Capnography

Primary endpoint: To describe the Bland-Altman agreement of end-tidal CO₂ (EtCO₂) measurements between MARIETM airway adapter (Oxlantic Medical AB) and a standard capnography, Getinge Flow-i, in intubated patients.

This prospective, randomized controlled study aims to investigate whether transnasal microstream end-tidal carbon dioxide (EtCO₂) monitoring in the post-anesthesia care unit (PACU) reduces the incidence of postoperative hypoxemia in elderly patients (65-80 years, ASA I-III, BMI 18-30 kg/m²) undergoing elective laparoscopic surgery under general anesthesia with endotracheal intubation. A total of 324 patients will be randomized 1:1 to either the control group (standard SpO₂ monitoring and clinical observation with oxygen delivery at 2 L/min via sampling line) or the experimental group (same oxygen delivery plus continuous real-time transnasal microstream EtCO₂ monitoring). The primary outcome is the incidence of hypoxemia (SpO₂ \< 90% for \>15 seconds) after extubation in the PACU. Secondary outcomes include severe hypoxemia (SpO₂ \< 85%), lowest SpO₂ during PACU stay, vital signs at specified time points, PACU length of stay, and other adverse events. Statistical analysis will use chi-square or Fisher's exact test for the primary outcome, with a sample size calculated to detect a reduction in hypoxemia from 33% (control) to 18% (experimental group) (α=0.05, power=80%, plus 20% dropout).

In this study, we want to find out if measuring carbon dioxide from a patient's breath (end-tidal CO₂ or ETCO₂) can reliably reflect changes in blood carbon dioxide levels (arterial CO₂ or PaCO₂) during lung surgery. Instead of just looking at individual values, we are specifically investigating whether ETCO₂ and PaCO₂ rise and fall in the same direction over time. During lung surgery, patients often need "one-lung ventilation," where only one lung is used for breathing while the other is deflated to help the surgeon. This can cause carbon dioxide levels in the blood to change, which are typically monitored by taking blood samples. If ETCO₂ trends closely follow PaCO₂ trends, doctors may not need to take as many blood samples. Patients in this study will already have a small tube in an artery for monitoring blood pressure. Whenever a blood test is taken, we will compare the blood CO₂ level with the ETCO₂ reading at that moment. We will also track heart rate, blood pressure, and body temperature. By comparing these measurements, we hope to learn whether ETCO₂ reliably follows the same trends as PaCO₂, making it a useful tool for monitoring carbon dioxide levels in lung surgery with fewer blood tests.

This study aims to detect the effect of different O2 flow rates on end tidal carbon dioxide level in patients scheduled for minor gynaecological procedures under deep sedation using laryngeal mask airway. * Primary outcome was measuring end tidal carbon dioxide ( EtCO2 ) non invasively by laryngeal mask all through the procedure. * Secondary outcomes included peripheral O2 saturation, hemodynamics, time to recovery, total propofol dose, patients' satisfaction, sedation score, and complications.

A prospective observational diagnostic study will be conducted to assess the sensitivity and specificity of using capnography in detecting the correct placement of nasogastric tubes using the reference standards of radiography and measurement of aspirates for pH value.