HFOV Case Study 834 Gram Infant Instructor 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
834 gram white female born via cesarean section at 27 weeks’ gestation secondary to maternal unstable pre-eclampsia. The patient’s mother was a 22 year old whose unstable pre-eclampsia was initially managed with magnesium sulfate. When this was unsuccessful in controlling the high blood pressure, she was taken to the OR for a C-section. Apgar scores were 5/8. An umbilical artery catheter was placed for arterial blood gas and blood pressure monitoring. An umbilical venous catheter was placed for IV access. Care plan included maintenance IV fluids, amp/gent. CT: Possible diagnoses? RDS
Intubated with a 3.0 ETT/7cm at the lip | HR 180 | RR 78 | BP 44/24 CMV: PIP 20 | PEEP 5 | Rate 60 | IT 0.4 | FIO2 0.6 CXR = bilateral reticulogranular pattern, questionable rim of air on the right lower cardiac border
Surfactant was administered at this time—100ml/kg ABG: 7.49/23/44/-3.2 | tcCO2 30 | O2 SAT: 80% RN/RCP: discuss sat goals for patient, assess breath sounds, markedly diminished bilaterally MD called: Rate 50, FIO2 0.7
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CT: Response to vent order—What is VT? Can the Vt be measured on the current ventilator? If so, is it 4-6ml/kg? What is the optimum lung inflation? 8-9 ribs inflation 2000
CMV: PIP 20 | PEEP 5 | Rate 40 | IT 0.4 | FIO2 0.7 | tcCO2 70 | O2 SAT 60% RN/RCP: Discuss possibilities of sudden change in vital signs MD called to bedside CT: Possible diagnosis? Think about sudden vs gradual. Pneumothorax, ETT plugged, cardiac? Get a STAT CXR CXR: Right sided Pneumothorax
One chest tube placed. Four hours later, the patient developed acute distress requiring chest compressions, IV sodium bicarbonate and epinephrine was administered through the ETT. ABG: 7.0/65/27/-8 | tcCO2 80 | O2SAT 56% CT: What’s happening with this patient. Note the acute onset of the code and follow up ABG. Worsening of current pneumothorax, another subsequent tension pneumothorax? CXR: Left sided tension pneumothorax that has partially re-expanded after chest tube placement
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MD: Order for HFOV CT: What would be the appropriate initial HFOV settings? Why? FIO2 1.0, MAP lower than CMV (low lung strategy because of air leaks), AMP for adequate CW (clavicles to umbilicus), Hz 15 because of weight. What are potential complications of HFOV? Air trapping/hyperinflation/air leak/hemodynamic compromise/IVH What do we need before switching to HFOV? Vital signs/Assessment, heightened awareness of safety and stable airway, positioning and immobility, firm mattress, suction
HFOV: FIO2 1.0 | MAP 13 | Amp 20 | Hz 15 CT: Response to HFOV? What to look for? Adequate CWF, O2 SATS improving? tcCO2, Bp, hemodynamics, color
2210 CXR reveals changes consistent with pulmonary interstitial emphysema and bilateral pneumothoraces. 0100
ABG: 7.44/46/89/+1 | tcCO2 49 | O2 SAT 91% RN/RCP discuss the need for suctioning and agree to used closed suction maneuver. MD: Wean FIO2 for sats >92%, adjust amp to keep PCO2 50 and for adequate CW CT: How long since surfactant was given? Just need to be thinking about this. What are potential adverse effects of suctioning pt. on HFOV? Loss of lung volume (especially if the baby does not return to baseline very quickly), atelectasis, ETT dislodgment Why is the FIO2 being weaned before the MAP? Oxygen toxicity
48 hours old: HFOV: FIO2 0.4 | MAP 10 | AMP 18 | Hz 15 The patient was positioned with left side down because the air leak appeared on CXR to be worse there. Follow up CXR 12 hours later reflected dramatic improvement in the air leak and healing PIE. ABG: 7.46/41/80/+1 CT: What assessments are needed at this time. What ventilatory changes need to be made? Has the patient now been stable for at least 24 hours? Can you touch, turn without compromising patient and vital signs? Is chest wiggle still from clavicle to umbilicus. Start thinking about hyperinflation once lungs are healed. Could decrease AMP further. Wait and watch!
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76 hours old: CXR indicated almost complete resolution of the air leak on the left side. HFOV continues to be weaned. CT: When do we start thinking about changing back to conventional Ventilation or extubation? As long as the patient has been stable for 24 hours, can touch and turn without incident. With the above HFOV settings, could switch patient back to conventional ventilation/extubation What vent settings would you choose? FIO2 25-30%, Rate 30, PIP 18-20, PEEP 4, IT 0.4. Observe SATS and tcCO2. Consider extubation to NCPAP? The use of a lower airway pressure with HFOV provided significant advantages for this patient. HFOV may be suggested not only to prevent, but also to resolve, air leak syndrome in neonatal patients with RDS. Perhaps the greatest lesson learned in HFOV research, to date, is the critical importance of proper ventilator-management strategy. Through their work with more than 400 critically ill neonates, Clark et al,9 identified four categories of illness to be supported using HFOV: diffuse homogeneous lung disease, non-homogeneous lung disease, lung hypoplasia syndrome, and air leak syndrome. Based on their experience, they advocated the use of a low-pressure management strategy for patients with severe air leak. References 1. Varnholt V, Lasch P, Kachel W, Diehm T, Koelfen W. High frequency oscillatory ventilation of infants with severe respiratory disorders: possibilities, risks and limits. Klin Padiatr. 1994;206:161-166. 2. Miyahara K, Ichihara T, Watanabe T. Successful use of HFOV for pneumomediastinum. Ann Thorac Cardiovasc Surg. 1999;5:49-51. 3. Clark RH, Gertsmann DR. Controversies in high frequency ventilation: controversies in neonatal pulmonary care. Clin Perinatol. 1998;25:113-122. 4. Coalson JJ, deLemos RA. Pathologic features of various ventilatory strategies. Acta Anaesthesiol Scand Suppl. 1989;90:108-116. 5. Helbich TH, Popow C, Dobner M, et al. New-born infants with severe hyaline membrane disease: radiological evaluation during high frequency oscillatory versus conventional ventilation. Eur J Radiol. 1998;28:243-249. 6. HiFO Study Group. Randomized study of high-frequency oscillatory ventilation in infants with severe respiratory distress syndrome. J Pediatr. 1993;122:609-619. 7. Boynton BR, Mannino FL, Davis RF, Kopotic RJ, Friederichsen G. Combined high-frequency oscillatory ventilation and intermittent mandatory ventilation in critically ill neonates. J Pediatr. 1984;105:297-303. 8. Gerstmann DR, Minton SD, Stoddard RA, et al. The Provo multicenter early high-frequency oscillatory ventilation trial: improved pulmonary and clinical outcome in respiratory distress syndrome. Pediatrics. 1996;98:1044-1057. 9. Clark RH, Gertsmann DR, Null DM, et al. Pulmonary interstitial emphysema treated with high frequency oscillatory ventilation. Crit Care Med. 1986;14:926-930.
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10. deLemos RA, Coalson JJ, deLemos JA, King RJ, Clark RH, Gertsmann DR. Rescue ventilation with high frequency oscillation in premature baboons with hyaline membrane disease. Pediatr Pulmonol. 1992:12;29-36. 11. Minton SD. High-frequency oscillation using an inspiratory:expiratory ratio strategy of 1:2 decreased the incidence of air leak syndrome in infants with severe respiratory distress syndrome. N Engl J Med. 1989;320:88-90. 12. Kinsella JP, Parker TA, Galan H, et al. Independent and combined effects of inhaled nitric oxide, liquid perfluorochemical, and high frequency oscillatory ventilation in premature lambs with respiratory distress syndrome. Am J Respir Crit Care Med. 1999;159:1220-1227 Prepared by: Ruben D Restrepo, MD, RRT, is assistant professor, Cardiopulmonary Care Sciences Department, Georgia State University and PICU therapist, Children’s Healthcare of Atlanta at Egleston, Atlanta; and Stephen Dickson, RRT, is a PICU therapist at Children’s Healthcare of Atlanta at Egleston. These case studies are for reference only. Each patient is unique and may require different care.
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