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[Change of position and the decrease in the cases of sudden infant death syndrome in Navarra].

The prone position during sleep has been described as the most important risk factor in relationship to sudden infant death syndrome (SIDS). The prevalence of infants that sleep in the prone position and its relationship with SIDS has not been studied in our country. A survey was performed in a population of children born in Navarra between February 1, 1992 and February 1, 1993. We found that 86.5% of these children sleep in the prone position, 5.6% in the supine position and 3.5% on their side. In March 1993 a campaign was begun that recommended that the prone position not be used for infants from the time of birth until 6 months of age. After this campaign, in a sample of 441 children, born between May 1, 1993 and May 1, 1994, only 38.3% of the infants continued to sleep in the prone position, while 46% did so supine and 9% slept on their side. The number of deaths in Navarra as a result of SIDS during the period of 1985 through 1993 was 1.3% of live births with a mean of 6.3 deaths/year. The number of infant deaths after the change of sleeping position, in 1994, was 0.42% of live births, with 2 deaths as a result of SIDS during this year. In Navarra, the decrease in the number of infants sleeping in the prone position has been accompanied by a significant decline in the number of deaths due to SIDS.

Humans↗

Subdural intracranial pressure, cerebral perfusion pressure, and degree of cerebral swelling in supra- and infratentorial space-occupying lesions in children.

UNLABELLED: To our knowledge comparative studies of intracranial pressure (ICP) and degree of cerebral swelling during craniotomy for supratentorial or infratentorial space occupying lesion in children are not available. In this prospective study subdural ICP, cerebral perfusion pressure (CPP), dural tension, and the degree of cerebral swelling were analysed in supine and prone positioned children subjected to craniotomy for space occupying lesions. MATERIAL AND METHOD: 48 children with space occupying tumours were subjected to either isoflurane/nitrous oxide 50%/fentanyl (n = 22) or propofol/fentanyl/air/oxygen (n = 26). 25 children were operated supratentorially in supine position, while 23 patients were operated infratentorially in the prone position. Subdural ICP, mean arterial blood pressure (MABP), and CPP were measured just before opening of the dura. Dural tension was estimated before opening of dura, and the degree of cerebral swelling was estimated after opening of dura. RESULTS: The age and weight of children anaesthetised with isoflurane in the prone position were significantly lower than the propofol anaesthetised groups. No significant inter-group differences as regards tumour size, midline shift, rectal temperature, MABP or PaCO2 were found. ICP in prone positioned children averaged 16.9 mm Hg against 9.0 mm Hg in supine positioned children (p < 0.001). In prone positioned children the dura was significantly tenser, and the degree of brain swelling after opening of dura was significantly more pronounced. No significant difference as regard ICP was disclosed when isoflurane/nitrous oxide/fentanyl and propofol/ fentanyl anaesthetized children were compared, but MABP and CPP were significantly lower in isoflurane anaesthetised children. CONCLUSION: In children with cerebral tumours ICP is higher, and the degree of cerebral swelling more pronounced in the prone-compared with supine positioned children. Choice of anaesthesia did not influence ICP, but CPP was significantly lower during isoflurane anaesthesia.

Blood Pressure↗

Infant position in neonates receiving mechanical ventilation.

BACKGROUND: Several body positions other than standard supine position have been used in patients undergoing intensive care for reducing the incidence of pressure ulcers of the skin, contractures or ankylosis and for improving the patient's well being. In patients from different age groups undergoing mechanical ventilation (MV), it has been observed that particular positions such as prone position may improve some respiratory parameters. Benefits from these positions have not been clearly defined in Neonatology, a field where it is common that patients require mechanical ventilation sometimes during extended time periods. OBJECTIVES: To assess the effects on both short and long-term outcomes of different positioning of newborn infants receiving MV. SEARCH STRATEGY: Databases searched (up to January 2002) were the Oxford Database of Perinatal Trials, CINAHL, MEDLINE, EMBASE and Cochrane Controlled Trials Register (The Cochrane Library, Issue 1, 2002). Hand searches of proceedings of the Society for Pediatric Research from 1990 to January 2002 were used to identify unpublished studies. SELECTION CRITERIA: Randomised or quasi randomised clinical trials comparing different positions in newborns receiving mechanical ventilation. DATA COLLECTION AND ANALYSIS: Three independent and unblinded reviewers assessed the trials for inclusion in the review and extracted the data. Data were double-checked and entered into the Review Manager software. MAIN RESULTS: Ten trials involving 164 infants were included in this review. Several positions were compared: prone vs. supine, prone vs. lateral right, lateral right vs. supine, lateral left vs. supine, lateral right vs. lateral left and good lung dependent vs. good lung uppermost. Apart from one of the two studies that compared lateral right vs. lateral left positions, all the included studies had a crossover design. Comparing prone vs. supine position, an increase in arterial P02 in the prone position of between 2.75 and 9.72 mm Hg (95%CI) was observed (one trial). When % hemoglobin oxygen saturation was measured with pulse oximetry, improvement in the prone position was from 1.17 to 4.36% (typical effect based on four trials). It was not possible to establish whether this effect remained once the intervention was stopped. Negative effects from the interventions were not described, although this issue was not studied enough. Effects of position on other outcomes were not statistically significant; however, these cannot be excluded considering the small numbers that were studied. REVIEWER'S CONCLUSIONS: The prone position was found to slightly improve the oxygenation in neonates undergoing mechanical ventilation. However, we found no evidence concerning whether particular body positions during mechanical ventilation of the neonate are effective in producing sustained and clinically relevant improvements.

Humans↗

Effect of posture on gastro-oesophageal reflux in the newborn.

The effect of posture on gastro-oesophageal reflux was studied by giving 72 orogastric tube feeds to 18 low birthweight babies. Each infant was studied in each of 4 positions: prone, supine, right, and left lateral. Brilliant blue was added to feeds and reflux was determined by staining of a cotton thread opposite the holes in a feeding tube passing from the nose to the distal oesophagus. A comparison of the prone and supine positions showed that significantly less reflux occurred in the prone position.

Enteral Nutrition↗

An assessment of the impact of public health activities to reduce the prevalence of the prone sleeping position during infancy: the Tasmanian Cohort Study.

BACKGROUND: An intervention to reduce the prevalence of the prone sleeping position during infancy was implemented in Tasmania particularly from 1991 onward. The purpose of this report is to assess the impact of public health activities in promoting avoidance of the prone infant sleeping position among cohort study participants. METHODS: The prospective cohort study involved the one-fifth of Tasmanian live births who are assessed perinatally as being at higher risk for Sudden Infant Death Syndrome (SIDS). From 1 January 1988 until 30 April 1992, 5,403 infants participated in the hospital (4 days postnatal age) and home interviews (5 weeks postnatal age) (88% of eligible infants). After the finding that cohort infants who usually slept prone were at significantly greater risk for SIDS, additional questions on awareness and choice of infant sleep position were asked. RESULTS: The proportion of infants usually sleeping prone declined from 29.9% in the cohort prior to publication of the cohort findings (1 May 1988-30 April 1991) to 5.4% in the post publication cohort (1 May 1991-30 April 1992), RR = 0.18 (0.15, 0.22). Teenage motherhood was associated with non-awareness (RR = 2.39 (1.41, 3.24)) of an association between prone position and SIDS. After adjusting for maternal age, nonawareness remained positively associated with maternal smoking, maternal education (< Year 12), and paternal unemployment, while mothers who read books to prepare for the baby and who were married were more likely to be aware. In the period after the cohort study publication, the most common reasons given for the usual prone position were that the baby preferred that position and slept better. CONCLUSION: Public health activities to reduce the prevalence of the prone sleeping position have had a significant impact, with a dramatic reduction in the proportion of cohort infants usually sleeping prone. The identification of characteristics of nonaware mothers and the reasons for choosing a particular sleeping position will be used to maintain and improve health education in this area.

Child, Preschool↗

Infant position in neonates receiving mechanical ventilation.

BACKGROUND: Several body positions other than standard supine position have been used in patients undergoing intensive care for reducing the incidence of pressure ulcers of the skin, contractures or ankylosis and for improving the patient's well being. In patients from different age groups undergoing mechanical ventilation (MV), it has been observed that particular positions, such as prone position, may improve some respiratory parameters. Benefits from these positions have not been clearly defined in critically ill newborns who may require mechanical ventilation for extended periods of time. OBJECTIVES: To assess the effects of different positioning of newborn infants receiving MV on short term respiratory outcomes and complications of prematurity. SEARCH STRATEGY: Databases searched (up to May 2006) were the Oxford Database of Perinatal Trials, CINAHL, MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2006). Hand searches of proceedings of the Society for Pediatric Research from 1990 to May 2006 were used to identify unpublished studies. SELECTION CRITERIA: Randomised or quasi randomised clinical trials comparing different positions in newborns receiving mechanical ventilation. DATA COLLECTION AND ANALYSIS: Three independent and unblinded reviewers assessed the trials for inclusion in the review and extracted the data. Data were double-checked and entered into the Review Manager software. MAIN RESULTS: Eleven trials involving 206 infants were included in this review. Several positions were compared: prone vs. supine, prone vs. lateral right, lateral right vs. supine, lateral left vs. supine, lateral right vs. lateral left and good lung dependent vs. good lung uppermost. Apart from one of the two studies that compared lateral right vs. lateral left positions, and one comparing prone vs. supine position, all the included studies had a crossover design. Comparing prone vs. supine position, an increase in arterial P02 in the prone position of between 2.75 and 9.72 mm Hg (95% CI) was observed (one trial). When % hemoglobin oxygen saturation was measured with pulse oximetry, improvement in the prone position was from 1.18 to 4.36% (typical effect based on four trials). In addition, there was a slight improvement in the number of episodes of desaturation. It was not possible to establish whether this effect remained once the intervention was stopped. Negative effects from the interventions were not described, although this issue was not studied in sufficient detail. Effects of position on other outcomes were not statistically significant; however, either positive nor negative effects cannot be excluded considering the small numbers that were studied. AUTHORS' CONCLUSIONS: The prone position was found to slightly improve the oxygenation in neonates undergoing mechanical ventilation. However, we found no evidence concerning whether particular body positions during mechanical ventilation of the neonate are effective in producing sustained and clinically relevant improvements.

Humans↗

[Effect of kinetic therapy on the course of treatment of patients with post-traumatic lung failure].

This study was conducted to investigate the effects of intermittent prone positioning of patients with post-traumatic respiratory failure (paO2/FiO2 < 280 mm Hg) in comparison with conventional therapy in a supine position. Although the severity of injury of the prone-positioned patients was much higher (ISS 35.8 vs 24.5), the ventilation time (32 vs 31 days) and ICU stay (39 vs 36 days) were similar to patients treated in the supine position. Besides the beneficial effect of prone positioning on oxygenation, for the first time we have evidence that prone positioning improves the outcome of patients with post-traumatic respiratory failure.

Adult↗

Effect of nursing position on incidence, type, and duration of clinically significant apnoea in preterm infants.

AIM: To investigate whether nursing position has any effect on the frequency, type, and duration of apnoeas in preterm infants. METHOD: Thirty five preterm infants were entered into a crossover study and underwent polygraphic monitoring in each of two positions, prone and supine, the initial position being randomly allocated. Four parameters were recorded: nasal airflow, respiratory effort, electrocardiogram (ECG), and oxygen saturation. Each infant was studied in the two positions on the same day and each infant was studied only once. The studies were carried out on the neonatal intensive care unit. RESULTS: The infants were found to have significantly more central and mixed apnoeas in the supine than in the prone position. In addition, the severity of mixed apnoeas in terms of the duration of accompanying bradycardias and desaturations was greater in the supine than in the prone position (median difference 5.1 seconds in both instances). When considering the type of apnoea in relation to the duration, it was found that of those less than 20 seconds in duration there was a greater proportion that were central (25%) compared with the proportion of central (5%) apnoeas that were longer than 20 seconds. Of all the apnoeas that were less than 20 seconds in length, 16% were obstructive and 59% were mixed, whereas of the apnoeas greater than 20 seconds, 13% were obstructive and 82% were mixed. CONCLUSIONS: It appears that in addition to improving measures of lung function, the adoption of the prone nursing position for preterm infants may reduce associated problems of apnoea of prematurity.

Apnea↗

Prone sleep position and the sudden infant death syndrome in King County, Washington: a case-control study.

OBJECTIVE: To determine whether the prone sleep position was associated with an increased risk of the sudden infant death syndrome (SIDS). STUDY DESIGN: Population-based case-control study. PARTICIPANTS: Case subjects were infants who died of SIDS in King County, Washington. Control subjects were randomly selected infants born in King County. Up to four control subjects were matched on date of birth to each case subject. METHODS: During the study period, November 1992 through October 1994, sleep-position data were collected on infants who died of SIDS by the King Count Medical Examiner's Office during their investigation of the deaths. Parents of infants chosen as control subjects were contacted by telephone, and sleep position information was obtained. Infants who usually slept on their abdomen were classified as sleeping prone; those who usually slept on the side or back were categorized as sleeping nonprone. The adjusted odds ratio for prone sleep position as a risk factor for SIDS was calculated with conditional logistic regression after control for race, birth weight, maternal age, maternal marital status, household income, and maternal cigarette smoking during pregnancy. RESULTS: Sleep position data were collected on 47 infants with SIDS (77% of eligible infants) and 142 matched control subjects; 57.4% of infants who died of SIDS usually slept prone versus 24.6% of control subjects (p < 0.00001). The unadjusted odds ratio for prone sleep position as a risk factor for SIDS was 4.69 (95% confidence interval: 2.17, 10.17). After control for potentially confounding variables, the adjusted odds ratio for prone sleep position was 3.12 (95% confidence interval: 1.08, 9.03). CONCLUSION: Prone sleep position was significantly associated with an increased risk of SIDS among a group of American infants.

Adult↗

Interexaminer reliability of activator methods' relative leg-length evaluation in the prone extended position.

OBJECTIVE: To investigate the interexaminer reliability of the prone extended relative leg-length check as described by Activator Methods, Inc. SUBJECTS: Thirty-four subjects were selected from a pool of 52 consecutive patients visiting a private chiropractic office. METHODS: Exclusion criteria included congenital or acquired conditions known to affect lower extremity length and inability to lie prone for a 10-minute period. Two experienced chiropractors who specialize in Activator Methods and are "advanced-proficiency rated" by Activator Methods, Inc. assessed each patient in random order for leg length inequality. Findings were recorded as left short leg, equal leg length, or right short leg. RESULTS: The data for 34 subjects were organized in a 3 x 3 contingency table. Total agreement was 85%. A simple, unweighted kappa value yielded kappa = 0.66. A disproportionately greater number of right short leg findings than left short leg findings were observed by both examiners. In only 2 instances were equal leg lengths observed, and both were detected by the same examiner. Because examiners found only 2 of 34 subjects with equal leg lengths, several secondary analyses involving data reductions were conducted. The resulting kappa values were similar to the 3 x 3 analysis. CONCLUSION: There was good reproducibility between 2 examiners by using the Activator Method to detect leg length inequality in the prone extended position. This study does not address the validity or clinical significance of the measurement method. Future studies should include larger numbers, a wider variety of subjects, and a diversity of examiners.

Adult↗

Evaluation of pupillary block component in angle-closure glaucoma.

To evaluate the amount of the pupillary block component in primary angle-closure glaucoma, the dark-room prone-position test was carried out in 30 eyes of 20 primary angle-closure glaucoma patients, before and one month after argon laser iridotomy. The pupillary block component in the prone position (5.8 +/- 5.6 mmHg), which is the amount of reduction in IOP rise in the post-laser dark-room prone-position test, composed 67.8% of the IOP rise in the pre-laser dark-room prone-position test (8.6 +/- 5.6 mmHg). The amount of the pupillary block component correlated significantly with the IOP rise in the pre-laser dark-room prone-position test (r = 0.880, P < 0.001). The amount of the non-pupillary block component was relatively constant and correlated poorly with the IOP rise in the pre-laser dark-room prone-position test (r = 0.163, P = 0.386). The pupillary block component was significantly larger than the non-pupillary block component in the eyes with an IOP rise of > or = 7 mmHg in the pre-laser dark-room prone-position test (P < 0.01). The dark-room prone-position test could be useful in evaluating the pupillary block component in angle-closure glaucoma eyes and helpful in making a decision for laser iridotomy.

Adult↗

Propofol pharmacokinetics in a dwarfism patient.

Pharmacokinetic information is important to control anesthetic depth. However, there are few available pharmacokinetic data of propofol in dwarfism patients. We anesthetized a dwarfism patient who underwent spinal decompression, and investigated the pharmacokinetics of propofol. The patient was a 40-year-old man suffering from muscle weakness and numbness in the arms. The operation consisted of two stages; anterior approach in the supine position and posterior approach in the prone position. We also obtained arterial blood for pharmacokinetic analysis. Distribution volume at steady-state and clearance in the supine position was 180 and 0.92 l min- 1, respectively, and in the prone position 127 and 0.74 l min- 1, respectively, in spite of a continuous infusion of dopamine. The data in the supine position were well predicted by Gepts' parameters (used in Diprifusor Zeneca Ltd, Cheshire, UK), which means the target-controlled infusion (TCI) technique can be available in the supine position, while attention is necessary to avoid overdosing when a patient is placed in the prone position.

Adult↗

An overview of retrospective case-control studies investigating the relationship between prone sleeping position and SIDS.

A critical overview of 19 case-control studies that have investigated the relationship between prone sleeping position and sudden infant death syndrome (SIDS) is presented. Issues relating to the non-comparability of the studies are described in terms of: (i) case definition; (ii) selection of controls; (iii) quality of the sleeping position data; (iv) recall bias; and (v) adjustment for confounding factors. All studies showed a positive association (2 out of the 19 studies were not significant) between prone sleeping position and SIDS. Meta-analysis techniques applied to six of these studies, based on 'usual' sleeping position in cases and population representative controls, has confirmed an overall higher risk of SIDS in infants who usually sleep prone. The most common odds ratio for an association between prone sleeping position and SIDS was 2.72 (95% confidence interval 2.27-3.26). The extent to which the methodological problems of retrospective case-control studies interfere with our interpretations of this association are discussed.

Bias↗

Gravitational independence of single-breath washout tests in recumbent dogs.

To examine the mechanisms of lung filling and emptying, Ar-bolus and N2 single-breath washout tests were conducted in 10 anesthetized dogs (prone and supine) and in three of those dogs with body rotation. Transpulmonary pressure was measured simultaneously, allowing identification of the lung volume above residual volume at which there was an inflection point in the pressure-volume curve (VIP). Although phase IV for Ar was upward, phase IV for N2 was small and variable, especially in the prone position. No significant prone to supine differences in closing capacity for Ar were seen, indicating that airway closure was generated at the same lung volumes. The maximum deflections of phase IV for Ar and N2 from extrapolated phase III slopes were smaller in the prone position, suggesting more uniform tracer gas concentrations across the lungs. VIP was smaller than the closing volume for Ar, which is consistent with the effects of well-developed collateral ventilation in dogs. Body rotation tests in three dogs did not generally cause an inversion of phase III or IV. We conclude that in recumbent dogs regional distribution of ventilation is not primarily determined by the effect of gravity, but by lung, thorax, and mediastinum interactions and/or differences in regional mechanical properties of the lungs.

Animals↗

Prone and supine positioning effects on energy expenditure and behavior of low birth weight neonates.

The effect of body position (supine v prone) on energy expenditure and behavior of 42 healthy low birth weight (920 to 1,760 g) infants was evaluated in 66 studies. Each infant was randomly assigned to the supine or prone position for the first three-hour epoch; the position was reversed for the second three-hour epoch. The difference in energy expenditure and the percentage of time in active sleep, quiet sleep, and wakefulness between the two positions was computed. The median difference (supine minus prone) in overall energy expenditure between positions was +3.1 kcal/kg/d (interquartile range 0.6 to 6.5; P less than .001). When only periods of active sleep were analyzed, the median difference in energy expenditure remained significant, the supine position being higher than prone by +2.6 kcal/kg/d (interquartile range 0.1 to 4.8; P less than .001). In the supine position, the time awake was 5.7% higher (interquartile range 1.8 to 17.4; P less than .001) than in the prone position. The percentage of time in active sleep was not significantly different between the positions, hence quiet sleep decreased in the supine position. In summary, when low birth weight infants are changed from the supine to the prone position, energy expenditure decreases, time spent in quiet sleep increases, and time spent awake decreases. These data suggest that prone is the position of choice for the low birth weight infant.

Child Behavior↗

Improved oxygenation utilizing a prone positioner in patients with acute respiratory distress syndrome.

OBJECTIVES: (a) To determine whether placing patients with acute respiratory distress syndrome in the prone position by a light-weight portable support frame improves oxygenation, (b) whether one can determine which patients benefit from prone positioning, and (c) to determine an effective technique for prone positioning of patients. DESIGN: Prospective, controlled trial without blinding. SETTING: Medical intensive care units in two urban university-affiliated hospitals. PATIENTS: Fifteen patients meeting a standard definition for acute respiratory distress syndrome were studied prospectively. Each patient acted as his own control for purposes of comparison. INTERVENTION: Patients were assigned randomly to begin in either supine or prone positions. The positioning frame was used to turn patients from one position to the other, and oxygenation, ventilation, respiratory mechanics, and hemodynamics were measured. RESULTS: Significantly better oxygenation was seen in the prone positions than in the supine (P < 0.05). In the overall population there was a decrease in AaDO2 of 21 mmHg when the patients were placed prone. The groups were then divided into responders (n = 9) and nonresponders (n = 6). There were significant differences between the groups (but not between positions) regarding PaO2, baseline, PaCO2, pulmonary artery pressures, and peak inspiratory pressures on the ventilator and in ICU length of stay and time on mechanical ventilatory support. CONCLUSION: Prone positioning improves oxygenation in the majority of patients studied and can be achieved relatively easily.

Adult↗

A new hypothesis for sudden infant death syndrome: the occlusion of vertebral arteries as a major cause.

Many factors, such as prematurity, low weight and minor infection, may predispose to Sudden Infant Death Syndrome (SIDS) but not cause it. It is suggested that the ultimate act of dying is due to the occlusion of one or both vertebral arteries triggered by the position of the head and cervical spine. When the head is turned to one side, the ipsilateral vertebral artery may be occluded at mid-cervical level along its length, or the contra lateral artery at atlanto-axial level or on both sides with the head in the initial position. Extension of cervical spine, with or without rotation, may produce obstruction of one or both vertebral arteries. If the degree, the levels and duration of occlusion are exceeded, particularly if there is a degree of failure of the collateral circulation (including one from carotid arteries via posterior communicating arteries), this can lead to prolonged apnoea, a 'near-miss' or cot death. The factors which may predispose to SIDS among others are hypoplasia or 'unexercised' vertebral arteries (in utero) and/or hypermobility of the immature cervical spine with lax joint capsules and ligaments. These factors allow the undue stretch or kinking of the vertebral arteries resulting in occlusion when the head or cervical spine are turned. The hypothesis explains the reduction of mortality of SIDS in infants in sleeping supine position to those in the prone position. In prone position, the infant's head is rotated 90 degrees which may put stress on atlas and axis thus occlude vertebral arteries by stretching and kinking. Infants under 6 months are unable to change position unaided so duration of obstruction is an aggravating element. These factors are about 50% less in the supine position.

Journal Article↗