undesirable haemodynamic responses. No objective measures of the adequacy of analgesia exist. We aimed at developing a simple numerical measure of the level of surgical stress in an anaesthetized patient. METHODS Sixty and 12 female patients were included in the development and(More)
We used near-infrared spectroscopy (NIRS) to study responses to speech and music on the auditory cortices of 13 healthy full-term newborn infants during natural sleep. The purpose of the study was to investigate the lateralization of speech and music responses at this stage of development. NIRS data was recorded from eight positions on both hemispheres(More)
Near-infrared spectroscopy (NIRS) is a method for noninvasive estimation of cerebral hemodynamic changes. Principal component analysis (PCA) and independent component analysis (ICA) can be used for decomposing a set of signals to underlying components. Our objective is to determine whether PCA or ICA is more efficient in identifying and removing scalp blood(More)
Near-infrared spectroscopy (NIRS) is a non-invasive technique for estimating cortical concentration changes of oxy(Δ[HbO2]), deoxy(Δ[HbR]), and total (Δ[HbT]=Δ[HbO2] +Δ[HbR]) hemoglobin [1, 2]. Cortical Δ[HbT] is commonly used as an indicator of cerebral blood volume (CBV) changes. Obstructive sleep apnea (OSA) is characterized by apneas (pause in breathing(More)
BACKGROUND Dexmedetomidine, a selective alpha(2)-adrenoceptor agonist, induces a unique, sleep-like state of sedation. The objective of the present work was to study human electroencephalogram (EEG) sleep spindles during dexmedetomidine sedation and compare them with spindles during normal physiological sleep, to test the hypothesis that dexmedetomidine(More)
It is a well-known fact that smoking is associated with a reduction in exhaled nitric oxide (NO) levels. There is, however, limited knowledge relating to the smoking-induced changes in production or exchange of NO in different compartments of the airways. This study comprised 221 adult subjects from the European Community Respiratory Health Survey II, who(More)
During the last year exhaled nitric oxide (NO) has been proposed as a marker of airway inflammation. More knowledge of the production and transfer of this molecule are needed in order for NO analysis to become a clinical tool. This was the aim of the study. Exhaled NO values from multiple flow rates were used to model alveolar NO, transfer rate and tissue(More)
We present the characterization of dry spiked biopotential electrodes and test their suitability to be used in anesthesia monitoring systems based on the measurement of electroencephalographic signals. The spiked electrode consists of an array of microneedles penetrating the outer skin layers. We found a significant dependency of the(More)
The recommended method to measure exhaled nitric oxide (NO) cannot reveal the source of NO production. We applied a model based on the classical Fick's first law of diffusion to partition NO in the lungs. The aim was to develop a simple and robust solution algorithm with a data quality control feature, and apply it to patients with known alterations in(More)