211: Comparative Physiologic Effects of Noninvasive Assist-Control and Pressure Support Ventilation in Acute Hypercapnic Respiratory Failure

ICEM 2008 Scientific Abstract Program 4. This study shows that there is good negative correlation in between ETCO2 and patients presented with pulmonary disorder where the Pearson’s correlation coefficient of 0.336 and p value of 0.00(p⬍0.05). Conclusions: 1. There is strong correlation between ETCO2 and PaCO2 in non intubated acute breathlessness patient presented to ED HUSM and hence ETCO2 is applicable as a form of non invasive cardiopulmonary monitoring in non intubated acute breathlessness patient. 2. This study shows that ETCO2 can be used to predict PaCO2 level where the difference between PaCO2 and ETCO2 is between 2 to 6 mmHg especially in the case of pure acidosis and hypocapnia. The usage of ETCO2 to predict PaCO2 should be done with caution especially in cases that involve pulmonary disorder.

211

Comparative Physiologic Effects of Noninvasive Assist-Control and Pressure Support Ventilation in Acute Hypercapnic Respiratory Failure

Afasanwo BK, Kodjovi M, Jinadu NA/University of Ibadan, Ibadan, Nigeria

Study Objectives: To compare the effects of noninvasive assist-control ventilation (ACV) and pressure support ventilation (PSV) by nasal mask on respiratory physiologic parameters and comfort in acute hypercapnic respiratory failure (AHRF). Methods: A prospective randomized study. Setting: A medical ICU. Patients and Interventions: Fifteen patients with COPD and AHRF were consecutively and randomly assigned to two noninvasive ventilation (NIV) sequences with ACV and PSV mode, spontaneous breathing (SB) via nasal mask being used as control. ACV and PSV settings were always subsequently adjusted according to patient’s tolerance and air leaks. Fraction of inspired oxygen did not change between the sequences. Results: ACV and PSV mode strongly decreased the inspiratory effort in comparison with SB. The total inspiratory work of breathing (WOBinsp) expressed as WOBinsp/tidal volume (VT) and WOBinsp/respiratory rate (RR), the pressure time product (PTP), and esophageal pressure variations (deltaPes) were the most discriminant parameters (p⬍0.001). ACV most reduced WOBinsp/VT (p⬍0.05), deltaPes (p⬍0.05), and PTP (0.01) compared with PSV mode. The surface diaphragmatic electromyogram activity was also decreased ⬎32% as compared with control values (p⬍0.01), with no difference between the two modes. Simultaneously, NIV significantly improved breathing pattern (p⬍0.01) with no difference between ACV and PSV for VT, RR, minute ventilation, and total cycle duration. As compared to SB, respiratory acidosis was similarly improved by both modes. The respiratory comfort assessed by visual analog scale was less with ACV (57.23⫹/⫺30.12 mm) than with SB (75.15⫹/⫺18.25 mm) (p⬍0.05) and PSV mode (81.62⫹/⫺25.2 mm) (p⬍0.01) in our patients. Conclusion: During NIV for AHRF using settings adapted to patient’s clinical tolerance and mask air leaks, both ACV and PSV mode provide respiratory muscle rest and similarly improve breathing pattern and gas exchange. However, these physiologic effects are achieved with a lower inspiratory workload but at the expense of a higher respiratory discomfort with ACV than with PSV mode.

212

Ventilatory Support in Intensive Medical Care Unit of a Government Hospital in India: An Etiological and Prognostic Profile

Srinivas SK, Mathur M, Rajendran C, Rajasekaran D, Subramanian PT/Madras Medical College, Chennai, India

Study Objectives: 1. To study the etiological profile of the patients requiring ventilatory support in intensive medical care unit (IMCU) of a government hospital in a developing country like India. 2. To find out the duration of ventilatory support required by them and to analyze their prognosis. Methods: Settings: IMCU, Institute of Internal medicine, Madras medical college, Chennai. Study design: Retrospective study. Period: January 2006 to December 2006. Study participants:Total of 180 patients (males m) 122,females (f) 58) who got admitted in IMCU for ventilatory support. Exclusion criteria: 1. patients not requiring ventilatory care. 2. Surgical and trauma patients. Parameters analyzed: 1. Age 2. Sex. 3. Diagnosis

Volume , .  : April 

4. Duration of ventilatory support. 5. Outcome in terms of mortality. Statistical Analysis: Simple descriptive statistics. Results: Out of 180 patients analyzed, the most common cause for ventilatory support was organo phosphorus compound (OPC) poisoning which was seen in 21.1% of patients (m 84.2%, f 15.8%). This was followed by Guillain Barre syndrome (GBS) in 11.1% (m 50%, f 50%), status epilepticus in 6.6% (m 58.3%,f 63.6%), chronic kidney disease (CKD) in 6.6% (m 41.7%, f 58.3%), hanging in 6.1% (m 70%,f 30%), acute exacerbation of chronic obstructive pulmonary disease (COPD) in 5.5% (m 70%,f 30%) and snake bite in 4.4% (m 75%, f 25%). Other causes were due to poisoning by sedatives (3.3%), acids (1.1%), phenol (0.5%), carbamate (0.5%), alcohol (1.1%) and cyanide (0.5%), cerebrovascular accidents (CVA) (6%), acute exacerbation of bronchial asthma (2.2%), acute respiratory distress syndrome (ARDS) (2.2%), myasthenia gravis(2.7%), septicemia (1.6%), acute pulmonary edema (1.6%), hepatic (2.2%) and metabolic encephalopathy (1.1%), and acute renal failure (ARF)(1.6%). Rare causes included pneumonias, hypokalemic periodic paralysis, miliary tuberculosis, acute lymphoblastic leukemia, chronic inflammatory demyelinating polyneuropathy, interstitial lung disease and viral encephalitis. The condition requiring maximum days of ventilatory support was hanging which required an average of 8.5 days. This was followed by OPC poisoning (8.2 days), GBS (7.1days), acute exacerbation of COPD (6.6 days), snake bite (6.4 days), status epilepticus (4.8 days) and CKD (3.1 days). Out of total 180 patients mortality was observed in 116 patients, i.e., 64.4% (m 70.6%, f 29.4%). The conditions which had poorest prognosis were septicemia, hepatic encephalopathy, CVA (both intracerebral hemorrhage and infarct) and ARF which had 100% mortality. This was followed by acute exacerbation of COPD (80%), ARDS (75%), CKD (75%), status epilepticus (75%), hanging (72.7%), acute pulmonary edema (66.6%), OPC poisoning (60.5%), GBS (50%) and snake bite (25%). Better prognosis was seen in myasthenia gravis and sedative poisoning which had mortality rate of 20 and 16% respectively. Conclusion: The most common conditions requiring ventilatory support in a government hospital setup in India were OPC and hanging which were secondary to suicidal attempts.They were followed by GBS, acute exacerbation of COPD, status epilepticus and snake bite. These were also the conditions requiring maximum days of ventilatory support. High mortality was associated with septicemia, hepatic encephalopathy, CVA, ARF, acute exacerbation of COPD, ARDS, CKD, status epilepticus, hanging, acute pulmonary edema, OPC poisoning and GBS. Poor prognosis associated with these conditions could be due to late presentation to the tertiary care hospital like the one included in the study. Improvement in critical care facilities in primary and secondary health care level could lead to reduction in mortality.

213

Demographics of Inpatient Admissions in Mwami, Zambia

Heinrich SA, Lin JY/University of Illinois, Chicago, IL

Study Objectives: For the past 3 academic years, residents from The University of Illinois at Chicago have taken elective months to work in rural Zambia at the Mwami Adventist Hospital. The hospital has 210 inpatient beds and admits patients from the outpatient clinic which sees close to 60 patients per day. No study examining the demographics and illnesses of patients admitted to the hospital has been published. Conclusions from this data could help the hospital and physicians better allocate scarce resources for patient care. Methods: All documented inpatient encounters at Mwami Adventist Hospital over a four week span from June to July 2007 were reviewed for patient demographics, length of stay, discharge diagnosis, mortality, and referral or transfer. Discharge diagnosis was classified into skin and soft tissue complaints, cardiovascular disorders, musculoskeletal complaints, obstetrics and gynecology, neurologic complaints, malnutrition, malignancy, infections and other. Infections were further subclassified into malaria, HIV/AIDS, respiratory, genitourinary, gastrointestinal, central nervous system and ear, nose and throat. Patients with multiple diagnoses had them entered individually. Females admitted to the hospital for spontaneous vaginal deliveries were not included in hospital records and thus not in this review. Results: There were 177 patient admissions encompassing 172 distinct patients. The patients were 52% female and the mean age was 25.9 ⫾ 23.0 years with patients ranging in age from 10 days to 93 years. 50% of the total visits were accounted for by patients 18 years and younger while 42% of the patients were 19-65 and 8% were above 65 years of age. The average length of stay was 5.4 ⫾ 4.8 days. Infections made

Annals of Emergency Medicine 535