Objective: We try to answer the question of '' how much will (co2) of blood change if we keep the amount of fresh gases constant" the subject of the present study on patients in Tajrish hospital in winter 1998.Methods: This research was done on 80 ADULTS in the age group of 15-65. Who was under goung a surgical operation of lung. This was clinical trial using double blind sequential method subjects in control group were giner inspirations (12/min) and 12 times in the first 30 minutes for those in test group and in both groups the PACO2 of blood was measured by the AVL SYSTEM during the first 30 and 60 minutes. The amount of drug used before ANESTHESIA and also the amount of anesthetic gases has been equal in both groups.Findings: The research outcome has shown that the amount of PACO2 was not changed at all in control group where as it has increased among the experimental subjects from 28.74±3.38 in the first half hour to 34.32 ±3.65 in the first hour. While paired t test showed that this 20% increase can be noticeable, statistics (p<0.001) and the changes of PACO2 in both groups also revealed to be clear and meaningful (p<0.001).Conclusion: The results have shown that increased respiratory rate increases the level of PACO2, although such increments would be considered normal.  

Background: End-tidal CO2 has a linear correlation with arterial pressure of CO2 in ADULTS. Such relationship in critically ill pediatric patients is conflicting. We have studied this correlation in intubated patients of Mofid Pediatric Hospital, Tehran, Iran.Materials and methods: From 38 mechanically ventilated critically ill, intubated patients 68 pair samples of PACO2- PETCP2 were gathered. We used side stream capnograph before arterial sampling. This study were conducted from March 2006 until October 2007 in pediatric intensive care unit of Mofid Hospital.Results: Patients were 2.2±3 year old and 56% of them were girls. They were admitted due to neurologic, respiratory, hematology, cardiology or other causes. PETCO2 showed a strong correlation with PACO2. Linear regression analysis depicted following outcome: PETCO2=0.7 PACO2 (95% confidence interval: 0.56-0.79) +3.7 (95% confidence interval: 0.5-7.9) Those patients with a better respiratory condition (SpO2>85%) had a PACO2 - PETCO2 difference of 4±2 while in poor circumstances (SpO2<85%) this figure was 11±7.Conclusion: We recommende using capnograph for monitoring ventilation of intubated pediatric patients in intensive care units. Estimation of arterial CO2 pressure according to end-tidal CO2 depends on the pulmonary function. As the respiratory condition deteriorates PACO2-PETCO2 difference enlarges but the linear correlation remains.

Background: It is necessary to determine the value of PaO2 and PACO2 in COPD patients for diagnosis the severity of chronic bronchitis diseases and their separation from other diseases.For the diagnosis of COPD diseases and their separation from other diseases and for having a criterion for treatment with oxygen, we need to know the amount of Pao2 and PACO2 in patients; ABG is an invasive and difficult procedure.Materials and Methods: This cross sectional study was carried out on 118 consecutive patients with chronic bronchitis referring to Afshar hospital in Yazd in order to determine the correlation between spirometry FEV1 and ABG parameters.Results: The study population included 82 (69.5%) males and 36(30.5%) females with the mean age of 71.6±9 years. The mean FEV1 (% pred.) was 42.88±15.12, mean PaO2 was 55.31±13.51 mmHg and mean PACO2 was 51.64±10.56 mmHg. FEV1 was positively correlated with PaO2 (r=0.418, p<0.0001) and inversely correlated with PACO2 (r= -0.533, p<0.0001).Conclusion: One could establish a reliable equation indicating the correlation between FEV1 and PaO2 as well as PACO2 in patient with chronic bronchitis.

Introduction: Inhalation induction is a common method in pediatrics ANESTHESIA . There is not suitable clincial guide for assessmen depth of ANESTHESIA before intubation, in this study adequacy of Jaw thrust as a guide for this assessement was evaluated.Methods: In a clinical trial study 90 pediatric patient, ASA1 & 2, six month to 5 year old age, were divided in case and control groups. Inhalation inductions were done by 4% Halothane, 4lit/min O2 and 4Lit/min N2o under spontaneous ventilation. In case and control groups, Jaw thrust and ordinary methods were utilized respectively for assessment of depth of ANESTHESIA befor intubations. Changes in HR, SpO2, end tidal of halothane and duration of induction, duration of laryngoscopy, reactions to intubations and complications were measured and then analyzed by t - test and Chi squar statistical tests.Results: Duration and complications of larynogscopy were greater in case than control group. Conclusion: Jaw thrust alone is not a good clinical test assessment of depth of ANESTHESIA before intubations in inhalation ANESTHESIA. Probaly one and half to two minutes after negative respones to jaw thrust is a suitable time for intubations in pediatrics inhalation ANESTHESIA .

Capnography is one of the most important monitoring that is recommended by American Society for Testing and Material in 1998 (ASTM98) for every patient under ANESTHESIA.Usually sampling of expired gas in capnography commonly obtained from side or mid stream. Badgwell and et al recommended that sampling of expired gas for Capnography for patient under one year should be taken from distal end of endotracheal tube.In this study to determine accuracy of ventilation with modified Jackson Rees SYSTEM, we studied 622 infants and children who were ventilated with this SYSTEM. Expired gas for CO2 monitoring sampled at distal and proximal end of endotracheal tube and the arterial Pco2 (PACO2) simultaneously measured.In this paper we studied the accuracy of ventilation with modified Jackson Rees SYSTEM in 62 infants and children. We sampled the expired gas for CO2 analysis from both proximal and distal of the endotracheal tube and measured PACO2 simultaneously.In our experience we found that PETCO2-d (distal end - tidal PCO2) was close to PACO2, but PETCO2-p(proximal end - tidal PCO2) was insignificantly greater than PACO2 especialy in infant who were less than 10kg. As we did not find any significant difference between measurement of PETCO2-d (distal end tidal PCO2) and PETCO2-p (proximal end tidal PC02), we suggest to measure PETC02-p instead of PETC02-d, in any infant less than 10kg and children weighting more than 10kg who Ventilated by modified Jackson Rees SYSTEM.

Background: The diagnosis of pulmonary embolism (PE) because of nonspecific clinical presentation remains as a challenge for emergency physicians. Arterial to end‑, tidal partial pressure of carbon dioxide (P(a‑, Et)CO2 ) gradient may be useful in the evaluation of PE. This aimed to define the diagnostic role of P(a‑, Et)CO2 gradient by sidestream capnography, as a noninvasive method, and D‑, dimer in patients with PE. Materials and Methods: Two hundred and three patients with chest pain or dyspnea who attend the hospital emergency ward were enrolled over a study period at a single academic center. PE was confirmed by multidetector computed tomography (MDCT) scans. PACO2, EtCO2, and D‑, dimer were measured within 24 h of MDCT by capnograph. Results: The combination of P(a‑, Et)CO2 gradient (cutoff >9. 2 ng/ml) and D‑, dimer (cutoff >3011 ng/ml) with sensitivity and specificity of 30. 2% and 87. 2% showed a significant diagnostic value in detecting PE (area under the curve = 0. 577, P = 0. 045) but not alone (P > 0. 05). Conclusion: As the results show, the combination of P(a‑, Et)CO2 gradient and D‑, dimer can show an acceptable diagnostic value in detecting PE, although it suggests further research on evaluating the diagnostic value of P(a‑, Et)CO2 gradient and combining it with other diagnostic criteria to achieve a definite and generalizable result.