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An international survey of volume-targeted neonatal ventilation

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An international survey of volume-targeted neonatal ventilation
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  Short report  Arch Dis Child Fetal Neonatal Ed 2011; 96 :F146–F148. doi:10.1136/adc.2009.181081F146 1 Newborn Services, Royal Women’s Hospital, Melbourne, Australia 2 Department of Paediatrics, University Hospital of North Norway, Tromsø, Norway 3 Department of Paediatrics, Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway 4 Murdoch Children Research Institute, Melbourne, Australia 5 Department of Physiology, Monash University, Melbourne, Australia 6 Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Australia Correspondence to Claus Klingenberg, Neonatal Services/Department of Newborn Research, Royal Women’s Hospital, 20 Flemington Road, Parkville, Melbourne, Victoria 3052, Australia; claus.klingenberg@unn.noAccepted 8 March 2010Published Online First 28 June 2010 ABSTRACTObjective  To evaluate clinical practice of volume-targeted ventilation (VTV). Design Internet-based survey of all 50 tertiary neonatal units in Australia, New Zealand, Sweden, Denmark, Finland and Norway. Results  Response rate was 100%. VTV was routinely used in 25 (50%) units; 15/25 (60%) in Australasia and 10/25 (40%) in the Nordic countries. The most common reason given for using VTV was that it reduces bronchopulmonary dysplasia (13/25; 52%). The median (IQR) of upper limits of target tidal volume were (1) for initial ventilation of preterm infants with respiratory distress syndrome 5.0 (4.6–6.0) ml/kg and (2) for infants with ventilator-dependent bronchopulmonary dysplasia 6.0 (5.0–8.0) ml/kg. The median (IQR) maximum peak inspiratory pressure limit units were prepared to use in VTV-mode was 35 (30–42.5) cm H 2 O. Conclusion  Half of the units used VTV routinely, but with a considerable variation in VTV practice. More studies are required to establish best VTV practice. Pressure-limited ventilation (PLV) has been the primary mode of neonatal mechanical ventila-tion for the last four decades. During PLV, tidal volume (V  T ) delivery fluctuates due to variations in lung compliance and respiratory effort. This may lead to overexpansion (volutrauma) or low  V  T , with increased work of breathing and acido-sis. 1  Modern microprocessor-controlled ventila-tors allow volume-targeted ventilation (VTV) with reduced V  T  variability. 2  Systematic review has shown that VTV, compared with PLV, reduces duration of ventilation, rate of pneumothorax and rate of severe intraventricular haemorrhage. 3  However, different VTV-modes make interpre-tation of evidence difficult. The objective of this survey was to evaluate clinical practice of VTV in the Nordic countries and Australasia. METHODS A web-based email survey (Appendix A) was sent to the lead neonatologists at all 50 tertiary neonatal units in Australia (19), New Zealand (6), Sweden (8), Denmark (3), Finland (5) and Norway (9). Questions included the annual number of extremely low birth weight infants admitted, the ventilators in use and ventilator-settings for initial management of intubated preterm infants with respiratory distress syndrome (RDS). Units using VTV were asked about perceived benefits of VTV, selection and adjustment of ventilator settings for different clinical scenarios and their An international survey of volume-targeted neonatal ventilation Claus Klingenberg, 1–3  Kevin I Wheeler, 1,4,5  Louise S Owen, 1,4  Per I Kaaresen, 2,3  Peter G Davis 1,4,6 approach to weaning. Units not using VTV were asked why they did not use this mode. Follow-up for non-responders was by email and phone. A second consultant was approached if needed. RESULTS Response rate was 100%. For intubated preterm infants with RDS on the first day of life, initial respiratory support was provided using conven-tional ventilation in 49 units (98%) and high-frequency ventilation in one unit (2%). All units using conventional ventilation used a synchro-nised mode with inspiratory triggering; 37/49 (75.5%) assist-control (AC) and 12/49 (24.5%) syn-chronized intermittent mandatory ventilation.Twenty-five units (50%) routinely used VTV; Australia (12/19; 63%), New Zealand (3/6; 50%), Sweden (1/8; 12.5%), Denmark (3/3; 100%), Finland (1/5; 20%), Norway (5/9; 55.5%). There was no correlation between the size of the unit and likelihood of routine VTV use. Twenty of the 25 (80%) units using VTV used the Dräger Babylog 8000 plus in Volume Guarantee (VG) mode. VTV was mainly used in conjunction with AC-mode (21/25; 84%).Fourteen of 25 (56%) units using VTV responded that the most important benefit of  VTV was to reduce bronchopulmonary dyspla-sia (BPD). Other reasons considered important by at least 40% of the units using VTV included What is already known on this topic ▶   Evidence suggests that volume-targeted ventilation (VTV), compared with pressure-limited ventilation, improves outcomes in preterm infants. ▶   Previous studies within Europe have reported a low use of VTV. What this study adds ▶  VTV is currently used in half of all tertiary units in Australasia and the Nordic countries. ▶  Differences in use and variation in clinical practice indicate the need for further trials delineating best volume targeting practice.  group.bmj.comon February 25, 2011 - Published by fn.bmj.comDownloaded from   Short report  Arch Dis Child Fetal Neonatal Ed 2011; 96 :F146–F148. doi:10.1136/adc.2009.181081F147 limit at the same level as PIP used prior to VTV. Twenty-three of 25 units (92%) would further increase the PIP-limit if tar-get V  T  was not being achieved. The maximum PIP-limits that units were prepared to use are shown in fig 1A.Units were asked to specify their lower and upper limits of target V  T  for different clinical scenarios (table 1). There were no differences in target V  T  settings between preterm infants with a birth weight of 600 and 1200 g. For infants with ven-tilator-dependant BPD, the upper limit target V  T  was higher than for the other clinical situations. The maximum target V  T  that units were prepared to use ‘in extremis’ is shown in fig 1B. Twelve of 25 (48%) units reported reducing target V  T  as part of their weaning strategy, however the reported values were not statistically different from target V  T  for RDS on day 1 (table1). DISCUSSION This survey reports neonatal VTV practice from all tertiary units in six countries in two different geographical regions. Half of the units routinely used VTV for preterm infants with RDS. Lung compliance changes rapidly after birth and VTV use may reduce volutrauma at this time. The use of VTV in this survey is higher than reported from the UK in 2007, where only 5% of neonatal units used VTV. 4  VTV use varied across the countries surveyed, with only 2 of 13 units in Sweden and Finland using the technique. Many centres in these countries believed there is insufficient evi-dence of benefit of VTV over other ventilation modes. This may reflect the lack of large multi-centre trials comparing VTV to PLV. Good experience with their current practice was also a common reason for not using VTV.We found that the commonly used lower and upper target V  T  for preterm infants with RDS were 3.5–4.0 and 5.0–6.0 ml/kg, respectively. Some units quoted much wider ranges and most units reduced target V  T  when weaning. There are few data regarding the most appropriate target V  T  for preterm infants of different weights, ages and lung pathologies or how best to wean in this mode. However, reducing target V  T  to low set values (ie 3.0–3.5 ml/kg) may result in periods of endotracheal continuous positive airway pressure and increased work of breathing. 1 5  Data from an observational study of extremely low birth weight infants (<800 g) suggested that expired V  T  values ~5 ml/kg are required to maintain normocapnoea in first week of life. 6   In the same study population the V  T /kg required for normocapnoea was inversely related to birth weight, probably due to a relatively increased effect of the fixed instrumental dead space in the smallest infants. 7  In our survey, however, units did not seem to use different V  T  for infants with RDS of different weights. There is also observa-tional evidence that older infants need higher V  T  to maintain normocapnoea, interpretation of this information may be why most units were prepared to use higher target V  T  for infants with BPD. 6  (1) more stable CO 2 , (2) reduction in air leak, (3) reduced need for blood gases and (4) easier weaning. The main reasons for not using VTV were the belief that clinical outcomes using their current ventilation strategy were good (13/25; 52%) or that there was insufficient evidence of benefit of VTV (11/25; 44%). Three units reported not having ventilators capable of delivering VTV.Twelve of 25 (48%) units using VTV set the maximum peak inspiratory pressure (PIP) limit during VTV 2–5 cm H 2 O above the PIP needed to achieve target V  T , and 11 (44%) set the PIP Figure 1 Maximum limits for (A) peak inspiratory pressure (top) and (B) target V T  (bottom) peak inspiratory pressure (right) that the 25 units using volume-targeted ventilation were prepared to use in extreme clinical situations (categorical axes). Maximum target V T  (ml/kg) usedMaximum PIP-limit (cm H 2 O) used    N  u  m   b  e  r  o   f  u  n   i   t  s   N  u  m   b  e  r  o   f  u  n   i   t  s AB Table 1 Lower and upper limits of target V T  for four different clinical scenarios  Lower limit target V T  (ml/kg)Upper limit target V T  (ml/kg)MedianIQRRangeMedianIQRRange Birth weight 600 g and RDS (n=22)4.03.4–4.02.0–5.05.04.9–6.04.0–8.0Birth weight 1200 g and RDS (n=22)4.03.5–4.02.0–5.05.254.5–6.04.0–6.0Weaning (n=24)3.753.5–4.03.0–5.05.04.5–6.04.0–8.0Ventilator-dependent BPD (n=20)4.03.5–4.42.0–6.06.0*5.0–8.04.0–10.0*Upper limit target V T  for BPD was higher in comparison to upper limit for RDS and weaning, p=0.045 by Mann–Whitney test.BPD, bronchopulmonary dysplasia; RDS, respiratory distress syndrome; V T , tidal volume.  group.bmj.comon February 25, 2011 - Published by fn.bmj.comDownloaded from   Short report  Arch Dis Child Fetal Neonatal Ed 2011; 96 :F146–F148. doi:10.1136/adc.2009.181081F148  Ventilators offering VTV differ substantially in how they measure and control V  T  delivery, the clinical benefits and risks of which have not yet been studied. The most commonly reported form of VTV used in this study was the VG mode on the Dräger Babylog 8000 plus. As units become experienced with this particular mode of VTV delivery, trials comparing  VG mode with other ventilation strategies will become more difficult to conduct.Our intention with this survey was to identify unit practice. We asked specifically for the ‘policy of the unit’. However, as a single neonatologist answered the survey on behalf of each unit, personal preference cannot be excluded. Data on actual target V  T  used during clinical care was not collected so caution should be used when comparing our results with studies reporting specific target V  T . The 100% response rate from all tertiary neonatal units surveyed provides an updated overview of the breadth of neonatal VTV strategies used in these six countries at the end of 2009. CONCLUSION As evidence supporting VTV has emerged, use of the tech-nique has increased. Half of the units in the six countries surveyed now routinely use VTV for preterm infants with RDS. Evidence regarding the optimal range of target V  T  in different clinical situations is limited and there is a range of clinical practice. Further trials to identify optimal VTV deliv-ery and target V  T  in different patient populations are urgently needed. Acknowledgements The authors thank Jeanie Cheong for critically reading the manuscript and the following neonatal units for providing data for this survey. In Australia  The Townsville Hospital, Townsville; Mater Mothers’ Hospital, Brisbane; Royal Brisbane and Women’s Hospital, Brisbane; John Hunter Children’s Hospital, Newcastle; Royal Prince Alfred Hospital, Sydney; Nepean Hospital, Sydney; Liverpool Hospital, Liverpool; Royal Hospital for Women, Sydney; Royal North Shore Hospital, Sydney; Westmead Hospital, Sydney; The Canberra hospital, Canberra; Mercy Hospital for Women, Melbourne; Monash Medical Centre, Melbourne; The Royal Women’s Hospital, Melbourne; Royal Hobart Hospital, Hobart; Flinders Medical Centre, Adelaide; Women’s and Children’s Hospital, Adelaide; King Edward Memorial Hospital for Women, Perth; Princess Margaret Hospital for Children, Perth. In New Zealand  National Women’s Health, Auckland; Middlemore Hospital, Auckland; Waikato Hospital, Hamilton; Wellington Regional Hospital, Wellington; Christchurch Women’s Hospital, Christchurch; Dunedin Hospital, Dunedin. In Sweden  Örebro University hospital, Örebro; Karolinska University Hospital-Astrid Lindgren Solna, Stockholm; Karolinska University Hospital-Huddinge, Stockholm, Sahlgrenska University Hospital, Gothenburg; Linköping University Hospital, Linköping; Norrland University Hospital, Umeå; Uppsala University Hospital, Uppsala; Lund University Hospital, Lund. In Denmark  Odense University Hospital, Odense; Rigshospitalet, Copenhagen; Århus University Hospital, Århus. In Finland  Helsinki University Central Hospital, Helsinki; Turku University Hospital, Turku; Oulu University Hospital, Oulu; Kuopio University Hospital, Kuopio; Tampere University Hospital, Tampere. In Norway  Oslo University Hospital-Rikshospitalet, Oslo; Oslo University Hospital-Ullevål, Oslo; Akershus University Hospital, Lørenskog; Stavanger University Hospital, Stavanger; Haukeland University Hospital, Bergen; Health Sunnmøre Trust, Ålesund, St. Olav University Hospital, Trondheim; Nordland Central Hospital, Bodø; University Hospital of North Norway, Tromsø. Funding KIW is supported in part by a Monash International Postgraduate Research Scholarship. PGD is supported in part by an Australian National Health and Medical Research Council Practitioner Fellowship. The research was funded by Australian National Health and Medical Research Council Program Grant no. 384100. Competing interests  None. Provenance and peer review  Not commissioned; externally peer reviewed. REFERENCES  1. Keszler   M . State of the art in conventional mechanical ventilation.  J Perinatol   2009; 29 :262–75. 2. Keszler   M , Abubakar K. Volume guarantee: stability of tidal volume and incidence of hypocarbia.  Pediatr Pulmonol   2004; 38 :240–5. 3. McCallion N , Davis   PG, Morley   CJ. Volume-targeted versus pressure-limited ventilation in the neonate. Cochrane Database Syst Rev   2005; 3 :CD003666. 4. Sharma   A , Greenough A. Survey of neonatal respiratory support strategies.  Acta Paediatr   2007; 96 :1115–17. 5. Patel   DS , Sharma A, Prendergast M, et al.  Work of breathing and different levels of volume-targeted ventilation.  Pediatrics  2009; 123 :e679–84. 6. Keszler   M , Nassabeh-Montazami S, Abubakar K. Evolution of tidal volume requirement during the first 3 weeks of life in infants <800 g ventilated with Volume Guarantee.  Arch Dis Child Fetal Neonatal Ed   2009; 94 :F279–82. 7. Nassabeh-Montazami   S , Abubakar KM, Keszler M. The impact of instrumental dead-space in volume-targeted ventilation of the extremely low birth weight (ELBW) infant.  Pediatr Pulmonol   2009; 44 :128–33.  group.bmj.comon February 25, 2011 - Published by fn.bmj.comDownloaded from   doi: 10.1136/adc.2009.181081 published online June 28, 2010 2011 96: F146-F148 srcinally Arch Dis Child Fetal Neonatal Ed   Claus Klingenberg, Kevin I Wheeler, Louise S Owen, et al.  neonatal ventilationAn international survey of volume-targeted   http://fn.bmj.com/content/96/2/F146.full.html Updated information and services can be found at: These include:  References   http://fn.bmj.com/content/96/2/F146.full.html#ref-list-1 This article cites 6 articles, 2 of which can be accessed free at: serviceEmail alerting the box at the top right corner of the online article.Receive free email alerts when new articles cite this article. Sign up in Notes   http://group.bmj.com/group/rights-licensing/permissions To request permissions go to:  http://journals.bmj.com/cgi/reprintform To order reprints go to:  http://group.bmj.com/subscribe/ To subscribe to BMJ go to:  group.bmj.comon February 25, 2011 - Published by fn.bmj.comDownloaded from
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