The condition was formerly known as a "hare-lip" because of its resemblance to a hare or rabbit, but that term is now generally considered to be offensive. Signs and symptoms
Cleft lip
If the cleft does not affect the palate structure of the mouth, it is referred to as cleft lip. Cleft lip is formed in the top of the lip as either a small gap or an indentation in the lip (partial or incomplete cleft), or it continues into the nose (complete cleft). Lip cleft can occur as a one-sided (unilateral) or two-sided (bilateral) condition. It is due to the failure of fusion of the maxillary prominence and medial nasal processes (formation of the primary palate). A mild form of a cleft lip is a microform cleft. A microform cleft can appear as small as a little dent in the red part of the lip or look like a scar from the lip up to the nostril. In some cases muscle tissue in the lip underneath the scar is affected and might require reconstructive surgery. It is advised to have newborn infants with a microform cleft checked with a craniofacial team as soon as possible to determine the severity of the cleft. Cleft palate
Cleft palate is a condition in which the two plates of the skull that form the hard palate (roof of the mouth) are not completely joined. The soft palate is in these cases cleft as well. In most cases, cleft lip is also present.
The most common causes are (in no particular order) infections, interstitial lung disease, and pulmonary oedema. Diagnosis
Type 1
Type 1 respiratory failure is defined as a low level of oxygen in the blood (hypoxemia) with either a standard (normocapnia) or low (hypocapnia) level of carbon dioxide (PaCO2) but not an increased level (hypercapnia). It is typically caused by a ventilation/perfusion (V/Q) mismatch; the volume of air flowing in and out of the lungs is not matched with the flow of blood to the lungs. The fundamental defect in type 1 respiratory failure is a failure of oxygenation characterized by:

This type of respiratory failure is caused by conditions that affect oxygenation, such as:

Low ambient oxygen (e.g. at high altitude)
Ventilation-perfusion mismatch (parts of the lung receive oxygen but not enough blood to absorb it, e.g. pulmonary embolism)
Alveolar hypoventilation (decreased minute volume due to reduced respiratory muscle activity, e.g. in acute neuromuscular disease); this form can also cause type 2 respiratory failure if severe. Diffusion problem (oxygen cannot enter the capillaries due to parenchymal disease, e.g. in pneumonia or ARDS)
Shunt (oxygenated blood mixes with non-oxygenated blood from the venous system, e.g. right to left shunt)

Type 2
Hypoxemia (PaO2 <8kPa or normal) with hypercapnia (PaCO2 >6.0kPa). The basic defect in type 2 respiratory failure is characterized by:

Type 2 respiratory failure is caused by inadequate alveolar ventilation; both oxygen and carbon dioxide are affected. Defined as the buildup of carbon dioxide levels (PaCO2) that has been generated by the body but cannot be eliminated.