HFOV Case Study 3.6kg MAS Student Copy Color key: Black – Patient case Blue – RN/RCP collaboration Red – MD consult Green - Critical Thinking Inquiry Green italics – CT answers ABG: pH/PCO2/PO2/Base

A 35 year-old primigravida, whose pregnancy had been thus far uncomplicated, was admitted to the hospital for induction of labor at 41 weeks’ gestation. An ultrasonographic scan suggested the presence of oligohydramnios, and induction of labor with oxytocin was successful. Electronic fetal heart rate monitoring disclosed both late and variable decelerations. Artificial rupture of the membranes produced thick, meconium-stained amniotic fluid. An amnioinfusion was done to help relieve the fetal heart decelerations, but there was little progress and a primary cesarean section was performed. A 3.6 kg male infant was delivered. The baby was very floppy at birth and was covered by yellow-green meconium. No respiratory effort was noted. The heart rate was 70 beats/min, the baby’s color was very dusky, and he had poor peripheral perfusion. The infant was intubated and suctioned with the retrieval of a significant amount of particulate meconium. Positive pressure ventilation was given. HR 130 | FIO2 .6 | O2SAT: 92% Umbilical ABG: 7.03/77/14 CXR: Dense, fluffy infiltrates

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CT: CXR indicative of? RN/RCP: Asses pt, breath sounds, patent and secure airway, vital signs MD: Order for mechanical ventilation CMV: TCPL: Rate 60 | IT .5 | PIP 28 | PEEP 6 | FIO2 1.0 ABG: 7.29/55/48 CT: What is the next step? (Meconium contains numerous noxious chemical constituents, particularly bile salts, which have been shown to inactivate surfactant. Small clinical trials have shown a favorable benefit to both administration of surfactant and lung lavage with surfactant, but this is not yet an approved indication) HFOV might be an option at this time, although great care is necessary to avoid gas trapping and hyperinflation. MD: Decides to increase rate, increase PIP and Peep, and increase IT. TCPL: Rate 70 | IT .6 | PIP 30 | PEEP 6 | FIO2 1.0 Note the graphic monitoring:

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CT: What abnormality is present on this waveform? Shortly thereafter, the patient had an acute deterioration. Another CXR was obtained.

CT: Interpret this CXR MD: At bedside placing a chest tube RN/RCP: RN starting dopamine to support blood pressure. RCP assessing oxygenation status via pulse oximeter. ABG: 7.10/65/34 CT: What is the next step? Pre ductal O2 SAT: 91% | Post ductal O2 SAT: 74% CT: So, what does this indicate? RN: Fluid bolus is given for a mean arterial blood pressure of 39. Dopamine is increased and dobutamine is added. MD: Cardiologist is now at bedside performing an echocardiogram. Results of ECHO: PDA, and PFO, with subsequent R to L shunting. Inhaled Nitric Oxide (iNO) was started at 20 ppm. There was no change in the patient’s condition. Pre ductal O2 SAT: 89% | Post ductal O2 SAT: 72% | BP: 60/40, mean 48 Repeat CXR: no pneumothorax. Diminished lung volumes noted. CT: What would you do next? CT: What would be the appropriate settings to start with and why? CT: What are the potential complications of HFOV with this patient? MD: Agrees with your recommendation and asks you to place on HFOV. CT: What do you need to do before switching to HFOV? HFOV: MAP: 20 | AMP: 40 | Hz: 10 | FIO2: 1.0 (actual read out .96 iNO) CT: Now what? It has been 8 minutes since the initiation of HFOV and O2 SAT is 84%. Blood pressure is adequate.

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What should you be thinking about? O2 SAT: 88% | tcCO2: 60 | Bp: 60/42 What is the next step and why? ABG: 7.32/58/99 CXR: Expanded to 8 ribs, ETT at T2, no recurrence of pneumothorax CT: Response to the above information? RN/RCP: Both of you are at the beside and determine that chest wiggle is indeed, from clavicles to umbilicus, maybe even slightly beyond the umbilicus. CT: Need for reassessment of CO2 removal. HFOV: MAP: 20 | AMP: 40 | Hz: 8 | FIO2: 1.0 (actual read out .96 iNO) CT: The next step? Within this next hour, you come to the bedside because the high pressure alarm is sounding and the MAP is not holding. You note that the dump valve is open to ambient air with each breath and the oscillator is stopped. RN/RCP: Note that the flexible circuit has quite a bit of water sloshing in it. You quickly drain the water back to the water trap. CT: What do you do now? Piston starts and MAP is maintained. ABG: 7.37/50/103 CT: At this time, what should you be thinking and why? Over the next 3 days, the patient has been able to be weaned successfully. CT: Discuss the course of weaning HFOV settings. The patient continued to wean steadily. The iNO was also weaned successfully. The baby was transitioned back to conventional ventilation. The right chest tube was subsequently removed. This case represents a common problem still seen in most tertiary neonatal intensive care units. Meconium aspiration syndrome is a condition associated with both prolonged pregnancy and fetal distress. It may result in meconium staining (meconium on the baby but not in the airway), meconium aspiration (meconium found in the airways), or meconium aspiration syndrome (meconium in the airway, respiratory distress, and a compatible chest radiograph). The latter condition may be complicated by the development of chemical or bacterial pneumonia, or, as in this case, PPHN, a severe and life-threatening condition, in which pulmonary vascular resistance fails to fall, resulting in right-to-left shunting through the PDA and PFO and severe ventilation/perfusion mismatch, resulting in profound hypoxemia. References 1. Kattwinkel J (ed.). Neonatal Resuscitation, 5th edition. Elk Grove Village, IL. American Academy of Pediatrics-American Heart Association, 2006. 2. Wiswell TE. Meconium aspiration syndrome. In Donn SM and Sinha SK (eds.). Manual of Neonatal Respiratory Care, 2nd edition. Philadelphia, Mosby Elsevier, 2006, pp. 325-330. 3. Moses D, Holm B, Spitale P, et al. Inhibition of pulmonary surfactant function by meconium. Am J Obstet Gynecol 1991; 164:477-481. 4. Andersson S, Kheiter A, Merritt TA. Oxidative inactivation of surfactants. Lung 1999; 177:179-189.

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5. Lotze A, Mitchell BR, Bulas DI, et al. Multicenter study of surfactant (beractant) use in the treatment of term infants with severe respiratory failure. Survanta in Term Infants Study Group. J Pediatr 1998; 132:4047. 6. Wiswell TE, Knight GR, Finer NN, et al. A multicenter, randomized, controlled trial comparing Surfaxin (Lucinactant) lavage with standard care for treatment of meconium aspiration syndrome. Pediatrics 2002; 109:1081-1087. 7. Donn SM. Pressure control ventilation. In Donn SM and Sinha SK (eds.). Manual of Neonatal Respiratory Care, 2nd edition. Philadelphia, Mosby Elsevier, 2006, pp. 210-211. 8. Donn SM, Bandy KP. Volume-controlled ventilation. In In Donn SM and Sinha SK (eds.). Manual of Neonatal Respiratory Care, 2nd edition. Philadelphia, Mosby Elsevier, 2006, pp. 206-209. 9. Nelson M, Becker MA, Donn SM. Basic neonatal respiratory disorders. In Donn SM (ed.). Neonatal and Pediatric Pulmonary Graphics. Principles and Clinical Applications. Armonk, NY, Futura Publishing Co., 1998, pp. 253-277. 10. Schumacher RE, Donn SM. Persistent pulmonary hypertension of the newborn. In In Donn SM and Sinha SK (eds.): Manual of Neonatal Respiratory Care, 2nd edition. Philadelphia, Mosby Elsevier, 2006, pp. 331-336. 11. Philip AGS. Neonatology, A Practical Guide, 2nd edition. Flushing, NY, Medical Examination Publishing Co., 1980, pp. 127- 130. 22 12. Guthrie SO, Walsh WF, Auten K, Clark RH. Initial dosing of inhaled nitric oxide in infants with hypoxic respiratory failure. J Perinatol 2004; 24:290-294. 13. Donn SM. Neonatal shock and hypotension. Arch Perinatal Med 2005; 11:16-18. 14. Kinsella JP, Abman SH. Clinical approach to the use of high frequency oscillatory ventilation in neonatal respiratory failure. J Perinatol 1996; 16:S52-55. 15. Donn SM, Gates MR. Transport of ventilated babies. In In Donn SM and Sinha SK (eds.). Manual of Neonatal Respiratory Care, 2nd edition. Philadelphia, Mosby Elsevier, 2006, pp. 487- 496. These case studies are for reference only. Each patient is unique and may require different care.

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