Critically Ill Patients with H1N1 Pneumonia: Two Year Experience in a Tertiary Level Indian ICU

  • Prachee Sathe Department of Critical Care Medicine, Ruby Hall Clinic, 40, Sassoon Road, Pune, Maharashtra, India.
  • Arun Kumar Parathody Ruby Hall Clinic
  • Rakesh Tukaram Borse Department of Critical Care Medicine, Ruby Hall Clinic, 40, Sassoon Road, Pune, Maharashtra, India.
Keywords: H1N1, Mortality, Length of Stay, Predictors, Intensive Care


Purpose: To learn about the clinical profile, outcome and quality of life and factors influencing these, in critically ill patients with H1N1 pneumonia.

Methods: Retrospective analysis of case files and phone interview of 88patients with confirmed H1N1 pneumonia.

Results: Out of 88 patients, 51 were males. Mean age was 48.23 [± 13.03]. 39 [44.31%] were in the 31-50 years age group and 37 [42.04%] were in the 51-70 age group. Diabetes [n=16] and Hypertension [n=20] were the most common comorbidities. Majority of the patients presented with cough [n=87], breathlessness [n=85] and fever [n=84]. 43 patients had severe ARDS on admission. Mean APACHE II score was 9.6 [± 5.4] Mean SOFA scores 4.99 [± 2.6]. Mean Murray score was 2.37 [± 0.76]. 46 patients [52%] survived. Factors associated with mortality were APACHE score [p=0.00], SOFA score [p=0.00] Murray score, severe ARDS [p=0.00], requirement of vasopressor support [p=0.00] or renal replacement therapy [p=0.00] and incidence of VAP [p=0.039]. Diabetes had a protective effect [p=0.04], as had non-invasive ventilation [p=0.00]. Murray score [p=0.000, SOFA score [p=0.036], initiation of mechanical ventilation [p=0.003] and incidence of VAP [p=0.00] was associated with increased length of stay among the survivors.

Conclusion: Higher lung specific severity scores, severe ARDS, secondary organ failure and VAP were associated with increased mortality. Among survivors, higher Murray and SOFA scores, mechanical ventilation and vasopressor use entailed a longer ICU stay.

How to cite this article:
Sathe P, Parathody AK, Borse RT. Critically Ill Patients with H1N1 Pneumonia: Two Year Experience in a Tertiary Level Indian ICU. J Commun Dis. 2021;53(3):89-95.




Centers for Disease Control and Prevention (CDC). Outbreak of swine-origin influenza A (H1N1) virus

infection-Mexico. MMWR Morb Mortal Wkly. Rep. 2009 May;58:467-70. [PubMed] [Google Scholar]

Pandemic Influenza A H1N1. Clinical management Protocol and Infection Control Guidelines. Director

General of Health Services. Human swine influenza: A pandemic threat. Government of India: CD Alert, India.

;12:1-8. Available from:

Anand R, Gupta A, Gupta A, Wardhawan S, Bhadoria P. Management of swine-flu patients in the intensive care

unit: Our experience. J Anaesthesiol Clin Pharmacol. 2012 Jan-Mar;28(1):51-5. [PubMed] [Google Scholar]

Chawla R, Kansal S, Chauhan M, Jain A, Jibhkate BN. Predictors of mortality and length of stay in hospitalized

cases of 2009 influenza A (H1N1): Experiences of a tertiary care center. Indian J Crit Care Med. 2013 Sep-

Oct;17(5):275-82. [PubMed] [Google Scholar]

Patel M, Dennis A, Flutter C, Khan Z. Pandemic (H1N1) 2009 influenza. Br J Anaesth. 2010 Feb;104:128-42.

[PubMed] [Google Scholar]

Zarychanski R, Stuart TL, Kumar A, Doucette S, Elliott L, Kettner J, Plummer F. Correlates of severe disease

in patients with 2009 pandemic influenza (H1N1) virus infection. CMAJ. 2010 Feb;182:257-64. [PubMed]

[Google Scholar]

Louie JK, Acosta M, Winter K, Jean C, Gavali S, Schechter R, Vugia D, Harriman K, Matyas B, Glaser CA, Samuel

MC, Rosenberg J, Talarico J, Hatch D; California Pandemic (H1N1) Working Group. Factors associated

with death or hospitalization due to pandemic 2009 influenza A (H1N1) infection in California. JAMA. 2009

Nov;302(17):1896-902. [PubMed] [Google Scholar]

Kumar A, Zarychanski R, Pinto R, Cook DJ, Marshall J, Lacroix J, Stelfox T, Bagshaw S, Choong K, Lamontagne

F, Turgeon AF, Lapinsky S, Ahern SP, Smith O, Siddiqui F, Jouvet P, Khwaja K, McIntyre L, Menon K, Hutchison J,

Hornstein D, Joffe A, Lauzier F, Singh J, Karachi T, Wiebe K, Olafson K, Ramsey C, Sharma S, Dodek P, Meade M,

Hall R, Fowler RA; Canadian Critical Care Trials Group H1N1 Collaborative. Critically ill patients with 2009

influenza A(H1N1) infection in Canada. JAMA. 2009 Nov;302:1872-9. [PubMed] [Google Scholar]

Thompson WW, Shay DK, Weintraub E, Brammer L, Bridges CB, Cox NJ, Fukuda K. Influenza associated

hospitalizations in the United States. JAMA. 2004 Sep;292:1333-40. [PubMed] [Google Scholar]

Jain S, Kamimoto L, Bramley AM, Schmitz AM, Benoit SR, Louie J, Sugerman DE, Druckenmiller JK, Ritger

KA, Chugh R, Jasuja S, Deutscher M, Chen S, Walker JD, Duchin JS, Lett S, Soliva S, Wells EV, Swerdlow D,

Uyeki TM, Fiore AE, Olsen SJ, Fry AM, Bridges CB, Finelli L; 2009 Pandemic Influenza A (H1N1) Virus

Hospitalizations Investigation Team. Hospitalized patients with 2009 H1N1 influenza in the United States,

April-June 2009. N Engl J Med. 2009 Nov;361(20):1935-44. [PubMed] [Google Scholar]

Hancock K, Veguilla V, Lu X, Zhong W, Butler EN, Sun H, Liu F, Dong L, DeVos JR, Gargiullo PM, Brammer TL,

Cox NJ, Tumpey TM, Katz JM. Crossreactive antibody responses to the 2009 pandemic H1N1 influenza virus.

N Engl J Med. 2009 Nov;361(20):1945-52. [PubMed] [Google Scholar]

Moss M, Guidot DM, Steinberg KP, Duhon GF, Treece P, Wolken R, Hudson LD. Parsons PE: Diabetic patients

have a decreased incidence of acute respiratory distress syndrome. Crit Care Med. 2000 Jul;28(7):2187-92.

[PubMed] [Google Scholar]

Chudasama RK, Verma PB, Amin CD, Gohel B, Savariya D, Ninama R. Correlates of severe disease in patients

admitted with 2009 pandemic influenza A (H1N1) infection in Saurashtra region, India. Indian J Crit Care

Med. 2010 Jul;14(3):113-20. [PubMed] [Google Scholar] 14. Chacko J, Gagan B, Ashok E, Radha M, Hemanth HV.

Critically ill patients with 2009 H1N1 infection in an Indian ICU. Indian J Crit Care Med. 2010 Apr;14(2):77-

[PubMed] [Google Scholar]

Perez-Padilla R, de la Rosa-Zamboni D, Ponce de Leon S, Hernandez M, Quiñones-Falconi F, Bautista

E, Ramirez-Venegas A, Rojas-Serrano J, Ormsby CE, Corrales A, Higuera A, Mondragon E, Cordova-Villalobos

JA, INER Working Group on Influenza. Pneumonia and respiratory failure from swine-origin influenza A

(H1N1) in Mexico. N Engl J Med. 2009 Aug;361(7):680-9. [PubMed] [Google Scholar]

Chien YS, Su CP, Tsai HT, Huang AS, Lien CE, Hung MN, Chuang JH, Kuo HS, Chang SC. Predictors and outcomes of respiratory failure among hospitalized pneumonia patients with 2009 H1N1 influenza in Taiwan. J Infect. 2010 Feb;60(2):168-74. [PubMed] [Google Scholar]

Knaus WA, Draper EA, Wagner DP, Zimmerman JE. APACHE II: a severity of disease classification system.

Crit Care Med. 1985 Oct;13(10):818-29. [PubMed] [Google Scholar]

Ferreira FL, Bota DP, Bross A, Melot C, Vincent JL. Serial evaluation of the SOFA score to predict outcome in

critically ill patients. JAMA. 2001 October;286:1754e8. [PubMed] [Google Scholar]

Murray JF, Matthay MA, Luce JM, Flick MR. An expanded definition of the adult respiratory distress syndrome.

Am Rev Respir Dis. 1988 Sep;138(3):720-3. [PubMed] [Google Scholar]

Peek GJ, Mugford M, Tiruvoipati R, Wilson A, Allen E, Thalanany MM, Hibbert CL, Truesdale A, Clemens F,Cooper N, Firmin RK, Elbourne D. Efficacy and economic assessment of conventional ventilatory support versus

extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised

controlled trial. Lancet. 2009 Oct;374(9698):1351-63. [PubMed] [Google Scholar]

Xi X, Xu Y, Jiang L, Li A, Duan J, Du B, Chinese Critical Care Clinical Trial Group. Hospitalized adult patients

with 2009 influenza A(H1N1) in Beijing, China: risk factors for hospital mortality. BMC Infect Dis. 2010

Aug;10:256. [PubMed] [Google Scholar]

Golabchi A, Sarrafzadegan N. What Every Cardiologist Should Know about H1N1? ARYA Atheroscler.

;6(3):118-21. [PubMed] [Google Scholar]

Jeyanathan T, Overgaard C, McGeer A. Cardiac complications of influenza infection in 3 adults. CMAJ.

Apr;185(7):581-4. [PubMed] [Google Scholar]

Trimarchi H, Greloni G, Campolo-Girard V, Giannasi S, Pomeranz V, San-Roman E, Lombi F, Barcan L, Forrester

M, Algranati S, Iriarte R, Rosa-Diez G. H1N1 infection and the kidney in critically ill patients. J Nephrol. 2010

Nov-Dec;23:725-31. [PubMed] [Google Scholar]

Patel J, Khadtare A, Parmar I. Study of acute kidney injury in H1N1 patients (year 2015). Gujarat Med J.


Liem NT, Tung CV, Hien ND, Hien TT, Chau NQ, Long HT, Hien NT, Mai le Q, Taylor WR, Wertheim H, Farrar J,

Khang DD, Horby P. Clinical features of human influenza A (H5N1) infection in Vietnam: 2004-2006. Clin Infect

Dis. 2009 Jun;48(12):1639-46. [PubMed] [Google Scholar]

Álvarez-Lerma F, Marín-Corral J, Vilà C, Masclans JR, Loeches IM, Barbadillo S, González de Molina FJ,

Rodríguez A, H1N1 GETGAG/SEMICYUC Study Group. Characteristics of patients with hospital-acquired

influenza A (H1N1)pdm09 virus admitted to the intensive care unit. J Hosp Infect. 2017 Feb;95:200-6.

[PubMed] [Google Scholar]

Rello J, Rodríguez A, Ibañez P, Socias L, Cebrian J, Marques A, Guerrero J, Ruiz-Santana S, Marquez E,

Del Nogal-Saez F, Alvarez-Lerma F, Martínez S, Ferrer M, Avellanas M, Granada R, Maraví-Poma E, Albert P,

Sierra R, Vidaur L, Ortiz P, Prieto del Portillo I, Galván B, León-Gil C; H1N1 SEMICYUC Working Group. Intensive

care adult patients with severe respiratory failure caused by influenza a (H1N1)v in Spain. Crit Care.

;13(5):R148. [PubMed] [Google Scholar]

Sahoo JN, Poddar B, Azim A, Singh RK, Gurjar M, Baronia AK. Pandemic (H1N1) 2009 influen za: Experience from a critical care unit in India. Indian J Crit Care Med. 2010 July;14(3):156-9. [PubMed] [Google Scholar]

Lansbury LE, Smith S, Beyer W, Karamehic E, Pasic-Juhas E, Sikira H, Mateus A, Oshitani H, Zhao H, Beck CR,

Nguyen-Van-Tam JS. Effectiveness of 2009 pandemic influenza A(H1N1) vaccines: a systematic review and

meta-analysis. Vaccine. 2017 Apr;35:1996-2006. [PubMed] [Google Scholar]

Lee RU, Phillips CJ, Faix DJ. Seasonal influenza vaccine impact on pandemic H1N1 vaccine efficacy. Clin Infect

Dis. 2019 May;68(11):1839-46. [PubMed] [Google Scholar]