1
|
Re R, Lassola S, De Rosa S, Bellani G. Humidification during Invasive and Non-Invasive Ventilation: A Starting Tool Kit for Correct Setting. Med Sci (Basel) 2024; 12:26. [PMID: 38804382 PMCID: PMC11130810 DOI: 10.3390/medsci12020026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/22/2024] [Accepted: 05/10/2024] [Indexed: 05/29/2024] Open
Abstract
The humidification process of medical gases plays a crucial role in both invasive and non-invasive ventilation, aiming to mitigate the complications arising from bronchial dryness. While passive humidification systems (HME) and active humidification systems are prevalent in routine clinical practice, there is a pressing need for further evaluation of their significance. Additionally, there is often an incomplete understanding of the operational mechanisms of these devices. The current review explores the historical evolution of gas conditioning in clinical practice, from early prototypes to contemporary active and passive humidification systems. It also discusses the physiological principles underlying humidity regulation and provides practical guidance for optimizing humidification parameters in both invasive and non-invasive ventilation modalities. The aim of this review is to elucidate the intricate interplay between temperature, humidity, and patient comfort, emphasizing the importance of individualized approaches to gas conditioning.
Collapse
Affiliation(s)
- Riccardo Re
- Anesthesia and Intensive Care 1, Santa Chiara Hospital, APSS, Largo Medaglie d’Oro 9, 38112 Trento, Italy;
| | - Sergio Lassola
- Anesthesia and Intensive Care 1, Santa Chiara Hospital, APSS, Largo Medaglie d’Oro 9, 38112 Trento, Italy;
| | - Silvia De Rosa
- Centre for Medical Sciences—CISMed, University of Trento, Via S. Maria Maddalena 1, 38122 Trento, Italy; (S.D.R.); (G.B.)
| | - Giacomo Bellani
- Centre for Medical Sciences—CISMed, University of Trento, Via S. Maria Maddalena 1, 38122 Trento, Italy; (S.D.R.); (G.B.)
| |
Collapse
|
2
|
Jia YG, Li TR, Lau RWT, Lian SB, Zhou JY, Liu JL, Pan XZ. Can humidifier reservoir bacteria colonize the circuit during mechanical ventilation: An in vitro study. Nurs Crit Care 2024. [PMID: 38358027 DOI: 10.1111/nicc.13046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 01/28/2024] [Accepted: 01/30/2024] [Indexed: 02/16/2024]
Abstract
BACKGROUND Although the circuit condensate, an ideal bacterial reservoir during mechanical ventilation, may flow into the humidifier reservoir, no studies have investigated if humidifier reservoir colonized bacteria colonize other circuit locations with airflow. AIMS We aimed to prove whether the humidifier reservoir colonized bacteria colonize other circuit locations with airflow and provide some advice on the disposal of condensate in the clinical setting. STUDY DESIGN An in vitro experiment was conducted. Mechanical ventilation simulators (n = 90) were divided into sterile water group (n = 30) and broth group (n = 60). In the sterile water group, sterile water was used for humidification, either Acinetobacter baumannii or Pseudomonas aeruginosa were inoculated to humidifier water in the humidifier reservoir, each accounted for 50% of the simulators. The broth group was performed the same as the sterile water group except for the addition of broth into the humidified water. After 24, 72, and 168 h of continuous ventilation, the humidifier water and different locations of the circuits were sampled for bacterial culture. RESULTS All bacterial culture results of the sterile water group were negative. Bacteria in the humidifier water continued to proliferate in the broth group. With prolonged ventilation, the bacteria at the humidifier reservoir outlet increased. The bacteria at the humidifier reservoir outlet were much more in the Pseudomonas aeruginosa subgroup than in the Acinetobacter baumannii subgroup and the difference was statistically significant (p < .05). During continuous ventilation, no bacterial growth occurred at 10 cm from the humidifier reservoir outlet and the Y-piece of the ventilator circuits. CONCLUSIONS Sterile water in the humidifier reservoir was not conducive to bacterial growth. Even if bacteria grew in the humidifier reservoir and could reach the humidifier reservoir outlet, colonization of further circuit locations with the airflow was unlikely. During a certain mechanical ventilation time, the amount of bacteria reaching the outlet of the humidifier reservoir varied due to different mobility of bacteria. RELEVANCE TO CLINICAL PRACTICE In a clinical setting, nurses should not worry about a small amount of condensate backflow into the humidifier reservoir. Draining condensate into the humidifier reservoir can be used as a low risk and convenient method in clinical practice.
Collapse
Affiliation(s)
- Yong-Gang Jia
- Division of Cardiovascular Intensive Care, Cardiac and Vascular Center, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Tian-Ran Li
- Shenzhen Municipal Healthcare Security Bureau Longhua Sub-bureau, Shenzhen, China
| | - Ricky Wing Tong Lau
- Division of Microbiology, Department of Infectious Diseases and Microbiology, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Su-Bing Lian
- Division of Cardiovascular Intensive Care, Cardiac and Vascular Center, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Jin-Yang Zhou
- Division of Cardiovascular Surgery, Cardiac and Vascular Center, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Jie-Ling Liu
- Division of Infection Control, Department of Infectious Disease Medicine, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Xia-Zhen Pan
- Division of Cardiovascular Intensive Care, Cardiac and Vascular Center, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| |
Collapse
|
3
|
High-frequency ventilation in preterm infants and neonates. Pediatr Res 2022:10.1038/s41390-021-01639-8. [PMID: 35136198 DOI: 10.1038/s41390-021-01639-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 06/20/2021] [Accepted: 06/21/2021] [Indexed: 11/08/2022]
Abstract
High-frequency ventilation (HFV) has been used as a respiratory support mode for neonates for over 30 years. HFV is characterized by delivering tidal volumes close to or less than the anatomical dead space. Both animal and clinical studies have shown that HFV can effectively restore lung function, and potentially limit ventilator-induced lung injury, which is considered an important risk factor for developing bronchopulmonary dysplasia (BPD). Knowledge of how HFV works, how it influences cardiorespiratory physiology, and how to apply it in daily clinical practice has proven to be essential for its optimal and safe use. We will present important aspects of gas exchange, lung-protective concepts, clinical use, and possible adverse effects of HFV. We also discuss the study results on the use of HFV in respiratory distress syndrome in preterm infants and respiratory failure in term neonates. IMPACT: Knowledge of how HFV works, how it influences cardiorespiratory physiology, and how to apply it in daily clinical practice has proven to be essential for its optimal and safe use. Therefore, we present important aspects of gas exchange, lung-protective concepts, clinical use, and possible adverse effects of HFV. The use of HFV in daily clinical practice in lung recruitment, determination of the optimal continuous distending pressure and frequency, and typical side effects of HFV are discussed. We also present study results on the use of HFV in respiratory distress syndrome in preterm infants and respiratory failure in term neonates.
Collapse
|
4
|
Ralphe JL, Silva SG, Dail RB, Brandon DH. The Association Between Very Premature Infant Body Temperatures Over Time and Respiratory Care. Biol Res Nurs 2021; 23:331-340. [PMID: 33124439 PMCID: PMC8755953 DOI: 10.1177/1099800420969865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Due to global immaturity, very low birthweight (VLBW) infants (<1,500 g) require auxiliary thermal and respiratory care. However, the impact of respiratory care on infant thermal stability remains unclear. AIMS Examine the association between VLBW infant body temperatures over time and respiratory support type (mechanical ventilation (MV), continuous positive airway pressure (CPAP), room air (RA)), respiratory care interventions, and nursing care. DESIGN Exploratory, longitudinal, and correlational design. SUBJECTS 12 infants <29 weeks' gestation (median = 27.1, 25.9-27.9) and <1,200 g (median = 865 g, 660-1,050 g). MEASUREMENTS Minute-to-minute body temperatures and continuous video data were collected over the first 5 days of life. Video data was coded with Noldus Observer®XT software. Respiratory support was retrieved from the electronic health record. Hierarchical multi-level, mixed-effects models for intensive longitudinal data examined the associations. RESULTS Body temperatures were associated with respiratory support type, respiratory care, and care events (all p < .0001). Pairwise comparison found significant differences in body temperatures between all respiratory support types (all p < .0001). The covariate-adjusted risk of hypothermia (<36.5 °C) was significantly greater during MV vs. RA (aOR = 2.6); CPAP vs. MV (aOR = 1.2); CPAP vs RA (aOR = 3.1); respiratory care vs. other types of care (aOR = 1.5); care event vs. closed portholes (aOR = 2.6). CONCLUSION Our results found an association between VLBW infant thermal instability and respiratory support type, respiratory care, and care events. Larger studies with advanced longitudinal analysis are needed to assess the causal impact of these interventions on infant temperatures over time, as well as the implications of longitudinal thermal instability on infant outcomes.
Collapse
Affiliation(s)
- Jane L. Ralphe
- School of Nursing, University of Wisconsin–Madison, WI, USA
| | - Susan G. Silva
- School of Nursing, Duke University, Durham, NC, USA
- School of Medicine, Duke University, Durham, NC, USA
| | - Robin B. Dail
- College of Nursing, University of South Carolina, Columbia, SC, USA
| | - Debra H. Brandon
- School of Nursing, Duke University, Durham, NC, USA
- School of Medicine, Duke University, Durham, NC, USA
| |
Collapse
|
5
|
Ruppert JA, McNinch NL, Volsko TA. An evaluation of temperature stability and resistance in neonatal ventilator circuits. ACTA ACUST UNITED AC 2021; 57:8-13. [PMID: 33532559 PMCID: PMC7845534 DOI: 10.29390/cjrt-2020-042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Gas conditioning minimizes complications associated with invasive ventilation of neonates. Poorly conditioned gas contributes to humidity deficit, facilitates condensate pools, and contributes to safety events. The specific aim was to objectively quantify the temperature drop across the unheated portion of a neonatal circuit and the impact condensation has to resistance to flow in the ventilator circuit. Methods Ventilator circuits and filters were obtained, assembled according to manufacturer recommendations, and operational verification procedures were performed prior to data collection. A neonatal test lung was connected to each Servo-I ventilator with the following settings: pressure control IMV mode; inspiratory pressure: 14 cm H2O to achieve an exhaled tidal volume of 6.0 mL; PEEP: 5 cm H2O; pressure support: 5 cm H2O, FIO2: 0.21; set frequency 40/min; and inspiratory time: 0.4 s. The Fisher and Paykel MR850 and ChonchaTherm Neptune heaters were set at a temperature of 40°C. To evaluate both systems under similar conditions, the ChonchaTherm Neptune heater humidity control was set to midline. Heaters were turned on simultaneously and given 1 h to equilibrate. Readings for room temperature, airway temperature at the patient connection, airway resistance, exhaled tidal volume, and direct observation of circuit condensation and (or) pooling were recorded hourly for a 48-h period. Summary statistics were calculated for the variables of interest. Results Mean (±SD) air temperature was 26.3°C (±1.4) for the Fisher & Paykel MR850 system and 26.2°C (±1.5), for the ChonchaTherm Neptune system. Mean (±SD) airway resistance was 229.3 cm H2O/L/s (±81.0) for the Fisher & Paykel system and 196.2 cm H2O/L/s (±39.4) for the ChonchaTherm Neptune system. Mean (±SD) tidal volume for the Fisher & Paykel MR850 system was 6.5 mL (±0.4), and for the ChonchaTherm Neptune system was 7.2 mL (±0.6). Conclusion Circuit condensate increased tidal volume delivery and airway resistance. Temperature at the patient connection was lower than the temperature monitored by the system 12 inches distally, which can negatively impact gas conditioning.
Collapse
Affiliation(s)
- Jennifer A Ruppert
- Department of Respiratory Care, Akron Children's Hospital, Akron, OH, USA
| | - Neil L McNinch
- Rebecca D. Considine Research Institute, Akron Children's Hospital, Akron, OH, USA
| | - Teresa A Volsko
- Department of Nursing Administration, Akron Children's Hospital, Akron, OH, USA
| |
Collapse
|
6
|
Temperature and Humidity Associated With Artificial Ventilation in the Premature Infant: An Integrative Review of the Literature. Adv Neonatal Care 2018; 18:366-377. [PMID: 29933338 DOI: 10.1097/anc.0000000000000519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
BACKGROUND Approximately half of the 55,000 very low birth-weight infants (<1500 g) born in the United States each year develop bronchopulmonary dysplasia (BPD). Many etiologies have been associated with the development of BPD, including aberrant temperature/humidity levels of artificial ventilation. PURPOSE The purpose of this literature review is to explore what is known regarding inspired air temperature/humidity levels from artificial ventilation in very premature infants, focusing on what levels these infants actually receive, and what factors impact these levels. METHODS/SEARCH STRATEGY PubMed, CINAHL, Scopus, and Web of Science were searched. Of the 830 articles retrieved, 23 were synthesized for study purpose, sample/study design, and temperature/humidity findings. FINDINGS/RESULTS Heating and humidification practices studied in neonatal ventilation did not maintain recommended levels. In addition, human neonatal studies and noninvasive neonatal ventilation research were limited. Furthermore, ventilation settings, environmental temperatures, and mouth position (in noninvasive ventilation) were found to impact temperature/humidity levels. IMPLICATIONS FOR PRACTICE Environmental temperatures and ventilatory settings merit consideration during artificial ventilation. In addition, aberrant temperature/humidity levels may impact infant body temperature stability; thus, employing measures to ensure adequate thermoregulation while receiving artificial ventilation must be a priority. IMPLICATIONS FOR RESEARCH This review underscores the need for further research into current warming and humidification techniques for invasive and noninvasive neonatal ventilation. A focus on human studies and the impact of aberrant levels on infant body temperature are needed. Future research may provide management options for achieving and maintaining target temperature/humidity parameters, thus preventing the aberrant levels associated with BPD.
Collapse
|
7
|
McGrory L, Owen LS, Thio M, Dawson JA, Rafferty AR, Malhotra A, Davis PG, Kamlin COF. A Randomized Trial of Conditioned or Unconditioned Gases for Stabilizing Preterm Infants at Birth. J Pediatr 2018; 193:47-53. [PMID: 29106924 DOI: 10.1016/j.jpeds.2017.09.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 08/07/2017] [Accepted: 09/06/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVE To determine whether the use of heated-humidified gases for respiratory support during the stabilization of infants <30 weeks of gestational age (GA) in the delivery room reduces rates of hypothermia on admission to the neonatal intensive care unit (NICU). STUDY DESIGN A multicenter, unblinded, randomized trial was conducted in Melbourne, Australia, between February 2013 and June 2015. Infants <30 weeks of GA were randomly assigned to receive either heated-humidified gases or unconditioned gases during stabilization in the delivery room and during transport to NICU. Infants born to mothers with pyrexia >38°C were excluded. Primary outcome was rate of hypothermia on NICU admission (rectal temperature <36.5°C). RESULTS A total of 273 infants were enrolled. Fewer infants in the heated-humidified group were hypothermic on admission to NICU (36/132 [27%]) compared with controls (61/141 [43%], P < .01). There was no difference in rates of hyperthermia (>37.5°C); 20% (27/132) in the heated-humidified group compared with 16% (22/141) in the controls (P = .30). There were no differences in mortality or respiratory outcomes. CONCLUSIONS The use of heated-humidified gases in the delivery room significantly reduces hypothermia on admission to NICU in preterm infants, without increased risk of hyperthermia. CLINICAL TRIAL REGISTRATION Australian and New Zealand Clinical Trials Register (www.anzctr.org.au) ACTRN12613000093785.
Collapse
Affiliation(s)
- Lorraine McGrory
- Department of Newborn Research, The Royal Women's Hospital, Melbourne, Australia; Department of Child Health, The University of Dundee, Dundee, United Kingdom.
| | - Louise S Owen
- Department of Newborn Research, The Royal Women's Hospital, Melbourne, Australia; The Murdoch Childrens Research Institute, Melbourne, Australia; Department of Obstetrics and Gynaecology, The University of Melbourne, Melbourne, Australia
| | - Marta Thio
- Department of Newborn Research, The Royal Women's Hospital, Melbourne, Australia; The Murdoch Childrens Research Institute, Melbourne, Australia; Department of Obstetrics and Gynaecology, The University of Melbourne, Melbourne, Australia
| | - Jennifer A Dawson
- Department of Newborn Research, The Royal Women's Hospital, Melbourne, Australia; The Murdoch Childrens Research Institute, Melbourne, Australia; Department of Obstetrics and Gynaecology, The University of Melbourne, Melbourne, Australia
| | - Anthony R Rafferty
- Department of Newborn Research, The Royal Women's Hospital, Melbourne, Australia
| | - Atul Malhotra
- Monash Newborn, Monash Children's Hospital, Melbourne, Australia; Department of Pediatrics, Monash University, Melbourne, Australia
| | - Peter G Davis
- Department of Newborn Research, The Royal Women's Hospital, Melbourne, Australia; The Murdoch Childrens Research Institute, Melbourne, Australia; Department of Obstetrics and Gynaecology, The University of Melbourne, Melbourne, Australia
| | - C Omar F Kamlin
- Department of Newborn Research, The Royal Women's Hospital, Melbourne, Australia; The Murdoch Childrens Research Institute, Melbourne, Australia; Department of Obstetrics and Gynaecology, The University of Melbourne, Melbourne, Australia
| |
Collapse
|
8
|
Ullrich TL, Czernik C, Bührer C, Schmalisch G, Fischer HS. Nasal high-frequency oscillatory ventilation impairs heated humidification: A neonatal bench study. Pediatr Pulmonol 2017; 52:1455-1460. [PMID: 28881101 DOI: 10.1002/ppul.23824] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 08/13/2017] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Nasal high-frequency oscillatory ventilation (nHFOV) is a novel mode of non-invasive ventilation used in neonates. However, upper airway obstructions due to viscous secretions have been described as specific adverse effects. We hypothesized that high-frequency oscillations reduce air humidity in the oropharynx, resulting in upper airway desiccation. Therefore, we aimed to investigate the effects of nHFOV ventilatory settings on oropharyngeal gas conditions. METHODS NHFOV or nasal continuous positive airway pressure (nCPAP) was applied, along with heated humidification, to a previously established neonatal bench model that simulates oropharyngeal gas conditions during spontaneous breathing through an open mouth. A digital thermo-hygro sensor measured oropharyngeal temperature (T) and humidity at various nHFOV frequencies (7, 10, 13 Hz), amplitudes (10, 20, 30 cmH2 O), and inspiratory-to-expiratory (I:E) ratios (25:75, 33:66, 50:50), and also during nCPAP. RESULTS Relative humidity was always >99%, but nHFOV resulted in lower mean T and absolute humidity (AH) in comparison to nCPAP (P < 0.001). Specifically, decreasing the nHFOV frequency and increasing nHFOV amplitude caused a decline in T and AH (P < 0.001). Mean T and AH were highest during nCPAP (T 34.8 ± 0.6°C, AH 39.3 ± 1.3 g · m-3 ) and lowest during nHFOV at a frequency of 7 Hz and an amplitude of 30 cmH2 O (T 32.4 ± 0.3°C, AH 34.7 ± 0.5 g · m-3 ). Increasing the I:E ratio also reduced T and AH (P = 0.03). CONCLUSION Intensified nHFOV settings with low frequencies, high amplitudes, and high I:E ratios may place infants at an increased risk of upper airway desiccation. Future studies should investigate strategies to optimize heated humidification during nHFOV.
Collapse
Affiliation(s)
- Tim L Ullrich
- Department of Neonatology, Charité University Medical Center, Berlin, Germany
| | - Christoph Czernik
- Department of Neonatology, Charité University Medical Center, Berlin, Germany
| | - Christoph Bührer
- Department of Neonatology, Charité University Medical Center, Berlin, Germany
| | - Gerd Schmalisch
- Department of Neonatology, Charité University Medical Center, Berlin, Germany
| | - Hendrik S Fischer
- Department of Neonatology, Charité University Medical Center, Berlin, Germany
| |
Collapse
|
9
|
Doctor TN, Foster JP, Stewart A, Tan K, Todd DA, McGrory L. Heated and humidified inspired gas through heated humidifiers in comparison to non-heated and non-humidified gas in hospitalised neonates receiving respiratory support. Hippokratia 2017. [DOI: 10.1002/14651858.cd012549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Tejas N Doctor
- Monash Medical Centre; Monash Newborn; 246 Clayton Road Clayton Victoria Australia 3168
| | - Jann P Foster
- Western Sydney University; School of Nursing and Midwifery; Penrith DC Australia
- University of Sydney; Sydney Nursing School/Central Clinical School, Discipline of Obstetrics, Gynaecology and Neonatology; Sydney Australia
- Ingham Research Institute; Liverpool NSW Australia
| | - Alice Stewart
- Monash Medical Centre; Monash Newborn; 246 Clayton Road Clayton Victoria Australia 3168
| | - Kenneth Tan
- Monash University; Department of Paediatrics; 246 Clayton Road Clayton Melbourne Victoria Australia VIC 3168
| | - David A Todd
- The Canberra Hospital; Neonatal Unit; Centre for Newborn Care PO Box 11, Woden Canberra ACT Australia 2606
| | - Lorraine McGrory
- The Royal Women's Hospital; Neonatal Services; Parkville Victoria Australia
| |
Collapse
|
10
|
Influence of mouth opening on oropharyngeal humidification and temperature in a bench model of neonatal continuous positive airway pressure. Med Eng Phys 2016; 40:87-94. [PMID: 28043780 DOI: 10.1016/j.medengphy.2016.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 08/07/2016] [Accepted: 12/20/2016] [Indexed: 01/02/2023]
Abstract
Clinical studies show that non-invasive respiratory support by continuous positive airway pressure (CPAP) affects gas conditioning in the upper airways, especially in the presence of mouth leaks. Using a new bench model of neonatal CPAP, we investigated the influence of mouth opening on oropharyngeal temperature and humidity. The model features the insertion of a heated humidifier between an active model lung and an oropharyngeal head model to simulate the recurrent expiration of heated, humidified air. During unsupported breathing, physiological temperature and humidity were attained inside the model oropharynx, and mouth opening had no significant effect on oropharyngeal temperature and humidity. During binasal CPAP, the impact of mouth opening was investigated using three different scenarios: no conditioning in the CPAP circuit, heating only, and heated humidification. Mouth opening had a strong negative impact on oropharyngeal humidification in all tested scenarios, but heated humidification in the CPAP circuit maintained clinically acceptable humidity levels regardless of closed or open mouths. The model can be used to test new equipment for use with CPAP, and to investigate the effects of other methods of non-invasive respiratory support on gas conditioning in the presence of leaks.
Collapse
|
11
|
Meyer MP, Hou D, Ishrar NN, Dito I, te Pas AB. Initial respiratory support with cold, dry gas versus heated humidified gas and admission temperature of preterm infants. J Pediatr 2015; 166:245-50.e1. [PMID: 25449225 DOI: 10.1016/j.jpeds.2014.09.049] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 08/18/2014] [Accepted: 09/25/2014] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To assess whether the addition of heated humidified gas (HHG) at delivery and until neonatal unit arrival improved admission temperatures of preterm infants. STUDY DESIGN This multicenter, randomized controlled trial was performed in New Zealand and The Netherlands. Infants <32 weeks' gestation who required respiratory support after delivery were randomized to either cold, dry gas or HHG from birth. Standard measures to prevent hypothermia included heated delivery rooms, the use of radiant warmers, body wrap, and head covering. The primary outcome was axillary temperature in the normothermic (36.5-37.5°C) range on admission to a neonatal intensive care unit. Secondary outcomes were measures of respiratory support and neonatal morbidities. The effect of humidification was analyzed by the use of logistic regression. RESULTS Of 203 randomized infants, 100 received HHG (humidifier set to 37°C) and 103 received cold, dry gas. In the HHG group, 69 (69%) were normothermic compared with 57 (55%) in the cold, dry gas group (unadjusted OR 1.8, 95% CI 1.01-3.19). A greater number of infants <28 weeks were normothermic on admission in the HHG group (24/35; ie, 69%) compared with the cold, dry gas group (16/38; ie, 42%; P = .03). In addition, 2 (2%) infants in the HHG group had admission temperatures <35.5°C compared with 12 (12%) in the cold, dry gas group (P = .007). Respiratory and short-term outcomes were not different. CONCLUSION Adding HHG during respiratory support in preterm infants from birth increased the incidence of normothermia at admission.
Collapse
Affiliation(s)
- Michael P Meyer
- KidzFirst Neonatal Unit, Middlemore Hospital, Auckland, New Zealand; Department of Pediatrics: Child and Youth Health, University of Auckland, Auckland, New Zealand.
| | - David Hou
- KidzFirst Neonatal Unit, Middlemore Hospital, Auckland, New Zealand; Department of Pediatrics: Child and Youth Health, University of Auckland, Auckland, New Zealand
| | - Nazmul N Ishrar
- KidzFirst Neonatal Unit, Middlemore Hospital, Auckland, New Zealand
| | - Ingrid Dito
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Arjan B te Pas
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
| |
Collapse
|
12
|
Nagaya K, Tsuchida E, Nohara F, Okamoto T, Azuma H. The temperature change in an endotracheal tube during high frequency ventilation using an artificial neonatal lung model with Babylog® 8000 plus. Pediatr Pulmonol 2015; 50:173-8. [PMID: 24574439 DOI: 10.1002/ppul.22973] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Accepted: 11/19/2013] [Indexed: 11/06/2022]
Abstract
OBJECTIVE There is little available data on airway humidity during high-frequency ventilation (HFV). The purpose of this study is to evaluate the temperature drop in an endotracheal tube (ETT) during HFV. METHODS We examined the airway temperature in a neonatal HFV system using Babylog® 8000 plus. We measured the temperature change of inspired gases in the ETT under various oscillatory frequencies and oscillatory volumes with a fixed base flow. The temperatures in the ETT during HFV were compared with the temperatures during conventional intermittent positive pressure ventilation (IPPV). RESULTS As the oscillatory frequency was increased and the oscillatory volume (VThf) decreased, the difference in temperature between the Y piece and the inlet of an artificial lung in the ETT (ETT outside of body) increased. However, as the oscillatory frequency increased, there was no difference in the ETT temperature under constant oscillatory volume. In contrast, as the oscillatory volume was decreased, the difference in temperature in the ETT was greater under constant oscillatory frequency. Moreover, the temperature drop in the ETT with HFV was lower than that in the IPPV temperature with a similar respiratory volume. CONCLUSIONS The temperature change in the ETT was not dependent on the oscillatory frequency when the oscillatory volume was fixed; however, the temperature was dependent on the oscillatory volume when the oscillatory frequency was fixed.
Collapse
Affiliation(s)
- Ken Nagaya
- The Center for Maternity and Infant Care, Asahikawa Medical University, Hokkaido, Japan
| | | | | | | | | |
Collapse
|
13
|
Naylor JF. Otoscope fogging: examination finding for perforated tympanic membrane. BMJ Case Rep 2014; 2014:bcr-2013-200707. [PMID: 24879720 DOI: 10.1136/bcr-2013-200707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The author reports a recently recognised physical examination finding, otoscope fogging, for perforated tympanic membrane. Otoscope fogging is defined as condensation forming in the view field of the otoscope while inspecting the ear. In the setting of occult perforation secondary to the inability to visualise the entire tympanic membrane, otoscope fogging may provide the clinician with valuable information since medical management may differ if perforation is present.
Collapse
Affiliation(s)
- Jason F Naylor
- Department of Primary Care, Irwin Army Community Hospital, Fort Riley, Kansas, USA
| |
Collapse
|
14
|
Owen LS, Dawson JA, Middleburgh R, Buttner S, McGrory L, Davis PG. Feasibility and practical considerations for heating and humidifying gases during newborn stabilisation: an in vitro model. Neonatology 2014; 106:156-62. [PMID: 24993671 DOI: 10.1159/000363126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 04/23/2014] [Indexed: 11/19/2022]
Abstract
BACKGROUND Gases for respiratory support at birth are typically 'cold and dry', which may increase the risk of hypothermia and lung injury. OBJECTIVES To determine the feasibility of using heated humidification from birth. METHOD A humidifier targeting 37°C, a manual-fill chamber and a Neopuff Infant T-piece resuscitator and circuit were attached to a face mask and a manikin. Recordings using 20 ml H2O for humidification and a flow of 10 l/min were undertaken. Temperature and relative humidity (RH) were recorded. Additional recordings were made, each with one alteration to baseline (50 ml H2O for humidification, auto-fill chamber, a flow of 8 l/min, addition of circuit extension piece, warmed humidification H2O, increased ambient temperature and targeting 31°C). The duration of heated humidification and the response to disconnecting the power were investigated. RESULTS The baseline circuit achieved 95% RH and 31°C in 3 min, >99% RH in 7 min and ≥35°C in 9 min. No circuit alterations resulted in faster gas conditioning. The extended length circuit and targeting 31°C reduced the maximum temperature achieved. A flow of 8 l/min resulted in slower heating and humidification. The baseline circuit delivered heated humidification for 39 min. Without power, the temperature and humidity fell below international standards in 3 min. CONCLUSION Rapid gas conditioning for newborn stabilisation is feasible using the experimental set-up, ≥20 ml H2O and a flow of 10 l/min. The circuit could be used immediately once switched on. Without power, conditioning is quickly lost. Investigation of the clinical effects of gas conditioning is warranted.
Collapse
Affiliation(s)
- Louise S Owen
- The Royal Women's Hospital, Melbourne, Vic., Australia
| | | | | | | | | | | |
Collapse
|
15
|
Effect of flow rate, humidifier dome and water volume on maximising heated, humidified gas use for neonatal resuscitation. Resuscitation 2013; 84:1428-32. [DOI: 10.1016/j.resuscitation.2013.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 04/05/2013] [Accepted: 04/06/2013] [Indexed: 11/20/2022]
|
16
|
Schena E, De Paolis E, Silvestri S. Gas pre-warming for improving performances of heated humidifiers in neonatal ventilation. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:1205-8. [PMID: 22254532 DOI: 10.1109/iembs.2011.6090283] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Adequate temperature and humidification of gas delivered must be performed during long term neonatal ventilation to avoid potential adverse health effects. Literature shows that performances of heated humidifiers are, at least in some cases, quite poor. In this study, a novel approach to gas conditioning, consisting of gas warming upstream the humidification chamber, is presented. Gas pre-warming, in combination with a control strategy based on a mathematical model taking into account a number of parameters, allows to significantly improve the heated humidifier performances. The theoretical model has been validated and experimental trials have been carried out in the whole volumetric flow-rate (Q) range of neonatal ventilation (lower than 10 L · min(-1)). Experimental results (temperature values ranging from 36 °C to 38 °C and relative humidity values from 90 % to 98 % in the whole range of Q) show values very close to the ideal thermo-hygrometric conditions. The proposed solution allows to avoid vapor condensation at low flow rates and decrease of relative humidity at high flow rates.
Collapse
Affiliation(s)
- E Schena
- Unit of Measurements and Biomedical Instrumentation, Center for Integrated Research, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21-00128- Rome, Italy
| | | | | |
Collapse
|
17
|
Shearman AD, Hou D, Dunster KR, Jardine L. Heating of gases during neonatal resuscitation: a bench study. Resuscitation 2011; 83:369-73. [PMID: 21958926 DOI: 10.1016/j.resuscitation.2011.08.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 07/11/2011] [Accepted: 08/22/2011] [Indexed: 11/16/2022]
Abstract
AIM Standard practice within the neonatal unit is to use heated humidified gas as it decreases respiratory complications in neonates requiring respiratory support. Using cold unhumidified gases during resuscitation could potentially cool the baby as well as exacerbate potential lung injury. We aimed to study the temperature and humidity aspects of using heated, humidified gas for neonatal resuscitation. METHODS A heated patient circuit was connected to a T-piece resuscitator via a humidifier. An oxygen flowmeter was set at 10 L/min. Temperature recordings at the humidifier chamber (T1), distal temperature probe (T2) and T-piece (T3) were taken over 20 min at 30s intervals. A humidity sensor was placed at T3. RESULTS Target temperatures were not reached. Time to 36°C (mean (sd)): T1 11.1 min (1.71); T3 11.6 min (1.77). T2 took 13.6 min (1.07) to reach 39°C. T1 and T3 were within ±1°C at 5.1 min (0.6). A biphasic relationship demonstrated the time lag between the temperatures of the heated patient circuit and the humidifier chamber. T3 strongly correlated to T1 when T1 is ≥28°C (r(2)=0.85). Humidity was difficult to measure and results were inferred from temperature recordings. CONCLUSION This in vitro test showed that heated, humidified gas is possible during neonatal resuscitation. Adequate time must be allowed for the humidifier chamber to warm to near optimal temperature. The patient circuit is initially heated faster than the humidifier chamber. The displayed T1 temperature correlates to the temperature at T3 at ≥28°C.
Collapse
Affiliation(s)
- Andrew D Shearman
- Department of Newborn Services, Mater Mothers' Hospital, South Brisbane, Australia.
| | | | | | | |
Collapse
|
18
|
Abstract
A recent systematic review and meta-analysis shows that volume-targeted ventilation (VTV) compared with pressure-limited ventilation (PLV) reduce death and bronchopulmonary dysplasia, pneumothorax, hypocarbia and severe cranial ultrasound abnormalities. In this paper, we present published research and our experience with volume guarantee (VG) ventilation, a VTV mode available on the Dräger Babylog 8000plus and VN500 ventilators. The VG algorithm measures the expired tidal volume (V(T)) for each inflation and adjusts the peak inflating pressure for the next inflation to deliver a V(T) set by the clinician. The advantage of controlling expired V(T) is that this is less influenced by endotracheal tube leak than inspired V(T). VG ventilation can be used with an endotracheal tube leak up to ∼50%. Initial set V(T) for infants with respiratory distress syndrome should be 4.0 to 5.0 ml kg(-1). The set V(T) should be adjusted to maintain normocapnoea. Setting the peak inflating pressure limit well above the working pressure is important to enable the ventilator to deliver the set V(T), and to avoid frequent alarms. This paper provides a practical guide on how to use VG ventilation.
Collapse
|
19
|
te Pas AB, Lopriore E, Dito I, Morley CJ, Walther FJ. Humidified and heated air during stabilization at birth improves temperature in preterm infants. Pediatrics 2010; 125:e1427-32. [PMID: 20457686 DOI: 10.1542/peds.2009-2656] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE Neonatal resuscitation guidelines recommend techniques to minimize heat loss in the delivery room. The use of humidified and heated gas is standard of care for preterm infants who need respiratory support in the NICU, but international resuscitation guidelines do not stipulate use of this therapy during stabilization at birth. We aimed to investigate the effect of humidified and heated gas on admission temperature in preterm infants who require respiratory support at birth. METHODS Two cohorts of very preterm infants born at < or = 32 weeks' gestational age in the Leiden University Medical Center were compared prospectively before (the "cold" cohort) and after (the "heated" cohort) introduction of the use of heated and humidified gas during respiratory support at birth (continuous positive airway pressure or intubation). The primary outcome was the infant's rectal temperature at admission in the NICU. RESULTS There was a difference in the mean (SD) rectal temperature between the cold and heated cohorts (35.9 [0.6] vs 36.4 [0.6], respectively; P < .0001). Normothermia (36.5 degrees C-37.5 degrees C) occurred less often in the cold cohort than in the heated cohort (12% vs 43%; P < .0001). There was no difference in occurrence of mild hypothermia (36.0 degrees C-36.4 degrees C) between groups (33% vs 35%; not significant). Moderate hypothermia (<36.0 degrees C) occurred more often in the cold cohort (53% vs 19%; P < .001). CONCLUSIONS The use of heated and humidified air during respiratory support in very preterm infants just after birth reduced the postnatal decrease in temperature. Heating and humidifying the gas during stabilization merits additional investigation.
Collapse
Affiliation(s)
- Arjan B te Pas
- Department of Pediatrics, Leiden University Medical Center, J6-S, PO Box 9600, 2300 RC Leiden, Netherlands.
| | | | | | | | | |
Collapse
|
20
|
Pillow JJ, Hillman NH, Polglase GR, Moss TJM, Kallapur SG, Cheah FC, Kramer BW, Jobe AH. Oxygen, temperature and humidity of inspired gases and their influences on airway and lung tissue in near-term lambs. Intensive Care Med 2009; 35:2157-63. [PMID: 19756508 DOI: 10.1007/s00134-009-1624-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 08/07/2009] [Accepted: 08/07/2009] [Indexed: 11/25/2022]
Abstract
PURPOSE The relative contributions of factors influencing lung injury immediately after birth are poorly understood. We hypothesized that oxygen content and humidity of inspired air would influence markers of pulmonary inflammation in ventilated lambs. METHODS Lambs delivered at 140 days gestation (term = 150 days) were assigned to one of five groups (n = 5-6/group): unventilated controls, or ventilation with 21 or 100% O(2) that was either heated and humidified or cold and dry. Lambs were ventilated gently for 3 h: blood gases were recorded regularly. Bronchoalveolar lavage and samples of tracheal mucosa and lung were collected post mortem. RESULTS Arterial pH was lower [mean difference (95% CI): -0.07 (-0.13, -0.03)], while there was an increase in PaCO(2) [mean difference (95% CI): 10.2 (2.4, 17.9)] and fold change in lung pro-inflammatory IL-1beta cytokine mRNA [mean difference (95% CI): 28.3 (0.3, 56.2)] or IL-8 [mean difference (95% CI): 27.8 (7.9, 47.7)] cytokine mRNA expression with 100% O(2) relative to 21% O(2). Cold dry inspired gas did not influence gas exchange or dynamic mechanics at 3 h compared to heated humidified gas. Compared to 100% inspired O(2), cold dry inspired gas had less marked effect on fold change in lung pro-inflammatory IL-1beta cytokine mRNA [mean difference (95% CI): 27.2 (-0/8, 55.1)] or IL-8 [mean difference (95% CI): 14.5 (5.5, 34.4)] cytokine mRNA expression, although cilial dysfunction/damage was evident on electron microscopy, especially when exposure to cold dry gas was combined with hyperoxia. CONCLUSIONS In near-term neonatal lambs ventilated for 3 h, hyperoxia was associated a more powerful stimulus for pulmonary dysfunction and upregulation of inflammatory cytokines than cold dry gas.
Collapse
Affiliation(s)
- J Jane Pillow
- School of Women's and Infants' Health, The University of Western Australia, Subiaco, Perth 6008, Australia.
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Nagaya K, Okamoto T, Nakamura E, Hayashi T, Fujieda K. Airway humidification with a heated wire humidifier during high-frequency ventilation using Babylog 8000 plus in neonates. Pediatr Pulmonol 2009; 44:260-6. [PMID: 19208373 DOI: 10.1002/ppul.20990] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Little data are available on airway humidity during high-frequency ventilation (HFV). Our purpose is to evaluate the airway humidification during HFV. METHODS We examined the airway humidification and temperature in a neonatal HFV system using Babylog 8000 plus. The absolute humidity (AH), relative humidity (RH), and temperature at different sites and under different HFV conditions were compared with those during conventional intermittent positive pressure ventilation (IPPV). RESULTS The mean AH and RH at the patient end of the respiratory circuit under 37 degrees C in the humidification chamber (HC) during HFV were less than 35 mg/L and 65%, respectively, while those during IPPV were 42.3 mg/L and 96.8%, respectively. The humidification at the outlet of the HC was similar results. Moreover, during HFV an increase in the bias-flow of ventilator led to a further decrease in the humidity at the patient end of respiratory circuit and the outlet of HC. It was necessary to set the temperature in the HC at >39 degrees C to maintain adequate humidity at the HC and the patient end of respiratory circuit during HFV. An increase in the incubator temperature led to an increase in the temperature at the patient end of the respiratory circuit. The temperature at the patient end of the respiratory circuit was about 39-40 degrees C when the incubator temperature was 35-37 degrees C. CONCLUSIONS The airway humidification at the patient end of respiratory circuit and the outlet of HC in HFV were poorer than those in IPPV. However, the adequacy of humidification and safety in HFV remain to be demonstrated in clinical practice.
Collapse
Affiliation(s)
- Ken Nagaya
- The Center for Maternity and Infant Care, Asahikawa Medical College, Midorigaoka-higashi, Asahikawa, Hokkaido, Japan.
| | | | | | | | | |
Collapse
|
22
|
Yamada Y, Kyuno T, Suzuki S, Ito T, Kato I, Togari H. A drop in gas temperature in the external part of the endotracheal tube is problematic during neonatal respiratory support. Pediatr Pulmonol 2008; 43:666-73. [PMID: 18500729 DOI: 10.1002/ppul.20836] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
During neonatal respiratory support, maintaining optimal humidity minimizes the risk of airway occlusion and chronic lung disease. With neonatal respiratory support using a heated humidifier,condensation following decreases in temperature within the unheated part of the inspiratory circuit represents a serious problem, due to the resulting drop in absolute humidity. Several reports describing the temperature/humidity gradient in the unheated inspiratory limb have excluded the endotracheal tube (ETT). The present study investigated the extent to which the temperature gradient in the ETT affects breathing gas conditioning in premature infants, who display tiny minute volumes. By measuring temperature/dew point at various sites along the inspiratory circuit, including inside the ETT, we evaluated the effects of temperature change in the ETT using an in vitro model of a micropremie on mechanical respirator care in an incubator. We confirmed significant moisture loss (absolute humidity loss; 7.5-10.1 mg/L) with decreasing gas temperature in the ETT external to the body, with subsequent drying of the gas (relative humidity drop, 10.7-22.3%) as temperature increased in the ETT inside the body. The present results suggest that temperature decreases in the ETT represent an important issue in the respiratory care of very premature infants.
Collapse
Affiliation(s)
- Yasumasa Yamada
- Department of Neonatology, Central Hospital, Aichi Human Service Center, Kasugai, Aichi 480-0392, Japan.
| | | | | | | | | | | |
Collapse
|