Role of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange Therapy in the Management of a Twin Pregnancy with H1N1 Infection in Early Acute Respiratory Distress Syndrome.

Pregnancy with H1N1 infection presenting with early acute respiratory distress syndrome (ARDS) is a challenging situation, where the life of both mother and fetus are jeopardized. Morbidity and mortality in such a clinical situation are not uncommon; it may result in hypoxemic acute respiratory failure in a pregnant patient, leading to mechanical ventilation and poorer outcomes in neonates due to prematurity. An interdisciplinary approach involving obstetricians, respiratory physicians, neonatologist, and anesthesiologist is mandatory for a good outcome. This case report highlights the management strategy of the parturient infected with H1N1 in early ARDS with the Transnasal Humidified Rapid-Insufflation Ventilatory Exchange therapy, which completely obviated the requirement of the invasive ventilation. Copyright:

INTRODUCTION

Pregnant women exposed with H1N1 virus during antenatal period fall under highly susceptible category for infection with this virus.[1] They develop complications such as acute respiratory distress syndrome (ARDS) with respiratory failure and require mechanical ventilation.[2] The mortality rate for this group of patients can be as high as 9% if they develop ARDS and are mechanically ventilated.[3] Deteriorating maternal health might demand termination of pregnancy. There is a definite need of multidisciplinary approach for such patients and requires management in a center with support of a respiratory physician, including the intensive care unit (ICU) for the mother and a good neonatology setup with neonatal ICU in view of the prematurity and fetal morbidity. Here, we present a case of H1N1 complicating the twin pregnancy with the favorable outcome for both mother and the child.

CASE REPORT

A, 29-year-old female at 33-week 5-day period of gestation, presented with fever, chills and nonproductive cough of 6 days, and breathlessness for 1 day. Fever was continuous high-grade (temperature – 103°F) and associated with chills and rigor but with no evening rise or weight loss. Cough was dry nonproductive and associated with flu-like symptoms such as running nose, sore throat, and postnasal drip. The onset of breathlessness was sudden, which gradually progressed to the severity of being symptomatic at rest and aggravating even with mild exertion over a period of 24 h. Associated symptoms such as malaise, body ache, lethargy, and weakness prevailed. Clinical evaluation revealed tachycardia (pulse, 108/min, tachypnea (respiratory rate [RR] 26 per min), blood pressure 140/92 mmHg, and SPO2 of 90%–92% at room air and 98% with oxygen supplementation. Auscultation revealed bilateral crackles present all over the lung fields, which were more conspicuous in the infrascapular areas bilaterally. X-ray chest revealed bilateral nonhomogeneous opacity [Figure 1]. The patient was immediately admitted to respiratory ICU with suspicion of viral pneumonia with ARDS. The National Institute of Virology reports confirmed H1N1 infection. She was immediately started on tablet oseltamivir 75 mg BD, tablet azithromycin 500 mg TDS, and paracetamol 15 mg.kg-1 TDS for the fever. Urgent consultation was sought with obstetrician for termination of pregnancy at the completion of 34 weeks. Steroid prophylaxis was administered for fetal lung maturity. The patient was admitted in respiratory ICU and was placed on Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) therapy (Airvo™ 2, Fisher and Paykel Healthcare) using air/oxygen blender with humidifier set at the flow rate between 20 and 30 L.min-1 along with hemodynamic monitoring for the next 48 h [Figure 2]. The high-risk consent was taken for the surgery with the risks explained for the probability of the mechanical ventilation and adverse fetal outcome.

Figure 1

Nonhomogenous opacity bilaterally in both the lung fields

Figure 2

Set up for transnasal humidified rapid insufflation ventilatory exchange therapy (Airvo™ 2, Fisher and Paykel HealthCare)

On the day of surgery, all the health-care professionals were briefed about the case and were advised to wear personal protection as per the Centers for Disease Control and Prevention and World Health Organization recommendations. The patient was wheeled in the operation theater (OT) with her Airvo™ 2 device delivering continuous oxygen with high-flow rate (20–40 L.min-1), maintaining the oxygen saturation of 98% with RR of 24 per min with FiO2 of 0.5; arterial blood gas (ABG) analysis showed pH – 7.38, PCO2– 38 mmHg, PO2– 110 mmHg, and HCO3– 22 mmol.L-1. Standard monitoring ensued following the arrival in the OT, and the patient was prepared for spinal anesthesia. Noninvasive ventilator (NIV) (ResMed, ELISSE, Paris, France) was kept stand by and adequate preparations were done for the emergency intubation. Spinal anesthesia was administered in the sitting position, and about 2 ml of 0.5% bupivacaine heavy was given in the L3–L4 space. The patient was made supine with left tilt, and the head end was raised with the pillows. High-flow oxygen support (20–40 L.min-1) continued. Block level was confirmed till T4 level, and the surgery was started. Two live healthy female infants were born weighing around 2 kg each. Uterotonics were titrated to achieve adequate uterine contractions to prevent postpartum hemorrhage. Continuous intraoperative monitoring was within the normal limits. A total of 500 ml IV fluid (plasmalyte) was administered. RR remained at 24–26 per min throughout the surgery. Postoperatively, bilateral transversus abdominis plane block was given by the posterior approach for the postoperative pain relief. At postanesthesia care unit, the patient became breathless, and her RR increased to 40 per min, SpO2 – 90% with high-flow nasal therapy and was immediately placed on NIV (ResMed, Elisse, Paris, France) on NIV mode with the following settings, inspiratory positive airway pressure of 12 cm H20 and expiratory positive airway pressure of 6 cm H20 followed by injection furosemide 40 mg IV and was shifted to the ICU, her ABG was pH – 7.30, PCO2– 48 mmHg, PO2– 68 mmHg, and HCO3– 19 mmol.L-1. The patient improved gradually over 24 h, her RR reduced from 40 to 22 per min, and ABG improved with pH – 7.36, PCO2– 38 mmHg, PO2– 98mmHg, and HCO3– 20 mmol.L-1 and was weaned off the NIV successfully.

DISCUSSION

Physiological changes during pregnancy put the patient in a precarious condition and susceptible to the infections due to the immune modulation. Evidence shows critically ill pregnant women have higher morbidity and mortality in comparison to the nonpregnant women.[4] The spectrum in pregnant patients with H1N1 includes rapidly worsening lower respiratory tract infection, severe ARDS, and superadded bacterial infection progressing to the severity of sepsis, septic shock, and death.[4] ARDS following H1N1 infection results in higher mortality rates when compared with other causes of ARDS.[5] Timing of exposure to H1N1 during early trimester can affect the fetus adversely by causing the neural tube defects due to hyperthermia and resulting in the preterm delivery, neonatal seizures, neonatal mortality, and cerebral palsy in the survivors during exposure in the third trimester.[16] This clearly justifies the use of paracetamol along with the antiviral therapy.[6] Prompt antiviral therapy as was started in our case within the 48 h of the occurrence of symptoms is protective both for the mother and the fetus which led to improved neonatal outcome.[7]

Management of hypoxemic acute respiratory failure (ARF) begins with the oxygen supplementation with the face mask, and once the hypoxemia worsens NIV, or mechanical ventilation is indicated. Evidence suggests that mild-to-moderate hypoxemic ARF is amenable to the THRIVE therapy with its advantages of providing warm and humidified gases, which helps in reducing the work of breathing, improving the clearance of secretions with enhanced mucociliary function with better oxygenation, and reduced dead space ventilation.[8] Rello et al. in their cohort study could obviate the requirement of the endotracheal intubation in H1N1 patients with hypoxemic ARF in 20 patients treated with THRIVE.[9] Frat et al. concluded from their multi-centric open-label trial that the high-flow oxygen therapy has the maximum ventilator-free days when compared with NIV strategy and the standard oxygen supplementation group.[10] In hypoxemic ARF patients, inspiratory flow varies between 30 and >100 L.min-1, thereby resulting in the inconstancy in the required flow delivered by the conventional oxygen supplementation devices.[8]

Choice of anesthesia in a parturient with H1N1 depends on the severity of the ARDS. In mild-to-moderate severity, patients can be managed with neuraxial block with either high-flow nasal cannula oxygen therapy (THRIVE) or with NIV, completely avoiding the thoracoabdominal dyssynchrony. Parturient with H1N1 and severe ARDS needs to be managed with GA and controlled ventilation to optimize the oxygenation and ventilation.[268] Rush et al. in their multivariate model estimated the mortality in pregnant patients with ARDS who were mechanically ventilated in the range between 9% and 14%.[3] Deterioration in the clinical condition occurred in our case in the immediate postoperative period despite the fluid restriction intraoperatively which could be attributed to the autotransfusion of the blood following the relief of the aortocaval compression as well as due to uterine contractions postdelivery. NIV in our case helped in tiding over the crisis in the next few hours, when the patient's general condition improved and was shifted back on the THRIVE therapy.

CONCLUSION

A parturient with H1N1 infection presenting with the hypoxemic ARF in the third trimester poses a constant threat to both, mother and the fetus. A multidisciplinary approach with the closed loop functioning between obstetricians, neonatologist, respiratory physicians, and anesthesiologist is a cornerstone in the successful management of such critical patients. Management with THRIVE therapy in such high-risk pregnancies with hypoxemic ARF with early ARDS has paved the way for more research in similar clinical situations, where it could obviate the need of mechanical ventilation and can result in favorable outcomes.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patients understand that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.