SEARCH · PubMed Health

Results for “Supine Position”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources

PubMed1993

The role of intraabdominal pressure in venous blood drainage from the prostate into the vertebral vein system.

We investigated venous blood drainage from the prostate into the vertebral vein system by cineangiography in five mongrel dogs and measured intraabdominal pressure and venous blood pressure in the dog or human to study the role of intraabdominal pressure in the drainage. The averages of intraabdominal pressure and caudal vena caval pressure in the dog were 32.2 +/- 3.0 and 12.8 +/- 1.3 mmHg, respectively, in the supine position, and 39.2 +/- 3.0 and 23.8 +/- 4.0 mmHg, respectively, in the head-up tilt position, when the radiopaque medium injected into the dorsal penile vein appeared in the vertebral vein system. Intraabdominal pressure in the head-up tilt position was significantly higher than that in the supine position when the venous drainage into the vertebral veins happened. In eight continuous ambulatory peritoneal dialysis patients, intraabdominal pressure showed 8.1 +/- 2.4 mmHg in the supine position, 24.6 +/- 4.3 mmHg in the sitting position, and 30.4 +/- 4.9 mmHg in the standing position at rest. During voluntary contraction of the abdominal muscles, the pressure was increased up to 50.6 +/- 21.6 mmHg in the supine position, 69.3 +/- 19.8 mmHg in the sitting position, and 73.8 +/- 19.8 mmHg in the standing position. These pressure values in the human were significantly higher than those observed at the time when the radiopaque medium appeared in the vertebral veins in both supine and head-up tilt positions in the canine. These results suggest that the increase of intraabdominal pressure causes inflow of prostatic venous blood into the vertebral veins via the inferior vena cava, common iliac vein, or internal iliac vein.

Abdomen↗

PubMed2005

Effect of laser-assisted uvulopalatoplasty on oral airway resistance during wakefulness in obstructive sleep apnea syndrome.

The aim of the study was to evaluate the effects of successful laser-assisted uvulopalatoplasty (LAUP) on oral airway resistance (R(OA)) during wakefulness in patients with OSAS. Fifteen healthy subjects (group I) and 25 subjects (group II) with moderately severe or severe obstructive sleep apnea syndrome (OSAS) proven by an overnight sleep study and who desired LAUP were enrolled. All underwent an overnight sleep study, pulmonary function testing and measurement of oral airway resistance [R(OA) (including impedance (Zrs), resistance (R) and reactance (X)] measurement by Impulse Oscillometry (IOS) (MasterScreen IOS, VIASYS Healthcare GmbH, Germany) in the upright (seated) position and then in the supine position while awake. Group II subjects had these measurements twice, both before and 3 months after LAUP. Based on the assessment of their sleep study after LAUP, they were divided into two groups: responders (group IIa) and nonresponders (group IIb). Zrs was normal in the sitting position both before and after LAUP in both groups IIa and IIb and comparable to that of group I controls. There was an increase in Zrs in the supine position in both groups IIa and IIb subjects before LAUP. After LAUP, the Zrs in group IIb subjects remained elevated, while that in group IIa subjects returned to levels comparable to those in the normal controls. OSAS patients before LAUP have abnormal R(OA) in the supine position as reflected by a high Zrs. The Zrs is improved after LAUP that successfully ameliorates OSAS.

Adult↗

PubMed2005

Effect of acute body positional changes on the haemodynamics of rats with and without myocardial infarction.

In humans, the lateral recumbent position has a beneficial effect on haemodynamics. If this effect is substantial in small animals too, there is a risk of misinterpretation in preclinical investigations. Therefore, the aim of this study was to analyse the impact of acute changes in body position on haemodynamics in rats. Healthy rats (n=21) and rats post myocardial infarction (n=20) were randomly positioned supine, prone, or on the right or left side. In each position, we measured haemodynamic parameters by pressure-tip catheter and thermodilution. We found that left ventricular contractility (dP/dtmax) was significantly elevated in both lateral positions as compared to the supine position in healthy rats. In healthy rats and following infarction, cardiac index (CI) and stroke volume index (SVI) were significantly higher in both lateral positions as compared to the supine or prone position. Of importance, if SVI values in the supine position in healthy rats (0.095 +/- 0.003 ml (100 g)(-1)) are compared to SVI values measured in different positions after myocardial infarction, the SVI can be either significantly lower in the supine (0.084 +/- 0.003 ml (100 g)(-1)) or significantly higher in the left lateral position (0.105 +/- 0.003 ml (100 g)(-1)). We conclude that post myocardial infarction and in healthy control rats, important haemodynamic values are increased in lateral positions as compared to prone or supine positions. Analysing haemodynamic data in rats may therefore result in misinterpretation if the body position is inconsistent.

Algorithms↗

PubMed1998

Autonomic modulation of the atrial cycle length by the head up tilt test: non-invasive evaluation in patients with chronic atrial fibrillation.

OBJECTIVE: To determine the effects of upright posture compared with supine position on the dominant atrial cycle length (DACL) in patients with chronic atrial fibrillation. DESIGN: The power/frequency spectrum of QRST suppressed lead V1 ECG was studied in 14 patients in the supine position and during the head up tilt table test. The DACL changes were compared with changes in heart rate and blood pressure. RESULTS: Compared with the supine position, the upright position reduced the DACL from 160 to 150 ms (p < 0.01). The DACL was increased after returning to the supine position from the upright position, from 147 to 154 ms (p < 0.01). Heart rate increased from 91 beats/min in the supine position to 106 in the upright position (p < 0.01). There was a decrease in heart rate from 109 beats/min in the upright position to 93 after returning to the supine position (p < 0.01). No significant changes were seen in systolic or diastolic blood pressure. There were indications of an inverse relation between DACL and heart rate when comparing the supine position before and after tilt with the upright position (p < 0.001). CONCLUSIONS: The sympathetic stimulation and vagal withdrawal induced by rising to upright body position are associated with a decrease in DACL during chronic atrial fibrillation. Thus a reflex increase in sympathetic discharge after induction of atrial fibrillation could favour the persistence of the arrhythmia.

Aged↗

PubMed2005

Supine MR mammography using VIBE with parallel acquisition technique for the planning of breast-conserving surgery: clinical feasibility.

Volumetric interpolated breath-hold examination (VIBE), which provides both high-spatial and high-temporal resolution images, is a useful sequence for determining the extent of breast cancer. The VIBE sequence in combination with the parallel acquisition technique allows for a single breath-hold evaluation of the breast. We evaluated the clinical feasibility of MR mammography in the supine oblique position (supine MRM) using this technique for planning breast conservation surgery. The accuracy of determination of the tumor extent with a deviation of less than 2 cm in length was 90% (36/40). Two cases showed a positive surgical margin (7.4%). Supine MRM is feasible for the planning of breast-conserving surgery.

Adult↗

PubMed1993

Effects of posture on carbon dioxide responsiveness in patients with obstructive sleep apnoea.

BACKGROUND: It is well known that upper airway resistance increases with postural change from a sitting to supine position in patients with obstructive sleep apnoea (OSA). It is not known, however, how the postural change affects the ventilatory and occlusion pressure response to hypercapnia in patients with OSA when awake. METHODS: The responses of minute ventilation (VE) and mouth pressure 0.1 seconds after the onset of occluded inspiration (P0.1) to progressive hypercapnia (delta VE/delta PCO2, delta P0.1/delta PCO2) both in sitting and supine positions were measured in 20 patients with OSA. The ratio of the two (delta VE/delta P0.1) was obtained as an index of breathing efficiency. The postural changes in response to carbon dioxide (CO2) after uvulopalatopharyngoplasty (UPPP) were also compared in seven patients with OSA. RESULTS: There were no significant changes in the resting values of end tidal PCO2, P0.1, or VE between the two positions. During CO2 rebreathing, delta VE/delta PCO2 did not differ between the two positions, but delta P0.1/delta PCO2 was significantly higher in the supine than in the sitting position (supine, mean 0.67 (SE 0.09) cm H2O/mm Hg; sitting, mean 0.57 (SE 0.08) cm H2O/mm Hg), and delta VE/delta P0.1 decreased significantly from the sitting to the supine position (sitting, 4.6 (0.4) l/min/cm H2O; supine, 3.9 (0.4) l/min/cm H2O). In seven patients with OSA who underwent UPPP, delta VE/delta P0.1 improved significantly in the supine position and postural change in delta VE/delta P0.1 was eliminated. CONCLUSIONS: These results suggest that in patients with OSA the inspiratory drive in the supine position increases to maintain the same level of ventilation as in the sitting position, and that the postural change from sitting to supine reduces breathing efficiency. Load compensation mechanisms of patients with OSA appear to be intact while awake in response to the rise in upper airway resistance.

Female↗

PubMed1994

Effects of beta-adrenergic blockade on vasodepressor reaction in patients with vasodepressor syncope.

The mechanism of vasodepressor reaction induced by head-up tilt test in patients with vasodepressor syncope is not clearly understood. We hypothesized that an abnormal alteration of beta-adrenergic transmission could be involved in these patients. We measured plasma catecholamine concentration during tilt and density of beta-adrenoceptors and tested the effects of beta-adrenergic blockers in the prevention of the vasodepressor reaction in patients with vasodepressor syncope. Ten patients had reproducibly induced vasodepressor syncope (mean 3.1 +/- 0.3 episodes in each patient) with head-up tilt (80 degrees) for 10 minutes with isoproterenol infusion (1 to 3 micrograms/min). Syncope occurred at 6.3 +/- 1.7 minutes during tilt with isoproterenol infusion. The plasma norepinephrine concentration before administration of beta-blocker was significantly elevated during tilt compared to the supine position (0.347 +/- 0.079 ng/ml in supine position with isoproterenol vs 0.468 +/- 0.082 ng/ml at 3 minutes of tilt, p < 0.001, and vs 0.503 +/- 0.106 ng/ml at the onset of vasodepressor reaction, p < 0.005; n = 8). Plasma norepinephrine after administration of the selective beta 1-adrenergic blocker metoprolol (40 mg/day) was similarly elevated (0.282 +/- 0.071 ng/ml in supine position with isoproterenol vs 0.390 +/- 0.078 ng/ml at 3 minutes of tilt, p < 0.05, n = 6; and vs 0.547 +/- 0.152 ng/ml at the onset of vasodepressor reaction, p < 0.001, n = 3).(ABSTRACT TRUNCATED AT 250 WORDS)

Epinephrine↗

PubMed1989

Effects of posture on the venodilatory response to nitroglycerin.

To determine the effects of posture on the venodilatory response to nitroglycerin (TNG), the change in forearm venous volume after inflation of an upper arm cuff to 30 mmHg above cuff zero (VV[30]) was measured during control conditions and after TNG (0.8 mg spray) in 18 healthy young volunteers in the supine position and the sitting position. VV[30] was 3.24 +/- 0.98 ml/100 ml arm in the supine position and 2.46 +/- 1.32 ml/100 ml arm in the sitting position. TNG increased VV[30] by 0.56 +/- 0.19 ml/100 ml arm in supine subjects, but by only 0.38 +/- 0.17 ml/100 ml arm in sitting subjects (P = 0.013). When limb volume was measured in the forearm and calf without using a cuff to produce venous congestion, the increase in limb volume with TNG was significantly greater in the sitting than in the supine position. Because the fall in both systolic and diastolic pressure and the rise in heart rate were significantly greater after TNG was administered in the sitting position, it is suggested that a greater reflex venoconstriction occurred in this posture, which antagonized the TNG-induced increase in venous distensibility. In the seated position, the effect of gravity more than compensated for the impaired venodilatory response to TNG. These results suggest that TNG causes a greater reduction in venous return to the heart when administered in the sitting position than in the supine position.

Adult↗

PubMed1998

Effects of Sl nerve-root lengthening on tibial nerve F-wave latency in healthy subjects.

OBJECTIVE: To determine if lengthening the tibial portion of the sciatic nerve in healthy patients significantly alters F-wave latency. SUBJECTS: Ten volunteer students (6 men and 4 women). SETTING: Chiropractic college clinic. METHODS: F-wave latency was measured bilaterally in the supine position and supine in 40-50 degrees of passive hip flexion. Block randomization determined the test sequence. Supramaximal surface stimulation was delivered over the tibial nerve using transcutaneous electrical stimulation. The nerve was stimulated no more than 30 times at a rate of 1 Hz for 0.5 ms to get 16 F-wave latencies. The paired t test was used to determine mean difference between neutral and flexion. RESULTS: The F-wave latency was found to be longer in hip flexion (average 46.12 +/- 3.80 ms) than neutral (average 45.12 +/- 3.33 ms). CONCLUSION: Positioning a patient to optimize nerve lengthening and elicit symptoms may reveal occult dysfunction in electrodiagnostic examination.

Adult↗

PubMedDate not supplied

[Kinetic therapy for acute respiratory distress syndrome].

The authors evaluated the clinical and physiological effects of kinetic therapy (KT) in the treatment of acute respiratory distress syndrome (ARDS). Forty-six patients with ARDS underwent successive postural positioning in accordance with two regimens: 1) lateral, prone, contralateral, supine positions; 2) prone, lateral, contralateral, supine positions. The criterion for changing each position was the change in monitoring indices: SpO2, PaO2, and thoracopulmonary compliance (C). KT was performed until a respirator was withdrawn from the patient. In 25 patients, each maneuver of positioning was made during 30-minute propofol sedation. The control group included 24 patients with ARDS who received neither KT nor propofol sedation. KT caused a decrease in Vd/Vt, Qs/Qt and an increase in PaO2/FiO2 and C was more intensive, as compared with the control group. The duration of the patient's prone position was 3.2-0.7 hours and that of the supine position was 3.4-0.8 hours. The right and left lateral positions lasted 1.1-0.2 and 1.3-0.2 hours, respectively. KT regimen 1 was found to be more effective than KT regimen 2. Propofol sedation enhanced the efficiency of KT. The latter reduced death rates in patients with ARDS.

Adult↗

PubMed2001

The importance of nasal resistance in obstructive sleep apnea syndrome: a study with positional rhinomanometry.

The importance of nasal obstruction in the pathogenesis of obstructive sleep apnea syndrome (OSAS) has not yet been totally defined. Numerous studies have reported an association between nasal obstruction and OSAS, but the precise nature of this relationship remains to be clarified. This study was undertaken to evaluate the prevalence of nasal obstruction disorders in a group of OSAS patients. For this purpose, we analyzed the nasal resistance of 36 OSAS patients by performing a traditional basal anterior active rhinomanometry test (AAR) and a positional AAR, with the patient in a supine position. Seven patients had a pathologic nasal resistance in the seated position that increased further in the supine position; 9 patients had normal resistance in the seated position but a pathologic resistance in the supine position. In 20 patients, nasal resistance was normal in both positions. No statistically significant differences in the degree of apnea/hypopnea index (AHI) was found between the 20 patients with normal positional AAR and the 16 with pathologic positional AAR (p = 0.13). Moreover, no statistically significant differences in the degree of AHI was found between the 7 patients with pathologic basal and positional AAR and the 9 patients with normal basal AAR and pathologic positional AAR (p = 0.38).

Adult↗

PubMed2006

Intraoperative pedography: a validated method for static intraoperative biomechanical assessment.

BACKGROUND: A new device was developed to perform intraoperative static pedography. The purpose of this study was to validate the introduced method by a comparison with the standard method for dynamic and static pedography. METHODS: A device known as Kraftsimulator Intraoperative Pedographie (KIOP) was developed for intraoperative placement of standardized forces to the sole of the foot. Pedographic measurements were done with a custom-made mat that was inserted into the KIOP (Pliance, Novel Inc., St. Paul, MN, USA). Validation was done in two steps: (1) comparison of standard dynamic pedography walking on a platform, standard static pedography in standing on a platform, and pedography with KIOP in supine position in 30 healthy volunteers, and (2) comparison of static pedography in standing position, pedography with KIOP supine awake, and pedography with KIOP supine with 30 patients under anesthesia. Individuals who had operative procedures at the knee or distal to the knee were excluded. The different measurements were compared (one-way ANOVA, t-test; significance level 0.05). RESULTS: No significant differences were found among all measurements for the hindfoot compared to midfoot-forefoot force distribution. For the medial compared to lateral force distribution and the 10-region-mapping, significant differences were found when comparing all measurements (steps 1 and 2) and when comparing the measurements of step 1 only. No differences were found for these distributions when comparing the measurements of step 2 alone or when comparing the measurements of step 1 and 2 without the platform measurements of step 1 (dynamic walking pedography and static standing pedography). No significant differences in the force distributions were found in step 2 when comparing subjects without anesthesia, with general anesthesia, and with spinal anesthesia. CONCLUSIONS: The KIOP device allows a valid static intraoperative pedography measurement. No statistically significant force distribution differences were found between standing subjects and anesthetized subjects in the supine position.

Adult↗

PubMed2000

Effect of the 30 degree lateral recumbent position on pulmonary artery and pulmonary artery wedge pressures in critically ill adult cardiac surgery patients.

BACKGROUND: Despite demonstrated benefits of lateral positioning, critically ill patients may require prolonged supine positioning to obtain reproducible hemodynamic measurements. OBJECTIVES: TO determine the effect of 30 degree right and left lateral positions on pulmonary artery and pulmonary artery wedge pressures after cardiac surgery in critically ill adult patients. METHODS: An experimental repeated-measures design was used to study 35 patients with stable hemodynamics after cardiac surgery. Subjects were randomly assigned to 1 of 2 position sequences. Pulmonary artery and pulmonary artery wedge pressures were measured in each position. RESULTS: Measurements obtained from patients in the 30 degree left lateral position differed significantly (all Ps < .05) from measurements obtained from patients in the supine position for pulmonary artery systolic, end-diastolic, and mean pressures. Pulmonary artery wedge pressures did not differ significantly; however, data were available from only 17 subjects. The largest mean difference in pressures between the 2 positions was 2.0 +/- 2.1 mm Hg for pulmonary artery systolic pressures, whereas maximum differences for end-diastolic and pulmonary artery wedge pressures were 1.4 +/- 2.7 mm Hg and 1.6 +/- 2.4 mm Hg, respectively. Clinically significant position-related changes in pressure occurred in 12 (2.1%) of 581 pressure pairs. Clinically significant changes occurred in end-diastolic pressure in 2 subjects and in pulmonary artery wedge pressure in 1 subject. CONCLUSIONS: In patients with stable hemodynamics during the first 12 to 24 hours after cardiac surgery, measurements of pulmonary artery and pulmonary artery wedge pressures obtained in the 30 degree lateral and supine positions are clinically interchangeable.

Adult↗

PubMed2006

Orthopnea and tidal expiratory flow limitation in chronic heart failure.

BACKGROUND: Tidal expiratory flow limitation (FL) is common in patients with acute left heart failure and contributes significantly to orthopnea. Whether tidal FL exists in patients with chronic heart failure (CHF) remains to be determined. PURPOSES: To measure tidal FL and respiratory function in CHF patients and their relationships to orthopnea. METHODS: In 20 CHF patients (mean [+/- SD] ejection fraction, 23 +/- 8%; mean systolic pulmonary artery pressure [sPAP], 46 +/- 18 mm Hg; mean age, 59 +/- 11 years) and 20 control subjects who were matched for age and gender, we assessed FL, Borg score, spirometry, maximal inspiratory pressure (Pimax), mouth occlusion pressure 100 ms after the onset of inspiratory effort (P(0.1)), and breathing pattern in both the sitting and supine positions. The Medical Research Council score and orthopnea score were also determined. RESULTS: In the sitting position, tidal FL was absent in all patients and healthy subjects. In CHF patients, Pimax was reduced, and ventilation and P(0.1)/Pimax ratio was increased relative to those of control subjects. In the supine position, 12 CHF patients had FL and 18 CHF patients claimed orthopnea with a mean Borg score increasing from 0.5 +/- 0.7 in the sitting position to 2.7 +/- 1.5 in the supine position in CHF patients. In contrast, orthopnea was absent in all control subjects. The FL patients were older than the non-FL patients (mean age, 63 +/- 8 vs 53 +/- 12 years, respectively; p < 0.03). In shifting from the seated to the supine position, the P(0.1)/Pimax ratio and the effective inspiratory impedance increased more in CHF patients than in control subjects. The best predictors of orthopnea in CHF patients were sPAP, supine Pimax, and the percentage change in inspiratory capacity (IC) from the seated to the supine position (r(2) = 0.64; p < 0.001). CONCLUSIONS: In sitting CHF patients, tidal FL is absent but is common supine. Supine FL, together with increased respiratory impedance and decreased inspiratory muscle force, can elicit orthopnea, whom independent indicators are sPAP, supine Pimax and change in IC percentage.

Disease Progression↗

PubMedDate not supplied

Sleeping position and sleep apnea syndrome.

Four patients who were evaluated for hypersomnia-sleep apnea syndrome were found in all-night sleep studies to have obstructive or mixed apneas related to their sleeping positions. All four were available for comprehensive follow-up and were subsequently restudied while avoiding the supine position. Supine, prone, and lateral decubitus apnea indices were calculated for each patient for each night. The supine sleeping position was associated with significantly more apneas than the non-supine positions. Keeping these patients off their backs when they slept was effective treatment. Additionally, when results of surgical or pharmacologic treatments of apnea are evaluated, positional apnea indices should be considered.

Follow-Up Studies↗

PubMed1989

The effect of pH-adjusted 2-chloroprocaine on the onset of epidural analgesia in pregnant patients in the lying and sitting position during the first stage of labor.

The purpose of this prospective, randomized, double-blind study was to compare the epidural onset time of 2% 2-chloroprocaine with pH-adjusted 2-chloroprocaine administered in either the sitting or supine position in pregnant patients during the first stage of labor. Patients in Groups I and III received the control solution in the sitting and supine position, respectively. Patients in Groups II and IV received the buffered solution in the sitting and supine position, respectively. The pH and pCO2 of the control and buffered solutions differed significantly. The pH and pCO2 of the control and buffered solutions were 4.38 +/- 0.01, 18.4 +/- 2.2 mm Hg and 7.70 +/- 0.04, 114.9 +/- 3.0 mmHg, respectively. A statistically significant reduction in the time of onset of analgesia in the pH-adjusted groups was noted. Groups I and II had onset times of 4 +/- 1.2 and 4.3 +/- 1.0, whereas Groups II and IV had onset times of 2.6 +/- 0.9 and 2.7 +/- 0.6 min., respectively. There were no intergroup differences in the cephalad spread of analgesia or duration of analgesia. Position had no effect on the onset of analgesia at the S2-3 dermatomes nor on the bilateral cephalad spread of the epidural study solutions. Our results indicate that a pregnant patient may be dosed in the lateral supine position without adversely affecting the caudad or cephalad spread of plain or pH-adjusted 2% 2-chloroprocaine, which is clinically important because the incidence of aortocaval compression is increased in the supine position when compared with the lateral supine position.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1985

An electromyographic study of the immediate effect of an occlusal splint on the postural activity of the anterior temporal and masseter muscles in different body positions with and without visual input.

With the mandible at rest, the clinical postural position was measured and electromyographic recordings (in seated and supine position, eyes open and eyes closed, before as well as 15 min after insertion of an occlusal splint) were from the anterior temporal and masseter muscles in thirty-one patients with signs and symptoms of mandibular dysfunction and nocturnal bruxism. The results indicated that when the patients were seated upright, there was a distinct postural activity in the anterior temporal and in some patients also in the masseter muscles. This postural activity decreased significantly with closure of the eyes and in supine position. Fifteen minutes after insertion of an occlusal splint, the postural activity in the temporal muscles decreased in 52%, increased in 22% and remained unchanged in 26% of the patients. Moreover, the postural activity reached its lowest level in supine position. The results indicate that the supine position is the body position to be preferred for centric relation recording as well as for occlusal and splint adjustment.

Adolescent↗

PubMed2001

Prone positioning and inhaled nitric oxide: synergistic therapies for acute respiratory distress syndrome.

BACKGROUND: Inhaled nitric oxide (INO) and prone positioning have both been advocated as methods to improve oxygenation in patients with acute respiratory distress syndrome (ARDS). This study was designed to evaluate the relative contributions of INO and prone positioning alone and in combination on gas exchange in trauma patients with ARDS. METHODS: Sixteen patients meeting the consensus definition of ARDS were studied. Patients received mechanical ventilation in the supine position, mechanical ventilation plus INO at 1 part per million in the supine position, mechanical ventilation in the PP, and mechanical ventilation in the prone positioning plus INO at 1 part per million. A stabilization period of 1 hour was allowed at each condition. After stabilization,hemodynamic and gas exchange variables were measured. RESULTS: INO and prone positioning both increased PaO2/FIO2 compared with ventilation in the supine position. PaO2/FIO2 increased by 14% during use of INO, and 10 of 16 patients (62%) responded to INO in the supine position. PaO2/FIO2 increased by 33%, and 14 of 16 patients (87.5%) responded to the prone position. The combination of INO and prone positioning resulted in an improvement in PaO2/FIO2 in 15 of 16 patients(94%), with a mean increase in PaO2/FIO2 of 59%. Pulmonary vascular resistance was reduced during use of INO, with a greater reduction in pulmonary vascular resistance seen with INO plus prone positioning (175 +/- 36 dynes x s/cm5 vs. 134 +/- 28 dynes x s/cm5) compared with INO in the supine position (164 +/- 48 dynes x s/cm5 vs.138 +/- 44 dynes x s/cm5). There were no significant hemodynamic effects of INO or prone positioning and no complications were seen during this relative short duration of study. CONCLUSIONS: INO and prone positioning can contribute to improved oxygenation in patients with ARDS. The two therapies in combination are synergistic and may be important adjuncts to mechanical ventilation in the ARDS patient with refractory hypoxemia.

Administration, Inhalation↗