Non-invasive ventilation in neuromuscular diseases: should we use higher levels of ventilatory support?

PURPOSE: In patients with COPD, one of the leading indications for domiciliary non-invasive ventilation (NIV), a major paradigm shift has been observed over the past decade in the method for adjusting NIV settings, with the use of sufficient ventilatory support to achieve a significant reduction in PaCO2. Whether this approach may be relevant to other populations, especially slowly progressive neuromuscular diseases (NMD), is unknown. METHODS: This study was conducted as a post hoc analysis from a previously published randomized controlled trial (NCT03458507). Patients with NMD treated with domiciliary NIV were stratified according to the level of ventilatory support: high-level tidal volume (HLVT; mL/kg of predicted body weight [PBW]) or high-level pressure support (HLPS), defined as a value above median value of the whole population (> 6.8 mL/kgPBW or 9.0 cmH2O, respectively). Primary outcome was mean nocturnal transcutaneous CO2 pressure (PtcCO2). Secondary outcomes included adherence to NIV, leaks, and side effects. RESULTS: Of a total of 26 patients, 13 were exposed to HLVT, with significantly lower nocturnal PtcCO2 (respectively 40.5 ± 4.2 vs. 46.3 ± 3.9 mmHg, p = 0.002). A linear correlation between VT (mL/kgPBW) and mean nocturnal PtcCO2 was evidenced (r = - 0.59, 95%CI [- 0.80; - 0.25], p = 0.002). No significant impact of HLVT was found on secondary outcomes. CONCLUSION: Despite the lack of power of this post hoc analysis, our results suggest that higher levels of ventilatory support are correlated with lower PtcCO2 in patients with NMD. Further studies are desirable to assess the extent to which the level of assistance influences PaCO2 evolution in patients with slowly progressive NMD, as well as in restrictive thoracic disorders.

Mismatch negativity to predict subsequent awakening in deeply sedated critically ill patients.

BACKGROUND: Mismatch negativity (MMN) is the neurophysiological correlate of cognitive integration of novel stimuli. Although MMN is a well-established predictor of awakening in non-sedated comatose patients, its prognostic value in deeply sedated critically ill patients remains unknown. The aim of this prospective, observational pilot study was to investigate the prognostic value of MMN for subsequent awakening in deeply sedated critically ill patients. METHODS: MMN was recorded in 43 deeply sedated critically ill patients on Day 3 of ICU admission using a classical 'odd-ball' paradigm that delivers rare deviant sounds in a train of frequent standard sounds. Individual visual analyses and a group level analysis of recordings were performed. MMN amplitudes were then analysed according to the neurological status (awake vs not awake) at Day 28. RESULTS: Median (inter-quartile range) Richmond Assessment Sedation Scale (RASS) at the time of recording was -5 (range, from -5 to -4.5). Visual detection of MMN revealed a poor inter-rater agreement [kappa=0.17, 95% confidence interval (0.07-0.26)]. On Day 28, 30 (70%) patients had regained consciousness while 13 (30%) had not. Quantitative group level analysis revealed a significantly greater MMN amplitude for patients who awakened compared with those who had not [mean (standard deviation) = -0.65 (1.4) vs 0.08 (0.17) µV, respectively; P=0.003). CONCLUSIONS: MMN can be observed in deeply sedated critically ill patients and could help predict subsequent awakening. However, visual analysis alone is unreliable and should be systematically completed with individual level statistics.

[Selective and non-invasive monitoring of the posterior columns and pyramidal tract during surgery of the spine and spinal cord]. / Monitorage non invasif et sélectif des cordons postérieurs et de la voie pyramidale pendant les chirurgies du rachis et de la moelle épinière.

For intra-operative neurophysiological monitoring during spine and spinal cord surgery, the challenge is to detect, in real-time, the occurrence of neurological impairment at onset in order to remedy the problem as quickly as possible before it becomes definitely acquired and irreversible. The past three decades were marked by considerable technical progress. Feasibility and reliability have now reached a very high level. A multimodal approach combining simultaneous monitoring of somatosensory and motor pathways has enabled a considerable decline in the rate of false negatives reported in the 80s when somatosensory evoked potentials (SSEP) were monitored alone. Several methods of monitoring are described in the literature. Combining transcranial electric stimulation of muscle motor evoked potentials (mMEP) and cortical SSEP allows non-invasive and selective monitoring of the posterior columns and pyramidal tract. One of the most widely used techniques internationally backed by a broad consensus within the International Society of Intra-operative Neurophysiology (ISIN), this technique remains exceptional in French-speaking countries. We expose here the methodological aspects for the readers of La Revue Neurologique.

Effect of manufacturer-inserted mask leaks on ventilator performance.

Most pressure-support devices use a single circuit with an exhalation port integrated in the mask. The aim of the current study was to compare the effects of masks having different manufacturer-inserted leaks on ventilator performance. We simulated chronic obstructive pulmonary disease and restrictive disease. Four ventilators (VENTImotion (Weinmann, Hamburg, Germany), VPAP III STA (ResMed, Saint Priest, France), Synchrony 2 (Respironics, Nantes, France) and Vivo 40 (Breas, Saint Priest)) were tested with the recommended masks and with the masks having the largest and smallest leaks. Tests were performed with pressure support levels of 10, 15 and 20 cmH(2)O. The in vivo evaluation compared two ventilators using recommended masks opposed in terms of exhaled port resistance. The ventilators were tested with their recommended mask, and after mask exchange. The mask with the largest leak induced auto-triggering and/or increased inspiratory-trigger sensitivity was the VENTImotion under both simulated conditions and VPAP III STA under the simulated obstructive-disease condition. The mask with the smallest leak-increased inspiratory-trigger delay was Synchrony 2 in the simulated obstructive-disease condition and increased rebreathing. The in vivo study confirmed the bench results. When switching to a mask that has a different leak, evaluation is needed to adjust trigger sensitivity and pressurisation level and to check the absence of rebreathing.

Relation between corset use and lung function postural variation in spinal cord injury.

Corsets are widely used to improve trunk stability in patients with spinal cord injury (SCI) and can improve respiratory function. The aim of the present study was to identify predictors of respiratory benefits from wearing a corset in SCI patients. In a prospective observational study, respiratory function was tested in the supine and upright seated position with and without a corset in 36 SCI patients who regularly used a corset. SCI patients who no longer used a corset were matched to users on sex, injury level and severity. Vital capacity (VC) did not differ between users and nonusers in the supine position. In users, contrary to nonusers, VC increased significantly in the supine position compared to the seated position (increase of 0.43+/-0.39 versus -0.05+/-0.32 L in nonusers; p<0.0001). Corset use was associated with a significant VC increase in the upright position (2.13+/-0.71 L without versus 2.41+/-0.69 L with the corset; p<0.001). The VC increase with the corset in the upright position correlated significantly with the VC increase induced by being supine, compared to sitting without the corset. The VC increase induced in SCI patients by lying supine may predict the effects of wearing a corset. The long-term effects of corset use should be evaluated.

[Factors associated with the type of mask used during nocturnal NIV in patients with neuromuscular disorders]. / Facteurs associés au masque de ventilation non invasive nocturne chez les patients neuromusculaires adultes.

In subjects with neuromuscular diseases (NMD), the choice of facemask is essential for successful long-term noninvasive ventilation (NIV). While nasal masks usually represent the first line of treatment, almost a third of our subjects with NMD use an oro-nasal interface. Factors associated with the choice of mask remain poorly understood. We provide an original analysis of a previous prospective, multi-centric, Franco-Belgian survey investigating the factors associated with the type of nocturnal mask used in 116 adult NMD subjects treated with NIV. In these patients oro-nasal mask use was more often associated with non-Duchenne muscular dystrophy, older subjects, higher body mass index, better upper limb autonomy allowing independent mask removal and shorter periods of ventilation. Controlled prospective studies are needed to compare the efficacy and tolerance of different interfaces in this specific population.

Sniff nasal inspiratory pressure in children with muscular, chest wall or lung disease.

Sniff nasal inspiratory pressure is proposed as a noninvasive test of inspiratory muscle strength. During this manoeuvre, the nasal pressure is supposed to reflect oesophageal pressure. The aim of the present study was to compare the nasal pressure with the oesophageal pressure during a maximal sniff in children with neuromuscular disease (NM, n = 78), thoracic scoliosis (n = 12) and cystic fibrosis (CF, n = 23). A significant correlation was observed between the sniff nasal and oesophageal pressure. The ratio of the sniff nasal/oesophageal pressure was lower in patients with CF (0.72+/-0.13) than in NM patients (0.83+/-0.17) or patients with thoracic scoliosis (0.86+/-0.10). In patients with CF and NM disease, this ratio was not correlated to age or spirometric data. The difference between the sniff oesophageal and nasal pressure exceeded 15 cm H(2)O in 17, 33 and 87% of the NM, thoracic scoliosis and CF patients, respectively. Sniff nasal pressure often underestimates the strength of inspiratory muscles in cystic fibrosis. Such an underestimation occurs more rarely in neuromuscular disease disorders and thoracic scoliosis. A normal value excludes inspiratory muscle weakness but a low value requires the measurement of the oesophageal pressure.

Effect of sleeping alone on sleep quality in female bed partners of snorers.

The aim of the present study was to objectively measure the effect of sleeping alone for one night on sleep quality in female bed partners of male snorers. Females complaining of poor sleep due to snoring by their bed partner and having no known hearing loss or snoring were included in a prospective multicentre cross-sectional study. 23 females underwent one polysomnography recording while sleeping with their bed partner and another while sleeping alone. Their sleep parameters were compared between the two nights. We excluded seven couples because the female partner snored for >10% of the sleep time (n = 6) or had obstructive sleep apnoea syndrome (n = 1). In the remaining 16 females, sleep time, sleep efficiency, arousal index and percentages of deep sleep (stages 3-4) and rapid eye movement (REM) sleep were not significantly different between the two nights. Percentages of light sleep (non-REM stage 2) and awakening index were lower when sleeping alone (p = 0.023 and p = 0.046, respectively). Sleep quality was decreased and sleep fragmentation increased in females sleeping with male snorers. Some females had unrecognised snoring. However, our data do not suggest that objective sleep quality improves substantially in the female nonsnoring partner when she sleeps alone for one night.

Tongue weakness is associated with respiratory failure in patients with severe Guillain-Barré syndrome.

OBJECTIVE: Swallowing impairment may worsen respiratory weakness and conduct to respiratory complications such as aspiration pneumonia in Guillain-Barré syndrome (GBS). We prospectively evaluate how tongue weakness could be associated to bulbar dysfunction and respiratory weakness in severe GBS patients. MEASUREMENTS AND MAIN RESULTS: Tongue strength, dysphagia and respiratory parameters were measured in 16 GBS patients at intensive care unit (ICU) admission and discharge and in seven controls. Tongue strength was decreased in the GBS patients compared with the controls. At admission, patients with dysphagia and those requiring mechanical ventilation (MV) had greater tongue weakness. All the patients with initial tongue strength <150 g required MV during ICU stay. Tongue strength correlated significantly with respiratory parameters. CONCLUSION: This study confirms the strong association between bulbar and respiratory dysfunction in GBS admitted to ICU. Tongue weakness may be present in GBS, especially during the phase of increasing paralysis, and resolves during the recovery phase. Tongue strength and indices of global and respiratory strength vary in parallel throughout the course of GBS. Further studies are needed to assess if, when used in combination with other respiratory tests, tongue strength measurement could contribute to identify patients at high risk for respiratory complications.

Performance of ventilators for noninvasive positive-pressure ventilation in children.

The aim of the present study was to evaluate the performance characteristics of all the ventilators proposed for home noninvasive positive-pressure ventilation in children in France. The ventilators (one volume-targeted, 12 pressure-targeted and four dual) were evaluated on a bench which simulated six different paediatric ventilatory patterns. For each ventilator, the quality of the inspiratory and expiratory trigger and the ability to reach and maintain the preset pressures and volumes were evaluated with the six patient profiles. The performance of the ventilators showed great variability, and depended upon the type of trigger (flow or pressure), type of circuit and patient profile. Differences were observed between the preset and measured airway pressure and between the tidal volume measured by the ventilator and on the bench. Leaks were associated with an inability to detect the patient's inspiratory effort or autotriggering. No single ventilator was able to adequately ventilate the six paediatric profiles. Only a few ventilators were able to ventilate the profiles simulating the youngest patients. A systematic paediatric bench evaluation is recommended for every ventilator proposed for home ventilation, in order to detect any dysfunction and guide the choice of the appropriate ventilator for a specific patient.

Measuring inspiratory muscle strength in neuromuscular disease: one test or two?

Inspiratory muscle strength monitoring is crucial in patients with neuromuscular disorders. The sniff nasal inspiratory pressure (SNIP) and maximal inspiratory pressure (P(I,max)) are usually measured. The present study investigated whether the test yielding the best value at baseline continued to yield the best value during follow-up. The present study included 25 patients with Duchenne muscular dystrophy (DMD) and 61 with myotonic muscular dystrophy (MMD). SNIP and P(I,max) were measured at baseline and then annually. At baseline, SNIP was lower than P(I,max) in 20 (80%) DMD patients and 32 (52%) MMD patients. During follow-up in DMD patients, changes in the best method always occurred from SNIP to P(I,max). In MMD patients, when SNIP was better than P(I,max) at baseline, SNIP was usually (88%) better during follow-up, whereas a better P(I,max) than SNIP at baseline was frequently (50%) followed by a shift to SNIP. Maximal inspiratory pressure may be sufficient for monitoring inspiratory muscle function in Duchenne muscular dystrophy adults. In myotonic muscular dystrophy, the marked variability in the test yielding the best value at baseline indicates a need for performance of both tests at baseline. However, when sniff nasal inspiratory pressure measurement yields the best value at baseline, using sniff nasal inspiratory pressure alone during follow-up may be appropriate.

[Domiciliary non-invasive ventilation in children]. / L'assistance ventilatoire non invasive a domicile chez l'enfant.

INTRODUCTION: Non-invasive positive pressure ventilation (NPPV) represents a particularly interesting technique of ventilatory support in paediatrics. Indeed, a significant number of pathologies that may be responsible for chronic respiratory insufficiency in childhood, such as neuromuscular diseases, obstruction of the upper airways, disorders of chest wall and/or the lungs, and disorders of ventilatory control may all lead to alveolar hypoventilation that can be improved by ventilatory support. BACKGROUND: Few physiological studies have been performed on NPPV in children. The most appropriate modes and settings for each pathology have not been clearly defined, and the criteria for commencing NPPV are based essentially on consensus guidelines for the management of neuromuscular disorders. VIEWPOINT: All the health care professionals managing these children should combine their efforts to evaluate more precisely the medium and long-term physiological effects of NPPV on the respiratory muscles, the development of the respiratory system, inspiratory activity, the indications for starting treatment and, above all, the benefits in terms of psycho-neurological development and quality of life. CONCLUSIONS: A better evaluation of the medium and long-term physiological and psychological benefits together with technical improvements in ventilators and associated equipment should allow a rapid expansion in the use of domiciliary NPPV in children.

Caspase-independent apoptosis in infected macrophages triggered by sulforaphane via Nrf2/p38 signaling pathways.

Mycobacterium abscessus (Mabs), a non-tuberculous mycobacterium, is an emerging and rapidly growing opportunistic pathogen that is frequently found in patients with cystic fibrosis and in immunosuppressed patients. Its high tolerance to antibiotics is of great concern for public health. In this study, our results showed that human THP-1-derived macrophages infected with M. abscessus presented an increase in ROS production and cell necrosis. In addition, M. abscessus infection triggered activation of the Nuclear factor E2-related factor 2 (Nrf2) signaling pathway, and the induction of HO-1 and NQO1 expression levels. Interestingly, pretreatment of macrophages with sulforaphane (SFN), an activator of the antioxidant key regulator Nrf2, followed by M. abscessus infection significantly decreased mycobacterial burden. We demonstrated that this reduction in mycobacterial growth was due to an activation in cell apoptosis in SFN-pretreated and M. abscessus-infected macrophages. Pretreatment with specific MAPK inhibitors, PD98059, SP600125, and SB203580 to ERK, JNK, and p38 respectively, failed to inhibit induction of Nrf2 expression, suggesting that Nrf2 signaling pathway was upstream of MAPK signaling. Activation of cell apoptosis was caspase 3/7 independent but p38 MAPK dependent. Moreover, p38 MAPK induction was abolished in macrophages transfected with Nrf2 siRNA. In addition, p38 inhibitor abolished Nrf2-dependent apoptosis in infected macrophages. Taken together, our results indicate that modulation of the Nrf2 signaling using Nrf2 activators may help potentiate the actual drug therapies used to treat mycobacterial infection.

MMP-9 correlates with electrophysiologic abnormalities in Guillain-Barré syndrome.

To investigate the role of MMP-9 in Guillain-Barré syndrome, the authors correlated electrophysiologic abnormalities and MMP-9 plasma levels in a series of 21 patients. MMP-9 plasma levels were higher in the demyelinating group than in the nondemyelinating group, and in patients with high CSF protein level. Increase of MMP-9 circulating levels correlated with the increase of F waves latencies, reduction of CMAP amplitude, and decrease of nerve conduction velocities. Circulating MMP-9 may contribute to the peripheral nerve dysfunction of demyelinating Guillain-Barré syndrome.

Utility of actigraphy in the diagnosis of obstructive sleep apnea.

STUDY OBJECTIVES: To determine whether adding actimetry to simplified polygraphy (respiratory-parameter monitoring without neurophysiologic variable recording) improves apnea-hypopnea index (AHI) evaluation as compared to simplified polygraphy alone. DESIGN: Comparison of AHI values obtained by all-night polysomnography and by simplified polygraphy with and without actimetry. SETTING: A teaching-hospital sleep laboratory in Garches, France. PATIENTS: 20 adults with suspected obstructive sleep apnea syndrome (OSAS). MEASUREMENTS AND RESULTS: Data were analyzed by two scorers working independently. AHI was calculated as the number of apneas and hypopneas per hour of sleep time (polysomnography: AHI-pg), per hour of time in bed (simplified polygraphy: AHI-tib), and per hour of actimetry-estimated total sleep time (AHI-act). AHI-pg showed that 12 patients had OSAS (AHI>10), which was severe (AHI > or =30) in eight. AHI-act was more closely correlated to AHI-pg (r=0.976) than was AHI-tib (r=0.940). According to the Bland and Altman method, AHI-tib underestimated the AHI in two patients and AHI-act overestimated the AHI in one patient. For the diagnosis of severe OSAS, sensitivity and negative predictive value were 50% and 75% with AHI-tib as compared to 88% and 92.5% with AHI-act. CONCLUSIONS: Actimetry, when added to simplified polygraphy, may assist in the diagnosis of OSAS.

Prevalence of sleep-disordered breathing in patients on a heart transplant waiting list.

We investigated the prevalence of sleep-disordered breathing in 20 outpatients on a heart transplant waiting list. All were younger than 60 years and had severe stable cardiac failure with a cardiac index below 2.5 L/min/m2 and a left ventricular ejection fraction below 25%. Nine patients (45%) exhibited ten or more apneas and hypopneas per hour of sleep (apneic group). In all patients but one, apneas and hypopneas were predominantly of the central type and occurred during Cheyne-Stokes respiration. There were no statistically significant differences between the apneic and nonapneic groups of patients in terms of age (51 +/- 5 years vs 49 +/- 11), body mass index (24 +/- 4 kg/m2 vs 22 +/- 3), cardiac index (1.87 +/- 0.35 L/min/m2 vs 1.84 +/- 0.40), isotopic left ventricular ejection fraction (13 +/- 5 vs 12 +/- 3%), arterial blood gas, or pulmonary function tests. Hypnogram characteristics showed poorer sleep quality in the apneic group than in the nonapneic group, with a larger number of arousals; this difference was found both for arousals lasting more than 30 s (8 +/- 5/h vs 4 +/- 2) and for arousals lasting less than 30 s (18 +/- 16/h vs 5 +/- 6) and was associated with increased wakefulness after sleep onset in the apneic group (138 +/- 82 min vs 84 +/- 45). Arousals were strongly associated with hyperpneic phases of Cheyne-Stokes respiration. We conclude that sleep-disordered breathing is common in patients with end-stage heart disease and adversely affects the quality of sleep.

Evaluation of carbon dioxide rebreathing during pressure support ventilation with airway management system (BiPAP) devices.

The purpose of this study was to evaluate whether carbon dioxide (CO2) rebreathing occurs in acute respiratory failure patients ventilated using the standard airway management system (BiPAP pressure support ventilator; Respironics; Murrysville, Pa) with positive inspiratory airway pressure and a minimal level of positive end-expiratory pressure (PEEP) and whether any CO2 rebreathing may be efficiently prevented by the addition of a nonrebreathing valve to the BiPAP system circuit. In the first part of the study, the standard device was tested on a lung model with a nonrebreathing valve (BiPAP-NRV) and with the usual Whisper Swivel connector (BiPAP-uc). With the BiPAP-uc device, the resident volume of expired air in the inspiratory circuit at the end of expiration (RVEA) was 55% of the tidal volume (VT) when the inspiratory pressure was 10 cm H2O and the frequency was at 15 cycles per minute. The BiPAP-NRV device efficiently prevented CO2 rebreathing but resulted in a slight decrease in VT, which was due to a significant increase in external PEEP (2.4 vs 1.3 cm H2O) caused by the additional expiratory valve resistance. For similar reasons, both the pressure swing necessary to trigger pressure support and the imposed expiratory work were increased in the lung model when the nonrebreathing valve was used. In the second part of the study, seven patients weaned from mechanical ventilation were investigated using a randomized crossover design to compare three situations: pressure support ventilation with a conventional intensive care ventilator (CIPS), BiPAP system use, and BiPAP-NRV. When we compared the BiPAP system use with the other two systems, we observed no significant effect on blood gases but found significant increases in VT, minute ventilation, and work of breathing. These findings are experimental and are clinical evidence that significant CO2 rebreathing occurs with the standard BiPAP system. This drawback can be overcome by using a non-rebreathing valve, but only at the expense of greater expiratory resistance.

Combined effects of a mechanical nasal dilator and a topical decongestant on nasal airflow resistance.

The goal of this study was to compare the isolated and combined effects of two treatments being used to reduce nasal airflow resistance (NR): an internal nasal mechanical dilator (Nozovent; Prevancure; Sté Pouret, Paris, France) and a topical decongestant, fenoxazoline hydrochloride (Aturgyl; Synthelabo; Le Plessis-Robinson, France). The study was performed in 17 healthy subjects. NR was estimated by active posterior rhinometry at a 0.5 L/s flow under four conditions: in the basal state, with the internal nasal mechanical dilator, after treatment with fenoxazoline hydrochloride, and with both fenoxazoline hydrochloride and the mechanical dilator. The mean NR (+/- SD) decreased from 1.65+/-0.54 cm H2O/L/s in the basal state to 1.02+/-0.27 cm H2O/L/s with the mechanical dilator (p < 0.001), 1.03+/-0.47 cm H2O/L/s with fenoxazoline hydrochloride (p < 0.001), and 0.48+/-0.15 cm H2O/L/s with both the mechanical dilator and fenoxazoline hydrochloride (p < 0.001). The decreases in NR observed after using either the mechanical dilator (deltaNR(N)) or fenoxazoline hydrochloride (deltaNR(A)) were not significantly different. The decrease in NR observed with both (deltaNR(N + A)) was not significantly different from the sum deltaNR(N) + deltaNR(A): 1.16+/-0.53 cm H2O/L/s vs 1.25+/-0.63 cm H2O/L/s, respectively (p > 0.05). deltaNR(N + A) strongly correlated with deltaNR(N) + deltaNR(A): deltaNR(N + A) = 0.80 (deltaNR(N) + deltaNR(A)) + 0.15 (r = 0.96; p < 0.0001). However, the slope of the regression line of deltaNR(N + A) vs deltaNR(N) + deltaNR(A) was significantly lower than unity (p < 0.003). These results demonstrate that, although not totally additive, the effects of using the mechanical dilator and fenoxazoline hydrochloride are cumulative. Further studies that include patients with nasal obstruction would allow us to better evaluate the benefit of a therapy combining both treatments.

Arterial blood pressure response to transient arousals from NREM sleep in nonapneic snorers with sleep fragmentation.

STUDY OBJECTIVES: To assess the hemodynamic effects of graded arousals during nonrapid eye movement (NREM) sleep in patients with partial upper airway obstruction during sleep without obstructive sleep apnea/hypopnea, overnight beat-to-beat BP was recorded in six patients. SETTING: At the end of each nonapneic obstructive event, EEG responses were graded as follows: grade 2, grade 1, and grade 0 were defined as increased high-frequency EEG lasting >15 s, 3 to 15 s, and no EEG arousals according to the American Sleep Disorders Association, respectively. MEASUREMENTS AND RESULTS: The following were observed during grade 0, 1, and 2 EEG patterns (mean+/-SD): systolic pressure increased by 7.1+/-1.5, 11.7+/-1.9, and 14.2+/-3.4 (p<0.005), respectively; diastolic pressure increased by 4.6+/-0.6, 6.7+/-1.7, and 9.4+/-3.0 (p<0.005), respectively; heart rate increased by 2.9+/-0.4, 3.9+/-2.2, and 8.6+/-4.6 (p<0.005), respectively. CONCLUSIONS: We conclude that nonapneic-nonhypopneic obstructive events are followed by arterial systemic pressure increases whose magnitude varies with the grade of the arousal.