Mechanical Vibration in Ambulance Transport

doi:10.1111/j.1552-6909.1994.tb01905.x

Journal of Obstetric, Gynecologic & Neonatal Nursing

Volume 23, Issue 6, July 1994, Pages 457-463

https://doi.org/10.1111/j.1552-6909.1994.tb01905.x Get rights and content

Objective

To study the effects of mechanical vibration on neonates during ambulance transport.

Design

Study used an infant mannequin in an isolette and measured the vibration levels experienced during controlled ambulance transports.

Participants

Transport nurses and paramedics used a hospital‐based mobile intensive care unit (MICU).

Main Outcome Measure

Measured vibration levels at specific locations within the ambulance and isolette. Investigated nonstandard mattresses and additional modifications to the isolette that would dampen the vibration transferred to the neonate.

Results

The analysis of variance showed significant differences (p < .002) in the amount of vibration among the specific locations in the ambulance. A gel‐filled mattress decreased the transfer of mechanical vibration to the infant mannequin. Additional modifications to the isolette tray decreased vibration.

Conclusions

Relatively inexpensive modifications can be made to the isolette tray and mattress to decrease the vibration levels experienced in transport.

Introduction

Various modes of patient transport include ambulance and rotary-wing and fixed-wing aircraft. Ambulance transport induces low-frequency vibration in travel (Shenai et al., 1980). At low frequency, body resonances occur because of interaction of tissue masses with elastic structures (Goldman & Gierke, I960). It is not known where these vibration levels originate and how much vibration is transferred to an infant during transport. The effects of mechanical vibration on the infant’s biologic responses also are unknown (Shoenberger, 1975). Animal and human studies indicate that whole-body vibration could have harmful effects on premature infants with high percentages of extracellular fluid and cartilaginous tissue. This study measured the mechanical vibration experienced during ambulance transport and tested interventions that might decrease vibration.

Section snippets

Methodology

The study was conducted in three phases. In all phases, the measurement of vibration was made during land transport in a hospital-based mobile intensive-care unit (MICU). The MICU is a GMAC Diesel with a V-8 engine and air shock absorbers, Cranning Model RD 1500. The isolette used in all phases of the study was an Airshields Transport Incubator, Model TI 100, with a double wall. Vibration measurements were made with a Bruel and Kjaer type 2516 integrating vibration meter, which measures

Phase One

One-way analysis of variance (ANOVA) was used to compare acceleration levels in the following test groups:

1.
Route One (city) and Route Two (highway) mean peak acceleration levels (see Figure 2).
2.
Route One and Route Two mean Leq acceleration levels (see Figure 3).

There was a significant difference among the four sites—floor of MICU, base of isolette, tray, and forehead of mannequin. Tukey’s HSD was performed and indicated that the site of significantly higher vibration was the plastic tray inside

Discussion

The three phases of this study suggested that although mechanical vibration is an unavoidable aspect of land transport, there are interventions that can be instituted to decrease vibration transmitted to the patient. Using a thick foam pad and restraint with the isolette tray significantly decreased vibratory movement and acceleration impulses being transmitted to the mannequin. The gel-filled mattress also significantly decreased vibratory levels being transferred to the mannequin.

Although

Limitations

In this study, several limitations were identified. This study indicated a statistically significant difference (reduction) in vibration levels, but additional evaluation of their physiologic effects should be made to determine a clinical significance. Data collection was made during 5-minute segments. In an actual transport, the infant is in contact with the vibrating surface much longer. Thus, the 5-minute measurements may not truly capture the potential levels achieved in an actual

Conclusion

Nurses must be aware of the environment and external stimuli on the infant during transport. Simple, inexpensive modifications can be made to reduce the levels of mechanical vibration the infant experiences.

This study should be replicated with infants to determine the clinical effects of vibration.

References (8)

J.A. Bantle
Effects of mechanical vibrations on the growth and development of mouse embryos
Aerospace Medicine
(1971)
J.G. Clark et al.
Initial cardiovascular response to low frequency whole body vibration in humans and animals
Aerospace Medicine
(1967)
R.R. Coermann et al.
The passive dynamic mechanical properties of the human thorax‐abdomen system and of the whole body system
Aerospace Medicine
(1960)
W.N. Floyd et al.
Effect of whole body vibration on peripheral nerve conduction time in the rhesus monkey
Aerospace Medicine
(1973)

There are more references available in the full text version of this article.

Cited by (22)

Vibratory Impact of 3 Different Ambulance Suspension Systems on the Simulated Neonate and Health Care Provider During Normal Driving Conditions
2024, Air Medical Journal
Patients and health care providers experience varying degrees of vibration during interfacility ground transport. The impact of vibration on term and preterm neonates may result in physiologic instability and increased risk of intracranial hemorrhage, whereas the impact on health care providers has been shown to include an increase in perceived and physiologic stress levels and may contribute to chronic back and neck pain. This study aimed to evaluate 3 common ambulance suspension systems and the corresponding vibratory impact produced during typical interfacility driving conditions on adult caregiver and neonatal patient mannequins.
Type 3 ambulances with air, liquid, and traditional suspensions were evaluated using various driving tests to simulate typical road conditions. Vibrations were measured using triaxial accelerometers placed on the chassis, upon the head of a seated caregiver mannequin in the ambulance bench seat, and the head of a neonatal mannequin supine and secured in an isolette. Data analysis included the average vibration frequency, root mean square values, and maximum vibration amplitudes.
The results showed that the supine neonatal mannequin experienced the highest vibration frequency and amplitude in the vertical (x) direction, whereas the adult caregiver mannequin experienced higher vibration frequencies in both parallel (y) and lateral (z) directions and the highest vibration amplitude in the y direction. The liquid suspension system consistently demonstrated the lowest vibration levels in all driving conditions and directions, whereas traditional suspension had the highest values.
This study provides important insights into the vibrations incurred by simulated neonatal patients and health care providers during ambulance transport. The directional vibration frequency and amplitude differ between a neonatal mannequin and an adult mannequin when placed in typical positions with typical restraints during varied ambulance driving conditions. In all directional movements and driving conditions, a liquid suspension system decreases vibration frequency and amplitude more than air or traditional systems. The live patient and caregiver impact of these results should be further investigated.
Fifty Years of Progress in Neonatal and Maternal Transport for Specialty Care
2021, JOGNN - Journal of Obstetric, Gynecologic, and Neonatal Nursing
Citation Excerpt :
Vibration levels in transit may exceed adult limits of vibration tolerance (Bailey et al., 2019). Using a gel-filled mattress with or without a foam pad, as well as modifying the Isolette tray by inserting a foam restraint between the tray and the track on which the tray rests and putting a foam pad in the dead space beneath the tray to reduce movement of the tray, resulted in the least accentuation, or a decrease in vibration, experienced by an infant or a manikin (Gajendragadkar et al., 2000; Shenai et al., 1981; Sherwood et al., 1993). Campbell et al. (1984) compared vibration and sound levels in infants transported by ambulance, RWA, and FWA.
Specialty care for preterm and critically ill infants has evolved over many years. Neonatal intensive care nurseries were developed, and physicians and nurses learned how to provide intensive care for these infants. Neonatal and maternal (in utero) transport to tertiary centers became common in regionalized systems of care to facilitate the specialized care of high-risk neonates when childbirth occurred in settings without specialized personnel or equipment. Annually, nearly 70,000 neonatal transports occur in the United States. Although specialty care helps reduce rates of neonatal mortality, racial disparities and disparities between urban and rural areas exist. The purpose of this article is to review the progress achieved in neonatal and maternal transport over the past 50 years. The knowledge developed can be used to improve the care provided to women, their fetuses, and infants.
Whole-body vibration in neonatal transport: a review of current knowledge and future research challenges
2020, Early Human Development
Citation Excerpt :
rubber wheels [44]. A comparison of studies that used truck-based ambulances [43,54] versus van-type ambulances [29,45], demonstrated higher mechanical vibration with truck-based ambulances [31]. Blaxter et al. suggested that small changes in driving style during neonatal transports had the potential to reduce both frequency and amplitude of acceleration peaks [39].
Interfacility transport to tertiary care for high-risk neonates has become an integral part of equitable access to optimal perinatal healthcare. Excellence in clinical care requires expertise in transport medicine and the coordination of safe transport processes. However, concerns remain regarding environmental stressors involved in the transportation of sick high-risk neonates, including noise and vibration. In order to mitigate the potential deleterious effects of these physical stressors during transport, further knowledge of the burden of exposure, injury mechanisms and engineering interventions/modifications as adjuncts during transport would be beneficial. We reviewed the current literature with a focus on the contribution of new and emerging technologies in the transport environment with particular reference to whole-body vibration. This review intends to highlight what is known about vibration as a physical stressor in neonates and areas for further research; with the goal to making recommendations for minimizing these stressors during transport.
Design and experimental investigation of ultra-low frequency vibration isolation during neonatal transport
2020, Mechanical Systems and Signal Processing
Citation Excerpt :
Unfortunately, the vibration isolation performances of these two kinds of vibration isolators were not given in the patent applications [8,9]. Sherwood et al. [10] tried to improve comfort of an infant by using different types of mattresses. Gajendragadkar et al. [11] also conducted a study on finding out which kind of mattress would be the best for vibration reduction through experiments, which showed that gel-filled mattress was the most effective one.
To resolve the tough issue of ultra-low frequency vibration isolation during neonatal transport, a new incubator with quasi-zero-stiffness (QZS) isolators is proposed. In the new incubator, the infant housing unit is supported by the QZS isolators to mitigate mechanical vibration being transmitted from the ambulance floor to the infant. Each of the QZS isolators is devised by combining a pair of permanent magnet rings and a coil spring, and the design parameters are realized by the equivalent magnetic charge method. Both the prototypes of the QZS isolator and incubator are manufactured, and their vibration isolation performances are tested. The results show that the QZS isolator can fulfil vibration isolation from 2 Hz, and the incubator with four such QZS isolators is effective from 3.2 Hz under the designated payload. Most importantly, the acceleration response of the infant model in the housing unit is much lower than the base excitation, when the incubator is driven by a random base excitation with frequency bandwidth from 2 Hz to 15 Hz.
Neonatal skin care
2000, Pediatric Clinics of North America
Citation Excerpt :
For these patients, the use of sheepskin, a water mattress, or a gelled mattress or pads (e.g., Spenco pads; Gel Support, Squishon, Wedgie, Children's Medical Ventures, Inc.), in conjunction with range-of-motion exercises and regular repositioning, may help to prevent pressure sores. A gel-filled mattress is especially effective for reducing vibration during transport.152 Transparent dressings (see later section on dressings), especially over bony prominences (e.g., knees or elbows), may reduce friction injury and skin breakdown,51 and application of petrolatum or petrolatum-based ointments to the groins and thighs of VLBW infants may reduce injury caused by friction or urine.
The skin acts as an interface between the internal milieu and the environment and provides many functions essential for human survival, including:
- •
  Modulation of transepidermal water fluxes, protection from dehydration and excessive water influx, and maintenance of electrolyte homeostasis
- •
  Thermoregulation and minimization of caloric losses
- •
  Antimicrobial defense
- •
  Protection from environmental toxins
- •
  Protection from trauma
- •
  Protection from ultraviolet radiation
- •
  Tactile sensation
Of principal importance, a competent epidermal barrier is necessary at the time of birth for maintaining fluid homeostasis in the extrauterine environment. The epidermal permeability barrier resides in the stratum corneum, the outermost layer of the skin. There, it is mediated by lamellar bilayers composed of hydrophobic lipids; principally fatty acids; cholesterol; and ceramides, located in extracellular spaces of multiple layers of tightly knit, anucleate corneocytes, which are girded with a protein-rich and keratin-rich cornified cell envelope.⁵⁶ The barrier typically forms in utero during the third trimester. Developmental immaturity of the permeability barrier may include:
- •
  Structural immaturity
  Stratum corneum and epidermis are thinner than in term infants.
  Anchoring fibrils, anchoring filaments, and hemidesmosomes are fewer and smaller than in term infants, leading to decreased anchoring of the epidermis and increased susceptibility to shear forces.
- •
  Stratum corneum epidermal permeability barrier is underdeveloped, leading to increased transepidermal water loss, loss of heat, increased caloric demands, increased potential for absorption of environmental toxins, and compromised antimicrobial defense.
- •
  Expression of cationic antimicrobial peptides may be developmentally decreased.
- •
  Antibacterial acid mantle forms more slowly in neonates weighing less than 1 kg than in larger, more mature neonates.
- •
  Formation of a protective layer of vernix is underdeveloped.
- •
  Decreased numbers of melanocytes with immature melanosomes leads to increased susceptibility to ultraviolet light–induced damage.
- •
  A reduced subcutaneous fat supply limits thermoregulatory capabilities and buffering capacity against redistribution of fat-soluble drugs.
Developmental immaturity and a large surface area-to-body mass ratio can cause transepidermal water loss (TEWL), which correlates with epidermal barrier function,⁶⁸ to be 10-fold to 15-fold greater in premature infants of 25 weeks' gestation compared with full-term infants.⁷⁰ This may result in fluid losses of as much as 30% of total body weight in 24 hours and may be associated with:
- •
  Significant morbidity caused by dehydration and hypotension, increasing the risk for intraventricular hemorrhage and, possibly, necrotizing enterocolitis
- •
  Electrolyte imbalance, especially hyperosmolar hypernatremia, which also may place neonates at increased risk for intraventricular hemorrhage
- •
  Thermal instability
- •
  Increased caloric demands because skin evaporative losses (580 calories/mL) may comprise as much as 20% of the total energy expenditure of preterm infants born at less than 30 weeks' gestational age
Furthermore, rehydration of preterm infants may be fraught with difficulty and exacerbate or induce patent ductus arteriosus, congestive heart failure, pulmonary edema, and possibly necrotizing enterocolitis.
Another critical function of the skin is antimicrobial defenses, which include:
- •
  Stratum corneum: xeric environment, acidic pH (i.e., “acid mantle”), antimicrobial lipids (e.g., oleic acid, sphingosine, sphinganine, hydroxysphinganine; possibly serine protease activity of cholesterol sulfate), continual shedding of corneocytes
- •
  Cationic antimicrobial peptides: skin-derived antileukoprotease (elafin), secretory leukocyte protease inhibitor (SLPI; antileukoprotease), human β-defensin-2, LL-37
- •
  Cytokines: interleukin (IL)-1α, IL-1β, tumor necrosis factor-α, IL-10, and IL-12
- •
  Granzyme B
- •
  Fas ligand
- •
  Nitric oxide
- •
  Resident cutaneous flora (e.g., bacterial interference or bacteriocins) (not part of the innate immune system, but defense is intrinsic to the skin)
A developmentally mature and intact stratum corneum seems to effectively prevent infection of the skin and impedes microbial invasion mechanically and through its acidic pH; xeric environment; and the release of antibacterial products, including cytokines, lipid breakdown products and cationic antimicrobial peptides.48, 121 Neonates, especially preterm infants, are at high risk for infection, however, because of epidermal barrier immaturity; developmental defects in systemic immune function; and, possibly, disordered cutaneous immunoregulatory function in association with barrier perturbation or decreased cationic antimicrobial peptide expression.126, 127 As a result, infectious diseases and prematurity, together with birth asphyxia, are the major causes of neonatal deaths worldwide. Approximately one fourth of all very low birth weight (VLBW) infants weighing less than 1.5 kg in the United States who survive beyond the third day of life have at least one episode of sepsis.¹⁶⁵ In developing countries, the prevalence of sepsis in premature infants is estimated at 30% to 60%, and the mortality rate is 40% to 70%; septicemia is the most prevalent cause of death, accounting for as much as 50% of neonatal mortality in premature infants.13, 164 Globally, an estimated 350,000 of neonates die each year because of septicemia and meningitis¹⁶⁴; approximately half of these deaths occur in the first week of life, when epidermal barrier function is most highly compromised.
Postnatal age and gestational age are important considerations in assessing skin maturity and in determining skin-care practices because exposure of premature skin following birth to the dry, extrauterine environment accelerates development of an effective epidermal barrier.71, 74, 183 Barrier maturation following premature birth, however, typically requires approximately 2 to 4 weeks and may require as long as 8 weeks in extremely premature infants.74, 88 This suggests that, as more preterm infants survive at earlier gestational ages that approach the limits for interfollicular cornification and stratum corneum maturation at 22 to 24 weeks' gestational age, the stratum corneum responds more slowly to maturational signals expressed after birth.73, 182 During the neonatal period, although barrier function is developing, premature infants suffer significant morbidity and mortality, especially during the first week of life, when approximately two thirds of neonatal deaths occur.⁹⁰
The importance of neonatal skin care is exemplified by survey results suggesting that nearly 80% of newborns develop a skin problem (i.e., “rash”) during the first month of life.⁴² But little information is available on which a rational approach to skin care in neonates may be based, and few instructions or recommendations for neonatal skin care are available in the literature.* This article reviews fundamental care and hygiene of neonatal skin, with particular reference to preterm infants born at less than 33 weeks' gestational age and hospitalized neonates who require intensive care, in whom these activities are of vital importance. Strategies for optimizing epidermal barrier integrity, including bathing and emolliation practices, preventing and managing infections and skin injury, and minimizing TEWL and heat or percutaneous absorption of toxins, are emphasized.
Simulating whole-body vibration for neonatal patients on a tire-coupled road simulator
2024, Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine

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Clinical StudiesMechanical Vibration in Ambulance Transport

Objective

Design

Participants

Main Outcome Measure

Results

Conclusions

Introduction

Section snippets

Methodology

Phase One

Discussion

Limitations

Conclusion

Effects of mechanical vibrations on the growth and development of mouse embryos

Aerospace Medicine

Initial cardiovascular response to low frequency whole body vibration in humans and animals

Aerospace Medicine

The passive dynamic mechanical properties of the human thorax‐abdomen system and of the whole body system

Aerospace Medicine

Effect of whole body vibration on peripheral nerve conduction time in the rhesus monkey

Aerospace Medicine

Clinical Studies
Mechanical Vibration in Ambulance Transport