How to distinguish respiratory acidosis, metabolic acidosis, respiratory alkalosis and metabolic alkalosis?😕😕😕

Arterial blood gas analysis is the main diagnostic method for distinguishing
respiratory acidosis, metabolic acidosis, respiratory alkalosis and metabolic alkalosis. Arterial blood gas analysis can be simply divided into three steps. The first step is to determine whether the patient has acidosis or alkalosis. The second step is to determine whether the acidosis or alkalosis is respiratory or metabolic. The third step is to determine whether the patient has respiratory acidosis or respiratory alkalosis due to respiratory factors alone or metabolic factors.

The specific method of arterial blood gas analysis is as follows:

Step 1: Check the patient's pH. A normal pH is 7.4 ± 0.05. If the patient is acidotic, the pH should be ≤ 7.35. If the patient is alkalotic, the pH should be ≥ 7.45.

Step 2:  Observe the direction of changes in the patient's pH and PCO₂. If the acidosis or alkalosis is metabolic, pH and PCO₂ will change in the same direction (an increase in pH will increase PCO₂, or a decrease in pH will decrease PCO₂). If the acidosis or alkalosis is respiratory, pH and PCO₂  will change in opposite directions.

Step 3: If respiratory acidosis or alkalosis is present, observe the ratio of changes in the patient's pH to PCO₂. A normal PCO₂ is 40 ± 5 mmHg. In simple respiratory acidosis or alkalosis, for every 10 mmHg change in PCO₂, the pH value changes in the opposite direction by 0.08 ± 0.02. For example, if a patient has a PCO₂ of 40 mmHg and a pH of 7.4, a decrease in their PCO₂ by 10 mmHg to 30 mmHg would increase their pH by 0.08 to 7.48. A decrease in their PCO₂ by 20 mmHg to 60 mmHg would decrease their pH by 0.16 to 7.24.

If the changes in pH and PCO₂ do not conform to this ratio, it indicates that the patient also has a second factor (metabolic factor). In this case, the medical staff should compare the patient's theoretical pH value with the actual pH value. If the actual pH value is lower than the theoretical pH value, it indicates that metabolic acidosis is also present. Conversely, if the actual pH value is higher than the theoretical pH value, it indicates that metabolic alkalosis is also present. It should be noted that the pH value calculated according to the formula can fluctuate by ± 0.02.

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An introduction to pembrolizumab (Keytruda®) and its common usage and dosage.👀👀👀

Pembrolizumab is a monoclonal antibody. It is a programmed death receptor-1 (PD-1) blocker. The PD-1 receptor expressed by T cells binds to its ligands PD-L1 and PD-L2, thereby inhibiting T cell proliferation and cytokine production. PD-1 ligands are upregulated in some tumor cells. Signaling in this pathway can help inhibit active T cell immune surveillance of tumors. Pembrolizumab can bind to the PD-1 receptor. Blocking the binding of PD-1 to PD-L1 and PD-L2 will relieve the suppression of immune responses mediated by the PD-1 pathway. Therefore, the growth of tumor cells will also be inhibited. Pembrolizumab can be used clinically to treat a variety of cancers.

Common Pediatric Usage and Dosage of Pembrolizumab:

Indications	Usual dose for adults	Usual dose for children
Melanoma	For the treatment of unresectable or metastatic melanoma that has failed first-line therapy   200 mg once every three weeks or 400 mg once every six weeks until disease progression or unacceptable toxicity, or up to 12 months.	For adjuvant treatment of melanoma in children 12 years and older.   2 mg/kg every 3 weeks, up to 200 mg. Until disease progression, unacceptable toxicity, or up to 12 months.
Non-small cell lung cancer (NSCLC)	It is used as a first-line monotherapy for locally advanced or metastatic non-small cell lung cancer with negative epidermal growth factor receptor (EGFR) gene mutation and negative anaplastic lymphoma kinase (ALK) as assessed by PD-L1 tumor proportion score (TPS) ≥ 1%. It is used in combination with carboplatin and paclitaxel for the first-line treatment of patients with metastatic squamous non-small cell lung cancer.   The recommended dose for monotherapy or combination chemotherapy is 200 mg once every three weeks or 400 mg once every six weeks.   Monotherapy or combination chemotherapy: until disease progression or unacceptable toxicity, or up to 24 months.   Adjuvant monotherapy: until disease progression or unacceptable toxicity, or up to 12 months.   For resectable non-small cell lung cancer, if it is given on the same day as chemotherapy, it should be given before chemotherapy. Neoadjuvant combination chemotherapy for 12 weeks or until disease progression that precludes radical surgery or unacceptable toxicity, followed by pembrolizumab as a single-agent adjuvant therapy after surgery for 39 weeks or until disease recurrence or unacceptable toxicity.
Esophageal cancer	Pembrolizumab is used in combination with fluorouracil and platinum chemotherapy for the first-line treatment of patients with locally advanced, unresectable or metastatic esophageal or gastroesophageal junction cancer. Pembrolizumab can also be used to treat patients with locally advanced or metastatic esophageal squamous cell carcinoma (ESCC) whose tumors express PD-L1 (CPS ≥ 10) and who have failed previous first-line systemic therapy.   The recommended dose for monotherapy or in combination with chemotherapy is 200 mg once every three weeks or 400 mg once every six weeks until disease progression or unacceptable toxicity, or up to 24 months. If pembrolizumab is administered on the same day as chemotherapy, it should be administered before chemotherapy.
Classical Hodgkin's lymphoma (cHL)	Recommended monotherapy dose: 200 mg once every three weeks or 400 mg once every six weeks until disease progression or unacceptable toxicity, or up to 24 months. (For patients with cHL, an additional 400 mg dose is recommended every six weeks.)	2 mg/kg once every 3 weeks, up to a maximum of 200 mg, until disease progression or unacceptable toxicity, or up to 24 months.
Primary mediastinal large B-cell lymphoma (PMBCL)	Recommended monotherapy dose: 200 mg once every three weeks or 400 mg once every six weeks until disease progression or unacceptable toxicity, or up to 24 months. (For adult patients with PMBCL, an additional 400 mg dose is recommended every six weeks.)	2 mg/kg once every 3 weeks, up to a maximum of 200 mg, until disease progression or unacceptable toxicity, or up to 24 months.
Urothelial carcinoma	Pembrolizumab is indicated for the treatment of patients with locally advanced or metastatic urothelial carcinoma who are not eligible for cisplatin-containing chemotherapy. Pembrolizumab is indicated for the treatment of patients with BCG-unresponsive, high-risk, non-muscle invasive bladder cancer (NMIBC) with carcinoma in situ (CIS) with or without papillary tumors who are not eligible or who choose not to undergo cystectomy.   Recommended dose: 200 mg every three weeks or 400 mg every six weeks until persistent or recurrent high-risk urothelial carcinoma, disease progression, or unacceptable toxicity, or up to 24 months.
High-microsatellite instability/mismatch repair deficiency cancer	Recommended monotherapy dose: 200 mg once every three weeks or 400 mg once every six weeks until disease progression or unacceptable toxicity, or up to 24 months.	2 mg/kg once every 3 weeks, up to a maximum of 200 mg, until disease progression or unacceptable toxicity, or up to 24 months.
Gastric cancer	Pembrolizumab can be used as first-line treatment for patients with locally advanced unresectable or metastatic HER2-positive gastric or gastroesophageal junction adenocarcinoma.   Pembrolizumab should be given before trastuzumab and chemotherapy. The dose is 200 mg every three weeks or 400 mg every six weeks until disease progression or unacceptable toxicity or up to 24 months.
Cervical cancer	Pembrolizumab can be used with or without bevacizumab for the treatment of patients with persistent, recurrent, or metastatic cervical cancer whose tumors express PD-L1 (CPS ≥ 1).   Pembrolizumab should be given before bevacizumab. The dose is 200 mg every three weeks or 400 mg every six weeks until disease progression or unacceptable toxicity or up to 24 months.
Hepatocellular carcinoma (HCC)	Pembrolizumab is used to treat hepatocellular carcinoma in patients who have received prior sorafenib or oxaliplatin-containing chemotherapy.   Recommended dose for monotherapy: 200 mg every three weeks or 400 mg every six weeks until disease progression or unacceptable toxicity or up to 24 months.
Merkel cell carcinoma (MCC)	Pembrolizumab is used to treat adult patients with recurrent locally advanced or metastatic Merkel cell carcinoma.   Recommended dose: 200 mg every three weeks or 400 mg every six weeks until disease progression or unacceptable toxicity or up to 24 months.	Pembrolizumab is used to treat pediatric patients with Merkel cell carcinoma.   2 mg/kg once every 3 weeks, up to a maximum of 200 mg, until disease progression or unacceptable toxicity, or up to 24 months.
Renal cell carcinoma (RCC)	Pembrolizumab is indicated as first-line treatment for adult patients with advanced renal cell carcinoma. Adjuvant treatment for patients with renal cell carcinoma who are at intermediate or high risk of recurrence after nephrectomy or nephrectomy and resection of metastatic disease   200 mg every three weeks or 400 mg every six weeks.   Combined with oral axitinib (5 mg twice a day) or lenvatinib (20 mg once a day). When pembrolizumab is used in combination with axitinib, it may be considered to increase the dose of axitinib above the initial dose of 5 mg at intervals of six weeks or longer.   Duration of monotherapy: until disease progression or unacceptable toxicity or up to 12 months.   Duration of Combination Therapy: Until disease progression or unacceptable toxicity or Pembrolizumab is given for up to 24 months.
Endometrial cancer	Pembrolizumab combined with lenvatinib can be used in patients with non-MSI-H pMMR advanced endometrial cancer who have disease progression after prior systemic therapy and are not suitable for curative surgery or radiotherapy: 200 mg once every three weeks or 400 mg once every six weeks, combined with lenvatinib 20 mg once daily, until disease progression or unacceptable toxicity or pembrolizumab for up to 24 months.   Monotherapy can be used to treat patients with MSI-H/dMMR advanced endometrial cancer who have disease progression after prior systemic therapy and are not candidates for curative surgery or radiation therapy in any setting: 200 mg every three weeks or 400 mg every six weeks until disease progression or unacceptable toxicity or up to 24 months.
High tumor mutation burden cancer	Pembrolizumab is indicated for the treatment of adult patients with unresectable or metastatic solid tumors with high tumor mutational burden (TMB-H, ≥10 mutations/megabase/Mb) who have progressed after prior therapy and have no satisfactory alternative treatment options.   Recommended dose for monotherapy: 200 mg every three weeks or 400 mg every six weeks until disease progression or unacceptable toxicity or up to 24 months.	Pembrolizumab can be used to treat pediatric cancers with high tumor mutation burden.   Recommended dose: 2 mg/kg once every 3 weeks, up to a maximum of 200 mg, until disease progression or unacceptable toxicity, or up to 24 months.
Cutaneous squamous cell carcinoma (cSCC)	Pembrolizumab can be used to treat patients with recurrent or metastatic cSCC or locally advanced cSCC that is not curable with surgery or radiation therapy.   Recommended dose for monotherapy: 200 mg every three weeks or 400 mg every six weeks until disease progression or unacceptable toxicity or up to 24 months.
Triple-negative breast cancer (TNBC)	Pembrolizumab can be used in combination with neoadjuvant chemotherapy and continued as an adjuvant pembrolizumab monotherapy after surgery in patients with early-stage, high-risk TNBC whose tumors express PD-L1 (CPS ≥ 20) as assessed by a well-validated test.   In neoadjuvant therapy, patients should receive pembrolizumab 200 mg every three weeks for eight times or 400 mg every six weeks for four times, or until disease progression precluding radical surgery or unacceptable toxicity, followed by adjuvant pembrolizumab monotherapy. In adjuvant monotherapy, pembrolizumab is given at 200 mg every three weeks for nine times or 400 mg every six weeks for five times, or until disease relapse or unacceptable toxicity.   If patients have disease progression that precludes radical surgery or experience intolerable pembrolizumab-related toxicity during neoadjuvant therapy, they should not continue to receive adjuvant pembrolizumab monotherapy.

No dose adjustment is required for patients with mild hepatic impairment, mild or moderate renal impairment, and the elderly.

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An introduction to Nivolumab (Opdivo®) and its common usage and dosage.(Part 2)👀👀👀

The introduction to Nivolumab (Opdivo®) Part. 2. Nivolumab is recommended for the treatment of a variety of malignancies in children aged 12 years and older.

Common Pediatric Usage and Dosage of Nivolumab:

Recommended dose of nivolumab monotherapy:

Indications	Dosage	Duration
Unresectable or metastatic melanoma	For pediatric patients weighing ≥40 kg: Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes.	Patients were treated until disease progression or unacceptable toxicity.
	For pediatric patients weighing ≥40 kg: Once every two weeks, 3 mg/kg each time, intravenous infusion over 30 minutes. or Once every four weeks, 6 mg/kg each time, intravenous infusion over 30 minutes.
Adjuvant therapy for melanoma	For pediatric patients weighing ≥40 kg: Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes.	Patients were treated until disease progression or unacceptable toxicity, but not longer than one year.
	For pediatric patients weighing ≥40 kg: Once every two weeks, 3 mg/kg each time, intravenous infusion over 30 minutes. or Once every four weeks, 6 mg/kg each time, intravenous infusion over 30 minutes.
Microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) metastatic colorectal cancer	For pediatric patients weighing ≥40 kg: Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes.	Patients were treated until disease progression or unacceptable toxicity.
	For pediatric patients weighing ≥40 kg: Once every two weeks, 3 mg/kg each time, intravenous infusion over 30 minutes.

Recommended doses of nivolumab when used in combination with other drugs:

Indications	Dosage	Duration
Unresectable or metastatic melanoma	Once every three weeks, 1 mg/kg each time, intravenous infusion over 30 minutes, combined with ipilimumab 3 mg/kg.	Combination therapy with ipilimumab. Use up to four times or until unacceptable toxicity occurs, whichever comes first.
	For pediatric patients weighing ≥40 kg: Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes. Combined treatment with ipilimumab 3 mg/kg.	After completing 4 combination treatments, single-agent therapy was used until disease progression or unacceptable toxicity occurred.
	For pediatric patients weighing ≥40 kg: Once every two weeks, 3 mg/kg each time, intravenous infusion over 30 minutes. or Once every four weeks, 6 mg/kg each time, intravenous infusion over 30 minutes.
Microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) metastatic colorectal cancer	Once every three weeks, 3 mg/kg each time, intravenous infusion over 30 minutes, combined with ipilimumab 1 mg/kg.	Combined treatment with ipilimumab for four doses.
	Pediatric patients 12 years and older weighing ≥40 kg: Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes. Combined treatment with ipilimumab 1 mg/kg.	After completing 4 combination treatments, single-agent therapy was used until disease progression or unacceptable toxicity occurred.
	Pediatric patients 12 years and older weighing ≥40 kg: Once every two weeks, 3 mg/kg each time, intravenous infusion over 30 minutes. Combined treatment with ipilimumab 1 mg/kg.

Preparation method of Nivolumab injection.

Nivolumab is generally diluted with 0.9% sodium chloride injection or 5% glucose injection to prepare an infusion solution with a concentration of 1 mg/ml to 10 mg/ml.

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An introduction to Nivolumab (Opdivo®) and its common usage and dosage.(Part 1)👀👀👀

Nivolumab (Opdivo®) is a monoclonal antibody. It binds to the PD-1 receptor,
thereby blocking the interaction of the PD-1 receptor with PD-L1 and PD-L2. Immunosuppressive responses mediated by the PD-1 pathway will be blocked (such as tumor immune responses). Nivolumab can be used to treat a variety of malignant tumors in adults. Nivolumab is commonly used in the form of injection.

Common Adult Usage and Dosage of Nivolumab:

Recommended dose of nivolumab monotherapy:

Indications	Dosage	Duration
Non-small cell lung cancer (including metastatic) Head and Neck Squamous Cell Carcinoma Gastroesophageal junction adenocarcinoma	Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes. or Once every two weeks, 3 mg/kg each time, intravenous infusion over 30 minutes.	Until disease progression or unacceptable toxicity.
Advanced renal cell carcinoma Classical Hodgkin's lymphoma Locally advanced or metastatic urothelial carcinoma Esophageal squamous cell carcinoma Unresectable or metastatic melanoma Microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) metastatic colorectal cancer	Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes.	Until disease progression or unacceptable toxicity.
Adjuvant therapy for melanoma Adjuvant therapy for urothelial carcinoma (UC)	Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes.	Until disease progression or unacceptable toxicity occurs, no longer than one year.
Adjuvant therapy after resection of esophageal or gastroesophageal junction cancer	Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes. Continue for 16 weeks, then 480 mg every four weeks	Until disease progression or unacceptable toxicity. The total course of treatment is one year.

Recommended doses of nivolumab when used in combination with other drugs:

Indications	Dosage	Duration
Unresectable or metastatic melanoma	Once every three weeks, 1 mg/kg each time, intravenous infusion over 30 minutes, combined with ipilimumab 3 mg/kg intravenous injection.	Administer in combination with ipilimumab for up to four times or until unacceptable toxicity occurs, whichever occurs first.
	Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes.	After completing four cycles of combination therapy, the drug was administered as a single agent until disease progression or unacceptable toxicity.
Neoadjuvant therapy for resectable non-small cell lung cancer	Nivolumab 360 mg combined with platinum-containing drugs were infused on the same day once every three weeks, intravenously over 30 minutes.	Combined with a platinum-containing doublet chemotherapy regimen for a total of three cycles.
Metastatic non-small cell lung cancer expressing PD-L1	360 mg once every three weeks, intravenous infusion over 30 minutes. Ipilimumab was administered as an intravenous infusion of 1 mg/kg over 30 minutes every 6 weeks.	Administer ipilimumab in combination until disease progression or unacceptable toxicity or up to two years in patients without disease progression.
Metastatic or recurrent non-small cell lung cancer	360 mg once every three weeks, intravenous infusion over 30 minutes. Ipilimumab was administered as an intravenous infusion of 1 mg/kg over 30 minutes every 6 weeks. Platinum-based doublet chemotherapy every three weeks	Administer ipilimumab in combination until disease progression or unacceptable toxicity or up to two years in patients without disease progression.
		Two cycles of histology-based platinum doublet chemotherapy.
Malignant pleural mesothelioma	Nivolumab 360 mg once every three weeks is administered as an intravenous infusion over 30 minutes. Ipilimumab was administered as an intravenous infusion of 1 mg/kg over 30 minutes every 6 weeks. Or Nivolumab 3 mg/kg every two weeks.	Administer ipilimumab in combination until disease progression or unacceptable toxicity or up to two years in patients without disease progression.
Advanced renal cell carcinoma	Nivolumab 3 mg/kg once every 3 weeks, with ipilimumab 1 mg/kg, was infused intravenously over 30 minutes.	Use in combination with ipilimumab for four doses.
	Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes.	Nivolumab: Until disease progression, unacceptable toxicity or up to two years.
	Nivolumab and cabozantinib 40 mg are taken orally once daily without food.	Cabozantinib: until disease progression or unacceptable toxicity.
	Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes.	After completing four doses of ipilimumab combination therapy, it was administered as a single agent until disease progression or unacceptable toxicity.
Microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) metastatic colorectal cancer	Nivolumab 3 mg/kg once every 3 weeks, with ipilimumab 1 mg/kg, was infused intravenously over 30 minutes.	Combined with ipilimumab for four doses.
	Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes.	After completing four doses of combination therapy, the drug was administered as a single agent until disease progression or unacceptable toxicity.
Hepatocellular carcinoma	Nivolumab 3 mg/kg once every 3 weeks, with ipilimumab 1 mg/kg, was infused intravenously over 30 minutes.	Combined with ipilimumab for four doses.
	Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes.	After completing four doses of combination therapy, the drug was administered as a single agent until disease progression or unacceptable toxicity.
Esophageal squamous cell carcinoma	Once every two weeks, 240 mg each time, intravenous infusion over 30 minutes. or Once every four weeks, 480 mg each time, intravenous infusion over 30 minutes. Nivolumab administered in combination with fluoropyrimidine-containing and platinum-containing chemotherapy	Nivolumab: Until disease progression, unacceptable toxicity or up to two years.
		Chemotherapy: Until disease progression or unacceptable toxicity.
	3 mg/kg once every two weeks, intravenous infusion over 30 minutes. or 360 mg once every three weeks, intravenous infusion over 30 minutes. Combined with ipilimumab, 1 mg/kg per dose is administered intravenously over 30 minutes every six weeks.	Use in combination with ipilimumab until disease progression, unacceptable toxicity, or up to two years.
Gastric cancer, gastroesophageal junction cancer, esophageal adenocarcinoma	240mg once every two weeks, intravenous infusion for 30 minutes, fluoropyrimidine-containing and platinum-containing chemotherapy once every two weeks or 360 mg once every three weeks, intravenous infusion for 30 minutes, fluoropyrimidine-containing and platinum-containing chemotherapy once every three weeks	Until disease progression, unacceptable toxicity or up to two years.

Preparation method of Nivolumab injection.

Nivolumab is generally diluted with 0.9% sodium chloride injection or 5% glucose injection to prepare an infusion solution with a concentration of 1 mg/ml to 10 mg/ml.

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