The Effect of 10-degree leg elevation and 30-degree head elevation on body displacement and sacral interface pressures over a 2-hour period

Background Head elevation can restore airway patency during anesthesia, although its effect may be offset by concomitant bite opening or accidental neck flexion. The aim of this study is to examine the effect of head elevation on the passive upper airway collapsibility during propofol anesthesia. Method Twenty male subjects were studied, randomized to one of two experimental groups: fixed-jaw or free-jaw. Propofol infusion was used for induction and to maintain blood at a constant target concentration between 1.5 and 2.0 μg/ml. Nasal mask pressure (PN) was intermittently reduced to evaluate the upper airway collapsibility (passive PCRIT) and upstream resistance (RUS) at each level of head elevation (0, 3, 6, and 9 cm). The authors measured the Frankfort plane (head flexion) and the mandible plane (jaw opening) angles at each level of head elevation. Analysis of variance was used to determine the effect of head elevation on PCRIT, head flexion, and jaw opening within each group. Results In both groups the Frankfort plane and mandible plane angles increased with head elevation (P < 0.05), although the mandible plane angle was smaller in the free-jaw group (i.e., increased jaw opening). In the fixed-jaw group, head elevation decreased upper airway collapsibility (PCRIT ~ -7 cm H₂O at greater than 6 cm elevation) compared with the baseline position (PCRIT ~ -3 cm H₂O at 0 cm elevation; P < 0.05). Conclusion : Elevating the head position by 6 cm while ensuring mouth closure (centric occlusion) produces substantial decreases in upper airway collapsibility and maintains upper airway patency during anesthesia.

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Effects of unconsciousness during spinal immobilization on tissue-interface pressures: A randomized controlled trial comparing a standard rigid spineboard with a newly developed soft-layered long spineboard

Injury ◽

10.1016/j.injury.2014.06.006 ◽

2014 ◽

Vol 45 (11) ◽

pp. 1741-1746 ◽

Cited By ~ 8

Author(s):

Baukje Hemmes ◽

Peter R.G. Brink ◽

Martijn Poeze

Keyword(s):

Randomized Controlled Trial ◽

Controlled Trial ◽

Randomized Controlled ◽

Spinal Immobilization ◽

Tissue Interface ◽

Interface Pressures

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Effects of Head Posture on Cerebral Hemodynamics: Its Influences on Intracranial Pressure, Cerebral Perfusion Pressure, and Cerebral Oxygenation

Neurosurgery ◽

10.1227/01.neu.0000108639.16783.39 ◽

2004 ◽

Vol 54 (3) ◽

pp. 593-598 ◽

Cited By ~ 117

Author(s):

Ivan Ng ◽

Joyce Lim ◽

Hwee Bee Wong

Keyword(s):

Mean Arterial Pressure ◽

Head Injury ◽

Intracranial Pressure ◽

Cerebral Perfusion ◽

Perfusion Pressure ◽

Cerebral Oxygenation ◽

Closed Head Injury ◽

Head Posture ◽

Head Elevation ◽

Closed Head

Abstract OBJECTIVE Severely head-injured patients have traditionally been maintained in the head-up position to ameliorate the effects of increased intracranial pressure (ICP). However, it has been reported that the supine position may improve cerebral perfusion pressure (CPP) and outcome. We sought to determine the impact of supine and 30 degrees semirecumbent postures on cerebrovascular dynamics and global as well as regional cerebral oxygenation within 24 hours of trauma. METHODS Patients with a closed head injury and a Glasgow Coma Scale score of 8 or less were included in the study. On admission to the neurocritical care unit, a standardized protocol aimed at minimizing secondary insults was instituted, and the influences of head posture were evaluated after all acute necessary interventions had been performed. ICP, CPP, mean arterial pressure, global cerebral oxygenation, and regional cerebral oxygenation were noted at 0 and 30 degrees of head elevation. RESULTS We studied 38 patients with severe closed head injury. The median Glasgow Coma Scale score was 7.0, and the mean age was 34.05 ± 16.02 years. ICP was significantly lower at 30 degrees than at 0 degrees of head elevation (P = 0.0005). Mean arterial pressure remained relatively unchanged. CPP was slightly but not significantly higher at 30 degrees than at 0 degrees (P = 0.412). However, global venous cerebral oxygenation and regional cerebral oxygenation were not affected significantly by head elevation. All global venous cerebral oxygenation values were above the critical threshold for ischemia at 0 and 30 degrees. CONCLUSION Routine nursing of patients with severe head injury at 30 degrees of head elevation within 24 hours after trauma leads to a consistent reduction of ICP (statistically significant) and an improvement in CPP (although not statistically significant) without concomitant deleterious changes in cerebral oxygenation.

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Head elevation and laryngeal mask airway Supreme insertion: A randomized controlled trial

Acta Anaesthesiologica Scandinavica ◽

10.1111/aas.13742 ◽

2020 ◽

Author(s):

Jun‐Young Park ◽

Jihion Yu ◽

Jun Hyuk Hong ◽

Jai‐Hyun Hwang ◽

Young‐Kug Kim

Keyword(s):

Randomized Controlled Trial ◽

Laryngeal Mask Airway ◽

Controlled Trial ◽

Laryngeal Mask ◽

Randomized Controlled ◽

Head Elevation ◽

Laryngeal Mask Airway Supreme

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Evaluating optic nerve head elevation

Journal of American Association for Pediatric Ophthalmology and Strabismus ◽

10.1016/j.jaapos.2021.08.275 ◽

2021 ◽

Vol 25 (4) ◽

pp. e73

Author(s):

Robert A. Avery ◽

Carmelina Trimboli-Heidler ◽

Stacy Pineles ◽

Gena Heidary

Keyword(s):

Optic Nerve ◽

Optic Nerve Head ◽

Head Elevation

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Impact of multilayered compression bandages on sub-bandage interface pressure: a model

Phlebology The Journal of Venous Disease ◽

10.1258/phleb.2010.009081 ◽

2011 ◽

Vol 26 (2) ◽

pp. 75-83 ◽

Cited By ~ 19

Author(s):

J Al Khaburi ◽

E A Nelson ◽

J Hutchinson ◽

A A Dehghani-Sanij

Keyword(s):

Mathematical Model ◽

Thick Wall ◽

Compression Bandage ◽

Leg Ulcers ◽

Interface Pressure ◽

Venous Leg Ulcers ◽

Compression Bandages ◽

Thick Cylinder ◽

The Difference ◽

Interface Pressures

Background Multi-component medical compression bandages are widely used to treat venous leg ulcers. The sub-bandage interface pressures induced by individual components of the multi-component compression bandage systems are not always simply additive. Current models to explain compression bandage performance do not take account of the increase in leg circumference when each bandage is applied, and this may account for the difference between predicted and actual pressures. Objective To calculate the interface pressure when a multi-component compression bandage system is applied to a leg. Method Use thick wall cylinder theory to estimate the sub-bandage pressure over the leg when a multi-component compression bandage is applied to a leg. Results A mathematical model was developed based on thick cylinder theory to include bandage thickness in the calculation of the interface pressure in multi-component compression systems. In multi-component compression systems, the interface pressure corresponds to the sum of the pressures applied by individual bandage layers. However, the change in the limb diameter caused by additional bandage layers should be considered in the calculation. Adding the interface pressure produced by single components without considering the bandage thickness will result in an overestimate of the overall interface pressure produced by the multi-component compression systems. At the ankle (circumference 25 cm) this error can be 19.2% or even more in the case of four components bandaging systems. Conclusion Bandage thickness should be considered when calculating the pressure applied using multi-component compression systems.

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