Autoclaving Sterilization: Key Parameters
Autoclaving is a widely used method for sterilization, employing steam under pressure to effectively eliminate microorganisms. This process relies on specific temperature, pressure, and time combinations to ensure complete sterilization.
Standard Autoclave Conditions
The effectiveness of autoclaving depends on maintaining adequate conditions. Common parameters used in autoclaves are:
- Temperature: High temperatures achieved by saturated steam.
- Pressure: Increases the boiling point of water, allowing higher steam temperatures.
- Time: Duration required for steam to penetrate and kill all microorganisms.
Based on standard laboratory and medical practices, the typical conditions are often cited as:
| Pressure | Temperature | Time |
| 15 lb pressure (gauge) | Approximately $121^\circ\text{C}$ to $124^\circ\text{C}$ (often simplified to $120^\circ\text{C}$ in options) | 15-20 minutes |
Determining Correct Autoclaving Settings
Analyzing the given options against standard autoclaving protocols:
- Option 1 ($100^\circ\text{C}$) is insufficient for effective sterilization; it's the boiling point at standard pressure.
- Option 2 (15 lb pressure, $120^\circ\text{C}$ temperature, 15 minutes) closely matches the commonly accepted standard conditions for effective autoclaving.
- Options 3 and 4 involve higher pressures and longer times but are not the typical baseline standard, although variations exist for specific applications. The $120^\circ\text{C}$ at 15 lb is the most recognized standard.
Therefore, the combination of 15 lb pressure, $120^\circ\text{C}$ temperature, and 15 minutes represents the standard and most effective condition among the choices for autoclaving.
Important Questions from Pre-operative & Post-operative Care
- A surgeon is about to start a laparoscopic procedure on a patient. The floor nurse asks the surgeon about the identity of the patient, site of the procedure to be performed and any anticipated critical events during the surgery. These questions are a part of the
- Perioperative benefit from transfusion is with a haemoglobin level of
- A 60 year old lady underwent total abdominal hysterectomy. On the 3rd post operative day she suddenly became breathless while returning from washroom. Her blood pressure recorded was $80/50$ mm of Hg. The most probable diagnosis is
- Perioperative benefit from transfusion is with a haemoglobin level of
- A 20 year old patient underwent open hernia surgery four days back. He is running fever for the last one day and on local examination the operated site was wet with pus and surrounding redness and edema. The appropriate management would be:
