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At least 163 records · Page 9Linked to original sources
PubMed2003

Decrease in PaCO2 with prone position is predictive of improved outcome in acute respiratory distress syndrome.

OBJECTIVE: To determine whether gas exchange improvement in response to the prone position is associated with an improved outcome in acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). DESIGN: Retrospective analysis of patients in the pronation arm of a controlled randomized trial on prone positioning and patients enrolled in a previous pilot study of the prone position. SETTING: Twenty-eight Italian and two Swiss intensive care units. PATIENTS: We studied 225 patients meeting the criteria for ALI or ARDS. INTERVENTIONS: Patients were in prone position for 10 days for 6 hrs/day if they met ALI/ARDS criteria when assessed each morning. Respiratory variables were recorded before and after 6 hrs of pronation with unchanged ventilatory settings. MEASUREMENTS AND MAIN RESULTS: We measured arterial blood gas alterations to the first pronation and the 28-day mortality rate. The independent risk factors for death in the general population were the Pao2/Fio2 ratio (odds ratio, 0.992; confidence interval, 0.986-0.998), the minute ventilation/Paco2 ratio (odds ratio, 1.003; confidence interval, 1.000-1.006), and the concentration of plasma creatinine (odds ratio, 1.385; confidence interval, 1.116-1.720). Pao2 responders (defined as the patients who increased their Pao2/Fio2 by > or =20 mm Hg, 150 patients, mean increase of 100.6 +/- 61.6 mm Hg [13.4 +/- 8.2 kPa]) had an outcome similar to the nonresponders (59 patients, mean decrease -6.3 +/- 23.7 mm Hg [-0.8 +/- 3.2 kPa]; mortality rate 44% and 46%, respectively; relative risk, 1.04; confidence interval, 0.74-1.45, p =.65). The Paco2 responders (defined as patients whose Paco2 decreased by > or =1 mm Hg, 94 patients, mean decrease -6.0 +/- 6 mm Hg [-0.8 +/- 0.8 kPa]) had an improved survival when compared with nonresponders (115 patients, mean increase 6 +/- 6 mm Hg [0.8 +/- 0.8 kPa]; mortality rate 35.1% and 52.2%, respectively; relative risk, 1.48; confidence interval, 1.07-2.05, p =.01). CONCLUSION: ALI/ARDS patients who respond to prone positioning with reduction of their Paco2 show an increased survival at 28 days. Improved efficiency of alveolar ventilation (decreased physiologic deadspace ratio) is an important marker of patients who will survive acute respiratory failure.

Aged↗
PubMed1994

Prone position breast irradiation.

PURPOSE: An alternative technique for irradiating the breast following breast conserving surgery is described. METHODS AND MATERIALS: The technique utilizes the prone position and has been developed to improve the dose distribution within the breast and reduce the volume of normal tissues irradiated during whole breast treatment. Improvements in the dosimetry of breast irradiation are obtained through the optimization of the shape of the breast and result in a reduction in the magnitude of high-dose regions and isodose gradients at the base of the breast. RESULTS: The high dose region at the base of the breast, without lung correction, generally ranges from 116-118% for large breasted women treated in the supine position. These high dose regions are reduced to 102-103% for the same women treated in the prone position. Irradiation of the heart, lungs, chest wall and contralateral breast are minimized with this technique. The improvements appear to benefit women with large breasts, pendulous breasts, large separations and/or irregularly shaped chest contours. CONCLUSION: The prone position technique takes advantage of the reproducibility characteristics of the supine position technique and combines them with the homogeneity and normal tissue-sparing characteristics of the lateral decubitus position technique. Prone position breast irradiation appears to be a simple and effective alternative to irradiation of the breast in the conventional supine position when the supine position is likely to result in unacceptable dose inhomogeneity or significant doses to normal tissues.

Breast↗
PubMed2006

Clinical trial design--effect of prone positioning on clinical outcomes in infants and children with acute respiratory distress syndrome.

PURPOSE: This paper describes the methodology of a clinical trial of prone positioning in pediatric patients with acute lung injury (ALI). Nonrandomized studies suggest that prone positioning improves oxygenation in patients with ALI/acute respiratory distress syndrome without the risk of serious iatrogenic injury. It is not known if these improvements in oxygenation result in improvements in clinical outcomes. A clinical trial was needed to answer this question. MATERIALS AND METHODS: The pediatric prone study is a multicenter, randomized, noncrossover, controlled clinical trial. The trial is designed to test the hypothesis that at the end of 28 days, children with ALI treated with prone positioning will have more ventilator-free days than children treated with supine positioning. Secondary end points include the time to recovery of lung injury, organ failure-free days, functional outcome, adverse events, and mortality from all causes. Pediatric patients, 42 weeks postconceptual age to 18 years of age, are enrolled within 48 hours of meeting ALI criteria. Patients randomized to the prone group are positioned prone within 4 hours of randomization and remain prone for 20 hours each day during the acute phase of their illness for a maximum of 7 days. Both groups are managed according to ventilator protocol, extubation readiness testing, and sedation protocols and hemodynamic, nutrition, and skin care guidelines. CONCLUSIONS: This paper describes the process, multidisciplinary input, and procedures used to support the design of the clinical trial, as well as the challenges faced by the clinical scientists during the conduct of the clinical trial.

Adolescent↗
PubMed2003

Unusual presentation and complication of the prone position for spinal surgery.

Patient positioning for operative procedures has long been associated with perioperative complications. We present a case report of shoulder dislocation, which occurred following positioning in the prone position, and was detected by axillary artery occlusion resulting in the loss of the radial artery blood pressure line waveform. We discuss the diagnosis and consequences of this complication.

Acetabulum↗
PubMed2003

Prone position in subarachnoid hemorrhage patients with acute respiratory distress syndrome: effects on cerebral tissue oxygenation and intracranial pressure.

OBJECTIVE: To analyze the effect of prone position on cerebral perfusion pressure and brain tissue oxygen partial pressure in subarachnoid hemorrhage patients with acute respiratory distress syndrome (ARDS). DESIGN: Clinical study with retrospective data analysis. SETTING: Neurosurgical intensive care unit of a primary level university hospital. PATIENTS: Sixteen patients treated for intracranial aneurysm rupture with initial Hunt and Hess grade III or worse who developed ARDS within 2 wks after the bleeding. INTERVENTIONS: Routine neurosurgical intensive care treatment for subarachnoid hemorrhage and posthemorrhagic vasospasm including cerebral monitoring with continuous intracranial pressure and brain tissue oxygen partial pressure recordings. MEASUREMENTS AND MAIN RESULTS: Hemodynamics, arterial oxygenation, ventilatory setting, intracranial pressure, cerebral perfusion pressure, and brain tissue oxygen partial pressure in the supine as well as in the prone position were analyzed and compared. A significant increase in Pao(2) from 97.3 +/- 20.7 torr (mean +/- sd) in the supine position to 126.6 +/- 31.7 torr in the prone position was joined by a significant increase in brain tissue oxygen partial pressure from 26.8 +/- 10.9 torr to 31.6 +/- 12.2 torr (both p <.0001), whereas intracranial pressure increased from 9.3 +/- 5.2 mm Hg to 14.8 +/- 6.7 mm Hg and cerebral perfusion pressure decreased from 73.0 +/- 10.5 mm Hg to 67.7 +/- 10.7 mm Hg (both p <.0001). CONCLUSIONS: The beneficial effect of prone positioning on cerebral tissue oxygenation by increasing arterial oxygenation appears to outweigh the expected adverse effect of prone positioning on cerebral tissue oxygenation by decreasing cerebral perfusion pressure in ARDS patients.

Adult↗
PubMed2000

[Ventilation in prone position in a 5-year-old child after multiple trauma. Effective treatment of persistent atelectasis].

We report on the ventilation in prone position in a 5-year-old traumatized child with severe thoracic and abdominal injuries (lung contusion, rib fractures, rupture of liver and spleen). Under continuous analgesic sedation, the young patient was ventilated in prone position for 6 h, since acute lung injury and atelectasis persisted despite various therapeutic measures (artificial ventilation in the pressure controlled mode, fiberoptic bronchoscopy, reexpansion maneuver). After initiation of the prone position, we observed a rapid increase in arterial oxygenation, which persisted in the following period. The hemodynamic situation remained stable. The complete disappearance of atelectasis was demonstrated radiologically after supine repositioning. After cessation of analgesic sedation, the extubation was performed 2 days later. Furthermore, we found no side effects of the prone position on the injured abdomen, and the liver function improved rapidly. Although there is a lack of experience with ventilation in prone position in pediatric intensive care, our report might be a recommendation for the indication of this technique in children.

Abdominal Injuries↗
PubMed2004

Effects of systematic prone positioning in hypoxemic acute respiratory failure: a randomized controlled trial.

CONTEXT: A recent trial showed that placing patients with acute lung injury in the prone position did not increase survival; however, whether those results hold true for patients with hypoxemic acute respiratory failure (ARF) is unclear. OBJECTIVE: To determine whether prone positioning improves mortality in ARF patients. DESIGN, SETTING, AND PATIENTS: Prospective, unblinded, multicenter controlled trial of 791 ARF patients in 21 general intensive care units in France using concealed randomization conducted from December 14, 1998, through December 31, 2002. To be included, patients had to be at least 18 years, hemodynamically stable, receiving mechanical ventilation, and intubated and had to have a partial pressure of arterial oxygen (PaO2) to fraction of inspired oxygen (FIO2) ratio of 300 or less and no contraindications to lying prone. INTERVENTIONS: Patients were randomly assigned to prone position placement (n = 413), applied as early as possible for at least 8 hours per day on standard beds, or to supine position placement (n = 378). MAIN OUTCOME MEASURES: The primary end point was 28-day mortality; secondary end points were 90-day mortality, duration of mechanical ventilation, incidence of ventilator-associated pneumonia (VAP), and oxygenation. RESULTS: The 2 groups were comparable at randomization. The 28-day mortality rate was 32.4% for the prone group and 31.5% for the supine group (relative risk [RR], 0.97; 95% confidence interval [CI], 0.79-1.19; P = .77). Ninety-day mortality for the prone group was 43.3% vs 42.2% for the supine group (RR, 0.98; 95% CI, 0.84-1.13; P = .74). The mean (SD) duration of mechanical ventilation was 13.7 (7.8) days for the prone group vs 14.1 (8.6) days for the supine group (P = .93) and the VAP incidence was 1.66 vs 2.14 episodes per 100-patients days of intubation, respectively (P = .045). The PaO2/FIO2 ratio was significantly higher in the prone group during the 28-day follow-up. However, pressure sores, selective intubation, and endotracheal tube obstruction incidences were higher in the prone group. CONCLUSIONS: This trial demonstrated no beneficial outcomes and some safety concerns associated with prone positioning. For patients with hypoxemic ARF, prone position placement may lower the incidence of VAP.

Acute Disease↗
PubMed2005

Detection of amiodarone-induced pulmonary toxicity in supine and prone positions: high-resolution computed tomography study.

BACKGROUND: The aim of the present study was to describe the effectiveness and feasibility of high-resolution computed tomography (HRCT) in patients in supine and prone positions to detect amiodarone-induced pulmonary toxicity (APT). With regard to the possible differential diagnosis, our second goal was to emphasize the clinical value of HRCT with the patients in supine and prone positions compared with other paraclinical tests. METHODS AND RESULTS: Thoracic HRCT taken in both positions for 23 patients who were administrated amiodarone were prospectively evaluated in the current study. High-resolution computed tomography scans obtained with the patient in a prone position were helpful in differentiating dependent opacity from lung disease in 11 out of 23 patients. In another 4 patients, HRCT scans obtained with the patient in a prone position were useful in confirming the presence of subtle ground-glass opacities, considered as APT. Combination of HRCT in supine and prone positions provided a more reproducible method for evaluating the global extent of APT than other paraclinical tests. CONCLUSIONS: High-resolution computed tomography used in prone positions as well as a supine position could be an effective technique for reducing false-positive results in detection of APT and preventing the clinically serious pulmonary adverse effects by amiodanone.

Adult↗
PubMed1996

Comparison of the kidney dose between supine and prone position for pelvic and periaortic irradiation.

We compared the doses received by the kidney in supine and prone positions for pelvic and periaortic irradiation. Kidney locations were verified by CT images taken with patients in the same position as during the treatment. Due to the shift of the kidney anteriorly during prone position, treatment in supine position delivered a much lower dose to most of the kidney than treatment in the prone position. Therefore, for periaortic irradiation treatment, the supine position should be considered to minimize the dose to the kidneys, even though the prone position with a belly board can reduce the dose to the small bowel.

Humans↗
PubMed1998

Effects of the prone position on respiratory mechanics and gas exchange during acute lung injury.

We studied 16 patients with acute lung injury receiving volume-controlled ventilation to assess the relationships between gas exchange and respiratory mechanics before, during, and after 2 h in the prone position. We measured the end-expiratory lung volume (EELV, helium dilution), the total respiratory system (Cst,rs), the lung (Cst,L) and the thoracoabdominal cage (Cst,w) compliances (end-inspiratory occlusion technique and esophageal balloon), the hemodynamics, and gas exchange. In the prone position, PaO2 increased from 103.2 +/- 23.8 to 129.3 +/- 32.9 mm Hg (p < 0.05) without significant changes of Cst,rs and EELV. However, Cst,w decreased from 204.8 +/- 97.4 to 135.9 +/- 52.5 ml/cm H2O (p < 0.01) and the decrease was correlated with the oxygenation increase (r = 0.62, p < 0.05). Furthermore, the greater the baseline supine Cst,w, the greater its decrease in the prone position (r = 0.82, p < 0.01). Consequently, the oxygenation changes in the prone position were predictable from baseline supine Cst,w (r = 0.80, p < 0.01). Returning to the supine position, Cst,rs increased compared with baseline (42.3 +/- 14.4 versus 38.4 +/- 13.7 ml/cm H2O; p < 0.01), mainly because of the lung component (57.5 +/- 25.1 versus 52.4 +/- 23.3 ml/cm H2O; p < 0.01). Thus, (1) baseline Cst,w and its changes may play a role in determining the oxygenation response in the prone position; (2) the prone position improves Cst,rs and Cst,L when the supine position is resumed.

Adult↗
PubMed2004

[Comparison of incomplete (135 degrees ) and complete prone position (180 degrees ) in patients with acute respiratory distress syndrome. Results of a prospective, randomised trial].

BACKGROUND: Ventilation in the prone position is carried out for improvement of pulmonary gas exchange in patients with acute respiratory distress syndrome (ARDS). We compared the effects of an incomplete prone position (IPP, 135( degrees )) with a complete prone position (CPP, 180( degrees )) in patients with ARDS. PATIENTS AND METHODS: For this trial 59 patients with ARDS were randomly assigned and were positioned in a "cross-over" design: patients of group A were placed in IPP for 6 h and then immediately positioned in CPP for another 6 h. Patients in group B were positioned in reverse order. Blood gases, hemodynamic measurements, quasistatic respiratory compliance and assessments of side effects were performed before begin, 30 min and 6 h after first positioning, then 30 min and 6 h after second positioning and 2 after repositioning. RESULTS: Turning patients in IPP and CPP resulted in a significant increase in the arterial oxygenation index (p(a)O(2)/F(I)O(2)), but this effect was more pronounced in the CPP (before: 142+/-46 mm Hg, 6 h: 253+/-107 mm Hg) than in the IPP (before: 139+/-54 mm Hg, 6 h: 206+/-75 mm Hg), and compliance was improved only in CPP. The improvement in arterial oxygenation persisted 2 h after repositioning in the supine position in both groups. The oxygenation responder rate was lower during the IPP (70.3%) in comparison with the CPP (84.0%, p<0.05). The incidence of side effects tended to be increased during the CPP. CONCLUSION: Incomplete prone position improves oxygenation in ARDS patients, but less effectively than a "classic" CPP. In these patients the use of a CPP should be preferred.

Aged↗
PubMed2002

Prone position as prevention of lung injury in comatose patients: a prospective, randomized, controlled study.

OBJECTIVE: Comatose patients frequently exhibit pulmonary function worsening, especially in cases of pulmonary infection. It appears to have a deleterious effect on neurologic outcome. We therefore conducted a randomized trial to determine whether daily prone positioning would prevent lung worsening in these patients. DESIGN: Prospective, randomized, controlled study. SETTING: Sixteen-bed intensive care unit. PATIENTS: Fifty-one patients who required invasive mechanical ventilation because of coma with Glascow coma scores of 9 or less. INTERVENTIONS: In the prone position (PP) group: prone positioning for 4 h once daily until the patients could get up to sit in an armchair; in the supine position (SP) group: supine positioning. MEASUREMENTS AND RESULTS: The primary end point was the incidence of lung worsening defined by an increase in the Lung Injury Score of at least 1 point since the time of randomization. The secondary end point was the incidence of ventilator-associated pneumonia (VAP). A total of 25 patients were randomly assigned to the PP group and 26 patients to the SP group. The characteristics of the patients from the two groups were similar at randomization. The incidence of lung worsening was lower in the PP group (12%) than in the SP group (50%) ( p=0.003). The incidence of VAP was 20% in the PP group and 38.4% in the SP group ( p=0.14). There was no serious complication attributable to prone positioning, however, there was a significant increase of intracranial pressure in the PP. CONCLUSION: In a selected population of comatose ventilated patients, daily prone positioning reduced the incidence of lung worsening.

Chi-Square Distribution↗
PubMed1998

Auditory arousal thresholds are higher when infants sleep in the prone position.

OBJECTIVE: To evaluate the possibility that infants sleeping in the prone position have higher arousal thresholds to auditory challenges than when sleeping in the supine position. STUDY DESIGN: Polygraphic recordings were performed for 1 night in 25 healthy infants with a median age of 9 weeks. The infants were exposed to white noises of increasing intensities while sleeping successively in the prone and supine positions, or vice versa. Arousal thresholds were defined by the auditory stimuli needed to induce polygraphic arousals. RESULTS: Three infants were excluded from the study because they awoke while their position was being changed. For the 22 infants included in the analysis, more intense auditory stimuli were needed to arouse the infants in the prone position than those in the supine body position (p = 0.011). Arousal thresholds were higher in the prone than in the supine position in 15 infants; unchanged in 4 infants; and lower in the prone position in 3 infants (p = 0.007). CONCLUSIONS: Infants show higher arousal thresholds to auditory challenges when sleeping in the prone position than when sleeping in the supine position. The finding could be relevant to mechanisms concerned with the reported association between sudden deaths and the prone sleeping position in infants.

Auditory Threshold↗
PubMed2004

The 'modified prone position': a new approach for treating pre-vesical stones with extracorporeal shock wave lithotripsy.

OBJECTIVE: To investigate the utility of a new 'modified-prone' position for treating pre-vesical stones with extracorporeal shock wave lithotripsy (ESWL), usually considered an acceptable and effective treatment for such stones, but for which many different body positions have been used in an attempt to increase its efficacy. PATIENTS AND METHODS: The study included 268 consecutive patients with a solitary pre-vesical stone who underwent ESWL either prone (69) or in the modified-prone position (199) between May 1999 and August 2001. Only those with one stone between the ureteric orifice and 1 cm proximal to the vesico-ureteric junction were included. In each case the stone diameter, days to stone clearance, number of shock waves applied per treatment, and number of sessions required to become stone-free were recorded. If the treatment failed this was also noted. Success rates in the prone and modified-prone groups were compared and analysed to assess which of the variables influenced success with ESWL. RESULTS: After ESWL, 95.5% of the 268 patients were stone-free; the rates in the prone and modified-prone groups were 89.9% and 97.5%, respectively (P = 0.015). The probability of success with ESWL therapy for pre-vesical calculi in modified-prone position was about five times (odds ratio 4.56, 95% confidence interval 1.2-17.7) greater than that expected with when prone. The modified-prone position was an independent factor most significantly influencing success with ESWL in these patients. CONCLUSION: The modified-prone position for ESWL is a new and very effective way to treat patients with pre-vesical stones.

Adolescent↗
PubMed1998

Effects of maternal prone position on the umbilical arterial flow.

OBJECTIVE: The objective of our study was to clarify the effect of the maternal prone position on the feto-placental flow. In this position, the uterine compression of the large maternal vessels was expected to be completely eliminated. METHODS: Twenty-three normal pregnant women were cross-sectionally examined in the supine, the left lateral, the right lateral and the prone position. The systolic/diastolic ratios for the umbilical artery were calculated for each position. RESULTS: The umbilical arterial systolic/diastolic ratio in the prone position significantly decreased compared with that in the supine position. The left and right lateral position showed no significant change in the systolic/diastolic ratio. CONCLUSION: The maternal prone position can provide complete relief of uterine compression of the large maternal vessels.

Cross-Sectional Studies↗
PubMed2002

Prone position for the prevention of lung infection.

Pulmonary infection is frequent in brain injured patients. It has been identified as an independent predictor of unfavorable neurological outcome, calling for attempts of prevention. We recently evaluated intermittent prone positioning for the prevention of ventilator-associated pneumonia (VAP) in comatose brain injured patients, in a randomized study. 25 patients were included in the prone position (PP) group: they were positioned on prone four hours once daily until they could get up to sit in an armchair; 26 patients were included in the supine position (SP) group. The main characteristics of the patients from the two groups were similar at randomization. The primary end-point was the incidence of lung worsening, defined by an increase in the Lung Injury Score by at least one point since the time of randomization. The incidence of lung worsening was lower in the PP group (12%) than in the SP group (50%) (p=0.003). The incidence of VAP was 38.4% in the SP group and 20% in the PP group (p=0.14). There was no serious complication attributable to prone positioning. In conclusion, the beneficial effect of prone positioning for prevention of lung infection in brain injured patients is not well established. However, in those patients, prone positioning is able to avoid the worsening of pulmonary function, especially in oxygenation.

Brain Injuries↗
PubMed1978

Pulmonary shunts in the prone position.

Pulmonary shunting (Qs/Qt with the FIO2 = 1) was determined in ten young healthy non-obese patients prior to anaesthesia, 30 min after induction in the supine position and 1 h later during surgery in the prone position. Respiration was spontaneous in awake patients and was controlled following the induction of anaesthesia. Halothane was the primary anaesthetic and tubocurarine provided muscle relaxation. Mean PaCO2 was 40.7, 29.5 and 27.9 mmHg respectively in the three study periods. The shunt remained unchanged at 5.7 +/- 0.8% in the awake patients, and 6.0 +/- 1.1% during anaesthesia in the supine position, and 5.2 +/- 1.2% during anesthesia and surgery in the prone position. It is concluded that in this population the prone position does not alter the magnitude of the pulmonary shunt even in those patients who develop shunts of over 10% after the induction of anaesthesia.

Adult↗